Update: I just found out that Audio CD's are NOT supported by Sound Check. I thought they were because the files that had been upploaded via CD before I installed iOS 5 were changed when I turned on Sound Check. However, I just uploaded another album with a CD and it sounded distorted as if it were an mp3. It seems the only file that gets fixed by Sound Check are files downloaded from the iTunes store.
Update: Sorry for the triple post. Anyway, I've discovered that the files that were already on your iPod before iOS 5 and the files you add afterwords react very differently when operating Sound Check and/or using the Volume Adjustment bar to remove the distortion.
If the song was already on your iPod when you downloaded iOS 5 and it is from the iTunes store or an Audio CD, it is supported by Sound Check. Mp3's however, are not.
If you are adding a new song to your iPod after having already updated to iOS 5, then only songs bought from iTunes are supported by Sound Check. Both mp3's and files taken from an Audio CD aren't supported if they are added to your iPod after having downloaded iOS 5, so you will have to fix them via the Volume Adjustment method I mentioned two posts ago.
I've also noticed a strange, and very annoying, glitch when trying to adjust the volume on songs you're adding after updating to iOS 5. While adjusting the volume levels in iTunes and listening to the song on your iPod to make sure it sounds good, if you adjust the levels while a song is playing (regardless if the song is playing or paused) then something very weird will happen. The very first song on that album will have a very different volume level than the rest of the songs on the album.
For example, I was adjusting levels on a particular album and was using the second song on the album as a reference to listen to. After I had fixed the distortion, I went and checked the rest the rest of them and I noticed that the first song on the album was much louder than the others, but every other song was perfect. Also, if I listened to the first song from start to finish and let it continue into the second song, the second song also had the same boost in volume! But, if I paused the song, switched to a different song, and then replayed the song again, the volume levels were normal again!
I've also noticed that the opposite can happen. As in, the first song on the album will be lower in volume than the other songs and when you let the first song continue into the second, then all the remaining songs are much louder. But, if you pause the song, switch to another, and come back, and play it again, the volume level is the same as the first!
I don't know why or how this happens, but if it does happen to you, what you need to do is balance out the volume levels between the first song and the rest of the album. For example, if the first song is too loud and causing the whole album to be louder than normal, then you need to lower the volume of the first song so that it levels out. The opposite rules apply if the rest of the album is too loud, in which case you need to lower the rest of the album so it matches the first song's volume.
Honestly, I'm getting really sick of this. I'm very glad that I've been able to figure out , for the most part, how to fix all these problems but I just wish Apple hadn't even touched the EQ in the first place. All my music was at a glorious and comfortable listening level and it downloaded and synced perfectly. Now, I have to adjust levels for the individual album, make sure not to glitch out certain songs, etc.
*sigh* Being an audiophile is tough work...
Well I hope it is (updating now), but installing a new version of iTunes doesn't really affect my iPhone does it? I managed this distortion by resetting all my per track volume adjustments to 0 (you can do this in the XML file to make sure it really is 0, you can't really tell with the slider bar and I couldn't find a right-click type thing to centre it on 0). The audio no longer distorts on my 3GS but I still think it sounds different (using no EQ etc.).
It seems like it was a weird bug because the only things I had volume adjustmet on for were about 10 music videos, all the remaining 2000 or so audio tracks had none. Yet the 'unadjusted' audio tracks still played back distorted. Basically, I have no idea how Apple implement their DSP and link it to the iTunes XML file.
Ok I have not tried the update yet and reading the last few posts it seems like its not worth the hassle trying. I'm starting to get the feeling apple doesn't want us to put our own music onto these devices and have set up the music now mainly for iTunes download? I don't know. This is what I've done to try and make the music sound better and a little louder.
First select all your music in iTunes go to the options and move the volume slider say -10% from 0 and press ok, let iTunes save that setting,
Then select all your music again go to options the volume slider will be at 0 so tick the box to the left of the slider think its headed "volume change" ?? Then press ok and let iTunes save again,
Link up your iPhone and sync, this should bring the volume of your music back to 0 (same instruction from page 5/6)
Now what I did was to select one of my really bassy tracks or one I knew was having the distortion problem and pressed play,
I turned the volume of my mac up 100% so that it's coming out of the speakers I plugged my headphones in,
Now go to advanced and go to equaliser,
You will see a vertical slider called pre amp,
Either with your speakers or headphones (better) and the track playing move the pre amp slider up until the track runs into distortion,
be careful it's massively loud and can damage your hearing, my old Dj ears are a little use to it but only for a short period
When you hit distortion back off or bring the pre amp slider down a little until the distortion has gone,
Save this as an EQ preset and name the preset
Ok select all you music again right click option below the volume slider tick the EQ box and select you names EQ preset now move the volume slider to +25/30% and press ok
Let iTunes save the volume and sync your phone.
As long as you keep your named EQ preset and tick the box in options each time you can play around with the options volume from +25/30% to more or less %
Give it a try and see how you get on its late and I'm tired but if you need help ask I monitor this site praying for a fix which doesn't seem like its coming. Cheers apple
Just to add and it's a pain in the *** theoretically you would have to find the loudest most distorted track and use that as the master for tuning the pre amp volume, what I mean is if you set the pre amp volume for the loudest track every other track will not distort, play around with the pre amp volume and the options volume together and see how you get on.
I think a lot of people are missing the point. Regardless of iTunes settings, the sound is also distorted when listening to music and talk radio on the INTERNET through the iPhone safari application. It has nothing to do with iTunes. It is a bug in the operating system, not iTunes. If the bug is fixed, then iTunes will play normal again too, but changing settings in iTunes means nothing when listening to music on apps such as "Pandora" and "iheart" radio. Everyone keeps talking about iTunes, it has nothing to do with that.
True and I completely agree with what you say, iTunes is not the problem but while apple completely ignores the fact that this is a problem what else are you suppose to do. The phones settings are limited so it's only playing around with iTunes whether it helps or not is better than waiting for a fix. I've moaned enough about it if you read the earlier posts and apples technical department for which I was put thru to palmed me off with the "thats strange haven't heard about that one" if you want to storm the barricades I'll be first in line with you but for now any help or slight fix or even finding out what they've done, how they've done it must be a help for now at least.
To back up what JT314 is saying one of my music apps Groovemaker has just flashed up with an update it reads:
"resolves an issue that could cause distorted audio using ipad 2 or iphone in some circumstances" I haven't updated the app as I'm still major p.o'd with apple about all this and it just seemed like evidence that apple has changed things first the music now apps are maybe releasing updates because there also affected. Conspiracy theories? All I know is shove iMessage I had 3000 txts a month anyway ios 5 has condemned my listening pleasure to s**t do I turn to the archos, android, windows darkside or can apple pull their head outta their a**