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TheIceMan · May 7, 2004, 10:59 PM

I've noticed that there is a difference in sound quality (loudness and clarity) when you play an mp3 using QuickTime and when using iTunes.

I'm on QuickTime 6.4 and iTunes 4.5.

I know there is a difference if QT is used to play mpeg videos/movies. I'm not talking about that. What I mean is when I use QuickTime to play an mp3 the sound is louder and clearer than when it's done through iTunes. I'm playing the exact same mp3 using QT and iTunes, (Alice Deejay-"Will I Ever")

I also tested different Equalizer settings (Bass Booster, Dance, Hip-Hop, Pop, Rock, and at the default "None"), but it didn't matter. QT was still louder and offered a nice, deep bass sound to it.

Both sound settings on QT and iTunes were at their maximum.

Has anyone else noticed this and more importantly, any ideas on how to get iTunes to match the sound quality of QT? Sounds crazy I know. Any ideas?

f1000 · May 8, 2004, 08:43 AM

Turn off "Sound Check" in iTunes.

-Maverick

TheIceMan · May 8, 2004, 10:21 AM

That helped, but it is still not the same. QT is still louder and has more bass. Even setting the iTunes equalizer to "Bass Booster" does not help.

f1000 · May 8, 2004, 10:44 AM

Then try turning off iTunes' "Sound Enhancer" as well. I can't hear any difference in playback quality between QuickTime and iTunes through my MDR-NC11 headphones.

akuma-x · May 8, 2004, 11:13 AM

Well from what Apple thinks it's a feature. I for one can not stand the new sound settings for iTunes 4.5. it sounds like sh*t to me. Apple needs to go back to the old way iTunes handled sound IMO.

"The reported sound loss with ITunes 4.5 is a feature called Log Volume. It is indeed different in that the output volume is not linear. But, it really shouldnt make any difference because 0 and 100% is going to be the same no matter what version you run. Your preferred volume settings will just have to be adjusted to a new position on the slider."

Check out the Apple support board for more info.

http://discussions.info.apple.com/we...sq.0@.599abd39

f1000 · May 8, 2004, 11:25 AM

I don't see how log volume would attenuate sound differently at different frequencies. Furthermore, at 100% volume, log and linear can be made exactly the same.

Here's one way to do it: 100 * ln(x+1)/ln(101) = y

From this equation,

x = 0, y = 0
x = 50, y = 85
x = 100, y = 100

TheIceMan · May 8, 2004, 09:01 PM

akuma-x: Thanks for the info.

f1000: I'm sorry but I did not understand what you wrote, especially that mathematical equation. Simple, layman's term please.

wataru · 10:02 PM

They changed the scale of the volume from linear to logarithmic. All that means is that as you move the slider up, the volume does not increase at a steady rate, but rather logarithmically. Go look at a graph of y=ln(x) to see what this looks like.

In the end, however, maximum volume is the same whether the scale is logarithmic or otherwise, so this feature has no impact on sound quality. You just can't compare volumes between a linear scale and a logarithmic scale, because they aren't the same at any point except for the endpoints (and possibly one or two points in between, depending on the functions).

And that equation is nothing a high school (middle school?) graduate can't understand. It's an example of a function that is zero at zero, 100 at 100, but scales logarithmically in between. Just plug in the x numbers and you get out the y numbers he gave. If it was linear, for x=50 you'd have y=50. But since it's logarithmic you have y=85 (actually 85.194...).

TheIceMan · May 9, 2004, 01:03 AM

While I do appreciate the math lesson, I don't think that it explained why there is a difference between the sound quality when an mp3 is played through QuickTime and when it's played through iTunes.

These explanations refer to volume. What I'm asking about has to do with the difference in quality and loudness when comparing 2 applications. I simply want to know why there is a difference and how I can adjust one to match the other.

Thanks.

wataru · May 9, 2004, 01:30 AM

I just checked things out on my system, and I found that for the song I tested, iTunes's max volume was less than QuickTime's until I turned off the volume normalizer thing. After that they sounded identical. So I have no idea what's going on with your system. Are you sure you're not imagining it?

If you still claim that the max volume for iTunes and QuickTime are not the same, then you definitely have a difference in settings somewhere.

TheIceMan · May 9, 2004, 06:54 AM

Originally posted by f1000:
Then try turning off iTunes' "Sound Enhancer" as well. I can't hear any difference in playback quality between QuickTime and iTunes through my MDR-NC11 headphones.

I think that did the trick. BTW, what does the sound enhancer do (except for the obvious)?

f1000 · May 9, 2004, 07:36 AM

Originally posted by TheIceMan:
While I do appreciate the math lesson, I don't think that it explained why there is a difference between the sound quality when an mp3 is played through QuickTime and when it's played through iTunes. These explanations refer to volume. What I'm asking about has to do with the difference in quality and loudness when comparing 2 applications.

That's what wataru and I were trying to say: Apple's implementation of log volume should not have adversely affected iTunes' playback quality.

Originally posted by TheIceMan:
I think that did the trick. BTW, what does the sound enhancer do (except for the obvious)?

Try Googling

Spheric Harlot · 06:32 AM

Originally posted by TheIceMan:
I think that did the trick. BTW, what does the sound enhancer do (except for the obvious)?

It's a sort of aural exciter. It shifts and phases certain frequencies to give the impression of more "sparkle" and a "broader" sound on crappy equipment.

This is a sampling of "pro" opinion from the Metric Halo Mobile I/O mailing list:

I do a lot of work in the in the field of spatial audio and have some
knowledge in this area. I found the sound enhancer for Itunes really
messes with the sound quality (both in the spatial and frequency
domain). I highly recommend for any professional audio use (or any use
for that matter), turn off Sound Enhancer in Itunes The Sound Enhancer
on/off is located in the Itunes preferences.

Turn it OFF. It does horrible things.

In layman's terms: it completely ****s up the sound beyond all recognition.

Turn it off at all costs if you consider the artists'/engineers' idea of what the music should sound like to be of any importance.

-s*

TheIceMan · May 10, 2004, 07:47 AM

Spheric Harlot: Thanks. Now that's the answer I was waiting for. You're my "Google."

Powaqqatsi · May 11, 2004, 02:14 PM

OMG I just tried that log volume thing (my itunes is always at 100% since is manage the volume with my external amp) but oh boy does this suck! You can't fine-tune the volume at all ! The first half of the slider is quite useless... Anyway it's not a problem for me, but it could be for others.