I teach ESL to international students. I can slow down mp3s using Audacity or VideoLan, but the audio quality deteriorates if I slow the recording down more than 20%. Can I get high quality audio files off the internet (for free)?
as a musician (and an ESL teacher) can I respectfully suggest you keep some integrity and buy the music you need so us poor buggers who spend thoudsands recording it, investing in our career and being ripped of by record and distribution company and file freeloaders can get something back - what is it that makes people think if they like something and want something they have a right to it for free - it plays badly slowly because people now no longer know what real music sounds like - you sad, sorry narcicisstic - in the ESL community the majority are happy to freely share there ideas and resources - me too - for the good of all - but that shouldn't extend to ripping music for free just because you have a noble job - we all to good and noble things
The problem here is the sample rate. Because of the narrow vocal range of humans, the sample rates for voice-only tracks tends to be 56 or 64kps. At normal speed for most people, there is no discernable difference in audio quality. When you slow down the track, the more sparsely sampled tracks show obvious degradation.
As far as finding higher quality files on the net, you'll be pretty hard-pressed to do that. As I said above, if it is voice only, most sites will have low sample rate files only.
What you can try is to re-encode the mp3 files with a higher bitrate before attempting to slow them down. In some cases, you may need to use an audio grabber application while playing the actual file through the computer's sound card to get the quality you need (if your computer has good sound hardware). You will want to get a minimum sample rate of 128kps. At that rate, you should be able to slow the playback by about 50% without too much loss of quality.
plugin for WMP and Winamp
RoniMusic SlowMeDown plugin (freeware)
Amazing Slow Downer for Windows
How to Slow Down an MP3 File With Audacity
you should know that the best available audio quality is upto 320kbps. And if you slow down these tracks using audacity or VLC, there will be distortion. So the factor is not the music quality, its the software. If you need to slow down your music for professional use, you should use virtual dj or any DAW softwares such as Logic Pro (only for mac users), steinberg cubase, nuendo, reason, fl studio or ableton. Remember, there are not freewares. You need to buy them n they are a bit costly. Obviously you can download it from other souces. There you can do anything with a track. You can slow down your track by decreasing the BPM. And also can mix, edit, add.....anything!!!!!! You'll get the best result!!!!