Quicktime pro resampler quality? Options

[Mix3dmessagez]

I use quicktime to downsample needledrops to 48hz tvbr *for ipod use*
I've also come across foobar sox resampler which I've read is the best
I've tried to do comparisons *downsample with sox to 48000hz then convert with quicktime or convert using quicktime*
Usually the bitrates will be the same *on average* however sometimes sox downsamples will be one bit higher *on average*
I've tried to look at the individual bitrates for the first few seconds of each song *Just to see if there's a conclusive difference* and they seem to handle things quit differently, I notice the bitrate changes faster when downsampled with sox, I know that probably isn't a determinant as to quality, but it's all I know
With sox I use very high, 48000hz, 95% passband, allow aliasing, 25% phase response *someone at another forum said those are best settings*
On quicktime, best quality, variable bit rate, and recommended sample rate
I also want to know as if Sox is better I can resample all needledrops to 48hz flac *from 96 to save space*

[nu774]

If you are using MacOS X, you can try afconvert (CLI application), which lets you to control detailed parameters of CoreAudio SRC from command line options.
QuickTime is working on top of CoreAudio; AFAIK you can only configure "rendering quality" from QuickTime exporter. I don't know how this is mapped to CoreAudio parameter.

AAC codec component of CoreAudio has it's own SRC, which is not configurable in terms of quality.
This SRC is used when you are encoding to AAC and sampling rates of source/target are different;
From what I read at the Apple site, "mastered for iTunes" droplet works in two pass;
First it runs afconvert with the highest SRC setting and convert to 44.1kHz LPCM, then encodes into AAC. This way it avoids rate conversion by AAC codec component.

In the past (at the time of QuickTime 7.6.5 or so), I have heard about audible aliasing problem of QT AAC sample rate converter from a HA user.
I suppose it doesn't have such a serious one in the recent versions, but I cannot say for sure.