I have recently found - trying to convert my music to sell on iTunes - that in .mp4 extention, the song sounds fine, but the moment I change the file extention (of the very same file) to .m4a, it sounds 'spacey' or as if their is a reverb filter. Changing the same file's extention back to .mp4, and voila: it sounds well again. The very same .m4a also sounds fine in real player. I have tried various .m4a converters, and they all do exactly the same. Somehow, iTunes reads the .m4a differently, adding a reverb like effect.

This frustrates the hell out of me - any help?


(Thing is - I need to send it as .m4a, and not .mp4, as .mp4 is supposed to be for video on ipod only).

Thanks

Did you make sure Sound Enhancer isn't enabled in the iTunes preferences? It's on by default under Mac OS

You have made my month - thanks a lot. I thought it might be something to do with that , but somehow I kept missing what I was looking for (looked for EQ). Found the 'sound enhancer', switched it off, et voila!

Strange that it doesn't do it with mp4 files; only with .m4a's.

Thanks yet again

It sees the .mp4 extension as more a movie than an audio file from my experience with iTunes.

I haven't found that to be the case. I just checked four of my Macs, and none of them had Sound Enhancer turned on.

I agree that Sound Enhancer is anything but. Crap processing if you ask me. the one time I checked it out years ago, they were basically increasing the level of the L-R component to increase stereo separation, and also tweaking the EQ a bit. Neither improves sound quality. It's essentially a higher-tech version of the old "loudness" control boost found in old stereo systems.

--Vidiot