Correct. We used a mini DSP mic and ran pink noise through the system. And REW showed a giant dip where the factory applied the all pass. That is generally a good starting point to begin correcting it.how can one tell if their system has these employed? do you need to test & graph phase v.s. frequency plot for each speaker?
If you have a helix dsp with input analyser you can see these by playing left/right channels alone and then summing them and seeing if they sum with 6db or if you have areas with less summation… where there is less summation that’s where your all pass is 👍🏼how can one tell if their system has these employed? do you need to test & graph phase v.s. frequency plot for each speaker?
Correct. We used a mini DSP mic and ran pink noise through the system. And REW showed a giant dip where the factory applied the all pass. That is generally a good starting point to begin correcting it.
I wonder how many folks are out there who have this issue and might not even know it. After it’s corrected is generally when all the gear really shines.
I think he did a few sweeps. Firs the whole system, then speaker by speaker to compare results.i bet the acoustic measurement method is a lot faster
would you play pink noise through one speaker at a time then?
they are easy to deal with in toyota/lexus. Bose systems is where theyre a real *****They are the root of evil for Toyota/Lexus owners. And I'm sure other manufactures as well. From my minimal understanding, they add these filters to help promote a two seat tune environment. So both driver and passenger can enjoy the stock crappyness. Additionally, the actual filter variations vary depending on the vehicle and it's size.
Look to remedy this prior to any gear searching or buying. How will you capture, isolate, and resolve in a dsp. Or the best route if possible just do away with the stock head unit.
if you like, feel free to pm me we can discuss in depth. Right or wrong I can only share my experience and what I saw after the REW sweep. And I know for a fact we saw a massive dip at certain frequencies. Hence adding the all pass to the DSP to present a flatter output.ok, i'm going to stop asking questions here, i'll try to read up on those other threads & get more knowledgeable.
i was trying to ask how to check if all-pass filters are used in your oem vehicle sound system. 🤷♂️
i don't follow people comments on the measuring for all pass filters acoustically, some comments seems contradictory. but again, i am not knowledgeable , so what do i know.
if they are just phase adjustments, you should be able to measure phase electrically, not acoustically and plot phase out for each speaker.
this would take some doing, but should work i would imagine.