DiyMobileAudio.com Car Stereo Forum banner

21 - 26 of 26 Posts

·
Registered
Joined
·
1,728 Posts
I missed your guys replies, sorry. I was measuring each speaker individually and EQ'ing each alone to find my curve and best XO settings to match the acoustic XO im looking for before matching levels. Luckily now that I have gotten the RTA issue figured out things have been coming together quite well! I was also shooting for half whitledge as a base. I usually take a cut out of 2-4k and raise the low end (20-250) a touch over that as my final.
Im running into a new issue now though, I have a large dip at 185hz with both gb60s playing together. Everything is TA and is summing well everywhere but 184-187 hz. When i flip polarity of one speaker the dip fills out as it should, but the rest of the response is canceling, so im assuming its a phase issue due to the car dimensions. Ive never used an All pass filter before since my previous mini-dsps didnt have the option, but from what I understand this would be a prime candidate for an AP filter. Ive tried some fiddling around with one but Im having an issue filling it in without it pulling heavily to the drivers side and also messing up the surrounding response.
Does anyone have any words of wisdom here? Or am I barking up the wrong tree here with the AP filter idea? Thanks guys!
Typically you'll want to use an all pass on one side, but you may need to use different all passes for each side. They also affect basically the entire frequency range above the center frequency, which is what causes your problem.
 

·
Registered
Joined
·
915 Posts
I missed your guys replies, sorry. I was measuring each speaker individually and EQ'ing each alone to find my curve and best XO settings to match the acoustic XO im looking for before matching levels. Luckily now that I have gotten the RTA issue figured out things have been coming together quite well! I was also shooting for half whitledge as a base. I usually take a cut out of 2-4k and raise the low end (20-250) a touch over that as my final.
Im running into a new issue now though, I have a large dip at 185hz with both gb60s playing together. Everything is TA and is summing well everywhere but 184-187 hz. When i flip polarity of one speaker the dip fills out as it should, but the rest of the response is canceling, so im assuming its a phase issue due to the car dimensions. Ive never used an All pass filter before since my previous mini-dsps didnt have the option, but from what I understand this would be a prime candidate for an AP filter. Ive tried some fiddling around with one but Im having an issue filling it in without it pulling heavily to the drivers side and also messing up the surrounding response.
Does anyone have any words of wisdom here? Or am I barking up the wrong tree here with the AP filter idea? Thanks guys!
When I had issues like that, Allpass filters definitely addressed the issue. If you can post a picture of the the dip, I can recommend an allpass filter to try.

Here is a link to a post where I show the dips I had and what allpass filter settings I used to address them:

Allpass filter help
 

·
Registered
Joined
·
22 Posts
Discussion Starter #24
Typically you'll want to use an all pass on one side, but you may need to use different all passes for each side. They also affect basically the entire frequency range above the center frequency, which is what causes your problem.
Is there any specific way than I go about fixing the phase shift above the allpass? By adding another all pass on the other speaker that is above the frequency that is trying to be remedied to attempt to match the phase shift? Or is something that is going to be trial and error with a frequency generator?
 

·
Registered
Joined
·
22 Posts
Discussion Starter #25
When I had issues like that, Allpass filters definitely addressed the issue. If you can post a picture of the the dip, I can recommend an allpass filter to try.

Here is a link to a post where I show the dips I had and what allpass filter settings I used to address them:

Allpass filter help
Here are some measurements as what I have now. Still need some work of course

Left side swept mic

Left swept.PNG




Right side swept mic

Right swept.PNG



Both sides swept mic

Together.PNG
 

·
Registered
Joined
·
1,728 Posts
Is there any specific way than I go about fixing the phase shift above the allpass? By adding another all pass on the other speaker that is above the frequency that is trying to be remedied to attempt to match the phase shift? Or is something that is going to be trial and error with a frequency generator?
Trial and error is the only way I know of, unless you buy some damn expensive software. And I would use music or pink noise.
 
21 - 26 of 26 Posts
Top