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can't hear first second of some tracks
Posted: Fri Jan 09, 2009 8:54 am
by lukeprog
I've mixed together a podcast: 6 tracks of audio.
During playback or after exporting, very often the first second of a track's audio will not play. For example a track that starts at 0:12 where I say, "So, you're saying that..." only plays back "...saying that..."
But it's random. I'll set the cursor right before that track begins and hit play a bunch of times and 1 out of every 10 tries it will play the whole thing instead of cutting off the beginning of the track.
I've tried doing Mix and Render. I also tried doing that to just two tracks at a time until they are all mixed together. Same problem. The first second or so of some of my tracks are cut off.
Any ideas what causes this? Is this a bug?
Re: can't hear first second of some tracks
Posted: Fri Jan 09, 2009 9:14 am
by lukeprog
I'd still like to hear if anyone knows why this "bug" happens, but I found a workaround:
You can just add a second of silence before the track and then re-position it. That works.
Re: can't hear first second of some tracks
Posted: Fri Jan 09, 2009 2:35 pm
by steve
lukeprog wrote:During playback or after exporting, very often the first second of a track's audio will not play.
And this happens whether you are using Audacity to play back, or if you are playing an Exported audio file in a media player?
If that is the case then it is most likely that the problem is with your sound card settings. Have a
thorough look to see if your sound card has any effects such as "noise reduction" or "automatic gain control" (AGC), or "noise cancellation" or any other effects - if it does, then switch them off.
Re: can't hear first second of some tracks
Posted: Fri Jan 09, 2009 3:28 pm
by stearman65
I would ask how you are re-starting your playback? via the cursor or using the blue "skip to start" button on the info bar. I always use that, if the sound starts immediately, placing the cursor in the correct location can be difficult.
stearman65
Re: can't hear first second of some tracks
Posted: Fri Jan 09, 2009 4:29 pm
by lukeprog
Yeah, it's both in playback and with exported audio.
No sound card settings like that, no.
I just place the cursor about a second before, say, track 2 begins, then hit Spacebar to play, let it play for three seconds (enough to notice that it cuts of the beginning of track 2), then hit the spacebar twice again to play that part back again. Or I can highlight that selection and just let it play in a loop; it almost always cuts off the first second of track 2.
Re: can't hear first second of some tracks
Posted: Fri Jan 09, 2009 4:40 pm
by steve
lukeprog wrote:Yeah, it's both in playback and with exported audio.
In that case it must be a sound-system problem rather than Audacity.
Although you have not found any sound card effects, my guess is that you have an on-board sound card (RealTek?) and that in fact there are some effects settings, but you haven't found them.
Set the system tray to show all icons, then go through each icon in turn - the settings are normally hidden away in one of those icons.
Re: can't hear first second of some tracks
Posted: Sat Jan 10, 2009 2:30 am
by lukeprog
It's SigmaTel. The only options I have are "Allow reconfiguration pop-ups" and "Enable power management"
Re: can't hear first second of some tracks
Posted: Sat Jan 10, 2009 10:49 am
by steve
lukeprog wrote:It's SigmaTel
That's the other one
Both RealTek and Sigmatel are very commonly used for on-board sound. They work reasonably well for voice recording, playback of computer pings, and playing music through your PC speakers, but are not generally very high quality - mostly because the manufacturers use cheap components in the analogue circuitry so as to keep the cost of the PC down, but also because the main computer board is an electrically noisy environment.
To keep the sound from being too noisy for the majority of users (this does not include people who want to do high quality recordings) the manufacturers employ various kinds of tricks to "enhance" the sound. These "tricks" include various kinds of noise suppression methods, and the effect that you are getting is a symptom of this.
Usually there are ways to switch off at least some of these "enhancements", though I guess that the designer of your computer decided that you would not need to do that.
The only other options that I can think of are to either use the workaround of adding a bit of silence to the beginning of tracks, or to upgrade your sound card.
Note that if you burn your files to CD, then the CD should play correctly on a CD player without having to add silence to the beginning.
Re: can't hear first second of some tracks
Posted: Sat Jan 10, 2009 6:15 pm
by lukeprog
Note that if you burn your files to CD, then the CD should play correctly on a CD player without having to add silence to the beginning.
Really? Even though a rendered WAV file plays incorrectly?
How bizarre.
Re: can't hear first second of some tracks
Posted: Mon Jan 12, 2009 4:40 pm
by steve
From the description so far, it sounds like the audio is actually present in the file (you should be able to see the waveform in Audacity), but you just don't have sound coming out (your sound card is not playing it - it's not "switching on the audio output" until a couple of seconds after the start). If that's correct, then yes a CD from the file should play perfectly on a CD player. Try it and let us know if it does.
lukeprog wrote:Note that if you burn your files to CD, then the CD should play correctly on a CD player without having to add silence to the beginning.
Really? Even though a rendered WAV file plays incorrectly?
How bizarre.