Balanced Subwoofer and Monitors to a USB DAC

[amazingtazing]

So I picked up the Monolith 15" subwoofer and need some advice on how to connect it in parallel with my JBL LSR monitors and Motu M4.

The sub has three methods of connecting:
A single, mono RCA cable from a LFE/Subwoofer Output into one of the RCA ports on subwoofer.
Connecting 2 RCA cables from a stereo preamp source into both RCA ports on the subwoofer.
Or connecting an XLR cable from a balanced source into the XLR input on the subwoofer.

What do you think is the best method? The subwoofer has an XLR pass-through output port. Currently I have the balanced TRS outputs 1-2 from my Motu hooked up to my monitors. Should I:
Connect one of the balanced outputs to the subwoofer, and then using the pass-through on the subwoofer to connect one of the monitors? The other monitor will be wired directly to the balanced output of the Motu.
OR
Take 2 RCA cables and connect both RCA input ports on the subwoofer to the unbalanced RCA outputs 1-2 on the DAC? The manual said this is the worst method.

Pictures for reference.

 

[Berwhale]

The manual suggests that XLR pass-through is to go to another Monolith Sub, rather than a monitor. See page 12: https://downloads.monoprice.com/files/manuals/24458_Manual_200507.pdf

Why can't you take one of the TRS Line outs (3 or 4) to the XLR input on the Monolith?

 

[amazingtazing]

The manual suggests that XLR pass-through is to go to another Monolith Sub, rather than a monitor. See page 12: https://downloads.monoprice.com/files/manuals/24458_Manual_200507.pdf

Why can't you take one of the TRS Line outs (3 or 4) to the XLR input on the Monolith?

I see, I wonder if there is a reason you shouldn't plug a monitor into that pass through? I'll have to see when I set up the subwoofer.

Those outputs are separate and line out (bypassing the monitor volume knob on the Motu audio interface). Additionally, I can only select 1-2 or 3-4 in Windows. So if I were to plug in the sub on 3-4, I wouldn't be able to listen to my monitors on 1-2.

 

[Berwhale]

The XLR pass-through could be low passed, but the manual doesn't indicate it. This type of issue is why I bought a 'studio' sub, rather than an 'HT' one. My Presonus Sub8 has stereo TRS inputs and outputs, with the ouputs high passed so the low frequencies are not passed on to my little MTM monitors.

 

[ad_fletch]

You might need an outboard DSP to control 3 channels at once.

@mdsimon2 has posted several times on here about using CamillaDSP on an RPi with his Motu M4 for this job. I believe EqualizerAPO can do it too if you want to use windows.

 

[amazingtazing]

You might need an outboard DSP to control 3 channels at once.

@mdsimon2 has posted several times on here about using CamillaDSP on an RPi with his Motu M4 for this job. I believe EqualizerAPO can do it too if you want to use windows.

Thanks for the input. I am going to explore the EqualizerAPO option as I already have it installed.

So right now I have the subwoofer in sealed mode, with RCA Monitor 1-2 Out from the Motu to the subwoofer. Even though it's not recommended to use stereo RCA, I don't really detect any hiss or anything. The balanced monitor out 1-2 are going to my JBL monitors. I have the internal crossover enabled on the subwoofer. It is doing a decent job at cross-overing. It sounds okay but I definitely need some more correction which is where the DSP will help I think.

 

[tetragrammaton]

I have a similar situation (audio interface, studio monitors and HT sub) and simply use a Behringer CX2310 as an external crossover, bypassing the subs LPF.

You really need an HPF to mains to start with proper sub integration, imho. I suggest you look into external crossover options