Audio quality differences between various connections

[MikeSoundTouch30III]

Hi, Bose,

I'd like to check with you my idea about audio quality of different connections between PC and SoundTouch in order to find out what connection to prefer, without taking into account a type of audio (mp3, stream, internet radio...) - just regarding transferring data from PC to SoundTouch with as much of the original amount of source data as possible (with the least compression, data loss or other interferences that can lower the sound quality - latency, analogue deficiencies etc.). Can you correct me and provide a more expert opinion (I'm not an audiophile and a very non-technical type)?

1) WIFI by incorporating iTunes'/Windows Media Player's Library into SoundTouch App - lossless, no compression, plays 100% of audio data from the PC source (right?)

2) 3,5mm AUX cable from PC's LINE OUT (not just speaker/headphones port) - analogue without compression, plays more-or-less 100% of audio data from the PC source, but depends on the quality of line-out PC port and cable - if not proper, might create analogue defects of sound (right?)

3-4) (here I am not sure, will let you decide, might also depend on a generation of Bluetooth device) BLUETOOTH 3.0/4.0/4.1 - compressed by SBC codec (shame it's not aptX, Bose should upgrade in the future), probably the greatest data loss, very high compression, even if it says 328 Kbps, sounds more like 128-160 Kbps mp3, not even taking into account occasional lags and other sound defects due to long distance or interferences between devices. Doesn't make much sense buying expensive Bose speakers in order to play music via Bluetooth...

3-4) 3,5mm AUX cable from PC's HEADPHONES PORT - analogue without compression, but due to horrible quality of most headphone ports might lose as much original sound data/quality as with connection through older Bluetooth (2.0 or less), not mentioning cracking and other audio defects related to a lower quality analogue transmission.

So

1. a) is this "table" right (only relating Bose, other producers might differ - use aptX codec or some top quality AUX)?
2. b) Does Bluetooth connection have generally lower audio data loss than AUX cable from a standard PC/smartphone's headphones port - who gets the bronze?
3. c) Are there any relevant audio transmission quality differences between various generations of Bluetooth - 2.0, 2.1, 3.0, 4.0, 4.1? If a PC have 3.0, does it make sense to use 4.0/4.1 USB Bluetooth adapter?

Please take time to answer, might also ask some professional technicians when you'll have lunch together in Bose canteen, so we can get a really expert opinion. I think it's pretty important to know about the quality of audio transmission, was surprised how many people don't question Bluetooth connection - but who would guess that before WiFi came, the best home audio connection was that of the 19th century (!) AUX cable... I also think that Bose should offer USB connection between it's speakers and audio source, it's good to have a WIFI digital quality without compression and analogue defects packed in an easy-to-use cable.

Thanks in advance

Michael

[Andy_B]

Hey MikeSoundTouch30III,

Thanks for your post - I'd be happy to answer some of your questions.

Your outlined staging to audio quality differentials between connection types looks relatively correct. I'd like to emphasize, however, that while we at Bose don't publish audio performance statistics from our speakers as this doesn't accurately reflect the actual performance or sound of the speakers. We like to think that our customers will be able to fully utilize and enjoy the speakers from any of our supported audio inputs, but we also have similar interests to most of the audiophiles out there! 

I'd also like to take a moment to also note that there are a huge number of variables that will come into play with enjoying audio from different connection types. While you're correct in stating auxiliary cables will send the analog signal - this can be affected by the physical hardware of the audio output port on the connected devices. I've personally seen and heard of using third-party auxiliary output ports on music source devices like personal computer's to transmit higher quality audio via the auxiliary line. 

You can find additional information on the lossless audio formats that are supported by Wi-Fi streaming for our SoundTouch enabled speakers, including their associated bitrate limitations from a post made by Joel HERE which you may find of some additional use. 

While we won't be able to provide any additional information - I do encourage our community to contribute their own thoughts and opinions on this thread. 

Kindest,

Andy B - Community Support