Headphone Connections and Output Modes

The other day I bought my first set of wireless headphones (the Bang & Olufsen H7). I’ve been experimenting with ways to tie them into my audio system, and want to make sure I understand the configuration options with Roon (which I’ve been using since earlier this year).

My main digital music library and Roon Server are on a Mac Mini, which I’ve connected via USB to a Peachtree Nova 150 integrated amp. The amp has a 1/4" headphone jack, but I don’t yet have the right cable in case I want to use my H7 phones wired to it. I expect that if I do that, I’ll be able to get bit perfect output (as I can when I play hi-res content from the Mini through the Nova 150 to loudspeakers). Correct?

If I use my MacBook as an endpoint, using “built in output” in exclusive mode with the headphones wired to the MacBook’s headphone jack, I can get bit perfect output of hi-res content through to the phones. I can get a purple light. However, in this mode, apparently there is no way to get a Bluetooth wireless connection. “Exclusive mode” means Roon takes control and precludes “OS mixing” needed to support a BT device. Right?

If I use my MacBook as an endpoint using “system output” instead, then I can get a Bluetooth connection, but without bit perfect output of hi-res content through to the phones. At best I only get a green light connection.

Am I correct that there is no way to get bit perfect (purple light) connections with Bluetooth headphones?

First, bit perfect transport is relevant only to digital links or outputs. Once converted to analog, such as at a headphone jack, bit perfect no longer has any meaning.

Next, to my knowledge, Bluetooth audio does not currently include a lossless mode. Some Bluetooth devices support multiple codecs, but even the highest quality codec, aptX, is mildly lossy. And if not lossless, then bit perfect is not possible.


^ All that makes sense. However, when I play ALAC content to my MacBook Pro, set to Built-in Output in Exclusive Mode, Roon shows a lossless signal path, with or without headphones wired into the MBP’s headphone jack. Is this an error? Or is it just not characterizing the complete signal path?

When I play ALAC content to my MacBook Pro, set to System Output, Roon shows a “high quality” signal path (with a green light at the Output stage.) Isn’t this what I also should expect to see with wired headphones while in Built-in Output in Exclusive Mode?

Again, the analog output is not relevant to bit perfect transport, is beyond the purview of Roon.

Built-In Output through the mini TOSLINK optical digital output – assuming the most common vintage MacBook Pro – can be bit perfect. System Output will not be bit perfect, since it runs through the OS Mixer.