I wouldn't worry about the impulse response or ringing. I'm not sure the way we're testing with ARTA is good enough to get accurate results. I ran all of the IR tests several times, and they'd always vary in the amount and type of ringing I got. Even the NOS DACs would show ringing occasionally, just much less often than the SB1240. I'm sure some of it is improper settings, but most is just that we'd need better hardware and software to really get a good look at them. Of course, I could be wrong...perhaps we have the tools but just our methods and settings aren't right.

So far, I've had better luck checking ringing with 1KHz square waves. Even those can be hit and miss, though.

Your results look good...better than mine in many ways. Your laptop could be better, and I also didn't use a multimeter to check my output voltage. I could probably get better results that what I've posted if I toyed around more with the volume settings, which I've already done with the Metrum and NOS1704.

If your ADC was also at 96KHz, your FR would smooth out and look more like mine measured. I've seen that before when my sampling rates didn't match.

This truly is a solid little unit. Performs well and has some good features for the price, which can go as low as $60 at times. I've heard the HPO is a bit weird and might have a high output impedance, so it's not quite perfect. Built well, looks nice, easy to setup and use. If only it could do 44.1 and multiples of that and go above 96KHz. I think you'd be looking at the EMU-0404 for that.

I'll need to start putting my RMAA results in table format. Sorry for hurting your eyeballs, everyone! I might start expanding more tests as well...the THD tests are pretty interesting, the ones broken down by D2, 3, 4, etc. I'm not sure how accurate they are, but it's more useful than just THD by itself. I'm curious if any of my time-based measurements (like spectrogram) provide any valuable information...

You said you generated this in ARTA? I had a separate program that can also generate JTest files, but I was lazy and used pre-made FLAC files I found somewhere on Head-Fi. I'm curious if that would at all have anything to do with our differences, either the different generation methods (shouldn't assuming both are JTest) or the file type.

I always try to keep my tests at or slightly below 0dB in tests. Going over that was more likely to produce ill effects. If your output is at 2V you could try lowering the A/DC volume.

If I had to guess, my measurements probably show less sidebands because of all the tweaks I did to my laptop and because I run it off the battery for tests and listening. OR I messed mine up. I could retry everything set to 24/48 instead of matching hardware/software at 24/96 and just playing the 24/48 file. I didn't see any differences the first time I tried, but it can't hurt.

Perhaps I'll see how the SB1240 does with jitter and other measurements when fed through my gaming rig (without audio tweaks at all). I think I will do tests in the future with the Hanning and Kaiser windows. I think other sources of jitter measurements I've seen use Hanning or maybe flat-top, but I do like the additional "clarity" in details you get from the Kaiser windows.

All said, though, those sidebands are still below -120dB, so jitter is still quite low.

Well, I just discovered something must be up with my laptop that I am not aware of. I just did a 24/48 RMAA test running it from my gaming rig. No sort of audio tweak applied.

It measured noticeably better in all regards except for THD and IMD, which were a bit higher numerically and weren't as clean. Ahhh, WTF.

Also, firev1, I tried your JTest file, and my SB1240 also now shows jitter sidebands. The FLAC file I have does not. I'm not sure if the conversion from WAV to FLAC caused this, if it is something about the playback of FLAC, or if the file I had is just junk.

Also tried various software with the WAV file, and you can see noticeable differences in jitter results among the software.

Rather than re-do my measurements, just take everything I've done before and assume the noise floor is at least 5-10dB lower. Maybe cleaner looking in some spots, but no worse. For example, I was able to squeeze out -107dB for noise like you were running it from a front-panel USB port. I think my other tests didn't break high 90s.

I think this also shows that I definitely need to test the JKSPDIF with different computers.

Yes. Windows drivers can eff up measurements... and sound quality. I use ASIO whenever I can. Wished Audacity for Dirtdoze supported ASIO w out having to recompile it. Heard good things about Linux ALSA.

I've used ASIO, WASAPI, or kernel streaming when listening for a long while now, which is the most important part in the end. Let me see what I can do about ASIO and RightMark...it was not working properly on my laptop. I did run Kernel Streaming measurements when I could, like with the JK in the chain. Only spent maybe 5 minutes with the SB1240 measurements on the desktop. I will also double check how I had ARTA setup.

That said, I'm not sure DirectSound would account for the difference between the laptop and desktop in regards to, say, noise measurements, but it could be possible. I'd love to learn more about how that might happen.

I seem to get consistent, repeatable results when running the same sound mode. Moving to ASIO or KS generally gives quite similar looking measuements overall but with better values. I think for a basic spectrum view it's not a big deal unless huge differences become apparent, but something fine grained like jitter measurements would probably see more benefits with ASIO, if I had to guess.

At least, so far this is what I'm thinking and seeing with measurements, and I do a lot of testing and experimenting outside of what I post (though clearly not as much as I could be, but time is limited).

I will re-do my measurements with that JTest WAV file since that FLAC copy I had wasn't doing me many favors. We'll see if it affects the other DACs the same way it did the SB1240.

Edit: firev1 posted that while I was still typing. Did you also mean your RMAA tests were done with WASAPI?