Difference (if any) btw BT or wired audio from iPhone

Apr 20, 2022 | 12:31 PM

E63Wagen

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2020 E63S Wagon, 2007 335i convertible (tuned to 400hp), 2011 Audi A4 Avant

Difference (if any) btw BT or wired audio from iPhone

OK, so I've been playing around with listening to music in the car from Amazon Music service, both wired and through Bluetooth via my iPhone. Here are some specifics:

iPhone is 12 Pro Max, with BT 5.0
Amazon music service outputs audio in several different "qualities", depending on content. Sometimes it's "HD" sometimes "Ultra HD", and sometimes even "Ultra HD Atmos". I believe HD is equivalent to CD quality (44/16)
I have a wagon, so it's the standard Burmester system
I also have an SD card loaded with all lossless FLAC files, as I care about the best audio quality possible

Anyway, I have been listening to Amazon Music (multiple qualities) both wired directly and through Bluetooth. I believe I hear slightly better quality when it's wired, but not sure as my old ears (and head) might be playing tricks on me. I am hoping someone with better technical audio knowledge that I have can comment on whether wired actually DOES provide better quality than BT. And would either ever approach the quality achieved by listening to FLAC files on the SD card?

Comments?

Last edited by E63Wagen; Apr 20, 2022 at 12:34 PM.

Apr 20, 2022 | 12:47 PM

E634Me

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2018 E63S AMG

If both delivery methods use the same source audio encoding standard and data rate, then the resulting audio quality should be the same regardless of transmission method (wired or BT) unless there are bit errors in the transmission of one delivery medium or the other. Wired should be error free, BT could have some drop outs occasionally that would be audible but if that's not happening the quality should be the same.

Years ago I worked for a company that did satellite communications and PBS was one of our customers. We wanted to switch the transmission of their programming from C band satellites to Ku band satellites. There was no change in the audio modulation used to transmit the signal, just a change in frequency. Nonetheless the golden ears at PBS were sure the audio quality suffered as a result of the change. Us engineers assured them that there was no difference at all in the audio and provided some qualitative measurements on THD and other tests but they were unconvinced.

Finally, they agreed to double blind testing. Result? The golden ears were totally unable to tell which transmission path was being used C band or Ku band and the issue was finally settled.

Apr 20, 2022 | 01:24 PM

superswiss

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BT will always be worse, because BT audio is lossy where as wired is lossless. BT just doesn't have the bandwidth so all audio transmissions over BT are compressed on top of the source compression. The BT codecs have been getting better, but they are still lossy.

Apr 20, 2022 | 02:08 PM

E63Wagen

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2020 E63S Wagon, 2007 335i convertible (tuned to 400hp), 2011 Audi A4 Avant

Sounds like E634Me and Superswiss disagree...

Apr 20, 2022 | 02:26 PM

superswiss

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I forgot about aptX Lossless, which is a recent codec improvement that does compression w/o throwing stuff away, but it uses WiFi in addition to BT. Don't know if MB supports it, though, and of course the device you are using has to support it, too. Ultimately, the BT streaming quality depends on the radio environment. With a lot of interference around you and less than optimal placing of the phone inside of the car, the bitrate can drop quite low. Satellite communication on dedicated frequencies is a very different story compared to BT which shares the 2.4 Ghz band with WiFi, microwaves etc.

https://www.androidauthority.com/los...audio-2740550/

Last edited by superswiss; Apr 20, 2022 at 02:33 PM.

Apr 21, 2022 | 01:34 PM

raudiace4

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19 E63s, 23 M3 compX, B9 SQ5

I have the Burmiester 3D system, and it is fantastic you can really hear instruments that you didn't notice before on subpar audio systems. I usually always use bluetooth, but if you ever use USB media input or wired media (ipod iphone) the sound quality is slightly better.

In layman's terms, bluetooth has audio signal limits that affect sound quality that wired sources simply do not.

Apr 21, 2022 | 06:56 PM

Cylinder Head

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I've used both and there is absolutely a difference with the wired audio. All of my files are lossless and they sound perfect when wired with the 3D system, less than perfect with BT.