Pebble smart watch degrades Bluetooth audio quality?
Sonorous
F@H Fanatic US Icrontian
The back story. I purchased a Pebble Steel a few weeks ago and I love it. Except I think I have discovered a limitation of Bluetooth. After setting up the Pebble I went to Best Buy to get a screen protector for it, and on the way I knoticed the sound quality of music in my car wasn't the same as when I went to work earlier that day. Normally I stream music to my Mazda from my S4 via Bluetooth. It has always served it's purpose and sounded surprisingly good, but with the Pebble connected as well there is a noticeable "crunch" or distortion to cymbals and overdriven guitars. So I thought it was just a setting in the Google Play music app and I double checked everything was set to high quality while streaming over LTE. After confirming the settings were correct I chalked the issue up to an update from Google and dealt with it.
Fast forward to Saturday. I just bought a UE Mini Boom Bluetooth speaker. Upon a first listen I knoticed the same sound quality issues as I have in the Mazda, distortion in some of the high frequency. The following Monday I went to work but left my Pebble at home by accident. I was showing my boss the Mini Boom and to my surprise the distortion was gone! Peculiar. So when I got home I did some testing. When the S4 is connected to both devices the sound quality suffers. When it's only doing audio it sounds much better. To the common listener it may not be a big deal, but for someone who is in the sound reinforcement industry it drives me nuts. Has anyone ever had something similar to this happen? I plan on testing get with a few tablets and old phones I have laying around to dismiss the S4 as the only culprit, but others experience and expertise would be helpful.
Comments
It sounds like BT isn't properly shielded from the audio ICs.
If that is the case, why does music sound better via BT when the Pebble is not connected? I see what you are getting at, but I would think if that were the case it would sound the same regardless of what is connected. Could it be a bandwidth issue?
Power to BT is higher when multiple devices are connected?
I've spent about 4 hours researching what the issue is. I'll try some different devices and also see if i can get a recording of audio quality and report on it later. Just wanted to pick some brains.
It's possible. What Bluetooth version is supported on these various devices?
Pebble does have a lower-end BT profile, if I recall correctly, since things like the enhanced audio functionality aren't necessary for a watch... perhaps that forces the entire device to use the lower profile. I can't say I've noticed it with my Jaybirds, though perhaps I've not been paying too close attention to it.
Here are all the supported BT audio specs for the devices that I can find. I'm thinking I might try to create an Automateit profile that disconnects the pebble when the car or Mini Boom are detected. Not ideal, but it's an option.
S4: BT 4.0: A2DP, AVRCP, HFP
UE Mini Boom: BT 2.1, A2DP and HFP 1.5
2010 Mazda 6 (No navi): A2DP v1.0 and AVRCP v1.0 (can't really find a BT version. I'm guessing 2.1)
Pebble Steel: BT 4.0
Couldn't it just be a bandwidth usage issue?
I think midga could be on to something. It shouldn't be interference, but you could test that by connecting some other Bluetooth audio source to the car/boombox while your phone is connected to the Pebble.
Are you, by chance, running CyanogenMod on your phone? I've been having all sorts of BT issues with CM lately, it seems to be related to some tweaks they do to their kernel. You might try loading an alternate kernel (if you're running CM) to see if that helps the issue.
I've been doing some cursory research on Bluetooth bandwidth (shockingly hard to find). Apparently BT2.1 bandwidth is 3Mbps. Even if we were to assume that a BT host device degrades connections to peers to that of the oldest connected BT profile, then plenty of bandwidth still remains for two audio streams.
I just got some LG Tone+ BT headphones, and I've noticed the sound quality is kinda...sub-par. Come to find out, the O+O doesn't support aptX. Dunno that codecs would have anything to do with your issues, though. Just has me a little miffed.
I have had an unreasonably difficult time finding any information on BT other than versions and what acronyms mean. I'm glad I am not the only person.
I am unfortunately running stock 4.4.2 on my VzW S4. Last time I checked CM wasn't supported on my device.
The girlfriend just had surgery, so for now my testing is put on hold. At the very least I am gaining some knowledge in an area I did not know much about.
Not many phones support AptX in general. Rare.