[Rijnton]

Recently I bought the Philips Fidelio M1BTBL (Bluetooth) headphones for use with my iPhone 4S and, at least for me, they sound great. They support apt-x, but unfortunately the iPhone does not have apt-x.
Meanwhile I saw that there are bluetooth transmitters available, e.g. the Kokkia i10s, that add apt-x support to the iPhone. Now I wonder if this really will improve the sound of the headphones. FWIW, most of my files are ALAC (Apple Lossless) and the rest are mp3's at 320 kbs.
Thanks in advance for any help.

 

[squallkiercosa]

Usually around Head-fi people tend to be audio purists, only a few uses bluetooth. In any case, there´s more information in autres threads: 
My suggestion: save your money, why carrying a dongle if the whole idea of bluetooth is not carrying extra weight. 

http://www.head-fi.org/t/601665/what-are-head-fi-members-views-on-apt-x-lossless-codec-over-bluetooth

http://www.whathifi.com/forum/android/apt-x-or-one-x-bluetooth-issues

 

[heatofamatch]

Apple doesn't support apt-X. What they do support is AAC via bluetooth. In theory, this means any AAC file or stream should be sent directly to a compatible bluetooth receiver and be decoded there (instead of decode-encode-transfer-decode).
 
In your case, a better-sounding bluetooth receiver will probably depend on two factors:
1. the receiver is designed/engineered with a better implementation of the usual SBC codec
and/or
2. the receiver has a better sound in and of itself (e.g. better amplifier).
 
If you don't use an apt-X compatible phone, the receiver might as well not have that feature, and you'll be falling back on SBC and the quality of the receiver's analog output.

 

[Rijnton]

Thanks for the replies.
@heatofamatch:
It is not completely clear to me what you mean. The receiver, the Philips M1BT headphone, is compatible with SBS, AAC and Apt-X. The sound is imho very good. It also got a "Best Wireless Headphone 2013" award in What HiFi magazine.
But what I would like to know is if the sound will be better when I use a bluetooth transmitter with apt-x on my iPhone, for instance this one:
http://www.amazon.com/KOKKIA-Luxurious-Transmitter-authentication-receivers/dp/B008PWN0I4