# "ASIO" vs DRM compatible and CarPC Frontend friendly "E-MU Directsound"



## t3sn4f2 (Jan 3, 2007)

*"ASIO" vs DRM compatible and CarPC Frontend friendly "E-MU Directsound"*

Thought you guys would be interested in some Rightmark Audio Analyzer measurements I ran on an Foorbar ASIO and Winamp Direct Sound output from my E-MU0404PCI sound card. ASIO is known to be the preferred way to output audio from a PC when you are concerned about quality. Directsound is a Windows friendly protocol that allows you to do things like mix audio streams or play DRM protected music.

Both results are based off a Toslink S/PDIF loop back style signal chain. Cheapo fiber cable was used.

I did a something a little different to be able to register a more accurate output measurement. The RMAA software has a loop back test option, but if you test that way, you are limited to recording (ie measuring) at the resolution you are testing (ie 44 kHz 16 bits, CD audio). That's because RMAA won't let you play and record at different rates. What I did to get past that issue was save the test file and play it from Foobar2000 and Winamp instead. That allowed me to raise the recording resolution bit rate to 24 bits which puts it at a quality level so high that it would not contaminate the output's measurements. Results are a combination of output quality PLUS input quality.

I also added the results of what would be a perfect test score. This is derived by analyzing the test file using RMAA. 

Also included are the results of a test run identical to the Directsound settings, but this time with 8dB of digital attenuation from the E-MU software mixer (24 bit I/O, 32 bit processing). This is not like a "WAVE" attinuation in the windows XP sound levels. It is the full volume XP WAVE output sent into the 0404's DSP hardware mixer and attinuated from there. 

Results for each output are super imposed on one another in order to show a difference if one exist. Anything in white is considered perfect. So as a result, if you see white somewhere it means that whatever color (ie output) is around it is has degraded by that much. 

I also zoomed in on the first few graph results in order to show more detail of the differences. I didn't do the rest because it would be pointless . Please note the frequency and decibel scale increments in order get an idea just how much change there is.

*Results:*

*Summary*











*Frequency Response*











*Dynamic Range*











*THD + Noise (at -3 dB FS)*











*Intermodulation Distortion*











*Stereo crosstalk*


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