Hiccups in Bluetooth audio output

I experience this as well, although what grates on my nerves more is when the audio drops out for a second, and is then followed by the song running at a higher pitch (slightly faster to catch up). I use a Bluetooth mouse, and the issue is caused by allowing the mouse to idle for a bit and then attempting to move it. If I move it very gradually and then use it normally, the drop doesn't usually occur. If I jerk the mouse, the audio will drop out. If I attempt to sync my phone over Bluetooth the audio also gets flakey. (Macbook Pro, Motorola HT820's, Dell Bluetooth mouse, and a Nokia N76 - the problem isn't with any of these devices, but seemingly with how Apple's BT stack handles multiple connections.)

In 10.5.1 the problem was far worse. Moving the mouse at all would cause the audio to frequently drop out. I'm incredibly happy that Apple made some massive improvements in 10.5.2, and I'm really hoping that it'll be 100% fixed in 10.5.3. In order to ensure that happens, please take the time to give Apple feedback about your Bluetooth experiences and issues.

If you're using a Macbook Pro, the feedback form is here:
http://www.apple.com/feedback/macbookpro.html

If you use a Macbook, the feedback form is here:
http://www.apple.com/feedback/macbook.html

If you're using another Apple system, please use Google to search for your product name and "feedback" (throw in a site:apple.com to make it really easy) to find the feedback form. I've heard from Apple people that issues have a better chance of receiving higher priority if more customers remark on them. Please don't spam their forms and please be polite about it, but do let Apple know that the issue isn't fully solved.

It definitely sounds like a buffer under-run to me. I observe the same symptoms on my friends mac mini. If you leave the system alone (no background downloads/uploads) no disk activity, just iTunes streaming to the Bluetooth A2DP headphones, everything works like a charm. But as soon as I do anything (disk access, open document, browse the web or simply launch an app) then the "dzzt" start mangeling itself with the audio stream. Actually, I notice a bend in the pitch of the music before it happens (as when a 45 was slowed down to 33 for those who played with LPs)... very disturbing. It sounds like the BT stack is trying to avoind interruptions by slowing down the sampling and eventually falls behind giving birth to the "dzzts" you mention.

I'm still looking through plists to see if there's a buffer size somewhere, next I want to try to increase the priority of the BTserver but that could be dangerous. I googled everywhere, with not much luck. I can't believe we're the only two complaining about this.

Now I understand why the iPhone/iPod do not support A2DP. If Apple's BT stack can't keep up on a 1.6+GHz Core Solo... imagine that on the iPhone's little ARM.

😟

If anybody finds a trick to make it work, let us hear about it!

Are you referring starting the HT820 up and using it with the system? I've noticed something similar - I get a lot of "Bluetooth audio connection failed" messages (to which the options are "ignore" and "stop using device") before I start getting audio. I think it has to do with trying to use audio too quickly after telling the computer to use the device as headphones. Consider that it takes your average Bluetooth headset ~5-7 seconds to match up to your phone and be usable with it. By waiting about that long between activating the HT820's as headphones and using audio I've received those messages a whole lot less.

I'd guess that it's an issue with the way Bluetooth works rather than something on Motorola's or Apple's end, but it'd certainly be nice if it were a bit quicker.

i also found a correlation with the static and hard drive activity... when i'm listening i try not to do any hard drive intensive tasks... e.g. when i'm transcoding video is the worst... but just in general use it's very clear... can't complain.

also found that sometime it's making the sound.. i just click on "Don't Use Headphones" and then click on "Use Headphones" again and it works fine after that.

i'm using a MOTOROKR™ S9 with a belkin USB bluetooth adapter (with class 1 transmitter... 300ft range) and as long as i'm not doing anything too intensive it's great

For me, it seems to be more processor-related than HD-related. The Bluetooth Audio Manager consistently seems to use 3-8% of my processor usage (2.33 GHz Core 2 Duo system); if both cores are used above a certain amount (I'd imagine it's 50 or 60% but I haven't paid as much attention as I should) I notice a higher instance of blips in the audio and static. I guess it makes sense, although I wish that the Bluetooth Audio wouldn't take up so much processing power (among my many other wishes for Bluetooth audio - I'm sure we'll get there eventually).

+For me, it seems to be more processor-related than HD-related.+

wonder if it's a bit of both.. transcoding video is the worst for me of anything and is both HD and CPU intensive (Handbreak basically uses as much processor as is available... both CPUs pegged at ~100% when Handbreak is running)... but i also find that it happens when a time machine backup starts as well... which is not that CPU intensive.. but not as bad.

I too have problems with Bluetooth. I use a Motorola S9 with my Mini, and I'm having to tell the Mini 2-3 times to use it every time I want to listen, before it becomes active.

After that the sound is great for a while, but at irregular intervals the sound disappears only to reappear after 2-5 seconds. Moving the mouse seems to bring back the sound faster, but not consistent.

Since OSX is a true multitasking OS I am wondering if this is caused by another task interrupting Bluetooth. If so it may be possible to raise the priority of Bluetooth so it does not get interupted. Does anyone know how to do that?

On top of this problem I have experiensed music sounding like it came from a cassette tape that is dragging. (pitch/speed going up opr down). This when playing music from my iTunes library and listening via the S9. Anyone with similar problems with Bluetooth or iTunes?

Setting the priority of the processes "BluetoothAudioAgent" and "AVRCPAgent" to the highest possible value (by "sudo renice -20 processIDToBeSetToTheHighestPriority") solves the problem (I think!). At least I've been sending music to my hi-fi chain for more than half an hour without any shshshhshs 😀

No, actually I have never had any problem connecting the device, I only have the noise. Maybe you are also using at the same time a BT mouse or keyboard? It seems that this generates problems with A2DP devices...also!! 🙂

I've experienced the pitch bending problem with my Macbook paired with the Motorola S9 headphones, but I've also seen this with my Samsung T10 MP3 player. I'm wondering if this is a problem endemic with the Bluetooth standard itself, or possibly the headset I'm using? I'm not sure if I would prefer to have the odd "tape dragging" effect or a drop-out. Personally, I'd rather it just be CD-quality happiness like I expected. Thanks! (Subscribing to this thread.)

Ledgem,

Did you have any difficulty getting your Dell Bluetooth mouse to work with your Mac? I've read on Dell's website that a Bluetooth mouse I just ordered only works with some Dell systems, although I'm sure I can find a way for it to work with Mac. Any suggestions for getting the mouse to work with my new Macbook?

No difficulty at all, just use the Apple pairing wizard and tell it that you're pairing with a mouse. No special configuration necessary. You won't be able to make use of the Apple wireless mouse features (I think you can name the mouse and view the battery remaining), but the mouse works. I only have two complaints: 1) the tracking speed is a little bit fast, and it's only one notch to the right of "slow" in the mouse settings (setting it all the way to the left makes it -much- slower), and 2) the double-click speed always seems to reset itself to the slowest setting (causing me to have a lot of unintentional double clicks). I had the double click problem with a USB mouse as well, though, so I can't blame Dell or Bluetooth for that.

Not sure what model this Dell mouse is, but the part number is UN733.

I've the same problem, a very disgusting shshhshshs, sometimes very often (almost continuous), sometimes each 30 seconds. It is really annoying! I don't know what to do!

It doesn't pair with my Powerbook G4 all the time... seems to be something with response times: if I have a couple of programs open s.a. safari, mail, skype ... pairing doesn't work ... I then close the programs, open preferences/sound and click away from HT820 ... wait a couple of seconds untill the computer actually notices the change ... then select HT820 again ... then it gets paired. I cannot think of anything else as a time-out.

I did install : AudioGateway.app http://www.softick.com/bluetooth-audio ... not sure if this has anything to do with the fact that HT820 works (but you have to be disciplined and keep a usb headset nearby)