Is "Master For iTunes Droplet" Using Same Encoder As iTunes? Options

[BDW42]

After reading some of the Mastered for iTunes documentation and downloading the accompanying tools, I have a question...

In the PDF, they discuss the previous challenges of encoding high resolution files and note the advances they've made in their new AAC encoding process, which I'm assuming is done through the Master for iTunes Droplet encoding tool provided. Anyways, I experimented with some of the recent 24/96 files I own, from the recent Paul McCartney Archive series, and I found myself quite impressed with the results.

This got me to thinking: while this droplet is aimed at high resolution files, would regular CD rips also benefit from using this droplet, as well? Today, I grabbed my AIFFs of my 2011 Smiths and 2009 Beatles remasters and tried it out and, for me, I noticed a definite improvement. The frequency response seemed better, things seemed tighter, and had some "balls" to them, and, for the first time, I had trouble discerning the AAC from the source. But before I get excited and start re-ripping my entire collection, is this just my imagination or is there really anything going on that's different between the droplet and, say, a regular CD rip in iTunes? I fear this might end up being some placebo effect. If they are different, would it be good practice to use this droplet for regular 16/44.1 files?

I'm a little fuzzy on this, and sort of new to all this, so any clarity would be greatly appreciated.

Thanks!

[Kohlrabi]

This got me to thinking: while this droplet is aimed at high resolution files, would regular CD rips also benefit from using this droplet, as well? Today, I grabbed my AIFFs of my 2011 Smiths and 2009 Beatles remasters and tried it out and, for me, I noticed a definite improvement. The frequency response seemed better, things seemed tighter, and had some "balls" to them, and, for the first time, I had trouble discerning the AAC from the source.

I'd be surprised if the AAC encoder used in the droplet is different from the standard one provided by Quicktime or iTunes. It makes no sense that a lossy encoder aimed at the human perception system gives different results for high res files and CD source files (assuming both come from the same master). The likely result you will get is that the high res files might be slightly larger due to the additional ultrasonics, though any sensible lossy encoder should not really produce files which contain any information above 22kHz, so this difference will be marginal. And this difference is inaudible, anyway.

Do you know how to perform an ABX test?

Try to perform an ABX test as suggested by dhromed, with an encode of the high res file vs. the original file, and an encode of the dithered to 16 bit and downsampled to 44.1kHz file (serving as a "CD" master) vs. the original source file. I'd be surprised if you can perform a successful ABX test on one but not the other.