Members swilk Posted June 16, 2007 Members Share Posted June 16, 2007 I just started buying some PA equipment for playing recorded music at parties .... I have a pair of Yamaha BR15 speakers ..... when running higher volume for longer periods of time I periodically loose the "highs". Could the internal crossover be overheating? A complete inventory of what I have: Yamaha EMX512Yamaha BR15's(just added today) Peavey PV1500 The first couple of times I used the system it was just the EMX512 and the BR15's .... highs cut in and out. I bought the PV1500 today and played it for a while in my garage .... highs cut out after a while. Keep the volume at a reasonable level and it seems to be fine. Crank it and the highs periodically disappear. And .... I know, I know ..... the BR15's arent the greatest in the world. I bought a package system before I really researched anything. Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 16, 2007 Members Share Posted June 16, 2007 Could be a couple of things, IF they have shifted to a PTC device that may be opening to protect the tweeter, the VC of the tweeter may be getting warm and binding on the pole piece, could also be a high pass capacitor getting warm and opening up (not too likely). Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 I should have put this in my original post ...... I dont speak "audio technician" Could you please put what you just said in laymans terms? I guess I have 2 choices .... try and get the shop I bought the speakers from to fix them ..... or fix them myself. I was looking into buying a crossover for each cab to replace the factory internal unit. I am going on the 100% assumption that what is happening is happening in the speakers .... not the mixer. Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 Got to love google .... PTC ... precision tuned crossover? Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 17, 2007 Members Share Posted June 17, 2007 Look at speaker manufacturer's advertising... it's one of a couple of high frequency driver protection techniques called "Positive Temperature Coefficient" thermistor devices. As the device gets hot, it's resistance increases and the power to the horn decreases. They can become damaged. If you don't know what these are and how these protection devices work, I think you will find repairing a crossover with this kind of protection pretty tough. I do not recall if the BR series cabinets use this protection scheme. Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 Possibly the speaker is smarter than I give it credit for ..... Yamaha lists the BR15 as a 400/800 speaker. The EMX512 is something like 350W at 8 ohms. If ..... if .... I was playing the 512 load enough to clip slightly could it have heated something in the speaker up enough to "protect" itself. Bear with me ... Im learning here. The highs instantly come back when I turn the volume down and the continue to work when I turn the volume back up ......... the more I think about it it makes more sense that what I am experiencing is a protection feature of the crossover network. Link to comment Share on other sites More sharing options...
Members stvcmty Posted June 17, 2007 Members Share Posted June 17, 2007 from the pdf for the BR series: "Special NoticeProtective Circuit (poly switch)All full-range loudspeakers are fitted with a self-resetting poly switch that protects the high-frequency driver from damage caused by excessive power. If a loudspeakercabinet loses high-frequency output, immediately remove power from the unit and wait for two to three minutes. This should be long enough to allow the poly switch toreset. Reapply power and check the performance of the high-frequency driver before continuing, with the power reduced to a level that does not cause the poly switch tointerrupt the signal." the BR's have the poly switch. If the tweeter is cutting out you are using too much power. Get more speakers to get the sound level you want in the rooms you are playing. Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 aaahhh the power of reading. Thank you for the info. I shall cut back on the power until I decide to drop the money on more "suff". Link to comment Share on other sites More sharing options...
Members guitarharv52 Posted June 17, 2007 Members Share Posted June 17, 2007 The BR15 is 250w program (or 125 continuous) according to Musicians Friend.I beleive the 512 is 320 @ 8ohms with all levels at max. Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 yep ... musicians friend is wrong. It is 400/800 according to Yamaha and the little sticker an the back of the cab. Link to comment Share on other sites More sharing options...
Members Al Poulin Posted June 17, 2007 Members Share Posted June 17, 2007 yep ... musicians friend is wrong. It is 400/800 according to Yamaha and the little sticker an the back of the cab. That little sticker SHOULD rather indicate 200 watts RMS and 400 PROGRAM. The peak number is pretty useless and is usually put there by manufacturers to impress people comparing speakers based on how many watts they can handle - not really knowing exactly what kind of watts or how the number was calculated.... Best to apply between RMS and PROGRAM in most cases. Al- Party-Time! DJ Services http://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail/0,,CNTID%25253D27009%252526CTID%25253D229400%252526ATRID%25253D20%252526DETYP%25253DATTRIBUTE,00.html Link to comment Share on other sites More sharing options...
Members swilk Posted June 17, 2007 Author Members Share Posted June 17, 2007 Actually ... after reading more on this subject .... that little sticker SHOULD say: Dont buy me ..... I am treading on the Yamaha name ... I am really not a very good speaker .... You would be wise to spend your money elsewhere ... LOL. No such thing as truth in advertising though. Link to comment Share on other sites More sharing options...
Members Al Poulin Posted June 17, 2007 Members Share Posted June 17, 2007 Actually ... after reading more on this subject .... that little sticker SHOULD say: Dont buy me ..... I am treading on the Yamaha name ... I am really not a very good speaker .... You would be wise to spend your money elsewhere ...LOL. No such thing as truth in advertising though. I have heard the BR12s and 15s and they are not a terrible speaker but it is worth the extra money to get the Club 15s instead. The BRs are less agressive sounding overall which can sometimes be a good thing but for those looking for a Rock 'n' roll (or live sound) speaker that sounds loud and clear in the mid/high frequencies, there are better choices...I found them dull sounding - simply put - last time I compared a total of 8 speaker pairs in my local music store. Al Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 18, 2007 Members Share Posted June 18, 2007 The BR's are an entry level speaker and are fine for small lightweight applications. They are roughly a 200 watt RMS speaker and powering it with between 200-250 watts is probably the best approach. If that's not loud enough you need more speaker AND more amp. The poly-switch is one class of positive coefficient protection devices. Link to comment Share on other sites More sharing options...
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