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Advice Needed: 6 channel external sound card - for Richard Taylor's software based dsp

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#1
Hello

I am looking for a 6 channel EXTERNAL sound card that I can use with software-based dsp solution built by Richard Taylor for my LX Studio system.

It should work well with Linux. (I plan to use the soundcard on Intel NUC dn2820fyk or a rasp-pi, hence external)
Ideally, it should have XLR outs, since my amp takes balanced-in, but I can live with RCA as well.
Looking for something not too expensive: < 300 USD

Thanks in advance for any kind suggestions.

(I looked at review of sound-blasterx-ae-5 - but that's an internal card)
 

AnalogSteph

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#2
What sort of amplifiers are you using? Do they feature an input level control?

If you want balanced out, you are best off looking at musicians' equipment. A Behringer UMC1820, for example, would be well within your budget - 8 balanced (TRS) line-outs @ +16 dBu with 106 dB(A) worth of dynamic range. Steinberg UR44 would be another option, though if anything dynamic range may be slightly lower with that one (it uses rather dated WM8728 DACs, datasheet spec 106 dB(A) vs. the 108 dB(A) of the CS42448 on the UMC1820). Tascam US-16x08 may be another (DAC: AK4384 - 106 dB(A)).

A look at the used market for these things may well be worth it if you want something more than just "bread and butter" performance levels.

Another possible option would be one of the few consumer sound devices, like the Asus Xonar U7 MkII, with adapter cabling and three Behringer HD400s. The Asus has fairly high dynamic range at a lowish level (~110 dB at ~1.1 Vrms ~= +3 dBu), this may be better suited to driving power amps of standard gain without any input level trim.
 
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prasanth.nath
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Thread Starter #3
Thanks.

Amps: 6 channel Hypex UCD HG, accept balanced IN. 26db gain. No, they do not have input control.
Your question reminds me that I should think of volume control (ideally with remote. This means either the sound card should support volume control via remote, or I must figure out a way to do the volume control on the PC. (Argh!)
 
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prasanth.nath
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Thread Starter #5
@tvrgreek. Thanks, but I thought the ASR reviews of Focusrite 6i6 et all, weren't very flattering. Worried about drivers issue and such with Linux.


Specifying my use-case, as it is highly likely that some one has already done this before.

Speakers: LX Studio
Current path: Multiple sources --> Hypex DLCP --> 6 channel Hypex UCD --> 6 Hypex UCD amps --> LX Studio. Hypex handles the DSP parts (XO, timing etc), but has given me enough grief. So, I wish to replace it.

Music sources: I use Roon and Spotify.
Money to spend: < 500 USD.

Possible solutions:
1. Dave Reite's: minidsp nano digi (handles dsp) --> SPDIF out --> 6 dacs (egs FIIO D03K). More here: http://www.linkwitzlab.com/LX521/DSP_challenge.htm.
  • Todo: Find out if nano-digi is visible as Roon end point.

2. Use a rpi or a pc for software dsp work. Use a soundcard or 6 channel dac (with balanced outs) to feed Amps.
Example: https://rtaylor.sites.tru.ca/2013/03/20/lx521-with-software-dsp/.
Challenges:
  • Not sure about settings for LX Studio - ie, is that a literal translation of minidsp settings, or does that involve some adjustments based on measurements.
  • Richard uses mpd. Not sure if ecasound can be a roon-end point. Not sure if librespot can work with ecasound.
3. Use a dedicated DSP with onboard dac such as minidsp4x10. Measurements are not great. I can hear an audible difference between minidsp 2x4HD and Hypex DLCP.

4. Software systems such as Audiolense ... Steep learning curve.
 

AnalogSteph

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#6
6i6 only has 4 line-out channels anyway.

D03K is likely to be marginal in performance (105 dB(A) chip spec, a modest LMV358 opamp i memory serves). You'd need only 3 of 'em, not 6, so the budget should suffice for a Nano-Digi plus e.g. 3 SMSL Sanskrit 10th MkII.
 

somebodyelse

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#8
@tvrgreek. Thanks, but I thought the ASR reviews of Focusrite 6i6 et all, weren't very flattering. Worried about drivers issue and such with Linux.
I think you'd be ok with the Gen 1 and Gen 2 Scarletts, at least if you're using a recent kernel.
Todo: Find out if nano-digi is visible as Roon end point.
The nanoDigi takes stereo spdif/toslink input so you'd need something like Ropieee and an spdif output hat.
Richard uses mpd. Not sure if ecasound can be a roon-end point. Not sure if librespot can work with ecasound.
See the ecasound '-i' switch for selecting the input - with mpd Richard uses '-i:stdin' to use standard input from a pipe. If librespot or the Roon client support standard output then you can use this. Alternatively you can use alsaloop to create a virtual soundcard - librespot or the roon endpoint play into it, and ecasound uses it as a source.
 
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