Home theatre - multi sub calibration advice.

[Danimacl]

Hi folks,

I am finishing up a theatre renovation and am looking room calibration software and hardware implementation advice.

Feel free to yell at me if I’m not in the right forum.

Sorry if the post is a bit long but I feel like the more specificity the better.
I have a have what many people would consider a smaller home theatre 11’W x 15’L x 7.2’H. As many of us know the smaller the room the trickier the acoustics. I have done everything in my power to acoustically treat the room.

Now here’s the question:
I currently own a Denon x4400H and a Dirac live enabled MiniDSP DDRC-88a with BM.

Now I have multiple custom built subs that all perform best within certain frequency ranges. I’m simplifying the setup for the sake of brevity, I’ll also give you my ideal high and low pass filters.

Subwoofer 1 - built into a rear seating riser. HP 25hz @48db - LP 80hz @24hz

Subwoofer 2 - large front ported sub under screen. HP 18hz 48db - LP 60hz @ 24db

Subwoofer 3 and 4 - mid bass woofers behind acoustically transparent screen. HP 60hz 24db - LP 150HZ @ 24db

And I have smaller LCR speakers which I’d like to high pass higher than normal - 150hz.

Am I better off buying a newer Denon X3800 with Dirac ART and 4 LFE? do all the processing in one unit? Will I be able to set individual high and low pass filters on the subs?

Or

Keep my Denon X4400H and Mini DSP? route all the subs through the mini dsp and have mini dsp Dirac calibrate all of them into one cohesive system 18-150hz. Then run one lfe signal into the mini dsp and use the denon to crossover at 150hz into the mini dsp.

Or

Keep my Denon X4400H and Mini DSP?
Run LCR and all subs through mini dsp and have Dirac calibrate all of that. Then In the denon run LCR as full range with dedicated lfe.

 

[DVDdoug]

REW and a measurement microphone.

And then maybe Multi-Sub Optimizer.

As many of us know the smaller the room the trickier the acoustics.

Most rooms are "small" compared to a concert hall, auditorium, or real theater.

I have done everything in my power to acoustically treat the room.

I always say, "diagnosis before treatment".

 

[Danimacl]

REW and a measurement microphone.

And then maybe Multi-Sub Optimizer.


Most rooms are "small" compared to a concert hall, auditorium, or real theater.


I always say, "diagnosis before treatment".

My apologies Doug, I was writing this on my iPhone and accidentally hit submit on the post before I was finished writing the post. You can now see the edited original post.

 

[DaveBoswell]

If it were me, I would be using REW and MSO to get all the subs working very well together and phase/time aligned, then have this single virtual sub presented to your AVR for final polish using Dirac (not Dirac ART).

Reasoning is that your setup has subs with various port tuning frequencies, different slopes on the HPF and LPFs (which cause varying degrees of phase rotation), and presumably materially different output capabilities and efficiencies at different frequencies. There is a very strong likelihood that you are getting a wide range of phase cancellations and phase summations across the sub woofer frequency range as a result resulting in significant reduction in total output and efficiency along with potential smearing of the response in the time domain.

ART may or may not be able to take this complex setup into account but I would doubt it would do as good a job as REW/MSO and some learning on your part. I think ART or any waveforming technologies works best when the phase response of the speakers being used is the same for all speakers.

If you are game, post your results in the MSO thread and we would be happy to give advice. Check out MSO tutorial video on my sig below to get a flavor of what MSO can do to properly align multi subs in phase, eliminate phase cancellations, and simultaneously provide consistent and smooth response at multiple seating locations. Your setup will be more complex that the 3 sub setup I use as the example.

 

[andyc56]

From reading the first post in this thread, it's not clear to me what the strategy of this system is intended to be. I wrote a post back in 2018 about the technique of operating subs in mutually exclusive frequency bands, noting that this is not the type of system that MSO is intended to optimize. Although MSO is flexible, it's not intended to deal with arbitrarily-chosen configurations, especially in the case of subs operating in mutually exclusive frequency bands.