# Proper time alignment



## Umaronly (Jun 27, 2008)

hi everyone. i have been trying to use my alpine 9887 hu to align my front components and sub in the trunk. i mute my right speaker and listen to any track to delay the left component versus the sub to get good bass. then i delay the right speaker so that the image comes right in front of me. however, this always results in poor bass extension and kick versus when there is no alignment done. i think i am not doing this the right way, specially when i align the sub with the left components. can anyone pls guide me on this? i don't have rear fill


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## RedGTiVR6 (Jun 26, 2007)

time alignment is mostly just a calculation.

Time Delay (in seconds) = Distance/Speed (of sound in air).

The speed of sound in air is approximately given by the following equation:

V sound in air = [331.4 + 0.6 Tc]m/sec

Where Tc is the Celsius temperature.

At an ambient temperature of 22 deg. Celsius (72F), the speed of sound in air is 345m/s or 1132ft/sec.

Humidity a slight factor.
An increase in the amount of humidity in the air increases the speed only small amount. Since humidity can vary so much, and since the amount of change of speed with an extreme change in humidity is less the 0.5%, the speed of sound in air is usually simply measured in dry air, neglecting the effect of humidity.

Pressure not a factor.
Counter to intuition, changes in air pressure have no real effect on the speed of sound. Sound travels slower at higher altitudes because the temperature and relative humidity are lower, not because the air pressure is lower higher altitudes.


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## mvw2 (Oct 2, 2005)

Tape measure.

That'll get you close as a starting point, at least within a couple notches of ideal. Then tune by ear from there. If the tape measure and your ear match each other well, you're dead on or at least pretty close.


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## Umaronly (Jun 27, 2008)

thanks for the answers, i know what time alignment is, am an engineer. what i meant was that i could not 'hear' the blending of the sub with the front components well enough to be able to align them satisfactorily. i can align the front components very well, since i can hear the image moving in front of me, but the sub is giving me trouble. in addition, i am just adding delay to the left and right front channels versus the single sub which is farthest to the seat, but the alpine also gives the option of setting delay for the left and right subs. firstly, i only have one sub so cannot understand which sub channel to adjust. secondly, if i only need to adjust for the relative difference, why is there an option to adjust the subs?


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## 14642 (May 19, 2008)

No need to account for temperature, since it'll affect the souns from all the speakers --consider it a constant and the effect is so small it's moot.

There's really no need to align the speakers to the subs. Bass up front can be had with proper EQ. In any case, if you decide to align to the subs, you'll have to do it by ear. Adjust the delay for all the other speakers, but you'll have to overshoot the measurements made with the tape measure.

Trust me...


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## MuTT (Apr 4, 2007)

Umaronly said:


> secondly, if i only need to adjust for the relative difference, why is there an option to adjust the subs?


Just so you know, the sub is not the furthest driver away in everyone's set-up


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## matt62485 (Jun 7, 2008)

so when using a tape measure, where exactly do you measure from and where to??? like diagonally... etc. i have my mids in my doors and tweets in my kicks. im running a 9887 as well active. i have in in 4way mode obviously... on the t/a it has FL and FR, RR and RL and SL and SR, since the mids are hooked to the rear (i think thats how it goes) and the tweeters to the front preouts... will adjusting the rear left and right on the t/a adjust the mids? ive never played with that honestly.


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## Oliver (Jun 25, 2007)

Try from your receivers to your senders 

Ears - to - speakers


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## RedGTiVR6 (Jun 26, 2007)

from the center of each speaker to the tip of your nose. Add a few inches to account for the distance from the tip of your nose to the middle of your head between your ears.

If you're aligning for two seat, measure to the middle of the car directly between the two listeners, at ear level.


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## Hillbilly SQ (Jan 26, 2007)

MuTT said:


> Just so you know, the sub is not the furthest driver away in everyone's set-up


It's the CLOSEST driver in my install


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## matt62485 (Jun 7, 2008)

i wish someone lived around here that knew this stuff better than myself. most people around here look at me like im retarded when i say im running active... huhhhhh!?


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## Umaronly (Jun 27, 2008)

Thanks for the answers people, really helped. will let you know when i do this. just for information i am running a passive system and cannot adjust the front mids and tweets independently, so syntle appreciate if you could tell me how to adjust in this scenario.


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## RedGTiVR6 (Jun 26, 2007)

Are they mounted close to one another?

How much of a difference is there between them?

If they are close, just measure between the two and use that measurement for your time alignment.

Makes me think I should upload my spreadsheet I made for this....lol


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## subwoofery (Nov 9, 2008)

Andy Wehmeyer said:


> ... There's really no need to align the speakers to the subs. Bass up front can be had with proper EQ. ...


I was just wondering which frequencies are we talking about? Pretty sure it is the midbass but not so sure lol. Would that be 100hz to 400hz?


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## gijoe (Mar 25, 2008)

How much does the speaker wire play into this? Say that my amp in mounted on the left side of my trunk, so my right wires are a couple of feet longer than the left. How much difference in the length of the wires does there need to be in order to effect the time alignment? Obviously a couple of inches isn't going to make a difference, but will a couple of feet make enough difference that it needs to be taken into consideration?


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## RedGTiVR6 (Jun 26, 2007)

considering that electrons travel at the speed of light when electricity is concerned, a few feet isn't going to make a lick of difference. If we were talking about miles....and by miles I mean a lot of miles, then you would have something to worry about.


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## matt62485 (Jun 7, 2008)

i think with one mile u have very minute difference. we did this in class oneday, it wasnt very much to concern... but after about 15 or so it seemed to get very noticable IIRC


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## BoostedNihilist (Mar 3, 2008)

A bit off topic.

If cooler air is more dense than hot air (I.E. intake charge) and density has an impact on sound waves (I.E. sound in water) then how exactly is temp a non-factor?


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## gijoe (Mar 25, 2008)

BoostedNihilist said:


> A bit off topic.
> 
> If cooler air is more dense than hot air (I.E. intake charge) and density has an impact on sound waves (I.E. sound in water) then how exactly is temp a non-factor?


I believe because those elements are constant across every speaker. The humidity changes the timing for every speaker more or less equally. Each speaker may react slightly different to these changes, but the difference is insignificant.


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## vecc205 (Nov 18, 2007)

Andy Wehmeyer said:


> No need to account for temperature, since it'll affect the souns from all the speakers --consider it a constant and the effect is so small it's moot.
> 
> There's really no need to align the speakers to the subs. Bass up front can be had with proper EQ. In any case, if you decide to align to the subs, you'll have to do it by ear. Adjust the delay for all the other speakers, but you'll have to overshoot the measurements made with the tape measure.
> 
> Trust me...


Andy can you explain why this is so? Is it because if the sub is properly balanced you shouldn't hear it coming from the back? I find if I don't time correct the sub it may sound ok but will sound better with the time correction. Thanks.

Kyle


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## RedGTiVR6 (Jun 26, 2007)

it's not a factor in normal every day temperatures. It takes extremes to make a difference big enough that most tuning options in a car can comprehend.

Try it yourself, plug in the temperatures in the formula and you'll see why.


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## Umaronly (Jun 27, 2008)

People, slight issue. Having time aligned the components (fronts), the image seems to be out of focus. Moving the components closer to me further away, I can hear the image moving from one direction to the next but when it comes near directly in front of me, it gets confusingly disturbed where the sound is coming 'somewhere' from the dash in front but wanders....suggestions? ( I have not time aligned the sub as yet)


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## 14642 (May 19, 2008)

There are a couple of issues here.

Sounds that are recorded so they appear in the center are mono. That means they are precisely the same in both channels. In order for you to hear them in the center, your ears have to hear precisely the same sounds from both of the speakers. Since you can't sit in the middle of your car, time alignment can fix this issue for one seat. Remember, you have to hear precisely the same thing from each speaker--that means the levels from left and right have to be the same AT EVERY FREQUENCY. Time alignment is a very easy thing to adjust--measure the distances and enter the numbers. If you have to convert to time, then do the math and enter the numbers. That'll get you close enough. Precisely matching frequency response and level is NOT AN EASY THING TO DO. In a car, 4 or 5 bands of parametric EQ aren't enough. You MUST have separate EQ for left and right and unless you're Supertweaker, plan to spend a long time over several sessions to get it right. 

Setting time alignment and then wondering why the center image isn't rock solid is only doing half the job.

Also, when you get this right, expect that you'll have to spend some tiime getting used to what you hear. In most modern recordings, MOST of the information is recorded in mono or damn close. The center image will be loud and you won't hear the right and left speakers. That's a tough thing to get used to and even IASCA judges have a hard time with it. They say things like "Wow, the center channel is too loud, The stage is narrow...blah blah blah...".


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## RedGTiVR6 (Jun 26, 2007)

do you have individual Right and Left EQ possibilities?


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## Umaronly (Jun 27, 2008)

nopes.


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## RedGTiVR6 (Jun 26, 2007)

Then you're kinda at your limit right now.

As Andy points out above, you need the individual R/L EQ adjustments in order to take this any further.

Time to upgrade your processing capabilities!


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## subwoofery (Nov 9, 2008)

Andy Wehmeyer said:


> ... There's really no need to align the speakers to the subs. Bass up front can be had with proper EQ. ...





subwoofery said:


> I was just wondering which frequencies are we talking about? Pretty sure it is the midbass but not so sure lol. Would that be 100hz to 400hz?


Quoting myself lol 

Anyone?


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## RedGTiVR6 (Jun 26, 2007)

not sure I understand your question.

Andy is talking about subbass and you're talking about mid bass....can you clarify?


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## subwoofery (Nov 9, 2008)

Yes I know but I always thought that you can bring sub frequencies upfront by playing with the midbass EQ... unless... 
That is why I asked, if there are specific frequencies that you can manipulate for the subbass, then I'm all open to hear it


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## 14642 (May 19, 2008)

be sure there's no huge peak at 45Hz and make sure the transition from 60Hz-160Hz is smooth. The response should be flat from 60Hz through the midrange.


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## vecc205 (Nov 18, 2007)

Andy Wehmeyer said:


> There are a couple of issues here.
> 
> Sounds that are recorded so they appear in the center are mono. That means they are precisely the same in both channels. In order for you to hear them in the center, your ears have to hear precisely the same sounds from both of the speakers. Since you can't sit in the middle of your car, time alignment can fix this issue for one seat. Remember, you have to hear precisely the same thing from each speaker--that means the levels from left and right have to be the same AT EVERY FREQUENCY. Time alignment is a very easy thing to adjust--measure the distances and enter the numbers. If you have to convert to time, then do the math and enter the numbers. That'll get you close enough. Precisely matching frequency response and level is NOT AN EASY THING TO DO. In a car, 4 or 5 bands of parametric EQ aren't enough. You MUST have separate EQ for left and right and unless you're Supertweaker, plan to spend a long time over several sessions to get it right.
> 
> ...


Please correct me if I'm wrong but I believe you are referring to midbass/midrange and tweeter on the left side compared to the right side? I'm not to sure what you mean when you said you don't need time correction on the subwoofer. Maybe theres something I overlooked.


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## 14642 (May 19, 2008)

vecc205 said:


> Please correct me if I'm wrong but I believe you are referring to midbass/midrange and tweeter on the left side compared to the right side? I'm not to sure what you mean when you said you don't need time correction on the subwoofer. Maybe theres something I overlooked.


 
Yes, basically, you want to un-equalize the pathlengths you've just equalized with TA. Smaller changes will effect high frequencies. Big changes will affect lower frequencies. Correcting for the sub is sort of the decoration on the cake's icing. It's a tiny bit helpful, but matching levels, tuning the response and eliminating rattles and distortion in the sub are the most important parts of getting the bass up front. A 50Hz wave is 20 feet long. Correcting for a few inches of PLD between the midbass and the sub isn't enough degrees of phase shift to make much of a difference.


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## mvw2 (Oct 2, 2005)

It'll depend upon frequency. If you cross at 50Hz versus 100Hz, there will be some additional benefit gained for the 100Hz x-over setup using TA. I agree the sub isn't major, but it is still noticeable to some extent. As well, the sub does still play and fill in information well above the x-over point, especially with shallower slopes. This will depend upon the sub, but some "musical" subs on a shallow -6dB/oct. slope will be playing midrange information upwards of 600Hz to even 1kHz. Again, this is all depending on the setup, sub, slope choice, etc. but TA can improve or hinder the coherency of the bass resposne so some extent. TA on a sub can be ignored for the most part, but it really shouldn't be because there is room to gain.

A quick recap of some that has been discussed in my own experiential spin:
-TA is a mechanical tool. It's a set it right once and forget it thing. If the distance is right, it's right. If the sound is off, it's another issue. (big wink )
-TA can influence dominance, i.e. what your mind considers more important because it reached your ears first.

-SPL levels also create dominance. What is louder is more important.
-Level adjustment and TA can be interchanged to a relatively large extent in moving dominance around. It is incorrect to use one in place of the other, but they both achieve a similar end result to our minds.
-The goal is to balance raw levels between drivers so no one driver overshadows the other.

-SPL over the entire bandwidth (frequency response) is an application of the level balancing over the entire frequency range. If balanced, no one side will overpower the other and the center will be exact and unmoving. This is highly aided through the use of separate L and R EQing.
-Matching frequency range response between left and right fixes a wandering center image.

This is a tuning guide I wrote out a while ago. This is the best way I know how to tune a system that works pretty easily and yields very good results on even just one attempt, although tweaking or running through the process several times is not a bad thing really.
http://www.diymobileaudio.com/forum/diyma-tutorials/33149-mini-tuning-guide-active-user.html
I have never been unhappy with this method. The guide covers a lot of the points made through this thread as well and kind of what you should be shooting for.


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## matt62485 (Jun 7, 2008)

ive been messing with my TA after reading this thread vigourously... im running 2 way and i notice that adjusting my mids are a lot more audible to where the sound moves than the tweeters... would that be bc my tweeters are closer to be on axis than my mids? i also noticed that on some songs (i dont listen to rap much, but i was testing some stuff out) such as lil jon the stage seemed more around the 2 center vents area right at the top of my dash... oppossed to sarah mclachlan where the stage was more around the area 6" below the rearview mirror, virtually about mid windshield... i notice the height shifts on certain types of music... is this just the way its recorded? i also notice that rolling my windows down causes the stage to drop slightly, as well, regardless of the genre or recording. is this typical? or do i have some other underlying issues i need to resolve? i realize it wont be great bc my mids are firing at each other in the doors, and the tweets are a few degrees off axis in the kicks (will be aiming them soon)


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## RedGTiVR6 (Jun 26, 2007)

matt62485 said:


> ive been messing with my TA after reading this thread vigourously... im running 2 way and i notice that adjusting my mids are a lot more audible to where the sound moves than the tweeters... would that be bc my tweeters are closer to be on axis than my mids? i also noticed that on some songs (i dont listen to rap much, but i was testing some stuff out) such as lil jon the stage seemed more around the 2 center vents area right at the top of my dash... oppossed to sarah mclachlan where the stage was more around the area 6" below the rearview mirror, virtually about mid windshield... i notice the height shifts on certain types of music... is this just the way its recorded?


A center image will vary on every recording. There's no industry standard that states where a center image should be.

For instance, Hotel California...everyone thinks the main vocal should be centered....it's not...it's left of center.

Stage height will also determine where the center is. Depth to stage and depth of stage will also be a determining factor.



> i also notice that rolling my windows down causes the stage to drop slightly, as well, regardless of the genre or recording. is this typical? or do i have some other underlying issues i need to resolve?


Your windows are reflective. When you work the time alignment with those reflective things in the way, then you remove those reflective surfaces, of course it's going to change things.



> i realize it wont be great bc my mids are firing at each other in the doors, and the tweets are a few degrees off axis in the kicks (will be aiming them soon)


I just want to verify this....you're not saying that you're planning on adjusting your tweeters simply because they ARE off axis, are you?


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## matt62485 (Jun 7, 2008)

RedGTiVR6 said:


> A center image will vary on every recording. There's no industry standard that states where a center image should be.
> 
> For instance, Hotel California...everyone thinks the main vocal should be centered....it's not...it's left of center.
> 
> ...


*well, my left tweeter is virtually aiming at my leg, i shouldve clarified more. my right tweeter is closer to being on axis, its just the way the kicks angle in my car and where i mounted the tweeters. if i wanna put my left foot over a little bit, the stage it completely thrown off. if i aim them on axis, it'll fix that the way i decide to do it. plus, i was doing some tinkering the other day aiming them from what appeared to be on axis-ish by my eyes and it sounded better that way to me. otherwise, id leave em, but i cant stand keeping my left leg tucked to the right just so it wont hinder the performance
ps- thanks for the reply *


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## 14642 (May 19, 2008)

Time alignment is less critical at high frequencies because we use level at high frequencies to determine the location of sounds. We don't perceive ITD at high frequencies because the wavelengths are too short.


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## matt62485 (Jun 7, 2008)

Andy Wehmeyer said:


> Time alignment is less critical at high frequencies because we use level at high frequencies to determine the location of sounds. We don't perceive ITD at high frequencies because the wavelengths are too short.


damn, good point. that explains a few things. thanks.


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## Hernan (Jul 9, 2006)

It's not rocket science... just add a bit of delay to you Left woofer until the bass comes from the center with good definition.

T/a has little effect at high frecuencies. Polarity changes HAS an effect and, of course amplitude.

Focus is about equal frecuency response and time arrival from L&R. (Practically imposible in a car. Yes, you could get it close)

When you are running 2 ways, delaying the woofer is more tricky.
Play attention to tonallity changes in the lower midrange. I found this more important than a perfect centered midbass than can be fixed with a bit of EQ.


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## mvw2 (Oct 2, 2005)

Tweeter TA is less important with stage position a little bit. It'll still create a dominance issue and pull one way or the other.

The other important factor when TAing is syncing the tweeter with the woofer. For example, if you cross at 3kHz, to get a coherent blending over the 3kHz range, you need the woofer and tweeter synced together. If they are not, there will be some noticable separation there.

In reality, these are all small details. To the casual listener, they are not vast changes. Well, sometimes. Sometimes they have a rather big influence on the end sound actually. I'll clarfity a little bit. It's install dependent. As well, the difference between close and exact isn't major. Still, being exact will yield the better believable end result where you can start to really "see" the music. The actual "seeing" of the sound stage does sort of require all the parts to largely fall into place. The believability comes from moving from close towards exact in setup.


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## tgnylu (Aug 28, 2009)

I know I'm chiming into this thread a bit late, but I'm surprised no one has asked more details about this:



RedGTiVR6 said:


> Depth to stage and depth of stage will also be a determining factor.


Maybe I'm the only one that doesn't know, but how do you adjust depth of stage and depth to stage? I'm sure the general answer is "with EQ," but a bit more detailed info from anyone that knows would be much appreciated!

And thanks for the great posts RedGTiVR6 and Andy Wehmeyer


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## PaulD (Nov 16, 2006)

good luck getting RedGTi to answer, she stopped coming on here like 6+ months ago, Andy W still stops by ocassionally. This thread is 1 year old - of course if you had just started a new thread, it would have ended up in the "you should have searched first" iggy bin. You are expected to do a search and read all 5000+ pages of every thread that contains the words depth and stage .......


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## I800C0LLECT (Jan 26, 2009)

ant said:


> Hi Umaronly
> 
> here we go,
> 
> ...



That's a nice way of explaining the method


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## I800C0LLECT (Jan 26, 2009)

I've read somewhere before that stage depth can involve certain frequencies. Ever notice that by changing mid-range response you can muffle the singer, make them sound as if they're standing in your face, or even 100 yards away?

My presumption would be that recordings have a lot to do with stage presence as well. Fundamentally you tune for what you like and put up with everything else in the mean time or only listen to those songs over and over  It's another reason why some of the nicer EQ's save so many presets.


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## jbholsters (Jun 17, 2009)

tgnylu said:


> how do you adjust depth of stage and depth to stage? I'm sure the general answer is "with EQ," but a bit more detailed info from anyone that knows would be much appreciated!


Try dropping 5K


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