RMC 1 and Multiple Rear REL Subs

[sep297]

I have just changed my main speakers from standmount Piega Coax 311 backed by two REL S5 subs (connected at both High level and LFE individually to my RMC-1) beside each speaker to very large Piega MLS 2 speakers which are capable of going as low as the subs.

In the past I have had either simple single 'Centre' subs or a stereo pair supporting the main L/R speakers. However, I am now looking to redeploy my REL's towards the back of my listening area, a strange open plan room, as there is now limited space next to the bigger speakers. This will require approx 10 m cables (decided to stick with cables rather than more boxes with Long Bow Wireless) and they will be approximately 3m on one side from the main listening position and about 6 m on the other side.

So if I set my L/R speakers to large the bass will go to main speakers and the high level input will mean I can tune probably a little bit of bass support from the REL's to fill the room. then the processor Sub Outs to the REL's for LFE. 

My main concern is am I getting into the Realms of needing a MiniDSP to bring it together or is it still feasibly within the Dirac control of the RMC-1 and Dirac. I have had problems with the elevated bass in the past. I got round the elevated bass by reducing the Boost on my chosen Harmon curve, manual tweaking of the REL's in terms of the LFE/High Level mix and when the windows rattle the loudness button.

Any thoughts are welcome as moving this lot around is not the easiest task and my experience with having to tune subs is reasonably limited.


Many Thanks


Stuart

[KeithL]

You may have to take phasing with the subs into consideration.

At 50 Hz one wavelength is about 20 feet...
And, at 20 Hz, a wavelength is about 50 feet...

And, if the distance between two subs and the listening position is HOLF OF THE WAVELENGTH...
Then they are out of phase, relative to each other, at that position...

Unfortunately, in real world situations, the math doesn't tell the whole story...
(Which is a nice way of saying that nothing is going to tell you the best placement and adjustments for each until you try it.)
But it DOES mean that, with several subs that are widely separated, you may have to do a bit more experimentation to get them all to work well together.

Oct 17, 2022 11:55:20 GMT -5 sep297 said:

I have just changed my main speakers from standmount Piega Coax 311 backed by two REL S5 subs (connected at both High level and LFE individually to my RMC-1) beside each speaker to very large Piega MLS 2 speakers which are capable of going as low as the subs.

In the past I have had either simple single 'Centre' subs or a stereo pair supporting the main L/R speakers. However, I am now looking to redeploy my REL's towards the back of my listening area, a strange open plan room, as there is now limited space next to the bigger speakers. This will require approx 10 m cables (decided to stick with cables rather than more boxes with Long Bow Wireless) and they will be approximately 3m on one side from the main listening position and about 6 m on the other side.

So if I set my L/R speakers to large the bass will go to main speakers and the high level input will mean I can tune probably a little bit of bass support from the REL's to fill the room. then the processor Sub Outs to the REL's for LFE. 

My main concern is am I getting into the Realms of needing a MiniDSP to bring it together or is it still feasibly within the Dirac control of the RMC-1 and Dirac. I have had problems with the elevated bass in the past. I got round the elevated bass by reducing the Boost on my chosen Harmon curve, manual tweaking of the REL's in terms of the LFE/High Level mix and when the windows rattle the loudness button.

Any thoughts are welcome as moving this lot around is not the easiest task and my experience with having to tune subs is reasonably limited.


Many Thanks


Stuart

[ttocs]

Oct 17, 2022 11:55:20 GMT -5 sep297 said:

So if I set my L/R speakers to large the bass will go to main speakers and the high level input will mean I can tune probably a little bit of bass support from the REL's to fill the room. then the processor Sub Outs to the REL's for LFE. 

I'm not certain I'm understanding this yet. Might need to clarify please.
Setting up the Fronts as Large will send the full range signal to the Fronts, no subwoofers involved.

Next, if you are only using the Center Sub Output setup as LFE and there is no subwoofer setup as Mono, then BM (Bass Management) will send the bass below the crossovers for any Small Channels to the Large Fronts.

If the Rel subs will be at the rear of the room, then using the speaker level connections is going to be a huge issue to tune. The speaker level connection method is best served when the subs are adjacent to the speakers to which they are connected.

BUT, and as Pee Wee Herman famously said, "Everybody's got a big but", with a miniDSP you can use the rear subs to "help" the Fronts. I've done this. It required a Y Cable to split the full range signal for the Fronts with one segment going to the Fronts, and the other segment going to a miniDSP and rear sub(s). I was able to reduce a large null between 60-70Hz created when both fronts were playing bass together.

Oct 17, 2022 11:55:20 GMT -5 sep297 said:

My main concern is am I getting into the Realms of needing a MiniDSP to bring it together or is it still feasibly within the Dirac control of the RMC-1 and Dirac. I have had problems with the elevated bass in the past. I got round the elevated bass by reducing the Boost on my chosen Harmon curve, manual tweaking of the REL's in terms of the LFE/High Level mix and when the windows rattle the loudness button.

As I stated above I believe you would be in miniDSP territory. But I'll need some confirmation for if I have your scenario correct, which I'm kinda guessing at for the moment.

Also, please be aware that when using Large Fronts for BM, the BM will be elevated about +3dB. I'm not certain if or when this might be dealt with in future firmwares (I'm not hopeful), but this is something you want to consider. I am a big fan of using Large Fronts for BM, but I stopped because of this elevated BM issue.

But, I'm currently working on a couple scenarios for BM in my system. For a couple years I had my system setup as follows:
Large Fronts, 2-Stack subwoofers for each Front connected via speaker connection (2 subs for each front), a 2-Stack of subs at the rear of the room connected via miniDSP-2 from a Y cable with the full range signal for each front. Plus, the Left Sub Output was setup as Mono and sent to miniDSP-1:Input-1 then out to all three subwoofer stacks' bottom subwoofer. The Center Sub Output was setup as LFE and sent to miniDSP-1:Input-2 then out to the bottom sub of the three sub stacks. This worked very, very, well.

Because of some things I was doing in the house I had to move some of the system around, so when I began putting it back together I decided to take this time to try some things, just for fun, and I'll use whichever method I like the best - which is looking like it might be as described above. My tinkering is a work in progress so there's nothing for me to suggest yet, but in the next few weeks I'll know a lot more. But the short story is that I'm going to try using the Fronts setup as Small with a low crossover point and the front subs where they work the best in the room vs just being next to each front speaker, along with the rear subs where they are (which is the best spot for them in the rear of the room). miniDSP still needs to be involved for the best tuning and still connected to the processor the same way, Left Sub Mono, Center Sub LFE. For music, the initial tests are not promising vs the speaker level connection method described above.

[sep297]

Thanks Keith and Ttocs for the help,

To give some further explanation the Rels have two inputs the Hi level which is fed off the speaker terminals of the amplifier which blends in with stereo music when set up correctly. Then there is another input for LFE which is typically connected to a processor, I used the left and right sub, and the speakers set to large so they receive the bass for the hi-level speaker terminal input. There is a low-level pre amp input also for the subs which combine LFE and Hi level. I did have bass issues with later firmware but came up with a recipe that was OK 80% of the time.

I now have some big speakers Front L/R I was at first looking to pull the subs to the back of the room (as I no longer have space by the Front L/R for a sub) and probably turn down the amount of bass on the hi-level inputs as the main speakers do not really need bass support and then continue with the inputs from the processor as LFE input on the subs.

My thoughts now, after reading your responses, are to simplify a bit and forget the hi-level input as my speakers don't need it (trying to do it will also introduce a lot of tinkering and wires to the single path of the mains). Then get a miniDSP to align the two rear subs and feed either the low-level or LFE inputs connected via a Y cable from the centre Sub. Then Dirac the system as a whole. I may then later see if the hi-level input direct from the amp is of benefit - just to tinker.

Do I need to integrate the main speakers as well through the MiniDSP if I am only using LFE and not really looking to crossover etc.

As for a MiniDSP I suppose I need a miniDSP 2x4 HD or a new Flex and use the Sub app rather than get a Dirac version MiniDSP.

Now I have simplified my thoughts will the Dirac on the processor be sufficient to feed the subs from the left and right input? rather than a MiniDSP


Many Thanks In Advance


Stuart

[ttocs]

I personally don't feed my Main L&R speakers via miniDSP. I trust miniDSP for the lower frequencies, but I'm not sold on what it might do with the upper frequencies.

And if using a miniDSP fed from the processor, there is no need for a Y cable. The matrix routing in the miniDSP will handle 2 inputs and 4 outputs. It's very versatile and has some adjustments on the inputs and lots of adjustments on each output.

Using a single subwoofer output from the processor going to the miniDSP, and once the subs are aligned, Dirac will see this as a single subwoofer. Since we don't have Dirac's DLBC which will automatically do all the hard work for us, this is the best solution we have. We do the initial alignment and little tweaks, then Dirac does the cleanup work and makes it all pretty.

If I understand your last question, the answer is no. Don't use 2 outputs for the subs, one output to each sub, and expect Dirac to make them work well together. Dirac can correct "each" one well, but Dirac cannot correct "both" to work together. That's what DLBC is for. (Dirac Live Bass Control)

Keeping things simple at the outset is a good approach. As you learn by doing, you will come up with ideas of your own for your situation. It's no harm to try something, even when it fails, because of what you lear along the way.

My room isn't shown in any subwoofer layout or calculator, so I had to try everything myself. I actually spent a couple weeks just moving one subwoofer all over my multipurpose great room. I mapped out the room, did a gazillion REW sweeps, noted which spots were possibles, just by moving the sub a few inches at a time. I learned a great deal about my room. And when I say the sub was moved all over, I mean it was moved into the kitchen area, down the hallway under and around the dining table, everywhere. Consider everything, but don't just read about it and think it won't work, 'ya gotta try it yourself.

[sep297]

Thanks,

My MiniDSP arrived today and I have wired it into the system but have not calibrated anything yet will let you know how I get on.

Cheers

Stuart