Active / Passive with USB DAC


Novice Member
Hi - I am using Sennheiser Momentum 3 headphones with a Dragonfly Black USB DAC plugged into my iPhone through the camera adapter. I have an EQ set through the Sennheiser app as I don't enjoy a flat EQ. This works fine when I use the Headphones in Bluetooth mode or through the 3.5mm cable with the Headphones switched on.

If I use them in passive mode (ie the Headphones switched off) I don't get the EQ / ANC etc which I fully expect, so in thios case I have to use an app such as Spotify or Boom which has an EQ within the app to tune the sound to my taste. Annoyingly Tidal doesn't have an inbuilt EQ so Tidal through Boom has to suffice.

So why don't I use them in active mode? Well this is my question. If I am using the Dragonfly DAC I have read that it will then also use the inbuilt DAC in the headphones. Is this right? Is this technically processing the audio twice from digital to analogue then digital again? I'm about to get a Dragonfly Red and want that to be the sole processing not the DAC in the headphones. Is this the case or am I over analysing it and won't tell the difference? Am I still getting the 24/96 from Tidal if the headphones process it too?

Sorry for all the questions, I just want to use the DAC and the headphones to get the best sound possible that also suits my EQ tastes too!


Novice Member
Yes, you would be better of using USB in the M3 than wired analog if you are in active mode. When powered on the M3 will convert the analog signal back to digital (to apply volume control, EQ, and ANC) and then run it through its own DAC at 16/48. When the M3 is in passive mode it is effectively just a loudspeaker and does not do any DSP. You also would be better off using qobuz or amazon HD if your DAC doesn't include an MQA renderer. There are 3 MQA unfolds. The first is implemented by software (e.g. Tidal) in the form of a "core decoder" and the latter two are implemented by hardware called a "renderer". An MQA file is technically either a 24/44.1 or 24/48 FLAC file. The core decoder in Tidal will unfold this to 24/88.1 or 24/96 respectively. This is as far as you can go without an MQA renderer. With qobuz or Amazon HD you can reach as high as 24/192.
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