# Nulling is the best for time alignment



## drop1 (Jul 26, 2015)

Nulling is the absolute best way to set ta due to peoples head shape, position and hearing.

Convince me otherwise.

For subs, midbass and midrange drivers, nulling is more accurate than any method I've ever tried and I've used them all through the years.


Impulse response, smaart, tape measure and some other oddities.

I believe this is because of having 2 ears vs a single mic point.

I'll give an example. Using a tape measure to get close then using REW for impulse response 
I an able to get a really solid center image. It has to me moved a bit using levels but solid.

I knew I need some fine tuning in the vocal range. They sounding like I had a bit too much 1khz and I knew I didnt. The vocal was also sitting just a touch low which could be eq.

I've spent 2 says trying to get the vocal smooth now. 
What worked is nulling the mid drivers.
It was about 1 inch off the impulse response. The nulling brought that to my attention and after correction, the vocal moved slightly left. A touch of channel reduction on the drivers side lead to what I was seeking. Vocals are now correct. Smooth, they sit high and have great 3 dimensionality. They weren't horrible before just a tiny bit rough and a bit flat sounding.
After adjusting these my subs needed to be moved backwards in time about 2 inches to lock back in.

I like the fancy programs but man doing it by ear under the right circumstances is so much more accurate. 

We haven't had a tutorial on nulling here in a while. If anyone is interested I'd be glad to write one up. Its extremely simple and uses pink noise or test tones depending on what type of drivers you are running. 

If you've set your ta using only impulse response or a tape measure this would really be worth a shot. The increase in intelligibility is where it's at. 

If you decide to go forward I suggest saving the current tune so you can a/b with the new corrected tune. I guarantee you'll have better results than if you are using a mic.

It's only downfall is it's very hard to hear on tweeters that dont play super low.


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## Mahapederdon (Aug 19, 2016)

I'd be very interested to try your way if you do a small tutorial.


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## Truthunter (Jun 15, 2015)

So you talking flip polarity on a driver pair and play tones at the crossover - adjust delay till the least output is heard and them flip back polarity?


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## bharatsoneji (Jan 24, 2019)

Looking forward to a mini ‘how to’

Thanks


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## Holmz (Jul 12, 2017)

drop1 said:


> Nulling is the absolute best way to set ta due to peoples head shape, position and hearing.
> 
> Convince me otherwise.
> ...


Very clever.




drop1 said:


> ...
> I believe this is because of having 2 ears vs a single mic point.
> ...


^No, unit-ah^... I doubt ^it^...

Take a sine wave... how do you find the peak? The derivative is zero and one has to move a lot of degrees away in phase before they notice it is quieter.

Now sum those two signal with one out of phase.
This produces a V shaped null when they are perfectly aligned... and one only needs to move a tiny amount and thy are up the side of the V.

In math terms the null has a steeper gradient, than a sum beam peak... with the later having the gradient be exactly zero.


What you came up with is really pretty clever, and makes sense when when it is considered mathematically.
(Well done, you !)


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## drop1 (Jul 26, 2015)

Holmz said:


> drop1 said:
> 
> 
> > Nulling is the absolute best way to set ta due to peoples head shape, position and hearing.
> ...


You are smarter than me so I can't argue with you. I only have real world experience.


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## drop1 (Jul 26, 2015)

Truthunter said:


> So you talking flip polarity on a driver pair and play tones at the crossover - adjust delay till the least output is heard and them flip back polarity?


For small drivers I use pink noise. It's easier hear. For subs I use a tone in the crossover region.


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## Holmz (Jul 12, 2017)

drop1 said:


> You are smarter than me so I can't argue with you. I only have real world experience.


^Bull$hit^...

Knowing the math is good, but the insight to try the nulling (either by chance or intent) is somewhat more important.
(It is so obvious with the math, it is embarrassing... I am bit envious I did nit think of it.)

You may not know it, but (IMO) You've done some brilliant work.
And creativity is a pretty important component to breakthroughs.

Lastly; Math is not in a separate world from the real world... it describes the real-world...


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## jtrosky (Jul 19, 2019)

I'm not sure I understand "how" to do this yet, but I'd love to try it. Hopefully, you can find the time to put together that tutorial that you mentioned - would be much appreciated! 

Thanks!


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## Jcmamma (Apr 5, 2017)

I also would live to read a “how to” on nulling. Always willing to tinker for better results on the system.


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## drop1 (Jul 26, 2015)

It's really easy. I'll type up a step by step today.


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## Mahapederdon (Aug 19, 2016)

drop1 said:


> It's really easy. I'll type up a step by step today.


I always love the tutorial threads. Your the man. Or in these days should I say your the insert identity "here"


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## dumdum (Feb 27, 2007)

Holmz said:


> ^Bull$hit^...
> 
> Knowing the math is good, but the insight to try the nulling (either by chance or intent) is somewhat more important.
> (It is so obvious with the math, it is embarrassing... I am bit envious I did nit think of it.)
> ...


If you’d care to speak English instead of inserting stuff in <brackets> then it would make a lot more sense as I don’t know if you’re trying to slag him off or compliment him! You sound like your using google translate from Russians or something... just saying ??


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## Holmz (Jul 12, 2017)

dumdum said:


> If you’d care to speak English instead of inserting stuff in <brackets> then it would make a lot more sense as I don’t know if you’re trying to slag him off or compliment him! You sound like your using google translate from Russians or something... just saying ??


The parenends are to signify a separate thought, and sometimes and internal thought.

It is pretty brilliant work... (I think said it a few times.)

Not slagging... except maybe that the "real world" part seemed to be a poke at math and science are some separate world... which they are not. (Math is the language of physics.)

I cannot wait to see the tutorial, but at this point it seems kind of obvious as to what one should do... (basically i think that one should invert one side and adjust delays to minimise the volume, I think??... but that usually makes a diffuse sound.)


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## Stycker (Jan 31, 2018)

I would love to try this as well. I currently use tape measure and then set levels by ear to center the image. This works fairly well, but sometimes with this method I get image left of center with too much power on the right side if that makes any sense.


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## drop1 (Jul 26, 2015)

I'll try my best to explain the process. I didn't invent this, it's used quite a bit on pro audio and has been mentioned here as well. I simply refined it in a way that works for me.

Ideally you will have some driver eqing already done . It's much easier to hear differences with decent eq, crossovers and channel gains in place.

Start out with a tape measure and enter the distances for each speaker. This step will get you close quickly.

After that is done verify polarity one last time. If you have a solid center image already, polarity it likely good. 
Do not try to adjust anything at this stage to further center the image. It is counter productive. Just enter the approximate distances measured with a tape measure. 

Next you'll want to mute all drivers except the mid bass/mids. 

Play mono (correlated) pink noise.
Flip the phase on the drivers side speaker. 
Keeping your head where it would normally be, move the delay on the reversed polarity driver up and down. You will hear the sound pull right or left as you go too far in either direction.

You'll need to go back and forth a little too far in each direction until you get the hang of what you are hearing. You are listening for the weakest point. It sounds weird. The correct spot is as out of phase as it gets so it almost feels like your ears are in a vacuum.

Once you are satisfied that you've reached the absolute middle and are hearing the drivers 180 degrees out of phase, return the drivers side mid to correct poliatiry. 

Do NOT move it again. This is you're time alignment fir these drivers no matter where the image is. We will address moving the image later. 

Repeat this process for every pair of drivers. Forget about subs for now.

Once every pair of drivers is done, we move on to matching non like drivers. Think midbass to mids or mids to tweeters. 

For dissimilar drivers I prefer to use test tones. You'll want a tone smack dab in the middle of the crossover region so that both drivers can play it equally. You can try pink noise too. Sometimes it can be a bit more revealing than tones.

Next we will need to align dissimilar drivers to each other. 

The time difference between the left and right drivers you've matched should never change. 

If you have the ability to lock 2 channels together as pairs, lock each pair of like drivers together after aligning them. This way you can add or reduce delay as needed without damaging the fine aligmnet you've already dialed in on each pair. 

You will now reverse polarity on the pair of drivers you are trying to align. Midbass to mids for explample. Youd flip the polarity of the mids and move them togthers listening for the sound to be its weakest or as close to 180 degrees out of phase as possible. When satisfied return the phase to normal.

Do this for every pair of drivers. Midbass, mids , tweeters. (Tweeters are a pain in the ass. It's very hard to hear phase with them. Take your time and do the best you can. Tweeter volume plays a much larger role in getting a solid center.)


Now that we have dialed in our ta as best we can, mute every pair of drivers but the mids or midbass. 

Play a vocal that is known to have a solid center.
Use channel VOLUME to to move your center image left or right to your taste. 
When you are satisfied with those drivers center, mark ir with a piece of tape on the dash or windshield.

Repeat those process for every set of drivers, pair by pair using ONLY CHANNEL VOLUME to align each pairs center to the piece of tape or marker you've used to mark center. 
Do NOT touch the ta again . If you are confident that you have done the ta correctly as you went you will never have to touch the time alignment again. Everything else is eq and volume. 


Now subs. Subs benefit the most from this. This process with put your subs in front of you.

Using 24dblr crossover slopes on the subs and midbass will give the easiest results. Using odd crossover slopes needs further phase correction.

Using a test tone in the crossover region say 80hz, turn your head side ways. 
Turn the sub up or down in volume until the sub and midbass sound very close in volume. 
Flip the polarity a few times on the subs until you are sure you are hearing them out of phase with the midbass. 
It should sound completely disconnected from each other. 
While playing the test tone, move the ta for the subs up and down and you will hear the subs move front to back. We are looking for that perfect balance of being 100 percent out of phase. It will feel like the air is being sucked out of your ears. 

Once you find the least loudest most out of phase spot, flip the polarity on your subs back to normal and your bass will jump to the dash. 

That's it. On a side note, while doing subs, turn off any subsonic or high pass filters. They created small phase shifts that should be corrected with fine phase adjustment not time alignment. 

And remember, do not go tinkering with the ta again unless you dont think you got it right. It's kind of hard to mess this up.

Your mids may wind up imaging directly in front of you and your midbass or tweeters may imagine further right. This is normal and needs to be addressed with eq and volume to get perfectly centered. 

I'm sure this isn't perfect science but its lightyears sharper and more focused than any other method I've ever used. 


This is my method. If anyone sees potential flaws or wants to add anything, please do so. 
I typed this from a phone and it was rather hard to keep up.


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## drop1 (Jul 26, 2015)

Stycker said:


> I would love to try this as well. I currently use tape measure and then set levels by ear to center the image. This works fairly well, but sometimes with this method I get image left of center with too much power on the right side if that makes any sense.



I want you to try this test.

Play some good music. Close your eyes. 

Use your hand to find where the sound from the drivers side stops. Try to touch the edge of the sound. 

When I do this, my hand hits the side window of my truck. I have to roll the window down to find the edge of the sound which is about 6 inches outside the truck. The sound extends past the glass. 
We get caught up in wanting the center to be directly in the middle of the dash but the center should be directly in the middle of the sound. 
Sometimes that means not being in the center of the dash but a little closer to your side of the car. 

That simple test will show you where you should center.


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## dcfis (Sep 9, 2016)

Where in LA are you?


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## drop1 (Jul 26, 2015)

dcfis said:


> Where in LA are you?


Baton rouge. Are you close? I'd love a new stereo buddy!


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## DaveG (Jul 24, 2019)

drop1 said:


> dcfis said:
> 
> 
> > Where in LA are you?
> ...


Metairie here! Is this a hobby or are you in the business?


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## drop1 (Jul 26, 2015)

DaveG said:


> drop1 said:
> 
> 
> > dcfis said:
> ...


100 percent hobby. You're not even an hour away.


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## DaveG (Jul 24, 2019)

drop1 said:


> DaveG said:
> 
> 
> > drop1 said:
> ...


I know Baton Rouge well... in fact my son just graduated from LSU this past May. I’ll pm you later so we don’t clutter up this thread.


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## saltyone (Feb 2, 2019)

DaveG said:


> drop1 said:
> 
> 
> > DaveG said:
> ...


Geaux Tigers! West Monroe here. I’ll be at the show in Gonzales on 09/21 and state finals in Gonzales on 09/28. It would be great to meet some DIYA folks!


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## Locomotive Tech (May 23, 2016)

Subb'd


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## drop1 (Jul 26, 2015)

saltyone said:


> DaveG said:
> 
> 
> > drop1 said:
> ...


Where in Gonzales ? Ralphs?


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## jtrosky (Jul 19, 2019)

Thanks for the write-up. Definitely sounds a little more complicated than I was expecting/hoping.  Think I'll just stick with the measured way of time alignment for now - however, eventually, I'll give this method a shot. 

If anyone else gives this a shot - please do report back.


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## Lou Frasier2 (Jul 17, 2012)

Mahapederdon said:


> I always love the tutorial threads. Your the man. Or in these days should I say your the insert identity "here"


only in Berkeley is this not allowed, so say it all you want


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## TitanCCBT3 (Jul 15, 2012)

Here in Kenner Brah!


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## drop1 (Jul 26, 2015)

jtrosky said:


> Thanks for the write-up. Definitely sounds a little more complicated than I was expecting/hoping. ? Think I'll just stick with the measured way of time alignment for now - however, eventually, I'll give this method a shot.
> 
> If anyone else gives this a shot - please do report back.


It's not complicated. If you already have a base tune its stupid easy. In fact the closer your system is to tuned, the better. This is FINE time adjustment.

Mute everything expect your midbass. Flip the polarity on one. Make tiny adjustments up and down on the ta until the sound is the quietest, flip polarity back.

Then play both midbass and the sub. Flip the polarity on the sub and repeat the process making the sound as quite as you can and flip the polarity back.

If nothing else, do the sub. If that doesnt make you want to continue, stop there. At least you'll have great upfront bass if nothing else.

I can do this in like 3 minutes. It sounds complicated but once you hear it you will instantly understand.


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## tjk_bail (Feb 2, 2012)

drop1 said:


> We get caught up in wanting the center to be directly in the middle of the dash but the center should be directly in the middle of the sound.


^^ THIS ^^ ... I totally agree the 'center should be directly in the middle of the sound'... I haven't realize it until I read your statement, but it makes really good sense to me.

I'm going to give your method a try in the next few days....

Thank you for the Write-Up !!


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## SkizeR (Apr 19, 2011)

If your car is set up right, those two should be the same spot

Sent from my SM-G975U using Tapatalk


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## DaveG (Jul 24, 2019)

TitanCCBT3 said:


> Here in Kenner Brah!


Here ya go:


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## drop1 (Jul 26, 2015)

SkizeR said:


> If your car is set up right, those two should be the same spot
> 
> Sent from my SM-G975U using Tapatalk


Eh, sorta. It depends on the car. The right side of my stage ends at the passenger door but the drivers side the edge of the stage is outside the window a bit. I center my stage directly in the middle based off edge to edge boundaries of the sound, not the physical limitations of the dash. That usually puts center somewhere between directly infront of me and center dash to get even side width on both sides.


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## Holmz (Jul 12, 2017)

SkizeR said:


> If your car is set up right, those two should be the same spot


Someone showed a process with a sub and screenshots from maybe a Helix??
They adjusted the phase in a similar fashion.

One could argue that this is somewhat like a phase adjustment.

Ideally one would set the TA, and then adjust the phase... but it does make sense doing it this way when there is no phase adjustment.
(But both sides should be at the same phase, so it should just be the same as the TA)


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## drop1 (Jul 26, 2015)

Holmz said:


> SkizeR said:
> 
> 
> > If your car is set up right, those two should be the same spot
> ...


That works too. Enter your distances into ta and use nulling to adjust fine phase then channel volumes to line up everything in the middle.


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## tyroneshoes (Mar 21, 2006)

looking forward to trying this. Thanks!


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## JMikeK (Jan 2, 2019)

Worked great on my sub and only took about 5 minutes with a youtube test tone. Lots of authoritative upfront bass and seamless midbass transition (using Pioneer's lovely 36 db/octave LP @ 80 Hz). Mostly the bass just sounds like music instead of something coming from the back of a car. No way I would have arrived at the setting I got without this method. Thanks! Plan to do the main drivers too soon, but that is a little more involved obviously.


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## eststang (Nov 28, 2010)

Tried it too and got slightly better image but specially sub blending is now much better and bass sounds so much smoother.


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## jdunk54nl (Apr 25, 2015)

Why does it have to be so hot in Phoenix...I really want to try this but when it is 110+ I am not willing to sweat that much....


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## jtrosky (Jul 19, 2019)

Wonder if this woud even do anything for me regarding the sub since my sub actually *is* "up front" anyway (under the seat sub).  Can't hurt to try, I guess.


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## jdunk54nl (Apr 25, 2015)

jtrosky said:


> Wonder if this woud even do anything for me regarding the sub since my sub actually *is* "up front" anyway (under the seat sub).  Can't hurt to try, I guess.


This sounds like it is all about getting things to blend nicely. Even if you have a sub up front, that doesn't guarantee it blends nicely, it just makes it easy. 

So I would say this could definitely help.


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> jtrosky said:
> 
> 
> > Wonder if this woud even do anything for me regarding the sub since my sub actually *is* "up front" anyway (under the seat sub). ? Can't hurt to try, I guess.
> ...


Correct. Does not matter where the speakers are. This basically uses time alignment to align phase too.


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> Why does it have to be so hot in Phoenix...I really want to try this but when it is 110+ I am not willing to sweat that much....


This isnt one of those things you need to do with the car off. Crank the ac. Makes NO difference. Just turn it up enough to hear over the ac.


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## drop1 (Jul 26, 2015)

For those of you that have done your sub. Revisit your crossover point. Just move it up and down while listening to music. Watch that sub completely vanish into the windshield...


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## DavidRam (Nov 2, 2014)

I want to try this with my subs... What is the process with a Helix?


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## DavidRam (Nov 2, 2014)

drop1 said:


> I'll try my best to explain the process. I didn't invent this, it's used quite a bit on pro audio and has been mentioned here as well. I simply refined it in a way that works for me.
> 
> Ideally you will have some driver eqing already done . It's much easier to hear differences with decent eq, crossovers and channel gains in place.
> 
> ...


Oops I missed this post... Thanks


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## Holmz (Jul 12, 2017)

drop1 said:


> This isnt one of those things you need to do with the car off. Crank the ac. Makes NO difference. Just turn it up enough to hear over the ac.


Or take it that shop near Tempe called "Sonic Sauna".


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## Holmz (Jul 12, 2017)

DavidRam said:


> I want to try this with my subs... What is the process with a Helix?


It was literally two weeks ago a guy posted a video link.
1) Set TA.
2) twiddle phase to get the sub to the dash.

Under this process I think one wants to:
1)set the frequency be in the middle of the cross over region where the sub and mid bass have equal power... say 75 Hz.
2) Then flip the polarity of one.
3) Adjust phase to get the quiet null.
4) end adjust and set the phase back where it was.

That is how I would sum up the nulling


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## GMCtrk (Apr 14, 2018)

JMikeK said:


> Worked great on my sub and only took about 5 minutes with a youtube test tone. Lots of authoritative upfront bass and seamless midbass transition (using Pioneer's lovely 36 db/octave LP @ 80 Hz). Mostly the bass just sounds like music instead of something coming from the back of a car. No way I would have arrived at the setting I got without this method. Thanks! Plan to do the main drivers too soon, but that is a little more involved obviously.


Would you mind posting the step by step method. Ive read the OPs post a couple times and still can't figure it out clearly in my head. Thanks!


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## drop1 (Jul 26, 2015)

GMCtrk said:


> JMikeK said:
> 
> 
> > Worked great on my sub and only took about 5 minutes with a youtube test tone. Lots of authoritative upfront bass and seamless midbass transition (using Pioneer's lovely 36 db/octave LP @ 80 Hz). Mostly the bass just sounds like music instead of something coming from the back of a car. No way I would have arrived at the setting I got without this method. Thanks! Plan to do the main drivers too soon, but that is a little more involved obviously.
> ...


For sub, find a test tone in the crossover region. A tone beneath the mids high pass and subs low pass.

Play that tone amd turn your head side ways.

Raise or lower the subs volume until it sounds the same volume as the mids.

Flip the politely a couple times on the subs until you are sure the subs are out of phase with the mids.

You want to hear the subs and mids seprate. Mids in one ear, subs in the other.

Then on the time aligmnet slowly move the subs ta back and forth and listen to how the bass shifts back and forth. You want to make the interaction between the subs and mids as bad as possible. Subs should sound like they are 100 percent in the back of the car and mids 100 percent in the front. 

When you reach this stage flip the polarity on the subs 1 time and you are done.


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## Holmz (Jul 12, 2017)

drop1 said:


> For sub, find a test tone in the crossover region. A tone beneath the mids high pass and subs low pass.
> 
> Play that tone and turn your head side ways.
> 
> ...


I think that one should also be able to use an SPL meter and adjust TA for the minimum sound???

Basically with the meter where the head should be.


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## drop1 (Jul 26, 2015)

Holmz said:


> drop1 said:
> 
> 
> > For sub, find a test tone in the crossover region. A tone beneath the mids high pass and subs low pass.
> ...


Maybe but there is a small window. There isnt 1 perfect click depending on the resolution. On the helix the window is about 12 clicks wide. I shoot for the center of that window. 

With subs to midbass the windiw is much smaller but midbass to midbass has a pretty big window.


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## CDT FAN (Jul 25, 2012)

drop1 said:


> For sub, find a test tone in the crossover region. A tone beneath the mids high pass and subs low pass.
> 
> Play that tone amd turn your head side ways.
> 
> ...


What are you using to flip the polarity and adjust the alignment?


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## eststang (Nov 28, 2010)

Actually I used phase adjustment (in my Helix) for subs, because TA clicks are very small increments in bass region (very long wavelenghts!). It was very easy to spot the worst (quietest) spot with 80Hz sine. 

With midbass to mids I used TA adjustment with pink noise and juggling with the clicks back and forth, not so easy to get to the (un)sweet spot there but I think I got it, I went for the point where focus was the widest or blurriest. I did not even try to do tweeters, these are very close to the mids and I just adjusted their distance to be close to the mids.


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## drop1 (Jul 26, 2015)

eststang said:


> Actually I used phase adjustment (in my Helix) for subs, because TA clicks are very small increments in bass region (very long wavelenghts!). It was very easy to spot the worst (quietest) spot with 80Hz sine.
> 
> With midbass to mids I used TA adjustment with pink noise and juggling with the clicks back and forth, not so easy to get to the (un)sweet spot there but I think I got it, I went for the point where focus was the widest or blurriest. I did not even try to do tweeters, these are very close to the mids and I just adjusted their distance to be close to the mids.


If you use ta and phase together the bass arrives on time and is in phase though phase is definently the main thing you want with subs. 

How long the waves are has nothing to do with anything. That's some kind of odd science.

When music is made all the corrections to frequncy and arrival times are built into the process. Setting the subs slow to let the bass developed is nonsense.


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## jdunk54nl (Apr 25, 2015)

drop1 said:


> This isnt one of those things you need to do with the car off. Crank the ac. Makes NO difference. Just turn it up enough to hear over the ac.


Ya, but I need to dig deeper into my tune. I just did one quick pass after getting everything installed this summer and haven't had a chance (nor really want to in this heat) to go fix the issues that I can clearly hear.


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> drop1 said:
> 
> 
> > This isnt one of those things you need to do with the car off. Crank the ac. Makes NO difference. Just turn it up enough to hear over the ac.
> ...


I understand. I'm just not one that tunes with the car off. I understand the merits but having measured the difference with the car on and off it makes no difference in my measurements.
I drive a lot so I male tuning decisions while I'm driving. I make mental notes and apply them later. 
My system isnt built for sitting in the drive way type listening. My tune is setup to sound it's best while I'm on the road. It's a little bass heavy and little bright but sounds perfect at 60 mph.


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## jtrosky (Jul 19, 2019)

I've been noticing that when my tune sounds awsome sitting in the car without it running, it's not so great while driving down the road... While driving, I seem to have less bass... It's almost like you have to purposely "overdo" the bass a little to compensate for this...


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## drop1 (Jul 26, 2015)

jtrosky said:


> I've been noticing that when my tune sounds awsome sitting in the car without it running, it's not so great while driving down the road... While driving, I seem to have less bass... It's almost like you have to purposely "overdo" the bass a little to compensate for this...


Road noise is typically in the midbass region. It can also mask sub bass performance. Just a few extra db from 30 to 200hz helps a LOT.


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## jdunk54nl (Apr 25, 2015)

drop1 said:


> I understand. I'm just not one that tunes with the car off. I understand the merits but having measured the difference with the car on and off it makes no difference in my measurements.
> I drive a lot so I male tuning decisions while I'm driving. I make mental notes and apply them later.
> My system isnt built for sitting in the drive way type listening. My tune is setup to sound it's best while I'm on the road. It's a little bass heavy and little bright but sounds perfect at 60 mph.


Ya, I should just sit in it running this weekend and get it better. Maybe I will. I can then have a tune for running and one for not running later.


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> drop1 said:
> 
> 
> > I understand. I'm just not one that tunes with the car off. I understand the merits but having measured the difference with the car on and off it makes no difference in my measurements.
> ...


Are you wanting to compete? Or just wanting to see how good you cam get it sounding engine off?


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## jdunk54nl (Apr 25, 2015)

drop1 said:


> Are you wanting to compete? Or just wanting to see how good you cam get it sounding engine off?


No competition for me. While I like going to competitions to listen to others and don't mind giving demos of my truck (not at competitions but just when around friends), my goal of audio is not to do any of that but just enjoy it for me. 

I just am a constant tinkerer (with the DSP tune not equipment) and want it to sound the best possible and learn new ways of tuning and see how they change things.


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## JMikeK (Jan 2, 2019)

drop1 said:


> For sub, find a test tone in the crossover region. A tone beneath the mids high pass and subs low pass.
> 
> Play that tone amd turn your head side ways.
> 
> ...


This is 100% perfect of course, and actually quite a bit more sophisticated than my first swing. One thing I will add is that it is a bit like focusing a camera if you've ever done that before phones obsoleted the old 35 mm. So let's say you find that somewhere around 70 inches is the quietest, but you're not sure where to go exactly. Move it back until it gets noticeably louder, note that setting (e.g. 84), then move it forward until it gets noticeably louder again (e.g.: 66). Take the average of the two and that is your setting (e.g.: 75).


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## subterFUSE (Sep 21, 2009)

I still do impulse response and ETC for main speakers, and phase plot for subwoofer.

Absolutely nothing has done better for me and faster than these methods.

The more I use this method, the better I get at it and the better the results.


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## drop1 (Jul 26, 2015)

subterFUSE said:


> I still do impulse response and ETC for main speakers, and phase plot for subwoofer.
> 
> Absolutely nothing has done better for me and faster than these methods.
> 
> The more I use this method, the better I get at it and the better the results.


I've done my fair share brother. I quit when I started going this. Not because it was better but because after doing it this way and checking the results with messurmants, it's always silly close. 
This was just takes into account our individual head size and ear spacing. It's also so much faster and can be done by ear.


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## therapture (Jan 31, 2013)

drop1 said:


> My system isnt built for sitting in the drive way type listening. My tune is setup to sound it's best while I'm on the road. It's a little bass heavy and little bright but sounds perfect at 60 mph.



Amen! I found rather quickly that the tune that was awesome in the driveway, was thin and lacked the warmth at 75mph, especially in the midbass. I do a lot of tweaking on my commute now with a 35 minute drive.


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## Bnlcmbcar (Aug 23, 2016)

drop1 said:


> Flip the phase on the drivers side speaker.


Sorry if you explained it already but do you have any personal preference or theoretical reasoning for flipping the driver side vs the passenger side?


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## Holmz (Jul 12, 2017)

therapture said:


> Amen! I found rather quickly that the tune that was awesome in the driveway, was thin and lacked the warmth at 75mph, especially in the midbass. I do a lot of tweaking on my commute now with a 35 minute drive.


^That^ sounds like a quick route to an early rapture?
The worst part is you can take someone with you.

Like that Doors song... "keep your eyes in the road and you hands upon the wheel", or at least do not suggest it is something everyone should do.


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## Holmz (Jul 12, 2017)

drop1 said:


> ...
> How long the waves are has nothing to do with anything. That's some kind of odd science.
> 
> ...


^That weirdness^ seems consistent with the "windows of goodness" being wide, as noted below.




drop1 said:


> Maybe but there is a small window. There isnt 1 perfect click depending on the resolution. On the helix the window is about 12 clicks wide. I shoot for the center of that window.
> 
> With subs to midbass the windiw is much smaller but midbass to midbass has a pretty big window.


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## therapture (Jan 31, 2013)

Holmz said:


> ^That^ sounds like a quick route to an early rapture?
> The worst part is you can take someone with you.
> 
> Duly noted!


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## JCsAudio (Jun 16, 2014)

I gave this a shot for just the subwoofer to midbass transition in my truck and had to give the subwoofer a ridiculous amount of delay to get the test tone to null at the xover frequency. The midbass is marginally more up front now so it seems to work although I'm not sure why this is. I'm hoping I have more time this weekend to mess around with it and find out why.


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## drop1 (Jul 26, 2015)

JCsAudio said:


> I gave this a shot for just the subwoofer to midbass transition in my truck and had to give the subwoofer a ridiculous amount of delay to get the test tone to null at the xover frequency. The midbass is marginally more up front now so it seems to work although I'm not sure why this is. I'm hoping I have more time this weekend to mess around with it and find out why.


Phase. Sounds like you are 180 out of phase. The null will normally be near the same as tape would measure. 



Try again but dont flip the phase at the beginning. Just reduce the ta to zero on the sub with the phase you are in now. Slowly raise the ta to the first null, then flip phase. The ta should be closer to what you expect.

Also, what are your crossover settings on your subs and midbass? 24dblr's work best. 18 and 36 db slopes have odd phase alignments.


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## subterFUSE (Sep 21, 2009)

JCsAudio said:


> I gave this a shot for just the subwoofer to midbass transition in my truck and had to give the subwoofer a ridiculous amount of delay to get the test tone to null at the xover frequency. The midbass is marginally more up front now so it seems to work although I'm not sure why this is. I'm hoping I have more time this weekend to mess around with it and find out why.




If you are adding delay to the sub, then you are most likely doing it wrong. 

9 times out of 10 it is the front stage speakers that need delay added to match the sub. In other words, you want to take away delay from the sub to match it.

What I do when I tune is start all speakers with 10 ms delay and then I get remove delay from the sub.


Sent from my iPhone using Tapatalk


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## JCsAudio (Jun 16, 2014)

drop1 said:


> Phase. Sounds like you are 180 out of phase. The null will normally be near the same as tape would measure.
> 
> 
> 
> ...


I check phase as a standard practice with a polarity checker so I know for sure every speaker is in phase. I should recheck this though as I should double check. All my crossovers are 24 db LR4 and normally I have the subwoofer LP 1/2 octave lower than the midbass HP crossover. I never use any other slope because the acoustic response doesn’t match the electrical response well enough. Midbass are set at 80 Hz LR4. 



subterFUSE said:


> If you are adding delay to the sub, then you are most likely doing it wrong.
> 
> 9 times out of 10 it is the front stage speakers that need delay added to match the sub. In other words, you want to take away delay from the sub to match it.
> 
> ...


My case is not normal in that the left midbass is closer to me than the subwoofer because the subwoofer is right behind my seat so the left midbass has zero delay. All my other vehicles have delay added to the front stage to match the subwoofer because the subwoofer is the furthest away. This has been the toughest vehicle to get good up front bass where my other two vehicles have good up front bass. I got closer today though so we’ll see how it sounds on the way to work tomorrow.


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## subterFUSE (Sep 21, 2009)

JCsAudio said:


> I check phase as a standard practice with a polarity checker so I know for sure every speaker is in phase. I should recheck this though as I should double check. All my crossovers are 24 db LR4 and normally I have the subwoofer LP 1/2 octave lower than the midbass HP crossover. I never use any other slope because the acoustic response doesn’t match the electrical response well enough. Midbass are set at 80 Hz LR4.
> 
> 
> 
> ...




No. Even if the sub is nearest speaker you still need delay on the fronts. Crossovers rotate phase.

In my car the sub is the nearest speaker to the listener at 30 inches. My right side midbass is 62 inches. But the right side midbass is still delayed to the sub. Linkwitz 24 slope. 80 Hz.


Sent from my iPhone using Tapatalk


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## drop1 (Jul 26, 2015)

I ALWAYS use ta in distance mode not time mode. I want to "see" approx how each speaker is delayed. This also allows for me to add or subtract delays on subs. 
It just makes more sense to me and is much easier than calculating the difference in time between drivers.
Pioneer spoiled my with this when they introduced their ta in their head units.


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## JCsAudio (Jun 16, 2014)

subterFUSE said:


> No. Even if the sub is nearest speaker you still need delay on the fronts. Crossovers rotate phase.
> 
> In my car the sub is the nearest speaker to the listener at 30 inches. My right side midbass is 62 inches. But the right side midbass is still delayed to the sub. Linkwitz 24 slope. 80 Hz.
> 
> ...


Same here, right side midbass has delay (same as yours) in relation to everything else but the left midbass is the closest speaker so there is no delay on that one and delay on the subwoofer. 

Doesn't matter, obviously something is wrong and I will have to figure that out this weekend when I have more time to do so. I will start with the basics first and part of that is checking polarity. I may have a polarity issue from when I swapped the Pioneer 4 ch with the DLS 4 channel.


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## jdunk54nl (Apr 25, 2015)

JCsAudio said:


> Same here, right side midbass has delay (same as yours) in relation to everything else but the left midbass is the closest speaker so there is no delay on that one and delay on the subwoofer.
> 
> Doesn't matter, obviously something is wrong and I will have to figure that out this weekend when I have more time to do so. I will start with the basics first and part of that is checking polarity. I may have a polarity issue from when I swapped the Pioneer 4 ch with the DLS 4 channel.


Shouldn't the farthest away from you speaker have 0 Delay and the rest are delayed to match it's arrival time? So your right midbass should be 0 and your left should have delay? 

Otherwise I feel like your center would squished up to the left side


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## therapture (Jan 31, 2013)

This works pretty damn good! I have always found subs to be difficult to make work if you used pure distance. So I always just winged it by ear and moved TA around until it sounded the best and was upfront. Using nulling with a 75hz tone worked even better! Now the midbass to sub transition is even smoother.

I just added 5ms to all drivers then started working the sub down to less delay until it was obviously out of phase and ultra thin. Then with smaller ups and downs to verify the sweet spot. Flip phase back and boom. Bass in windshield and even better than my prior attempts.

Trying to listen to music and tweaking sub TA is difficult with so much going on with bass notes changing and what not. This is easier and had better results for me.


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## therapture (Jan 31, 2013)

JCsAudio said:


> Same here, right side midbass has delay (same as yours) in relation to everything else but the left midbass is the closest speaker so there is no delay on that one and delay on the subwoofer.


The FARTHEST away driver should be zero delay. The CLOSEST driver needs to be delayed to time it with the longer traveling wavefront from the farther side.


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## JCsAudio (Jun 16, 2014)

jdunk54nl said:


> Shouldn't the farthest away from you speaker have 0 Delay and the rest are delayed to match it's arrival time? So your right midbass should be 0 and your left should have delay?
> 
> Otherwise I feel like your center would squished up to the left side


Correct and good catch.


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## drop1 (Jul 26, 2015)

therapture said:


> JCsAudio said:
> 
> 
> > Same here, right side midbass has delay (same as yours) in relation to everything else but the left midbass is the closest speaker so there is no delay on that one and delay on the subwoofer.
> ...


I've always believed in delaying ALL drivers. I like being able to add or reduce delay on any channel at any time . Using distance instead of ms makes this very easy.


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## subterFUSE (Sep 21, 2009)

therapture said:


> The FARTHEST away driver should be zero delay. The CLOSEST driver needs to be delayed to time it with the longer traveling wavefront from the farther side.




Except with subwoofers because of the size of the waves and the phase offsets that occur with crossovers.

High frequency drivers need to be delayed to subwoofers, even when they are the same distance away, and many times when the subwoofer is closer. It depends on the crossover type and slope and frequency chosen.

I get best results delaying my entire front stage to match my sub. Phase plot alignment much better. More coherence across broader range of frequencies above and below the crossover.


Sent from my iPhone using Tapatalk


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## JCsAudio (Jun 16, 2014)

Ok, I couldn't take waiting until the weekend as it was going to drive me nuts so I made some time between my kids activities and something else to get out there and diagnose this with my polarity checker. I also busted out the good old tape measure and remeasured everything with the microphone strapped to the headrest. 

Thank you to jdunk54nl for asking me a simple but good question and helping me realize how simple some of these things can be. Thank you to drop1 for sharing this information and making understanding car audio better for everyone because the nuling works and I only had to make a small adjustment to the time alignment once I got everything correct as you stated. 

So I had a few issues that I'm going to blame on all the amplifier swapping and rushed incomplete tuning I've had for this vehicle over the last few months because I never seem to have enough time to finish what I started. First all the delays were backwards. The left and right sides were basically reversed so I basically had a passenger seat tune. Second the subwoofer was 180 degrees out of phase but the polarity checker was saying it wasn't, yet the RTA was showing a dip at the crossover signifying there was a phase issue. Once I covered the side firing port (ported subwoofer) the polarity checker finally read the polarity as correct. The back wave coming out of that port should only be 90 degrees out of phase with the front wave but for some reason I believe this messed up the polarity checker until I covered that port with my hand. This is a guess. I figured this out during the process for nulling when I flipped the phase thinking I was reversing it and all of a sudden the bass got better. 

Now the system sounds as good as the CX5 system and the bass is more up front instead of easily locating it behind me. The only thing I have to do now is turn down the gain on the amplifier for the tweeters because its a little too high (some noticeable amplifier hiss) and that can wait for the weekend because it sounds right now.

Thanks everyone again for your help.


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## jdunk54nl (Apr 25, 2015)

Hey, we all have those mistakes.

I just fixed my time alignment the other day. I have the easy entry/exit on my truck and I kept measuring distances without my keys in the ignition. Actually did it again the day I went to fix it and had to measure another time after coming inside and sitting down...5 minutes after I realized I did it again!

Turned out to be adding about 2-3" to my drivers side speakers and shifted my image to the left. Now it is better but my tune is still slightly off. Now I just need to have time to fix it.


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## therapture (Jan 31, 2013)

subterFUSE said:


> Except with subwoofers because of the size of the waves and the phase offsets that occur with crossovers.
> 
> High frequency drivers need to be delayed to subwoofers, even when they are the same distance away, and many times when the subwoofer is closer. It depends on the crossover type and slope and frequency chosen.
> 
> I get best results delaying my entire front stage to match my sub. Phase plot alignment much better. More coherence across broader range of frequencies above and below the crossover.


Gotcha, I was mostly referring to the front stage. In my F150, the sub is actually leading the mids in the time domain. 

To be clear to those that may not understand, ALL of my mids now have more delay than the sub does, meaning the signal hits the sub channel before any other.


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## tyroneshoes (Mar 21, 2006)

JMikeK said:


> Worked great on my sub and only took about 5 minutes with a youtube test tone. Lots of authoritative upfront bass and seamless midbass transition (using Pioneer's lovely 36 db/octave LP @ 80 Hz). Mostly the bass just sounds like music instead of something coming from the back of a car. No way I would have arrived at the setting I got without this method. Thanks! Plan to do the main drivers too soon, but that is a little more involved obviously.


What slopes are you using for rest of speakers? 24db LR?


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## JMikeK (Jan 2, 2019)

tyroneshoes said:


> What slopes are you using for rest of speakers? 24db LR?


I had experimented with 24 and 12 db high-passes with the 36 db LP. I am now using 24 all around. There are pros and cons in my mind, but 24 gives me a little more growl from the sub where 36 is just damned near a straight cutoff which sounds super-clean, but almost too clean for my preferences on some music.


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## Mahapederdon (Aug 19, 2016)

JMikeK said:


> tyroneshoes said:
> 
> 
> > What slopes are you using for rest of speakers? 24db LR?
> ...


Your in San Diego? Me too. Maybe sometime we can demo each other's stereos.


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## tyroneshoes (Mar 21, 2006)

question. 

I just tried this but Im a little unclear in the language used. Some are saying quiter and other are stating localized.

So this example. 

Sub and midwoofer with a 80hz 24db LR Low / High pass

play 80 hz sine wave

reverse the phase of the sub

volume match sub and woofer at 80hz then turn head sideways and move sub delay up and down so you can localize that woofers are coming from the front and the sub is coming from the rear the most? The most seperation?

Or to the point where it just kinda dissappears into your drivers side mid and is quiet as it is now upfront before flipping phase back?


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## JMikeK (Jan 2, 2019)

Mahapederdon said:


> Your in San Diego? Me too. Maybe sometime we can demo each other's stereos.


I am - It would be kinda fun to get together. I think that Patrick Bateman cat is out here too, but I could be wrong. I'll PM you my mobile.


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## drop1 (Jul 26, 2015)

tyroneshoes said:


> question.
> 
> I just tried this but Im a little unclear in the language used. Some are saying quiter and other are stating localized.
> 
> ...



There is a middle point. An 80 hz wave is LONG.

So if you go too far one way you'll hear your subs over your mids. Too far the other way and you'll hear your mids over your subs. The sweet spot is right in the middle. You cam kind of hear both equal in the front and back respectively. When it's just right, your ears will feel a little funny. That's the spot.


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## Patrick Bateman (Sep 11, 2006)

I'm kind of obsessive about getting the phase response correct with my speakers. I think it's a fundamental requirement for good imaging and articulate sound. Basically if you get the phase right, the two drivers sound like a single unit.



















Here's a measurement of one of my speakers IN phase and OUT of phase. Note the crazy deep null, which shows that they're basically 100% in phase at the xover point. 

This is with no DSP delay whatsoever, just careful selection of driver location and crossover points. This is how I do that: https://www.diymobileaudio.com/foru...cussion/163839-crossovers-step-further-5.html


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## dgage (Oct 1, 2013)

Can you take a close up of the baffle so we can see how that flows? Are your final speakers going to be cylindrical like that or will you transition to more of a “normal” speaker and if so, how do you address the baffle differences? Thanks for the link. Good read there.


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## Holmz (Jul 12, 2017)

Patrick Bateman said:


> I'm kind of obsessive about getting the phase response correct with my speakers. I think it's a fundamental requirement for good imaging and articulate sound. Basically if you get the phase right, the two drivers sound like a single unit.
> 
> 
> 
> ...


Was the Vandersteens playing to get the curve, or the bazooka looking thing?
Do you have a curve showing the 2c?


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## Mahapederdon (Aug 19, 2016)

I have a pair of those Vandersteen 2ce in my bedroom right now. Vandersteen reminds me of audiofrog. Only cause the owner is super cool and will help you directly with anything.


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## dgage (Oct 1, 2013)

Holmz said:


> ]
> Was the Vandersteens playing to get the curve, or the bazooka looking thing?
> Do you have a curve showing the 2c?


I was assuming a curve like that required bazookas. . That’s why I was wondering about the baffle as that driver integration is pretty special.


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## Holmz (Jul 12, 2017)

dgage said:


> I was assuming a curve like that required bazookas. . That’s why I was wondering about the baffle as that driver integration is pretty special.


Yeah, and there was a big red label on graph, but I want to see the 2c's curve...

I was telling someone about those a few weeks ago.


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## tyroneshoes (Mar 21, 2006)

drop1 said:


> There is a middle point. An 80 hz wave is LONG.
> 
> So if you go too far one way you'll hear your subs over your mids. Too far the other way and you'll hear your mids over your subs. The sweet spot is right in the middle. You cam kind of hear both equal in the front and back respectively. When it's just right, your ears will feel a little funny. That's the spot.


Thats kinda what i thought. Odd is I resulted with less upfront bass that seemed to move up to the dash when I reveresed the phase to where I found the most output from both woofers and sub that was easy to localize. Other part that was suprising was that the Pioneer Auto EQ gave me the same result (on sub delay) as my attempt at nulling. 

Are you making small adjustments at a time like just kinda adding .1ms or an inch at a time or making more wide changes due to the wave length? Or rapidly changing to where it becomes noticable that both are playing loudly, then go up and down by a step? 

Im doing a simple 3 way system with Pioneer network mode and trying to avoid dsp because I like my systems as simple as possible for the challenge. However, network mode can handle this correctly.

Am I wrong by flipping sub phase and should flip mid highpass?...very curious about the results I had. 

Curious how much delay this approach ended up on for you guys. In an imreza hatch, 76" in pioneer language is where I found what i though was the null lied. How much delay did you guys end up on?


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## drop1 (Jul 26, 2015)

tyroneshoes said:


> drop1 said:
> 
> 
> > There is a middle point. An 80 hz wave is LONG.
> ...


Keep in mind the amount of delay very much depends on what polairty you start in. When it comes out with some crazy number, I try again but do nat flip any phase at all in the beginning and start reducing delay until i find the sweet spot, then flip the phase. Doing it this way usually gives me a null at almost exactly the same point a tape measure would.

Lastly. To hell with pioneers auto eq. It is horrible for ta. It use to see nulls on the drivers side if my old explorer and would delay the drivers side over 100 inches while the passenger side would be about 30 inches. Then it would lower my mids crossover to 50hz and turn my subs all the way down. 
It also try's to tune perfectly flat . I lived the auto eq when I didnt know how to do things on my own but after learning I realize bow just how bad it really was.


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## tyroneshoes (Mar 21, 2006)

drop1 said:


> Keep in mind the amount of delay very much depends on what polairty you start in. When it comes out with some crazy number, I try again but do nat flip any phase at all in the beginning and start reducing delay until i find the sweet spot, then flip the phase. Doing it this way usually gives me a null at almost exactly the same point a tape measure would.
> 
> Lastly. To hell with pioneers auto eq. It is horrible for ta. It use to see nulls on the drivers side if my old explorer and would delay the drivers side over 100 inches while the passenger side would be about 30 inches. Then it would lower my mids crossover to 50hz and turn my subs all the way down.
> It also try's to tune pefectly flat . I lived the auto eq when I didnt know how to do things on my own but after learning I realize bow just how bad it really was.


In my experience the pioneer auto eq is horrible for eq and crossover point selection in network/active setups, but it seems right on the money for delay in this car. I run it just to see how it ends up and its much more effective and not that bad as a starting point for passive setups with no dsp. It was very similar to what the tracerite site gave me and gave a nice center image. I was just curious if this nulling approach would result in better sub-mid phasing. Typically I start off with 80hz and 2.5k hz 24db lp/hp and either 12 or 24db on bp and tweets and either flip or keep phase on sub same, which ever brings it up front more and has more output. Ive never really fine tuned subwoofer delay.

Example : Auto eq suggested 7" run from 80-8k and tweets from 8k up all 12 db and 80hz @ 18db on sub. That is just silly and it doesnt account for beaming and has a horrible curve goal. My tweeters fs is in the low 900s and the passives are fixed at [email protected] if I used them. I just saved first after initial tune because im always curious what it comes up with and you can shut it off, but the delay and crossover settings it comes up with sticks even if you turn auto eq off, so I can always revert to saved settings. This car auto-eq resulted in a better center image with its the auto eq delay settings and selected xovers off as I only delayed my drivers mid+tweet and the diff between passenger tweet and mid. Pretty similar to the tracerite site but it added delay to all speakers including the sub kinda right in the area I thought was the null at about 74".

But back to the topic, Ill try to revisit it again and see if Im missing somethin, but in my experience, it seems more like a peak than a null when both mids and sub at their most localaized and loudest. I know what you mean by the vaccuum in ear type of feeling in an acoustic null. Ill see if I can get that to happen.


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## Patrick Bateman (Sep 11, 2006)

dgage said:


> Can you take a close up of the baffle so we can see how that flows? Are your final speakers going to be cylindrical like that or will you transition to more of a “normal” speaker and if so, how do you address the baffle differences? Thanks for the link. Good read there.


Sure!










overhead view. This is with the waveguide cut in half.



















Had to nuke the project. The weight of the ribbon tweeter 'pulled' the upper half of the enclosure backwards.

It would work if I added some kind of structural reinforcement to keep the whole thing from bowing backwards. Nowadays when I 3D print things, I make the walls REALLY thick, like 1-2" thick. There's no real penalty for this, because the interior is hollow.


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## Patrick Bateman (Sep 11, 2006)

Holmz said:


> Was the Vandersteens playing to get the curve, or the bazooka looking thing?
> Do you have a curve showing the 2c?


The Vandersteen will never be able to get that kind of null, because the spacing is too long. Basically the Vandersteen 2C performs really nicely if you listen on EXACTLY the right listening axis. It has a very narrow vertical beamwidth, due to the wide spacing of the elements.

It's a nice speaker, no doubt, but my Unity horns are just on a whole 'nother level. If you play both of them at low level they will sound similar, because the design ideas are the same:

1) flat frequency response

2) very well behaved phase response. (Not flat, but no sudden jumps from driver to driver.)

But the Unity horns just get way louder.

(I *have* measured my 2Cs, and they're basically flat. They're a really nice design.)


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## jdunk54nl (Apr 25, 2015)

So I tried this tonight. 
Fairly easy on mids and subs. Tweeters are a little harder for sure. 

I still have some work to do but my center is definitely better.

One thing I did notice though. My tweeters to mid TA was like 2 clicks different for the right side compared to the left. What I mean is, to get my drivers side mid and tweeter to null the best I had to decrease the mids TA by 2 clicks. To get my passenger side to null the best, I had to increase the TA of the mids by 2-3 clicks.

Is this normal? I went with the middle ground. Is that the right approach?


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> So I tried this tonight.
> Fairly easy on mids and subs. Tweeters are a little harder for sure.
> 
> I still have some work to do but my center is definitely better.
> ...



I don't know about "normal" but your ta between the 2 on different sides should pretty much always be different. We are sitting in an asymmetrical spot in relation to the speakers.

Also, tweeters are a pain to ta without measuring impulse response.

They rely more on volume than anything. You could not ta them at all and still get decent results. That's how much dependent on volume they are. 

That being said, you do want them to image on top of your mids dead center.

Mute everything but your tweeters and play a dry vocal or some kind of dance music with a steady snare. Take note of where the snare is as far as center. Repeat with the mids. They should be in the exact same spot. If not, something is off.

If you feel like the phase relationship between the tweets and mids is good but you need to make an adjustment, try turning down whichever tweeter is pulling the center to the side. It doesnt take much. A db or 2 is usually plenty. This is called frequncy steering through on a wider level than normal. 

And yeah, the sub relies the most on phase so its easiest to do it.


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## jdunk54nl (Apr 25, 2015)

drop1 said:


> I don't know about "normal" but your ta between the 2 on different sides should pretty much always be different. We are sitting in an asymmetrical spot in relation to the speakers.
> 
> Also, tweeters are a pain to ta without measuring impulse response.
> 
> ...


Note: I currently have a 2way so these thoughts are based on that currently.

So this had me thinking, and I could be way off here but figured I would throw this thought out here.

Do we need to be playing pink noise with the tweeters only playing and trying to null them if volume is more important than T/A and due to its difficulty. 

Since tweeters are so hard, the subs and mids are fairly easy to T/A, and also mids to tweeters was easy to hear the null. Could we then do the following.

Use the tape measure to get the tweeters close and then just T/A them each to the passenger side mid using a test tone, as it is usually the farthest speaker from most people (ignoring subs right now) and the one we are T/A'ing to anyway. Then double check the driver side mid/tweet T/A. 

Finally fine tune the volume of the tweeters to get them centered appropriately.

This would also help with grouping stuff and moving them all in relation to TA.

You could group the mids after T/A. Then add the passenger tweeter to that group after you T/A it with the mids. Finally add the driver side tweeter after you T/A it with the mids. Otherwise you have your tweeters grouped and your mids grouped and I was fighting grouping trying to get the mids and tweets T/A'd. 

Once you have all 4 grouped and T/A'd you can then do the subs to that grouping.


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## screwfunk (Sep 26, 2017)

Hey Drop1, Check your PM. Want to talk audio production shop.


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## Holmz (Jul 12, 2017)

jdunk54nl said:


> ...
> 
> Since tweeters are so hard, the subs and mids are fairly easy to T/A, and also mids to tweeters was easy to hear the null. Could we then do the following.
> 
> ...


Technically one is not TA'ing them, they are "phase aligning" them.

If you do not have phase adjustment, then technically when the PA is correct, you will be off a touch in TA... whatever 90 or 180 degree (or less) is - in the wavelength of question.

In the olden days; if the phase was off then one would flip polarity and then be under 180 degrees.


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## jdunk54nl (Apr 25, 2015)

Holmz said:


> Technically one is not TA'ing them, they are "phase aligning" them.
> 
> If you do not have phase adjustment, then technically when the PA is correct, you will be off a touch in TA... whatever 90 or 180 degree (or less) is - in the wavelength of question.
> 
> In the olden days; if the phase was off then one would flip polarity and then be under 180 degrees.


Ya, I get that. Ultimately we are just trying to maximize the constructive interference in the waves and eliminate as much destructive as possible.

But instead of drop1's method of of nulling tweeters together, nulling mids together, then working on side pairs. 

Would it work and/or be easier to just null to the passenger side mid? Would it accomplish the same thing? Do we actually need to null all pairs of drivers?

My mind is saying there shouldn't be a difference but maybe I am missing something.


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## drop1 (Jul 26, 2015)

jdunk54nl said:


> Holmz said:
> 
> 
> > Technically one is not TA'ing them, they are "phase aligning" them.
> ...


Feel free to alter the method however you see fit.
Nulling like drivers is the absolute closest way to get something approaching measuring impulse response. A tape measure gets gou close, mulling gets you even closer.

I dont have a way so dont have drivers to null to there. The largest benifit by far for this is sub to mid bass alignment. Its guaranteed forward sounding bass. 

This wasnt meant to be an end all . 
In my original post I said something along the lines of "nulling is best, convince me otherwise).
This was meant to be a debate about approaches in which I hoped to learn more other methods. It was meant to be a conversation not a tutorial. I only posted my actual method because a few asked me to.


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## Holmz (Jul 12, 2017)

jdunk54nl said:


> Ya, I get that. Ultimately we are just trying to maximize the constructive interference in the waves and eliminate as much destructive as possible.
> 
> But instead of drop1's method of of nulling tweeters together, nulling mids together, then working on side pairs.
> 
> ...


Or use the LHS MB and null the RHS MB to it... then do both tweeters one at a time to the the single midbass, then do both woofer to the single reference...




drop1 said:


> Feel free to alter the method however you see fit.
> Nulling like drivers is the absolute closest way to get something approaching measuring impulse response. A tape measure gets gou close, mulling gets you even closer.
> ...


(A tone is actually the furthest thing from an impulse)
Is one is playing a tone, then nulling could be off by a whole wavelength and then still null. *Tones form an interference grating.*

It is only A closer and more precise measurement assuming that we are on the right cycle.
And That gets harder to ensure as we get towards the tweeters frequencies.


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## drop1 (Jul 26, 2015)

Holmz said:


> jdunk54nl said:
> 
> 
> > Ya, I get that. Ultimately we are just trying to maximize the constructive interference in the waves and eliminate as much destructive as possible.
> ...


I see where you are coming from. When I gave instruction I said to use a tape first. I assume everyone trying this method had had decent ts to start. The null should be VERY close to the measured ta. I just use the null to dial it in.
Then, you can use rew impuls to verify. 
I have a bunch. Nulling sounds better to me.

Now With this dirac live thing and the beautiful impulse it can create I'm sure that better. 

Using 24lr slopes the null and the impulse measurement should technically be the same amount of delay.


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## Holmz (Jul 12, 2017)

drop1 said:


> I see where you are coming from. When I gave instruction I said to use a tape first. I assume everyone trying this method had had decent ts to start. The null should be VERY close to the measured ta. I just use the null to dial it in.
> Then, you can use rew impuls to verify.
> I have a bunch. Nulling sounds better to me.
> 
> ...


Yeah you mentioned the tape first. But it deserved another mention.

It is great work you've done!


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## jdunk54nl (Apr 25, 2015)

Ya, I was assuming in my question that you measured with a tape measure and put that in first.


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## ballz50401 (Apr 14, 2018)

Great info here!

I decided to spend some extra time after work today playing with my sub TA. Looks like I was about 2.65 ms off compared to using the tape measure. My right midbass actually measured further away than my subwoofer, so I originally had it delayed to that. Now everything is delayed to the sub.


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## subterFUSE (Sep 21, 2009)

Yup. Tape measure does not work for subwoofers.


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## Babs (Jul 6, 2007)

subterFUSE said:


> Yup. Tape measure does not work for subwoofers.


Yep.. Subs are a funny animal.. Basically find the spot where they're in phase with midbass that's closest to their measured distance time-alignment point. It's not atypical to find subs will require a good bit less delay for that zero-phase point.

I would add it's not only a small challenge to get subs and midbass in phase at one frequency but if there is a large discrepancy in their delay times, their phase slopes will also be quite different in the bandwidth of the crossover region, so while you might easily get a sub and midbass drivers in phase at one point, say 80 hz, you may find them completely out of phase (180 degrees) at some other area such as 92 hz.. Bad. No Bueno.

So this is where delay time is essential not only for being in phase, but being in phase at the appropriate arrival time so their phase slopes are somewhat uniform (or parallel) between sub and midbass drivers in the region they're both playing, not just a single frequency. So you can't just delay out so the DSP thinks the sub is in the car behind you just because that's a point where the sub is in phase at 80 hz crossover point. The sub phase slope will be very steep compared to the midbass drivers, so you'll be just intersecting their phase slopes at 80hz but only at that point until the wraps come back around.

In short.. Start at measured distance delay time and stay close to that so you can attempt to achieve phase coherence throughout the full crossover region (bandwidth) such as 50-150 hz as much as possible.

Due props here: I learned all this stuff guys from Subterfuse among a few other key folks, who know their stuff big time. Credit where it's due.


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## Iamsecond (Jan 3, 2017)

Hey babs, I’m think I’m a pretty smart guy but can you bring that down a bit to a mere mortals understanding. I got lost a bit. Lol

So are you saying that his method will help get close where everything across the spectrum is in phase and time aligned?

also, we need to get together sometime and let me soak in some knowledge from you. We just sold our house and moved across town to your side of the tracks. We’re in fletcher/Arden area.


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## Babs (Jul 6, 2007)

Iamsecond said:


> So are you saying that his method will help get close where everything across the spectrum is in phase and time aligned?
> 
> also, we need to get together sometime and let me soak in some knowledge from you. We just sold our house and moved across town to your side of the tracks. We’re in fletcher/Arden area.


Yeah sometime it'd be fun for sure.. NCSQ meet coming up too.. I learned more in a day there than a year trying to read and figure it out, by getting around a bunch of guys with the same obsession. I am only beginning to learn.

Ok, so yeah the goal here is midbass and subs being in phase throughout the range they're both playing. A crossover point of say 80hz might have a range where both are audibly playing and hopefully complimenting each other from 50-200hz even. So you could be in phase at 80hz near where they should be timed based on distance measurement.. You could also be in phase at 80 hz at a full cycle of delay where sub has a bunch less delay than the mains. You'll want to prefer the closer to distance, because if you have a huge discrepancy of delay you'll likely be in phase only at that point where you lined it up with a tone. 

So the cliff's notes version: time it by distance to get it close, then phase it up by delay as well at smaller increments by tone and check with different frequencies near that tone.. 70-100 hz for example.

Want to have some fun for giggles.. Phase it in using the tone-polarity method, then keep going out in big delay incremements and you'll hear it go back then back out of phase in each direction. You'll be demonstrating the full 360 degree rotation of phase. What you won't see will be the phase slope increasing and increasing as you add delay which you can see if you do sweeps in Room EQ Wizard, but that's another topic.


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## Jumpngiggawattz (11 mo ago)

I just want to bump this thread for any new members out there. I tried this method to day with a Tune done by Helix Tune Eq on the new update and it's probably the best iteration I have had yet. Upfront bass is there and stage width is wide and center image is right where it should be, dab smack in the center of the dash. Just want to say thanks to the OP for this method this is my new favorite T/A method


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## MrHyde (Aug 31, 2019)

How would you go about time aligning a sub with mid bass that has the common nulls around 70-90Hz? I've watched Erin's video on using the sub to fill in the nulls and that has been helpful but I have never been completely satisfied with my results in blending the two. I'm not able to completely overlap the nulls with the sub since there is another null around 140Hz. No matter where I set crossover there is a null messing things up. So when I try to decide to use a 70, 80, or 90Hz tone for setting time alignment I wonder which is best since the sub crossover intersects the mid bass crossover right in the middle of a null.


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## ItsonlyaHONDA (Sep 9, 2021)

Jumpngiggawattz said:


> I just want to bump this thread for any new members out there. I tried this method to day with a Tune done by Helix Tune Eq on the new update and it's probably the best iteration I have had yet. Upfront bass is there and stage width is wide and center image is right where it should be, dab smack in the center of the dash. Just want to say thanks to the OP for this method this is my new favorite T/A method


Lol I think the op was banned, don't know why. 🤣 but yes time alightment is key. I have 2 subs one in my trunk and one in my passenger footwell. I had this terrible null between both at 65hz and the auto tune could not fix it and I kept moving the crossover points to see if it would fix it but the null just shifted either direction. I then realized that I accidentally moved my time alightment some how. I still don't know how and when. But after I re-did my time alightment I had a massive boost at 65hz that needed to be cut from both subs.


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## ItsonlyaHONDA (Sep 9, 2021)

MrHyde said:


> How would you go about time aligning a sub with mid bass that has the common nulls around 70-90Hz? I've watched Erin's video on using the sub to fill in the nulls and that has been helpful but I have never been completely satisfied with my results in blending the two. I'm not able to completely overlap the nulls with the sub since there is another null around 140Hz. No matter where I set crossover there is a null messing things up. So when I try to decide to use a 70, 80, or 90Hz tone for setting time alignment I wonder which is best since the sub crossover intersects the mid bass crossover right in the middle of a null.


What kind of vehicle? Big sedans like my accord have massive nulls from 65 to around 100 that the rear sub and door mounted midbasses cannot do anything about. And if your anything like me that frequency range is important to have some nice chest slaps, along with everything else of course. But if there is a big null there no matter how much output your subs and mibasses have your going to be laking. My solution was a front sub playing only in tha region with massive amounts of power of course because "I have issues". 🥴


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## dumdum (Feb 27, 2007)

ItsonlyaHONDA said:


> Lol I think the op was banned, don't know why. 🤣 but yes time alightment is key. I have 2 subs one in my trunk and one in my passenger footwell. I had this terrible null between both at 65hz and the auto tune could not fix it and I kept moving the crossover points to see if it would fix it but the null just shifted either direction. I then realized that I accidentally moved my time alightment some how. I still don't know how and when. But after I re-did my time alightment I had a massive boost at 65hz that needed to be cut from both subs.


In reality you needed to measure both drivers and adjust crossovers to get 6db down points to match, then set ta correctly and you’d have got the same result

If you got a sum that created a peak your crossovers were set wrong or needed eq to correct the phase response through the crossover


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## ItsonlyaHONDA (Sep 9, 2021)

dumdum said:


> In reality you needed to measure both drivers and adjust crossovers to get 6db down points to match, then set ta correctly and you’d have got the same result
> 
> If you got a sum that created a peak your crossovers were set wrong or needed eq to correct the phase response through the crossover


I used that method because if I cross my front sub less than 65hz I can bottom them out with the power I'm sending them(almost double its rated RMS). So I chose the crossover based on what the front sub was comfortable playing, unconventional? Yes, but ive had very little time tunning but I am happy to try different ways. I haven't even taken measurements of each individual driver yet. I just let the auto tune do its thing in the little time I have in my jobs parking lot between shifts. Maybe 20 min at a time, if that. I did the auto tune on the left 3 way, right 3 way, the 2 way centre, then the 2 subs together, then the right side with the subs then the left side with the subs. I got all of those auto tunes to give me that message where it tells me that the deviance's? were met. I haven't done everything together yet but it sounds amazing already to me. I'm still new to tuning, like very new and I wish I had more time to spend in my car but I work with what I have.


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## subterFUSE (Sep 21, 2009)

Phase plot is the best method to align subs and midbass.

[/endthread]


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## Jumpngiggawattz (11 mo ago)

subterFUSE said:


> Phase plot is the best method to align subs and midbass.
> 
> [/endthread]
> 
> ...


Do you mean like in Smaart? The reason I ask I know the Jl tuning app is built off of Smaart and I did download that, so can I measure phase with that or is that only if you have Jl amps?


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## subterFUSE (Sep 21, 2009)

Smaart, SysTune, REW, JL Audio TuN. They all can do phase plot. 


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## SkizeR (Apr 19, 2011)

Jumpngiggawattz said:


> Do you mean like in Smaart? The reason I ask I know the Jl tuning app is built off of Smaart and I did download that, so can I measure phase with that or is that only if you have Jl amps?


You can measure phase all sorts of ways. With an interface that has a loopback (many different software can do this), or REW with its reference signal if you have a USB mic. I rarely find this necessary though as I can typically nail it easily with REW's RTA by monitoring the summation between crossovers.


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## Jumpngiggawattz (11 mo ago)

SkizeR said:


> You can measure phase all sorts of ways. With an interface that has a loopback (many different software can do this), or REW with its reference signal if you have a USB mic. I rarely find this necessary though as I can typically nail it easily with REW's RTA by monitoring the summation between crossovers.


So essentially if you are seeing 6 db or pretty close to it in the crossover region your phase is in good shape?


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## SkizeR (Apr 19, 2011)

Jumpngiggawattz said:


> So essentially if you are seeing 6 db or pretty close to it in the crossover region your phase is in good shape?


Depends on the crossover type. But this is one reason why I stick to a Linkwitz 24dB target.


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## subterFUSE (Sep 21, 2009)

Jumpngiggawattz said:


> So essentially if you are seeing 6 db or pretty close to it in the crossover region your phase is in good shape?


Not necessarily. The nulling method only tells you if you are in phase at one frequency. Phase plot shows you a wide range of frequencies. 


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## Jumpngiggawattz (11 mo ago)

So far I have only tuned to 4th order LR xovers myself even though I don't always use them for the electrical setting in the dsp. I have been thus far using whatever crossover takes the least eq to hit my individual curves.


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## Jumpngiggawattz (11 mo ago)

subterFUSE said:


> Not necessarily. The nulling method only tells you if you are in phase at one frequency. Phase plot shows you a wide range of frequencies.
> 
> 
> Sent from my iPhone using Tapatalk


I didn't mean with the nulling method necessarily, I just meant if you are seeing good summation on the RTA frequency response that is a good indication of good phase at the crossover region. I really want to get a better idea of phase and how to measure it properly ideally in real time if possible. I think this can bring me to the next level of tuning. I learn more all the time and especially everytime I am tuning whether it be my car or a friend's. I find myself offering to tune others cars just to help them and increase my grasp on it better with different circumstances in different vehicles. I really think that at some point I may reach out to Nick for a remote if only to learn some more myself because I realize that people with knowledge of this aspect of car audio is few and far in between.


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## MrHyde (Aug 31, 2019)

ItsonlyaHONDA said:


> What kind of vehicle? Big sedans like my accord have massive nulls from 65 to around 100 that the rear sub and door mounted midbasses cannot do anything about. And if your anything like me that frequency range is important to have some nice chest slaps, along with everything else of course. But if there is a big null there no matter how much output your subs and mibasses have your going to be laking. My solution was a front sub playing only in tha region with massive amounts of power of course because "I have issues".


Yea, same issue with my Fusion sedan and same nulls. The front sub is a good solution. I have my sub in the rear floor foot well. I'm able to blend it better in that location and use it to semi-fill in the nulls without too much stage pulling. These nulls are such a major issue in car audio.


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## ItsonlyaHONDA (Sep 9, 2021)

MrHyde said:


> Yea, same issue with my Fusion sedan and same nulls. The front sub is a good solution. I have my sub in the rear floor foot well. I'm able to blend it better in that location and use it to semi-fill in the nulls without too much stage pulling. These nulls are such a major issue in car audio.


From what some one with more experience told me is that the sedans have a cabin gain from 65hz and down. That plus the null in that area makes it double the trouble. But after going front sub I'll probably never go back


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## subterFUSE (Sep 21, 2009)

Sometimes the null can be fixed with all pass filters. Phase measurements are critical to determine that. 


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## jdunk54nl (Apr 25, 2015)

subterFUSE said:


> Sometimes the null can be fixed with all pass filters. Phase measurements are critical to determine that.
> 
> 
> Sent from my iPhone using Tapatalk


That is only a null between two drivers that can be fixed by an all pass. You can't fix a null due to install location and reflections from an individual driver response.

Also, if anyone wants to try out a free version of smaart, check out open sound meter. Great little program. I still prefer smaart, but open sound meter is pretty good.

If nulling is your method of choice to fix phase between subs and midbass drivers, play band limited pink noise that is throughout the crossover region. REW can easily generate this. That way you are not just getting phase correct at a single frequency. You can easily mess things up this way by getting phase correct at that frequency but the timing could still be way off. You may have more/fewer wraps in one driver compared to another which would give you a false positive. You can be in phase and out of time, you can be out of phase but in time, but you want both of these (in phase AND in time) If you don't know what this means, look at these:



https://www.merlijnvanveen.nl/en/study-hall/166-subwoofer-alignment-the-foolproof-relative-absolute-method


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## ItsonlyaHONDA (Sep 9, 2021)

I'm sure the null can be fix through phase n such but most of us don't have the know how. At least I don't. But I do know that door mounted midbasses will never bring the impact a front sub will. I can care less if my midbasses can fill the null, will that make my mirrors shake and give me goosebumps without my rear sub playing. I highly doubt it. At least not in the doors of my accord. I'm happy with a front sub and how it makes me feel.


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## MrHyde (Aug 31, 2019)

jdunk54nl said:


> If nulling is your method of choice to fix phase between subs and midbass drivers, play band limited pink noise that is throughout the crossover region. REW can easily generate this. That way you are not just getting phase correct at a single frequency. You can easily mess things up this way by getting phase correct at that frequency but the timing could still be way off.


I like this idea. That makes sense. I used a 70Hz tone to time align my sub and mid bass last time and I thought I had it blended nice until I started listening to some of my usual music. Then realized other frequency ranges had gotten worse. Another thing I've done is run my RTA "live" with no averages while playing full bandwidth correlated pink noise and adjust sub time alignment while watching for the deepest null in the crossover region. Sometimes after setting time alignment on sub I'll mess with the subs phase setting, the separate button on the DSP for phase. Is it better to adjust the phase before or after adjusting distance?


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