Variation in sound level due to hardware?

[Earthlark]

I recently recorded something using Windows WASAPI and loopback by playing it in another program. I get this funny alternating pattern and I'm wondering if it's the hardware. I also tried the exact same thing on another computer and got a quieter, different waveform. It looks like overall there are still quiet and loud spots, but they're not as pronounced.

Computer 1 (unprocessed)

Alternating-Wave.jpg (320.22 KiB) Viewed 457 times

Computer 2 (unprocessed)

Alternating-Wave-1.jpg (324.04 KiB) Viewed 457 times

Computer 2 normalized

Alternating-Wave-1.5.jpg (357.32 KiB) Viewed 457 times

First of all, is computer 2 the best recording of these? Is computer 1 somehow clipping this? Next, why the different volumes; is this a function of the hardware or is there some volume that can be adjusted? (The volume of the program playing the audio was set to max.) I read a little about WASAPI, and I'm guessing it's "connected" more with the program playing the audio (which is why the microphone isn't available in Audacity)? Finally, to fix the audio, I suppose I would just normalize by section?

Mostly I'm just curious as to why I'd get these results. Thanks for your analysis.

Computer 1: 2.0.5 Windows 8.1 x32
Computer 2: 2.0.5 Windows 8.1 x64

[kozikowski]

What's the show? What are you recording for three hours?

Unless you intentionally bought hardware that changes volume by itself, it's highly unlikely that's what's causing problems -- assuming it's working OK. The software, on the other hand, is a very different story. Did you turn off Windows Enhanced Services?

http://manual.audacityteam.org/o/man/fa ... hancements

Koz

[Gale Andrews]

to fix the audio, I suppose I would just normalize by section?

You can try Compressor to reduce the dynamic range in the track.

Does the softer section sound of worse quality than the louder (or vice-versa)?

I read a little about WASAPI, and I'm guessing it's "connected" more with the program playing the audio (which is why the microphone isn't available in Audacity)?

We have not released WASAPI support for real inputs yet because it has quite a lot of technical problems.


Gale