Recorded audio sounds slow

[scottbomb]

I've been using Audacity to record streaming audio for years and now all of a sudden, with no changes to the settings, the audio is at a lower pitch and playback sounds slower than normal. Imagine recording something with a cassette recorder and then playing it back with the motor going slightly slower. That's the sound. Very annoying.

Specs: Kubuntu 13.10 with Audacity 2.0.3, downloaded from the Ubuntu repo. I removed and re-installed it the other day and that seemed to have "fixed" the problem, until today. Today's recording session sounds exactly like it did the other day.

Any ideas?

[kozikowski]

That's scary. We can whip out reasons for the show to speed up. Slowing it down is harder. Do older shows sound slow as well? If you play a ten second clip, does it take ten seconds?

Koz

[steve]

In "Edit > Preferences > Quality", what is the "Default sample rate"?
Try both 44100 and 48000 to see if it makes a difference.

[scottbomb]

Sample rate is 44,100 Hz. I ran the same operation today and it recorded fine with no quality issue. It may be intermittent. Will report back in a few days.

[dfbarbour]

scottbomb did you ever figure out what the issue was? I have had this problem intermittantly. Now it seems to be permanently broken. Playbacks of recorded streams sound slow.

[Gale Andrews]

scottbomb did you ever figure out what the issue was? I have had this problem intermittantly. Now it seems to be permanently broken. Playbacks of recorded streams sound slow.

Scottbomb is very unlikely to still be reading or following this.

Please give us the required information to go on (see the pink panel at the top of the page).

Also exactly what browser are you playing the audio in and exactly how are you recording that in Audacity?


Gale

[dfbarbour]

Linux 3.5.0-17-generic i386
distro: Linux Mint 14, fully updated
Audacity 2.0.6-alpha-Feb 24 2014 installed through Software Manager
Pulse Audio volume control installed.

I was able last night to record from a streaming video after uninstalling Audacity, shutting down, restarting and reinstalling Audacity. However, I had tried this before without success, and indeed, the slow playback resumed on my next attempt to record audio from another video stream. I tried uninstalling, shutting down and reinstalling again, but the slowness continued. I had already experimented extensively with changing sample rates, quality, dither, etc., in Audacity's Preferences. Just for the hell of it, I tried changing Default View Mode from "Waveform" to "Spectrogram". Lo and behold, recording was now normal! I switched back to "Waveform" and the fix persisted. Today I started the computer from Sleep, and went back to try to record from the same stream I'd finally had success with yesterday. Again, the slow playback. So I tried setting Default View Mode to "Spectrogram" and again Audacity started recorded normally. Set it back to "Waveform" and tried recording again, and everything still seemed normal. Closed Audacity and restarted it. Again the slow behavior. Switched to Spectrogram, still slow. Switched back to Waveform, and everything normal again. I have tried this a number of times, and usually, switching the Default View Mode will fix the problem for the current session with the slowness returning again when I restart Audacity.

I still don't know what is causing the slow-sounding recording. There is a noticable pitch decrease of maybe 10% or so. This seems to correspond to the ratio between 48000 and 44100, but that could just be a coincidence.

In the past, I seemed to be able to prevent the slowness by starting the video stream before starting Audacity. This no longer works.

[Gale Andrews]

And, what browser or tool is playing the audio, and exactly how are you recording it in Audacity?

Please post the information from Help > Audio Device Info... .

Are the recorded tracks the same length irrespective of whether they play back correctly or too slow? Or is the slow track longer than it should be for the length that you recorded?


Gale

[dfbarbour]

browser: Firefox 27.0.1 (Firefox for Mint 1.0)

pulse Volume Control > Recording > Alsa capture from: Monitor of Built-in Analog Stereo

Audacity settings:
Audio Host: ALSA
Output Device: pulse
Input Device: pulse: line:0
Input Channels: 1 (Mono) Input Channel

Audacity > Edit > Preferences > Quality
Default Sample Rate: 44100
Default Sample Format: 32-bit float
Real Time Conversion
Sample Rate Converter: High Quality
Dither: None
High Quality Conversion
Sample Rate Converter: High Quality
Dither: Shaped

Audacity > Help > Audio Device Info

Code: Select all

=============================
Default capture device number: 10
Default playback device number: 10
==============================
Device ID: 0
Device name: HDA Intel: ALC662 rev1 Analog (hw:0,0)
Host name: ALSA
Input channels: 2
Output channels: 2
Low Input Latency: 0.011610
Low Output Latency: 0.011610
High Input Latency: 0.046440
High Output Latency: 0.046440
Supported Rates:
    44100
    48000
    96000
==============================
Device ID: 1
Device name: HDA Intel: ALC662 rev1 Analog (hw:0,2)
Host name: ALSA
Input channels: 2
Output channels: 0
Low Input Latency: 0.011610
Low Output Latency: -1.000000
High Input Latency: 0.046440
High Output Latency: -1.000000
Supported Rates:
==============================
Device ID: 2
Device name: HD Pro Webcam C920: USB Audio (hw:1,0)
Host name: ALSA
Input channels: 2
Output channels: 0
Low Input Latency: 0.016000
Low Output Latency: -1.000000
High Input Latency: 0.064000
High Output Latency: -1.000000
Supported Rates:
==============================
Device ID: 3
Device name: sysdefault
Host name: ALSA
Input channels: 128
Output channels: 128
Low Input Latency: 0.042653
Low Output Latency: 0.042653
High Input Latency: 0.046440
High Output Latency: 0.046440
Supported Rates:
    8000
    9600
    11025
    16000
    22050
    32000
    44100
    48000
    88200
    176400
==============================
Device ID: 4
Device name: front
Host name: ALSA
Input channels: 0
Output channels: 2
Low Input Latency: -1.000000
Low Output Latency: 0.011610
High Input Latency: -1.000000
High Output Latency: 0.046440
Supported Rates:
    44100
    48000
    96000
==============================
Device ID: 5
Device name: surround40
Host name: ALSA
Input channels: 0
Output channels: 2
Low Input Latency: -1.000000
Low Output Latency: 0.011610
High Input Latency: -1.000000
High Output Latency: 0.046440
Supported Rates:
    44100
    48000
    96000
==============================
Device ID: 6
Device name: surround51
Host name: ALSA
Input channels: 0
Output channels: 2
Low Input Latency: -1.000000
Low Output Latency: 0.011610
High Input Latency: -1.000000
High Output Latency: 0.046440
Supported Rates:
    44100
    48000
    96000
==============================
Device ID: 7
Device name: surround71
Host name: ALSA
Input channels: 0
Output channels: 2
Low Input Latency: -1.000000
Low Output Latency: 0.011610
High Input Latency: -1.000000
High Output Latency: 0.046440
Supported Rates:
    44100
    48000
    96000
==============================
Device ID: 8
Device name: pulse
Host name: ALSA
Input channels: 32
Output channels: 32
Low Input Latency: 0.011610
Low Output Latency: 0.011610
High Input Latency: 0.046440
High Output Latency: 0.046440
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Device ID: 9
Device name: dmix
Host name: ALSA
Input channels: 0
Output channels: 2
Low Input Latency: -1.000000
Low Output Latency: 0.042667
High Input Latency: -1.000000
High Output Latency: 0.042667
Supported Rates:
    48000
==============================
Device ID: 10
Device name: default
Host name: ALSA
Input channels: 32
Output channels: 32
Low Input Latency: 0.011610
Low Output Latency: 0.011610
High Input Latency: 0.046440
High Output Latency: 0.046440
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Selected capture device: 8 - pulse
Selected playback device: 8 - pulse
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Available mixers:
==============================
Available capture sources:
0 - Mic:0
1 - Line:0
2 - Mic:1
3 - Line:1
==============================
Available playback volumes:
0 - Master:0
1 - Headphone:0
2 - Speaker:0
3 - PCM:0
4 - Line:0
5 - Mic:0
6 - Mic Boost:0
==============================
Capture volume is native
Playback volume is native

[Gale Andrews]

Have you tried setting Audacity to record in stereo?

Also:

Are the recorded tracks the same length irrespective of whether they play back correctly or too slow? Or is the slow track longer than it should be for the length that you recorded?

Gale