# Incerdibly lazy question about HELIX DSP software and REW and Dirac and is there a Car DSP for dummies book? (I have audiofrogs one seat tuning guide)



## Sam Spade (Mar 16, 2020)

Hi all

I have a single din Kenwood KDC-X7100DAB, a helix ultra, a fully sound deadened 4WD station wagon and:

front speakers Hertz Mille MLK 1650.3 legend -2Way
rear speakers Hertz Mille MLK 165.3 legend - 2Way
subs are two Hertz EBXF20.5 - 8" Enclosed Subwoofer boxes
amps three Hertz HP802 SPL - class AB Stereo Amplifier 330rms into 4 ohms
The system was installed and sounded great. Then the helix ultra went in and was tuned by ear. Sounded next level. Once I got an MTK1 I've managed an autotune with my installer and it took the system to another level again. Then we took the FLAC files from an Astell and Kern USB output converted to SPDIF and put it into the helix via the 75 ohm coax. Went up a notch again. It just keeps getting better which is very gratifying.

Waiting for a WIFI controller, a HEC USB module and a URC.3 to finish this stage of the install which are somewhere between here and Germany. .

So now I'm looking to move forward with tuning. I know it's lazy and I should do the google thing but you guys are so helpful. Will I get an advantage from using REW and/or Dirac? Or can I just keep using the helix OEM software and get as good a result. And if I should be using REW and/or Dirac how will they help?

Also I have audiofrogs guide to a one seat tuning process but are there any good entry level books for this?


Thanks
Lazy Sam


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## SQ_Blaze (Sep 29, 2008)

REW is just software to measure the system. As long as you're using the Helix, you have no choice but to use the software that comes and works with it.


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## Sam Spade (Mar 16, 2020)

SQ_Blaze said:


> REW is just software to measure the system. As long as you're using the Helix, you have no choice but to use the software that comes and works with it.


Yep Blaze I absolutely get that The helix OEM software is needed to control the ultra. I should have been clearer with my question. Should I be using REW or Dirac or any other software to get me information that will help me by giving me information to better tune the Ultra using the helix OEM software?


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## jtrosky (Jul 19, 2019)

You really can't use Dirac with the Helix - the DSP hardware has to be designed with Dirac in mind to use Dirac. 

You would use REW for tuning for the most part. It's _fantastic_ for EQ work using pink noise.

REW, REW, REW - you'll want to learn how to use it! 

Also, Andy from Audiofrog has an excellent document that describes the overall tuning process in great detail - and also explains _why_, which is awesome. 

Here is a link if you don't already have it:

https://testgear.audiofrog.com/wp-c...Process-and-Some-Notes-About-Why-it-Works.pdf

Skizer has a YouTube video on EQ'ing with REW that is helpful.

Kyle Ragsdale also has a whole series of tuning videos on YouTube. 

I found that you just gets bits of information for here and there. 

Phase is a lot harder. You can apparently work on it somewhat with REW, but a real app for phase, Smaart, is MUCH better - but it costs like $1k US just for the software.  I've found that major phase issues are usually visible in your pink noise measurements - and then you can work on fixing them (I've fixed a few with allpass filters, for example).

Hope that helps somewhat.


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## jtrosky (Jul 19, 2019)

ALso - there are some great thread over on caraudiojunkies as well.

Not sure if it will allow to post a link but I'll try - this is a general Helix DSP.3 help thread that contains some useful info:


```
https://www.caraudiojunkies.com/showthread.php?3525-Helix-DSP-3-help-thread
```


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## Sam Spade (Mar 16, 2020)

jtrotsky that's REALLY REALLY great thanks. I have the audiofrog guide I just need to read it. I haven't subscribed to caraudiojunkies yet, I will. I learn better by reading than watching videos but in this modern world that's not always an option. I have REW on my laptop. I'll fire it up and I guess if I have it on my desktop along with the Helix software I can run that in demo mode and mess around with the results and data in a nice office chair and then dump what I need onto the laptop and go back outside to the car?

It seems that the top end minidsp with FIR and dirac live deals with phase really well, but the helix ultra and DSP.3 do most other things better? Is that correct? But as I have an ultra that decision is made. and it sounds so unbelievably good I'm not going back. 

although if I do have serious phase problems didn't I read somewhere here you can run a specialised FIR processor before your IIR processor? I'll have to chase up the thread. But I guess I'll wait and see what problems I have first before I go looking for solutions. 

I thnk what I'll do is try and learn as much as I can then if I hit a wall beg SkizeR for a remote tune  

cheers
Sam


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## jtrosky (Jul 19, 2019)

Sam Spade said:


> jtrotsky that's REALLY REALLY great thanks. I have the audiofrog guide I just need to read it. I haven't subscribed to caraudiojunkies yet, I will. I learn better by reading than watching videos but in this modern world that's not always an option. I have REW on my laptop. I'll fire it up and I guess if I have it on my desktop along with the Helix software I can run that in demo mode and mess around with the results and data in a nice office chair and then dump what I need onto the laptop and go back outside to the car?
> 
> It seems that the top end minidsp with FIR and dirac live deals with phase really well, but the helix ultra and DSP.3 do most other things better? Is that correct? But as I have an ultra that decision is made. and it sounds so unbelievably good I'm not going back.
> 
> ...


You are correct - if you add a piece of MiniDSP equipment that supports Dirac into the chain before your Helix, you can use FIR filters and Dirac as well - it just requires more hardware. Honestly, if I was going that route, I'd probably just buy the MiniDSP 8x12v2 w/Dirac built-in, instead of the Helix, but....

It's funny you mention the part about tuning on your PC in the comfort of your chair - and sharing it with your laptop. I wrote up this procedure for another member, so I'll share it here as well - it's basically how I do my EQ work - I do most of it on my home PC, in the comfort of my chair. I only sit in the car to take measurements, I then do the vast majority of the EQ work in the house, in the AC and in comfort.  I use Google Drive to automatically "share" everything between my laptop and PC, so it's all automatically on both devices. Here is the guide I wrote up:

-----------------------------------------------------------


*In-home car tuning guide*

Here is how I go about tuning my vehicle - at least until I get it matching my house curve - at that point, you'll have to adjust as-desired, while in the car itself.

First though, I have to describe my setup. I have a Lenovo Yoga 3 Pro "laptop" (can also be used as a tablet). On that device _and_ my home PC, I setup the Google Drive app and store my Helix tune files somewhere on that Google Drive. I also store my REW measurements on Google Drive. Doing this allows all of my Helix Tunes and REW measurements to always be "in sync" between my home PC and my Lenovo laptop. So if I update my Helix tune on my home PC, it will also be on my laptop when I go out to my car (which isn't connected to my home wifi anymore at that point - it's connected to my Helix wifi adapter). Any REW measurements I take while in the car, will also be available on my home PC when I come back into the house and connect my laptop to my home wifi. Google Drive is a key component to being able to tune in the house! 


Here is the overall process:

1. Go out to car and take "base" measurements of each individual speaker - before ANY EQ. Once you have these measurements, you can then EQ to your hearts content inside the house on your PC using the REW "predicted" feature. I work on my EQ until the "predicted" response matches my house curve.

2. I then export the REW individual speaker EQ settings to a text file on my home PC.

3. On my home PC, I then load the Helix software and import the individual speaker EQ settings for each channel using the Helix "R" key (to import REW-exported EQ settings). I then save the tune to a new name (such as "JT450" (my own 450hz target curve) - which again, is stored on my Google Drive.

4. Before I go out to the car, I boot up the laptop in order for it to sync with Google Drive while on my home wifi network.

5. I then go out to the car, load up the Helix software and load the tune I created in the house. Then I take new measurements of each speaker, as well as speaker pairs, left/right side and/or entire front stage measurement. I only spend enough time in the car to get updated measurements. 

6. When back in the house, I let the laptop sync with my Google Drive so that I can then load the new REW measurements on my home PC.

7. I then check/manually adjust the individual speaker results to match the curve again (the "predicted" response is never 100% correct).

8. At this point, you have to update the Helix EQ measurements manually (should only be a handful of changes for each speaker).

I this point, I repeat steps 4-9 until I match my curve as best as possible. The only time spent in the car is that time to take new REW measurements. This also helps not to run down the car battery too much. I typically throw a charger on the car after I take new measurements so that the battery is 100% full when I go back out to the car for new measurements again.

Regarding REW, I've learned the REW EQ system VERY well. Sometimes, I don't even use the REW auto-EQ - I just manually EQ things. I can usually accomplish my goal with less filters when I do it manually. It's to the point where I just know what Q values to use just by looking at the response. Again, using the "predicted" result is AWESOME. It basically shows what the response is going to be with your new EQ adjustments (and it's pretty damn good!). The REW "overlays" windows is the key - you can switch between the response and the predicted response very easily and see how the EQ changes affect things. The REW "EQ Filters" is also key - just select "PK" for the type, select a frequency, gain and Q and see how that affects the "predicted" response. You can also use the little arrows to adjust the exact freq/Q while watching the predicted response change in the "Overlays" window. 

Hope that helps! Let me know if you have any questions. Again, Google Drive setup is a huge time saver. I always have my tune and REW measurement files on my home PC and laptop and can use/adjust them on either device. I do most of my EQ work on my home PC, where it's easier due to a big monitor, full mouse, etc.

Let me know what you think of this "guide" - and what I can improve. I'll probably post it on the forums in case anyone else wants to do the bulk of the tuning in the comfort of their home.


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## Don Camillo (Jul 13, 2017)

A Very quick read tells me this is a great thread to follow 👌👍
And that there is a lot to learn for me. 😃


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## SQ_Blaze (Sep 29, 2008)

This reminds me... I need to find my miniDSP USB mic to use with REW. Sucks when you move and misplace things.


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## RockitFX (Aug 22, 2018)

Are we supposed to be sitting in the car when we take response measurements? This isn't clear in any of the tutorials I've read, but I can imagine pros & cons each way.


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## SQ_Blaze (Sep 29, 2008)

I don't. I'm outside the car doing the measurements and initial tuning. Once I'm happy with the curve, then I get in and tweak to taste.


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## geolemon (Aug 15, 2005)

I was debating whether the cost difference between the 8x12 miniDSP and the Helix Ultra could be justified, but to be fair the 8x12 with Dirac is the one that has comparable features, and that brings the two pretty close to each other in price... although once you add the Director, there's again a decent difference between them. I'm still undecided. So in the meantime, a specific question:

For both, if anyone knows both (Dirac vs Helix auto-EQ):
If you run a sweep for the auto-EQ, that simply creates an EQ curve - one that you can subsequently further tweak to your preference, right?

I imagine that's the case for both Dirac and Helix, but certainly that's something to know before buying. Can anyone confirm?


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## geolemon (Aug 15, 2005)

jtrosky said:


> It's funny you mention the part about tuning on your PC in the comfort of your chair - and sharing it with your laptop. I wrote up this procedure for another member, so I'll share it here as well - it's basically how I do my EQ work - I do most of it on my home PC, in the comfort of my chair. I only sit in the car to take measurements, I then do the vast majority of the EQ work in the house, in the AC and in comfort.  I use Google Drive to automatically "share" everything between my laptop and PC, so it's all automatically on both devices. Here is the guide I wrote up...
> 
> Let me know what you think of this "guide" - and what I can improve. I'll probably post it on the forums in case anyone else wants to do the bulk of the tuning in the comfort of their home.


I completely follow that and agree that having a "from the comfort of the sofa" option would be nice...
...but I see a whole lot of back-and-forth, and having-to-sync in between.

So - qualifying this by saying "my career these days is an IT consultant and QA specialist" - so my brain instinctively makes me ask these things:  

Is there a way to simply have your laptop (or home PC) connected to the Helix (or miniDSP) DSP from inside the home to begin with? 
I actually happen to be of the camp where I want to be inside the car for tuning (to account for "me" messing up some acoustics), but I'm fine with leaving that for a final tweak.
To me, if it's possible, I'd rather run the sweeps and all from my home - which would also simplify your steps, of course.
Sure the car would need to be key-on (unless your remote starter happens to activate the aux circuit the stereo is on - mine does not), but that's OK with me.


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## jtrosky (Jul 19, 2019)

geolemon said:


> I completely follow that and agree that having a "from the comfort of the sofa" option would be nice...
> ...but I see a whole lot of back-and-forth, and having-to-sync in between.
> 
> So - qualifying this by saying "my career these days is an IT consultant and QA specialist" - so my brain instinctively makes me ask these things:
> ...


Well, it's really up to each individual person. For me, I'm never done tuning since I'm still learning, upgrading parts, etc. So I don't do all of this in one long "session". I'll take my initial measurements (before any EQ) and then I may not actually do the EQ work in REW until hours (or even days later). So then I'll do my thing on my home PC when I have time and then at some later date and/or time, go back to the car and apply the updated tune, take new measurements and a quick 5 minute listening session to "evaluate" the latest changes. Then, it may be hours and/or days before I actually go back to the car with an updated tune based on those measurements. So it's not like I'm going back and forth to car constantly for hours or anything. It allows me to work on it as I have time and/or energy. 

By the way, I'm also in IT (been doing Unix administration work for 25+ years), so I get where you are coming from. 

My laptop would not be able to connect to the Helix wifi adapter in my car while I'm in my house - too far away. Besides, I need to be in the car to take new measurements and/or listen to the changes anyway, so I'm not sure i see the advantage of that - especially if you sit in the car to take the measurements like I do (moving MIC measurements).

I haven't messed with sweeps at all - just tuning via pink noise. So I can get all of the measurements I need in a few minutes - so I spend as little time actually in the car until I'm to the point where I'm making "by ear" changes while listening. 

Like I said, everyone has different circumstances. The procedure above is just what I find works well for me. The laptop and home PC sync automatically with Google Drive, so I don't have to do any manual file copies or anything - it's all automatic and just allows me to to take/view measurements and view/modify the Helix tune from either device.


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## geolemon (Aug 15, 2005)

Also, I've been thinking about basically the same thing the OP is asking about, for a while now.

There's another thread here somewhere that I commented on over the weekend or a few days back, because I was struck by how nebulously and non-objectively we seem to talk about DSP on all these forums, despite their growing popularity. Yeah - of course it's confusing when we discuss them so nebulously. I made the analogy there, that it would be like discussing subwoofers if there were no such thing as T/S specs, if there were no enclosure modeling software.
Imagine if all those "what subwoofer is best?" threads just stayed at that level of detail, with one person making claims about how this one was "better than" that one, "because the quality" is better, or "because the flexibility" is better. Can you imagine having meetings at your company, where people only discussed and compared subjectively? $3M project budgets based on one team member simply saying "I prefer this UI over that UI"? There's got to be a better way.

So - again qualifying this as "These days I'm an IT consultant with a QA specialist's anal level of instinct for identifying risks and incorrectness"...
...I like to think of these units like Lego blocks. I blame lots of my hobbies on Lego blocks - but I really do think it helps me traverse the spectrum between big-picture overviews to finite details.
A DSP is pretty intimidating if you think of it as "a DSP".

I think it's less intimidating if you think of it as the component functions that actually make it up. At least if I were writing the Idiot's Guide to DSP, I'd break it down like this:

*Input channels.* What you can do with them (combine them, split them, flip phase, etc - and why)
*Crossovers/filters*. What they do, how to set them up. You'd do this separately anyway, even if you didn't have a DSP. Why you might adjust them during tuning.
*EQ.* 1/3 octave vs parametric. What they do, how to set them up. Why you might need to revisit this after making other tweaks elsewhere.
*Auto-EQ.* If it exists, what it does. Why you might need to tweak your EQ after auto EQ - especially if making other tweaks elsewhere. 
*Mixer.* Advanced combining or splitting of processed channels - why you need to know if this exists logically before or after other processing in your DSP.
*Built-in processing.* Some RTAs have 5.1 processing or simulation from stereo, or other features, to widen or deepen imaging, etc. Why you'd use these, or shop for DSPs that can.
*RTA.* How to do it, how to interpret the results, how to decide what to do next (how to identify phase issues vs EQ issues vs placement/aiming issues vs crossover issues, etc)
Yeah, it's a ton of stuff packed into a tiny box, and yeah, an experienced installer will be able to set this up much more quickly than a novice.

But if you break it up into those Lego-block pieces above, even a notice could get a better result than having no DSP, if they simply keep these simplified goals in mind, and think of them as steps that you handle separately:

*Input channels.* Usually it's just "what your head unit supplies" - could be 2 RCAs, could be front/rear RCAs, could be front/rear/sub RCAs. The DSP works with whatever you have.
Plug them in, then on to the next step:
*Crossovers/filters*. You want your sub to just play sub frequencies. You want your mids just to play mids. You want your tweeters just to play top octaves. Etc. 
Next step...
*EQ.* Start with it flat. After you run an RTA sweep (below), you'll come back to this, to try to adjust the EQ to offset the dips and peaks. Run another RTA sweep, see if it worked... repeat.
*Auto-EQ.* If it exists, try it out. It makes pink noise and automatically adjusts the EQ. Keep your doors closed. Might be "good enough" and DONE.
*Mixer/outputs.* Newbie? You just need to map your inputs to outputs. You need to define a sub channel, if you have a sub amp, for example. You'll plug your RCA outputs to that and into your sub amp. Same for your front speakers... do you need separate tweeter channels? Mids? Midbass? It's really not that complex, just telling the DSP which RCA outputs you have plugged into which amps you have.
*Built-in processing.* These are just things to play with later, to see if they improve or degrade what you are hearing. Some things like "Center channel" you might not even have. Or, maybe "phantom center channel" is interesting, if you don't have an actual center channel. Or if your imaging feels too narrow, there might be something here. Give the a listen, that's basically it. Or don't.
*RTA.* It's just a measurement, to show you how far from flat you are. And "flat" isn't necessarily the goal - but if you can manipulate to "flat", you can manipulate to wherever else your preference might be.
Hopefully it's not too intimidating.

But again, I'm even finding shopping for these as somewhat intimidating, because unlike speakers with spec sheets and T/S parameters, every manufacturer's documentation is different (and in the case of Mosconi - totally missing, unless you look up their Facebook video series - which is absolutely amazingly good - crazy insanity bizzaro world stuff). It is hard to compare, even for someone who's been doing this so long as to be retired from retail, engineering, or even installing (besides 'for myself', of course). 
I'm blown away by how difficult it is just to do an A/B comparison of parameters and features. 
I'd love to see some standardization occur, that grouped the features logically sort of like what I've done above, with relevant parameters for each... and maybe even a block diagram showing the order of processing, especially important to understand what that mixer even CAN do.


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## geolemon (Aug 15, 2005)

jtrosky said:


> My laptop would not be able to connect to the Helix wifi adapter in my car while I'm in my house - too far away. Besides, I need to be in the car to take new measurements and/or listen to the changes anyway, so I'm not sure i see the advantage of that - especially if you sit in the car to take the measurements like I do (moving MIC measurements).


That's what I really meant by saving the "body in car" measurements for last.
I'm just thinking for the initial sweeps (and sorry, I instinctively say that when I mean measurements - pink noise, sweep - whatever the specific measurement tool uses), it would be great to mount a mic at ear level the static position, and do all the initial tweaking from the sofa.

Then the fine tuning with the body-in-car, the moving mic (I also don't own a rig to do that via a motor, and I would be afraid of introducing noise anyway) etc - I think of that stuff that more or less you have to be in the car at any rate, the final tweaks.

I'm with you, tuning is probably never done, simply because I'm always experimenting - but that's also why I'm frustrated at the implication that it's "so advanced" that a DIY'er can't do it, and that it's some sort of magic that only a professional installer should handle... No, think of it as smaller goals, and I think any DIYer could figure it out.
Everyone - pros included - have to learn the specifics of the software that each specific DSP maker makes... personally I can't even imagine buying a DSP and NOT learning the software, having some person who ISN'T me, basically tuning it to THEIR preference...
I fully think this is something a DIYer should learn, if they are going to take the financial plunge of all the extra channels of amplification, and the cost of the DSP. Make it yours, right? 
It's what DIY car audio is all about, IMO.


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## jtrosky (Jul 19, 2019)

geolemon said:


> personally I can't even imagine buying a DSP and NOT learning the software, having some person who ISN'T me, basically tuning it to THEIR preference...
> I fully think this is something a DIYer should learn, if they are going to take the financial plunge of all the extra channels of amplification, and the cost of the DSP. Make it yours, right?
> It's what DIY car audio is all about, IMO.


I agree 1000%.  I want to understand how it all works and be able to modify/adjust it on my own. Wouldn't want someone else tuning it. After all, my hearing and preferences are NOT the same as theirs, so what's the point? If you do it just to get a "baseline", then it still doesn't make sense to me, because you still have to learn it all in order to adjust it to your preferences after-the-fact anyway.

But like you mentioned, we're "computer people" - so we tend to think a little differently than others. We make a living off of troubleshooting and fixing problems - so I think it comes natural to us to want to know the "hows and whys".


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## SiW80 (Mar 13, 2019)

jtrosky said:


> I agree 1000%.  I want to understand how it all works and be able to modify/adjust it on my own. Wouldn't want someone else tuning it. After all, my hearing and preferences are NOT the same as theirs, so what's the point? If you do it just to get a "baseline", then it still doesn't make sense to me, because you still have to learn it all in order to adjust it to your preferences after-the-fact anyway.
> 
> But like you mentioned, we're "computer people" - so we tend to think a little differently than others. We make a living off of troubleshooting and fixing problems - so I think it comes natural to us to want to know the "hows and whys".


When do you do the time alignment - before or after the eq’ing to get the curve you want?

Does REW also give suggested TA settings?


Sent from my iPhone using Tapatalk


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## Sam Spade (Mar 16, 2020)

RockitFX said:


> Are we supposed to be sitting in the car when we take response measurements? This isn't clear in any of the tutorials I've read, but I can imagine pros & cons each way.


I would wear hearing protection if you are in the car. Especially if you did it for a living


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## jtrosky (Jul 19, 2019)

SiW80 said:


> When do you do the time alignment - before or after the eq’ing to get the curve you want?
> 
> Does REW also give suggested TA settings?
> 
> ...


You can do time alignment right away. Usually, I think people do levels, then time-alignment - but could do time-alignment first if you wanted. Target curve is mainly achieved via EQ, not time-alignment (although time-alignment can impact the frequency response as well, which is why it's usually set before EQ). There are some people talking about ways to figure out time alignment with REW on the "other" forum right now, but not sure how reliable it is. Just using tape-measure measurements is the most common way to set initial time-alignment. You can fine-tune later if needed.

Hope that helps. Anyone - feel free to correct me if I mis-stated anything.


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## Sam Spade (Mar 16, 2020)

geolemon said:


> Also, I've been thinking about basically the same thing the OP is asking about, for a while now.
> 
> There's another thread here somewhere that I commented on over the weekend or a few days back, because I was struck by how nebulously and non-objectively we seem to talk about DSP on all these forums, despite their growing popularity. Yeah - of course it's confusing when we discuss them so nebulously. I made the analogy there, that it would be like discussing subwoofers if there were no such thing as T/S specs, if there were no enclosure modeling software.
> Imagine if all those "what subwoofer is best?" threads just stayed at that level of detail, with one person making claims about how this one was "better than" that one, "because the quality" is better, or "because the flexibility" is better. Can you imagine having meetings at your company, where people only discussed and compared subjectively? $3M project budgets based on one team member simply saying "I prefer this UI over that UI"? There's got to be a better way.
> ...


That's one of the best posts ive seen here geolemon. On a similar note in a PM i asked "But i wonder since DSPs are so important in cars is it best to get a really good dsp and build your system around it or is it better to build the system then add the dsp? "

Whats even harder is once the signal processing is done a dsp back end is basically a DAC and preamp. And a chunk of carfi people seem to not realise how fundamenally important that is. And how the hell do you AB that? Thats the stuff homefi people agonise over in ab comparisons to match their speakers. 

My current thought is i bought an ultra. The local distributor said it was 90% of a brax at 25% of the cost. And told me the DSP.3 is great probably my best option and the mk2 is old architecture dont buy it. But the ultra is not only an awesomely powerful dsp it seems somewhat user friendly. AND it is a truely audiophile SQ piece of kit. I took that on trust and reputation cos i couldnt ab it. Thats one thing many carfi junkies dont seem to get. "All dsps sound the same its just the processing thats important, all amps sound the same etc". There is a chunk of discussion in homefi and headfi that is somewhat missing, even ridiculed in many carfi conversations. 

Ultras are really expensive. Not everyone can throw that cash around on a dsp. But a helix mini dsp is the same architecture? and what 1/3 the price?. But fewer features. And SQ wouldnt be as good. But im sure its a great bit of kit. 

Is it the drayton that is cheap with good reviews? Then there is mini dsp and FIR v IIR but i now hear that the top MiniDSP will do FIR and IIR and if you have a helix and need FIR theres a mini dsp unit you can slap in front of it that presumably does all its stuff in the digital domain. Now all that is seriously ****ing complicated even if you ignore SQ which can be objective measurements but also is sujective. 

So yes your idea of an evaluation framework is excellent but can you expand it to include SQ measures please 😄

Seriously that is an awesome idea and the bones of a great framework. 

Oh and its 440pm here and i couldnt sleep and got up to pee so i hope ive been coherent and civil 😄


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## Truthunter (Jun 15, 2015)

Just thought this thread needed some more info:

The MiniDSP 8x12DL does not allow the tuner to manually set up FIR filters. Dirac is an algorithm licensed from Dirac Research which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). It is not (just) an auto eq like what has been and is offered in some headunits and conventional standalone DSPs based off an RTA and should not be compared to those as such. It's also not (just) an auto amplitude & phase eq either. And it is not "just push the easy button and now you have a optimum tune" like I have seen some refer to it as.

Technical information - Dirac

The only other device on the market for 12v use that offers something similar is from Acoustic Power Labs (APL1 2ch only or built into the APL1012 DSP) which I have not used but have heard the results in several vehicles which were very, very good. I'm not sure that it actually performs the same functions as Dirac in the time domain though as it's latency is only 2.5ms whereas the MiniDSP with Dirac is 13.8ms.


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## Mauian (Jul 25, 2019)

Ha. My first career was software development. Go figure 


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## Sam Spade (Mar 16, 2020)

Truthunter said:


> Just thought this thread needed some more info:
> 
> The MiniDSP 8x12DL does not allow the tuner to manually set up FIR filters. Dirac is an algorithm licensed from Dirac Research which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). It is not (just) an auto eq like what has been and is offered in some headunits and conventional standalone DSPs based off an RTA and should not be compared to those as such. It's also not (just) an auto amplitude & phase eq either. And it is not "just push the easy button and now you have a optimum tune" like I have seen some refer to it as.
> 
> ...


Hi truthhunter

" which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). "

I assume room correction is frequency correction plus some additional types of correction? Can you expand?
Cheers sam


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## opekone (Mar 24, 2020)

Sam Spade said:


> Hi truthhunter
> 
> " which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). "
> 
> ...


According to the link it's using 9 different mic positions and an impulse response and with that the software can build a very comprehensive model of phasing. If it works half as well as it should... well then. If you have the top end version of smaart they have plugins that will do this for you. Once you have the data from multiple mics in at multiple locations then writing a match algorithm probably isn't really the hard part. In smaaart you run your mics concurrently, but it looks like dirac asks you to repeat the measurements with new mic positions and then internally overlays the impulse responses?

Who has experience with it? How new is this tech? Is it winning SQ competitions?


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## RockitFX (Aug 22, 2018)

What is this "moving mic" that was mentioned several times in this thread? I thought for measurements we were supposed to keep the mic in the exact same spot? I feel a little dumber every time I log in here....


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## Mauian (Jul 25, 2019)

RockitFX said:


> What is this "moving mic" that was mentioned several times in this thread? I thought for measurements we were supposed to keep the mic in the exact same spot? I feel a little dumber every time I log in here....


Moving mic is literally moving the mic around your ears in the listening position. You play mono pink noise and by doing this you’re averaging measurements at all of the positions the mic is in. 


Sent from my iPhone using Tapatalk


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## Mauian (Jul 25, 2019)

This series demonstrates the moving mic technique and is also a good series to pick up some tuning tips from.

Kyle Ragsdale videos:







Sent from my iPhone using Tapatalk


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## RockitFX (Aug 22, 2018)

Thanks guys!
I'll watch the video before I make anymore comments/ask anymore questions. Cheers


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## geolemon (Aug 15, 2005)

Sam Spade said:


> That's one of the best posts ive seen here geolemon. On a similar note in a PM i asked "But i wonder since DSPs are so important in cars is it best to get a really good dsp and build your system around it or is it better to build the system then add the dsp? "
> 
> Whats even harder is once the signal processing is done a dsp back end is basically a DAC and preamp. And a chunk of carfi people seem to not realise how fundamenally important that is. And how the hell do you AB that? Thats the stuff homefi people agonise over in ab comparisons to match their speakers.
> 
> ...


Thanks.
In all the years I went to CES, the best time - the most valuable time - was spent at the high-end audio section. You can't do better for training a "tuned ear" than walking from one vendor room to another to another to another... One ludicrous $300,000 system to a $200,000 system to a $400,000 system... And possibly a $4,000 system here and there playing David among Goliaths.

Personally, I'm of the mindset that even in HOME audio, solid silver speaker wire, $12,000 signal cables - it's unnecessary.
And I'm someone who WILL use the Fractal Analogy to defend analog over digital.
Cars have a pretty big noise floor - so do houses, really.
I'm laying in my living room on the sofa right now - my AC just cycled off making it quiet enough that I can hear... The refrigerator running. The constant electrical buzz of my cable box that you tune out unless you listen for it. There's always something.

But I'm with you on the point about a DSP needing to subsequently have a good DAC on board. That's a great point, really.

It gets back to my point on comparing DSP units...
It's like comparing computer processors, or video cards. There should be benchmark tests that can be run (speakers - we Klippel, or Dumax), so you can compare.
If not? That guy you trusted - he doesn't know either. How can he? It's 8 or 12 or 15 stages of circuits and processing, electrically or digitally - and he's going to know it's "the DAC in this one isn't as good as that one"?
Sure - if one is 1gHz and the other runs at 2gHz, the second faster one might be objectively better. If the noise floor on one is -120dB, that's better than -95dB on the other one.
This information should be available, should be able to be used to compare.

Imagine if you were shopping for cars, and no one published specs - no hp, no mpg, to cornering, no details on that interior, the stereo, the reliability...
And you had to buy a car by trusting people on the internet who claimed they'd used this one or that one...
Or that other guy who claimed he'd used LOTS of them (not suspicious at all!). Or the dealer, who at least can give you a demo but certainly not an unbiased opinion.

I feel like these should be able to be compared better.

Sent from my LM-G710 using Tapatalk


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## Sam Spade (Mar 16, 2020)

geolemon said:


> Thanks.
> In all the years I went to CES, the best time - the most valuable time - was spent at the high-end audio section. You can't do better for training a "tuned ear" than walking from one vendor room to another to another to another... One ludicrous $300,000 system to a $200,000 system to a $400,000 system... And possibly a $4,000 system here and there playing David among Goliaths.
> 
> Personally, I'm of the mindset that even in HOME audio, solid silver speaker wire, $12,000 signal cables - it's unnecessary.
> ...


Hi geolemon

Absolutely agree hi end shows are fantastic. When I was working in hifi at uni I also got to mess around with some amazing stuff. We had one of 5 Marantz CD12 DA12 that came into Australia, Marantz CD12 and a PM95 Marantz PM-95. A $10k nakamichi pre power and top end Luxman. Top end Dali and spendor loudspeakers. And I was mucking around with this stuff as a 22 YO. 

Solid silver, even silver coated wires are nonsense I reckon. They've been dismissed in double blind randomised trials from memory. We should look to Pro gear more. If that audiophile unicorn turd stuff really works the pros would be using it. I have Mogami studio gold balanced XLR's in my home system and you can get stage gold versions that are a bit more robust. At a fraction of the cost of audiophile cables and probably better made. 

You don't just need a good DAC, it needs to be implemented well. The SABRE32/ESS9038Q2M DACs in my burson preamp.dac can be really bright and harsh if they aren't implemented right. And the analogue output stage is critical too. Solid state op amps or proper values, not IC's. 

A checklist of features would be great and a list of specs, to help comparisons. The guy I trusted, I think he's building a home system based around an Ultra including his own speakers from the ground up probably using brax drivers, and he constantly talks to AF engineers and tells me what products to buy and what not to buy in his range so I trust him. It's a bit like SkizeR, some people seem to know what they are talking about. Although everyone has their own biases. 

cheers
Sam


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## Truthunter (Jun 15, 2015)

Sam Spade said:


> Hi truthhunter
> 
> " which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). "
> 
> ...


Please read the link … Beyond frequency amplitude/phase correction it explains the goal of Dirac to correct the Impulse Response of the room in the time domain.


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## Truthunter (Jun 15, 2015)

opekone said:


> According to the link it's using 9 different mic positions and an impulse response and with that the software can build a very comprehensive model of phasing. If it works half as well as it should... well then. If you have the top end version of smaart they have plugins that will do this for you. Once you have the data from multiple mics in at multiple locations then writing a match algorithm probably isn't really the hard part. In smaaart you run your mics concurrently, but it looks like dirac asks you to repeat the measurements with new mic positions and then internally overlays the impulse responses?
> 
> Who has experience with it? How new is this tech? Is it winning SQ competitions?


Many on here have been using it for a while. A little search on here will turn up many threads and reviews. Dirac Live was only available on high end home processors before it became available for 12v through MiniDSP in early 2019. It's also now available for pro and studio applications too.

As for if it's winning SQ comps - Yes & No... doesn't really mean anything IME.


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## Sam Spade (Mar 16, 2020)

Truthunter said:


> Please read the link … Beyond frequency amplitude/phase correction it explains the goal of Dirac to correct the Impulse Response of the room in the time domain.


ok thanks will do


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## Truthunter (Jun 15, 2015)

opekone said:


> According to the link it's using 9 different mic positions and an impulse response and with that the software can build a very comprehensive model of phasing. If it works half as well as it should... well then. If you have the top end version of smaart they have plugins that will do this for you. Once you have the data from multiple mics in at multiple locations then writing a match algorithm probably isn't really the hard part.


I think this line on their tech info page is what set's Dirac Live apart from what can be accomplished with the smart plug-ins:

"Using a look-ahead buffer enables impulse response correction"

Best I can imagine is that it's looking ahead at the input signal and modifying it in real time to correct for the room IR... hence the 13.8ms latency.


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## geolemon (Aug 15, 2005)

Truthunter said:


> Just thought this thread needed some more info:
> 
> The MiniDSP 8x12DL does not allow the tuner to manually set up FIR filters. Dirac is an algorithm licensed from Dirac Research which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). It is not (just) an auto eq like what has been and is offered in some headunits and conventional standalone DSPs based off an RTA and should not be compared to those as such. It's also not (just) an auto amplitude & phase eq either. And it is not "just push the easy button and now you have a optimum tune" like I have seen some refer to it as.
> 
> ...


The Dirac link is helpful, it seems they maybe don't really use an FIR (or IIR) filter at all, but rather a proprietary one that aims to do what an FIR filter can do, at lower processing speeds.

Now, I've never used Dirac, but I've had a Sony 5.1 DVD home theater system that had a room correction mic, and it was pretty remarkable. In that case, I don't believe it actually did ANY EQ at all, it was just measuring bursts of pink noise to identify speaker distance and adjust time alignment and overall level. And sure enough - it balanced everything.

Now - the actual concern, for a DSP unit that's not cheap, and unlike a Sony 5.1 home theater box set - one that's supposed to support more than one use case:
I'd love a feature like this - I'm not sure I want to pay an extra $300 for it, but part of that includes the mic that I need regardless...

What I want to know is not even with regard to a specific filter... I want to know about the feature. Do you know if you can use Dirac on some channels, but not on others?
In my case, I would LOVE to use Dirac on my front stage, and really even could use it on the midbass support on the rear doors, to bring them in alignment with my front door midbass.
...however...
I want two channels for differential rear fill. That means not only creating the L-(L+R) and R-(L-R), but also adding delay to intentionally bring them OUT of alignment with the front stage.

I definitely don't want to spend an extra $300 to PREVENT me from doing that. Is that what you are saying?


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## geolemon (Aug 15, 2005)

Truthunter said:


> I think this line on their tech info page is what set's Dirac Live apart from what can be accomplished with the smart plug-ins:
> 
> "Using a look-ahead buffer enables impulse response correction"
> 
> Best I can imagine is that it's looking ahead at the input signal and modifying it in real time to correct for the room IR... hence the 13.8ms latency.


Honestly, I think that "look-ahead" and "improve impulse response" are just marketing-speak to make something sound fancier than it is.

Any time-alignment involves delaying some of the channels - the DSP doesn't release the signal to the amps until the non-delayed portion of the signal arrives in the signal path. So, effectively the DSP has "looked ahead" down the signal chain by some amount, and processed some of the signal, before it actually released it in it's adjusted/combined form, to the amps. 
But doesn't "look ahead" sound like the unit has some sort of extra-sensory perception? The ability to predict the future? Electronic wizardry? 

Same with "improving impulse response". Think of a worst-case scenario - an install with 12 speakers and each is a different distance from your listening position. Each impulse or burst of sound in your music will arrive at a different time, which can have a bit of a blurring effect if the difference is extreme enough. When you use the DSP to time align the 12 speakers for your listening position, then the speakers all produce sound at a different time to allow them to arrive at your listening position at the same time, "improving impulse response"... really "improving impulse arrival".

Marketing. Like always, it helps to interpret it, I think.


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## opekone (Mar 24, 2020)

geolemon said:


> Honestly, I think that "look-ahead" and "improve impulse response" are just marketing-speak to make something sound fancier than it is.
> 
> Any time-alignment involves delaying some of the channels - the DSP doesn't release the signal to the amps until the non-delayed portion of the signal arrives in the signal path. So, effectively the DSP has "looked ahead" down the signal chain by some amount, and processed some of the signal, before it actually released it in it's adjusted/combined form, to the amps.
> But doesn't "look ahead" sound like the unit has some sort of extra-sensory perception? The ability to predict the future? Electronic wizardry?
> ...



As a cynic, I appreciate your cynisism.

But you seem to think correcting the impulse response means time delay, it does not. It's a mix of time delay, frequency based phasing, and EQ (though they suggest there are limits to the usefullness of EQ here). There could be more I don't know about, as I have not studied this in a structured or rigorous environment. I know that we are familiar with being good at stuff, but I promise a computer comparing 9 data sources can do more to interpret that data and match it to whatever you want than the best of our brains. If you can do better than smaart without using any of the expensive equipment I'm sure you can make a lot of money as a live sound engineer.


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## geolemon (Aug 15, 2005)

opekone said:


> As a cynic, I appreciate your cynisism.
> 
> But you seem to think correcting the impulse response means time delay, it does not. It's a mix of time delay, frequency based phasing, and EQ (though they suggest there are limits to the usefullness of EQ here). There could be more I don't know about, as I have not studied this in a structured or rigorous environment. I know that we are familiar with being good at stuff, but I promise a computer comparing 9 data sources can do more to interpret that data and match it to whatever you want than the best of our brains. If you can do better than smaart without using any of the expensive equipment I'm sure you can make a lot of money as a live sound engineer.


I'm retired from audio work. 100% of my focus in audio these days is solely for myself. Back to being a hobby. It's a good place to be, finally.  

Time alignment IS part of the equation. My point is that unit is aligning multiple sources to the received [and perceived] the same, at a listening position of concern. That's where the mic is (was). An impulse is just a piece of the signal at a moment of time that is being compared at the listening position.

My description of the Sony unit was just a cheap example, I was just describing in that specific case, all it did was time alignment and level adjustment. Maybe it actually did more, but I believe that's all it did. Even in that cheap implementation, the results were pretty good. And in that case, there WAS no "manual" option. Your only tweakability was to move the mic and try again.

When you say "frequency based phasing", I think you mean "frequency based delay". Yes, there are frequency-based phase effects when you have crossovers and EQ and filters - I'm confident you know that's "the" big reason to avoid big EQ cuts/boosts and careful selection of crossover slope types, avoiding odd-order crossovers without a specific need that justifies it... so pocket those kinds of frequency-based phase-shift issues for a moment:
When I think of phasing, I think of the very binary 0/180 phase flipping meant to try to mitigate some of that stuff, or else to create differential signals.
When I think of delay, I think of the normal usage, to shift an image around. 
And since this is marketing material, I believe that's how they intend it here also.

Trust me, I'm not saying frequency-based delay doesn't make intuitive sense - it surely could be used to directly counteract some of those filtering/EQing phase shifts that are frequency-based, if that is what you mean. That would be something. It's just not clear if the Dirac even does that. Interpreting the marketing, they use very time-specific terminology, and then a pretty nebulous "spectral" term, which usually means "frequency spectrum"... especially when they open the paragraph with "Why does the same frequency spectrum sound different from room to room?", we have to make that association. Many of us DO understand from a room-gain and acoustics perspective - of course if you carried speakers around from room to room, why they would sound different, and to that end- we can even simulate different types of rooms using _nothing _but EQ curves. It's really what old-school DSP from the past couple decades did - and that's it.
So my takeaway from the "Frequency Response" paragraph is that Diract uses a mic at the listening position to do both time alignment (delay) and frequency alignment (EQ).

If it actually does correction for the discrete phase shifts caused by each EQ and filter, that would be very impressive - that would be "frequency-based phasing". It's possible that it actually does that, but for marketing purposes they've dumbed-down this description for broader consumption. They do differentiate "linear phase" from "minimal phase" which are already terms deep into the signal-processing math major's term paper, so I was assuming they meant that more colloquial sense here in the context of a marketing material... the first signal arrival.

For the "Impulse Response" paragraph though, this is exactly what I'm saying - alignment makes the attack and decay match the signal, where if they are time shifted it causes that "blurring" effect - even echo, if shifted to an extreme. But that's not what you are saying, correct?


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## geolemon (Aug 15, 2005)

And that doesn't change my desire to create an L-(L+R) and R-(L+R) with an intentionally delay to simulate rear-reflections without causing phase issues....
Which is actually something that the old-school DSPs could do also (so they weren't all purely EQ-based, now that I think of that - like "concert hall" settings).

I'd be pretty bummed if I paid $300 extra for this DSP and found that the use of Dirac was mutually exclusive with my ability to create those delayed differential-only outputs.

It would actually be my deciding factor - I was considering both the 8x12 and 8x12DL, leaning towards the 8x12 because I don't mind the extra time it would take to tweak/tune (different story if it wasn't for my own personal ride), but I'd definitely lean towards the 8x12DL if it truly does those phase-based compensations for filtering done in every other logical section of the DSP... as long as I can still spin up my delayed differential channels, that is. 

To be fair, I could also add a 2x4 just to do the delay for those channels, but I'd rather have it all in one unit.


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## Truthunter (Jun 15, 2015)

geolemon said:


> The Dirac link is helpful, it seems they maybe don't really use an FIR (or IIR) filter at all, but rather a proprietary one that aims to do what an FIR filter can do, at lower processing speeds.


The way I understand it is that it utilizes IIR where FIR is not required, and use FIR where IIR doesn't achieve the result. Doing so instead of just using FIR all around conserves processing.



geolemon said:


> Now, I've never used Dirac, but I've had a Sony 5.1 DVD home theater system that had a room correction mic, and it was pretty remarkable. In that case, I don't believe it actually did ANY EQ at all, it was just measuring bursts of pink noise to identify speaker distance and adjust time alignment and overall level. And sure enough - it balanced everything.
> 
> Now - the actual concern, for a DSP unit that's not cheap, and unlike a Sony 5.1 home theater box set - one that's supposed to support more than one use case:
> I'd love a feature like this - I'm not sure I want to pay an extra $300 for it, but part of that includes the mic that I need regardless...
> ...


No, it will not prevent you from delaying each output channel as you desire. There is a member here (#Naiku) that had his car set up just like you describe except he did use Dirac on the rear fill also. It has 8ch of Dirac processing but 12 output channels and each output channel has it's own set of conventional DSP adjustments (10band PEQ / APF / Custon Biquad filters, HP/LP/BP @ 6-48 slopes, Levels and Time Delay). So the rear fill can be delayed further as the user sees fit after it's IR is corrected by Dirac.


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## Truthunter (Jun 15, 2015)

geolemon said:


> Honestly, I think that "look-ahead" and "improve impulse response" are just marketing-speak to make something sound fancier than it is.
> 
> Any time-alignment involves delaying some of the channels - the DSP doesn't release the signal to the amps until the non-delayed portion of the signal arrives in the signal path. So, effectively the DSP has "looked ahead" down the signal chain by some amount, and processed some of the signal, before it actually released it in it's adjusted/combined form, to the amps.
> But doesn't "look ahead" sound like the unit has some sort of extra-sensory perception? The ability to predict the future? Electronic wizardry?
> ...


Though it can be set up to automatically provide delay figures for each driver based on IR - Improving the IR is more than just that. It improves the IR of individual channels AND thier relation ship to other channels. It improves the transient attack/decay time which is colored from room resonances. The results are perceivably different than just having time delay appropriately adjusted per channel.

I posted these in one of the Dirac threads on here but here they are again. Really there is a lot of information in those Dirac threads... would likely answer any questions/concerns you have. There are also many other forums with Dirac info as many use it in home theatre and stereo setups.


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## geolemon (Aug 15, 2005)

Thanks - that is helpful.
I'm not opposed to using it on the fill channels, as long as I've got the option available to add delay for the very intentional purpose for ambiance.

I actually ran off and started digging through their documentation, and was encouraged to find these - but I'll check that out. Is that on the miniDSP forum? Or is there a Dirac-specific forum? I haven't joined either since I haven't owned their product [and generally avoid product-biased forums, but would check it out on your recommendation].

From my digging specific to the miniDSP 8x12DL - it does seem to indicate that the Dirac can not only be bypassed per channel, but even if engaged,the processing flow diagram indicates all the manual controls still remain:


















Encouraging.


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## opekone (Mar 24, 2020)

geolemon said:


> I'm retired from audio work. 100% of my focus in audio these days is solely for myself. Back to being a hobby. It's a good place to be, finally.
> 
> Time alignment IS part of the equation. My point is that unit is aligning multiple sources to the received [and perceived] the same, at a listening position of concern. That's where the mic is (was). An impulse is just a piece of the signal at a moment of time that is being compared at the listening position.
> 
> ...


Surely the whole point of 9 listening positions and the hybrid IIR FIR approach is to do exactly that. I mean like I said smaart does this, I'm sure there are other suites out there that do this. I'm sure a few dozen sound engineers have written their own algorithm.

As for my understanding of frequency based phasing, vs. delay, vs. allpass... This is really getting to the limits of my understanding of these systems. As I understand it phase rotations don't effect delay in the sense that an impulse response is going to arrive at the same time no matter what it's phasing is, but at the same time an allpass filter applies localized delay based on frequency and some other parameters. So we are applying delay to the signal in a way which conserves the impulse response. I can't quite wrap my head around that.

But my brain is not a limit for anyone but me, thankfully.  And I expect this is exactly the point of dirac.


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## geolemon (Aug 15, 2005)

For sure! It's remarkable how simple ANY of the auto-tune systems make it. Mind blowing.

And yes - that's all an all pass filter does is phase to coordinate with a crossover frequency, so I think I see where you are coming from... And yeah, that's basically what I'm saying too - essentially I thought you were saying Dirac has more or less a huge bank of parametric all-pass filters, if you will, to deploy as it automatically identifies phase issues. That would be something.

I'd love to know how if it actually does that - it doesn't sound impossible. 

Sent from my LM-G710 using Tapatalk


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## geolemon (Aug 15, 2005)

So regardless of that minor detail-

If you option up a miniDSP 8x12 with a mic, and an 8x12DL that inherently includes a mic...
It's about a $325 price difference I believe.

The question is... Is the Dirac factor worth it?

I say that as someone who is intrigued, but did not have any auto-tune or even auto-effect on my list of requirements. Really I need an 11-channel unit that allows me to filter, EQ, delay, and create my differential ambient rear channels with a mixer...
And since I longer have access to the old Audiocontrol RTA (and man that seems stone-age primitive these days anyway), the RTA factor.

So from the standpoint of what I originally set out to buy - Dirac would be a $325 impulse buy.

So tell me - the inevitably obsessive ever-tweaker - can you think of any scenarios where a person might truly regret getting the Dirac version?
I'm still unclear if it's essentially an auto-tune to speed initial tuning.., or if it does deploy [effectively] a big parametric EQ worth of all-pass filters that smooths phase (or any effect) that has no manual-tweak equivalent (quality-of-result notwithstanding)?


Sent from my LM-G710 using Tapatalk


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## opekone (Mar 24, 2020)

geolemon said:


> For sure! It's remarkable how simple ANY of the auto-tune systems make it. Mind blowing.
> 
> And yes - that's all an all pass filter does is phase to coordinate with a crossover frequency, so I think I see where you are coming from... And yeah, that's basically what I'm saying too - essentially I thought you were saying Dirac has more or less a huge bank of parametric all-pass filters, if you will, to deploy as it automatically identifies phase issues. That would be something.
> 
> ...


Again, this is my understanding, but that is what it does. AFAIK the phase response you measure at any one point is going to have a lot of noise and only some of the phasing information is meaningful. When you can compare the response in 9 locations you can build a model of the phase response and pull out the noise so you're not just trying to match a single noisy measurement to a curve. From there you see the match algorithm is trivial.

Now I know there are dozens of far smarter people than I on this forum. Some of them have to understand what's going on inside here.


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## opekone (Mar 24, 2020)

geolemon said:


> So tell me - the inevitably obsessive ever-tweaker - can you think of any scenarios where a person might truly regret getting the Dirac version?
> I'm still unclear if it's essentially an auto-tune to speed initial tuning.., or if it does deploy [effectively] a big parametric EQ worth of all-pass filters that smooths phase (or any effect) that has no manual-tweak equivalent (quality-of-result notwithstanding)?


That would be a great email to CS or to a live chat person if that do that on minidsp's website. I'm sure you'll get a succinct response.


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## opekone (Mar 24, 2020)

From MiniDSP's blog. 








Room correction improves on room EQ to deliver unrivaled audio optimization - Dirac


By Niklas Thorin, Dirac General Manager of High Performance Audio Recent advances pioneered by leading technology companies are changing how audiophiles and general home theater...




live.dirac.com




I also shot them an email hoping for a better explanation, but this one is pretty good.




> Recent advances pioneered by leading technology companies are changing how audiophiles and general home theater enthusiasts approach audio performance in their homes. While frequency equalization provides a degree of control over sound characteristics, and room EQ solves some issues with reverberations and frequency response, a far more robust and effective solution’s penetrating the market and delivering truly optimized listening experiences for any listening environment: room correction.
> 
> 
> *What’s wrong with the room?*
> ...


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## Mauian (Jul 25, 2019)

This is a nice review by Erin of the mini dsp with Dirac. He falls into the camp of someone who is always tweaking his system (and loves to do it) and is skeptical of anything that is auto-EQ, but came away quite impressed. He does talk about the limitations though (like if you setup your sub out of phase with your mid bass it can’t fix that). I haven’t finished reading it but here it is:







MiniDSP C-DSP 8x12 with Dirac Live Review


MiniDSP C-DSP 8x12 with Dirac Live




www.erinsaudiocorner.com






Sent from my iPhone using Tapatalk


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## Mauian (Jul 25, 2019)

I like the last paragraph of his review:

“I am continually asked about this review: “should I get this or the Helix (enter DSP model here)?” I expected I would. But I purposely left out a comparison in my review simply because you’re comparing apples and oranges to a large degree. On its own the miniDSP CDSP 8x12 has less features than the Helix models. The miniDSP also costs less. However, as I state in the review, my focus is on the combination of the CDSP+Dirac Live. In that regard, you’re essentially comparing two different products: a manual tuning product (Helix, etc) vs a mostly-automated tuning product (Dirac). If your question is “which one should I buy”, then I’ll answer you with a question: “How good a tuner are you?” If you fancy your own prowess in tuning then manually controlling everything may be better for you. If you don’t, I think the miniDSP is a great product and absolutely worth consideration.”


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## Truthunter (Jun 15, 2015)

The nice thing about the standard CDSP 8x12 V2 is that it can be upgraded to the DL version with just a firmware update. So one can play with it for a while and if they have the urge to try Dirac later... It's an easy upgrade.

As far as someone who likes to tweak... That's me too. There are many ways that the Dirac Live processing can be implemented. Most are using it as 2ch L/R but it could be used as multi-channel. Then there is all of the manual tuning abilities that can be played with. One example for instance is does doing a full pre-tune on each individual driver and then running Dirac result in better sound then just letting Dirac do all of the EQ/delay? Also, mic positions can be experimented with... I seem to get the best results with mic positions within 4 in of my ears... but others I know prefer the results with more distant mic positions. I think each vehicle is different and different combinations of implementation may work better for some than others. There really are many different ways to use this thing that can be experimented with.

I found this video to be easy to understand and informative about the tech:


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## geolemon (Aug 15, 2005)

Thanks, Opekone, Mauian, and Truthunter- you guys are all awesome.
I'm definitely going to check out those videos this afternoon. It's a little tougher since I'm working from home these days and don't have dual monitors like I have at the office, but I might just pull them up on my phone in a dock under my screen. Lots to check out - thanks, very much appreciated.


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## geolemon (Aug 15, 2005)

Mauian said:


> I like the last paragraph of his review:
> 
> “I am continually asked about this review: “should I get this or the Helix (enter DSP model here)?” I expected I would. But I purposely left out a comparison in my review simply because you’re comparing apples and oranges to a large degree. On its own the miniDSP CDSP 8x12 has less features than the Helix models. The miniDSP also costs less. However, as I state in the review, my focus is on the combination of the CDSP+Dirac Live. In that regard, you’re essentially comparing two different products: a manual tuning product (Helix, etc) vs a mostly-automated tuning product (Dirac). If your question is “which one should I buy”, then I’ll answer you with a question: “How good a tuner are you?” If you fancy your own prowess in tuning then manually controlling everything may be better for you. If you don’t, I think the miniDSP is a great product and absolutely worth consideration.”
> 
> ...


Essentially yes - this is my dilemma.

You have to count me as an exception, as more of an audio geek than an audiophile even. Or at least equal parts. One reason I do want this DSP with so many channels active, is to turn all the knobs, if you will... to further develop my own tuning capabilities and experience. With the old school tools, EQ, and even older, more primitive DSPs, there just wasn't this much control. So the good news is - I have lots of the old tricks for working around certain issues that today's DSPs allow you to resolve directly. And that's where I'd like to start my exploration.
So, I'd say "expanding my tuning skills" is even a higher goal than "achieving good sound", to me personally. Exploring the equivalents - the old way, vs the new way. For sure I'll have equal parts "degrading my sound" and "improving my sound". How awesome is it to be able to save a tune and quickly revert back to it after you screwed everything up? To me, that's fun - expanding knowledge on sound and manipulation.

And as I've already beaten to death - the pursuit of that imaging that I've only experienced at the high-end audio section of CES shows, but I still believe is possible in a car - including stage width and depth. Phase-perfect sound is one of those things that definitely influences the psychoacoustics that impact imaging just as much as amplitude EQ. So from that perspective, a $325 investment in a module that might help tune one aspect that's otherwise invisible (other than nulls!) and difficult to tune... it's intriguing.

But back to the flip side - I like my personally unique tricks and techniques to produce the wow factor. I may be 46, but I grew up skateboarding, and from that I learned two things:
1) it's fun to pull off a trick no one has seen before, no one expects to even be possible - and then you do it. That really 
2) On a skateboard, there's a big difference between landing sketchy and barely rolling away, and refining it and training yourself until it looks effortless.

I say that as an analogy on both fronts, since growing up with that passion obviously shapes my mentality about this one as well:
-- 1. No one should be impressed by a novice getting on a skateboard, stepping off, pressing a button marked "auto", having the board automatically flip itself, and jumping back on.
-- 2. If my results I have today aren't good enough - I'm fine with taking the time, over time, to continually evolve my installation, and my tune, as my personal achievement.

So I'm betting seeing these videos should help me understand if there's actually a holy-grail phase-correction tool unlocked here for a mere $325, or if it's mostly automation of some otherwise-existing capabilities the base 8x12 (or Helix Ultra) have. So thanks again.


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## opekone (Mar 24, 2020)

geolemon said:


> So I'm betting seeing these videos should help me understand if there's actually a holy-grail phase-correction tool unlocked here for a mere $325, or if it's mostly automation of some otherwise-existing capabilities the base 8x12 (or Helix Ultra) have. So thanks again.


I mean if it does everything it's supposed to do it's just an REW style EQ for phasing. It's not going to fix everything, but who in their right mind ignores REW?


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## Holmz (Jul 12, 2017)

Truthunter said:


> Just thought this thread needed some more info:
> 
> The MiniDSP 8x12DL does not allow the tuner to manually set up FIR filters. Dirac is an algorithm licensed from Dirac Research which utilizes FIR & IIR automatically to achieve room correction results (notice I did not say frequency response correction). It is not (just) an auto eq like what has been and is offered in some headunits and conventional standalone DSPs based off an RTA and should not be compared to those as such. It's also not (just) an auto amplitude & phase eq either. And it is not "just push the easy button and now you have a optimum tune" like I have seen some refer to it as.
> 
> ...


I believe that there is also the French Waveflex DSP.

It is also my understanding that MiniDSP can neither support uploading nor downloading the FIR taps.

And there is a company's in Sydney that has the S/W to generate the FIR taps.
However that may not be needed except for using the Waveflex unit??

The questions that probably comes first are:

What does all that do?
Does one need to do it?
Can one do the same general thing with an All-Pass filter?
Only when we are talking about correcting impulse response, or group delay, is when a FIR is needed.
Whether one needs to do that depends on how much group delay is present, and how the impulse response looks, and how well one wants those to look.

Since the OP is running powered subs, we can probably scratch GD off the needs category, as their GD has not given the OP any listening complaints.



Truthunter said:


> Though it can be set up to automatically provide delay figures for each driver based on IR - Improving the IR is more than just that. It improves the IR of individual channels AND thier relation ship to other channels. It improves the transient attack/decay time which is colored from room resonances. The results are perceivably different than just having time delay appropriately adjusted per channel.
> ...


As a side note, only five home system seem to intentionally optimise for impulse response.
So if one has one of those five, then they may not see a great improvement from very good to a bit better.

And few speaker manufacturers show impulse response plots.
Measuring the impulse response would be one way to understand whether it seems bad enough to take the time to improve... but most people also say that DIRAC live sounds better, so some dodgy empirical evidence exists... and the various impulse plots like DIRAC at least tell us why.
(Which is hugely different than things like testimonies on $1000 RCA cables... and we can see before and after.)




geolemon said:


> Essentially yes - this is my dilemma.
> 
> You have to count me as an exception, as more of an audio geek than an audiophile even..
> ...
> ...


Do you want DIRAC as an auto tune, or do the DIRAC manually?
The former is MiniDSP, the later approach would be to use a different FIR DSP.


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## geolemon (Aug 15, 2005)

Holmz said:


> Do you want DIRAC as an auto tune, or do the DIRAC manually?
> The former is MiniDSP, the later approach would be to use a different FIR DSP.


Well again - frequency-based phase compensation wasn't even on my list, so to me that's the differentiating factor.
As for an "auto" feature... as long as it doesn't preclude manual tuning, then it's a bonus, rather than a deal-breaker.

But I'm also reading up on rePhase now. Looks like that might provide a non-Dirac option for frequency-based phase compensation that lets you export biquads to program into the standard C-DSP 8x12. 
Since I could always upgrade that down the road to add Dirac if I regretted not having Dirac, I'm not high and dry without it - that's actually a cool option, and let's see how high the price of regret is:

*C-DSP 8x12 DL*​C-DSP 8-12 upgraded to Dirac​*DSP*$ 899$ 499*Mic*included$ 75*Dirac upgrade*included$ 329*TOTAL**$ 899**$ 903*

Check my math on that but... am I right? Only a $4 penalty for not buying the DL version up-front? 
I think that makes the choice obvious...  that doesn't seem right, even...


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## fatstrat (Jul 12, 2019)

jtrosky said:


> You can do time alignment right away. Usually, I think people do levels, then time-alignment - but could do time-alignment first if you wanted. Target curve is mainly achieved via EQ, not time-alignment (although time-alignment can impact the frequency response as well, which is why it's usually set before EQ). There are some people talking about ways to figure out time alignment with REW on the "other" forum right now, but not sure how reliable it is. Just using tape-measure measurements is the most common way to set initial time-alignment. You can fine-tune later if needed.
> 
> Hope that helps. Anyone - feel free to correct me if I mis-stated anything.


What other forum. I'd like to check it out?


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## jtrosky (Jul 19, 2019)

fatstrat said:


> What other forum. I'd like to check it out?




```
www.caraudiojunkies.com
```


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## fatstrat (Jul 12, 2019)

jtrosky said:


> ```
> www.caraudiojunkies.com
> ```


That's what I thought.


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## Holmz (Jul 12, 2017)

geolemon said:


> Well again - frequency-based phase compensation wasn't even on my list, so to me that's the differentiating factor.
> ...


Frequency or phase?
Or both?




geolemon said:


> ...
> As for an "auto" feature... as long as it doesn't preclude manual tuning, then it's a bonus, rather than a deal-breaker.
> ...


If you cannot get taps out, and then other taps back in... then that would preclude "manual tuning" to an some extent (IMO).




geolemon said:


> ...
> But I'm also reading up on rePhase now. Looks like that might provide a non-Dirac option for frequency-based phase compensation that lets you export biquads to program into the standard C-DSP 8x12.
> ...


The biquads are an IIR thing, so you one can get there to a new extent for maybe group delay.
I am not sure if one can get there for impulse response correction though.

In my mind we first figure out we want to compensate or equalise, an maybe some graphs to know that we need too.
Then we determine whether we need FIR, or whether IIR will get us there.

The MiniDSP will not allow one to get to the taps, but it will probably auto them better most can do manually.

Have you looked at the other two options(?), and know how to compare those to the 8x12?


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## geolemon (Aug 15, 2005)

Holmz said:


> Frequency or phase?
> Or both?


Phase was always on my checklist... But really only for something my old-school self never tried before - differential ambient rear fill channels. So, phase and mixing, to create L-(L+R) and R-(L+R).

I also checked out a few of the Facebook channel videos the Mosconi engineer put up there... It's amazing how GOOD they are, how detailed, for how absent and terrible DSP documentation is on Gladen/Mosconi's web site. I only mention that, because he mentions a proprietary rear fill filter meant to serve an entire different purpose than the live rear ambiance I am imagining... His is engineered to widen rear fill. So I imagine trying to replicate something like that with my rear fill channels would also be something fun to experiment with them, and I imagine would be derived in at least a similar way (Phase, combine, delay).

Now - I'm old school. It's not that I haven't noticed the mid-band imaging impacts, I just always assumed they'd be unavoidable, passive or active. In fact - for decades I'd long advocated using supplied passive Xovers OVER the old-school non-DSP methods of going all-active, primarily to minimize those phase issues to the best of the crossover's design... which varies from comp set to comp set but is a damn sight better than Joe Driveway with two filter knobs on two amps, thinking he's got them aligned. Clearly a DSP gets you past that... 
...but I'm surprised these little boxes have the computing power to make this level of dynamic delay to compensate for Xover phase issues a possibility. 




Holmz said:


> If you cannot get taps out, and then other taps back in... then that would preclude "manual tuning" to an some extent (IMO).


True. 
But if Plan A was to find a DSP to buy that didn't touch this feature...
And Plan B is an option that adds it, without impacting the other Plan A features, except the dynamic phase corrections are automatic - that's still a plus.

Reading up on Plan C - rePhase with the Biquads, which is more like I HAD figured something like this would be implemented in a more manual/cryptic/oldschool way. I personally think I'd learn more, this route, so that's good ... and pretty cool that I could add Dirac at basically no penalty. Less than a couple Red Bulls.




Holmz said:


> The biquads are an IIR thing, so you one can get there to a new extent for maybe group delay.
> I am not sure if one can get there for impulse response correction though.
> 
> In my mind we first figure out we want to compensate or equalise, an maybe some graphs to know that we need too.
> ...


I thought the FIR were needed for this level of phase adjustment... and sounded (at least from Dirac marketing) like it takes some processor horsepower - but I thought that was to run dynamic, but perhaps Dirac doesn't truly do that either. The biquads would seem to remove the dynamic aspect, so I'm not sure yet what filters the biquads use.

I've been working on my other car while we actually had some outdoor weather -








...so have only still taken a scan at the RePhase docs. Have you ever checked it out?

And actually - what's option 2?

Sent from my LM-G710 using Tapatalk


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## Holmz (Jul 12, 2017)

Your plan A and B differ from my lexicon.

For me a plan 0 is an IIR based DSP.
(Like a Helix)
Biquads are used exclusively with IIR.

A plan 1 would be a FIR, which allows DIRAC or Dirac like processing.
(And I only know of three manufactures units in this domain.)

(IMO) There would be no (or little) reason to worry about phase on a some rear fill channel.




geolemon said:


> ...
> ... for how absent and terrible DSP documentation is on Gladen/Mosconi's web site.
> ...
> thought the FIR were needed for this level of phase adjustment... and sounded (at least from Dirac marketing) like it takes some processor horsepower - but I thought that was to run dynamic, but perhaps Dirac doesn't truly do that either. The biquads would seem to remove the *dynamic aspect*, so I'm not sure yet what filters the biquads use.
> ...


I am not sure what the "dynamic aspect" means in your context above, but the impulse response correction needs a FIR.

If i was designing a home system, I would either be looking at speakers with good impulse response and using 12 dB crossover (XO) slopes.
Or I would be looking for speakers with low distortion and using DIRAC to correct the impulse response.




geolemon said:


> Phase was always on my checklist... But really only for something my old-school self never tried before - differential ambient rear fill channels. So, phase and mixing, to create L-(L+R) and R-(L+R).
> ...


The algebra here suggests we end up with -R and -L?

I could picture a rear fill channel using a FIR bank with some delayed comb.
However one cannot shove that FIR bank into a MiniDSP...


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## geolemon (Aug 15, 2005)

Holmz said:


> Your plan A and B differ from my lexicon.
> 
> For me a plan 0 is an IIR based DSP.
> (Like a Helix)
> ...


As a lifelong IT guy who fell into training from some world class (for the 90's) BI consultants to managing some pretty aggressive ETL schemes to letting that lead me into a deep-dive on database DBMS systems, algorithms, and tweaking SQL and ETL by influencing DBMS and optimizing SQL - I definitely appreciate your 0-index list reference. 

But anyway - I only know of one - just the miniDSP with DIRAC... Curious, what are the other two? Not that i need to make my list of options longer, but... 
I have to say I'm pretty thrilled to discover this is an option, manual or auto.

Maybe there's reasons that Dirac deploys it as auto... but I'm sure you can tell from pretty much anything I ever write, about the way my mind works - if the "auto" option took 10 minutes and gave a superior result, and the "manual" option took 40 hours and an inferior result but gave an understanding of all the underlying mechanisms and theories...
Well, guess which I'd pick. 

I don't believe the Helix have that, which is interesting because in other ways the Helix does seem superior.
Helix is the other one on my list, but I'd have to buy the Helix V12 amp - that makes it pretty cost effective but does lock me into that brand for amp choice as well. I really can't think of a downside to that though.



Holmz said:


> (IMO) There would be no (or little) reason to worry about phase on a some rear fill channel.
> 
> ...
> 
> ...


Right - so for the ambient differential rear fill, to avoid the cancellations with the front stage from multiple pathlengths playing the same signals (imaging killers - comb filter culprits - whatever you want to call it, it's the reason I've always been a "front stage only" purist), you calculate the differential by cancelling out the common stuff. Then you apply a delay, with the intent of simulating the rear reflections at a concert. Front stage stays strong since it's not fighting rear signals, and just the differential comes back since it's the most audible from an ambiance perspective.
I should mention it's also filtered, only like 300hz to 2000hz or so, since that's what reflections come back strongest.
Or so the theory goes - I haven't done it. 

With SQ clients in the past, the only option I had was to filter and delay rears - in fact the Focal TN52's I have came from a rear installation that we ditched the tweeters specifically for that purpose. Win for me... love those tweets.
This DSP gives me the option for the fancy version. Since I"m using my rear doors to try to overcome the midbass nulls (and it would be a terrible location for anything else anyway) I'm even thinking of making tiny pods for 2" located way back in my hatch - but I really haven't given that much thought. I'll find a spot when the time is right.

But yes, you are right - you end up with just distinct L and distinct R, if that's what you meant. Nothing common to both channels. Sounds like it won't be playing much!


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## Holmz (Jul 12, 2017)

I almost always index starting at 1... but sometimes a negative number.
What does the acronym ETL expand to mean?
Is BI, magnetic field * current?
What is DBMS? (I assume it is not DataBase Management System)

Your equation of L -(L+R) =really equals= -R
I think you probably wanted (L-R)/(L+R) or something like that, but I get the idea.

The three FIR based that I know of are alphabetically listed:

APL (does a DIRAC like filter automatically, or one can load the taps manually.)
MiniDSP (some of them are FiR and they have a DIRAC licence, but the taps cannot be retrieved nor loaded)
Waveflex (can do a DIRAC like filter, but I am unclear on much more... as I believed that I would need 3 for a three way,.. and it became a budget driver.). I believe one can load and retrieve the taps.
There may be more now, as my chin scratching was over a year ago.

DIRAC is named after the physicist Paul Dirac, so conceptually it is pretty easy to understand. And it is a great branding name for the Swedish company that makes the S/W and licences it.

Whether that sounds any better in real life than a Helix probably depends on the speakers and the tuner. The theory is solid, but the reality gets muddy when there are other speaker and amplifier distortions, and the acoustic signal is already distorted... or has some minimum level of distortion that one cannot overcome with math.

Some good speakers with 1% THD behind a well setup Helix may have some total distortion of 2% (if we knew how to compute total distortion)
And some bad speakers with 5% distortion, maybe become accoustically 3% once the group delay is removed with DiRAC.

So the 2% is stil better than 3%, and maybe expensive speakers is cheaper overall than a high powered DSP.

But I assume that one would compare the good speakers with a good DSP.


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## geolemon (Aug 15, 2005)

Holmz said:


> I almost always index starting at 1... but sometimes a negative number.
> What does the acronym ETL expand to mean?
> Is BI, magnetic field * current?
> What is DBMS? (I assume it is not DataBase Management System)


it is Database Management System, sad to say. 
It was one hell of an opportunity working with some of the best Business Intelligence consultants in the country, on a data warehousing/data mining implementation project for a GE Capital branch.
It was such an opportunity, I was already deep into electrical engineering... I changed my major to computer information systems, and that coupled with a psychological problem where I have to understand how things work... so that leads nicely into the aspect of a DBA (database administrator) who does the interesting stuff (well, to me) like optimizing queries and ETL.

ETL is Extract/Transform/Load. It's the systems that pull data from a system of record and load it to another system, like a data warehouse. 

The DBMS is a kind of artificial intelligence, though it doesn't evolve. It's a wildly complex algorithm for how the database handles the nearly infinite kinds of requests and tasks database systems need to handle.

I'm sure that's all boring crap to most people - but to me it's another field of study that can be studied. No matter how many times you want to stick your shovel into the dirt, there's always deeper to dig.

Same reason I'm a fan of audio science.



Holmz said:


> Your equation of L -(L+R) =really equals= -R
> I think you probably wanted (L-R)/(L+R) or something like that, but I get the idea.
> 
> The three FIR based that I know of are alphabetically listed:
> ...


I'll check out all three, big thanks for that.
I'm feeling like the miniDSP - I love that I can upgrade it to add the Dirac if I want. 

I've been lucky in all my years at CES sneaking off to the high-end audio section, to hear some of the world's best, cleanest, most accurate systems that hundreds of thousands of dollars can allow a vendor show off the possibilities with. So I'm not needing to try to make my own system reveal perfection to me. I can instead have fun playing and tweaking and exploring, trying to make things without the exotic names perform.

Another analogy-

I wouldn't hate a Lamborghini. But I wouldn't have fun in a Lamborghini once the initial experience was experienced. Why? Because everyone knows you are in a Lamborghini. I didn't build the Lamborghini. I would have just had to have written a big check. All that takes is money, not brains or talent or experience. When you pull up next to any other car - everyone expects the Lamborghini to win. So - if it does, no big deal. If it doesn't - super embarrassing, because that oaf behind the wheel had to be the reason.
On the other hand - if you took a more pedestrian car, took what you worked to learn, and - I don't know, put a Tesla motor in a VW beetle and spanked a Lamborghini some day... the flip is true: If you lined up and lost, no big deal. Expected. If you lined up and won - holy crap, awesome.

So I'm maybe in an odd way also a bit turned off by the idea of having exotic stuff. I'd rather be relatable and helping people do more with less.

And that doesn't mean trying to make crap be unrealistically superhuman. It means (hopefully) knowing enough to know where the point of diminishing returns is, and taking that further. That's the sweet spot.

And someday I'll learn to express these thoughts without so many words... Apologies for the read. 

Sent from my LM-G710 using Tapatalk


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## Holmz (Jul 12, 2017)

The MiniDSP is good for almost everyone.
(I was very close to using the DDRC 88A, it was my pick of the litter from MiniDSP... but it is certainly possible my analysis was somehow flawed.)

If I thought that a MiniDSP was the best for a tinkerer (which you sound like you might be) I may not have mentioned the other two... which are technically better and allow up/down load of the FIR taps.


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## dumdum (Feb 27, 2007)

The issue I see with being a tinkerer is you need some method of measuring the stereo to be able to tinker to the same level as this processor can actually do... I am playing with smaart and rew (and am well versed with both...) plus other bits of software and I won’t pretend to be anywhere near this processors capability’s in the phase and time domain (sorting impulse response is a big thing for me...)


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## geolemon (Aug 15, 2005)

dumdum said:


> The issue I see with being a tinkerer is you need some method of measuring the stereo to be able to tinker to the same level as this processor can actually do... I am playing with smaart and rew (and am well versed with both...) plus other bits of software and I won’t pretend to be anywhere near this processors capability’s in the phase and time domain (sorting impulse response is a big thing for me...)


Absolutely!
Hopefully you are old enough to appreciate that these tools now are so easy and inexpensive...!

If you remember LEAP and LMS, you also remember how big the card was - an IDE card so large, it didn't fit my most recent PC. I need to find a pic... anyone young will laugh. (Found one!)

I kept these manuals in part because that was so expensive in the 90s... Powerful back then (and even into the 00s), but so primitive compared to what we have today.

And have you ever tried to tune using the more common Audiocontrol SA-3055 or 3050? I made that purchase using shop funds... and was blown away by all that power in such a small package... Fits in a backpack-sized case we can bring places!  
Oh and remember you could order it with the blue LED "upgrade"? Cost extra - the shop owner HAD to have that because the other shops didn't... 

I'm not saying tuning is easier today - but the precision AND types of curves you can run today using REW...
Hot damn.
Just that expansion of measurement capabilities is unbelievable...
And at no cost. Just free.
Awesome - literally.
















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## geolemon (Aug 15, 2005)

dumdum said:


> The issue I see with being a tinkerer is you need some method of measuring the stereo to be able to tinker to the same level as this processor can actually do... I am playing with smaart and rew (and am well versed with both...) plus other bits of software and I won’t pretend to be anywhere near this processors capability’s in the phase and time domain (sorting impulse response is a big thing for me...)


And more on point with what you are saying -
There's a thread from @oabeieo on RePhase that's pretty awesome...
I'm looking at it like a "RePhase vs Dirac" but from that thread it looks like you can do both...
Oabeieio was using Dirac as a reference - saved that tune then set off to see if he could beat it - and it seems hard to beat.

But - it's like fixing your house up. 
You could pay extra, fast forward right to the "done" phase...
Or you could DIY, learn, tool-up, and know exactly what's in every aspect of it, plus have pride in what it is.
The easy way out is never satisfying.

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## SiW80 (Mar 13, 2019)

geolemon said:


> And have you ever tried to tune using the more common Audiocontrol SA-3055 or 3050? I made that purchase using shop funds... and was blown away by all that power in such a small package... Fits in a backpack-sized case we can bring places!
> Oh and remember you could order it with the blue LED "upgrade"? Cost extra - the shop owner HAD to have that because the other shops didn't...
> 
> Sent from my LM-G710 using Tapatalk


Used to love my 3050 - even made an exact IASCA spec mic stand so I knew I would get max RTA points at judging 

It almost seems you can tinker too much these days. Certainly more scientific and analytical. 

Used to use the RTA for 80% of the setup and then fine tune with ears. 

Had to write the RTA curve in Word or Excel as I didn’t have the printer. None of this tuning from your laptop. Even the DSP setup was manual!


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## geolemon (Aug 15, 2005)

Yes - and it's unbelievable to me that you can "RePhase" like a parametric EQ of phase.
Before that all I knew was creating an all-pass filter of the passive (and very non-adjustable) kind.
It's like a new world...

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## Holmz (Jul 12, 2017)

geolemon said:


> Yes - and it's unbelievable to me that you can "RePhase" like a parametric EQ of phase.
> Before that all I knew was creating an all-pass filter of the passive (and very non-adjustable) kind.
> It's like a new world...


One can usually do the same thing with IIR as FIR, just with IIR one needs a stack of chained biquads, whereas with FIR it is a single inverse FFT... which makes automatically tuning a bit easier with a FIR.


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## Mauian (Jul 25, 2019)

Dumb question, but can you use Dirac to do a good two seat tune? It seems like you have to pick your measurement locations and then let it do its thing. How would this be done for a two seat tune?


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