# REW - House Curve Files



## fcarpio

As far as I understand, these files are basically a csv format file with the values of the house curve in a way that REW can read it. Once read by REW it will show up on the screen so we can use it as a reference for tuning out systems. With that said, does anyone here have such House Curve files that would like to share? If so, please copy and paste them here. Worst case scenario I will create my own based on the well known House Curves for car audio and I will share them here.


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## fcarpio

So far I have created a curve file, I used the JBL as the model for this one. Here it is:

20 9.2
25 9.2 
32 9.2
40 9.2
50 9.2
63 9.2
80 8.0
100 6.0
125 4.0
160 1.0
200 0.0
250 0.0
315 0.0
400 0.0
500 0.0
630 0.0
800 0.0
1000 0.0
1250 0.0
1600 0.0
2000 0.0
2500 0.0
3150 0.0
4000 -0.5
5000 -1.0
6300 -2.0
8000 -3.0
10000 -4.0
12500 -4.5
16000 -5.0
20000 -6.0

But I can't find the way to make it show up on the screen. I got to load it in the House Curve options but I cant find the House Curve icon to make it show up on the screen. Any help will be greatly appreciated.


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## XR250rdr

I added your curve to a text file and opened it with REW. It shows up as the target in the EQ window automatically.








[/IMG]


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## fcarpio

XR250rdr said:


> I added your curve to a text file and opened it with REW. It shows up as the target in the EQ window automatically.
> 
> 
> 
> 
> 
> 
> 
> 
> [/IMG]


Got it, thank you.


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## JVD240

Can't you just omit the 200Hz - 3.15kHz?

I thought that's how it worked.


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## strohw

It is. You can write it this way:


20 9.2
63 9.2
80 8.0
100 6.0
125 4.0
160 1.0
200 0.0
3150 0.0
4000 -0.5
5000 -1.0
10000 -4.0
12500 -4.5
16000 -5.0
20000 -6.0


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## Beckerson1

Sub'd


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## Justin Zazzi

Have you seen the excel tool I build specifically for building house curves? The link in my signature below is for the most recent version.


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## gijoe

I haven't used this in REW yet. Anyone care to give a quick summary of how this feature works?


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## XR250rdr

gijoe said:


> I haven't used this in REW yet. Anyone care to give a quick summary of how this feature works?


It allows you to define an EQ target curve that is more complex than the standard target curve functionality in the EQ window.

Jazzi has an excel sheet that allows you to build a house curve and export a text file that REW can read. The file is loaded in the House Curve tab in Settings.


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## gijoe

XR250rdr said:


> It allows you to define an EQ target curve that is more complex than the standard target curve functionality in the EQ window.
> 
> Jazzi has an excel sheet that allows you to build a house curve and export a text file that REW can read. The file is loaded in the House Curve tab in Settings.


Ok, then what? Do you just display the curve along with the FR of your system and make notes of what cuts need to be made? I guess I'll have to play with it a bit to see why it would be useful. Couldn't I just look at my FR and say "look, it needs to be 5dB down from x to y?"


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## subterFUSE

Jazzi said:


> Have you seen the excel tool I build specifically for building house curves? The link in my signature below is for the most recent version.


Jazzi did a really great job with his House Curve tool. You can customize anything you want and then export it to a text file.


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## XR250rdr

gijoe said:


> Ok, then what? Do you just display the curve along with the FR of your system and make notes of what cuts need to be made? I guess I'll have to play with it a bit to see why it would be useful. *Couldn't I just look at my FR and say "look, it needs to be 5dB down from x to y?"*


REW has an auto EQ function. It will generate filters to adjust the measured FR to meet your target curve. With some EQs you can send filters directly to the EQ.

Yes, of course you can.


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## oabeieo

The auto eq works very nice.!! 

Sometimes playing with its limits can get a better tune. But for the MOST part it works with no changes. The help file on minidsp site is very good about it . Got me to really understand how to use all of its features


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## gijoe

XR250rdr said:


> REW has an auto EQ function. It will generate filters to adjust the measured FR to meet your target curve. With some EQs you can send filters directly to the EQ.
> 
> Yes, of course you can.


I just want to make sure I understand. If you plug in a curve does it tell you what to adjust in order to make your FR match the target curve? I guess I just need to spend some time playing with this feature.


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## subterFUSE

gijoe said:


> I just want to make sure I understand. If you plug in a curve does it tell you what to adjust in order to make your FR match the target curve? I guess I just need to spend some time playing with this feature.


Yes, it will generate suggested EQ settings to match the target curve.


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## High Resolution Audio

subbed


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## fcarpio

Jazzi said:


> Have you seen the excel tool I build specifically for building house curves? The link in my signature below is for the most recent version.


Awesome, thank you! I will try your spreadsheet soon...


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## fcarpio

So I have tried the JBL curve and even though it was a vast improvement over my ear tune I though it was a bit too mellow for my taste. I think now I am going to try something with a little more sparkle like the Crutchfield house curve:

20 6.0
25 6.0
32 6.0
40 6.0
50 6.0
63 6.0
80 6.0
100 6.0
125 5.0
160 3.0
200 2.0
250 0.0
315 0.0
400 1.0
500 0.0
630 0.0
800 0.0
1000 0.0
1250 0.0
1600 0.0
2000 0.0
2500 0.0
3150 0.0
4000 0.0
5000 0.0
6300 0.0
8000 0.0
10000 -1.0
12500 1.5
16000 -2.0
20000 -9.0

I know I can get rid of all the zeroes but that is my template for more curves to come.


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## subterFUSE

12500 should be -1.5?


Sent from my iPad using Tapatalk


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## fcarpio

subterFUSE said:


> 12500 should be -1.5?
> 
> 
> Sent from my iPad using Tapatalk


Good catch but no, that is the way that curve is:


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## EmptyKim

fcarpio said:


> Good catch but no, that is the way that curve is:



I like the graphs for comparison. I assume you've tried these or these curves were your reference points to try a different curve?


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## fcarpio

EmptyKim said:


> I like the graphs for comparison. I assume you've tried these or these curves were your reference points to try a different curve?


So far I have only tried the JBL curve, now I will try the Crutchfield curve. Eventually I hope to try them all and save as presets to see which one I like more.


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## Mic10is

try 20hz at 9db with a gradual downward slope to 180hz. then flat from 180 to 20k

I dont know why people cut the top end, thats where a sense of air around instruments and music resides. add to the realism.


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## fcarpio

Mic10is said:


> try 20hz at 9db with a gradual downward slope to 180hz. then flat from 180 to 20k
> 
> I dont know why people cut the top end, thats where a sense of air around instruments and music resides. add to the realism.


Thanks, I will try that.

Edit: something like this?


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## Mic10is

fcarpio said:


> Thanks, I will try that.
> 
> Edit: something like this?


thats still sloping downward to 20k.
I'm talking FLAT from 160 or 200 to 20k

minus any natural dips in response which shouldnt be boosted


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## fcarpio

Strange, the file is set to 0db from 200hz to 20khz. I must be doing something wrong.


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## Justin Zazzi

REW, for whatever reason, has some frustrating default settings in the EQ module. Look at the "Target Settings" section, and change the fields labeled "LF Rise Slope" and "HF Fall Slope" from 1.8 to zero. Unfortunately you have to do this every time. I don't know how to make it default to zero.


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## XR250rdr

Jazzi said:


> REW, for whatever reason, has some frustrating default settings in the EQ module. Look at the "Target Settings" section, and change the fields labeled "LF Rise Slope" and "HF Fall Slope" from 1.8 to zero. Unfortunately you have to do this every time. I don't know how to make it default to zero.


Target Defaults are under the Equalizer tab in Preferences.


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## Justin Zazzi

Whaaaaat!? Nice, thank you!


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## Babs

Mic10is said:


> try 20hz at 9db with a gradual downward slope to 180hz. then flat from 180 to 20k
> 
> I dont know why people cut the top end, thats where a sense of air around instruments and music resides. add to the realism.






Mic10is said:


> thats still sloping downward to 20k.
> 
> I'm talking FLAT from 160 or 200 to 20k
> 
> 
> 
> minus any natural dips in response which shouldnt be boosted



I'm gonna try that with the next tune. The Mic Tune!
Much work to do until then though. 
Back to the basement.


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## Elgrosso

Here's the mp1 curve from Raimonds Skuruls / APL, converted to REW by Hanatsu:

https://www.dropbox.com/s/fz65hbe9ccmixb1/jbl_APL.txt?dl=0










It's my baseline now


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## fcarpio

XR250rdr said:


> Target Defaults are under the Equalizer tab in Preferences.


Awesome, it worked. Thank you!!!


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## Mic10is

Not "my" tune. It's something I learned from several people over the years. Keep in mind "flat" doesn't mean flat. Don't boost dips . People typically have a harder time hearing a dip than a peak. And the dip is there for a reason.identify why before trying to boost to add it back in which usually won't work


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## fcarpio

Mic10is said:


> Not "my" tune. It's something I learned from several people over the years. Keep in mind "flat" doesn't mean flat. Don't boost dips . People typically have a harder time hearing a dip than a peak. And the dip is there for a reason.identify why before trying to boost to add it back in which usually won't work


Is there a section in REW where you can give it a criteria to not to boost dips?


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## Babs

fcarpio said:


> Is there a section in REW where you can give it a criteria to not to boost dips?



Yes. You can set individual gain max and overall gain max. Set individual to no more than 1 or 0db and max at 0db. 

Also once you do the auto EQ and it generates curves, you can mess with those as well, and tweak them, or even add another if there's a peak that you want to address that REW didn't knock down. 

Don't be afraid to play with the EQ tool. The more you do the better you'll get and you can constantly move your target or shape it's slope and re-run with a goal of finding the best set of minimal EQ trims to achieve the line you want. Varying the level of the target just by a db or two +- can have a big effect.

Example, you can load up a custom curve file, set the roll off points at 200hz and if you increase both slopes you can essentially change the slope of the entire curve evenly. 

As you get the hang of it, you can really make the target curve do whatever you like. 

I do emphasize though what's your main goal for individual drivers though is not necessarily matching a curve just yet, but balancing the sides and basically knocking down the sharp peaks, leaving the dips as Mic pointed out that are car-induced. 

My order after crossover work:
1-individual drivers
2-TA
3-pairs EQ
4-EQ by ear in 1/3 increments with 1/3 octave noise to center it up 
5-finally overall curve shaping and any overall peaks. 
6-enjoy


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## fcarpio

Babs said:


> Yes. You can set individual gain max and overall gain max. Set individual to no more than 1 or 0db and max at 0db.
> 
> Also once you do the auto EQ and it generates curves, you can mess with those as well, and tweak them, or even add another if there's a peak that you want to address that REW didn't knock down.
> 
> Don't be afraid to play with the EQ tool. The more you do the better you'll get and you can constantly move your target or shape it's slope and re-run with a goal of finding the best set of minimal EQ trims to achieve the line you want. Varying the level of the target just by a db or two +- can have a big effect.
> 
> Example, you can load up a custom curve file, set the roll off points at 200hz and if you increase both slopes you can essentially change the slope of the entire curve evenly.
> 
> As you get the hang of it, you can really make the target curve do whatever you like.
> 
> I do emphasize though what's your main goal for individual drivers though is not necessarily matching a curve just yet, but balancing the sides and basically knocking down the sharp peaks, leaving the dips as Mic pointed out that are car-induced.
> 
> My order after crossover work:
> 1-individual drivers
> 2-TA
> 3-pairs EQ
> 4-EQ by ear in 1/3 increments with 1/3 octave noise to center it up
> 5-finally overall curve shaping and any overall peaks.
> 6-enjoy


Thanks! That is going to keep me busy for a while.


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## Babs

fcarpio said:


> Thanks! That is going to keep me busy for a while.


Yep.. Trick is, house curve IMHO is way way down the line as part of the end game of tonality. The foundational stuff upfront with fixing peaks etc is where the rubber meets the road.

At the onset, make left look like right including crossover slopes and tops, knock down the peaks, etc.. General leveling so left=right, etc. Keep in mind also, even if your timing is dialed on point with every driver, you can have individual drivers that plot beautifully individually, then the car environment gets involved when they're measured playing together with mono noise. So it's iterative.. You only have to have "balance" (left=right) done nicely before TA. 

Also this will keep you busy. 
https://www.youtube.com/playlist?list=PL8DsRfMp9q4az_gei9C27aRyUIUvMIMO0


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## EmptyKim

Babs said:


> Yes. You can set individual gain max and overall gain max. Set individual to no more than 1 or 0db and max at 0db.
> 
> *Also once you do the auto EQ and it generates curves, you can mess with those as well, and tweak them, or even add another if there's a peak that you want to address that REW didn't knock down.
> 
> Don't be afraid to play with the EQ tool. The more you do the better you'll get and you can constantly move your target or shape it's slope and re-run with a goal of finding the best set of minimal EQ trims to achieve the line you want. Varying the level of the target just by a db or two +- can have a big effect.
> *
> Example, you can load up a custom curve file, set the roll off points at 200hz and if you increase both slopes you can essentially change the slope of the entire curve evenly.
> 
> As you get the hang of it, you can really make the target curve do whatever you like.
> 
> I do emphasize though what's your main goal for individual drivers though is not necessarily matching a curve just yet, but balancing the sides and basically knocking down the sharp peaks, leaving the dips as Mic pointed out that are car-induced.
> 
> My order after crossover work:
> 1-individual drivers
> 2-TA
> 3-pairs EQ
> 4-EQ by ear in 1/3 increments with 1/3 octave noise to center it up
> 5-finally overall curve shaping and any overall peaks.
> 6-enjoy


Thanks. These are some good points. Looking forward to my next tuning session.


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## Babs

EmptyKim said:


> Thanks. These are some good points. Looking forward to my next tuning session.


Glad to help.. Keep in mind like Mic said, whatever tool such as REW you use, general good principles of EQ apply.. cuts only if possible and try to avoid attempting huge small-Q narrow cuts (might be a good principle, I just kinda figured that'd be wise). Be subtle in your EQ because you're gonna see that curve change anyway when you go from 1 to more drivers. I've seen a place that was a peak become a dip when both were playing. It gets a bit wonky in car. Even if TA is spot on.

"For cars, we're tuning inside the speaker cabinet, rather than tuning the room."
.. someone said.


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## fcarpio

Babs said:


> Yep.. Trick is, house curve IMHO is way way down the line as part of the end game of tonality. The foundational stuff upfront with fixing peaks etc is where the rubber meets the road.
> 
> At the onset, make left look like right including crossover slopes and tops, knock down the peaks, etc.. General leveling so left=right, etc. Keep in mind also, even if your timing is dialed on point with every driver, you can have individual drivers that plot beautifully individually, then the car environment gets involved when they're measured playing together with mono noise. So it's iterative.. You only have to have "balance" (left=right) done nicely before TA.
> 
> Also this will keep you busy.
> https://www.youtube.com/playlist?list=PL8DsRfMp9q4az_gei9C27aRyUIUvMIMO0


Subscribed to your YouTube channel!


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## Babs

A word about roll-off (then I'll shut up.. promise  )...

I'm with Mic again that I believe purposely rolling off the highest of highs will hurt your "sparkle" at the top.. That last little bit of air and detail. I do like a bit of "overall" slope personally but I'm for letting good detailed amps and tweeters do their thing.

That said, folks should realize, if measuring with RTA and a moving mic averaging it's even more so, but I imagine even with sweeps in the measurement screen, even the better mics (and many of us are using $100 umik-1's or daytons etc), will have a roll-off in their response.

So take everything from 8k up with a grain of salt in your measurements unless you're using some really solid mic gear. Subterfuse feel free to weigh in on that as I know you've delved into that quite a bit. 

So certainly when approaching your tweeters, consider really is that a sure-enough peak that needs addressing at 10k or just a point where the microphone falls on it's face, and should I really cut it at 4db? Approach with caution or there be dragons there and you could really lose some nice 'air'.

K.. Shutting up now, cuz I fear the loudest mouth in this thread knows the least. LOL!


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## fcarpio

Update: I made some of the recommended changes, including disabling the roll off and using the mic curve and setting gains first and it now sounds much better. Still a work in progress but I am much happier with the results now.


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## Justin Zazzi

Babs said:


> That said, folks should realize, if measuring with RTA and a moving mic averaging it's even more so, but I imagine even with sweeps in the measurement screen, even the better mics (and many of us are using $100 umik-1's or daytons etc), will have a roll-off in their response.


One more reason to grab a calibrated microphone from cross-spectrum labs  I compared the $75 Dayton mic I bought there and with the calibration file it measures almost exactly the same as the $700 ruler-flat mic I picked up recently from Earthworks. Super impressed!


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## Babs

Jazzi said:


> One more reason to grab a calibrated microphone from cross-spectrum labs  I compared the $75 Dayton mic I bought there and with the calibration file it measures almost exactly the same as the $700 ruler-flat mic I picked up recently from Earthworks. Super impressed!



Yeah I kinda hope my cross-spectrum UMIK-1 is as good. Seems so.


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## Elgrosso

Babs said:


> Yeah I kinda hope my cross-spectrum UMIK-1 is as good. Seems so.


At least they are consistent, I recently got a new umik from cross-spectrum, and I get the same results than with my old umik from minidsp (both with their cal file of course).
So same manufacturer but from totally different batch.
But the cross-spectrum cal is fancier, more angles, pdf to explain etc


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## fcarpio

OK, so after a few hiccups I got my system going 100% again. I have messed with Mic10's curve using REW's AutoEQ and in my system it turned out a bit too bright. Tonight I tried JBL's curve and it was too dull. I think I am going to have to come up with my own curve to find that sweet median. Right now I am using Mic10's curve with the tweeters dialed down a bit and it sounds pretty good. I would leave it like that but I am OCD and I know that curve is not smooth (LOL), that is why I am coming up with my own. I think I am going to average Mic10's and JBL's in excel to get what I want and give it a try.


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## Drop11

Idk know what dsp you are using but I'm looping back through mine so I can have left/right eq and then a master eq. Once the system is tuned the master eq makes changing curves trivial.


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## sqnut

Mic10is said:


> I dont know why people cut the top end, thats where a sense of air around instruments and music resides. add to the realism.


umm... maybe because our ears are 2-3' from the tweeter in a highly reflective environment, i.e. there is no natural attenuation of the highs, that you would get if you sat 18' from your speakers in a room....


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## fcarpio

Drop11 said:


> Idk know what dsp you are using but I'm looping back through mine so I can have left/right eq and then a master eq. Once the system is tuned the master eq makes changing curves trivial.


Please elaborate. I am using the Alpine pxa - h800.


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## Drop11

fcarpio said:


> Drop11 said:
> 
> 
> 
> Idk know what dsp you are using but I'm looping back through mine so I can have left/right eq and then a master eq. Once the system is tuned the master eq makes changing curves trivial.
> 
> 
> 
> Please elaborate. I am using the Alpine pxa - h800.
Click to expand...

I'm running a jl twk. Ins and outs shouldn't be to different.
1st off can you split channels inside the Alpine unit? 


Basically I had inputs and outputs not being used on the dsp. 
I run left/right inputs normally into the dsp, eq to a basic curve then run the outputs of these channels back into the dsp on channels 3 and 4 then run the outputs from 3/4 to the amps. My dsp allows me to send as many channels as I want through the same eq so I just send channels 3/4 through what I call the master eq. Knowing what my base curve is I can just draw the response curve I want with the master eq and voila done. 
For now Im leaving the sub out of the equation. I can loop it back through the same to the same eq If I choose.

The jl unit allows me to run as many channels through the same eq as I want. It has a slick routing matrix that allows for some pretty neat stuff to happen.

I've never used the Alpine unit but as long as you can run multiple channels through the same eq without it actually combining the signals you should be good.

Things to consider. If your unit is noisy doing this will increase the noise. I was able to loop twice, that 3 sets of eq with zero noise. 
Second concern would be timing. Processors take time to calculate and output the signal. Mine was less than 1/10 of a millisecond. Very impressive, I can't imagine the Alpine being very far off from that.
If you can configure the Alpine to do this it's worth it. Even if you just do it long enough to find the curve you want it makes things very easy.
If you are doing a bigger system and only have say, 2 channels open, you could use the first eqs as the master the either branch out from there or use splitters to separate the outputs into more input channels.


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## Jscoyne2

You use a curve to match l/r and crossovers. The reason most curves are heavy on the bottom end and light on the top end is because our ears are very sensitive to high frequencies and not very sensitive to low frequencies. So we have to play low freq loudly to hear them. We play high frequencies quieter because we pick them up easier. If you had a graph of what we were hearing acoustically when tuned (assuming perfectly tuned) to general house curves. Itd be completely flat. 

Because every car has different reflections. One house curve will not work for every car. You simply use it as a baseline for matching l/r and then you tune for taste from there. 

Sent from my SGH-T999 using Tapatalk


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## fcarpio

Drop11 said:


> I'm running a jl twk. Ins and outs shouldn't be to different.
> 1st off can you split channels inside the Alpine unit?
> 
> 
> Basically I had inputs and outputs not being used on the dsp.
> I run left/right inputs normally into the dsp, eq to a basic curve then run the outputs of these channels back into the dsp on channels 3 and 4 then run the outputs from 3/4 to the amps. My dsp allows me to send as many channels as I want through the same eq so I just send channels 3/4 through what I call the master eq. Knowing what my base curve is I can just draw the response curve I want with the master eq and voila done.
> For now Im leaving the sub out of the equation. I can loop it back through the same to the same eq If I choose.
> 
> The jl unit allows me to run as many channels through the same eq as I want. It has a slick routing matrix that allows for some pretty neat stuff to happen.
> 
> I've never used the Alpine unit but as long as you can run multiple channels through the same eq without it actually combining the signals you should be good.
> 
> Things to consider. If your unit is noisy doing this will increase the noise. I was able to loop twice, that 3 sets of eq with zero noise.
> Second concern would be timing. Processors take time to calculate and output the signal. Mine was less than 1/10 of a millisecond. Very impressive, I can't imagine the Alpine being very far off from that.
> If you can configure the Alpine to do this it's worth it. Even if you just do it long enough to find the curve you want it makes things very easy.
> If you are doing a bigger system and only have say, 2 channels open, you could use the first eqs as the master the either branch out from there or use splitters to separate the outputs into more input channels.


I see what you are doing and it is pretty cool. My MiniDSP allowed for that but it never occurred to me to use it that way. With some trickery I could get my alpine to do it, but honestly I don't see the need (I may be wrong here) as I shoot for the curve I want, no need to lay one on top of the other. Like you said, there is also a chance of me adding noise by looping the signal like that. Am I going to try it? Hell yes! Just for ****s and giggles.


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## subterFUSE

What you guys are describing is one of the major advantages of Pro Audio DSP vs. car audio.

That is.... having separate EQ and XOver available on both the input side and the output side.


Some of the car DSPs are beginning to catch on to this... for example, the Helix DSP Pro now offers 5 band parametric input EQ, but unfortunately it is only on the Analog inputs. Won't work on Digital. And it's only EQ, not XOvers.


Anyway, the theory with the Pro Audio DSPs having this is simple.... For many sound engineers they will be working with a mobile touring rig. They use the same speakers but the room changes constantly. With separate EQ and XOver banks, they can tune the speakers on the output side and leave that alone. Then they can tune the room on the input side when they get to the venue.

In the car, you could theoretically use the output processing to flatten out your response and then use the Input EQ to adjust tonality of the overall system to your taste. And this can be done without upsetting the Left to Right balance you achieved on the Output EQ.



There is also another, less-well-known benefit and this has to do with crossovers and phase rotation.

If you assume a typical 2 way crossover between a midrange and tweeter, one speaker will have a high pass and the other a low pass. Simple enough.... Now, let's say you adjust those XOver settings and the timing and you get nice flat summation through your crossover region. For this example let's say your tweeter is crossed over at 3000Hz. Again, simple enough.

Now, you need to put a high pass on that midrange speaker to make it blend with the midbass. For example, let's say you put a high pass at 400Hz on the mid. So you add that high pass filter to the mid, and suddenly your nice flat summation through the tweeter crossover gets distorted. What happened?

When you put that high pass filter on the mid at 400Hz, you added phase rotation that is now affecting the upper range of that driver. It's now influencing the low pass with that tweeter at 3000Hz. Now what do we do?

Well, if you have a Pro Audio DSP the solution is actually very simple.

Instead of adding that high pass 400Hz filter to the output for that midrange speaker, put that 400Hz filter on the INPUT for both the midrange and the tweeter. Now both the mid and tweeter will be getting the same high pass filter applied to them with the same crossover-induced phase rotation. The effect? Your 3000Hz crossover region now goes back to the nice flat summation you had before. Since the 400Hz filter is applied to both the mid and tweeter, it's effectively nullified.

I'm really hoping as more car audio DSPs come to market they begin incorporating more of the Pro-Audio features like full Input and Output processing.


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## Babs

subterFUSE said:


> What you guys are describing is one of the major advantages of Pro Audio DSP vs. car audio.
> 
> That is.... having separate EQ and XOver available on both the input side and the output side.
> 
> 
> Some of the car DSPs are beginning to catch on to this... for example, the Helix DSP Pro now offers 5 band parametric input EQ, but unfortunately it is only on the Analog inputs. Won't work on Digital. And it's only EQ, not XOvers.
> 
> 
> Anyway, the theory with the Pro Audio DSPs having this is simple.... For many sound engineers they will be working with a mobile touring rig. They use the same speakers but the room changes constantly. With separate EQ and XOver banks, they can tune the speakers on the output side and leave that alone. Then they can tune the room on the input side when they get to the venue.
> 
> In the car, you could theoretically use the output processing to flatten out your response and then use the Input EQ to adjust tonality of the overall system to your taste. And this can be done without upsetting the Left to Right balance you achieved on the Output EQ.
> 
> 
> 
> There is also another, less-well-known benefit and this has to do with crossovers and phase rotation.
> 
> If you assume a typical 2 way crossover between a midrange and tweeter, one speaker will have a high pass and the other a low pass. Simple enough.... Now, let's say you adjust those XOver settings and the timing and you get nice flat summation through your crossover region. For this example let's say your tweeter is crossed over at 3000Hz. Again, simple enough.
> 
> Now, you need to put a high pass on that midrange speaker to make it blend with the midbass. For example, let's say you put a high pass at 400Hz on the mid. So you add that high pass filter to the mid, and suddenly your nice flat summation through the tweeter crossover gets distorted. What happened?
> 
> When you put that high pass filter on the mid at 400Hz, you added phase rotation that is now affecting the upper range of that driver. It's now influencing the low pass with that tweeter at 3000Hz. Now what do we do?
> 
> Well, if you have a Pro Audio DSP the solution is actually very simple.
> 
> Instead of adding that high pass 400Hz filter to the output for that midrange speaker, put that 400Hz filter on the INPUT for both the midrange and the tweeter. Now both the mid and tweeter will be getting the same high pass filter applied to them with the same crossover-induced phase rotation. The effect? Your 3000Hz crossover region now goes back to the nice flat summation you had before. Since the 400Hz filter is applied to both the mid and tweeter, it's effectively nullified.
> 
> I'm really hoping as more car audio DSPs come to market they begin incorporating more of the Pro-Audio features like full Input and Output processing.


Mind = blown 

Would it be prudent then simply to re-align phase, of either the tweeters or the mids in your example, with phase adjustment (which is an all-pass filter in our Helix)? 

A good test for that would be bypassing the mid HPF briefly, aligning mid/tweet with their respective crossover filters (LP mid, HP tweet) CAREFULLY just with filtered PN in the mid/tweet crossover region, then activating the HPF on the mid and checking mid/tweet transition again. You can bet I'm gonna try that and see it for myself. :beerchug: 

Might even take that experiment further and test how different order crossovers and slopes on the mid HP affect phase coherence in the mid/tweet transition.


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## Drop11

Whoa. You just game me an idea.
With the extra channels I have I can split the channels and put a crossover say at 200hz. High pass on one channel, low on the other. 
Then I can recombine the channels and alter the crossover types to change phase.
Not that I need it but it seems like it could be fun. I also have huge peaks at 200hz and can spread the points out like we do subs and use the crossover to omit unwanted buildup as well as correct phase fRon the huge cuts I normally have to make with the eq. Hmmm


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## fcarpio

If I wanted to roll off the highs, which frequency should I start at? How many dbs per octave? Just want a starting point to play with.


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## EmptyKim

fcarpio said:


> If I wanted to roll off the highs, which frequency should I start at? How many dbs per octave? Just want a starting point to play with.


Have you looked at these:
http://www.diymobileaudio.com/forum/1828201-post16.html


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## Drop11

fcarpio said:


> If I wanted to roll off the highs, which frequency should I start at? How many dbs per octave? Just want a starting point to play with.


I BARELY roll off my highs. As in down 2db at 10khz.
Most people start rolling off at around 2khz.

This is something you will have to adjust to taste. This is what will define wether or not you have a bright, neutral or smooth top end. Keep your overall response smooth but adjust this rolloff to what you like.
Keep in miND a little goes a long way.
Start with a 1db per octave rolloff and see how you like it. If it's still too bright try another .5db. Take small steps here. There is going to be a sweet spot for YOU!

I tend to knock everything between 800hz and 3.5khz down a db or 2. These frequencies are irritating to me and are responsible for most of the harshness in a system.


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## Justin Zazzi

Drop11 said:


> I tend to knock everything between 800hz and 3.5khz down a db or 2. These frequencies are irritating to me and are responsible for most of the harshness in a system.


This right here. If you look at the equal-loudness curves at about 80 or 90 phons, you will see there is a valley around 2-4khz. This means we are more sensetive to those frequencies. When people talk about "rolling off" the high frequencies I wish they would try cutting this region first and leave all the 5khz+ information intact instead of cutting that too.


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## Drop11

Jazzi said:


> Drop11 said:
> 
> 
> 
> I tend to knock everything between 800hz and 3.5khz down a db or 2. These frequencies are irritating to me and are responsible for most of the harshness in a system.
> 
> 
> 
> This right here. If you look at the equal-loudness curves at about 80 or 90 phons, you will see there is a valley around 2-4khz. This means we are more sensetive to those frequencies. When people talk about "rolling off" the high frequencies I wish they would try cutting this region first and leave all the 5khz+ information intact instead of cutting that too.
Click to expand...

That's pretty much what I do. I love all the little subtle details in the verbs and delays up top. I cut just enough to keep it from being crunchy.

Fun fact. I CANNOT hear pure tones above 13khz but I can hear a .5 db change in tone at 18khz. Funny how that works.


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## fcarpio

Excellent, this is working well. Now I am getting more consistent results and I can tailor the curve to what I like. Thanks to all.


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## Babs

Drop11 said:


> That's pretty much what I do. I love all the little subtle details in the verbs and delays up top. I cut just enough to keep it from being crunchy.
> 
> Fun fact. I CANNOT hear pure tones above 13khz but I can hear a .5 db change in tone at 18khz. Funny how that works.



IID.. Why if you cut as much as .5db on one side at one freq it'll skew the image there in your tweeters. 


Sent from my iPad using Tapatalk


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## Drop11

fcarpio said:


> Excellent, this is working well. Now I am getting more consistent results and I can tailor the curve to what I like. Thanks to all.


You're just getting started. Once you get your curve you have months of tiny adjustments ahead of you if you have any ocd tendencies at all.
These small changes combine to make a big difference in clarity, depth and impact.


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## fcarpio

Do you guys add any smoothing to the curve before the autoeq? Does it matter?


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## FunkPnut

The amount of smoothing will effect the filter output of AutoEQ.

I just use variable smoothing, which is what is suggested on the REW website.


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## Drop11

I use 1/24 on my sub. Variable on everything else. Made a pretty substantial difference. If you are using a 1/3 OCTAVE EQ variable is fine. 
You can't really dig into a subs response with that. 
For instance I have 3 parametric filters making adjustments just between 30 and 40 hz. Some people may say it isn't needed but it makes a night and day difference to me.


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## fcarpio

FunkPnut said:


> The amount of smoothing will effect the filter output of AutoEQ.
> 
> I just use variable smoothing, which is what is suggested on the REW website.





Drop11 said:


> I use 1/24 on my sub. Variable on everything else. Made a pretty substantial difference. If you are using a 1/3 OCTAVE EQ variable is fine.
> You can't really dig into a subs response with that.
> For instance I have 3 parametric filters making adjustments just between 30 and 40 hz. Some people may say it isn't needed but it makes a night and day difference to me.


I'll give this a shot tonight. Thanks to both of you!


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## sqnut

Drop11 said:


> I tend to knock everything between 800hz and 3.5khz down a db or 2. These frequencies are irritating to me and are responsible for most of the harshness in a system.





Jazzi said:


>


The FM curves are only part of the story, so while the curves tell us that we are most sensitive in the 2-4khz range, it is important to note that we are about 10 phons more sensitive to 4khz than 1khz, I'm not sure a db or two cut is not going to suffice. Additionally, our sensitivity tails off rapidly past 4khz so the logical assumption would be, don't cut anything past 5khz. But wait, this is only part of the story.

One has to factor in what is happening in the car and how close we are to the speakers. On the first front, if you measure a typical car / install for combing, one will find that this typically kicks in around 800-1khz and gets progressively worse as we go to higher frequencies. The way our brain interprets this ton of early reflections is to make the incident sound seem louder at these frequency. The more the combing at a frequency the louder we will perceive it. 

Use the PN tracks and set 1khz and 4khz to the same measured loudness, lets say 80 db. Now go back and forth between the two frequencies, which one do you perceive as much louder? How much do you have to cut at 4khz to get at the same perceived loudness as 1khz? I bet it's more than a db or 2. With frequencies that are prone to combing, there is a big difference between measured loudness and perceived loudness.

Now, at 5khz and above is where you're getting the maximum combing and although our hearing is tailing off, we are also perceiving the sound as getting louder. Also keep in mind that we are sitting 2-3' from the tweeter, so there is no natural attenuation in the highs. In a room where you sit 15-18' from the speaker, measure the response at the speaker and then again at your ears. You will find that 18' away, the highs are a bit rolled off as sound attenuates over distance and you loose highs to things like absorption etc.


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## Pariah Zero

sqnut said:


> Use the PN tracks and set 1khz and 4khz to the same measured loudness, lets say 80 db.



Isn't it a bit less work to compare white noise vs. pink noise?

For the crowd that likes an infomercial: 





Sent from my iPhone using Tapatalk


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## Ziggyrama

sqnut said:


> The FM curves are only part of the story, so while the curves tell us that we are most sensitive in the 2-4khz range, it is important to note that we are about 10 phons more sensitive to 4khz than 1khz, I'm not sure a db or two cut is not going to suffice. Additionally, our sensitivity tails off rapidly past 4khz so the logical assumption would be, don't cut anything past 5khz. But wait, this is only part of the story.
> 
> One has to factor in what is happening in the car and how close we are to the speakers. On the first front, if you measure a typical car / install for combing, one will find that this typically kicks in around 800-1khz and gets progressively worse as we go to higher frequencies. The way our brain interprets this ton of early reflections is to make the incident sound seem louder at these frequency. The more the combing at a frequency the louder we will perceive it.
> 
> Use the PN tracks and set 1khz and 4khz to the same measured loudness, lets say 80 db. Now go back and forth between the two frequencies, which one do you perceive as much louder? How much do you have to cut at 4khz to get at the same perceived loudness as 1khz? I bet it's more than a db or 2. With frequencies that are prone to combing, there is a big difference between measured loudness and perceived loudness.
> 
> Now, at 5khz and above is where you're getting the maximum combing and although our hearing is tailing off, we are also perceiving the sound as getting louder. Also keep in mind that we are sitting 2-3' from the tweeter, so there is no natural attenuation in the highs. In a room where you sit 15-18' from the speaker, measure the response at the speaker and then again at your ears. You will find that 18' away, the highs are a bit rolled off as sound attenuates over distance and you loose highs to things like absorption etc.


This is great info. Thank you for posting this. I am currently tuning my tweeters and experiencing difficulties as I hear harshness which I am trying to narrow in on. I suspect it is somewhere around 3kHz -4kHz. This gives me an idea where to look first.


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## sqnut

Pariah Zero said:


> Isn't it a bit less work to compare white noise vs. pink noise?
> 
> For the crowd that likes an infomercial:
> 
> 
> 
> 
> 
> Sent from my iPhone using Tapatalk


Valid point, but again too much theory and not enough application. Technically white noise which has equal energy at each frequency should be better when we want to measure perceived loudness at 1 & 4khz, BUT how we hear and perceive all sounds including music, is much closer aligned to pink noise which is equal energy per octave .


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## sqnut

Ziggyrama said:


> This is great info. Thank you for posting this. I am currently tuning my tweeters and experiencing difficulties as I hear harshness which I am trying to narrow in on. I suspect it is somewhere around 3kHz -4kHz. This gives me an idea where to look first.


The typical 'harshness' that we hear in most cars has several components to it. Too much bite at 1.6-2.5 khz, too much grainy and abrasive sound from 3-4khz, too much in your face shouty, sibilant sound from excess of 6-8 khz, watch the 'aaah' at 12.5 and 16 khz makes the sound brittle. Harshness that we hear is a combination of these problems.


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## Ziggyrama

sqnut said:


> The typical 'harshness' that we hear in most cars has several components to it. Too much bite at 1.6-2.5 khz, too much grainy and abrasive sound from 3-4khz, too much in your face shouty, sibilant sound from excess of 6-8 khz, watch the 'aaah' at 12.5 and 16 khz makes the sound brittle. Harshness that we hear is a combination of these problems.


Thanks. If I had to categorize, I'd call it very sharp sound, very obvious in vocals, in last syllables ending with S sounds, high pitched, pointed. I will post the curves but that is the best I can describe it.


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## Pariah Zero

sqnut said:


> Valid point, but again too much theory and not enough application. Technically white noise which has equal energy at each frequency should be better when we want to measure perceived loudness at 1 & 4khz, BUT how we hear and perceive all sounds including music, is much closer aligned to pink noise which is equal energy per octave .



No argument; perceived loudness is a messy subject anyway, since we perceive loudness differently for pure sine waves vs anything else.


Sent from my iPhone using Tapatalk


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## Drop11

Pariah Zero said:


> sqnut said:
> 
> 
> 
> Valid point, but again too much theory and not enough application. Technically white noise which has equal energy at each frequency should be better when we want to measure perceived loudness at 1 & 4khz, BUT how we hear and perceive all sounds including music, is much closer aligned to pink noise which is equal energy per octave
> 
> 
> 
> 
> 
> 
> 
> .
> 
> 
> 
> 
> No argument; perceived loudness is a messy subject anyway, since we perceive loudness differently for pure sine waves vs anything else.
> 
> 
> Sent from my iPhone using
> 
> Tapatalk
Click to expand...

As its different person to person. Then to compound it even more we hear things differently as individuals at different volumes.
Fun fun.


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## Pariah Zero

Drop11 said:


> As its different person to person. Then to compound it even more we hear things differently as individuals at different volumes.
> Fun fun.


Yeah. My wife has hyperacusis: some frequencies are very "loud" and painful to her at fairly low SPL's: 65-70 dBA.

I'm kind of the opposite: I have congenital tinnitus, which gives me a biological noise floor o 70-75 dBA. I've never experienced silence, and I probably never will.

Sent from my iPhone using Tapatalk


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## Drop11

I didn't know the name for it but my mom is super sensitive to midbass. Sucks about the tinnitus. I don't have it yet but I've been working around power tools for 25 years.
When I wake up on the ride to work my system sounds amazing at low volume. By the time I get off it sounds quiet and the highs sound a little muted. 
Very annoying considering I work pretty much 7 days a week. I have to wait several hours after work on day I need to do any fine tuning before I can get started.


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## fcarpio

How did you measure your noise floor? I'd like to measure my tinnitus as well.


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## valow

First of all, Jazzi, thank you for the very awesome tool you built. It's been a life saver for sure.

Second, I have a ridiculously silly noobish question regarding slopes. You recommend using 24db octaves for each driver in your tool. I'm running Polk MM 6501 and DB 6501s active in my truck, and from what I can find they are 12 db/octave slopes. If I set the slope in my TwK to 24db L-R will I be doing any harm to the drivers? My subs are set to 24 db, but not the mids or the highs. Just looking for some clarity, and I do apologize for the general noobish question.

Thanks!


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## Justin Zazzi

valow said:


> First of all, Jazzi, thank you for the very awesome tool you built. It's been a life saver for sure.
> 
> Second, I have a ridiculously silly noobish question regarding slopes. You recommend using 24db octaves for each driver in your tool. I'm running Polk MM 6501 and DB 6501s active in my truck, and from what I can find they are 12 db/octave slopes. If I set the slope in my TwK to 24db L-R will I be doing any harm to the drivers? My subs are set to 24 db, but not the mids or the highs. Just looking for some clarity, and I do apologize for the general noobish question.
> 
> Thanks!


I'm glad you enjoy the tool! I'm always looking for feedback or suggestions on how to improve it or what to add next. Feel free to send me a PM or post in the thread for that in my signature anytime.

Your question is not noobish. There are no dumb questions, only dumb answers.

A steeper crossover slope should not cause *more* potential damage to any equipment, it should actually be more safe in terms of damaging a speaker.

The best way to set crossover slopes is to use a measurement microphone system that you have high confidence in. If that is not available, then you can make some educated guesses. If you know there is a crossover somewhere at 12dB/octave, and your goal is to have a 24dB/octave slope, then you can add a 2nd 12dB/octave filter on top of what you already have and they will sum together to become a 24dB/octave filter. For example, this is how the Linkwitz-Riley filter is built (a pair of 6dB/octave Butterworth filters cascaded together becomes a 12dB/octave LR filter).

Now there are a lot of small details involved in getting two filters to sum together like that, and you'll never end up with something "perfect" by estimating like this. However, you won't be able to do much better than "close enough" without the aid of a measurement system. This is exactly why some people swear that overlapping or leaving gaps between high-pass and low-pass filter frequencies works great for them, or using non-symmetrical slopes works great for them, because nothing is ever "smooth" or "flat" in a car installation and some amount of finesse is required to compensate for that.

So if you don't have a measurement system then feel free to experiment with crossover frequencies and slopes. Just make sure you're being reasonable and not asking a tweeter to high-pass at 400hz with a 6dB slope or something like that. I mean you could at very low volume for a short while just to see, but you know what I mean.

Have fun!


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## valow

Jazzi said:


> I'm glad you enjoy the tool! I'm always looking for feedback or suggestions on how to improve it or what to add next. Feel free to send me a PM or post in the thread for that in my signature anytime.
> 
> Your question is not noobish. There are no dumb questions, only dumb answers.
> 
> A steeper crossover slope should not cause *more* potential damage to any equipment, it should actually be more safe in terms of damaging a speaker.
> 
> The best way to set crossover slopes is to use a measurement microphone system that you have high confidence in. If that is not available, then you can make some educated guesses. If you know there is a crossover somewhere at 12dB/octave, and your goal is to have a 24dB/octave slope, then you can add a 2nd 12dB/octave filter on top of what you already have and they will sum together to become a 24dB/octave filter. For example, this is how the Linkwitz-Riley filter is built (a pair of 6dB/octave Butterworth filters cascaded together becomes a 12dB/octave LR filter).
> 
> Now there are a lot of small details involved in getting two filters to sum together like that, and you'll never end up with something "perfect" by estimating like this. However, you won't be able to do much better than "close enough" without the aid of a measurement system. This is exactly why some people swear that overlapping or leaving gaps between high-pass and low-pass filter frequencies works great for them, or using non-symmetrical slopes works great for them, because nothing is ever "smooth" or "flat" in a car installation and some amount of finesse is required to compensate for that.
> 
> So if you don't have a measurement system then feel free to experiment with crossover frequencies and slopes. Just make sure you're being reasonable and not asking a tweeter to high-pass at 400hz with a 6dB slope or something like that. I mean you could at very low volume for a short while just to see, but you know what I mean.
> 
> Have fun!


Hey thanks. Again, your tool is outright amazing.

I'm using REW with a MiniDSP UMIK-1. It's been great so far, and all measurements I'm taking are using pink noise going ear to ear. Seems to be fine. I think I'll give it a shot - I can set slopes on both the high and low pass for my mids. Currently this is how I'm set up.
Mids LP 80, HP 5000, Tweeters, HP 5000, Subs LP 80 with Infrasonic at 30 (I'm running 2 12s).

I'll certainly toy around with it tonight or tomorrow. It's windy here, so I might wait for a calm and warmer day.

I didn't think there would be "harm" to the system, more just what I can hear etc. I'd be happy to report back - but anything I should do different don't hesitate to tell me. I'm not only doing this to learn, but also share my learnings on things I discover.

Thanks again.


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## Justin Zazzi

valow said:


> Hey thanks. Again, your tool is outright amazing.
> 
> I'm using REW with a MiniDSP UMIK-1. It's been great so far, and all measurements I'm taking are using pink noise going ear to ear. Seems to be fine. I think I'll give it a shot - I can set slopes on both the high and low pass for my mids. Currently this is how I'm set up.
> Mids LP 80, HP 5000, Tweeters, HP 5000, Subs LP 80 with Infrasonic at 30 (I'm running 2 12s).
> 
> I'll certainly toy around with it tonight or tomorrow. It's windy here, so I might wait for a calm and warmer day.
> 
> I didn't think there would be "harm" to the system, more just what I can hear etc. I'd be happy to report back - but anything I should do different don't hesitate to tell me. I'm not only doing this to learn, but also share my learnings on things I discover.
> 
> Thanks again.


Oh, fantastic. Since you have some good measurement tools then you can make full use of the curves that my excel tool will export. Look for my how-to posts inside the tool's thread to see all the steps. Essentially you want to match the acoustic response of your individual speakers to the individual curves that my tool exports. Then you will assure the crossover alignments are correct. To do this, you can use a combination of whatever processing you have available. Most people like to use a single piece of hardware to do all the processing such as a DSP, and set all the other pieces of equipment to "flat" or "bypass" mode such as the head unit, amplifiers, etc.

After you do the above and also set time alignment using a tape measure, try playing just the left side midrange and subwoofer together while inverting the polarity of the midbass and measure what you get. You should see a deep valley at the crossover frequency if everything is just right. You can do this with the midbass and tweeter too, but it might be harder to get a deep valley to form at 5khz. See my graph below for an example of what to look for. This graph and many more like it along with how it all works is documented in my build thread, also in my signature.


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## buckeyebeats

ok


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