Dirac and room correction software

[Hifi_swlon]

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As to iTunes I have no used that in quite some time, but I would be a bit surprised if the Audio Midi settings had much of an impact.

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Unless things have changed since I used it last year, iTunes sets the sample rate to the first track played, and that's it - the rest will be played at that rate regardless. There are a few little apps (bit perfect etc) that can auto-set this for you if you have mixed sample rate files. So perhaps midi settings can get round this.

As said above, if you have mixed sample rates, then I'd definitely look at Roon (or another 'proper' player), and since you've got a pretty high-end setup, if you want to experiment with up-sampling I definitely wouldn't let OSX midi do it, but look to something like HQPlayer.

I guess we've drifted a bit off room correction here, but there are a few threads already for Roon, and HQ Player, and a lot more over at the Roon forums.