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TOPIC: DDRC-88A and multiple subs ?

DDRC-88A and multiple subs ? 3 years 4 months ago #23753

  • marmasotti
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May I ask whether the suggestion to connect all subs to a single channel is mostly related to a practical reason - i.e. in order not to "sacrifice" one ore more valuable Dirac-managed channels) - or rather is any theoretical reason behind.
In fact , during the past months not personally pleased before the idea of using a "dumb" cluster (dumb with respect of a fully grained Dirac processing), I used to dedicate two channels, out of the eight ones of DDRC-88A, to address a proper three-sub set equalization. Those two channels taken out from DDRC-88A were connected to an additional OpenDRC-AN that I eventually own , with no mixed-phase filter, however, and thus sweet spot sensitive. Just experiments .....till a miniDSP 2x4 DL eventually came into the scenes .
Thank you for any criticism.


PS: Let me further explain the composition of my setup:

- Front channels, using one OpenDRC-AN (w/Acourate)
- Center, Side and Rear channels, using five channels out of the DDRC-88A
- 3 subwoofers, using the three remaining inputs available from the DDRC-88A
Last Edit: 3 years 4 months ago by marmasotti.
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DDRC-88A and multiple subs ? 3 years 4 months ago #23785

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@ marmasotti

Interesting setup indeed! The upcoming DDRC-88BM firmware upgrade feature (to be announced soon hopefully if all goes well) will provide that matrixing that you need here. i.e. 1 x Dirac Live filter - > branching out to multiple delay lines to time align the subs.
Now this recommendation (1 dirac live vs 3 dirac live) is most likely because it's best to optimize the multiple speakers as a whole. We've seen that it had a better results before and I seem to recall that it was a recommendation from Dirac Team. Now if you have some data to share for the community on your setup, we'd certainly love to see this since this community is all about sharing. :-) We don't want to limit creativity, multisub placement/tuning/optimization is of great interest to all of us. More data, more ideas, more sharing can only be good! :-)

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DDRC-88A and multiple subs ? 3 years 4 months ago #23796

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Attempting my homebrew solution to extend the number of Dirac Live channels also allowed me not only to get a better meshed approach but also to obtain a handy reference to identify balance of intervention for the additional subwoofers and timbre matching for the center channel, given the purity of a 2-channel minimum phase, that I can ensure as a unique experience in itself.
About recommending 1 dirac live vs 3 dirac live, I think that is mostly due to the limitation that any measurements set refers to a single DDRC88A as a whole, never encompassing more than one device. In fact, supposing to use two Dirac Live systems simultaneously, one would be able to run only through two separate measurement sessions, conveniently trying in each of them to position the microphone in identical ways, but that approach would sound fuzzy and impractical to achieve. Still, I believe that the rational behind the Dirac Live concept would suggest a fully coordinated span across all channels but I probably would never have asked about a 3-DIrac Live system before any minDSP 2x4 DL appeared, that's the reason I played with a hybrid mix of processors. Anyway, it definitely seems to have now cats among the pigeons.... ;-)
In short, my question: will the miniDSP 2x4 DL be managed together with the DDRC88A as a whole system?
Thanks.
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DDRC-88A and multiple subs ? 3 years 4 months ago #23799

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It's more effective to run the subwoofer signal through a single Dirac Live channel. That way, Dirac Live will correct the combined response, which is what you want. If you have a separate Dirac Live channel for each subwoofer, Dirac Live will equalize each subwoofer separately and then when you play audio, those subs will interact and the overall response will no longer be as good.

You can try measuring it for yourself ;)
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Last Edit: 3 years 4 months ago by john.reekie. Reason: Clearification
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DDRC-88A and multiple subs ? 3 years 4 months ago #23805

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I asked myself the same question, that looks like the following:
What is better, ( A ) 2 speaker devices both equalized with 1 measurement sweep in one single DL channel, or ( B ) 2 speaker devices each independently equalized with their own measurement sweeps, each occupying their own dedicated DL channel?

I would tend to prefer answer B, even when, as in connections of subwoofers, the source signal fed would be the same content to all speakers. Even when each source signal fed is different, like in the case for the other non-subwoofer speakers, there is a combination of waves produced - in that case can't stand the need of an individual equalization treatment for each speakers just because their contents is different from each other, just like it can't stand the need of a single catch-all-speakers eq just because the content fed to those speakers (subwoofers) is exactly the same for all of them.
My opinions, and I agree with your suggestion and I'll do some measurements.
Last Edit: 3 years 4 months ago by marmasotti.
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DDRC-88A and multiple subs ? 3 years 4 months ago #23832

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Hi again, I look forward to seeing your results.

Room acoustics are very different at subwoofer frequencies, so there's a different way of thinking about it than for speakers.
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DDRC-88A and multiple subs ? 3 years 4 months ago #23844

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Agreed :)
A further extent that came into my mind in favour of the answer B is the chance to settle more easily in a mixture of different brand/model of subwoofers, that would not otherwise be discriminated in their set. In my view, mixing different subwoofers in the same setup is not wrong practice , as along as you ensure you have individual control of them.
Last Edit: 3 years 4 months ago by marmasotti.
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DDRC-88A and multiple subs ? 3 years 3 weeks ago #25631

  • ps702
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Sorry to resurrect, but I'm also curious in a rather 'outside' use-case of wanting to use the subs slightly differently. I'm not sure if the DDRC-88A is the correct solution to this (or if DL even handles this well ATM) but what I'd like to use it for is having a 5.1 setup but with 3 subs. To explain better - only one LFE channel on a dedicated sub but two other subs working as the bass extension for LR.

My theater is set up with satellites (Focal Bird) which nominally can reach 80Hz but not well and definitely not forcefully. I'm ultimately looking for a DSP solution to allow the front subs (placed directly below the LF&RF satellites) to handle everything from ~100Hz down - essentially making them 'Large' speakers... but avoiding localization issues. Then finally allowing the actual LFE channel from source to be directed to a third sub in a different location.

Not really sure if this is an adventure in futility (or stupidity...) but I can think of very good applications in later builds if it would work. I can envision a fully built theater stage eventually with in wall LCR channels each with a dedicated sub in the 'stage' below each channel... which would allow for lesser speakers to deliver full-range sound for 2.0 sources as well. ;)

I think this may be over/under thinking things but hopefully someone can steer me in a good direction!
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DDRC-88A and multiple subs ? 3 years 3 weeks ago #25633

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ps702 wrote:
looking for a DSP solution to allow the front subs (placed directly below the LF&RF satellites) to handle everything from ~100Hz down - essentially making them 'Large' speakers... but avoiding localization issues. Then finally allowing the actual LFE channel from source to be directed to a third sub in a different location.

The forthcoming DDRC-88BM upgrade would be perfect for that. You can use the two "unused" output channels for the L&R subs and implement a crossover for the L/R subs and mains. That combo will get its own Dirac channel (for each side). LFE is a separate channel.

You've left out the low frequencies from the other channels, but I expect you will be able to route it to either the LFE sub or the L/R subs.
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?
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DDRC-88A and multiple subs ? 3 years 3 weeks ago #25635

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That's great to hear! Yes I'm not really worried about the other channels, as the surrounds and center having slightly rolled lows at the crossover point doesn't really bother me. Being able to maintain a high-WAF environment which provides enjoyable 2 channel listening as well without the askance looks that "a room full of speakers and equipment" causes is my main concern.

I'm looking forward to seeing the details on that DDRC-88BM! Thanks!
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