Originally Posted by
dumdum
Update, I have invested in a Topping D10, reason being... using my iPhone as a source I have a 12v converted Apple TV for a digital streamer previously and noticed more detail, so the topping followed so I can build a dock to integrate the iPhone XR into the car properly
so I broke out the umik and rew and using the exact same 16bit, 48k pink noise file I measured the response from each of three sources (alpine 178bt via bt and usb, and also topping d10 via some 75ohm van Damme coax with rean plugs as 75ohm rca plugs don’t actually exist technically, nearest are crimp on Neutrik plugs, but even they don’t meet the 75 ohm standard to which bnc is ‘the connector’ of choice)
so I was expecting a different freq response maybe to explain the detail I was hearing, for example cymbals sounding like actual cymbals with nice decay and a little clearer
so imagine my shock when the response from 150-19k was bang on the same!
what I didn’t expect was the difference at 20k (I cant hear it so not too fussed!) of approx 8db, for the first time it didn’t drop off the planet!
but more serious was the low end... the alpine over usb and bluetooth closely resembled each other, literally mirrored each other to 0.1db, this explains why by sounds similar to usb... the usb input isn’t making full use of the extra digital data in the stream vs bt, anyway I digress, the low end showed a massive (7db at 20hz, 12db at 10hz, and tapering from the 20hz difference to the midbass freqs roughly, I knew the bass sounded fuller with the digital input, this would go someway to explaining the difference in the bass end of the spectrum