# External soundcard/mic pre with digital out for miniDSP



## bigus (Sep 10, 2012)

Hi all, browsed through the threads here and the sticky soundcard database and did a quick search but wasn't sure I got a good handle on the options.

Looking for an external USB soundcard with mic preamp/phantom that I intend to use with a miniDSP. I will ultimately be feeding all miniDSP products in the system with digital inputs, and want to be able to emulate that when using REW. I have an ECM8000 that I bought and used many years ago, both before REW and with REW using a dbx386 that I happened to have, which I've limited to room measurements in the past but will be measuring drivers now as well, via REW as well as SoundEasy.

I would like to use loopback for timing and system calibration.

I assume the appropriate setup would be to feed the miniDSP from an external soundcard/pre with digital out. Please correct me if this is off. Any suggestions on the best device and setup to accomplish this?


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## Wayne A. Pflughaupt (Apr 13, 2006)

First, welcome to the Forum!




bigus said:


> I will ultimately be feeding all miniDSP products in the system with digital inputs, and want to be able to emulate that when using REW.


There is no inherent advantage to this vs. a standard analog feed from a soundcard.




> I would like to use loopback for timing and system calibration.


The loopback timing can only used via analog connections. Perhaps someone more knowledgeable can comment, but it seems to me that an analog loopback timing reference would be “blown out” when you switch over to a digital output.

As far as an interface, I’d suggest browsing through the myriad of offerings you can find at sites like Sweetwater or Guitar Center to find something suitable for your needs and budget. Just beware of getting something so complicated that you get stuck in what I call the “fancy soundcard twilight zone.” See here for details.

Regards,
Wayne


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## bigus (Sep 10, 2012)

OK, well if using a digital output disables the loopback reference function that is a no go for REW and sticking to the short list of recommended devices is easy enough.

As for why digital, I guess it all comes down to this being how the miniDSP's will be configured in the final system - digital input routed through the matrix, eq, xo, analog outs. This would be the case for crossover design using SoundEasy, as well as when room measuring and treatment is done later. I have used older versions of LspCAD in the past but when it came time to upgrade to a more capable modern software I chose to go with SoundEasy. Been going through the manual, not clear yet if that would cause problems in SoundEasy as well.

I suppose I could setup the miniDSP matrix to have the sum of a digital and analog input routed to all outputs, and so long as I only ever feed one or the other during system design and setup that would allow me to use REW, SoundEasy, or normal system sources as needed. But in the end I'd probably disable the analog input as the tiny amount of self noise inherent to the analog receiver would be added to the signal path. Inaudible, I know, but it would bother me knowing it was there!


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## AudiocRaver (Jun 6, 2012)

Wayne A. Pflughaupt said:


> The loopback timing can only used via analog connections. Perhaps someone more knowledgeable can comment, but it seems to me that an analog loopback timing reference would be “blown out” when you switch over to a digital output.


I do it all the time, it works just fine.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Thanks for clarifying Wayne, I was hoping you’d weigh in. :T


Regards, 
Wayne


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## bigus (Sep 10, 2012)

So if loopback works OK using a digital output, any suggestions on best device or devices to do so? Do you use an external soundcard/pre that has a digital out derived from the usb, or do you use a separate digital out, say from internal soundcard?


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## AudiocRaver (Jun 6, 2012)

I use in external USB audio interface which has its own serial digital output.

The importance of the timing loop back is for relative timing accuracy and repeatability. The technique has always given me rock steady results.


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## bigus (Sep 10, 2012)

Which device is that? Does it include phantom power/mic pre?


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## AudiocRaver (Jun 6, 2012)

Roland quad capture, with mic preamps and phantom power, 24-bit 192 kilobits, phantom power switch on the back panel, and there is no indication of phantom power on on the front panel, no LED indicator for it, a minor irritation, but on the plus side, there is digitally controlled mic preamp gain, viewable on the driver mixer panel, so you have precisely repeatable input gain settings, very unusual for an audio interface.

The unit has coax in and out, not toslink.


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