There's a (surmountable) bandwidth issue with Bluetooth

I'm in the market for a bluetooth headset that I can use with the top down. A friend recommends Plantronics highly. I'd thought I'd have to go for the heavy-duty noise cancelling capabilties of the Voyager Legend, but my friend says the cheaper and sleeker M165 will be fine. Any thoughts? The Legend is more expensive and will make me look like a telemarketer, but if I really need the noise-cancellation of the Legend, I'll go with that and tell myself I look like a special ops guy on .HOMƎLAND.

2001 Base, purchased in 2004, replaced engine at 130K+, RIP 2017

They are much, much better. I use an over-the-head plantronics or a the similar Panasonic, with adapter for Iphone.

That said, i understand most people only want BT. I cant speak to the latest crop, i gave up on them long ago.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 10/09/2014 06:08PM by grant. (view changes)

I didn't even think of a wired one. Why are they better and which model do you use?

Bluetooth is low power, narrow band radio, with all the possible distortions. Wires sound much better ( assuming the connections are good, which is always suspect). try one and you'll appreciate the difference. Also true boom-mic headphones, whether wired or BT are much better at picking up your voice - of course this is not a function of the transmission technology, but it is more common on old-fashioned phone headsets.

As noted, i have several - one is a plantronics, about $40, that you can get from a verizon wireless store (or your brands no doubt). It may require an adapter for some phones.

[www.amazon.com]

I have also used a pretty good panasonic unit that's about $15 that i get on amazon.

[www.amazon.com]

note: both require an adapter for iPhones. The adapters range from pretty good to AWFUL. Its sometimes hard to tell the difference. Can be a PITA to sort out. If need be, PM or email me and I'll dig into my archives to tell you which one to get - maybe in a real store you can get quality without the hassle.

i also use them for conf calls on my cordless phones.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Great, thanks. I may go for Bluetooth so I don't have to fool around with plugging it in if the phone rings while I'm driving.

.. on both reception ( easy) and transmit (hard), let me know.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

With Bluetooth audio input, the bandwidth used is very narrow (typically 8 kHz). This translates into lower audio quality since they achieve such low bandwidth by cutting out parts of the audio, most noticeably the high frequencies.

If you can get a Bluetooth microphone that supports 16 kHz (sometimes badged as "wideband speech", "wideband audio"* or "HD voice") and has good quality components then the sound quality will effectively rival that of a wired connection. But 99.9% of of all Bluetooth microphones don't. And of course your phone has to support this too but most do.

Interference is basically a non-issue. Bluetooth is a lossless data transfer protocol. Though theoretically interference could reduce the effective bandwidth, that is not a problem in practice in this sort of application.

--

* Note that "wideband audio" is also sometimes used to describe the voice connection with the carrier, which is not relevant for this discussion.



Edited 1 time(s). Last edit at 10/12/2014 09:09AM by Boxsterra. (view changes)

First of all, in reality, there is no such thing as lossless transmission. In any protocol you have the choice, under compromise, of resend or drop data. There is no third alternative. Well, there is, int he form of redundant data coded in, but it too can be lost.

The bandwidth limitation is unlikely to be an issue. Landlines, at least pre-VoIP are just under 4khz and sound vastly better than any of these things. So that's a red herring. Having sat on MPEG and JPEG back when the earth's crust cooled, i can attest to the near magical quality of compression, especially for relativly simple things like voice where it can be characterized relatively well before one sets off to design a codec.

You have many,many points for fidelity loss - from the radio medium itself (loss, delay) to the ADC & DAC to the tiny little amplifiers they require. Its far more complex than simply sending an analog signal down a 3 foot wire, where the major issue is connectors and shielding.

And the results are just so obvious.

But in any event, the 8khz thing is so irrelevant. Its twice the bandwidth of the old gold standard. Hardly the limiting factor.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

I'm not sure bandwidth would be an issue -- I'm talking here about phone calls while driving rather than music. I think the biggest issue for me is wired or wireless in terms of convenienc0e and that may boil down too whether I want to fumble around connecting a device when I'm driving.

Further, though, my questions and was, assuming I buy a BT device to use with the top down, do I need to pay extra for the Plantronics boom models with supposedly outstanding noise cancellation or can I go for the cheaper models?

.. like the jawbone, with lousy audio quality ( agree with Bruce here).

But top-down in a boxster will be a major challenge.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

If you are gleaning this information from a quick Google search, I can see why you got it wrong. That is an often misquoted statistic. The telephone standard had limitations on how frequencies above 4 kHz were filtered using analog equipment. Aside from being obsolete, that is a totally different thing than 4kHz bandwidth, which is a frequency range.

I worked in audio signalling technology for many years.

And as I said above, the bandwidth isn't the only factor. The quality of the data is not the only factor; the quality of the analog portion of the equipment also matters, as does the digital compression technology.

... or how it helps people select a BT headset and understand where the exogenous limitations are.

Suffice it to say i've work those standards - and written some of them (as, btw, i already noted, above) - for > 30 years.

And the fact remains: the links that the mobile device will connect through - in the back-haul, in the core and in MSC fabrics, is typically < 4 khz and despite newer technology mostly remains that way. And most landline phone - whether analog, ISDN or VoIP, similarly connect to coders or transcoders that land them in the least-common-denominator of telecoms - the 8bit, 8kHz sampled (e.g.: 3400 Hz audio) DS-0 channel. So i am very, very right.

Maybe you need to explain how your audio bandwidth statement is different from the usual interpretation of same. Maybe you mean "radio spectrum allocated to carrying the audio signal?". Just a guess - and a note that that is not what you wrote.

interestingly we seem to agree that its unlikely to be the bandwidth that's the cause. As you wrote: "The quality of the data is not the only factor; the quality of the analog portion of the equipment also matters" Which is also what i said. So, i re-iterate - the audio bandwidth is a red herring.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

You're comparing apples and oranges The landline uses analog signals, while the cell phone (and Bluetooth) use digital. So a comparison of bandwidth between the two is meaningless.

This conversation is about Bluetooth versus wired cell phones, with an irrelevant diversion into landline technology.

---

It all boils down to two things:
- Cell phones transmit audio data at a higher rate than standard -- "narrowband" -- Bluetooth microphones
- Voice quality of "wideband" Bluetooth (with a sample rate of 16 kHz) is necessarily better than "narrowband" Bluetooth (8 kHz), which must discard valuable audio information (16 kHz sample rate provides for enough bandwidth to capture all of the frequencies of human speech, 8 kHz does not).

Therefore...

If you get a wideband Bluetooth earphone, the sound quality will be noticeably better than an equal quality 8 kHz one.

If you go further and get an earphone with higher quality components, that will also improve the sound quality but not nearly as much.

I even spent over $100 a couple times....... all crap. The biggest ripoffs were the Jawbones.... I owned two of these pieces of crap. Jawbones are marketing driven by people who know how stupid consumers are when it comes to buying.... stupid consumer will always buy something that is cooler than another perfectly good item. The worst thing about Jawbones is the sales people like them.... I would tell them of my bad experience with the last one (that they raved about) and they would say "Oh yeah, that was a bad one but this is better....". Funny how they are bad the next year and the new one is "fixed".

One big stupid lie is noise cancellation. Sounds like you need that eh? The biggest issue for me is people understanding me! I would wreck conference calls. When I couldn't hear others, it was because the unit didn't fit properly in my goofy ears or were simply not good sounding.

Other issues that make these units crap is the usb plug goes in at an odd angle. With the Plantronics, it goes straight in, aligned with the straight design of the unit. This makes plugging it in very easy to do without looking. You are driving, remember? The last Motorola I tried would slip out of my hand and drop behind my gas pedal... because it was so shiny cool.

The Plantronics on/off is a slide switch on the side and shows green when it is in the ON position. The talk/hang up button is directly over the speaker so you push directly down on your ear.... not to the side or off angle which changes the good position of the unit in your ear. Plantronics has it down. $24.

But Grant is right.... wired is way better. Always was. I keep threatening to ditch bluetooth but I don't like stowing the wires and I finally found this cheap, good Plantronics that does the job.

By the way, best I ever had does not mean it is fantastic..... just barely acceptable and better than crap... but not much more than that.

Peace
Bruce in Philly



Edited 1 time(s). Last edit at 10/10/2014 08:06PM by Bruce In Philly (2000 S Boxster, now '09 C2S). (view changes)