Interesting...i wonder ifbthe m2's really have a class 1???? Why do the backbeats have such great range??
The class 1, as Soundofmusic explained, needs that also the source/transmitter is class1. So, when you pair the Momentum and the Plantronics with a class 2 device, they operate in class 2.
And as you may notice if you try many class 2 headphones, each performs differently, even VERY differently in the range, from epic fails like the most expensive bt headphones ever (the BeoPlay H8, worst range ever) till remarkable results like the Plantronics or also the Beats Studio Wireless and the Audio Technica ATH-WS99BT.
Anyway, there are good news, the Japanese make two Aptx Class 1 Dongle (Logitec LBT-UAN04C1BK and Sanwa MM-BTUD43). You can buy them from Amazon.jb or in Rakuten Global.
I am tester and counselor for Avantree, a very nice Chinese Company with a nice passionate team and an excellent support, which makes very good adapters and were among the first making Low Latency Aptx adapters. I have been able to convince them to make a Low Latency APTX dongle, so that people with a notebook do not have to travel with something attached to their 3.5 jack connector, and also because technically/theoretically speaking in this way there are less transmormations of the sound (it stays digital till it reaches the headphones, while in a 3.5 adapter would be transformed in analog and again in digital).
I am trying to convince them to make it class 1. So it would not only be the only Low Latency dongle in the world but also the only class 1 LL Aptx adapter. The perfect pair for the Plantronics (which are class 1 AND low latency) but for me also for the Momentum, as Avantree has got MUCH better support than the Japanese (they did not even answer to my emails, and their dongle needs that terrible CSR Harmony software, while the Avantree will be independent, like the sennheiser BTD-500, and will be 100% concentrated in audio, no mouse connection. One thing, well done, no intereferences).
Btw, for those having a class 2 headphone, Avantree is working on a stationary adapter (bigger, powered with AC), which will probably be class 2 but will have an antenna and will have a better range than the typical class 2, something wbetween 3 and 5 times more. Low Latency Aptx too. So people with a class 2 device will be able to move around at home more.
So, you can wait and see, I will surely inform of that in my thread (see signature).