Article: Integrating Subwoofers with Stereo Mains using Audiolense

[nefilim]

hi @mitchco - thanks again for all your contributions. i'm trying to monkey-see monkey-do but not faring too well

 

i'm quite uncertain about my phase results - i made a few a short video to show where i'm at below.

 

donny is out of his element here but that looks quite awful to me and quite unlike the results you got, is that a huge amount of pre ringing or am i misunderstanding? 

 

i'm using the default TTD filter procedure as shown below but if i were to play with a custom procedure, i'm unclear how to adjust the windows based on the measured phase response, i'm wondering how you made the decision in your first article:

 

"First, let’s try a shorter time correction window in the bass, so now I have 2 cycle window both in the low and high frequencies as entered in the True Time Domain Subwindow:"

 

is there something in the measured data that can guide one on how to adjust the time windows? especially since i have huge peaks from the L sub in the phase response as far out as 45ms and 67ms! i do see in the simulated response that those peaks have disappeared... so that appears to be a good sign at least?

 

 

just to add a little bit of background:

 

• my room is similar to yours, i'm against the long wall left of the center, on the right rear it opens up to the kitchen
• 2 x Kef (semi) full range speakers driven by a power amp (channels 1 & 2)
• 2 + 1 x JL Audio subwoofers
  • right channel is two cascaded subs, both should be receiving the same signal (channel 3),
  • left channel is a single sub (left of the center of the room) (channel 4)
    • anywhere here is just terrible, both in freq response and phase response - i really want to find a reasonable location for the left sub somewhere here but it just haven't been able to yet
• RME ADI2-Pro in multichannel USB mode, channels 1/2 goes to power amp L/R and channels 3/4 goes to 3 subs
• i've manually adjusted the phase knob on the left sub which is closer to the seating area so that the first peaks of the sub impulses lines up (they go out of phase later...) - i'm sure AudioLense can correct for that but figured might as well since these subs (and speakers) are used in a home theater system too (Audyssey isn't the best:) 

 

here's my speaker setup, i've gone quite a different way than you have (since the mains have integrated crossovers - unfortunately). coincidentally, going this way i have noticed i cannot enter a low pass value on the third tab for the subs, i believe AudioLense just uses the high pass value for the mains as low pass for the subs (judging by the XO graphs), i would have liked to play with them overlapping a bit more. 

 

thank you!!

peter

 

[nefilim]

oh also, wondered what does the measured impulse response say about the polarity of the mains vs subs and if that's a problem?

[nefilim]

Thanks so much @mitchco - played around a fair bit and found the default TTD filtering works best for me, as far as I can tell at least, I'll share another video soon :)