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Looking for an USB soundcard with S/PDIF in and out for DSP room correction et aa

Raticosa

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Hi everyone,
I'm a new forum user (but I read it since a couple of years), I kindly beg your pardon in advance if I am posting an already discussed post and I ask your help because I'm looking for a decent (that is not extremely cheap but neither too expensive) external USB soundcard with optical S/PDIF input and outputs. I don't care of analog RCA inputs and outputs (so no need for hi-end DAC and ADCs), only optical in and out. It is for Hi-Fi stereo (L/R) only environment, no 5.1 or 7.1 or Dolby DTS interest, just PCM coding in/out for Hi-Fi purposes, at minimum 48kHz.
My goal is to "play" with PC-based room correction DSP software (like Equalizer APO with linear-phase EQ like QRange) to correct the acoustics of my living room (I already made a full acoustic treatment and I want to add DSP correction capabilities too).
For this purpose I am currently using a cheap (but pretty decent, at list for test purposes, not for definitive use) USB soundcard Behringer UCA-222 but it has only S/PDIF out, and I would like to avoid the ADC conversion... ideally I would like to perform the DSP EQ in digital domain (digital source optical out --> soundcard S/PDIF input --> PC-based DSP --> soundcard S/PDIF out --> built-in amplifier DAC via S/PDIF optical in) in order to make only the final DAC conversion through the hi-end DAC built into my Marantz PM6007 integrated amplifier.
I found only cheap soundcards (on AliExpress and Amazon) based on the C-Media CM6206-LX chipset but in most of them the S/PDIF in-out is passthrough only (so not useful for DSP purposes).
Thanks for everyone who will help.
Gianluca
 

mdsimon2

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The options below from miniDSP are not too expensive and work well. They also have a bare board (kit) version of the usbstreamer but it appears to be out of stock.


Whatever product you end up with make sure you understand how it implements clocking. The miniDSP products can be clocked either via the SDPIF input or their own internal clock and you really want to ability to clock the output via the SDPIF input. In comparison the hifime S2 digi is a SPDIF in/out device but it does not have the ability to clock the output via the input SPDIF clock which makes it rather useless as a I/O device.

Michael
 

mdsimon2

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As mentioned above in my experience this device does not work well in this application because it lacks the ability to use a single clock for input and output which results in audible dropouts. It worked fine for capture only and worked fine for playback only but does not work well for simultaneous playback/capture.

Have you used this device in an SPDIF I/O function with computer based DSP as the OP described? Reason I ask is it is possible the issues I observed were Linux/RPi specific although when used on a Mac it shows up as completely separate input / output devices with no clocking options so I am somewhat confident the issues I observed are inherent to the clocking options.

Michael
 
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Raticosa

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Hello Michael, hello staticV3,
thank you both for fast reply, much appreciated!

Looking at MiniDSP website seems the MCHStreamer kit would be the best choice as it has both optical TOSLINK and coaxial S/PDIF in/out capabilities (depending on the firmware you will load). Moreover it costs a bit less than the USBStreamer B (15 USD less) even if has no external case (requires a DIY case).

Would be interesting to know if someone else in this forum already used this (or the USBStreamer, that is very similar and shares same chip) to implement an application like mine, and also if Windows can recognize it without any problem for application like Room EQ Wizard (e.g. to generate test signals over optical/coaxial out for DAC converters and similar items).
Gianluca
 

mdsimon2

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Hello Michael, hello staticV3,
thank you both for fast reply, much appreciated!

Looking at MiniDSP website seems the MCHStreamer kit would be the best choice as it has both optical TOSLINK and coaxial S/PDIF in/out capabilities (depending on the firmware you will load). Moreover it costs a bit less than the USBStreamer B (15 USD less) even if has no external case (requires a DIY case).

Would be interesting to know if someone else in this forum already used this (or the USBStreamer, that is very similar and shares same chip) to implement an application like mine, and also if Windows can recognize it without any problem for application like Room EQ Wizard (e.g. to generate test signals over optical/coaxial out for DAC converters and similar items).
Gianluca

I've used both the USBStreamer and MCHStreamer in similar applications using software DSP but not on Windows. They work fine on Mac / Linux for what you describe, again the flexible clocking options help here as they can easily be used with or without a TOSLINK input.

I've primarily used them with ADAT interfaces as they can act as USB to ADAT playback devices which is helpful with old Firewire proaudio interfaces (MOTU Traveler Mk1, RME Fireface 800) that can act as standalone ADAT DACs.

Michael
 
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Raticosa

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Hello Michael,
digging a bit into this forum I found a discussion where it states that Equalizer APO will not work with ASIO drivers, so looking at the MiniDSP products you mentioned seems they have only ASIO drivers for Windows :-(
A pity, because they seem very consistent products..
Thanks for your precious help.
Cheers.
Gianluca
 

staticV3

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@Raticosa Equalizer APO works via Wasapi Shared and DirectSound APIs. Those APIs work with every USB DAC, including the miniDSP.
 
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