Adding a subwoofer to a 2.0 system using zone grouping

My current 2.0 system is a Lumin D2 streaming DAC with balanced connections to two PS Audio M700 mono amps. I don’t think there’s any way to integrate a subwoofer into this system without adding a preamp. My plan is to buy a HifiBerry DAC+ and connect it over wi-fi with RCA connections to the sub. Then, group the zones in Roon with master clock priority given to the Lumin since it as to render MQA. Both DACs are Roon Ready with RAAT, so I think they should sync well. As far as I’m concerned, this would create a seamless, perfectly synced system, just like they were both connected to the same preamp. (Added benefit is that I would be able to move the sub anywhere in the room). Would this work? Any suggestions? Thanks!

Don’t know if you’ve bought the sub yet, but REL subs (and others) let you make a high level connection, i.e. from the same binding posts on your amps that your main speakers use.

This is the preferred way to connect powered subs, rather than using a pre-amp, as the sub will then receive the same signal as your main speakers.

With that in mind, your current design seems overly complicated.


I haven’t bought the sub yet. I do remember seeing that the REL interconnect allows a high-level connection to fully differential amps by letting the (-) speaker wire just hang down. Thanks for the suggestion; that seems simpler than the zone grouping!

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Looks like I will have to buy two RELs and connect them like this:

Yes, I think you’re right about that. In fact, the manual for the T/9x specifically says that. That makes for a more expensive solution. Bummer.

I buy a lot from Upscale Audio and they sell RELs. They are good people and knowledgeable. You could call their tech department and confirm that two subs are needed for monoblocks.

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The lumin also has unbalanced outputs that can be sent to any sub that accepts line level stereo inputs.

Do you know if both of those analog outputs can be used simultaneously? The Lumin manual says to only use one of them.

You could put something like a MiniDSP Flex between the Lumin and the amps. That would avoid any potential issues from using multiple DACs and allow you to have an active crossover which could help with sub integration. You could also add Dirac for some DRC if desired.

I do not know. I would ask Lumin that wuestion

Yes, but my problem with the miniDSPs is that, from what I understand of the signal flow, the analog inputs are converted to digital, run through the DSP functions and crossover filters, then converted back to analog. This adds an extra A/D and D/A conversion in the signal path and I think it would mess up any MQA rendering that took place in the Lumin.

Yes, there is definitely a AD/DA conversion for the DSP, but I’m not sure if it would effect the MQA decoding if it has already happened in the Lumin.

MiniDSP has very good customer service, so you could always ask. They also have an active community that might be able to help as well.

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@Travis_Mowbray For the D1/2 models there is no issue using both at the same time. It’s only an issue for the transformer coupled outputs on the more expensive models.

Use the high level input of a subwoofer, e.g. from REL subwoofer.

It’s ok with Lumin D2 D1 T2, as long as you’re not causing a ground loop this way.

A/D or DSP after MQA rendering is not ideal if you care for MQA sound signature.

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Already suggested, The problem is that because he is using monoblocks, he needs two RELs.

Update: I got the two RELs. Thank you to the Roon community for being so extraordinarily helpful :slight_smile:


Once the RELs are set up to your liking, let us know how they worked out.

We all love HiFi porn. Consider posting pics here -

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