Dual card set-up?

JLM1948

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Hi,
Exploring the possibility to extend the frequency domain, I may consider a system operating with 768kHz sampling rate.
However, AFAIK, there is no affordable soundcard capable of that, so I was thinking of combining an evaluation card from TI
http://www.ti.com/lit/ug/sbau335/sbau335.pdf
in conjunction with a DAC such as this one
or similar.
My question is how would REW (and Windows 10) manage the two different drivers, one for send, the other for receive?
 

John Mulcahy

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Input and output devices can be different for the Java drivers, but on Windows they are limited to 16 bit. The workaround is to use an ASIO wrapper like FlexASIO or ASIO4All that combines multiple devices into a single synthetic ASIO device. Or host the cards on Linux or macOS, where the Java drivers can be used without limitations. Edit: removed macOS as it doesn't work reliably above 192 kHz.
 

JLM1948

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Input and output devices can be different for the Java drivers, but on Windows they are limited to 16 bit. The workaround is to use an ASIO wrapper like FlexASIO or ASIO4All that combines multiple devices into a single synthetic ASIO device.
OK, thanks, I'll try that with two "ordinary" soundcards for validation. Don't want to jump the gun and spend about €600 without a reasonable conviction it would work.
Or host the cards on Linux or macOS, where the Java drivers can be used without limitations.
My only experience with Linux was a Ubuntu install and it was painful...
Edit: removed macOS as it doesn't work reliably above 192 kHz.
Anyway I've long given up on Macs.
 

JLM1948

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John, I have decided to take a very prudent approach and I have installed FlexASIO, with two soundcards:
One is the Tascam 2x2HR I got recently, the other is the NI Komplete that I has retired because the output went noisy.
So I set up the Tascam as output and the NI as input, I ran a frequency response in measure mode, which is what I regularly do, however the level falls out rapidly at ca. 22kHz. I have checked that it's the output that gives up.
When I use the Tascam for both out and in, the output goes up to about 70k.
So it sems somethiing tells the Tascam card to insert the single speed filter instead of the quad speed.
I have checked that the driver is FlexASIO and the SR 192k.
Any thought?
 

John Mulcahy

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Make sure the rate you want to use is set as the default format in the Windows audio properties for each device, since the driver is a wrapper around the underlying WDM driver.
 

JLM1948

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Thanks for the tip, John. I never had to do it before, so it took me some time to find where it was hiding.
In the french version of Windows, they have translated "Other soundcard parameters" by "Parameters of other soundcards". Doh!
It works fine, now, so I'll proceed with purchasing the ADC and DAC.
 
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