Subwoofer integration on one or two endpoints


I am trying to find a way to implement a subwoofer into the system on a streamer’s level.

Roon is used with stereo through a Raspberry, specifically, by connecting to an USB DAC. Since I use both convolution and parametric eq to alter the signal to main speakers, I would need some kind of a separate channel for a subwoofer. Otherwise, subwoofer would, too, get already significantly boosted low frequency signal.

Question is - Is there a way for one Roon endpoint to send two signals at the same time? One with DSP and another without?

Or, for example, can I just buy another Raspberry and make it a second endpoint just for a subwoofer and play on both endpoints at the same time?



You could, of course, use another USB DAC through a second port on the same RPi and group both resulting endpoints, while applying different DSP and what not.
Roon’s RAAT protocol is actually pretty good at keeping the digital outputs in sync, but there may be DAC specific latencies involved, that Roon is just not aware of and can’t compensate for - you may be able to measure that and correct for it yourself, though.
To keep better control of time coherency it would probably be best to use two exact same DACs, but if you’re OCD about it, there’s no way around a multi-channel DAC.

Keep us informed, what you end up with and what your findings are, please!
Happy tinkering…

Most, if not all, sub woofers will have controls to tailor the sub to suit/augment the main system. So, would it not be better (& cost effective) to introduce the sub into your system & the review the convolution & parametric equalisation with the sub working in the system.


It will definitely be an easier way to implement a volume control. The problem is the speakers are an open baffle project and there is a significant boost towards lower frequency. I would need to dial both the sub crossover frequency and volume down, and there’s an issue of different interaction of sub and open baffle to the room. I’ll definitely give it a shot, if nothing else.

I can’t afford another expensive DAC, but a separate endpoint would allow for another convolution to undo the phase shift and even time allign sub to mains. Provided that the time difference is always fix and not random.

This almost sounds like a modular drivers, especially if you add cheap raspberry with even a amp hat.

I don’t really get what you’re saying, but for your open baffle mains you DSP in Roon, send it to RPi, then go via USB to (expensive) DAC.
If so, you still need a second path with separate A/D for your sub.
If you can’t spend much more money, you may add a relatively cheap DAC HAT as an additional end point to the same RPi, do independent DSP in Roon for that zone and send it out of the HAT DAC.

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Thanks, that seems to be the best solution. I didn’t know one endpoint can run two separate signals with DSP.

Stefan, does the (single instance) of the player software running locally on the RPi (Ropieee, HQPlayer, etc) see and control both DAC HATS simultaneously in this setup?

Did this approach work?