# DIY DSP



## gunn234 (Feb 27, 2007)

Hi,

This is something I stumbled upon as great interest.

MiniDSP

They have some people tinkering with these boards in the home with some projects, but so far, there are no takers in the car audio circles. These processers have community based plug-ins that have unlimited possiblities. graphic EQs, parametric EQs, time delay, crossovers of all types, digital limiters, sound processing of any kind.

It seems like an elegant solution as you can use any head unit with a digital output and use a 10k potentiameter to adjust volume in the digital domain. They even have amps that take digital in so you have everything digital all the way to the final output. Even though the amps are of low wattage, you can mix this system with analog input amps for more power. 

Thinking to use the digital amps for sensitive mids and highs. Analog high wattage amps for the midbass and subs.

All additions of software plugins and adjustments done by USB. 

The prices seem so reasonable compared to a lot of the big box solutions out there.


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## davidfrosch (Jun 16, 2009)

Wow! These look really cool and very reasonably priced. I think I might try one of the cheaper boards in my wife's car for fun. This might be a dumb question, but what would be the best way to trigger the board to turn on since it only has dc power in and no remote input?


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## Lanson (Jan 9, 2007)

subbing, this is sweet stuff right here.


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## gunn234 (Feb 27, 2007)

They have forums within the minidsp website. You would have better luck posting within there for more refined answers. You could use 12v phone chargers to power the modules. I get what you are saying though. A separate remote in for ignition and power straight to the battery.


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## ErinH (Feb 14, 2007)

damn. that's pretty friggin' sweet.

for 3-way + sub you can buy two of the DSP boards (4 channels + 4 channels) and then buy the 4-way plug-in + 2.1 plug-in to have some nice PEQ stuff. 
I'm trying to figure out what the Q is adjustable to. Anyone know?

Very nice. Good info. Thanks.

Now, how to trigger it on and off... 



Edit: I wonder, too, if you're allowed to even combine the PEQ plug-ins with the GEQ plug-ins.
Nope. Can't do it.


> > Can I load 2 plug-ins running simultaneously on the miniDSP kits?
> 
> 
> No, only a single plug-in can run at a time. You can however easily upgrade from one to another with a simple click of a mouse.


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## Lanson (Jan 9, 2007)

This stuff goes along the lines of the ideas for DIYMA amps we talked about years ago. Older members will probably recall those fruitless efforts, like modular amps I drew up. These things look like the real deal though. I'm impressed. Didn't catch it right away, is there a non-digital input for us regular folks?


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> damn. that's pretty friggin' sweet.
> 
> for 3-way + sub you can buy two of the DSP boards (4 channels + 4 channels) and then buy the 4-way plug-in + 2.1 plug-in to have some nice PEQ stuff.
> I'm trying to figure out what the Q is adjustable to. Anyone know?
> ...


Haven't looked closely yet, but if it has DC in and Ground. A latching relay or just a relay.

Use your remote turn from your head to the relay, with 12v as your source. Trun on head - relay opens gives it power, Turn off head - relay closes DSP goes off.


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## ErinH (Feb 14, 2007)

^ cool.

I sent them a lengthy email asking for a couple things:
1) Q width adjustability
2) output voltage
3) is feeding it more than 2v bad (electrically or mechanically)


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## ErinH (Feb 14, 2007)

fourthmeal said:


> This stuff goes along the lines of the ideas for DIYMA amps we talked about years ago. Older members will probably recall those fruitless efforts, like modular amps I drew up. These things look like the real deal though. I'm impressed. Didn't catch it right away, is there a non-digital input for us regular folks?


yea. the basic $99 Rev B version is what we'd use.


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> yea. the basic $99 Rev B version is what we'd use.


If I see this right in order to do a 4 way (tweeter, midrange, midbass and subs) you need two kits. Then buy the plug-in say the 4-way crossover plug-in the 4-way PEQ plug-in. Question maybe I over looked it. Is the Graphic EQ built into the 4-way crossover plug-in? The reason I ask is I don't see a Graphic EQ plug-in.


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## ErinH (Feb 14, 2007)

MiniDSP - MiniDSP Pluggins

They make a 4-way G-EQ plug-in as well.
If you really wanted to go all out, you'd buy three of these and 3 plug-ins. 2 would be your PEQ and control tw/mr/mb/sw. This would give you your crossover points and 'problem solver' EQ. The other would be a graphic eq for L/R to shape the curve. That would be about $330. 

L/R into the g-eq 2 way version. Then L/R out of that one and into the other 2 guys via a splitter. Then out of those 7/8 into your amps.

I think that's right... someone needs to check that.


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> MiniDSP - MiniDSP Pluggins
> 
> They make a 4-way G-EQ plug-in as well.
> If you really wanted to go all out, you'd buy three of these and 3 plug-ins. 2 would be your PEQ and control tw/mr/mb/sw. This would give you your crossover points and 'problem solver' EQ. The other would be a graphic eq for L/R to shape the curve. That would be about $330.
> ...


So your saying.:

2 DSP Kits - Tweeters - Midranges on one. Mid-basses and subs on the other. A PEQ plugin on each as you said problem solver.

In front of them Getting the signal from the Head unit/Source one more kit with the 4-way G-EQ on it using it outputs to feed the other two kits inputs to contour your response. I saw you said the 2 -way G-EQ, would the 4-way better so no splitter is need. The 4-way is for L/R L/R corrcect?

Hmmmm $330

Wow I might have to build on of these


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## ErinH (Feb 14, 2007)

Geq up front off the h/u. Geq is for left/right only. Then the 2 peq's. These 2 would be your tw/mr and mb/sw 4-way out. Splitter used after the left/right geq into each peq where you divide the signal. You can use the geq to draw a curve.


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> Geq up front off the h/u. Geq is for left/right only. Then the 2 peq's. These 2 would be your tw/mr and mb/sw 4-way out. Splitter used after the left/right geq into each peq where you divide the signal. You can use the geq to draw a curve.


Ok I see, i was look at the 4-way Graphic Eq Crossover, the Crossover with the Graphic Eq and 4 way Crossover as one plug-in.

I wouldn't use a splitter. I would just remove the RCA jacks on the outputs of the G-Eq kit and inputs of the 2 P-Eq kits and just hard wire them.

Man I even know of case that would fit the 3 boards in.


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## ErinH (Feb 14, 2007)

You could come up with a few ways, I'm sure. That just seems to me to be a good one. Hatd wire ftw!

I'd like to know how narrow the q can be. I've been hunting a way to get a narrow peq band in my car. This sucker just might be it. Much cheaper than the dsp6 in regards to what I need. 
I'll update you on what I find out. Looks like they're out of japan so it might be a while.


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## Lanson (Jan 9, 2007)

What about time alignment? I agree, these look like a ripping bargain. Now wonder if they have the same issue 3sixty.2's do with noise.


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## mosca (Oct 26, 2009)

Windows only


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## ErinH (Feb 14, 2007)

fourthmeal said:


> What about time alignment? I agree, these look like a ripping bargain. Now wonder if they have the same issue 3sixty.2's do with noise.


has delay built in.


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## katodevin (Feb 14, 2008)

This looks pretty awesome, especially for the newer cars with the crazy integrated sound systems. 

I'm thinking ipod straight into one or two of these guys for a 4-way active setup with time delay and eq. What else do you need!


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## Lanson (Jan 9, 2007)

emailed them, hoping to get an exact parts and software quote to handle a standard 3-way (sub incl.) EQ and time align. Seems smarter than trying to make my 3sixty.2 quiet.


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## gunn234 (Feb 27, 2007)

Here's a nice thread to follow.

It is a work in progress however.

My MiniDSP setup - diyAudio


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## mosca (Oct 26, 2009)

mosca said:


> Windows only


maybe I understood incorrectly how this works. does the plugin need to be used only when the hardware its set up? (i.e. like a Bit One).

edit: *the aswer is yes*



> A miniDSP kit only requires a PC connection for configuration. Once the product properly configured through the mini-USB connection, you can disconnect the board and let it run on its own. Using a simple phone mini-USB charger or external DC power supply is all you need to get your miniDSP kit up and running.


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## 14642 (May 19, 2008)

Wow. This is pretty cool. I dunno whether it's cool for cars, but for computer audio, this might be the ticket.

One thing that concerns me about this in cars is ground isolation. The data sheet indicates that the inputs are "unbalanced". If that means that the analog audio inputs are tied to chassis (power supply negative) directly, there WILL be engine noise. The way to get rid of it will be with ground loop breakers--with transformers. 

REVB takes up to 2V on the RCA input, which is fine for everything but some crazy line drivers. 

If these guys would add USB audio and native ASIO support, they'd own the HTPC and enthusiast PC audio market. Speaker crossover and response correction on the DSP's board and additional processing via VST plug-in in the PC and I'd order 18 of these things ASAP.


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## ErinH (Feb 14, 2007)

^ I'll ask them about this. We've had an email chain going and the response has been good.

Here's some of the email chain...
My questions are underlined, with the answer following.




> Can you tell me the range of values that the Q is capable of?
> *Answer:* Q range is between 0.5 to 50 on all our PEQ enabled plug-ins.
> 
> 
> ...




Did anyone see the 'Q' width range... holy crap! 

The output voltage of 0.9v might be an issue. Yea, yea, increase the gains, I know, but car audio is tricky and sometimes increasing the gains results in more noise floor. I'm not going to get into it. I'm simply saying that it seems like it could be an issue. 

I do like that it's flash memory based. So, it only seems like it would need a switched turn on from the remote wire and a ground. 


I asked for a bit more clarification on some of these. I'll post up the answers when I get them.


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## 14642 (May 19, 2008)

Seriously, ask them about signal grounding. Ideally, the input would be differential and audio ground would be isloated from power supply ground. Output signal should be ground.


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## lycan (Dec 20, 2009)

I haven't read all the details  but here's my questions :

1. Signal grounding (thanks Andy). Is the "negative" or "shield" of the RCA input pin directly shorted to power ground? (When will the world stop this poor practice, by the way? TREAT the input AS IF it were balanced, and the world is a better place).

2. Will the parametric EQ filters also do a second-order "shelving" function ... with selectable Q? If so, we can do a full Linkwitz Transform in DSP, with no more than two filter blocks


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## ErinH (Feb 14, 2007)

Andy, I quoted you in an email to him. I'll post back what I hear.


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## iarechaga (Oct 27, 2009)

I'm with the same questions as you guys!

I'll wait for those replies.

By the way, I've asked them about a 4-Way DSP and we need:


2x miniDSP
1x miniDIGI (for the optical input)
1x 4-Way PEQ plugin
1x 4-Way crossover plug-in

The question now is... the power supply and those you're asking already


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## jsun_g (Jun 12, 2008)

I was thinking one board + 4-way xover/PEQ kit for each side. Unless the pass bands can overlap.

Subscribing as i want to see who tries these things and how they work out in a car.




H-Audio - AKA - Here-I-Come said:


> So your saying.:
> 
> 2 DSP Kits - Tweeters - Midranges on one. Mid-basses and subs on the other. A PEQ plugin on each as you said problem solver.
> 
> ...


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## iarechaga (Oct 27, 2009)

What about the miniDIGI REVB for our possible noise problems?



> MiniDIGI is the easiest path to digital audio input & output connectivity on our miniDSP kits or your custom DIY audio projects. With a flexible architecture and Asynchronous Sample Rate Converter (ASRC), building SPDIF/Toslink powered designs couldn’t be easier. Based on an award-winning TI/Burr & Brown IC, the board is automatically configured by a microcontroller, making it a flexible Plug’n’Play standalone solution for different DIY audio projects.
> 
> See miniDIGI technical datasheet for more details.
> 
> Important Note: *This board is a RevB version with SPDIF transformer providing better common mode noise rejection, impedance matching, isolation from ground loops and short circuit protection.* If you do not require this option, have a look at REVA version instead.


Can it be a solution instead of the balanced rca output?


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## ErinH (Feb 14, 2007)

Okay guys, I got a reply back. I'm hoping you can decipher the questions I asked him from the below because I'm typing this from my phone and don't feel like explaining things...

I've placed an order for a single board and requested the P-EQ software. I hope to have the setup by this weekend's GTG so others can get to see it in person.
That way I'll be able to answer these questions and I'll report my findings back. Look for a full blown review in about a week. 
The owner seems to be VERY willing to offer his assistance and answer our questions so I'll work with him to further discuss the product and options for us DIY folks. 



> 2) With regards to your question about power, I think that you already got the answer figured out, but the answer is that we have a switching regulator on the input allowing a wide range of un-regulated power supply on the input.
> In an environment like a car where power fluctuates a lot, this would come in handy. +12Vdc straight to the unit is fine. As for your other email where you asked what I meant by male to male, I was implying that the connector on the module is a 20pin Female connector (looking like this: 68683-303 FCI FFC / FPC Connectors ) Have a look at the tech note about External DC connectivity posted here. You will see what I mean by connector. MiniDSP - Downloads
> 
> 3) With regards to the high output, the 0.9Vrms is a limitation of the board and there isn't much we can do without 1) modifying the hardware 2) or the other option would be to add a line driver with a gain to allow a much higher signal.
> ...


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## masswork (Feb 23, 2009)

Hi Bikinpunk.

Who's your contact at miniDSP? Is it Tony?

I've built one of this (RevB - analog), it sounds good. 
It needs a good power supply. I ended up building a 5v USB power supply - instead of using 12v. 

Watch out for turn on and off thump hough


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## masswork (Feb 23, 2009)

One thing that's lacking from this ADI based chip is auto-tuning.
if auto tuning is included, it may well compete with MS8


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## ErinH (Feb 14, 2007)

^ You know, I don't have his name. It's an auto-signature. I'll be sure to ask it, though. I've already sent an email tonight and am about to go to bed. 

Did you feel that 12v was not good enough? Any particular reason why? 

Regarding turn-on/off, I'm going to let my bitone trigger it on/off via the remote turn-on outputs it has. The remote triggers are on ~10s delay for start up and shut down so hopefully all will be well in this regard. 
I'm curious to see just how the 2v input, and 0.9v output will fare. I don't know if I'm being overly critical or not. I already have a slight noise floor that I'm okay with, but am not looking forward to having more. 

If you have input on what you've experienced would be appreciated. I know we're all interested to hear more. I just wanted to go ahead and try it myself and see what it's about. Easiest way to answer my concerns. As noted, I'll try to post up a thorough review once I get it installed and have a chance to use it.


Edit: 
Re: Auto-tuning. 
I plan to ask him about potential future plug-ins and will ask about auto-tuning as well. We've had quite the discourse so far. I don't wanna hammer down his inbox any further, lol.


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## MarkZ (Dec 5, 2005)

Wait, I don't get it. So, this thing handles four channels, and then you buy software plugins for it, right? Is there any information about 1) what DAC does it use? 2) Is there a USB interface version (nevermind digital/analog input)? Seems like it could have potential for a low-cost carPC project so that you don't have to go tits out on a high powered PC and all the cooling it needs to do VST plugins.


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## masswork (Feb 23, 2009)

bikinpunk said:


> ^ You know, I don't have his name. It's an auto-signature. I'll be sure to ask it, though. I've already sent an email tonight and am about to go to bed.
> 
> Did you feel that 12v was not good enough? Any particular reason why?
> 
> ...


When i use 12v PS, alternator whine is everywhere 
When i switch to 5v, everything sounds ok.
Maybe it's my PS design... 
Anyway 5v gets the job done 

The noise floor is inaudible.
I've tried connecting this unit to several amps, with input sensitivity set to 0,2 - 5v -> no hiss. Not until i connect the input of this unit to my noisy HU 

Yeah, i heard they're trying to integrate this unit with REW. Not sure how's they progress though.


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## ErinH (Feb 14, 2007)

more details on the 5v PS design? I may wind up having to go that route if I get alt whine via 12v...


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## masswork (Feb 23, 2009)

MarkZ said:


> Wait, I don't get it. So, this thing handles four channels, and then you buy software plugins for it, right? Is there any information about 1) what DAC does it use? 2) Is there a USB interface version (nevermind digital/analog input)? Seems like it could have potential for a low-cost carPC project so that you don't have to go tits out on a high powered PC and all the cooling it needs to do VST plugins.


One board can be configured as:
2 input (stereo) -> 2 x 2 channels out
or 
1 input -> 4 channels out.

So, if we want a 4 way active crossover, we need 2 boards.

Is it ok to post the chip this board is using?
Or is it against some law somewhere?


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## masswork (Feb 23, 2009)

bikinpunk said:


> more details on the 5v PS design? I may wind up having to go that route if I get alt whine via 12v...


Standard DC-to-DC converter. The IC is MCxxxx (forgot the code).
Nothing magical.

Don't try using 78xx!


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## MarkZ (Dec 5, 2005)

Haha there's a law for everything.

I was interested to see if they have a version where the "input" is actually USB. Use the thing as a sound card.


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## masswork (Feb 23, 2009)

MarkZ said:


> Haha there's a law for everything.
> 
> I was interested to see if they have a version where the "input" is actually USB. Use the thing as a sound card.


As of now, i don't think we can send digital input to this board's USB port.
They do provide I2S connection. But that's too much work for me 

Here's the block diagram, hope it helps










PS: The DSP is "standard", not the automotive version.


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## lycan (Dec 20, 2009)

Who wants a long lupine post? I can already feel the love ...

There's really _two_ separate issues with "ground noise" in a system where the "signal ground" is tied to "power ground", at BOTH the source AND receiver ends. One of them is NOT unique to car audio, and the other one is only "more common" in car audio. These two problems are _always_ confused 

But let's get the picture straight first. You have a SOURCE (headunit, CD player ... remember CD's?) whose power is referenced to its LOCAL ground. And you have a RECEIVER (amp, preamp) that's grounded to its LOCAL ground ... which is DIFFERENT than the SOURCE ground. It may be DIFFERENT only because it's in a DIFFERENT place. Now, you send a signal from SOURCE to RECEIVER. And you short the "signal ground" to the "power ground" at the source, and you short the "signal ground" to the "power ground" at the receiver.

Now we can look at the two potential (pun) problems :

1. *Ground loop*. In this system you've created a "ground loop", or big ground circle, that consists of the RCA shield conductor, and whatever ultimately connects the power grounds of source & receiver (in car audio, that's most likely the car chassis). What's the problem with a "ground loop"? In simple terms, it forms an "antenna" that you can INDUCTIVELY couple noise into. And that noise will manifest as a VOLTAGE in SERIES with the loop. Ultimately, the receiver will have no choice but to "interpret" this _induced noise voltage_ as signal  This problem is NOT unique to car audio. But it's only the _first_ reason why grounding the RCA shield (or "signal ground") to "power ground" at the receiver is a _bad_ idea.

2. *Common impedance*. The problem here, often confused with a "ground loop", is that you may have HUGE ground currents flowing through the "conductor" that physically connects the "power grounds" at the source & receiver ends (car chassis, again). These ground currents will ultimately cause a "potential difference" between the source & power grounds. When you connect the "signal ground" to "power ground" at the receiver end, the receiver has no choice but to interpret this "ground noise" as signal  This problem may very well be _more common_ in car audio than home audio, because we have some huge ground currents flowing through the chassis. More often than not, this is how "alternator whine" finds its way into the signal path.

BOTTOM LINE : *Robust signal transfer should not create a ground loop where there wasn't one in the first place, nor should it rely on source & receiver grounds being at the same potential.* And the problem is _not_ unique to car audio. 

The *solution* is simple : treat the signal as a differential or balanced signal at the receiver end, even if it is single-ended or unbalanced  The price is one opamp and 4 resistors per channel. Or, one transformer per channel. But op-amps are cheaper, especially at lower frequencies.


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## masswork (Feb 23, 2009)

Yes Lycan.
Agree 100% with the noise issue.

Btw any hint for good opamp that can run on single supply 5v?


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## Melodic Acoustic (Oct 10, 2005)

This make me wonder if one of the CarPc power supplies would work like the M1/M2-ATX as they should put out a 5volt source for the mother boards to use. They have a anti thump circuit built in and are design to be quite. This should work. as a good DC-DC power source for the units. They are a little costly but should work.

M1-ATX 80W Automotive Grade Power Supply for Mini ITX Carputers

M2-ATX 140W High Voltage Mini ITX PSU for Carputers


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## masswork (Feb 23, 2009)

Andy Wehmeyer said:


> Seriously, ask them about signal grounding. Ideally, the input would be differential and audio ground would be isloated from power supply ground. Output signal should be ground.


Hi Andy,
if i'm not mistaken, the ground surronds the whole PCB.
And both RCA in and out is attached to it.
It's not isolated.

Adding differential preamp like Lycan suggested is a good idea...


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## MarkZ (Dec 5, 2005)

H-Audio - AKA - Here-I-Come said:


> This make me wonder if one of the CarPc power supplies would work like the M1/M2-ATX as they should put out a 5volt source for the mother boards to use. They have a anti thump circuit built in and are design to be quite. This should work. as a good DC-DC power source for the units. They are a little costly but should work.
> 
> M1-ATX 80W Automotive Grade Power Supply for Mini ITX Carputers
> 
> M2-ATX 140W High Voltage Mini ITX PSU for Carputers


Another reason why I'm thinking about this. I have an accessory supply in my Carnetix that's not doing anything. 

Still kinda pricey for me, and it doesn't seem to do anything that I can't do in foobar2000's DSP plugins. Still, it would keep me from having to buy a better multichannel sound card.

But like I said earlier, this sounds like a really good solution for people who want to run a carPC but don't want to deal with having to fit a Pentium 4 in a tight place and reroute their air conditioning, etc. Instead, you let your carPC run near 0% CPU and let this device do all the heavy lifting.


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## ErinH (Feb 14, 2007)

masswork said:


> Standard DC-to-DC converter. The IC is MCxxxx (forgot the code).
> Nothing magical.
> 
> Don't try using 78xx!


Oh, gotcha. A standard PSU. I was thinking of something more complex. 

You said a USB power supply, so I was wondering if you tell me what you meant by 'usb'. Does your power supply provide power via USB, or do you have a power supply that gets power via USB from a usb car adapter. I assume the former.
It's been a few years since my last computer build.


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## ErinH (Feb 14, 2007)

Jeff, I forwarded your post to them. I also invited him to join in the discussion here. I'm not sure if he'll be able to but I thought it might be easier for you guys to ask him directly. I have a basic understanding of the grounding issues and types but I'm not as fluent in it so it takes me a couple think-overs. 

I'll post back what I hear should he not be able to sign up.


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## ErinH (Feb 14, 2007)

lycan said:


> But let's get the picture straight first. You have a SOURCE (headunit, CD player ... remember CD's?) whose power is referenced to its LOCAL ground. And you have a RECEIVER (amp, preamp) that's grounded to its LOCAL ground ... which is DIFFERENT than the SOURCE ground. It may be DIFFERENT only because it's in a DIFFERENT place. Now, you send a signal from SOURCE to RECEIVER. And you short the "signal ground" to the "power ground" at the source, and you short the "signal ground" to the "power ground" at the receiver.


I’ve never really sat down and looked at the physics of what makes a ground loop or alternator whine, so forgive me if I’m misunderstanding here. If you have links or references to reading to help me better understand I’m more than happy to read them. 
First off, the way I understand your post is that ‘signal ground’ would be an RCA ground shield and that ‘power ground’ would simply be the grounding wire we use to complete the components’

If the above is true, then I interpret your post as the following for what we see in car audio:
We use different power grounds to ground a component typically because it’s easier to ground locally than run a wire all the way back to the battery (or where you may try to tie all grounds to via a block). 
On their own, this is okay. 
The problem arises, however, when you connect signal between the two components via an rca. The RCA ground (signal ground) is then referenced back to the local ground of whatever component your RCA is connected to and therefore the differential you had in grounding voltages is then relevant. Because you’ve done this, you now get the voltage interpreted as audio and your system plays this back. This is how we get alt whine.

Is this correct?
If so, then would you say that by grounding all your audio components together at a common ground point (via a distro block or the like) would eliminate the potential for either impedance or voltage differentials? In my car I have all audio components grounded to a common ground which has all but eliminated alt whine from my car stereo (sans a few instances due to battery capacitance).


If so, then is the balanced version of this nothing more than having 2 center conductors which are inverse of each other allowing for cancellation of voltage differential? In balanced connections, the shield is not the ground. The ground is part of the 2 center conductors. No?

Also, I’ve seen where one shield is grounded but on the other end it is not; it is ‘lifted’. Is this version what you’re calling differentially balanced? 

This stuff can be confusing. Hope I’ve made some semblance of sense.


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## masswork (Feb 23, 2009)

bikinpunk said:


> Oh, gotcha. A standard PSU. I was thinking of something more complex.
> 
> You said a USB power supply, so I was wondering if you tell me what you meant by 'usb'. Does your power supply provide power via USB, or do you have a power supply that gets power via USB from a usb car adapter. I assume the former.
> It's been a few years since my last computer build.



Oh, sorry for that 
My PSU is a standard 5v that can power a USB device 
It's connected to external DC pin, not through USB port. 

Yes, USB car adapter can also be used.


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## ErinH (Feb 14, 2007)

masswork said:


> Yes, USB car adapter can also be used.


Amazon.com: Scosche Dual USB Car Charger: Cell Phones & Service

that would work for 2 boards...
combine with 2 USB cables and you'd have power for it (potentially worry free) for less than $20.


masswork, when you first used 12v, did you solder the leads on or use a block connector of some sort?
Also, when you program your settings, you use a laptop via USB to power it on, then pull that cable and plug into the power supply's usb output?
I may order the USB car charger above just to have on hand.

Aaaaand, finally… the spec sheets show miniUSB in one and USB in another for connection. Can you verify which one it is? From the pictures it looks like standard usb female input, but I’m not so sure.
I’d need to order a 12’ cable to run from the front to the back of the car so I’m trying to make sure that mini USB is correct.
For only $1.61 each when QTY 50+ purchased - USB A to mini-B 5pin 28/28AWG Cable - 15FT | USB 2.0 Cables - Mini-B 5pin Type


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## ErinH (Feb 14, 2007)

Slopes
GUI on one screen/tabbed

Mark, you and I talked a bit about the GUI controlling and discussed how it may be a pain in the butt considering how the Zapco DC amp software is. 
I was thinking about it a bit more. Each of these suckers requires its own USB input, which means if you’re running two boards then you’re using 2 usb cables.
In this case, it may be that we can jump from one screen to the other easily rather than having to save changes and switch to another board in the same software/plugin. I think. I’ll have to ask about this, though.

If each board’s plug-in is separate in programming from the other one, then you should be able to just minimize one plug-in screen and work on the other board via the 2nd plug-in screen. Or, if you have 2 monitors you can have both of them up at once. 

Just thinking about that…


Found this thread in their forum as well. Looks like more crossover slopes are coming, and there are indeed bandpass filters on the 4-way version. 
MiniDSP - 3-way - MiniDSP


This company looks to really be listening to the users. I’m really looking forward to getting mine in and playing around with it a bit. The great thing about them is that (from what I can tell) once you purchase a plug-in, you get future updates for free. I do, however, wonder if you update to a new version, do you lose your previous settings?


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## masswork (Feb 23, 2009)

bikinpunk said:


> masswork, when you first used 12v, did you solder the leads on or use a block connector of some sort?
> Also, when you program your settings, you use a laptop via USB to power it on, then pull that cable and plug into the power supply's usb output?
> I may order the USB car charger above just to have on hand.
> 
> ...


Both my 5v and 12v PSU uses male header connector directly to external DC pin. The PSU is always powering this device either when connecting to laptop or not.

I think in the package you'll receive the same cable (USB-A to mini). So if you need longer cable, you can use a USB extension cable (A to A) too.

Like this one:
Amazon.com: Belkin F3U134-10 USB Extension Cable (10-Feet): Electronics


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## lycan (Dec 20, 2009)

bikinpunk said:


> I’ve never really sat down and looked at the physics of what makes a ground loop or alternator whine, so forgive me if I’m misunderstanding here. If you have links or references to reading to help me better understand I’m more than happy to read them.
> First off, the way I understand your post is that ‘signal ground’ would be an RCA ground shield and that ‘power ground’ would simply be the grounding wire we use to complete the components’
> 
> If the above is true, then I interpret your post as the following for what we see in car audio:
> ...


Grounding to a single point helps eliminate ONE of the two problems i discussed : the "common impedance" problem. BUT ... you still have the "ground loop" problem, if you tie signal ground to power ground at _both_ ends of the signal transmission (source & receiver).

By the way, that's more of a problem in geometry, than electrical engineering  If you can identify a loop of wire that "involves" ground, then you have a ground loop. If you can identify that massive current flowing somewhere will cause a potential difference (even tiny) in two grounds ... and the signal is referenced to those two different grounds at two different points ... then you have a common impedance problem.

Transformers in the signal path break ground loops, and are blind to different ground potentials (which show up as harmless "common mode"). Differential opamp input stages essentially accomplish the same thing.

The key that is often overlooked is this : *there's nothing that stops the receiver from interpreting the input as balanced, even if it's not.* It doesn't matter that the cable is RCA instead of balanced. It doesn't matter that one side is source-grounded, instead of source-inverted.

*The receiver should "observe" the DIFFERENCE between the two input conductors, without trying to "force" one of them to a local potential.*


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## ErinH (Feb 14, 2007)

masswork said:


> Both my 5v and 12v PSU uses male header connector directly to external DC pin. The PSU is always powering this device either when connecting to laptop or not.
> 
> I think in the package you'll receive the same cable (USB-A to mini). So if you need longer cable, you can use a USB extension cable (A to A) too.
> 
> ...



yea, i've got a few extension cables.
I may have a mini at home... can't remember, though.

I think the easy route would be the car usb cigarette adapter. Plug it in to power it... unplug to program it. No worrying about ground loops/alt whine.
If I were to use the board, I suppose I'd have to solder directly to it or order a block for it and I'd rather not have to do either at this point. Plus, I'd already have to run a USB cable the length of the car to program from the front seat, so an extra $10 on a car charger USB port is not a big deal.

once I get this in, I'm sure it'll be rather easy to set up. I'm just trying to do this from pictures and want to make sure I have everything ready to go. Nothing worse than getting a new toy in and then spending an hour or days trying to get a cable for it.


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## masswork (Feb 23, 2009)

bikinpunk said:


> Slopes
> GUI on one screen/tabbed
> 
> Mark, you and I talked a bit about the GUI controlling and discussed how it may be a pain in the butt considering how the Zapco DC amp software is.
> ...


Well, you can only connect one board to your laptop at a time 
I think the software limits it.

The board allows write operation - but not read operation.
So it's better if we save the setting in our laptop. The setting is saved as XML file.

So, whenever we connect the board to our laptop - it will synch (load) with setting that's currently loaded in our laptop.

Oh, also we need Adobe AIR to run the plugin in our laptop.
It's free from Adobe: Adobe - Adobe AIR


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## ErinH (Feb 14, 2007)

masswork said:


> Well, you can only connect one board to your laptop at a time
> I think the software limits it.
> 
> The board allows write operation - but not read operation.
> ...


Then that could be a problem.
With the Zapco dc amp software, one has to save config on one amp before switching to another. What’s annoying about this is if you have tweeters/mid on one amp, and midbass/sub on another. Say you then want to mute the entire left side (for whatever reason, and I do this a lot actually via my bitone). To do this, you’d have to mute the channels on one amp, save, load other amp, mute, save, go back to first amp to start playing, save, load other amp, play around, save… this kind of process is horrible and I know others use other methods which require a process similar to what I’ve illustrated.
That’s the SOLE reason I dropped the Zapco setup I had. That was a MAJOR pain in my side. The bitone allows you to mute/eq/etc any channels you want without switching GUI’s because it’s all on one screen.
If the miniDSP would allow you some sort of tabbed networking interface so that you would be able to work with multiple DSPs without going through a save/load procedure that would be wonderful. If not, that would be a downfall and one that I frankly would have a very hard time working around. I know others who feel the same way. 


Thanks for the reminder on AIR. 



I’ve also been considering the idea of the remote turn on activating my cigarette lighter’s power. I’m not sure exactly if hacking a cigarette lighter adapter so that the 5v power is received from my DSP’s remote turn on 12v+ with a resistor wired in to make it 5v would work and still allow me the worry free issue of alt whine. The goal here would be to avoid turn-on thump. Of course, it may not be an issue with my setup since the bitone delays the turn on of the amps and the miniDSP would have already been powered on with acc start up. Hmmmm….

I love over analyzing things.


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## masswork (Feb 23, 2009)

bikinpunk said:


> I think the easy route would be the car usb cigarette adapter. Plug it in to power it... unplug to program it. No worrying about ground loops/alt whine.
> If I were to use the board, I suppose I'd have to solder directly to it or order a block for it and I'd rather not have to do either at this point. Plus, I'd already have to run a USB cable the length of the car to program from the front seat, so an extra $10 on a car charger USB port is not a big deal.
> 
> once I get this in, I'm sure it'll be rather easy to set up. I'm just trying to do this from pictures and want to make sure I have everything ready to go. Nothing worse than getting a new toy in and then spending an hour or days trying to get a cable for it.


Yeah, i also used a car USB adaptor before building my own PSU.

It's very easy to setup, when everything is in place 
It took me 2 days trying to solve what went wrong with my 12v PSU. It's weird. Not only alt whine, but i also got a "beep beep" in synch with the blue led blinking in the board 

Anyway... now those problems are gone.
And i'm very happy with this small board.


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## ErinH (Feb 14, 2007)

cool.

I'm going to power it like I would any other device (12v, ground) just to see if I have the same problems in my car. 
But, I'm going to go ahead and order the car usb adapter just to have should I need it. 
The question I'm wondering is if the turn-on thumb is going to be an issue.
I'm thinking of these things for myself in my own situation knowing my own setup, but also knowing other potential setups and since I'm trying to be the guinea pig I want to be able to image potential issues others may face.


A bit OT... did you make a case for yours?


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## masswork (Feb 23, 2009)

Btw,
what features does this DSP offer that's not there in bitone?
Just curious.. i thought bitone has everything?


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## ErinH (Feb 14, 2007)

parametric EQ, namely.

That's really all I can think of.

Dude, I'm PUMPED on a Q of 50, LOL.


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## masswork (Feb 23, 2009)

Ah, i see 

I bought a small plastic box like this:









Drilling, soldering and finally hot glue


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## ErinH (Feb 14, 2007)

cool. I'll have to swing by RS sometime this week to try to pick something up that will work.


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## jsun_g (Jun 12, 2008)

I'd take a parametric EQ over graphic anyday. Looking forward to seeing how your project works out. I already have the parametric EQ covered (old school Apline 3402, Q varies from 1 to 100!), but it'd be nice to get everything in a small package like these boards offer.




bikinpunk said:


> parametric EQ, namely.
> 
> That's really all I can think of.
> 
> Dude, I'm PUMPED on a Q of 50, LOL.


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## ErinH (Feb 14, 2007)

IMO, ideally a 31band g-eq + parametric to pinpoint particular trouble spots is ideal. I’ve gotten a good overall response with the graphic but have 2 bands that I need help on and graphic can’t touch them. Especially not with the Q I need. So, I’m really looking forward to this thing.

I’m going to have to figure out just how I’m going to power it, though. I don’t really want a cigarette adapter with cables running out of it as it just kills the look of things, imo. I’m going to have to think of a way to hard wire it in. I just wonder, if I hack the adapter, and use my distro block ground and then the power from the distro block coupled with a voltage regulator to drop the output voltage to 5v, is this going to essentially give me the same results if I were to wire directly to the board, or is the USB a way of breaking the uncommon ground?
of course, there's probably a circuit already built into the adapter that I may be able to use and not have to build a voltage divider or regulator.

Edit: now, this might be a plausible adapter...
Amazon.com: Multi-Use Vehicle Charger with Dual USB Ports and Dual 12 Volt Sockets - Magnadyne: Cell Phones & Service

You can screw it in to your dash trim wherever you'd like and it would look sort of oem. I think I may order that guy as it leaves me multiple outlets to still use a standard car adapter for my phone, etc, should I need it.


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> IMO, ideally a 31band g-eq + parametric to pinpoint particular trouble spots is ideal. I’ve gotten a good overall response with the graphic but have 2 bands that I need help on and graphic can’t touch them. Especially not with the Q I need. So, I’m really looking forward to this thing.
> 
> I’m going to have to figure out just how I’m going to power it, though. I don’t really want a cigarette adapter with cables running out of it as it just kills the look of things, imo. I’m going to have to think of a way to hard wire it in. I just wonder, if I hack the adapter, and use my distro block ground and then the power from the distro block coupled with a voltage regulator to drop the output voltage to 5v, is this going to essentially give me the same results if I were to wire directly to the board, or is the USB a way of breaking the uncommon ground?


Let me look around I think I May have a M1-ATX power supply somewhere that you can use. Give it 12V and found the 5 volt wire/s to are on the Harness that go out to the Mother board. Hell if I can find it will find the wires for you and put connectors on the ends to make it easier for you. If I build one this is the PSU I will be using it cost a bit but it has very thing we need.


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## ErinH (Feb 14, 2007)

^ so, a voltage regulated board? 

The only real problem I have with the car charger is simply that the location of the charger in my car kind of sticks out a bit. It's just in an awkward place and might cause other things to look more junky.
I'm thinking I could buy the above adapter, cut the adapter end off, and tap into the backside of the oem adapter.


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> ^* so, a voltage regulated board*?
> 
> The only real problem I have with the car charger is simply that the location of the charger in my car kind of sticks out a bit. It's just in an awkward place and might cause other things to look more junky.


Hmmm yes, it used to power carpc's, they have smart circuit buit in with anit-thump so no turn on and turn off noise.


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## lycan (Dec 20, 2009)

bikinpunk said:


> parametric EQ, namely.
> 
> That's really all I can think of.
> 
> Dude, I'm PUMPED on a Q of 50, LOL.


Can you find out if the parametric EQ can also perform a "shelving function"?

It's basically a second-order block where the numerator & denominator in the transfer function have _different_ resonant frequencies. And the resulting frequency response looks like a "shelf"  By the way ... Zapco DSP has it  And it allows a pretty straightforward digital implementation of a Linkwitz Transform 

For reference : the standard, "peaking" second-order block has a numerator & denominator with the same resonant frequency, but different "Q".


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## ErinH (Feb 14, 2007)

I'll ask about that.

I'm aware of how the shelving works.  I owned their DC amp line for a short stint.
FWIW, The Q on the zapco is capable of up to 9, though you have to manually type in anything above 6 because the drop down selector only has 0.5-6.


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## ErinH (Feb 14, 2007)

Alright, guys. Here is the response I got back yesterday about grounding. You’ll have to look at my previous posts to see what he was talking about in previous suggestions.



> In ProAudio (our field), balanced audio is very common and is 3 wires: 1 shield, 1 Live, 1 Return. (XLR). Live and Return are twisted such that if there is EMI (and there always is), it will be on both Live and Return equally. That induced common mode noise is what the differential input of the input stage will remove. In our applications, we also never connect the shield to both sides, only on one side (typically the output) to prevent a ground loop.
> I'm guessing (once again, not knowing entirely the field), that what must be common in CarAudio is what's so called "forward referencing". Basically, an unbalanced electronic output driving an active balanced input. That would be the path that makes sense to me... See attached a diagram of an app note I put together a while back about these things, don't have the diagram anymore in soft format... Anyway, balanced input isn't on the miniDSP so that's not a very useful case I'm giving you. Although with a simple op amp and few components, it could be added to the input stage if you knew a bit of electronic.
> Most of our clients are using this product in Hifi multi-way crossovers and not having any noise issues... The work around I'd guess will be when we release our newest balanced in/out board which will 1)have much higher driving/receiving capabilities 2) will be fully balanced in&out and allow you this configuration. For the time being, you can use the work around I suggested earlier and I'd think that it should do the trick. my 2cts.



I’ve already ordered a usb car adapter. I may wind up setting this up on the bench at first just to play around with it out of the car. I’m hoping it comes in by Saturday so those who attend my GTG can get to play around with it and see it. 
Then I’ll try to put it in the car early next week. I’ve got 3 sets of drivers to try out this week and I’m already stretched for time as is trying to get ready for the GTG. 

I ask, anyone who has comments or suggestions to go to their forum and post them up. Or , if you send an e-mail to post up the reply here so we can see the response to avoid asking redundant questions. Most of the questions being asked have already been answered on the forum, to my surprise. 
I asked about the switching of GUI’s between boards and it looks like a no go:
http://www.minidsp.com/support/forum/3-suggestion-box/332-tabbed-gui-for-multiple-dsps#335


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## MarkZ (Dec 5, 2005)

So that basically means you're stuck at 4 channels? So what use is this to us?


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## ErinH (Feb 14, 2007)

No, you're not stuck at 4 channels.

You can use multiple boards. However, you have to save and close out one GUI, it seems, before you can open up the other board's GUI. My question was asking specifically if there was a way or potential to get around this. Apparently there's not. And, apparently we're wrong for having the need to do so according to the first reply. Shame on us.


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## masswork (Feb 23, 2009)

Adjusting one board - for one side L/R at a time should be enough i think?


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## Lanson (Jan 9, 2007)

Yes I'm in contact w/ the guys at miniDSP (like a lot you here), and they currently lack the ability to open multiple instances of card software at the same time, but they COULD do it in the future if there is demand. I think we can create the demand, plus a form of soft turn-on via software to avoid pops.


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## MarkZ (Dec 5, 2005)

fourthmeal said:


> I think we can create the demand, plus a form of soft turn-on via software to avoid pops.


This should be handled in the power supply, not on the board.


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## ErinH (Feb 14, 2007)

MarkZ said:


> This should be handled in the power supply, not on the board.


if it can be done on the board, that would be nice.
the bitone has a delayed trigger on output. 

the thing I know the guys are trying to keep from doing is having too many different products. So, likely, it's up to us to take care of the turn-on pops.


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## Lanson (Jan 9, 2007)

bikinpunk said:


> if it can be done on the board, that would be nice.
> the bitone has a delayed trigger on output.
> 
> the thing I know the guys are trying to keep from doing is having too many different products. So, likely, it's up to us to take care of the turn-on pops.



True, but couldn't it just be in the software aka plug-in? That makes it virtually free, and not a new product.


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## ErinH (Feb 14, 2007)

I'm not sure. You just mean a delayed start up of the board itself?

I thought you were talking about having a triggering output.

As long as your board turns on before your amps do, I believe that's how you avoid turn on thump. So, set your amps to a delayed turn on via a timed relay like this:
DEI 528T Relay Module Pulse timer relay module for Python® security systems at Crutchfield.com

That should solve your turn on thump issues.


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## Lanson (Jan 9, 2007)

U know, using just one of these w/ a 3sixty.2 or a strong 3-way capable head unit could be an easy answer to 4-way. Hmmm...


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## masswork (Feb 23, 2009)

I think most amps have delayed turn-on these days, no?
It's the turn-off thump that's driving me nuts. Anyway, a simple cap, transistor, diode, resistor, and a relay can fix it (for less than $5).


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## masswork (Feb 23, 2009)

fourthmeal said:


> U know, using just one of these w/ a 3sixty.2 or a strong 3-way capable head unit could be an easy answer to 4-way. Hmmm...


360.2 is using Analog Device DSP too, right?
Not sure which model though


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## Lanson (Jan 9, 2007)

The hissy kind, apparently. 


/joke.


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## wdemetrius1 (Aug 16, 2007)

fourthmeal said:


> U know, using just one of these w/ a 3sixty.2 or a strong 3-way capable head unit could be an easy answer to 4-way. Hmmm...




That's a very good idea.


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## Lanson (Jan 9, 2007)

Might want to put it on the tweeters, which don't need 31 bands of EQ, and since the 3sixty.2's noise mainly affects the tweeters (I've found), maybe the mini-dsp with a lower noise floor can pull just tweeter duty. And if that in fact is so, you can run an instance of 3sixty.2 software AND an instance of minidsp software at the same time, thus you are able to tune the whole system at once.


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## dbiegel (Oct 15, 2006)

I'd love to figure out a way to do modern surround processing like Logic 7 with this.

It doesn't seem very cost effective to me to buy a bunch of these use for regular processing (EQ & time alignment). There are plenty of ready to go processing options on the market to do that already for less $$.

Rather than invest time in this, I wish someone would help hack the software of the H650/H660. There's already relatively high quality hardware in place to do 512 band FIR EQ per channel, time alignment down to the nanosecond, and automated room correction. All we need to do is bypass/hack the lame software it comes with (doesn't seem that hard to do) and control the hardware to do with it as we see fit.


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## thehatedguy (May 4, 2007)

If it has a turn on thump (like proaudio processors), delay the amps turning on, and power up the DSP board first. I use a PAC TR-7 to delay my amps a few seconds after the Rane gets on and powered up.


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## ErinH (Feb 14, 2007)

^ that's what I plan on doing. Except, I'm letting my bitone switch the amp's on as usual, but tieing the turn-on going to the bitone into this guy.

I linked a delay amp turn on device yesterday, I believe.


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## ErinH (Feb 14, 2007)

Well, I just saw a 'sorry we missed you' note on my door from USPS. They tried to deliver the miniDSP but no one was here to sign for it. I'll be picking it up tomorrow. Stay tuned for pictures...


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## wdemetrius1 (Aug 16, 2007)

Nice!!! I'm looking forward to it.


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## SIMJEDI (Apr 12, 2010)

Another problem you might run into is a turn off thump, they may turn off before the amps.
Some way to keep it on until your amps shut down will help.


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## masswork (Feb 23, 2009)

They do turn off faster than the amp.
3 of my amps at least


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## ErinH (Feb 14, 2007)

SIMJEDI said:


> Another problem you might run into is a turn off thump, they may turn off before the amps.
> Some way to keep it on until your amps shut down will help.





bikinpunk said:


> As long as your board turns on before your amps do, I believe that's how you avoid turn on thump. So, set your amps to a delayed turn on via a timed relay like this:
> DEI 528T Relay Module Pulse timer relay module for Python® security systems at Crutchfield.com
> 
> That should solve your turn on thump issues.



there you go. 

my bitone delays the turn on/off of my amps, so I'll just wire this into the remote trigger from my headunit so it turns on first.


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## iarechaga (Oct 27, 2009)

bikinpunk said:


> Well, I just saw a 'sorry we missed you' note on my door from USPS. They tried to deliver the miniDSP but no one was here to sign for it. I'll be picking it up tomorrow. Stay tuned for pictures...


how much were the shipping costs?

Is it send from Hong Kong or from USA?


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## ErinH (Feb 14, 2007)

sent from HK. I paid about $35 shipping costs. I'm sure it will vary from location to location within the US, still, though. Or, that could be a flat rate cost. I don't know how the company handles that.


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## Sulley (Dec 8, 2008)

Would a line driver such as the AudioControl Matrix ran after the miniDSP be a good idea? just to help that 0.9v along or would noise become an issue?


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## MarkZ (Dec 5, 2005)

I can think of very few reasons to ever use a line driver.


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## ErinH (Feb 14, 2007)

yes, it would in theory. not sure it's 100% necessary, but it's the one reason why I would use one.


Alright, I got the little guy and toyed around with the software a bit.
A few notes about the 2.1 P-EQ plug-in:
1) You can overlap bands of p-eq. That means you can stack a 71hz band on top of a 70hz band, with any Q and level you want. 
2) You can type in any crossover point you want. Crossovers are also bypassable.
3) There's 6 bands of p-eq per channel. However, there's also 6 bands of p-eq for input as well. 
4) Q ranges from 0.5 to 50. 50!!! 
5) Level of eq adjustment is +/- 16dB. 


I think I"m going to wind up building a makeshift bookshelf set with my scans and h-audio enigmas I have on hand just for testing. 

Won't be installing this in the car for a few more days as I just don't have the time. Plus, I think we're better served to let others use it at the GTG on a bench setup just to see what it can do. I have both the 4-way & 2.1 P-EQ plug-ins on hand for people to check out.


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## iarechaga (Oct 27, 2009)

Which slopes are available? 6, 12, 18 and 24db?


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## ErinH (Feb 14, 2007)

They're fixed per filter type.
Butterworth/Bessel second order (-12dB/oct)
Linkwitz-Riley fourth order (-24dB/oct)


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## Sulley (Dec 8, 2008)

MarkZ said:


> I can think of very few reasons to ever use a line driver.


true enough. 

so all I need to get this up and running is a miniDSP+software and some sort of usb car charger?...amazing


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## iarechaga (Oct 27, 2009)

bikinpunk said:


> They're fixed per filter type.
> Butterworth/Bessel second order (-12dB/oct)
> Linkwitz-Riley fourth order (-24dB/oct)


Sorry to bother you again... Can you make a frequency list available on the crossover?

I see it a bit short of options with only those slopes!


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## ErinH (Feb 14, 2007)

what?


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## iarechaga (Oct 27, 2009)

The frequencies where you can start the HPF and the LPF, like 2,5khz - 3Khz and so on


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## ErinH (Feb 14, 2007)

you can start them at any point.

as I said earlier, you can type in any point you want. 20-20khz.


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## iarechaga (Oct 27, 2009)

Ah ok, thanks. I thought it would be like the bit one, with fixed points.


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## masswork (Feb 23, 2009)

Bikinpunk,
how's the result so far?
Does the 2.1 PEQ plugin sound good?

Mine is using the GEQ version now...


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## wdemetrius1 (Aug 16, 2007)

Updates?


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## ErinH (Feb 14, 2007)

Coming. Been extremely busy the past week and am trying to get caught up.


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## ErinH (Feb 14, 2007)

MiniDSP - New Plug-in Release! - MiniDSP

Looks like they’re about to release a new version of the P-EQ plug-ins that allow for steeper crossover points (as high as 48/dB) and high/low shelf, as well as bandpass for the 2.1 plugins. 

I’m still waiting on a couple things to get here before I have the chance to put it in the car, but so far I’m impressed. 

I’ve been extremely busy lately with various things, but I’m going to try to at least get started on a review this weekend. 

-	Erin


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## ErinH (Feb 14, 2007)

Alright, I finally got the piece in I was waiting for and spent about 3 hours with this guy in my car on Saturday. First impressions overall is that it's very promising. 

I only have a few real gripes:
1) One is the delay from changing settings. Sometimes it takes a bit for the software to recognize my commands. I'm using the software on a very capable computer, too.
I allso tried it on my netbook and the screen resolution is too large to fit in the 800x600 screen, so I have to change the default settings to allow me to scroll the GUI and access all the features. I believe I saw where they are fixing this, though? 

2) Also, I notice that when I save the settings the board, the 'refresh' symbol is deactivated, and the only way to active it is to 'x' out the air program notifier (which tells you the status of the board/comm). When I do this, it sh uts off communication to the baord. It seems that whenever I save the settings, that's all I can do unless I close and reopen the software. This could be a glitch on my end, but I've noticed it happens with both the 2.1 and the 4-way PEQ versions.

3) They said it can't be done, but if there's ANY way to be able to control both boards at the same time that would be fantastic. I can speak from experience that switching between GUI's is going to have some ill effects when setting up a system. Though, I think at this price point, it's something that can be lived with.

As far as pre-in/out voltage:
Pre-in Voltage:
I played pink noise FULL TILT on my headunit and watched the input meters. They never once came even close to clipping. This was out of the bitone’s output, with a 60hz tone on the subwoofer channel, and the bitone’s outputs are rated for 8v out. Regarding input voltage, I think we’ll all be just fine. And again, you have an input voltage meter you can watch if you’re really worried about it.

Pre-out voltage: 
This one is a bit more tricky. Long story short is that I had to readjust my bitone’s software output level to about 4dB on the subwoofer channel after using this guy in my car. What does that mean? Simply that I would have had to jack the gains up quite a bit. I meant to take actual voltage measurements but honestly got so caught up in everything else that I forgot to take a final measurement.
Bottom line: The low preout voltage resulted in a sound that was noticeably weaker. 
So, if you guys are worried about cranking the gains on your amps and inducing more noise floor, you might want to purchase a line driver. 


I'm going to try to write up a review for it in the next couple of days. I need to take a few screenshots of the software to add to the review and take a few macro shots of the board for those who want to see the hardware components.

The overall impression: 
Two of the boards (for up to 8 channel processing), with both the 4-way P-EQ and Graphic EQ plug-ins, retails at $220+shipping. That's KILLER pricing. 
Buy a delayed turn on circuit for $20 (to prevent turn on pop), and a decent line driver (if needed) and I think for under $300 a person could have a very nice setup. One might also want to purchase a USB car adapter, too, which will make it easier on wiring and also solve ground loop issues.

- Erin


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## ErinH (Feb 14, 2007)

New plug-in versions released today. Looks like some of your requests were answered and they may have addressed my concerns with the GUI. 
Now that the new version is out, I'm going to take screenshots tonight and try to get the review up by the end of the week. 

- Increased choice of filter orders for Butterworth filters (6 to 48dB/oct in 6dB increments) and Linkwitz Riley (12 to 48dB/oct)
- 2way plug-ins now include full BandPass filters (LPF + HPF) on each output
- Low Shelf/High Shelf or Peak EQ now selectable for the both input and output PEQ bands
- Updated user interface for smaller screen resolution and faster refresh time


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## Melodic Acoustic (Oct 10, 2005)

bikinpunk said:


> New plug-in versions released today. Looks like some of your requests were answered and they may have addressed my concerns with the GUI.
> Now that the new version is out, I'm going to take screenshots tonight and try to get the review up by the end of the week.
> 
> - Increased choice of filter orders for Butterworth filters (6 to 48dB/oct in 6dB increments) and Linkwitz Riley (12 to 48dB/oct)
> ...


Nice, very nice.


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## jsun_g (Jun 12, 2008)

That is awesome to hear. It sounds like they have a strong focus on customer input for features, something you wouldn't get with a large manufacturer.

Sorry if I missed it, but are you powering this right off your car's +12v or using a power supply/conditioner?



bikinpunk said:


> New plug-in versions released today. Looks like some of your requests were answered and they may have addressed my concerns with the GUI.
> Now that the new version is out, I'm going to take screenshots tonight and try to get the review up by the end of the week.
> 
> - Increased choice of filter orders for Butterworth filters (6 to 48dB/oct in 6dB increments) and Linkwitz Riley (12 to 48dB/oct)
> ...


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## ErinH (Feb 14, 2007)

cigarette lighter USB adapter for power.


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## Hillbilly SQ (Jan 26, 2007)

bikinpunk said:


> cigarette lighter USB adapter for power.


And you could always go in behind the lighter to get power for a cleaner look. Hell my truck has one that can be turned on and off with the key so that would be a perfect place to wire into and it's easy to get back there

As for a linedriver for those that really think it's necessary is the Tru unit about the only somewhat reasonably priced one out these days? My PG tld66 did what I needed it to do but it still left a lot to be desired...but what do you expect for $60 shipped off fleabay?

As for the noise floor have you had a chance to play with your gains and maybe take the BitOne.1 out of the chain to see what happens? I lowered my noise floor a lot switching to the 880 and if this thing is going to hiss like a mofo it might be a big downer for a lot of us especially those of us (like me) that listens at lower volumes half the time or more...and hiss that overpowers road noise is simply unacceptable. How about trying it in Lindsey's car if you havn't already?


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## eficalibrator (Aug 25, 2005)

Just a silly question, but why bother running multiple cables/adaptors to go from a cigarette lighter adaptor to USB-A (large) then another cable for USB-A to USB-B (mini)? Would it be better to just cannibalize something simpler like this and just solder in +/- wires directly from the adaptor to the same fuse block as the rest of the amps.


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## TokoSpeaker (Nov 12, 2010)

Nice Job, Masswork!
Congratz..


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