# How to Tune a DSP



## spyders03

I got a new processor, so I decided to do some videos and hopefully help some people out that are first time DSP users, and maybe clear some things up on getting it set. Obviously there's a million and 3 ways to get to the end result, this is just what I have found to work for me. The last 2 videos are being uploaded right now, but the first 10 are up. 

If there's any other things you guys want me to cover, or would like to see, just let me know.




















































This is the first 10, the last 2 are being uploaded now, then I will likely do more about sound and acoustic theory if people are interested.


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## troutspinner

Nice job Spyders! There are not many videos around the net about tuning with REW and a DSP so this should help people get a much better understanding and to not be nervous about venturing into the world of DSP.

Like you said, there are a thousand ways of tuning but if I could offer a suggestion. A possibly faster and more precise method for PEQ'ing drivers may be achieved by using measuring sweeps and placement of the mic as outlined by Hanatsu in his thread http://www.diymobileaudio.com/forum/2097925-post16.html.

After you take your measurements and average them, you can then use REW's EQ feature to match to a target response. This will give precise values in both frequency and Q that you can enter into the DSP software without having to flip back and fourth and work certain frequencies with trial and error Q's. Your experience shines here but for someone new, sweeps and matching to target could provide better results.

Also, crossovers. Your experience shines here again but if you could throw up a video of overlapping SPL graphs of average responses of individual speakers, it would show the audible crossover and take some guess work out of people trying to figure out the best crossover points. There are a thousand posts on this forum about "Where should I set my crossovers" and I am sure I probably made a few of them!  but with using REW, it will tell you. There is finesse after that but it is the best starting point one could get.

Once again, nice job and thank you for taking the time to show this to people. Since I started using a DSP and REW and I cannot tell people enough to jump into this world, the results are worth it.


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## spyders03

troutspinner said:


> Nice job Spyders! There are not many videos around the net about tuning with REW and a DSP so this should help people get a much better understanding and to not be nervous about venturing into the world of DSP.
> 
> Like you said, there are a thousand ways of tuning but if I could offer a suggestion. A possibly faster and more precise method for PEQ'ing drivers may be achieved by using measuring sweeps and placement of the mic as outlined by Hanatsu in his thread http://www.diymobileaudio.com/forum/2097925-post16.html.
> 
> After you take your measurements and average them, you can then use REW's EQ feature to match to a target response. This will give precise values in both frequency and Q that you can enter into the DSP software without having to flip back and fourth and work certain frequencies with trial and error Q's. Your experience shines here but for someone new, sweeps and matching to target could provide better results.
> 
> Also, crossovers. Your experience shines here again but if you could throw up a video of overlapping SPL graphs of average responses of individual speakers, it would show the audible crossover and take some guess work out of people trying to figure out the best crossover points. There are a thousand posts on this forum about "Where should I set my crossovers" and I am sure I probably made a few of them!  but with using REW, it will tell you. There is finesse after that but it is the best starting point one could get.
> 
> Once again, nice job and thank you for taking the time to show this to people. Since I started using a DSP and REW and I cannot tell people enough to jump into this world, the results are worth it.


Thanks for the good advice, and I will likely do future videos on using sweeps, but figured this is an easier way to get started, since you can play pink noise off of a CD, and not have to worry about input and output and everything. And I talk some more about crossovers in the part 7 and 8, when we get into EQ'ing each driver. I will likely do more videos talking about such things, and actually have a game plan on actually showing the effects of such adjustments, and over-underlapping. Thanks again for the positive feedback, and I will try and work on your suggestions also.


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## SQLnovice

Vote to please sticky this.


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## Elgrosso

Very cool, thanks for your time!


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## brumledb

Have not watched yet but I definitely will be. Thanks for posting.


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## troutspinner

spyders03 said:


> figured this is an easier way to get started, since you can play pink noise off of a CD, and not have to worry about input and output and everything.


I sometimes forget how easy I have it. The HU in my truck has a 3.5mm jack so it's just a plug from there to the laptop. Had it been some other vehicles I've had, this makes sense.



spyders03 said:


> I talk some more about crossovers in the part 7 and 8, when we get into EQ'ing each driver. I will likely do more videos talking about such things, and actually have a game plan on actually showing the effects of such adjustments, and over-underlapping.


Nice! Can't wait to see that. I recently played with overlapping heavily with mixed results. I'd like to see someone else's approach and opinions.

Keep up the good work!


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## bigbubba

Great job on the videos Kyle. Had a question on video 5 on the Tracerite software. You mentioned if you are using a Pioneer HU, to select that option when calculating the TA. If you have a Pioneer HU but are doing the TA, xover and eq in the Helix does that still hold true?


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## spyders03

bigbubba said:


> Great job on the videos Kyle. Had a question on video 5 on the Tracerite software. You mentioned if you are using a Pioneer HU, to select that option when calculating the TA. If you have a Pioneer HU but are doing the TA, xover and eq in the Helix does that still hold true?


No, because you are using the helix for time alignment


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## Sonic525

This is awesome. Thank you so much spyders03. Need to set some time aside and watch all your vids. I have been looking for something like this for quite some time now.


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## lizardking

When using the RTA. What bit rate and sampling should be used? 16 bit, 24 bit, 48k or 44.1k sampling. I notice you have it setup as 16 bit @ 44.1k sampling.


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## #1BigMike

Fantastic. I agree this should be a sticky.


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## Robo99

Very handy, especially for new users. Thank you for the time vested and the way you try to make every person understand. This is a handy go-to for any standalone DSP, or HU with DSP user.


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## spyders03

Thanks for the great feedback guys. If there's anything you want me to do videos on in the future, please let me know.


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## markn01

Great info!


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## crackinhedz

Had a binge watching session this evening, great info! Definitely gave me some ideas to try.

Curious if you will upload the CD with 31 band pink noise you mentioned in the last vid. Would be great!


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## truckerfte

Subbed for future reference


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## vabch22

sub'd for my noob self. thanks so much for this!


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## sirbOOm

Well this is a sticky if I've ever seen one!


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## Huckleberry Sound

Information!!!


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## Babs

sirbOOm said:


> Well this is a sticky if I've ever seen one!


Agreed!



vabch22 said:


> sub'd for my noob self. thanks so much for this!





truckerfte said:


> Subbed for future reference





crackinhedz said:


> Had a binge watching session this evening, great info! Definitely gave me some ideas to try.
> 
> Curious if you will upload the CD with 31 band pink noise you mentioned in the last vid. Would be great!


Search for Kyle in here and you'll see how many times I refer folks to Kyle's vid series. It literally got me up and running actually putting the knowledge to use and learning so much more by actually DOING the tuning finally.. Putting the information gained from guys like Erin, Kyle, Chad, others to good use. 

The vids prove one thing to me. There's no substitute for actually seeing it being done. You can tell a guy all day long how to build a sub box, or smoke a rack of ribs, but a 10 minute video is absolute king of the hill.. Especially a whole series of them. 

A video is worth a thousand threads. 

.. In short. Thank you from this newb who knows enough to be dangerous but a helluva lot more after watching these vids (over... And over)!


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## Phil Indeblanc

I found your videos on Utube before this here. I think they are very informative, Thank you for sharing. I do have to do a lot of sifting and jumping around for a newb like me. I look forward to seeing a step by step of first things first, " ...After you have all your gear in....etc". Do this, then this, then this, and that. 

Something I can follow would be a blessing. None the less this is surely something to add in to other videos to get me started from top to bottom.
Some are doing it while in the car, others NOT in the car...etc.
Also, I have seen people take RTA readings with the zero axis head on narrow angle of the mic, and I seen your ear to ear 90 degree version, and then yet I have heard to take readings of the tweeters in dash from opposite sides of the car for better results. 

(left tweeter, right passenger window/right tweeter, driver window). etc...

Does it make a difference? Why?, and how? and is there a measurable better method?


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## SkizeR

kyle, wheres the video on how to tune a for a 2 seat car


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## Phil Indeblanc

Just take half of what he said into consideration for a 2 seater


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## SkizeR

Phil Indeblanc said:


> Just take half of what he said into consideration for a 2 seater


take half... ? i was a joke btw. tuning a 2 seat car is a nightmare


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## Babs

Phil Indeblanc said:


> I found your videos on Utube before this here. I think they are very informative, Thank you for sharing. I do have to do a lot of sifting and jumping around for a newb like me. I look forward to seeing a step by step of first things first, " ...After you have all your gear in....etc". Do this, then this, then this, and that.
> 
> Something I can follow would be a blessing. None the less this is surely something to add in to other videos to get me started from top to bottom.
> Some are doing it while in the car, others NOT in the car...etc.
> Also, I have seen people take RTA readings with the zero axis head on narrow angle of the mic, and I seen your ear to ear 90 degree version, and then yet I have heard to take readings of the tweeters in dash from opposite sides of the car for better results.
> 
> (left tweeter, right passenger window/right tweeter, driver window). etc...
> 
> Does it make a difference? Why?, and how? and is there a measurable better method?


I'll try to answer.. 

1) To apply it, watch them in series as they're numbered in order and perform them the same, from crossovers through levels and TA through into individual driver EQ etc etc. These methods are just the method Kyle shows and as he states, there are many methods and orders of events, none really wrong. It's what works for you. The measurements from the mic and your two organic mics (ears) will let you know.

2) There are a gazillion different methods from measuring outside the car with mic in the headrest, etc etc.. 90 off-axis or point on-axis with the mic. Erin has a vid showing this as a demonstration on taking RTA noise measurements outside the car. Don't sweat the small stuff. If using 90 degrees, try to have a mic with 90 degree calibration file loaded in REW. Measuring inside the car is just easier and takes into account your actual person as part of the "room" which will have an acoustic affect on response.

3) This method is also for a single seat tune, thus he is measuring the averages around one noggin, driver seat. So the mic moving during the averages are done around that noggin. So as thus, it'd make no sense for measurements with mic in any other spots.. be it left or right tweet, mid etc. Measure at your head if tuning to sound perfect at your head. 

... In fact, I'd bet, for two-seat tune, if I had to guess, you'd take your measurements head height right between the two head positions for an equal average tune at both head locations. There might be other factors there uniquely measured at each head location, but that might be one method for 2-seat tune.


By the way.. A while back I put all these in a playlist for my own benefit and quick referal. I just found out you can manually order them so I put them in order from top/down 1-12. Starting at the top.. And a 1.. and a 2.. 

https://www.youtube.com/playlist?list=PL8DsRfMp9q4az_gei9C27aRyUIUvMIMO0


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## Phil Indeblanc

do you think I was serious ? 

Thanks so much for that Babs....I'll work through them next tune sitting.

Maybe the answer is to have Tune parties. That way we have an exuse to put all this time in. And with drinks all things start to sound better.


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## sunshinefc3s

EXCELENT! Thank you.


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## SkizeR

Phil Indeblanc said:


> do you think I was serious ?
> 
> Thanks so much for that Babs....I'll work through them next tune sitting.
> 
> Maybe the answer is to have Tune parties. That way we have an exuse to put all this time in. And with drinks all things start to sound better.


cant really tell on the internet lol


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## Phil Indeblanc

look for the light humor, not the dark truth.


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## Babs

Phil Indeblanc said:


> do you think I was serious ?


Ah ya never know around these parts. 



Phil Indeblanc said:


> Maybe the answer is to have Tune parties. That way we have an exuse to put all this time in. And with drinks all things start to sound better.


Always works for me.. Then I get in the car the next day and I'm like WTF!!


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## lizardking

A 90 degree calibration file......LOL


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## crackinhedz

question, if anyone can answer...

In the video when RTA'ing the individual driver, he made note that the driver was still producing harmonics outside of the crossover slope...for instance, the midbass was lowpass crossed at 300HZ @ 24db LR (if I recall correctly) but during measurement he was still picking up random sound in the 1khz-2khz range...

Observing his EQ graph, everything outside the crossover slope was left at 0 db. 

Would it not benefit to drop the frequencies outside the crossover ranges to lowest possible level, -12db or whatever your DSP allows? This way those frequencies have less chance to even come into play?

Or is a harmonic just unavoidable sometimes?


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## Phil Indeblanc

He may have meant to say the top end freq of the mid bass is 300 and lower. Likely his mid picks up from 300 to 2000 or so. Just guessing verbiage, I forgot if he had a 3way or not ?


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## crackinhedz

Phil Indeblanc said:


> He may have meant to say the top end freq of the mid bass is 300 and lower. Likely his mid picks up from 300 to 2000 or so. Just guessing verbiage, I forgot if he had a 3way or not ?


correct, but hes measuring the driver by itself. He indicates that the crossover shows rolloff but a ways higher up in freq there is still some residual response.

I will have to go back a check out the spot im referring to.


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## SkizeR

thats how crossovers and their slopes work. crossovers arent a dead stop. theyre a gradual roll off. and no it wouldnt benefit by cutting the eq after the crossover. you would just use a steeper slope. but, various slopes are used to help the drivers blend into each other


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## Phil Indeblanc

Yes, from what I can see happening I would agree with the cat above. 

The freq tapers after the point and the dB's help dictate how sharply. Q I have yet to figure out how and when to use, but I think I read someone say it is more for sub/bass. So if you need freq cut, maybe start much sooner or later, but that would be very experimental as this is just to see if it stops, not if it sounds good


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## crackinhedz

Ok went back and rewatched Vid 8 about 10 minute mark...left midbass

He ends up dropping the crossover to like 150hz, but stil has flat response to like 300-400 then rolls off and the a slight bump at 550hz.

Mentions cabin gain affecting this region, so I guess I can see why the crossover isnt the end all be all like Skizer mentioned (and of course I know frequency doesnt fall off a cliff, rather rolls off depending on the crossover type).

I was simply wondering if lowering the EQ band outside the crossover range would effectively aid the crossover in any way. I mean, could it not hurt to set a midbass 2khz to -12db than to keep at 0 db? I know the crossover should never let the midbass w/ 200hz crossover really even see 2khz signal, but would it hurt to do it this way in conjunction with a crossover? 

Or is it just pointless and so I should forget such a wacky idea? Just trying to learn.


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## SkizeR

crackinhedz said:


> Ok went back and rewatched Vid 8 about 10 minute mark...left midbass
> 
> He ends up dropping the crossover to like 150hz, but stil has flat response to like 300-400 then rolls off and the a slight bump at 550hz.
> 
> Mentions cabin gain affecting this region, so I guess I can see why the crossover isnt the end all be all like Skizer mentioned (and of course I know frequency doesnt fall off a cliff, rather rolls off depending on the crossover type).
> 
> I was simply wondering if lowering the EQ outside the crossover range would effectively aid the crossover in any way. I mean, could it not hurt to set a midbass 2khz to -12db than to keep at 0 db? I know the crossover should never let the midbass really even see 2khz signal, but would it hurt to do it this way in conjunction with a crossover?
> 
> Or is it just pointless and so I should forget such a wacky idea? Just trying to learn.


pointless. you would just use a steeper slope


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## crackinhedz

SkizeR said:


> pointless. you would just use a steeper slope


I guess I just didnt see him change his slope (or maybe he tried), just lowered the crossover freq. But cabin rise was fighting against him.

Oh well, not curious anymore. Thanks SkizR.


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## SkizeR

crackinhedz said:


> I guess I just didnt see him change his slope (or maybe he tried), just lowered the crossover freq. But cabin rise was fighting against him.
> 
> Oh well, not curious anymore. Thanks SkizR.


no problem. i wouldnt bother with eq to far after the crossover unless the was an abnormal peak


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## Phil Indeblanc

lizardking said:


> A 90 degree calibration file......LOL


I'm pretty sure that's what cross spectrum sent me in the 3 cal files.


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## SkizeR

Phil Indeblanc said:


> I'm pretty sure that's what cross spectrum sent me in the 3 cal files.


What Mic is it? Usually measurement mics are omnidirectional. One file is probably flat, one a-weighted, and one c-weighted

Sent from my HTC6525LVW using Tapatalk


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## Phil Indeblanc

It's the UMM6 USB. I got it from cross spectrum. They sent 3 cal files with it on a USB stick.


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## subterFUSE

SkizeR said:


> What Mic is it? Usually measurement mics are omnidirectional. One file is probably flat, one a-weighted, and one c-weighted
> 
> Sent from my HTC6525LVW using Tapatalk



Cross Spectrum Labs sends On Axis, 45 degree and 90 degree off axis cal files. I have the same UMM6 and that's what they sent me.

High freq sounds tend to roll off when measuring off axis. The off axis cal file compensate for that.


Sent from my iPhone using Tapatalk


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## crackinhedz

On/Off axis in regards to how you hold thd mic, or how the speaker is aiming?

I have a Dayton UMM, but not from Cross Spectrum so only the one cal file. Should I be pointing the tip of the mic in direction of the soundstage vs. Pointed up at the roof?


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## subterFUSE

crackinhedz said:


> On/Off axis in regards to how you hold thd mic, or how the speaker is aiming?
> 
> I have a Dayton UMM, but not from Cross Spectrum so only the one cal file. Should I be pointing the tip of the mic in direction of the soundstage vs. Pointed up at the roof?


The mic cal files are based on where the mic is aiming.


0 degree on-axis means the mic is pointed directly at the sound source.

45 degree means mic pointed 45 degrees off-axis.

90 degrees would be pointed perpendicular to the sound source.


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## SkizeR

subterFUSE said:


> Cross Spectrum Labs sends On Axis, 45 degree and 90 degree off axis cal files. I have the same UMM6 and that's what they sent me.
> 
> High freq sounds tend to roll off when measuring off axis. The off axis cal file compensate for that.
> 
> 
> Sent from my iPhone using Tapatalk


interesting. i always thought that it was omnidirectional


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## subterFUSE

SkizeR said:


> interesting. i always thought that it was omnidirectional


Depends on frequency.

Most mics will have a high frequency rolloff based on directivity. That's why we get them calibrated. 


Very similar to how all speakers eventually beam, depending on frequency.


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## Babs

Yep. My UMM-6 came with 0, 45 and 90 cal files for "narrow band" and "1/3 octave" each. Taking a guess, using REW, I have 90 narrow band loaded as the cal file for tuning as Kyle demonstrated in the vids. 


Sent from iPhone using Tapatalk


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## Phil Indeblanc

And I used the 0 narrow so far for on axis like a few I have seen placing the mic around the headrest. 

While sitting in the car (as I am a larger mass than other things in the car and I think I might make a sonic difference), I hold the mic at my mouth position, then left outer shoulder and then right.

But an Audio Pro told me to calibrate the dash drivers, tweeters in my situation (you might have mids in the dash).... from opposite sides of the driver I'm working on to get a better reading.

I think holding the mic, let alone moving it may introduce vibes and noise and kinda add things that I likely can ignore, but rather not include in the reading.


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## lizardking

I use the UMIK-1 and held it 90, 45 and 0 degrees. Measures the same. However, it does come with a 90 degree file to use with the NanoAVR.


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## CoLd_FuSiOn

crackinhedz said:


> On/Off axis in regards to how you hold thd mic, or how the speaker is aiming?
> 
> I have a Dayton UMM, but not from Cross Spectrum so only the one cal file. Should I be pointing the tip of the mic in direction of the soundstage vs. Pointed up at the roof?


http://www.diymobileaudio.com/forum...first-timers-guide-measuring-your-system.html

You can see how you're supposed to position the mic,it's usually facing the windscreen.That's the exact reason why you got the 45 and 90 degree calibration file as microphones get directional in the higher frequencies.They are to compensate for that as in the car you're not measuring on axis.


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## rayray881

Old post! I have a tuning question. After having everything time aligned, levels matched, and each side (l&r) eq’d to within 1 dB across the range, what do you do if the center image still pulls one way? 
Adjust levels of independent drivers? Bandpass pink noise and further eq? I’ve read not to mess with time alignment once set. Any suggestions, thanks.


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## Jscoyne2

rayray881 said:


> Old post! I have a tuning question. After having everything time aligned, levels matched, and each side (l&r) eq’d to within 1 dB across the range, what do you do if the center image still pulls one way?
> Adjust levels of independent drivers? Bandpass pink noise and further eq? I’ve read not to mess with time alignment once set. Any suggestions, thanks.


Tune by what sounds best. Period.

Isolate a set of drivers. So both midbass. Or both midrange. Or both tweeters.

If those drivers are playing 2k and down. Focus on moving image with time alignment and a little bit of level changing 

If 2k and up. Its pretty level dependent.

Sent from my XT1710-02 using Tapatalk


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## SkizeR

Jscoyne2 said:


> Tune by what sounds best. Period.
> 
> Isolate a set of drivers. So both midbass. Or both midrange. Or both tweeters.
> 
> If those drivers are playing 2k and down. Focus on moving image with time alignment and a little bit of level changing
> 
> If 2k and up. Its pretty level dependent.
> 
> Sent from my XT1710-02 using Tapatalk


This is pissing in the wind. If delays are set properly and your center image is still off, you should be using measurement and verify with ears to see if pairs of drivers are equal volume from side to side. More times than not, they may measure similar, but one side will be a bit louder when verified by ear. Use levels to adjust. Otherwise, you are just introducing comb filtering. If levels sound and measure right, you might want to revisit how you are setting delays, whether it means being more precise with the tape measure, or by using a tape measure from the get go instead of trying some random method you read on this site. 

Just curious rayray, where does your center sound like it's coming from? In front of you? Center of the dash? 

Sent from my SM-G975U using Tapatalk


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## EmoJackson

SkizeR said:


> This is pissing in the wind. If delays are set properly and your center image is still off, you should be using measurement and verify with ears to see if pairs of drivers are equal volume from side to side. More times than not, they may measure similar, but one side will be a bit louder when verified by ear. Use levels to adjust. Otherwise, you are just introducing comb filtering. If levels sound and measure right, you might want to revisit how you are setting delays, whether it means being more precise with the tape measure, or by using a tape measure from the get go instead of trying some random method you read on this site.
> 
> Just curious rayray, where does your center sound like it's coming from? In front of you? Center of the dash?
> 
> Sent from my SM-G975U using Tapatalk



I've tried several tuning methods and what I found that works best for me is:

1. Set T/A By Tape Measure.
2. Level Match all Left Side to Target Curve as Close as Possible. 
3. EQ Left Side to match Target Curve.
4. Make the Left Side my new target curve and match the right to left. 

Even then I find that I have to adjust the volume level of the left side slightly. Otherwise the vocals have an image directly in front of me, and not at the center of the dash.


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## rayray881

Skizer, I set ta by using a tape measure. Center image is a few inches to the left. This is a 3 way front stage. Midbass is crossed 80-200hz, midrange is 200-4khz, tweets 4-20khz. Sounds like a phase issue below 200hz, as I can add additional delay to the left midbass and image doesn’t move much to the right regardless. They are correct as far as polarity.


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