AirPlay imposing low pass filter cutting off at 16,500 Htz?
I've got an iPhone 4, iPad 3, and the new AppleTV and have been experimenting.
I got a spectrum analyser to measure a chirp I created which goes from 20 to 20,000 htz. When played on the AppleTV though my roksan amp and kef speakers, (both capable of way over 20,000 htz) the spectrum analyzer shows the frequency climbing as it plays all the way up to 20,000 htz which is what the chirp I created goes up to.
The problem is, when I did the same measurement while sending the track via AirPlay, it cuts off at 16,500 htz.
I'm assuming this is a limit imposed because transmitting those frequencies higher than 16.5khtz is deemed relatively pointless and bandwidth consuming...
I wouldn't be at all bothered about this limit, I don't listen to anything other than showing the mrs the odd youtube video via AirPlay, any serious listening is done by playing the content directly on the AppleTV from my library. I'm concerned about the limit all the sudden because I've seen some pretty high end looking kit becoming available for use exclusively with AirPlay.
These apparently work great with AirPlay but not so well when connected directly. Which sounds obtuse to me, but if people are starting to produce higher end reproduction equipment for use with AirPlay, surely the quality of AirPlay should be configurable too, to remove the LPF and up the bandwidth priority the audio stream is sent with, etc...
What do others think?