Using sub as separate speaker

[Ofer]

As I have been playing with AL there is a challenge (one among many) that is yet to have mastered.
My speakers actualy go lower then the sub. The sub is an 18" PA sub with high spl in the range of 35-120hz. The speakers reach about 25hz. See measurements. In miniDSP it was possible to highpass and lowpass the sub and it boosted the sound nicely. AL works differently. Using wide xo filter of 3 or 4octave on the sub I get good results in std 2.1 configurations. Yet when I try to add the sub as a standalone speaker the correction filter severely attenuates the result way below the target. What am I doing wrong?
Speaker setup:



Measurements:


Simulation and target:



Feel free to point out basic mistakes

 

[juicehifi]

I'm afraid Audiolense isn't designed to support this scenario.

If you digitized your crossover, you could perhaps include the subwoofers as the second lowest drivers in your main speaker, and then you would have more design freedom in Audiolense to do what you want to do.

The easiest solution may be to skip the subwoofer alltogether. If your main speakers can hold their own down at 25 Hz, they shouldn't have much problems with the capacity higher up.

 

[Ofer]

What you are suggesting would probably work with 2 subwoofers. I think Mitch did it in his subwoofer integration walk through. For one sub how would that go? The sub adds a lop of power to the lower end, I don't want to give up on it. Thanks for your answer though. I guess I will stay with long filters on the low end.

 

[Omid]

What you are suggesting would probably work with 2 subwoofers. I think Mitch did it in his subwoofer integration walk through. For one sub how would that go? The sub adds a lop of power to the lower end, I don't want to give up on it. Thanks for your answer though. I guess I will stay with long filters on the low end.

A lot of Subs have R+L inputs (they are summed inside the sub) . Does your sub only have 1 single input? Sorry I can't remember the specifics of your system, perhaps that's not an option...

If you have time, try running a distortion analysis for your mains and your sub (no DSP) in REW. You can either do that through a normal sweep, or better through the RTA window with stepped sine testing. You may find that that although your mains can play down to 25Hz their distortion may be much higher than the sub's distortion below a certain frequency, and your sub may not play distortion free above a certain frequency. If that turns out to be the case, having a broad overlap may not be in your best interest anyway. Just a thought.

 

[Ofer]

Thanks Omid. Currently after swaping the umik1 to an sonarworks xlr mic I am having trouble using REW. It needs to looback or something through the RME and then to the JR convolver. It is beyond me at the moment. My sub is an OEM PA sub in has only one input.

 

[Omid]

Sorry it's so much trouble to sort it out. It'll be worth it in the end !

BTW the RME FF400 seems to allow mixing channels to mono (I don't have one and only looked rapidly at the manual, so I might be wrong). see attached mid page under 'mono'. If I 'm right you can send R+L low freq to your sub via one single output...

 

[Ofer]

Hi @Omid,
Well your suggestion was a good one. What I did eventually is create a 4way speaker in a 2.0 channel configuration. Then in the measurement window changed the channel routing. Enameled overlap on drivers. Don't mind the 4 octave slope I fixed that.

Then ran through all the filter generation protocol.

As you see it is summed nicely without a lot of attenuation.
It sounds great. I have the pronounced bass that the sub produces. In my opinion it sounds better then a long, 4 octave, slope on the sub/woofer.

 

[Omid]

Hi @Omid,
Well your suggestion was a good one. What I did eventually is create a 4way speaker in a 2.0 channel configuration. Then in the measurement window changed the channel routing. Enameled overlap on drivers. Don't mind the 4 octave slope I fixed that.
View attachment 54786
Then ran through all the filter generation protocol.
View attachment 54787
As you see it is summed nicely without a lot of attenuation.
It sounds great. I have the pronounced bass that the sub produces. In my opinion it sounds better then a long, 4 octave, slope on the sub/woofer.

Awesome news!
See, I told you it’d be worth it !

 

[Ofer]

Step response is also better. This is with 2.1 configuration. The sub has a life of its own.

This is with the summed configuration, not perfect but pretty good. Both with default TTD settings.

 

[kevinzoe]

Ofer - I use Audiolense like you do to add my subs as separate left and right speakers so to speak. Have you tried playing with the "Measuremnent & Correction Window" and "True Time Domain Subwindow" lengths within the "Correction Procedure Designer" to improve the IR chart? Might be worth a try . . .

 

[kevinzoe]

opps my bad - pressed return a few times by accident - sorry folks.

 

[Ofer]

Well I did try to increase the TTD window but it didn't improve things on the conterary. I do intend to play with it somemore over the next few weeks. Still trying to find the logic in it.

 

[kevinzoe]

As you try different windowed settings remember that the upper window must be 2-3ms longer than the TTD window settings. For example the "Measurement and Correction Window" might be 9ms while the "True Time Domain Subwindow" would be 7ms or 6ms.
My settings currently are:
Measurement and Correction Window
10hz 9ms
24,000hz 9ms

TTD Subwindow
10hz 7ms
24,000hz 3ms