[sleepless64]

Hello there musical people,
 
I need some enlightenment here  please:
 
Using my Denon AH-D200 headphones, Headroom Portable Mini Amp  (set at medium bass, no crossfeed) connected via USB to my MacBook Pro and music files Loosless, I listened to 2 albums, with absolutely different outcomes:
 
1. First, I listened to "The Graduate" soundtrack and even at low volumes, it sounded really awful, mainly because of bass and / or mediums distortion (horrible vibration). Yes, I did try using different settings (low, medium and high bass and with / without crossfeeding in the amp) the result was only worse some times. 
 
2. Then I heard at "Notes from a hebridian Island" and it's "almost" heaven (as I've said over and over in these and other forums, I have never been able to find "heaven" with my computer / iPod sound, no matter how much I have researched, done and expend...).
 
My first (almost natural) conclusion was: "maybe the recordings", but I mean, isn't a classic OST such as "The graduate" with the voices of Simon & Garfunkel and soft guitars, drums, etc. recorded is great quality being a reissued CD over and over?
 
What am I missing here?
 
Thanks! 

 

[Joe Bloggs]

Could there possibly be clipping going on in the digital stage?  You did not mention your computer settings.  What player are you using?  Are you using any DSPs like EQ or some such?  I have nothing against EQ (in fact, I'm all for it) but with wrong settings DSPs can cause digital clipping.  Try lowering the preamp setting a few dBs below zero, if your player has such a setting.  Try zeroing out any EQ sliders that may be above the zero mark.  If all else fails try lowering the volume output at the player and at the system mixer.  Look forward to hearing back from you.

 

[germanium]

Many acoustic instruments are recorded quite loud  but they don't nessessarly sound that way when played back due to thier softer less electronic naturen Also it may have been recorded at a volume that rode the limitor & even overpowered it causing clipping then the volume was later reduced but after the damage was done  such as the signal was cliiped during recording & clipping can't be removed without special programs that can guess the the final unclipped waveform should look like (expensive programs mind you). Once you have a clipped signal in a recording from overload reducing the volume will not remove the clipping even though the volume has been reduced. It sounds like your recording of "The Graduate" has a fair amount of clipping in it given the distortion in the low to mid frequencies. This is where you will find most clipping occuring, Rarely are high frequencies clipped except when riding the peak of a lower frquency as thier energy is reduced for balance sake as well as most instruments notgenerating that much high frquency energy except synths.

 

[germanium]

 
Quote:

Could there possibly be clipping going on in the digital stage?  You did not mention your computer settings.  What player are you using?  Are you using any DSPs like EQ or some such?  I have nothing against EQ (in fact, I'm all for it) but with wrong settings DSPs can cause digital clipping.  Try lowering the preamp setting a few dBs below zero, if your player has such a setting.  Try zeroing out any EQ sliders that may be above the zero mark.  If all else fails try lowering the volume output at the player and at the system mixer.  Look forward to hearing back from you.

Yes forgot that. Settings that you make can do this as well. set everything to flat & default & see if it still sounds distorted. If not then it's your settings, if so it is the recording.
 

 

[sleepless64]

Thank you so much to both, "Joe Bloggs" and "germanium"... boy! am I learning here?... you bet! I am really having "An Education" (love soundtracks 

). I even thought maybe it was the headphones!
 
Now, I never thought of "settings", of which I am totally ignorant; are you referring to the settings in iTunes? if so, all I could see was that in "playback" I have both, "Sound Enhancer" (set to "maximum") and "Sound Check", active. Should I unselect those?
 
Joe Bloggs, do I have all or some of those settings that you mention in iTunes? (if that's what you mean). If so, where do I find them? what is the "system mixer"? what is a "DSP"?
 
I don't have any EQ active, since as I understand, in iTunes, you do that in each song (please correct me if I'm wrong) and I've never touched that.
 
Finally, I did have the iTunes volume set to the maximum, I thought, leaving that to being controlled at the mini amp...
 
Thanks again,

 

[Joe Bloggs]

Looks like Sound Enhancer is the culprit

 
http://forums.dealmac.com/read.php?4,2611622
 
No firm confirmation of exactly what this does, but it certainly seems to be a lot.  Could easily be boosting your bass into clipping.  I suppose you have tried turning it off?
 
Sound Check sounds like a relative of ReplayGain, shouldn't be causing your music to clip... but it doesn't hurt to try turning that off too.
 
You might want to try other music players too.  Maybe this one?
http://www.head-fi.org/forum/thread/539014/fidelia-os-x-premium-music-player-ot
 
"System mixer" is just my name for the volume controls on your operating system outside of iTunes.  I don't think it's the culprit, "if all else fails" in this case doesn't mean "this will definitely fix it", just means "I don't know what else to tell you to try"

 
"DSP" stands for Digital Signal Processor, it's the collective name for anything that modifies the sound in the digital domain, be it equalization, that "Sound Enhancer", or any number of more advanced controls, like crossfeed, room cancellation (replace $thousands in room treatment with a piece of software!), room effects (anybody wants to hear what it's like to listen to music in the toilet?

)
 
edit: just found some info on the iTunes equalizer
http://www.methodshop.com/gadgets/tutorials/ituneseq/
 
Bring it up using the instructions on that page and see if everything's zeroed out.  Ignore any instruction on that page about boosting frequencies.  Make sure there are no sliders above the 0dB point.  If all else fails, try turning on the equalizer (the "on" checkbox) and lowering the Preamp slider past 0dB ("if all else fails" as in "this should definitely work, unless your recording's bad").

 

[JRG1990]

Turn off everything, eq etc, check other sound processing software eq etc are all turned off soundcards etc normally come with a software suite with loads of eq options make sure there all turned off.

 

[Joe Bloggs]

^^ Yeah, that should normally work.  What I mean by asking him to turn on the EQ then turning down the preamp is, if there's any DSP he's missed that's boosting the output into clipping, turning down the preamp would fix it--but the only preamp I know of is in the EQ.  If that fixes the clipping, he'd need to go hunting for a hidden DSP in his system again until he doesn't need a preamp to prevent clipping, so he can turn off the EQ if he wishes.
 
mp3s without ReplayGain can clip the output without any DSP, however.  But this effect is usually not so obvious as to be immediately audible.

 

[sleepless64]

Thanks so much beautiful people! The problem is not 100% corrected, but it improved a lot... This is what I did:
 
I made some tests with the "Sound Enhancer "ON" / "OFF" and with the "Sound Check" too. At the end , the "Sound Check" makes no difference "on" or "off", so I let it "on".
 
With the "Sound Enhancer" it's another story: to be honest, I'm confused as to what this "Sound Enhancer" really does for sound quality, but what I discovered by your suggestions is that it is poison for the sound quality. Plain, it seems to "enhance", "increase" sounds to the point of distorting them... no matter how low I applied it, it always distorted sound, especially bass. The moment I turned it OFF, everything improved, especially bass. Let's say that the problem corrected in 80% or 85%, there's still a little distortion with bass but nothing compared to what I was listening. 
 
I'm listening to the "King's Speech" soundtrack and then to "The Graduate". Both recordings have a good deal of strings and lows. They distort a lot with "Sound Enhancer" ON, spoiling the whole experience. That thing is a killer of HiFi ideals... it makes you humble in your pretensions of depth, stereo or any other recording quality you're looking for...
 
With EQ "ON" and Preamp in "0", music sounds real nice, it distorts very little in comparison (in "The King's speech" soundtrack, each time the cellist pulled the string, I wanted to violently pull off my headphones 

 but Now, Mrs. Robbinson is seducing me as I write 

... it's like listening to another recording... 

).
 
Also interestingly, between tracks (complete silence) I listen suddenly too (in a fraction of a second) to some "noise" (bzzz). Actually, as I write I'm listening and that "bzzz" also comes and goes as the melody is playing. I don't know if there is a relation between bass distortion and this weird sound actually... I am in a room where there is a wireless phone, could that be the cause for the "between tracks" noise? cosmic noise? 

 I have my mini amp next to the PC, maybe that? 

 (I just moved but, mini amp as far as the wire allows and wireless phone to its charger / base and this "bzzz" seems to stop, yes it did...).
 
To get to that 100% improvement, does the possibility exist that iTunes is the cause? is there any other way to get to it that you could think of and share? I am also ignorant about that... is there a difference in sound depending on the software you utilize?
 
It's fair to add that this is the best sound ever I have got from a PC. Thanks so much!

 

[Joe Bloggs]

Yeah, wireless phone may well cause the buzz.  Like I said you could try pushing the preamp slider below 0 (turn up the volume on the headphone amp to compensate), if you hear any improvement you may need to hunt for more digital gremlins in your chain.  Otherwise you're probably looking at distortion in the recording or your analog equipment.
 
My player (foobar2000, unfortunately no Mac version) has a peak meter that will warn me whenever the digital output is clipping, maybe you should look for this feature in your next player.

 

[sleepless64]

Thanks JB! I did lowered the Preamp to -3 and the sound's even better. How can I "hunt" for those digital gremlins? 
 
On the other hand, do you know of audiophile players out there for Mac? or should I start a thread for that one?
 
Many thanks JB, you're not only very kind but a genius...

 

[Joe Bloggs]

Well, by "better" do you mean less clipping that you can definitely point to or just a indistinct sense of "better" that may be in your head?

The other EQ sliders are zeroed out right?
 
Like I said mp3s without ReplayGain can clip without a negative preamp setting but you were listening to lossless right?  Then I duno what else may be causing clipping.
 
Haven't touched a mac for years, so yeah, why not start a thread or search around...
 
You're welcome so far

But I'm afraid I've run out of questions I can answer

 

[sleepless64]

Thanks JB... yes, "better" means clearly less clipping, and also, sound gained more depth, clarity, etc. in general terms, all the experience improved.
 
No, the other EQ sliders are in the position I have always liked them, which is nothing special, but the typical, known EQ settings for general improvement of all frequencies. You mean I should "0" them all to see what happens?
 
Yes, all my music is Lossless formatted.
 
Gracias again. 

 

[Joe Bloggs]

But you said you'd never touched the EQ before!

 
Ok... well EQs work by boosting and cutting volume at different frequencies.  So say a bass frequency was already as loud as it could be in the recording, if you boost that frequency it will clip.
 
Just bring sliders that were above the zero point down to zero, and music should not clip anymore even when you bring the preamp back up to zero. (the preamp lowers the signal of all frequencies before any processing down the chain, so you could boost frequencies by at most the amount the preamp lowers it by without chance of clipping.)  Or even more simply, there should be no clipping if you turn the whole EQ "off".
 
If you find this to be the case, you have three choices:
 
1. dial in your settings again, but with all the sliders moved down so that the highest slider just touches 0dB--you should be able to set the preamp at 0 without clipping
2. dial in your previous settings, but with the preamp slider down below 0dB--a starting point would be to have it as low as the highest slider is high, and move down from there if you still hear clipping
3. try listening to music with the EQ off to see how you like it

Unless you have a really good idea what you're doing with the EQ, it's always good to listen to the system without it for a while to get a reference sound.

 

[sleepless64]

Thanks JB. I'll try all that...