Mixing VBSS with Ultimax subwoofers. Need help on integration / DSP - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 7 Old 12-10-2018, 01:01 PM - Thread Starter
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Mixing VBSS with Ultimax subwoofers. Need help on integration / DSP

Hi,
this question has been bothering me for a while now.

Lets assume these are the speakers/subs for a home theater with size 27 x 12.
  • LCR : titans.
  • four UM18 sealed subs with two iNuke6000DSP for each pair.
  • another iNuke3000DSP driving four VBSS.

How do you integrate these subs together? I would like VBSS to take 40-80 Hz range and UM18s take anything less than 40Hz.
How do you EQ all subs together ? after taking a combined frequency response for all subwoofers in the room do you apply PEQ values provided by REW to all three iNukes ? Or do you EQ VBSS and UM18s separately ?


What is the best way to integrate these so that VBSS take upper frequencies and UM18s lower. Or is it a wrong idea to mix VBSS with UM18s ? I have not built any VBSS yet.

Thanks
Manu
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post #2 of 7 Old 12-10-2018, 01:21 PM
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Might want to try posting in this forum: https://www.avsforum.com/forum/113-s...eferences.html. Very good guys over there with lots of info.

But it is a good question. I have pondered a similar question....whereas you would use a miniDSP to eq each sub independently, and then use another miniDSP to eq them together. We may be overthinking it though. I think conventional wisdom is to let Audyssey or other room correction handle the final eq, but when more than two subs are used, there are many paths to get there.
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post #3 of 7 Old 12-10-2018, 02:26 PM
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take the sub out and send it to the inukes.

add:

on inuke 1 (sealed um's):

low pass the um18's at 4th order, 24db/oct LR at 40HZ.

on inuke 2:

high pass the PA460 MBM's 2nd order Butterworth 12dB/oct at 40Hz.

the avr will handle the low pass filer for both (but will mostly control the output of the MBMs).
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post #4 of 7 Old 12-10-2018, 06:14 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post
take the sub out and send it to the inukes.

add:

on inuke 1 (sealed um's):

low pass the um18's at 4th order, 24db/oct LR at 40HZ.

on inuke 2:

high pass the PA460 MBM's 2nd order Butterworth 12dB/oct at 40Hz.

the avr will handle the low pass filer for both (but will mostly control the output of the MBMs).
Great! Thanks LTD02 !
I did not think about this setting.
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post #5 of 7 Old 12-12-2018, 10:14 AM
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I'm running both VBSS's (31 Hz tuned) and sealed Ultimaxes nearfield, with sealed SI HT18's up front.

Of all the iterations, what's worked best for both tactile and subjective sound quality has been to steeply cross over between the VBSS's on the high side, and the sealed subs on the low side. I looked hard at the WinISD sims, and settled on 23 Hz L-R 24 for both high and low passes. The steeper slopes definitely worked better. The sealed also get a 20Hz Q=3.4 6dB boost.

All are leveled and delayed to account for distances to MLP. Subs are crossed to mains in the preprocessor at the usual 80Hz Butterworth 12. Having 1899's for mains doesn't hurt, either.

I tried to integrate them all over the entire bass range, using REW and various approaches, but in the end splitting the duties between ULF and low/mid-bass worked (subjectively) the best. Also made the best use of headroom with my particular setup. And no limiters engaged anywhere.

I have severe limitations on sub placement, obviously if you can move yours then that's a whole different ball game. My goal with the nearfields was to drown the modal response with direct response, and maximize tactile. The four SI's are more to squeeze in a little more pressurization than to even out modes.

I know that's a lot of subjective opinion on the results, but it's a pretty easy by-the-numbers approach to try.

Sources/processing: stack of stuff that if it isn't vintage now, it will be soon!
Amps: stacks and stacks of old iron
Main speakers: big DIYSG
Surrounds: Bose graveyard
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Last edited by fill35U; 12-12-2018 at 10:39 AM.
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post #6 of 7 Old 12-19-2018, 09:21 AM - Thread Starter
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Quote:
Originally Posted by fill35U View Post
I'm running both VBSS's (31 Hz tuned) and sealed Ultimaxes nearfield, with sealed SI HT18's up front.

Of all the iterations, what's worked best for both tactile and subjective sound quality has been to steeply cross over between the VBSS's on the high side, and the sealed subs on the low side. I looked hard at the WinISD sims, and settled on 23 Hz L-R 24 for both high and low passes. The steeper slopes definitely worked better. The sealed also get a 20Hz Q=3.4 6dB boost.

All are leveled and delayed to account for distances to MLP. Subs are crossed to mains in the preprocessor at the usual 80Hz Butterworth 12. Having 1899's for mains doesn't hurt, either.

I tried to integrate them all over the entire bass range, using REW and various approaches, but in the end splitting the duties between ULF and low/mid-bass worked (subjectively) the best. Also made the best use of headroom with my particular setup. And no limiters engaged anywhere.

I have severe limitations on sub placement, obviously if you can move yours then that's a whole different ball game. My goal with the nearfields was to drown the modal response with direct response, and maximize tactile. The four SI's are more to squeeze in a little more pressurization than to even out modes.

I know that's a lot of subjective opinion on the results, but it's a pretty easy by-the-numbers approach to try.
Thank you fill35U. very helpful observations.
just curious, did you try ultimax high passed at around 35 or 40 and without low-pass for VBSS with natural roll off ? would that work ?
I know I will have to use a lot of trial and error methods to see what sounds best in my room. thanks for your input.
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post #7 of 7 Old 12-19-2018, 11:25 AM
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my view differs a little

only at say above 60hz should you have integration issues if they have been placed, gain or level matched and delayed properly.

nearfield subs above 60hz can have cancellation issues
i carefully test whether global eq or individual ones in that range are required
you can often find boosting nearfield and reducing one or more farfield sources at a particular range solves large response variations entirely

but the KICKER IS keep all your sources on through the full range
sure throw an odd hpf or lpf on a source where room issues cause a problem easily fixed
but use all sources for best response, max impact, least variation and maximum spl

if this proves too difficult a source has to be moved to a better location -- or even eliminated!
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