From: tim@bristolnj.com   
      
   On 4/23/2011 2:54 AM, Fred wrote:   
   > G wrote:   
   >> On Apr 22, 9:50 pm, ddartmedia  wrote:   
   >>> Hi, apologies to anyone annoyed by laypersons' questions here (I got   
   >>> flamed here once before) but I really want to put the question to a   
   >>> community like this; the only alternative I know of is Yahoo Answers   
   >>> (home of "how is babby formed?").   
   >>>   
   >>> I'm wondering if I've blown my speakers. There's no *constant*   
   >>> "bzzzzz" sound with all music I play, but I suspect I hear it very   
   >>> subtly in certain songs (I might be being paranoid), and I'm pretty   
   >>> sure I'm not hearing certain subtleties I once did.   
   >>>   
   >>> Here's the story: my speakers are Infinity Beta 40s, about 3 years   
   >>> old. I don't blast them; never really have. Infinity's "recommended   
   >>> power amplifier range" for them is "10 - 200 watts." My receiver is a   
   >>> 75 watt-per-channel Yamaha RX-497. Until doing it once when the   
   >>> system was turned on, my crawling baby daughter used to really love   
   >>> turning the Yamaha's big, tempting volume knob all the way up. Sure   
   >>> enough, one day I turned on the receiver (which was set to tuner)   
   >>> when the knob was turned all the way up. Of course it started   
   >>> blasting-- for the two seconds or so till I could turn it down.   
   >>>   
   >>> So, considering what my gear is, how likely is it that those few   
   >>> seconds (such an incident may have happened two or three times total)   
   >>> have meaningfully damaged my speakers?   
   >>>   
   >>> Here's a reference to some famous music to try to illustrate: I have   
   >>> the 2009 remasters of the Beatles' mono catalog. In "Taxman," there   
   >>> are those two "beats" (?) that come after lines like "let me tell you   
   >>> how it will be (beat/chord) (beat/chord) / There's one for you 19 for   
   >>> me (beat/chord) (beat/chord)." On those beats, it seems to buzz a   
   >>> bit, even at moderate volume. Is that an indication of speaker   
   >>> damage, or am I just freaking out and forgetting that it always   
   >>> sounded a little distorted there?   
   >>>   
   >>> If this little story is not enough to determine whether my speakers   
   >>> are likely damaged, then what's the best way to determine it?   
   >>>   
   >>> Thanks a lot for any advice as I fret over my very dear speakers.   
   >>>   
   >>> And I'll graciously pass on suggestions about placing my gear out of   
   >>> reach of children (for the kids' sake). After ignoring my instinct to   
   >>> do so, I have now made the responsible adjustments...   
   >>   
   >> I generally listen to them with reduced highs, like in am radio. It's   
   >> easier to hear hf buzz if there is   
   >> Less source highs that cover up the buzz.   
   >>   
   >> Greg   
   >   
   >   
   > Could be a woofer; could be a tweeter.  Could be your paranoia.   
   >   
   > Find a tunable oscillator program on the 'net, hook your computer sound   
   > card up to your stereo if it isn't already, and use the oscillator to run a   
   > slow frequency sweep from 20 or 30 Hz up to 4 or 5 kHz into your   
   > speakers, one at a time.  Turn the level up enough so that if there's a   
   > problem, you will excite it.  But don't get carried away; loud sine waves   
   > can damage tweeters which never see anything like that in real music.   
   >   
   > You will probably excite rattles in your room at low frequencies; do not   
   > confuse those with buzzes / rattles coming from the woofer (or tweeter,   
   > at higher frequencies) under test.   
   >   
   > If you can excite a buzz or rattle in a woofer or tweeter at reasonable   
   > levels this way, that woofer or tweeter is damaged.  If not, not.   
   >   
   > A purist would advise you to replace both woofers or tweeters if you find   
   > one of them damaged.  You sound like a purist, or careful listener, so take   
   > that advice.  Otherwise you'll be noticing subtle differences between your   
   > channels that will slowly drive you crazy and send you to the loony bin.   
   > The new driver will not match up with the 3 year older one, if you're a   
   > careful listener, before you're old and slowly going deaf from the ringing   
   > in your ears.  ;-(   
   >   
   > Fred   
   >   
   >   
   >   
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   >   
   >   
   I would add to that, using the balance control, check one speaker at a   
   time, which will make it easier to figure out where the problem (if any) is.   
      
   Regards,   
   Tim Schwartz   
   Bristol Electronics   
      
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