iPod's "Sound Check" feature

[drpeeb 10+ year member]

Just an FYI.

I recently discovered the iTunes/ iPod feature called "Sound Check". It's supposed to "normalize" the volume of all of your mp3 songs so you don't get blasted by the loud ones or need to crank up the low ones (of course subsequently getting blasted by the loud ones!).

I've tried it since yesterday, and it seems to work good.

iTunes scans all of your songs and apparently assigns a volume reduction or increase to each song, depending on how loud the song file is compared to all the others. For example, a modern song ripped very loudly would need its volume reduced, whereas a quietly recorded song maybe from the 60's or 70's would need its volume increased. I've read that iTunes makes a determination for each song and puts the required volume change info in the ID3 tags*.

The only complaint I have so far, and it's fairly minor, is that when you're in the middle of a song and want to forward to the next, my iPod seems to "forget", or stop using, the volume change factor just a split second before actually jumping to the next song. So, the problem occurs on loudly ripped mp3's: I get just a very momentary louder piece of the current song before the iPod jumps to the next song. A little irritating, but not terrible.

* I've also looked at the ID3 tags after letting iTunes scan all my mp3's and assign its volume change data. The volume change data seems to be put on the "Comment" line, and it looks like a long string of random characters. Here are two examples:

From one of my louder mp3 files: 00001B18 00001984 00004E9A 00004E72 0002E29F 0001D2FA 00008000 00008000 000098FA 00000000

From one of my quieter mp3 files: 00000150 000001BA 000006D5 000007B1 0002E675 0002E675 00004ECC 00004CB7 0002E630 0002E675

Not sure what these mean.

Click to read more...

 

[90accordman 5,000+ posts]

looks like hex edits to me

 

[Johnny Law.Lulz 5,000+ posts]

thats pretty cool. I always wondered what that does.

 

[dman4486 5,000+ posts]

it is a waste of time....after turning it on with the ipod, I can't turn the ipod up far enough to get decent pre-out for my hu.

 

[DB-Audio 10+ year member]

x2 would agree that its hex code

 

[andrewmoore13 10+ year member]

thats pretty cool. i will have to give it a shot. that shit bugs me. all of my songs by one artist are much lower so i'll turn it up then some disturbed or something loud will come on and blast me.

 

[blindskater1213 10+ year member]

I was gonna try it, but I figured it might decrease the SQ.

 

[Twisted_0912 10+ year member]

I was gonna try it, but I figured it might decrease the SQ.

i would think it would as well

 

[drpeeb 10+ year member]

x2 would agree that its hex code

Yes it is hexadecimal, not that it matters to a user I guess. I was just curious about, why they couldn't just use a "-2.3" when a song's volume needs to be reduced by 2.3 dB.

 

[drpeeb 10+ year member]

it is a waste of time....after turning it on with the ipod, I can't turn the ipod up far enough to get decent pre-out for my hu.

I totally disagree as I'm not having that problem at all. I still have plenty of signal/ volume.

I'd suggest iPod owners each try it and see for themselves, make their own determination.

 

[drpeeb 10+ year member]

thats pretty cool. i will have to give it a shot. that shit bugs me. all of my songs by one artist are much lower so i'll turn it up then some disturbed or something loud will come on and blast me.

Yep, this will greatly improve that.

 

[drpeeb 10+ year member]

I was gonna try it, but I figured it might decrease the SQ.

I have noticed no SQ degradation at all.

In fact, iTunes does not degrade the actual audio data at all anyway. It only scans it, makes a determination and then modifies your mp3 ID3 tags to add the needed volume adjustment.

The only way you could see any SQ degradation would be if your equipment needed to be turned up in order to hit the volume you want. I still say try it and see ... It's free!! And if you don't like it you can always just turn it off, with no loss/ downside.

I will say, if you have a quiet mp3, when iTunes/ iPod applies the volume increase adjustment needed to make its volume match the others, you can sometimes hear a hiss or noise ... but I'm fairly certain it's the exact same hiss you would hear if you manually turned the song up to the volume required to match your "normal" listening level.

In any case, maybe it's not perfect, I don't know, but so far I like it ... It's much better than getting blasted out of the car on some songs.

 

[drpeeb 10+ year member]

it is a waste of time....after turning it on with the ipod, I can't turn the ipod up far enough to get decent pre-out for my hu.

Also ... see my sig. I run my iPod into a line driver then the amp. It could be that's what you need, but you'd need to decide if a uniform volume level is worth adding a $20-$25 line driver.

 

[dman4486 5,000+ posts]

Also ... see my sig. I run my iPod into a line driver then the amp. It could be that's what you need, but you'd need to decide if a uniform volume level is worth adding a $20-$25 line driver.

well...without the soundcheck, I have a max setting. My hu has a live meter that shows input level realtime. Without the sound check, almost all of my music is level. It is when you don't import your music to itunes with a volume leveler that you have this issue.

 

[drpeeb 10+ year member]

well...without the soundcheck, I have a max setting. My hu has a live meter that shows input level realtime. Without the sound check, almost all of my music is level. It is when you don't import your music to itunes with a volume leveler that you have this issue.

What volume leveler do you use? I haven't heard of that so far.

Is it separate software, or an iTunes feature?