TOPIC:

OK all:

MiniDSP me through a 13.4 Atmos system (L/C/R, Wide L/R, Height L/R-front and rear overhead-, and L/R Side and L/R Surround Back).
Here's where it gets tricky: I want dedicated subs on the front L/C/R's, as well as the Rear Surround L/R's, plus 4 subs for LFE.

How many 88A's? 2x4's, etc? Assume pre-out inputs from AVR. I need to break out speakers and subs for L/C/R and Surr L/R first, then calibrate, then locate and DSP the 4 LFE subs, then master DSP calibration, correct? OK, let's see the brainpower, because once this is pulled off, it will doubtless lead to a few new products from MiniDSP (saving us ALL tons of heartache and cabling!), plus there will be many more that will out-do this setup once complete.

(FYI: please save the "you don't need that many subs," or "that's too much engineering," or "you could do as much with far less." I'm looking to follow the same conventions as CAT. If you've heard a CAT system calibrated (DSP'd) properly, there is no discussion necessary about the merits- and use- at any sound level from background music to peel-your-skin... of 4 to 100 subs. It's about maximizing the reach of even, smooth, dynamic bass response no matter the listening position without perceptible haptic differences in SPL based upon proximity to a sub. i.e: when you use 2 subs when you need 4-6, and you simply increase SPL, it is ABSOLUTELY detectable when you move close to either one of the two subwoofers. You FEEL the location of the sub because of your proximity to it. This makes the "non-directional" benefits of the sub moot, as they now become directional. With multiple subs, you simply don't feel it at all. It's just smooth and even and fast and tight- everywhere. You've either heard it done right, and you understand, or you haven't and don't... and that's OK.. just please don't knock it until you've actually experienced it yourself, firsthand).

And........GO!

Do I count correctly - 9 subs?

-Bob C.

Assuming you agree that the subwoofers should all be EQed/room-corrected as a single unit, you can use 2 x DDRC-88A and 2 x 2x4. Otherwise, 3 x DDRC-88A.

HTH

Yes Sir!

Sorry; new poster here. Yes, but 5 will be utilized the "bottom octave driver" of the L/C/R and Surround L/R channel speakers.

Hi John:

The subs will be individually EQ'd as follows: L/C/R main and surround L/R subs will be calibrated as the bottom octave driver of each individual speaker. The LFE's will need to be individually calibrated for time-alignment/location, but then, yes, the LFE's will be room-corrected as a single "LFE channel." Is this your understanding/recommendation, as well? Thanks much!

Well I don't quite understand exactly why you designate some subs as "the bottom octave driver of each individual speaker"... if that means that you want to calibrate that sub and the speaker on one Dirac channel, and not use bass management and calibrate the subs with the rest of the LFE subs, then you'd need the 3 x DDRC-88A option.

Probably would be help to draw up some sort of diagram

That is correct. One sub for each of the L/C/R and Surround L/R, then 4 subs for LFE channel (probably 2 subs each on the 2 separate Atmos LFE channel outputs).

In considering your suggestion, it seemed like the DDRC-88A to 2x4HD would give me a two single channels (L/R for example) out of the DDRC-88A, into the 2x4 HD, then one output each for the Left Front speaker and Left Front speaker Sub (calibrated together as the "Left Front Speaker"), and one output each for the Right Front speaker and Right Front speaker sub (also calibrated together as the "Right Front Speaker"). The same for the Center speaker (one channel out of DDRC-88A to 2x4HD) into one input, and one output each for the Center speaker and Center speaker Sub, calibrated as "Center Speaker."

Then the same treatment for the Surround L/R, and then LFE. For LFE, one sub out of the processor to the DDRC-88A, then that channel out of DDRC-88A to one input 2x4HD, then one output each to 2 subs (calibrated as "LFE Left"), and the same config for the right.

I think that makes sense. One last complication, if I may (since you guys solved the primary config easily!).

If I want to use multiple subs for the Center Speaker, for example, could I just use a 2x4HD (input from DDRC-88A center channel output), and then 4 outputs from the 2x4HD (one for center channel speaker and the other three for 3 subwoofers attached to the center channel), then calibrate all four outputs (Center channel speaker and 3 center channel subs as "Center Channel Speaker")?

I hope I'm getting that right...

Thanks very much!!

Brenton9 wrote:

If I want to use multiple subs for the Center Speaker, for example, could I just use a 2x4HD (input from DDRC-88A center channel output), and then 4 outputs from the 2x4HD (one for center channel speaker and the other three for 3 subwoofers attached to the center channel), then calibrate all four outputs (Center channel speaker and 3 center channel subs as "Center Channel Speaker")?

I believe that would work.

However I wonder if you are aware of the capabilities of the DDRC-88BM plugin. Also, there's a DDRC-24 that might even fit into the picture. Depends on whether you are doing bass management or not (you haven't actually said, I don't think).

I definitely would like to utilize both bass management plugin and am completely open to DDRC-24.. that's why I'm reaching out to the experts.. as long as you understand what I'm trying to do, I'm totally open and curious as to how best to get it done.. if you have any questions on my config, please don't hesitate to ask, so I can clairify. If you already have all the info you need to recommend a minidsp configuration and any setup help you can, I would be most appreciative!!
Thanks so much, and I look forward to getting some specific recommendations on implementation!

Well, I think the simple way would be to use 3 x DDRC-88A/BM.

Unit 1. Inputs, L, R, SL, SR. Outputs speaker + sub for each.
Unit 2. Inputs 7 speaker channels. Outputs 7 speakers + lowpassed BM signal for subs (I assume to LFE subs)
Unit 3. Inputs C, 1 more speaker, BM from UNit 2, LFE. Outputs C speakr, one more speaker, that leaves 4 for LFE subs and 2 for center channel subs.

You'd have some work to do manually adjusting the delays between units etc.

Not 100% sure that would work but suggest once more you draw a diagram so you can work through it for yourself...

If you use a single Dirac channel to calibrate the subs, it may be advisable to EQ the individual subwoofer's power response based on their location, i.e. the corner subs will sound different than midwall subs based on the difference between 1/4 space and 1/8 space acoustic environments. Once the subs sound is balanced, then apply global equalization to change the timbre. Remember that the phase response of subwoofers will depend heavily on wall reflections and listener location.

I generally recommend high low pass crossovers near the transition frequency of the room to reduce distortion and power compression in midrange/midbass speakers.

Any updates on the sound? I am designing a system with over 30 channels...

I've started thinking along similar lines: dedicated subs for some (all) of the non-LFE channels. But, then the multi-sub, mono bass mantra enters my brain (and is how I am running things now).

Right now I have BG Radia 520 fronts, BG Radia CC-220dx center, BG Radia PD-6LCRi for the rear and side surrounds. I bass manage all of those channels and mix with LFE and drive two 12" Klipsch (yeah, a real quality mismatch there) subs in mono at the 1/3 and 2/3 positions along the front wall. It works rather well.

But, I was thinking this way: send the LFE to one channel each of the front subs, feedthrough from front L and R to their respective subs on the other channel. I drive the front L and R with a Crown XLS-1502 amp which (a) offers high or low-pass filtering on each channel and (b) a feedhrough of the input signal (literally: a connector wired in parallel with the input) on each channel. Yes, I'd have to low-pass in the sub, attenuate the fed-through signal 10db, and compensate on the LFE channel with a bit of LF lift to compensate for the low-pass activated in the sub, The practical upshot is that I get stereo bass for the front L and R channels, and mono bass from the LFE. (Alternately, I could add dedicated subs for the front L and R channels and keep the current two for LFE in mono). In fact, there are sub plate amps that are designed with separate balanced LFE and L+R inputs, with low-pass filtering on the latter, though I'm not sure if they're designed to be used together at the same time (I think so, since these are touted as HT and music dual use subs).

Center, side, and rear signals could be low-pass filtered, and mixed into the LFE channel.

Alternately, two more subs could be added in the back, in a similar fashion, each taking a feedthrough channel from the Crown XLS-1002 amp driving each pair of speakers (read and side surround), and just mix center bass into LFE.

Does this violate the whole "mono bass" mantra? I get that for the LFE channel, but does it apply for bass directed to the individual channels? After all, in the "old days", we'd strive for full-range speakers capable of reproducing signal from 20 Hz to 20 kHz, and therefore effectively having stereo subs.