Severe playback distortion due to low buffer setting[SOLVED]

[Okieman]

Here are screen capz of the three sections of the Windows sound control panel. Ignore virtual cable; it's a week-old effort to attempt to route Audacity to the output via another route, and haven't completed the experiment. The problem started long before it was installed. HTH.

http://www.mediafire.com/view/?lqid8pqz281lckd

[steve]

What happens if you set the recording input to "M-Audio deleta 1010LT 1/2" ?

What is "M-Audio deleta 1010LT Mon Mixer" ?

[Okieman]

I'll have to test that setting and find out tonight.

Plus I'll have to read the manual re the Monitor Mixer.

[Okieman]

What happens if you set the recording input to "M-Audio Delta 1010LT 1/2" ?

No change.

What is "M-Audio Delta 1010LT Mon Mixer" ?

From the manual: "... a hardware digital audio mixer built into its PCI controller chip. It accepts digital audio streams from all hardware inputs and all outgoing software audio devices, mixes them with 36-bit internal precision and then provides the mixed output to one or more locations."

[Gale Andrews]

For completeness, uncheck Overdub (on/off) and Software Playthrough (on/off) in the Audacity Transport Menu. Increase "Audio to buffer" in the Audacity Recording Preferences (it affects playback, too).

Otherwise I suggest you get the zip versions of Audacity 1.3.13, 1.3.8 and 1.2.6 here:
http://code.google.com/p/audacity/downloads/list?can=4 .

Extract each zip to a different folder. Try each one. 1.3.8 and 1.3.13 each had newly updated versions of the third-party PortAudio Audio I/O interface which we use. I would not recommend 1.3.8 as it has lots of other bugs which had been fixed by 1.3.13.

1.2.6 is somewhat lighter and more responsive than 1.3.x and 2.0.x and of course much more contemporary with XP.

There are other experimental builds of the current Audacity code you could try. It is possible that a build supporting WDM-KS could help you (lower latency, bypasses the Windows Kernel Mixer, giving direct access to the audio drivers). DirectSound (supported in current Audacity) does that too (on XP, but not Vista and later), but WDM-KS is faster.


Gale

[Okieman]

I will work on that tonight. Gale, thanks for sticking with me. I've been in other forums where helpers got distracted or lost interest. I very much need to solve this problem, partly because I pretty certain it's going to turn out to have a simple solution, but more importantly if I have to switch to a different audio waveform editor, it's going to cost me hundreds of dollars!

[Okieman]

SOLVED!

But not how I expected. I had resigned myself to using one of the older versions. Unzipped 1.3.13, launched it and while there looked at preferences. Overdub and Software Playthrough were already unchecked, as was the case in 2.0.3 where I had trouble. I did change the "Audio to buffer" setting from 25 to 75. Opened the most recent mp3 exported from my project, and Audacity 1.3.13 played it perfectly. Which I more or less expected. Closed the app.

Launched 2.0.3 and looked at three preferences just mentioned; they were already at the unchecked first two and altered third from my first test. I wondered if both version stored preferences in the same place? Opened the same file and Audacity played it perfectly. Surprised me. On a hunch, I started backing off on the "Audio to buffer" setting in increments of 10. No problem at 75, 65, 55 or 45. At 35 it was somewhat horrible, and at the original 25 it was horrible as usual. Aha! Thank you all!

[Gale Andrews]

Glad it was solved and yes, 1.3.x and later all store their settings in the same audacity.cfg file.

But 100 ms is the default audio to buffer and it's expected to start failing on Windows below about 30 - 40 ms. I was assuming you had it on the default 100 ms and needed to put it up to about 200 ms.


Gale

[Okieman]

The answer as to why it was set at 25 instead of 100+ is lost in the mists of time. In other words, a couple of years ago.

Another user error. Sigh.