iTunes mp3 "rustling"?

MarkW19

macrumors 65816
Original poster
Sep 13, 2002
1,209
1
Surrey, UK
I've been listening to all of my CD collection in 160kbps MP3s for some time now, but haven't noticed the following before, having just got some Genelec monitor speakers (but I now also notice it, as I'm listening for it now, on other speakers/headphones):-

Quite a few of my mp3s, mostly ones with a wide dynamic range/frequency range, ie. orchestral music, kind of "rustle", as if they're distorting a bit, when the music gets higher in volume.

All my mp3s were encoded with the latest version of iTunes on my G4 867 DDR, at 160k. It's not the speakers, or the volume or anything, because the same original CD the mp3s came from plays back at much higher volumes perfectly. I've tried a higher bitrate, but still the same - has anyone else experienced this, and, if so, short of using another encoder, what has anyone done about it?

Hope to hear from others with the same problem!

Regards,
Mark
 

GeeYouEye

macrumors 68000
Dec 9, 2001
1,652
6
State of Denial
I think it's a problem inherent to the MP3 format. There's nothing you can really do about it. But I do find that it's only really audible to an annoying degree at 128kbps or lower. Generally, re-ripping to 160 or 192. Don't know why it doesn't work for you. But be warned: from what I hear, AAC is even worse about this, so don't expect a miracle from that.
 

WannabeSQ

macrumors 6502
Oct 24, 2002
361
0
I think I am experiencing the same problem, and while it may be linked to the format and nature of MP3 itself, I think it has to do with Gain staging. I can play the same MP3s on a PC and not notice the same distortion. I believe apples audio hardware or possibly software is overdriving the outputstage somewhere in its path from hard drive to speakers. If I could, I would install an Audigy in my Mac, but i doubt they will ever write drivers for it.

Only thing I can suggest, is ripping a bit higher and with VBR on, and set to highest quality. Some people also say that using a LAME encoder is better than the one Apple uses. There is a hack somewhere to let you use LAME with iTunes, but i havent done it, nor do I know where to find such a thing. Good luck and happy listening.
 

zimv20

macrumors 601
Jul 18, 2002
4,390
9
toronto
is the distortion consistent? i.e. does it occur in the same place in every song? if so, that wouldn't rule out an encoding problem.

if it happens inconsistently (indicating it's NOT an encoding problem), perhaps your gain is set too high, either in iTunes (my volume slider is about 85% of the way up -- not 100%) or for the machine in general (my overall volume is about 50%).

if they're high, try backing them off and see if that does anything.
 

BenderBot1138

macrumors 6502
Oct 28, 2002
439
0
Rustling...

Wow, that's a real puzzler... I've been trying to play with my SoundSticks to get the rustling, and nope, not a thing. I used iTunes as well to get my CD info. hmmm... the HK Sound Sticks are different speakers than Genelecs mind you, but they are pretty interesting and I should get something.

Definitely can't be iTunes, as it's top shelf and does encoding as well as any program. I hope you're not damaging your hearing by maxing out on dB. Hearing Aid battery sales have skyrocketed, as the electronic music generation reaches maturity. They hear rustling AND ringing in their ears, and they don't need to have any mp3's playing. There is an auditory effect that occurs in humans that at high decible ranges causes shearing problems between the tectoral and basilar membranes in the organ of corti in the inner ear. Try moving some distance from the speakers to to see if the rustling stops.

Anyway, another option, and I don't know how true this might be, but is it possible that your Genelec's don't measure up to Apple's Specifications? It's a bit of an outside chance, and I know how good Genelecs are, but maybe their not quite good enough for Mac's Specs. You said you are hearing it on other speakers and phones now too... hmmm...

I feel kinda dumb for suggesting this, but since your using iTunes, what's your Equalizer setting (I assume none)?


Everything for me points to speakers and phones that aren't in step with Apple's Specs. Do you have access to speakers that Apple recomends directly (and I hope I'm not being totally goofy here - I did do a search on the Apple site and couldn't find the Genelecs). Try some Sound Sticks as a test
, although I don't think this will be your total solution as you definitely appear to be a high end sound client, hmmm quite the puzzler.
:cool:
 

WannabeSQ

macrumors 6502
Oct 24, 2002
361
0
Genelecs are extremely high quality speakers, Pro Models are used in Recording studios. We had some at the recording school I went to, 6 of em with a matching 15" subwoofer, man 6.1 on those things sounded incredible, especially when you could move the lead vocal to anywhere in the room with a trackball.... but I digress, I doubt it is his speakers.
 

BenderBot1138

macrumors 6502
Oct 28, 2002
439
0
WannabeSQ

Yea, gotta agree with you WannabeSQ about the quality of genelecs, but their absence from the Apple website is puzzling.

:cool:
 

zimv20

macrumors 601
Jul 18, 2002
4,390
9
toronto
Re: iTunes mp3 "rustling"?

Originally posted by MarkW19
I now also notice it [snip] on other speakers/headphones
this is from the first post -- it's not his speakers!
 

BenderBot1138

macrumors 6502
Oct 28, 2002
439
0
Rustle problem creates 30 odd foot of Grunts...

Yea zimv20, I thought that at first too... besides specifications, there's also some info at Apple about iTunes running slow if a person has a lot of songs in their music library...(over a thousand or something) but its older info I think, so may not have any merit here.

Real Puzzler, good catch zimv20... still might be speakers if his other speakers and phones don't meet Apple's specifications either though I guess...

Try this... burn one of your mp3's back to a CD and play it from your CD Drive like with your original CD Audio Disks. Or even if you've got a mix you've made on a CD play that from the disk and let us know if that is "rustle" free...

:cool:
 

mnkeybsness

macrumors 68030
Jun 25, 2001
2,511
0
Moneyapolis, Minnesota
i find these threads very interesting...

i've never had a problem with itunes and i have over 4000 songs and i'm running a monster cable from the headphone jack to 2 RCA into my sony stereo.

i did have a problem at my old home with a low bass sound coming through the subwoofer, but that was because of dirty power.

but now...i listen to music constantly and have never had a problem.

:D :D :D
 

springscansing

macrumors 6502a
Oct 13, 2002
922
0
New York
Re: Rustling...

Originally posted by BenderBot1138
Wow, that's a real puzzler... I've been trying to play with my SoundSticks to get the rustling, and nope, not a thing. I used iTunes as well to get my CD info. hmmm... the HK Sound Sticks are different speakers than Genelecs mind you, but they are pretty interesting and I should get something.

Definitely can't be iTunes, as it's top shelf and does encoding as well as any program. I hope you're not damaging your hearing by maxing out on dB. Hearing Aid battery sales have skyrocketed, as the electronic music generation reaches maturity. They hear rustling AND ringing in their ears, and they don't need to have any mp3's playing. There is an auditory effect that occurs in humans that at high decible ranges causes shearing problems between the tectoral and basilar membranes in the organ of corti in the inner ear. Try moving some distance from the speakers to to see if the rustling stops.

Anyway, another option, and I don't know how true this might be, but is it possible that your Genelec's don't measure up to Apple's Specifications? It's a bit of an outside chance, and I know how good Genelecs are, but maybe their not quite good enough for Mac's Specs. You said you are hearing it on other speakers and phones now too... hmmm...

I feel kinda dumb for suggesting this, but since your using iTunes, what's your Equalizer setting (I assume none)?


Everything for me points to speakers and phones that aren't in step with Apple's Specs. Do you have access to speakers that Apple recomends directly (and I hope I'm not being totally goofy here - I did do a search on the Apple site and couldn't find the Genelecs). Try some Sound Sticks as a test
, although I don't think this will be your total solution as you definitely appear to be a high end sound client, hmmm quite the puzzler.
:cool:
It's much more likely that the soundsticks simply are not able to reproduce the sound. They're still just computer speakers afterall.
 

MarkW19

macrumors 65816
Original poster
Sep 13, 2002
1,209
1
Surrey, UK
Rustling

Hi guys,

Thanks for all your replies. Just to recap:-

The quality of the Genelecs (as has been said) greatly outweighs the spec of Apple's internal soundcard, and, the same thing also happens on my MAudio card, AND on my ipod, at 160k so, the problem seems most definitely in the encoding. And, yes, it does happen at exactly the same point in the songs, as if the gain is set too high and it's distorting when it's encoding and, as such, even at minute volumes, the rustling is still audible - I don't monitor at high levels 'cos as someone said, hearing aids are quite expensive ;)

The only possible thing I can try is turning Sound Enhancer off - it's currently on 50%, BUT, with it happening on my iPod also (obviously with Sound Enhancer off), this doesn't lead me to believe it's that. Also, EQ = off.

Again, thanks a lot, your replies are appreciated, but it seems I'm the only one to witness this. Hmm ;)

BTW, I also have some soundsticks and the exact problem is also audible on them.

Regards,
Mark
 

springscansing

macrumors 6502a
Oct 13, 2002
922
0
New York
Re: Rustling problem...

Originally posted by BenderBot1138
Is your Sound Enhancer turned on and set to high?

:cool:
Yes... sound enhancer should be OFF and the EQ should be OFF. Trust me, anything else and you can leave yourself open for clipping errors during louder passages. If you have decent headphones, there's no need for either.
 

springscansing

macrumors 6502a
Oct 13, 2002
922
0
New York
If you do not have EQ on, most likely the problem is with mp3s in general. iTunes' encoder is okay, but Audiocatalyst is much better. It's only for OS 9, but its easily the best sounding encoder available, and can handle high-freq VBR encodings as well as more traditional ones. I think it costs around 15 dollars.
 

zimv20

macrumors 601
Jul 18, 2002
4,390
9
toronto
do you have the volume smoothing turned on? just curious.

also, if you have a program like ProTools, you can throw the mp3 in there and look at it visually. if there's a noise spike, it might be visible.

this would help differentiate between an encoding problem and a consistent reproduction (i.e. digital -> analog) problem.
 

LethalWolfe

macrumors G3
Jan 11, 2002
9,368
119
Los Angeles
Even though you had a very thought out post BenderBot1138
I think you're over thinking the problem. :) I have to agree w/the others that it's probably a limitation of MP3 encoding. The more dynamic range in the music the more apparent the limitations of MP3s become.

I'd bet that the majority of MP3 downloads is of music that mostly mids (pop) so the problem isn't as evident as w/a classical piece. Also, I'm willing to bet that almost everyone can hear the distortion, they just don't know what to listen for so they don't recognize it. After I took some audio production classes and record/mixed some trax in college my perception of music (and audio in general) has never been the same.

For me MP3s downloads are a nice "try before you buy" at the "standard" 128 bit rate, but if I like the band I'll got out and by the CD 'cause listening to those low quality MP3s is maddening. My own MP3s I encode at least at 192 (sometimes higher) but my hearing is damaged (slight ringing if I'm in a silent place) so whatever distortion is still there I can't hear. :(

After thought here: The distortion has always been there, but it's never been noticable until you listened to it thru such a quality pair of speakers (kinda like I never payed attention to the distortuion caused by curved CRTs until I started using a flat CRT). Now that you know what the distortion sounds like you can pick out no matter what speakers/phones you use.


Lethal
 

hesdeadjim

macrumors regular
Jul 17, 2002
194
0
Austin, TX
Honestly, it probably just the compression of the songs. It may also be the quality of the encoder, but for the most part, MP3's are not the best quality available. If you have really good speakers, which you do, the "rustling" will probably be more pronounced due to the clipping and the conversion. I would probably recommend just running if off the CD or reripping it at a higher rate. Also, you can go out and find a better encoder, but iTunes should be fine. You can also try the AAC in the new quicktime but ripping at a high rate like 160 or so. If you find something that works post it so we can get similar quality.
 

BenderBot1138

macrumors 6502
Oct 28, 2002
439
0
iTunes...

Must agree ... I've been following up on this one over the last day or so, and as little as I want to admit it, the mp3 compression is emerging as the culprit. I don't think a person would find it any different on any machine, or CD player for that matter. I am sure however that some people have Super-Hearing that would make Stan Lee's pals jealous!

springscaning makes a good point about soundsticks production of sound compared to non-computer systems. SoundSticks system frequency is 44Hz to 20kHz. The Genelec Monitor site says their frequency is 47-22kHz. Mind you I think the Genelecs can make your ears bleed. :( Since MarkW19's got SoundSticks as well (very cool), I'm thinking this is like those pictures you see in the malls where you stare at them and then see the sailboat. I'd still be interested to know if you got the same sound rustle from songs off a CD which iTunes imported as mp3. Just curious if someone with a better ear can try this.

MarkW19's summary was awesome, and thanks to LeathalWolfe, springscaning, and everyone else too, for great insights. Big kudos to GeeYouEye who banged this one out the park right off the bat.

mnkeybsness is right, these threads are really awesome... , thanks to one and all!

While maybe not directly about mp3 quality, Apple Knowledge Base Document 60784, at Note 1, talks about sound quality and mp3's. Looking at that Note, I wondered if you were to switch the setting for iTunes Importing to AIFF for a song and listen if you'd avoid eating Crowe and eliminate the Russeling...

:cool:
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.