# Myth: You can achieve proper center image WITH T/A



## asota (Feb 7, 2011)

I know this may stir up some controversy but a true center image should be in the center of dash regardless of where you are in the car if you are in drivers seat, passenger seat, or laying on the back seat a true center image should be in center of the dash. I know there are some good 2-seat cars using T/A with center channel, but the best ones use optimum speaker placement and really didn't need much if any T/A to begin with. The only dead perfect center image (two seat) cars I have ever heard had no T/A whatsoever, but had many many hours of optimum speaker placement and tuning. T/A is a easy and convenient way to achieve one point center image but is that true center image when if you move your head 6 inchs the image changes?


----------



## chefhow (Apr 29, 2007)

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/62466-where-exactly-should-center-located.html

Been down this road before...


----------



## asota (Feb 7, 2011)

chefhow said:


> http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/62466-where-exactly-should-center-located.html
> 
> Been down this road before...


Not sure why this has anything to do with point I'm trying to get across. Did you read what i had to say? PS I do agree 100% with Mic on his discription of center image location


----------



## 8675309 (Jan 8, 2007)

NO!!!

Even if you TA you still need left/right independent eq to center an image correctly. if you have an active setup you need left/right eq on each channel to fix everything. It may sound centered but if you go through test tones say 80hz-20khz and listen; see where your image is at on each tone on your dash. You will see why it is not possible to achieve a true center with just TA. Even with a full range you would still need left/right eq to fix all issues. 

Also as far as a car the center IMO should be a tad left of center on the driver. That should help with depth. I can sit in a car and imagine the center in the center. But if I listen I can tell a car that is center dash is a right of center.


----------



## asota (Feb 7, 2011)

8675309 said:


> NO!!!
> 
> Even if you TA you still need left/right independent eq to center an image correctly. if you have an active setup you need left/right eq on each channel to fix everything. It may sound centered but if you go through test tones say 80hz-20khz and listen; see where your image is at on each tone on your dash and you will see why it is not possible to achieve a true center with just TA. Even with a full range you would still need left/right eq to fix all issues.
> 
> Also as far as a car the center IMO should be a tad left of center on the driver. That should help with depth. I can sit in a car and imagine the center in the center. But if I listen I can tell a car that is center dash is a right of center.


I agree 100%


----------



## jimmy2345 (Jul 12, 2010)

I don't like T/A. However, even with truly great placement and tuning to get the center without T/A; the center will still shift when you move your head one way or the other.

You stated that this is a characteristic of T/A. It isn't.


----------



## asota (Feb 7, 2011)

jimmy2345 said:


> I don't like T/A. However, even with truly great placement and tuning to get the center without T/A; the center will still shift when you move your head one way or the other.
> 
> You stated that this is a characteristic of T/A. It isn't.


Must be some thing wrong with my system then I have no TA at all and I can slide from drivers seat all the way to pass seat and center image never moves from dead center. Only TA cars that can do that have a center speaker and very well tuned and placed main speakers.


----------



## 8675309 (Jan 8, 2007)

I have never heard a center channel car that sounded worth a ****!! Centered good but no width and no depth! I have only heard one car that did left right with no problem and that was Chris Pates car!!! It was a center one seat car!

By the way what kind of car do you have and what setup do you have. I am sure you would float some boats in the SQ competitor area!

No pun intended



asota said:


> Must be some thing wrong with my system then I have no TA at all and I can slide from drivers seat all the way to pass seat and center image never moves from dead center. Only TA cars that can do that have a center speaker and very well tuned and placed main speakers.


----------



## asota (Feb 7, 2011)

Back in the day I had a system with a center channel (no TA) and you are right it never did sound right. Now days I'm running all old skool US PPI German MB Quart Drx 9255 Audio Control EQX. Running mids and tweets in kicks QSD mid bass in doors. Second set of tweets on a-pilers with 10 ohm resisters on them. Left mids and tweets running out of phase. mid bass and sub all running in phase. Lot of EQ tweaking in the 100hz - 300hz to get it right. Does have a few issues manly the tweets. My health makes it hard for me to get out as often as I would like to


----------



## jimmy2345 (Jul 12, 2010)

asota said:


> Must be some thing wrong with my system then I have no TA at all and I can slide from drivers seat all the way to pass seat and center image never moves from dead center. Only TA cars that can do that have a center speaker and very well tuned and placed main speakers.


There is no way buddy and I call BS!!

When you move, you are moving away or towards a driver which is going to change what you hear and your brains perception of the sound. There is no way around it.


----------



## 8675309 (Jan 8, 2007)

Biggs once told me that all your crap needs to be in phase! If it sounds like a tin can then it is a tin can! 

If you can be in phase and tune! and you can! You will have something to talk about!

I can pick out of phase speakers quick!

I will never tune anything I have with something out of phase. I was sold that you could tune and play with phase. But after many months of tuning and everything in phase I understand what Biggs was talking about!

I figured Biggs knew but when Todd Crowder, Doug winker, and Nick Wingate confirmed it I was sold and it has done me good!!


----------



## 8675309 (Jan 8, 2007)

By the way if you put one side completely out of phase it does make a difference but it does not give you a true stereo!


----------



## asota (Feb 7, 2011)

It will be a goal I work on Doc has me on some new meds seem to be helping getting rid of the a-piller tweets will be another goal helps stage width and keeps image at same height but my $.02 worth tweeters without TA don't sound right up there even with 10 ohm resisters on them.


----------



## 8675309 (Jan 8, 2007)

Dont git rid of the high tweeters!

Don't let us talk you out of good sound!!!!! The bottom line is if you like it; that is all that matters!!

But always be open minded



asota said:


> It will be a goal I work on Doc has me on some new meds seem to be helping getting rid of the a-piller tweets will be another goal helps stage width and keeps image at same height but my $.02 worth tweeters without TA don't sound right up there even with 10 ohm resisters on them.


----------



## asota (Feb 7, 2011)

What do you think if I try some soft domes up there and experiment with resisters again


----------



## 8675309 (Jan 8, 2007)

Tweet up high and no tweet down low then stick with 4-5k in the apillar and 4-5k in the kick. Play with that and see what you get. It may or may not work! But that is part of the car audio!




asota said:


> What do you think if I try some soft domes up there and experiment with resisters again


----------



## 8675309 (Jan 8, 2007)

midbass that can play high is the key. hybrid, hertz, and some others can do so!


----------



## asota (Feb 7, 2011)

Have no problems at all with midbass and sub blend high in stage my midbass and subs always score 8.5 -9.5


----------



## jimmy2345 (Jul 12, 2010)

asota said:


> It will be a goal I work on Doc has me on some new meds seem to be helping getting rid of the a-piller tweets will be another goal helps stage width and keeps image at same height but my $.02 worth tweeters without TA don't sound right up there even with 10 ohm resisters on them.


English please?


----------



## upgrayedd (Apr 19, 2011)

asota said:


> It will be a goal I work on Doc has me on some new meds seem to be helping getting rid of the a-piller tweets will be another goal helps stage width and keeps image at same height but my $.02 worth tweeters without TA don't sound right up there even with 10 ohm resisters on them.


Got punctuation? 

You provide good info but I need a decoder ring to find it.


----------



## AKheathen (Sep 10, 2011)

i think that t/a is overly emphasized as the factor of centering the sound image. and IMHO, the center image should be closer to your head, than the dash-board, unless it is a multimedia system where you are watching movies, in which case, you should have a center speaker imaging the center channel at the screen, lol, but not for sole audio use. long before t/a was readily available in mobile mainstream systems, i simply imaged with db bias and speaker placement/aiming, and the image moved accordingly just fine. try it- have someone move the volume, if you have a mid amp, or adjust the l/r balance on the head, and hear the stage center move side to side. same goes with f/r to get the sound centered at your head. simplest way to get a more even stage across the front seat, whether you are l/r/mid position is to aim the center direction of the right speaker right at the left occupants head, and the left at the right. say start on the left side.- with an even bias, you should be more in line with the main output of the rt. speaker, though further away, and to the side of the main output of the left. as you move closer to the right side, you will be moving further way from the center of the right speaker, so it's db drops, and at the same time entering the path of the left speaker by the time you reach the rt. position, giving again an even bias. it's not an exact set science, and you can also use reflection, like the windshield to adjust, especially to increase stage height, but you get the picture. where t/a is great, and intended to be used, is to give a single point a more uniformed sound image at a single location, which will provide a higher quality, more life-like sound. i have, however been using t/a for more than a decade in home theater use, as it is nearly invaluable in that application, given the way i usually place the speakers, which is almost never even spacing and location. not having it set there really shows up with detectable echo/hall sound. oh, and i assumed it was already well known, but imaging/sound really scrifices if you place the tweeters and mids on different planes. one thing i like about coaxials, is that they place the sound from both drivers from the same exact location. at the least, i like the mid/tweet in the same spot and close as possible to the mid-bass in a 3-way, and try to opt for smaller mids in front for better placement options in 2-way...in more ideal installs. honestly, i really liked the location that gm used in the 80's for the front stage, firing up at the windshield corners. a little aiming, and you are doing pretty good....


----------



## subwoofery (Nov 9, 2008)

AKheathen said:


> i think that t/a is overly emphasized as the factor of centering the sound image. *#1 "*and IMHO, the center image should be closer to your head, than the dash-board, unless it is a multimedia system where you are watching movies, in which case, you should have a center speaker imaging the center channel at the screen, lol, but not for sole audio use.*"* *#2 "*long before t/a was readily available in mobile mainstream systems, i simply imaged with db bias and speaker placement/aiming, and the image moved accordingly just fine. try it- have someone move the volume, if you have a mid amp, or adjust the l/r balance on the head, and hear the stage center move side to side. same goes with f/r to get the sound centered at your head.*"* simplest way to get a more even stage across the front seat, whether you are l/r/mid position is to aim the center direction of the right speaker right at the left occupants head, and the left at the right. say start on the left side.- with an even bias, you should be more in line with the main output of the rt. speaker, though further away, and to the side of the main output of the left. as you move closer to the right side, you will be moving further way from the center of the right speaker, so it's db drops, and at the same time entering the path of the left speaker by the time you reach the rt. position, giving again an even bias. it's not an exact set science, and you can also use reflection, like the windshield to adjust, especially to increase stage height, but you get the picture. *#3 "*where t/a is great, and intended to be used, is to give a single point a more uniformed sound image at a single location, which will provide a higher quality, more life-like sound.*"* i have, however been using t/a for more than a decade in home theater use, as it is nearly invaluable in that application, given the way i usually place the speakers, which is almost never even spacing and location. not having it set there really shows up with detectable echo/hall sound. oh, and i assumed it was already well known, but imaging/sound really scrifices if you place the tweeters and mids on different planes. one thing i like about coaxials, is that they place the sound from both drivers from the same exact location. at the least, i like the mid/tweet in the same spot and close as possible to the mid-bass in a 3-way, and try to opt for smaller mids in front for better placement options in 2-way...in more ideal installs. honestly, i really liked the location that gm used in the 80's for the front stage, firing up at the windshield corners. a little aiming, and you are doing pretty good....


Quoting only a few sentences, others are only subject to vehicle acoustics meaning what you suggest won't always work for someone else's car... 
*#1* Before I start with my explanation, you need to define 1 thing: your Left and Right stage boundaries... 

() are the pillars 
(L------------------------------------R) 
In the ^ above example, where should the center stage (C) be? For music or movie or anything really... Please note I did not include the listener yet. 
1/ (L------------------C------------------R) or 
2/ (L---------C---------------------------R) or
3/ (L---------------------------C---------R)
*Your answer:* ............................................. 


Now, second question: () are still the pillars and @ is the listener 
(L------------------------------------R) 
[email protected] 
In the ^ above example, where should the center stage (C) be? 
1/ (L------------------C------------------R) or 
2/ (L---------C---------------------------R) or
3/ (L---------------------------C---------R)
*Your answer:* ............................................. 


Third question: () are the pillars 
L--(------------------------------------)--R 
In the ^ above example, where should the center stage (C) be? Please note that the L and R boundaries are outside the pillars and that there's no listener... 
1/ L--(------------------C------------------)--R or 
2/ L--(---------C---------------------------)--R or
3/ L--(---------------------------C---------)--R
*Your answer:* ............................................. 


Fourth question: () are the pillars and @ is the listener 
L--(------------------------------------)--R 
[email protected] 
In the ^ above example, where should the center stage (C) be? Please also note that the L and R boundaries are outside the pillars. 
1/ L--(------------------C------------------)--R or 
2/ L--(---------C---------------------------)--R or
3/ L--(---------------------------C---------)--R
*Your answer:* ............................................. 


At last, fifth question: () are the pillars and @ is the listener 
L--(------------------------------------)--R 
[email protected] 
In the ^ above example, where should the center stage (C) be? Please also note that the L and R boundaries are outside the pillars. 
1/ L--(------------------C------------------)--R or 
2/ L--(---------C---------------------------)--R or
3/ L--(---------------------------C---------)--R
*Your answer:* ............................................. 

To answer you really need to focus on your L and R stage boundaries... The outcome is really pretty straight forward. 

*Verdict: *
If you did not choose answer 1/ for each question, then you did not define your boundaries correctly. 

If you really wanted to have your center stage in front of you, you only have 2 options: 
1/ (L---------C---------R........................) 
[email protected] 
2/ L-----------(---------C--------------------R)
[email protected] 
I can tell you that 2/ has never been achieved coz you need your L stage to be more than 2 feet outside the pillars *AND* still keep your R stage inside the pillars - increasing your R stage width only makes your mirror L stage wider too... 

Now, it's all about preference... Some people don't mind having a squashed L stage and prefer their C stage to be right in front of them. 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/62466-where-exactly-should-center-located.html 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/37006-center-image.html 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/27669-alright-then-quick-question-about-what-center-image-means-you.html 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/13063-ok-so-heres-silly-question-about-staging.html
Hope that helps... BOUNDARIES BOUNDARIES BOUNDARIES 


*#2* Your explanation is only half right and here's why: Sound localization - Wikipedia, the free encyclopedia 


> Evaluation for low frequencies
> 
> For frequencies below 800 Hz, the dimensions of the head (ear distance 21.5 cm, corresponding to an interaural time delay of 625 µs), are smaller than the half wavelength of the sound waves. So the auditory system can determine phase delays between both ears without confusion. Interaural level differences are very low in this frequency range, especially below about 200 Hz, so a precise evaluation of the input direction is nearly impossible on the basis of level differences alone. As the frequency drops below 80 Hz it becomes difficult or impossible to use either time difference or level difference to determine a sound's lateral source, because the phase difference between the ears becomes too small for a directional evaluation.


Meaning the balance knob (unless push all the way to one side) won't do much for midbass freqs - meaning if you lower your R side level to have your soundstage in front of you, your center stage will wander from L to R coz a male vocal singing low content will sound in the center of the dash and when that same male sings high notes they will move closer to your side creating a big image. 
Yes you can put freqs under 800Hz right in front of you with T/A which adjust phase but you have to remember that T/A alters phase just like a Xover slope. Therefore putting content below 800Hz in front of you will create nulls and peaks coz the soundwaves *WILL NOT* be arriving at the same time at your ears. 

*#3* Half correct again, if you go full on T/A for 1-seat listening, your suggestion is right. However for those that tune for 2-seat listening/judging, they can still use T/A to put drivers from 1 side in phase (midbass in phase with the midrange and in phase with the tweeter) - whereas 1-seat tune the same + driver pairs (both midbass in phase with each other) 


Kelvin


----------



## sqnut (Dec 24, 2009)

This is how I have it right now.

L--(----------C----------)--R


This is how I would like it

L----(--------C-----------)----R
.....................'@'

Really liked your post Kelvin. 

Arun


----------



## s4turn (Jun 17, 2009)

very interesting thread, just wondering if I adjust the EQ bands for each side to center the image? 
this is obviously from the drivers seat? i.e. it wont sound very good from the passenger seat?


----------



## minbari (Mar 3, 2011)

I am not reading all that, so sorry if this has been said already.

there is nothing an EQ and balance knob can do to push the timing of the sound to one side of the other. T/A is gonna be the high tech solution.

that said, you can still get good imaging and staging without it. people in the 90's did it without T/A.


----------



## sqshoestring (Jun 19, 2007)

Lol...some of us ran rears to make the left more to the left. 


:inout:


----------



## listening (Mar 30, 2013)

Don't need it but it helps=-)


----------

