Thanks, Colin, that was helpful. In fact, it was all I needed to find a solution. I'm starting from a WAV file that has a sample rate of 96 KHz. If I simply convert this to an MP3, regardless of bitrate, I get ringing. If I convert the WAV file to 44.1 KHz before converting to MP3 I get no ringing, regardless of bitrate. (I've tested with 40 mbps and 128 mbps MP3s.) If someone comes across this post via Google etc, here's how to convert a WAV file to 44.1 KHz: - Open the file in Audacity. - Set the project rate to 44.1 KHz. - Export the file in WAV format. - That's it. If you reopen the file in Audacity you'll see that the the project rate is now 44.1 KHz, which reflects the file's sample rate. You'll also see that the file size has changed, i.e. if you're converting from a higher sample rate it becomes smaller; if you're converting from a lower sample rate it becomes larger. Colin: Thank you! - This little bit of info has been SO helpful. Questions for all: I wonder - Is this a bug, a feature or a quirk? Is it so well known within the audio community that one should start with 44.1 KHz audio data that it doesn't need to be documented? The Sound class documentation doesn't mention 'sample rate', and I haven't run accross any "must use 44.1" guidance in my travels. I'm guessing that this is simply an undocumented quirk, and that the reason it isn't documented is that Adobe simply isn't aware of it. I'm further guessing that this is because 44.1 is a fairly common (very common?) sample rate, and the ringing problem only becomes noticable with audio that is a) voice audio, and b) in a certain frequency range, and because people aren't using AIR for voice audio much. Also, I find it curious that the ringing problem occurs when I convert a 96 KHz file, which has _more_ data than a 44.1 KHz file. I would think that the converter, having more data to work with, would create a better MP3 file rather than a worse one. I'm guessing that the explanation is that the sample rate is carried over from WAV to MP3, and that Adobe's decoder is somehow optimized for 44.1 KHz. (?) If anyone has any thoughts, opinions or insights on this I'd love to hear them. Adobe: I humbly suggest that you either improve your MP3 decoder or, at a minimum, improve your documentation. Thanks Douglas
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