BitPerfect is...erm...perfect!

All very true and this is the problem that I have with claims of bit perfection and clarity, because if differences exist between software, either only one is correct and provides bit perfection, or none do.

I'm sticking with iTunes in the unfiddled with config for now and if I need a change, then the best proposition is probably EQ.

Bit perfect is an unaltered passthrough of an audio signal. There will be no processing, filtering, equalising or resampling. Basically, what is on the file is the file when heard.

Which is presumably what Mac OSX iTunes does when EQ is switched off?

Don't know mate.  I won't even begin to claim I know how it all works, but the various software players I've tried (BitPerfect/Amarra/Pure Music) all do sound a bit different.  I don't know why or how they work, it's probably more complicated than any one of them being less or more 'bit perfect' than the others.  I think it's something to do with how they directly interface with your, erm, interface, often in 'hog mode' so not even OSX itself can use it.  Those in the know also say that there are SQ gains to be made from directly playing from RAM rather than a HDD, which is a feature most of these players offer.  Sure enough, both Pure Music and Amarra sound best to me when used in this way. Again I don't really know why it works.

In a word, yes.

I did read someplace that Bit-Perfect minimises on CPU usage, not sure if how much of an infuence that has in terms of sound but...

Maybe.  I know Amarra certainly doesn't minimize memory usage. When I had the trial version running on my 4GB iMac, if I told it to buffer a full album to RAM it used to moan repeatedly about low memory if I had any other app running at the same time, even iTunes itself (Amarra will happily run without iTunes using its own Playlists function).  There's even an option to close down OSX Finder to release even more memory.

A right pain in the rear then. How did it sound though compared to Bit-Perfect?

Doesn't bit perfection vanish as soon as you adjust the volume inthe digital domain? In any case, much of the stuff I listen to is less than lossless and I'm happy, so don't really see that it's of much consequence.

I stand to be corrected on specificas, but it won't change that I CBA and am not really that bothered.

Yes I believe so, similarly if you use a DSP.

TBH, I have strted using mine to tone down a bit of room resonance and a bit of upper lift to counteract my ageing hearing;so technically it's no longer bit perfect, but then since the FR of my speakers in my room is probably far from flat then it's a moot point anyway.

That's an interesting thought. I never really paid much attention to the volume control in iTunes, presuming that it ran with no loss in resolution (cuts no bits).

ItS certainly true that some digital attenuation will cut bits but not all, that includeds hardware aswell as soft and afaik Foobar runs at full resolution (as well as my DAC) when the volume is used.
For arguments sake let's say iTunes doesn't run at full resolution, the only way that would be an issue is if you used it to control the volume and not used some other means to control it, meaning running the iTunes attenuation at full tilt to get over the issue of bit reduction.

Would be interesting to know how the iTunes volume works.

Note sure about iTunes in Mac O/S environment, but J River's DSP operates in 64 bit  in W7, so there is no loss of data when it is downsampled and streamed apparently. 

Have just downloaded - and I'm hearing now't...

Umm, so Bit Perfect doesn't work with wifi/an AirPort Express, then??