[Savonet-users] encoding aac - metallic sound and poor quality

[Alexandru M. <ale...@gm...>]

Hi!

The last days I decided to add a new AAC stream to my radio. I already 
broadcast aacp and mp3. I wanted to add this stream especially for 
mobile listeners which connect using Tune In 
(http://tunein.com/get-tunein/). Not sure if tune in supports AACP, the 
mp3 is at 64kbps, so I wanted to lower the bitrate and mantain the 
quality using AAC. I don't know what's wrong or what I'm doing wrong but 
the sound's quality is very poor.

I have tried the following  AAC streams:
- stereo, 32KHz,48kbps - metallic sound
- stereo, 44KHz,48kbps - less metallic sound, but still not smthg that I 
want to broadcast
- stereo, 32KHz,32kbps - a small metallic sound -> the best combination 
found so far between freq. and bitrate.
- stereo, 32KHz,24kbps - the sound is chopped and the quality is very low.

Also tried another combinations, still no good quality. I also listened 
to another radios broadcasting the same kind of music, an AAC stream at 
24kbs,32kHz - acceptable, quite good quality even there is a "small" 
metallic sound.
48kbps,32khz - very good sound quality.

I don't know what to do/try next. Have you experienced some kind of 
problems while streaming aac? It is because of the codec? Is there a bad 
combination of channels, samplerate and bitrate?

Thanks.

Alex