Wireless Music System for PC - General Discussion

[crunchochango]

The signal I get on the receiver is absolutely horrible, and it only gets progressively worse the longer I use it, making it completely unusable after 15 minutes of play. I've tried both with and without th pc-extension base, both have provided equally dismal results. Distance is not an issue, as it isn't more than 20 feet from my computer with no wall in between. Any way for me to improve this?

[Andreasvb]

I have the same problem. I read in the manual that it uses Bluetooth 1.2, which is restricted to 723.1 kbit/s transmission(Wave in 44100 Hz is like 1411 kbit > 1.38 Mbit. In Vista it says it uses 16bit, 48000 Hz (DVD Quality). That should be more than 723.1 bkit/s that this product supports. Bluetooth 2.0 supports up to 2 Mbit/s, which should be a lot better for this product, like Logitech themself says

"Logitech is the first to introduce desktops with Bluetooth® 2.0 Enhanced Data Rate (EDR), enabling wireless audio with virtually no interference from other devices. For optimal results, use a headphone with Bluetooth 2.0 EDR."

They should've thought of this before even attempting to release this. Alternatively using an encoder like AAC/MP3 and send it in 320 kbit/s, which is less than the max speed of 723.1 kbit/s.

Would like to hear Logitech's response to this.

Thanks,

Regards Andreas

[crunchochango]

Ok, if I understand what you are saying correctly, this is a problem that should only affect high quality signals, such as DVDs and wave files, correct? Thus far I have only been trying to transmit MP3s of no higher quality than 256kbps, though maybe it's conceivable that some of the variable bit rate mp3s could spike higher than the limit. Also, I'm using XP, so I don't know if that makes a difference. Thanks for the help nonetheless,
Karsten

[Andreasvb]

I don't know if it keeps the bitrate, let say 192 kbps MP3, or if it sends it decoded back to wave or something.

Would be great if someone could enlighten us on that.

[beetee]

I had terrible static - went into control panel/settings/audio/ and pulled wave setting way down. Not all the way or you shut it down, but way down. Something easy to try and it worked for me for whatever the reason ... I use a Creative x-Fi sound card with a set-up at the computer and for some reason when I unplug the logitech transmitter and reset itunes the settings all reset.

[Andreasvb]

Right now I'm using Vista and with kX Project(alternative sound driver), but Logitech uses its own driver with Wireless Music System for PC, and there's no slider in Vista to disable accelleration.

I've also tried it in Windows XP and turned the slider down, same thing. I've even tried on another computer, no go. The music gets really terrible after a while. I'll record it and upload it somewhere so you can hear it.

[Andreasvb]

Ok, this is the recording I did, listen closely at about 3:00

http://dwi.mine.nu/TerribleReception.wma

I believe it's something wrong with my device, should I call Tech Support?

[BrettVerseso]

Andreas,

I don't know about Logitech's response, but you are confusing a few things. Windows audio systems delivers audio (all PCM) to USB devices at the bitrate negotiated / defined by the USB audio device. All bitrates and encoders on the application side are not relevant. The USB device will be delivered an audio stream based on it's own needs.

Additionally, your assumptions for bandwidth demand are incorrect. As with all A2DP Bluetooth devices, the audio stream is delivered through a compressed (and lossy) CODEC. The primary CODEC used for A2DP is SBC (others are occasionally used, but this is rare.) The bandwidth for a high bitrate SBC is substantially less than that for uncompressed PCM streams, and is well within the available bandwidth of BLuetooth 1.2.

One of the biggest issues with A2DP audio is the availble bandwidth within the 2.4 GHz spectrum. BT 1.2 utilizes Adaptive Frequenct Hopping (AFH), which will essentially turn off some of the available channels that are overlaping other devices in the area. That works great if there is a single interferer, like a single WiFi network. But if there is more than that, AFH doesn't work as well, because it can't turn off all of the 79 channels, only around 20. So if you have WiFi in your house, and also have a 2.4 GHz phone, or your neighbor has that... well, too bad. Your AFH probably is taking care of your WiFi network, but when your phone is in use, it is using even more of the 2.4 GHz space, and there is no where else for your BT device to work in. (Cordless phones, microwaves, WiFi, etc., are ALL more powerfull that Bluetooth.) In this David vs. Golaith deathmatch, David doesn't stand a chance!

BT 2.0 + EDR is a little better, as the faster datarates will allow more re-transmits, hopefully getting the audio data in the buffer before it turns the data into sound and squirts it into your ear, but agility will not always win the war. If the 2.4 GHz spectrum is overrun with more powerful devices your audio will be comprimised.

As with everything, your milage may vary.

-Brett

[tomtomgoer]

Brett, at the risk of sounding patronising....great explanation for a complicated issue. I have replied in the Wireless Music DJ forum to someone who is concerned about drop out, and your explanation will no doubt be useful to them. Might be worth reposting this there.

[Andreasvb]

Hi.

I wrote here some time ago, also having this same dropout/stuttering issue.

Unfortunately nothing of these "suggestions" works, it's just POS hardware(atleast the USB transmitter), sorry.

Some days ago my dad bought a new cellphone and a BT adapter, HAMA AD2P, but anyone of these should work: http://www.a2dp.info/A2DP-Devices/A2DP-Transmitters/Adapters.html

Today, just for fun I tried to connect the WMS for PC to the BT adapter, found out the pair code was 0000, connected nice and was discovered as Logitech STR01 and connected with Bluetooth Advanced Audio Service.

Have now been playing music with foobar2000 with output DS : Speakers (Bluetooth AV Audio) for over 3 hours and no dropouts/stuttering whatsoever.

I recommend you get a BT adapter and trash the one that comes from Logitech cause it literally blows.

Good Luck all!

Message Edited by Andreasvb on 06-19-2008 11:00 PM

Message Edited by Andreasvb on 06-20-2008 12:10 AM