Volume Structure under Windows 7

[Renz]

Good Day,

I have a question for anybody that has previously looked into the audio signal path within the windows 7 software structure.

It appears the the level I am getting out of windows, when I look at the windows mixer does not match with the level I am sending out of my audio software within the OS.

Check out the attached video, and compare the level of the internal source with the general output level it seems to be inconstant. Further more it also seems like there is some sort of compression algorithm with a long attack involved.. Look at how long it takes for the level to reach its nominal level.

There is apparently a lot going on but not sure where I am supposed to look into as I cannot find any signal flow diagram that relates to this Microsoft product.

Note that in this example I am first playing a fully masterised tune from media player (its the exact same problem with VLC) and then a sine wave at 0DBFS and also a normalized pink noise.

>>https://drive.google.com/file/d/0B1rwadXoy_PIYTh3YzFOSlhJa0E/view?usp=sharing

 

[dbaxter]

You'll need to look not at Windows 7, but at the driver software for the specific audio card or on-board audio of your computer. Many of them try to do you a favor by adding effects to make the sound "better". You'll have to look closely at the documentation and/or Help files to find the settings to allow for a clean, straight output. You will have to post the manufacturer of your sound hardware before any of us can begin to help.
Also be aware, your computer will not be on Windows 7 much longer. If it even gets close to the internet, Microsoft will update it to 10.

 

[Renz]

The drivers seems to be and interesting prospect of culprit. Is there any "no frill" driver anymore out there? ASIO for all? KX drivers (DIscontinued)
NOTE: Windows 7 will continue working as long as I have decided.

 

[FMEng]

Yes, the choice of audio card and drivers determines what happens with audio on a Windows computer. If you want professional results, use professional hardware. The are many excellent pro and semi-pro sound card choices now for very reasonable cost.

Also note that Windows 7 has a design flaw in its sample rate conversion that causes distortion. Every Win 7 computer used for serious audio work should have this patch applied.
https://support.microsoft.com/en-us/kb/2653312

As for Windows 10 upgrades, it is not difficult to resist the Borg. Never let Windows Update run automatically. Never let it install KB 2952664 or KB 3035583. When those are on the list, right-click and "hide" them. They'll come back from time to time. Long live Windows 7!

 

[Renz]

Yes indeed my friend. However there got to be some lore out there about signal flow inside windows. I have posted the same thread on sevenforums/audio to see what's out there. Have you try to run that same experiment I did with your OS whatever it is? Try with different drivers see if you get a difference. Have you already bench tested your professional drivers or do you just take them for granted? >> I will try a few different things and will get back here to post my results.

I would be interested in knowing what you guys get in terms of fidelity to your source signal.

 

[MNicolai]

In my testing in Adobe Audition on Windows 7 using a tone generator, tested with various tones.

Tone Level.......VU Meter
-0dB................Full
-3dB................3/4
-6dB................1/2
-12dB..............1/4
-48dB..............0

These results were with my usual EQ bypassed on my Realtek ALC892 audio codec.

My tests show my driver settings do directly effect the output VU. If I change my EQ or my environment settings, Adobe Audition shows consistent levels with all effects bypassed but the overall output VU includes any effects processing via my audio codec.

In light of this, I'd wager Windows 7 ain't your problem.

 

[FMEng]

Yes indeed my friend. However there got to be some lore out there about signal flow inside windows. I have posted the same thread on sevenforums/audio to see what's out there. Have you try to run that same experiment I did with your OS whatever it is? Try with different drivers see if you get a difference. Have you already bench tested your professional drivers or do you just take them for granted? >> I will try a few different things and will get back here to post my results.

I would be interested in knowing what you guys get in terms of fidelity to your source signal.

I've got a radio station full of Windows 7 machines and using pro audio cards from Digigram, Echo Audio, and Audio Sciences, among others. When the machines get installed in a studio, I routinely test them for unity gain in and out using tone. So, yes I have bench tested, and they always pass. With a good card and drivers, the performance limitation is the card circuitry, not the OS.

I have seen drivers for non-pro sound cards do goofy things, like default with some kind of AGC turned on that drives any and all audio into mild clipping distortion. Another sad case was a driver that switched itself from line level to mic level at seemingly random times. I have also measured sound cards that couldn't do better than a 50 dB signal to noise ratio. There is some real garbage out there.