The 3 Main Issues That Arise with In-Car PC Bluetooth Handsfree

[Nola111]

I just wanted to throw this out there as a reference in hopes of helping some folks. I've extensively tested 3 PC BT solutions now, and I just wanted to share some of my experiences.

Here are the 3 main issues that people (including me) have run into when using any PC-based BT handsfree solution, and current known solutions.

1. Noise - by this I mean that the person on the other end of the call complains of the background noise of the car and the road is so loud that it's hard to hear or understand the person in the car talking. There are several noise-canceling mics that you can buy that will help remedy this. They will greatly reduce the road and background noise going into the mic, and make the person on the other end of the line less likely to hang up on you. This is the easiest issue to remedy of the three.

2. Echo - echo can affect both parties on the call, or just one. The main complaint you'll hear is again from the person on the other end of the call, who says they can hear themselves echoing back through the line after they've spoken. This is caused by the microphone you're using picking up the sound from the speakers. One of the solutions for this is a half-duplex approach, which can be present in either hardware or software. In simplest ways of putting it, the microphone mutes itself when you're not talking into it. This prevents the speaker output from entering the microphone. The shortcoming of this is that half-duplex is basically what you're doing when talking on walkie-talkies. It can be frustrating at times when being used to full-duplex conversations on a telephone. Some USB mics used mainly for business teleconferencing have built-in echo cancellation, but as soon as you introduce a USB mic into the mix, you face issue #3...

3. Audio latency (delay) - There is a delay, anywhere from a second to 3 or 4, between when you talk and when the other person actually hears you, and vice-versa when they talk to you. This is by far the most annoying issue to deal with when trying to hold a conversation. My wife refused to talk to me on my former handsfree system until I remedied this. The latency is caused by Windows' simultaneous handling of two soundcards. I mentioned the USB mic above... as soon as you introduce a USB mic to the mix, you're introducing a new soundcard. In this case, you have to use the USB mic as your recording soundcard, and your normal soundcard for your speakers as your playback soundcard. Using the same sound card for your speakers and your mic is one way to reduce latency to almost nothing... the bad news is though that most noise-canceling and echo-canceling mics are USB mics. They have to be since they require more power to perform their functions than the very small amount of power that regular 1/8" or 1/4" analog mic jacks put out. So this causes a bit of a conundrum... How do we solve 1 and 2 w/o creating 3? Most OEM BT solutions coming out in cars these days handle 1,2, and 3 by having all the hardware and firmware as one integrated system (not to mention that the system doesn't have to process other PC activities!). The mics they install in the cars have noise-canceling and echo-canceling technology built-in (with plenty of power to draw from the audio system), and the latency is not present because it's all tied in to the same audio system (as though on the same "soundcard" so to speak).

There is a hardware solution out there that works to reduce all three issues. It's called the Phoenix Audio SOHO. A couple associates of mine report great success with it. The only downside is that it requires a PCI slot, which a lot of car pc users don't have.

So that's that. Hope it helps people understand as they run into these issues. I'm raising my happy hour glass now... here's to David, Scott, et al finally cracking the code in Windows to be able to kill all three of those nasty issues above for us Centrafuse lovers, regardless of our systems and hardware. The "other pc solution" of which I was a private beta tester was not able to accomplish it before they went completely south and gave up. I have a feeling that our boys will be able to do it.

[deltabi]

Thanks, Nola for your in-depth report about the topic.

One of the reason why I waited for CF2.0 was bluetooth integration (I was never able to use Phoco module...).

Now I'm starting to think (and you are confirming this) that, actually, an handfree kit based on a Bluetooth stick and Windows (CF or what else) is hardly giving what everybody looks for: a usable solution for safe, in-car phone conversations.

After all the readings and my own tests on the subject, I'm leaning toward an OEM solution (Parrot CK3000) because I don't see any useful development in this particular area...

Can Fluxmedia confirm what kind of conversation quality they got when testing the new bluetooth integration software module? Can this solution provide the needed quality for true handsfree in-car phone usage?

Thanks a lot for your comments.

[Nola111]

I agree that right now the dedicated kits and OEM offerings are the best working solutions, but I want to be very clear that this has nothing to do with the shortcomings of the Centrafuse program. As can be seen in my post, it's a combination of hardware and Windows that lend to the problems.

I don't want to undermine David and Scott's hard work thus far, so definitely note that I'm not saying anything against CF at all in this regard. It really comes down to all the different pieces of hardware we're all using.

Also check out Scott's post over at mp3car where he talks a little more about echo and that they're looking into finding any possible solution in the future...

http://www.mp3car.com/vbulletin/1208528-post21.html

[deltabi]

Originally Posted by Nola111

...I don't want to undermine David and Scott's hard work thus far, so definitely note that I'm not saying anything against CF at all in this regard. ...

Neither am I! It's pretty clear to everyone that the problems comes from Windows architecture and the hardware involved.

This is why I wanted to hear from them (Fluxmedia) because I suppose they had a chance to see by themself what are the performance and the quality level of a carpc-based handsfree phone solution.

I'm just trying to understand if there is a possibility of getting a high quality handsfree solution with a CarPc and Centrafuse.

(BTW I think CF is a good product and this is way I've already bought an XLE )

[Scott]

Everything Nola mentions is pretty much truth, Windows, unknown bluetooth hardware, unknown audio hardware, you'll never find a Windows solution that matches the quality, as far as sound, of an OEM car kit. It's just not possible. The ONLY way to get an OEM quality bluetooth solution on a PC is to use bluetooth over UART protocol, and route SCO data to a voice codec, in turn which can be connected to a hard line in on the pc. Obviously, there are no solutions out there that utilize this, it's all SCO over USB, so think about that too. Synchronous voice data, being transferred over an asynchronous bus such as USB. Not ideal if you want "voice quality". With that said, BLuesoleil has done a good job with what's already there, and I believe that when we can add a software based echo cancellation processing algorithm to mic data in Centrafuse, that it will be more than useable, we will be wroking out these issues over the next several months and throughout summer/fall...

[deltabi]

Smeesseman,

Thank you for your honest reply. You cleared it up pretty much.
Keep up the nice work on CF.

Diego.-

[Nola111]

And in the meantime let's not forget that it's still a completely useable feature. Every morning on my way to the office I check my office voicemail through CF over my speakers.

[mac90]

been thinking about the the item listed in the post by Nola111, particularly the echo.

I have no idea how possible or feasible or indeed how cpu intensive this would be but.....

If you took the line out signal (ie the sound send to speakers) when in a call invert the soundwave, possibly add a small configurable delay and merge this back with the mic input, the speaker output picked up by the mic would be virtually cancelled out by the inverted signal eliminating the echo.
Just a thought

[Greenthumb]

We allready discussed this in another thread, but to me it would be perfect if we could use CF to control the phone, like choose a number, see who's calling, etc, and when a connection (phonecall) is being made, the carkit will take over.
This way you have a device built for the function to make the calls, and you have the handy-ness of a carputer for controlling the phone.
I believe this was possible with phone-control, so maybe some tips could be given by it's creator to the CF-team .

[Scott]

Originally Posted by mac90

been thinking about the the item listed in the post by Nola111, particularly the echo.

I have no idea how possible or feasible or indeed how cpu intensive this would be but.....

If you took the line out signal (ie the sound send to speakers) when in a call invert the soundwave, possibly add a small configurable delay and merge this back with the mic input, the speaker output picked up by the mic would be virtually cancelled out by the inverted signal eliminating the echo.
Just a thought

That's called software EC, and companies have spent years developing this technology. It's not quite that simple.