DiyMobileAudio.com Car Stereo Forum banner
1 - 20 of 42 Posts

·
Registered
Joined
·
336 Posts
Discussion Starter · #1 ·
Any good tips on how to time align a sub woofer?
 

·
Registered
Joined
·
89 Posts
Assuming the sub is the furthest speaker from your listening position, you'll want to time delay everything ELSE, not the sub...
 

·
Registered
Joined
·
336 Posts
Discussion Starter · #3 ·
Yea but I'm having a hard time figuring out by how much because unlike the front stage it's a lot tougher to listen to a setup disc and figure out the best center or front.
 

·
Registered
Joined
·
265 Posts
im watching this closely. want to hear the gurus about this.
 

·
Registered
Joined
·
771 Posts
What kind of deck are you using?

I use a Pioneer 860mp and it helps to do the sub alignment.

But the deck has the toys(but not all of them).
 

·
Registered
Joined
·
287 Posts
1. Measure distance from forehead to all speakers in meters (0.00 accuracy is more than enough).
2. Distance of farthest speaker (usually your sub) - distance of speaker to adjust
3. Divide by 343
4. Multiply by 1000
5. Answer is time delay in milisec
6. Listen and make small adjustments, I tend to delay the fronts/center a bit more (all by the same amount) than the math says to give the illusion of "bass up front." Also helps to have your midbass up front playing as low as possible and sub low passed at 24db/oct below 100hz (I tend to set it no higher than 75Hz).


Hope that helps.
 

·
Premium Member
Joined
·
4,235 Posts
Bass up front depends much more on the response in the transition from bass to midbass and on woofer distortion and rattles than it does on time alignment. Shoot for a smooth transition from 60-160 Hz and between 6 and 9dB more bass than midrange. Then, once the bass sounds more like it comes from up front, adjust the delay for the rest of the front speakers to improve the bass up front illusion. Adjust all of the front speakers by the same increments.

This is difficult to measure acoustically, because high frequencies are helpful in viewing the initial peak in the response. Also, the group delay in the sub's response, which is a function of the response roll-off is also difficult to measure. That's why setting the sub using the tape measure and making final adjustments by ear is the best and quickest way to do this part.
 

·
Registered
Joined
·
7 Posts
You have to calculate a bit, setting up by ears is extremely hard to do.
Anway, consider your crossover setup too. It's better to have even-order filter. They cause only a phase shift of 180° which is easy to manage by reversing the polarity of the speaker or (if available) use the radio or amp. If you have uneven-order filter, like 6dB and 12dB you might need a continuously adjustable phase shift.
 

·
Registered
Joined
·
336 Posts
Discussion Starter · #13 ·
What kind of deck are you using?

I use a Pioneer 860mp and it helps to do the sub alignment.

But the deck has the toys(but not all of them).
Alpine F#1 w/ PXI-H990. It does have auto TA but I never really trust those, I always prefer to do it by ear as much as I can and I usually find better results that way.

Would T/A help you get away w/ a higher LP point, while still keeping the bass up front?
From what I heard, it can definitely put the bass and staging up front and it makes sense. With the subs being so far away and playing at the same time as the result speaker, it's quite a lag behind so the bass notes are not reaching you at the same time but rather later on.

1. Measure distance from forehead to all speakers in meters (0.00 accuracy is more than enough).
2. Distance of farthest speaker (usually your sub) - distance of speaker to adjust
3. Divide by 343
4. Multiply by 1000
5. Answer is time delay in milisec
6. Listen and make small adjustments, I tend to delay the fronts/center a bit more (all by the same amount) than the math says to give the illusion of "bass up front." Also helps to have your midbass up front playing as low as possible and sub low passed at 24db/oct below 100hz (I tend to set it no higher than 75Hz).


Hope that helps.
Awesome thanks! I have my mid-bass playing down to 60 hz which definitely helped. Another tutorial I found was http://www.diymobileaudio.com/forum...-realized-easy-way-calculate-time-delays.html for those interested


I'll play around with it today and post a "what worked for me" based on all the tips above and other links I found. It will most likely be tape measure first for initial and then playing around with different songs to see which ones I can hear a difference in and I think this will be tougher part but I got some songs in mind.
 

·
Registered
Joined
·
336 Posts
Discussion Starter · #14 ·
One other interesting thing to consider is from which point do you measure the subwoofer distance from if the woofer is facing the back of the car?

1) from the cone to driver
2) from the cone to back of trunk, and then from back of trunk to driver

I'm thinking #2 since that's the path that the waves would follow.
 

·
Registered
Joined
·
2,027 Posts
Start with a tape measure. That'll get you close.

Second, you'll want to find useful songs that have a good bass note that incorporates both the mid woofer and sub in the sound. Listen to the song, or a variety of songs even, and pay attention to the bass note. Adjust the TA setting both above and below what you guessed with the tape measure. Try and listen to how the beat syncs between the sub and mids. Also pay attention to dominance. If the mid comes in early, it will have a dominant presence. If the sub comes in early, it tends to become dominant. As they get more correct, neither will overshadow the other.

When you're set correct, both the presence and articulation of note will be synced between the two.

I'll make a side note that I have found it to be easier to try and sync one mid woofer at a time to the sub. Set balance all the way to the right so you only hear the right woofer. Then adjust the woofer TA till it syncs with the sub. Note that your head and ear position will change as you turn your head, so try not to move around all over the place when doing this. You can do the right woofer and sub and then left woofer and sub or you can do the right woofer and sub and then TA the left woofer with the right.

In the end, you should be very close to what the tape measure said initially. You'll really only be a notch or two off at the most. Be wary of reflections. The car's a reflection rich environment, and you can very easily TA in a reflection rather then the original wave if you're not paying attention. This is why I say you will generally be pretty close or dead on with the tape measure. If you aren't, you are most likely TAing a reflection wave and you may want to start over again.

I'll also note that the group delay of the subwoofer (ported designs) will also play a roll in the TA setting. You have the option to tune partially to counter that group delay. It depends on where you have the sub crossed and how much and where the delay is. You'll notice it a little as you TA where you seem to focus towards the higher beat frequency or the lower frequency range as you adjust. You won't get this with sealed setups since the group delay is so minimal, but it can be noticeable in ported applications where the delay is 15, 20, 30ms or more sometimes.
 

·
Registered
Joined
·
265 Posts
Assuming the sub is the furthest speaker from your listening position, you'll want to time delay everything ELSE, not the sub...
One other interesting thing to consider is from which point do you measure the subwoofer distance from if the woofer is facing the back of the car?

1) from the cone to driver
2) from the cone to back of trunk, and then from back of trunk to driver

I'm thinking #2 since that's the path that the waves would follow.

then doesn't it mean that the above 2 statements are totally contrasting each other???
one says delay the sub , and the other says DO NOT.
please explain this in detail :)
 

·
Registered
Joined
·
336 Posts
Discussion Starter · #17 ·
then doesn't it mean that the above 2 statements are totally contrasting each other???
one says delay the sub , and the other says DO NOT.
please explain this in detail :)
How so?

I think everybody agrees that the subs should be part of the T/A. (As mentioned you would use the sub as the 0 mark and delay all other speakers). When people refer to measuring the distance from speaker to your ear it's easily done up front since usually the pathwave is clear to your ear however with a sub if it's facing back of the car the distance traveled is longer than if the sub faces the front of the car so it's a valid test to delay the front speakers based on the distance in two different measurements to see which one works best:

Scenario #1: from sub cone to driver
Scenario #2: from sub to back of car + back of car to driver
 

·
Registered
Joined
·
265 Posts
wait a moment. so you say the sub must be at zero..
then how do the 2 scenarios matter? anyways we are not delaying the subs.
sorry for asking this, i didnt get it..
 

·
Registered
Joined
·
587 Posts
wait a moment. so you say the sub must be at zero..
then how do the 2 scenarios matter? anyways we are not delaying the subs.
sorry for asking this, i didnt get it..
If the sub is your reference, not delayed, the next furthest driver from the listener would be delayed by the difference in path lengths. If your sub is 7 feet from your head, and your right mid-bass is 4 feet from your head, your right mid-bass time delay would be equivalent of 3 feet of time delay, translated to milliseconds. Your left tweeter could be 2 feet away from your head and 5 feet of time delay. That way, the waves from sub travelling 7 feet arrive at the same time as right mid-bass that's 4 feet away and was "held up by 3 feet," and your left tweeter that's 2 feet away and was "help up by 5 feet."
 
1 - 20 of 42 Posts
Top