Hi Dave, http://www.webref.org/acoustics/h/helmholtz_resonator.htm and http://www.phys.unsw.edu.au/~jw/Helmholtz.html and http://www.sfu.ca/sonic-studio/handbook/Helmholtz_Resonator.html At 10:25 AM 3/22/2003 -0800, you wrote: >Thanks for the correct terminology. I don't know what the "Helmholz etc." >is. > >David I. > >----- Original Message ----- >From: "Don" <pianotuna@accesscomm.ca> >To: "College and University Technicians" <caut@ptg.org> >Sent: Saturday, March 22, 2003 11:35 AM >Subject: Re: Recital Hall Acoustics > > >> Hi, >> >> I think you mean 200 hertz not megahertz....unless your audience consists >> of "my favorite martian". What about Helmholtz resonators? They are >> tuneable to specific frequences so could be used like a "notch" filter. >> >> At 09:09 AM 3/22/2003 -0800, you wrote: >> >I went online to check on bass traps for my local community concert >venue. >> >I have a problem with the 200 mhz range. I'm wondering whether or not I >> >need to put these acoustic bass trap wedges in all four corners or just >> >behind the stage? Looks like around $50 for a 4 foot piece.... >> > >> >David I. >> >----- Original Message ----- >> >From: "James Ellis" <claviers@onemain.com> >> >To: <caut@ptg.org> >> >Sent: Saturday, March 22, 2003 7:55 AM >> >Subject: Recital Hall Acoustics >> > >> > >> >> Wim Blees certainly got the most for the money if his $500 worth of >> >carpet, >> >> wooden strips, and screws solved the problem. That's about what I >would >> >> expect an acoustical engineer to have charged for a one-time >evaluation. >> >> Charging $10,000 for an evaluation, in my opinion, is way out of line. >> >> After all, this is a recital hall, not the Cathedral of St. John the >> >Divine >> >> in New York City with its 200 x 600 ft. nave, and dome high enough to >> >> accommodate the Statue of Liberty. >> >> >> >> Carpet will work wonders for damping out the high frequencies, but it >will >> >> do little for the mid-range, and nothing for the low frequencies. In >> >Wim's >> >> case, it seems that damping the high-end frequencies was sufficient to >> >> solve the problem. >> >> >> >> I mentioned the commercially available panels to inform those facing >> >> similar problems that all sorts of options are available to them. For >> >> those who have had any experience in this area, common sense will tell >you >> >> what you need to do. Hard, flat, parallel side-walls, and hard curved >> >rear >> >> walls that bring reflected sound to a focus up in the seating area are >> >> killers. This is so obvious, and yet it happens all the time because >too >> >> many architects seem to know nothing about acoustics. >> >> >> >> Jim Ellis >> >> >> >> >> >> _______________________________________________ >> >> caut list info: https://www.moypiano.com/resources/#archives >> > >> >_______________________________________________ >> >caut list info: https://www.moypiano.com/resources/#archives >> > >> > >> >> Regards, >> Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. >> >> mailto:pianotuna@accesscomm.ca >> http://us.geocities.com/drpt1948/ >> >> 3004 Grant Rd. >> REGINA, SK >> S4S 5G7 >> 306-352-3620 or 1-888-29t-uner >> _______________________________________________ >> caut list info: https://www.moypiano.com/resources/#archives > >_______________________________________________ >caut list info: https://www.moypiano.com/resources/#archives > > Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. mailto:pianotuna@accesscomm.ca http://us.geocities.com/drpt1948/ 3004 Grant Rd. REGINA, SK S4S 5G7 306-352-3620 or 1-888-29t-uner
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