replaygain vs itunes sound check, any reason to prefer one over the other? Options

[Veej007]

hey all

if i understand correctly, replaygain and itunes sound check both do the same thing -- they write a value in the file tag that evens out playback volume. i know that replaygain seems to be preferred by the foobar/audio geek crowd, but why? is there a reason to prefer the one over the other? i listen primarily via itunes and an ipod, so is there a reason why i ought to consider doing something other than just enabling sound check? is there a way to get replaygain support into itunes/pod/etc?

thanks

[Veej007]

just realized i put this in the wrong section. sorry. mods, please move as necessary.

[Jebus]

replaygain is a pretty good algorithm, not sure about itunes. In practice it probably works fine though, and if you use an ipod/itunes setup, you should probably use it unless you encounter problems. I've tried the WMP equivalent and even that one works pretty well.

This post has been edited by Jebus: Jan 3 2006, 22:58

[atreyu]

I have an iPod, but I've disabled Sound Check and instead use MP3Gain / AACGain on all my files before adding them to iTunes. These utilites calculate the Replaygain volume for each track or album, then *losslessly* change the volume of the track to that volume. It's pretty quick, as the tracks are not actually reencoded, rather a setting in the MP3 file that controls the track volume is set. Because this is a lossless change, the volume adjustment is completely undo-able.

What I've found is that because Sound Check doesn't target as low a volume as Replaygain I often got clipping (distortion) on loud sections of certain tracks when using Sound Check. FWIW, this was using iTunes before I got my iPod. I've never heard distortion on an AACGain'd track.

I've also read opinions that iTunes' "quicky" volume evaluation often delivers poor results... i.e. that Replaygain's track analysis algorithm is superior.

This post has been edited by atreyu: Jan 4 2006, 00:17

[Veej007]

These utilites calculate the Replaygain volume for each track or album, then *losslessly* change the volume of the track to that volume.  It's pretty quick, as the tracks are not actually reencoded, rather a setting in the MP3 file that controls the track volume is set.  Because this is a lossless change, the volume adjustment is completely undo-able.

this isn't any different from the itunes sound check though, is it? from what i can tell, id3v2 has a "volume adjusment" field, and both of these tools will calculate and write a value there. itunes probably doesn't sound as good but is well integrated, while replaygain sounds better but is a bit more of a pain to implement.

is this a fair characterization?

[Mike Giacomelli]

These utilites calculate the Replaygain volume for each track or album, then *losslessly* change the volume of the track to that volume.  It's pretty quick, as the tracks are not actually reencoded, rather a setting in the MP3 file that controls the track volume is set.  Because this is a lossless change, the volume adjustment is completely undo-able.

this isn't any different from the itunes sound check though, is it? from what i can tell, id3v2 has a "volume adjusment" field, and both of these tools will calculate and write a value there. itunes probably doesn't sound as good but is well integrated, while replaygain sounds better but is a bit more of a pain to implement.

is this a fair characterization?

I don't think either of them actually read that field in ID3v2. I know MP3gain works by editing the volume in the MP3 stream itself.

[knucklehead]

These utilites calculate the Replaygain volume for each track or album, then *losslessly* change the volume of the track to that volume.  It's pretty quick, as the tracks are not actually reencoded, rather a setting in the MP3 file that controls the track volume is set.  Because this is a lossless change, the volume adjustment is completely undo-able.

this isn't any different from the itunes sound check though, is it? from what i can tell, id3v2 has a "volume adjusment" field, and both of these tools will calculate and write a value there. itunes probably doesn't sound as good but is well integrated, while replaygain sounds better but is a bit more of a pain to implement.

is this a fair characterization?

The key objective difference between the two is that Repaygain (or in my experience - MP3/AACGain) allows you the option of using album gain, which sound check does not. Sound check basically squashes out song to song album dynamics.

If you’re anything like me, and find lack of gapless playback to be a major irritant --- Lack of album gain is like having salt rubbed into your lack of gapless playback wounds.
Hate it!

(if you are one of the many that don’t seem to care about album playback, this may mean nothing to you)


On a more subjective level - Replaygain has been claimed by many to help lower the distortion levels in using the iPods EQ.
I went from went from thinking this was just another case of audiophile placebo cult circlejerk nuttiness, to believing it actually worked. What seems stranger to me is that soundcheck didn’t seem to have the same effect with about the same level of volume adjustment. I have no idea why that might be. --- (Any comments on this appreciated)

I didn’t carefully check this out in any way, so take it for what that’s worth. But it was a pretty solid impression based on what I would call not at all subtle differences in distortion levels (that is - completely unusable to ... well ... easily usable).

Anyway, the EQ distortion issue is behind me, as I don’t need it with the current generation of iPod and the headphones I use with it. But still, I wouldn’t consider not going through the extra effort to use MP3/AACGain to get the album gain effect over soundcheck.

[Otto42]

On a more subjective level - Replaygain has been claimed by many to help lower the distortion levels in using the iPods EQ.
I went from went from thinking this was just another case of audiophile placebo cult circlejerk nuttiness, to believing it actually worked. What seems stranger to me is that soundcheck didn’t seem to have the same effect with about the same level of volume adjustment. I have no idea why that might be. ---  (Any comments on this appreciated)

The reason for this is pretty straightforward, actually. It has to do with how they are applied in the iPod.

Say you're running MP3Gain on your MP3 files and not using Sound Check. MP3Gain actually modifies the MP3 file, probably reducing its overall volume. When you play this file on the iPod, and the EQ is applied, the distortion is lessened because the audio is of a lower overall power level at the time EQ is applied.

Now say you're using SoundCheck with the same exact adjustment level. SoundCheck, unlike MP3Gain, doesn't change the file itself. So after decoding, the audio is still at the higher power level. EQ is applied and then Sound Check is applied (Sound Check on the iPod is ultimately done as a power adjustment to the analog signal, it is not performed on the digital audio). Thus the distortion still exists because the EQ was applied at that higher power level of the audio.

This post has been edited by Otto42: Jan 4 2006, 07:34

[knucklehead]

Say you're running MP3Gain on your MP3 files and not using Sound Check. MP3Gain actually modifies the MP3 file, probably reducing its overall volume. When you play this file on the iPod, and the EQ is applied, the distortion is lessened because the audio is of a lower overall power level at the time EQ is applied.

Now say you're using SoundCheck with the same exact adjustment level. SoundCheck, unlike MP3Gain, doesn't change the file itself. So after decoding, the audio is still at the higher power level. EQ is applied and then Sound Check is applied (Sound Check on the iPod is ultimately done as a power adjustment to the analog signal, it is not performed on the digital audio). Thus the distortion still exists because the EQ was applied at that higher power level of the audio.

[/quote]


OK - That makes perfect sense.
Thanks.

[Veej007]

sound check it is. i'm constantly fiddling with my volume levels and am looking for a way to set it and forget it. thanks guys.

This post has been edited by Veej007: Jan 5 2006, 06:12