Gremlins Emerge with Switch to Windows 7

CW -- Ok, that does sound like something that is settings related.

I recall seeing a number of reports of similar symptoms with USB audio under Windows 7, which, depending on the specific computer, were resolved by disabling certain power saving features. Modern processors and motherboards have features which dynamically vary both cpu speed and cpu voltage depending on how busy the cpu is. Apparently that switching can sometimes introduce glitches into audio that is being sent out via usb, depending on the specific computer's hardware design.

Try going to Start/Control Panel/Hardware & Sound/Power Options, and selecting "High Performance."

Also, next to where it says "High Performance," go to "Change Plan Settings" and then "Change Advanced Power Settings." Expand the + sign next to "Processor Power Management," and under that expand the + signs next to "Minimum Processor State" and "Maximum Processor State." Set them both to 100% if they are not presently set that way.

If that doesn't help, you can restore the original default settings on the page that appeared after you clicked "Change Plan Settings."

There are probably also some power saving features that can be enabled or disabled in the computer's bios. As you may realize, the bios is entered at startup, before Windows starts to load, by pressing some keyboard key that is probably specified in the computer's manual.

Hope that helps,
-- Al

Elizabeth,

I like to have everything on one machine, and as a frequent participant in the forums, you should know that "audiophiles" often have a compulsion to buy and configure new hardware whether or not an older device works properly.

In addition, my netbook has been on for 8-16 hours a day for about two years, and dropped in the driveway a couple of times when rushing to work. So overdue for a new machine.

Elevick, yes, I don't even think about internal sound cards - all my audio goes out via USB into my Behringer DEQ2496 and/or an Audio Research DAC 5 at the moment. For headphones, I use a NuForce DAC which sounds pretty good.

As Al points out, however, there are still settings to configure the audio which can affect the sound.

Al - thanks and I will also check the system and power usage settings.

At the moment, the Sound shortcut can see that my playback device is "SPDIF Interface" which I don't think is strictly true since I am using optical out via a Behringer interface box to the Behringer DAC.

But somehow sounds pretty good this morning, so when in doubt: reboot.

Still there are things that bug me. If I right click on the SPDIF Interface icon and choose properties, there is a "Levels" tab which seems to function as a volume control.

This is counterintuitive to me as I am trying to export bits, not levels.

I will post more as I learn if any other Windows 7 users might be interested.

CW,

Sounds like that "Levels" tab may be a digital volume control (always a big no no since they trade resolution when controlling the volume). Try setting it to maximum and see if it sounds better.

Dick

CW,
Make sure you are bypassing the internal windows mixer. SPDIF settings should not be coming into play when using USB output. In another current thread (near the end of it) here somebody posted a link to the dCS "cookbook" for setting up computers (MAC and windows) software to get "bit perfect" output. Reading a file, converting to PCM and sending the bit stream to USB port is a simple task that requires little resources. You just have to make sure that software stays out of the way as much as possible and not tamper with the bits.

since this is a laptop its likely that you are only willing to go so far, i.e. you have to strike a compromise between a dedicated server and a multitasking machine. The biggest degradation to audio transparency is (a) the audio hardware limitations (b) the jitter introduced by cycle stealing between computer processes... your audio card may have practically no jitter in a test lab situation but in a real life PC that doesn't happen without tweaking.

1) run your laptop off outlet power

2) setup a custom power configuration with all hibernate/sleep/idle options disabled... anytime the machine has to rouse hardware(video/CPU/HD/USB) from a power saving state it introduces audio degradation

3) if your BIOS has power saving options, note the defaults and disable (video/C1E) when playing music. Restore when on battery or your battery life will suffer

4) analog laptop sound card output is usually not great. Use ASIO if your only choice is analog out. Otherewise try to use digital to an external DAC. Kernel streaming is actually better than ASIO but can be more challenging to get working without stutters and dropouts

5) get DPC latency checker from Syscon. try to get your latency below 300 microseconds

6) once you have your latency cleaned up disable all audio buffering in your playback program or put to the minimums possible. I find that when I increase the buffers beyond the minimum for the output mode, the stereo image collapses.