External hard drives and sound quality


I've just about filled up the internal hard drive on my Macbook with music files and am now looking at external hard drive options. Was wondering whether folks report any difference in sound quality when playing files from an external drive versus the internal?

I'm especially interested in hearing people's experiences using wireless hard drives. An Apple rep told me it would be no problem, as the hard drive wouldn't directly interface with the USB output, but I of course always like to be skeptical of anything an Apple rep says.
coverto
The issue here is the whole idea that something may in fact be happening to alter the sound that you do not understand. It is just not possible, no matter how extensive your expertise, for you to know all that could alter sound. I apologize if this is difficult for you to digest and realize it can be humbling.

To clarify again...I found the difference in sound to be subtle and not worth influencing my decision which HD to purchase. This occurred when trying different NAS units in my system. It had nothing to do with internal vs external drives rather two NAS drives. I was not aware of any faulty hardware or ground issues and am comfortable assuming there were none.

This reminds me very much of a discussion I was having on another forum trying to convince someone that digital cables can sound different. His "expertise" was making it very difficult for him to digest this fact.
Once people encounter something counter-intuitive like digital cable affecting the sound they tend to stretch this to every possible case. Different sound of NAS drives could be related to something else then drive itself - for instance music was ripped two times to drive and is not identical - even if this is the same song/piece, or system was just turned on while second drive was tested later when system was warm and tweeters (ferrofluid) warmed-up. In addition to this we have placebo effect. In coducted tests people often swear to hear big difference while in reality they listen to exactly same set-up.

I remember joke about Russian scientist that was removing flea legs one by one ordering it everytime to jump. When he removed last one and flea did not follow his order he wrote a note "Removing all legs makes flea deaf"
One has to be very careful with conclusions.
Kijanki, I agree with your last post but there are some things in the second to last that I take exception to. Nobody has even hinted that the drives are corrupting the data. Both you and Mapman use that as some sort of proof that the drives can't alter the sound when nobody has suggested that is the reason. It is like Mr Stacy said, I said, and even you alluded to in your last post; there are things that can affect the sound that we don't understand. Stating all hard drives sound the same because they all deliver the same bits ignores all else. OK, I said that before and yet I still get bits is bits tossed at me so evidently I'm not getting my point across.

BTW I don't use any feedback in my amps and think they sound wonderful.

So Russian fleas respond to a verbal commands? I would like to see that :>)

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All of a sudden in the last week the sound in my headset has gone to hell. Used to be absolutely great! Now, a lot of clipping or static around the edges of the music. Could my External HD be acting up or could it be the Toslink "Out" from the Mac Pro? Maybe the answer is here in this thread. I use iTunes which has always served me well.
So when my investment house calculates the interest on my portfolio, all other things being equal, does one computer drive give a different number than another? Or is this unknown, not understood phenomena involving different hard drives only discernible by audiophiles with highly resolving systems?