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Author Topic: Geddes multi-sub + two-chan mains + JRiver + HTPC + HDMI + A/V pre-pro?  (Read 2254 times)

andyc56

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Hello all,

I'm interested in doing a Geddes multi-sub setup for my two-channel system.  I have recently read that JRiver has some powerful DSP capabilities, with one possible use being to take the place of a DCX2496 or miniDSP for digital EQ and/or crossover duties of a multi-sub setup.  Here is my hardware:

  • Emotiva UMC-200 A/V pre-pro (has HDMI inputs)
  • Four subwoofers, each powered by a separate channel of amplification via two stereo Crown pro amps
  • Two mains speakers, powered by two mono Emotiva power amps
  • To be built: an HTPC using JRiver for DSP?

Here is what I'd like to do if possible:
  • In software, widen the two-channel bus to 7.1
  • Center and LFE channel would be unused. leaving 6 channels remaining
  • L and R as normal, but with crossover high-pass filters using JRiver DSP
  • Left surround, right surround, left rear and right rear would be re-purposed to receive the subwoofer signals, starting out as 0.5 * (L + R)
  • Each of the four re-purposed channels would have a low-pass filter (possibly having a different cutoff frequency and/or type for each channel), and multiple Parametric EQs per channel using JRiver DSP
  • HDMI output of HTPC to HDMI input of UMC-200
  • Left and right outputs of the UMC-200 to the two mono mains amps as normal
  • Left surround, right surround, left rear and right rear outputs of UMC-200 to the two stereo Crown pro amps to drive the subs
  • All speakers set to "large" in UMC-200 with no processing: just used as a multi-channel HDMI DAC and analog volume control via the remote
  • Center channel and subwoofer set to "none" in UMC-200

Is this possible to do using HDMI and without needing a separate external multi-channel sound device to replace the UMC-200?  My source material is two-channel-only FLAC files.  I originally thought about this after reading an article by Nyal Mellor about using an HTPC in place of an A/V pre-pro.  There was also some discussion of a similar topic in the AVS Forum "Oddball Inwall" thread.

Here's one point of confusion on my part.  In the Nyal Mellor article, he uses a Lynx AES16, and it's not clear to me which functions are being performed by the mixer software that comes with this sound device, and which are performed by the JRiver DSP.  However, since I only have two-channel capability with no room for multi-channel in my setup, I had this thought of re-purposing the HDMI 7.1 rear and surround channels for the subwoofers.  If this is not possible, I might consider selling the Emotiva UMC-200 and getting something like a Steinberg UR824.

I have never used JRiver and couldn't find detailed documentation of its DSP capabilities, hence my questions here.
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JimH

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Re: Geddes multi-sub + two-chan mains + JRiver + HTPC + HDMI + A/V pre-pro?
« Reply #1 on: December 08, 2013, 02:25:06 pm »

This may help:
http://wiki.jriver.com/index.php/Surround_Sound

It would also help to nstall the software and investigate DSP Studio.
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mwillems

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Re: Geddes multi-sub + two-chan mains + JRiver + HTPC + HDMI + A/V pre-pro?
« Reply #2 on: December 08, 2013, 02:40:53 pm »

Hello all,

I'm interested in doing a Geddes multi-sub setup for my two-channel system.  I have recently read that JRiver has some powerful DSP capabilities, with one possible use being to take the place of a DCX2496 or miniDSP for digital EQ and/or crossover duties of a multi-sub setup.  Here is my hardware:

  • Emotiva UMC-200 A/V pre-pro (has HDMI inputs)
  • Four subwoofers, each powered by a separate channel of amplification via two stereo Crown pro amps
  • Two mains speakers, powered by two mono Emotiva power amps
  • To be built: an HTPC using JRiver for DSP?

Here is what I'd like to do if possible:
  • In software, widen the two-channel bus to 7.1
  • Center and LFE channel would be unused. leaving 6 channels remaining
  • L and R as normal, but with crossover high-pass filters using JRiver DSP
  • Left surround, right surround, left rear and right rear would be re-purposed to receive the subwoofer signals, starting out as 0.5 * (L + R)
  • Each of the four re-purposed channels would have a low-pass filter (possibly having a different cutoff frequency and/or type for each channel), and multiple Parametric EQs per channel using JRiver DSP
  • HDMI output of HTPC to HDMI input of UMC-200
  • Left and right outputs of the UMC-200 to the two mono mains amps as normal
  • Left surround, right surround, left rear and right rear outputs of UMC-200 to the two stereo Crown pro amps to drive the subs
  • All speakers set to "large" in UMC-200 with no processing: just used as a multi-channel HDMI DAC and analog volume control via the remote
  • Center channel and subwoofer set to "none" in UMC-200

Is this possible to do using HDMI and without needing a separate external multi-channel sound device to replace the UMC-200?  My source material is two-channel-only FLAC files.  I originally thought about this after reading an article by Nyal Mellor about using an HTPC in place of an A/V pre-pro.  There was also some discussion of a similar topic in the AVS Forum "Oddball Inwall" thread.

Here's one point of confusion on my part.  In the Nyal Mellor article, he uses a Lynx AES16, and it's not clear to me which functions are being performed by the mixer software that comes with this sound device, and which are performed by the JRiver DSP.  However, since I only have two-channel capability with no room for multi-channel in my setup, I had this thought of re-purposing the HDMI 7.1 rear and surround channels for the subwoofers.  If this is not possible, I might consider selling the Emotiva UMC-200 and getting something like a Steinberg UR824.

I have never used JRiver and couldn't find detailed documentation of its DSP capabilities, hence my questions here.

I can confirm that on the software side JRiver can definitely handle the kind of DSP you're talking about (low and high pass filters, eq, etc.) and can generally do channel routing any way you want to slice it if the hardware supports it (copying channels, etc.).  It can do almost anything a DCX can do and quite a bit a DCX can't do besides.  I currently use JRiver for a pair of bi-amped speakers which require a setup similar to what you're describing (I replace the surrounds with my left and right bass section, etc.)

Here's what I don't know, and what you'll need to investigate on your own: whether your specific hardware will allow you to do what you need to do with JRiver.  It looks like it should work fine, but I'd suggest trying it out first.  Like Jim said, JRiver has a free trial, so you can set it up and try and get things configured to see if your UMC 200 will let you do what you need to.  I suspect it will, but I've been surprised by hardware before.

If you need any help with the DSP/channel routing configuration steps, post here and I'll try and lend a hand.  There's a bit of a learning curve, but it's worth it once you've sorted it out.
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andyc56

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Re: Geddes multi-sub + two-chan mains + JRiver + HTPC + HDMI + A/V pre-pro?
« Reply #3 on: December 08, 2013, 02:54:13 pm »

I can confirm that on the software side JRiver can definitely handle the kind of DSP you're talking about (low and high pass filters, eq, etc.) and can generally do channel routing any way you want to slice it if the hardware supports it (copying channels, etc.).  It can do almost anything a DCX can do and quite a bit a DCX can't do besides.  I currently use JRiver for a pair of bi-amped speakers which require a setup similar to what you're describing (I replace the surrounds with my left and right bass section, etc.)

Here's what I don't know, and what you'll need to investigate on your own: whether your specific hardware will allow you to do what you need to do with JRiver.  It looks like it should work fine, but I'd suggest trying it out first.  Like Jim said, JRiver has a free trial, so you can set it up and try and get things configured to see if your UMC 200 will let you do what you need to.  I suspect it will, but I've been surprised by hardware before.

If you need any help with the DSP/channel routing configuration steps, post here and I'll try and lend a hand.  There's a bit of a learning curve, but it's worth it once you've sorted it out.

Thanks very much!  I am currently using a Squeezebox Touch with S/PDIF to the UMC-200, and was considering adding a DCX, but the UMC-200 has a nasty S/PDIF bug in which it cuts off the beginnings of songs which have very short amounts of leading silence in their files.  This doesn't happen with HDMI input from my laptop, so I had thought of building an HTPC for the system to replace the Touch.  When I found out that I might be able to eliminate the DCX by using JRiver's DSP and gain more flexibility in the process, that got me really interested.

I will try out the free trial and see if I can do the signal routing as needed with the AMD HDMI audio device in my main computer, which has a brand new motherboard similar to what I'd get for the HTPC if I go that route.
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