Hey everyone. Got a question that has been stumping me for awhile now. Back in January I had to re-rip all of my CDS. I chose iTunes AAC (using both my iMac and Macbook to make things a bit faster) at 256K at both standard and variable bitrates.

The problem I'm having is that compared to other audio files downloaded from the iTunes store and other services like eMusic, the files I ripped are EXTREMELY poor quality/volume. I normally connect my iPhone to my car stereo's head unit using an aud cable, and when a song comes on that I ripped, I have to increase the volume a ton usually from 18-20 for a downloaded song to about 30. Overall sound quality is terrible as well....very tinny, low bass levels....it almost sounds like a transistor radio.

Is this typical of the iTunes AAC encoder? Is there something I'm missing? I even went back and re-ripped some of the files using the MP3 encoder and the same low volume levels are there.

Any help would be appreciated.

Thanks

-ron

iTunes 7.7 had a problem with the AAC Encoder. In VBR Mode it was always using 160 kbps, not matter what setting you did use. This is fixed in iTunes 7.7.1
I would check first that sound enhancing settings and equalizer are set to a normal level.

There's definitely something going wrong. The volume of rips might be a *bit* lower than a download, but I find iTunes rips @ ~160 VBR very satisfactory.

Perhaps have a look at Get Information on some of the tracks, to see if there's anything funny set. If it's happening with both computers, that would seem to rule out anything in the hardware, at the ripping end.

Hmm. Cable between iPod and head unit still OK???

Ron, is there any chance that the only problem is the lower volume and that you're pehaps just imagining the quality aspect. Have you compared the sound of the aac files with the original cd? I'm suspecting that the difference could merely be that the downloaded files have had their gain adjusted (eg "normalized") and possibly had some added EQ as well.

Yeah, this is what I'm thinking, especially if the CDs the OP is ripping tend to be older material, pre-"volume wars."

Sorry for not checking in on this a bit sooner, been on the road for the last few days.

All of the suggestions offered so far are much appreciated. I haven't had time to implement them all, but I'm sitting up at my friends apartment and can't sleep so ran the following test.

I made a playlist in iTunes of a few songs I typically have to make significant adjustments to the volume for. I alternated ripped songs and downloaded songs to get the most noticeable effect. I'm on my MacBook, listening through Shure Ec2 buds. When I ran through the songs, there was no noticeable difference in volume at all other than perhaps difference in recording levels.

I then copied the playlist to my iPhone, since this is the output device I use in the car, and swapped the Shures over. When cycling through the songs from the iPhone, there was a VERY significant change in volume levels between the songs, just as it in the car. It was not at all like the playback from the MacBook via iTunes.

Strange huh? Even more strange...I then went and adjusted the volume slider under the "Options" tab for the low volume songs. When played back on the iPhone they had a slight increase in volume level, but still falling short of the downloaded, much louder songs. BUT, when played back through iTunes they sounded MUCH louder than the downloaded songs. This makes sense, seeing as how in iTunes, prior to adjusting the volume slider, they were equal.

It seems as if the iPhone playback of songs encoded in iTunes (aac/mp3) is falling short for some reason. Or iTunes itself has some sort of software normalization of volume levels other than Sound Check, since I do not have that enabled in Preferences.

When I get back home, I'm going to check the ripped files against the original CDs (something I have done before, but will do so more thoroughly) in iTunes as well as CD playback on the car stereo simultaneously with playback from the iPhone. But something is not right here...

Ok, bare in mind that I don't have/use itunes or AAC or a mac or an iphone. So obviously I'm guessing but here's what I think.

1. There's nothing wrong with your AAC files other than that they've been made from a lower volume original CD (without any additional volume "normalization" or EQ'ing).

2. Itunes has the option to automatically normalizes the volume during playback so no problems there.

3. The iphone doesn't normalize the volume (or that option is not set) so you notice your AAC files are quieter.

4. The volume slider you are adjusting is a "reference level" and itunes is normalizing relative to this reference level, thus making your song actually play back louder under itunes.

Ok that's all just guess work, so take it with a grain of salt until someone with more experience with AAC and itunes chimes in.

BTW. Does anyone know if there's an equivalent or "mp3gain" for AAC ?

There is indeed such a thing as aacgain. It's made by the same developer i think and is available at rarewares.