This whole topic is very interesting to me. Very ironically, just before this topic got started, I was thinking about qrp hall of famer, Rick Littlefield's, Ham Radio magazine article Mar 89', featuring a resonant cw speaker. It was built using a solo 16 cup and a small 700hz transducer. I put it on my to do list, back in 89'... nearly 28 years later I FINALLY sent Rick an email asking if he still had any of these little speakers left, after so many years... A few days later I had a package from Rick with a couple of the little speakers! The generosity of old school hams never ceases to amaze me.
I have a question for those in the "know"-- Knowing very little about the physics of sound, does using a thinner tube as opposed to a larger diameter one, make the tube have a narrower " bandwidth " ? How would on increase the Q of the device ( if that's even possible)? I'd appreciate any input. TIA 72 Dean/K2WW On Feb 18, 2017 8:09 AM, "jrquark" <[email protected]> wrote: > The confusion here is a common one, closed vs open ended resonators, > especially if one looks at the poorly explained graphs in most physics > texts. > > The speaker, attached to one end of the pipe, is not the closed end, it is > open, since it drives the air particles at that end, and that makes it a > displacement antinode, where the particle displacement is maximum. > > Jim - K7BIE > > > > On Feb 17, 2017, at 9:43 PM, Joe Subich, W4TV <[email protected]> wrote: > > > > A cylinder with a speaker in one end and open in the other is an "open" > > cylinder (open pipe). It is a *half wave* in air which means the > > formula uses 2f instead of f. > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
