heart rate monitors synching w/computer

[Will-i-am]

My wife recently had some tests run and found that her heart numbers are not good and have been getting worse. So we bought a heart rate monitor and we exercise and eat very well. She's lost 2 out of 4 sisters to heart problems and a third had quadruple bypass surgery last year! The heart rate monitor has a chest strap that broadcasts to a wrist display and there is a thing in the manual about transferring settings from the computer to the monitor if the computer has dynamic loudspeakers. It is not explained how the loudspeakers do this. Anybody know about this? There's no auditory function to the monitor except for the 'beep' noise it makes, so I figure it might be the actual magnetic field from the dynamic speakers (as opposed to some other kind of speakers?) There's a neat trick to try to explain!

[Oliver]

You got me curious here.  I had a quick look around the web, and it seems that 'dynamic speakers' are just plain or garden variety, permanent magnet/electromagnetic voicecoil speakers.  The other main type of speaker used in audio reproduction is an electrostatic speaker.  I personally think the term 'dynamic speaker' is daft, but then they didn't ask me when they made it.  There is another type of magnetic speaker, which uses opposing electomagnetic fields, but these are uncommon today.  There are also other types of speakers, but they are not really worth a mention.

I believe the wrist watch communicates to the monitor via magnetic field transmission.  The wrist watch should be able to receive a signal from a speaker in a similar fashion.  I suspect the monitor comes with PC software, which your doctor probably neglected to issue to you.  I had a look at an apparrently similar product here.

[Will-i-am]

Thanks much for the quick response. I trolled around the web a bit, trying to get some technical information about the transfer. Yes, there is software required and you download it from Polar's site. I agree that logically it must be magnetic as they tell you to hold the wrist monitor near the speakers. That's so strange though that they don't seem to tell you anything about how it works. I guess most people don't really care but my wife is an Ultra-Geek who requires a lot of information and she set me the task of looking it up. I'm not even sure if the speakers we use here are 'dynamic' or not. They did say on the Polar site that some speakers were piezo so I suppose they need the old fashioned kind with the big coils or something. I'll continue to explore the web. Thanks again.

[Oliver]

Most speakers use magnetic fields.  Tweaters may be piezoelectric, but not likely a woofer.

Magnetic antennae are usually just based on a conductive loop, using inductive pickup.  There are other ways to detect fields, though I guess it's just the inductive loop.

I would think that explaining technology doesn't usually help any marketing efforts, so they wouldn't bother.  It might just frighten some people to think of these fields within close proximity.

Hope the heart gets better.  Life's too precious.