On Mon, 14 Apr 2008 18:55:33 -0700, Arny Krueger wrote
(in article <fu11ul0171a@[EMAIL PROTECTED]
>):
> "Sonnova" <sonnova@[EMAIL PROTECTED]
> wrote in message
> news:ftuehs0qqr@[EMAIL PROTECTED]
>
>> I can't give you any recommendations with regard to
>> specific speakers, but I do have a suggestion: Whether
>> you get your current speakers fixed again or buy new ones
>> either put a fuse in-line with the speakers or get a
>> bigger amplifier, or better yet, do both!
>
> The fuse is a good idea. The bigger amp???
>
>> Yes, you heard me right, a BIGGER amplifier. You are
>> likely clipping your Yamaha and clipping amps will fry
>> speakers a lot quicker than will too-much power.
>
> Well, that's a testiable hypothesis, albeit a controversial one.
>
> The down side is that the Yamaha AX-596 is already speced at 100-145
wpc,
> which is actually quite a bit of power.
>
> http://www.yamaha.co.jp/english/product/av/products/hf/ax596.html
>
> The Yamaha AX-596 does have preamp outs and power amp inputs on the back
> panel, normally linked together.
>
> So, a separate power amp can be added without also having to get a new
> preamp.
>
> In order to have appreciably more power, anywhere from 200 (+3 dB) to
400
> (+6 dB) wpc would required. To get twice as loud subjectively without
> clipping, would require 1000 wpc.
>
> There are few consumer power amps with this kind of power for a
reasonable
> price. The pro audio world has some attractive options, but as a rule
they
> have cooling fans which requires that you either risk disabling the fans
or
> put the amps where the fan noise will not disturb your listening.
>
> If you want a lot of clean power for not much money, check out the
Behringer
> EP-2500, which will deliver about 500 wpc into 6 ohms for less than
$400.
> If you clip out this power amp frequently, you will no doubt destroy
your
> speakers. I have a number of friends who have these in very high end
> audiophile systems, and they are very clean and very powerful, despite
the
> low price. To give you an idea of what kind of power these amps can
crank
> out, I've seen them make 12 gauge stranded speaker wires literally
dance to
> the music (writhe and move rhythmically several inches) in the external
> magnetic field of large subwoofers running as 2 ohm loads.
The Behringer amps are all excellent. I'll agree with that.
>
>> As long
>> as the amp isn't clipping, your speakers will tell you in
>> no uncertain terms that you are overdriving them long
>> before any damage occurs (the cones will rattle and the
>> voice coils will bottom-out),
>
> Not necessarily true. A well-designed speaker will be impossible to
bottom
> out. Instead, the magnetic motors for the speakers will run out of force
> before the cone or voice coil hits something solid.
>
> This is especially true of tweeters, because they don't need to stroke
very
> far at all to produce lots of output.
Agreed, but these Cambridge speakers are fairly inexpensive.
>
>> but clipping amps exceed
>> the duty cycles of voice coils and crossover inductors
>> and they get hot with no chance to cool down between
>> waveform peaks (a clipping amp is turned on-HARD for all
>> the time it's clipping essentially dumping lots of
>> current into the speakers non-stop.
>
> This begs the question, which crossover parts can fail, and what happens
> when they fail.
I've seen inductors get so hot that the varnish on the wire burns off
shorting turns. What this will do, at the very least, is to make the
lowpass
not work.
I've seen some speaker crossovers that failed this way in
> the hands of inexperienced DJs, and at frat house and dorm parties. This
is
> a common path to failure of consumer speakers, because consumer speakers
as
> a rule are not intended to be run very loud, very long.
Yep.
>
> It takes a lot of power to fry a crossover coil. Usually, the forms melt
or
> vibration causes enamel to be scraped away and then there may be arcing
and
> burning. I've seen crossover caps with inadequate voltage ratings
explode.
> I've seen power resistors in crossovers that were cracked in half.
Yep.
>
> Overstressed speaker drivers can literally catch on fire, but its more
> likely that the voice coils will slowly cook, the voice coil might buble
and
> hang up on the magnetic pole pieces, and eventually insulation scrapes
off
> and shorts out the voice coil. Or the lead wires fracture, or the
rubbing
> causes an open, and the driver opens up.
True. All of these are known failure modes.
>
>> This is a gross
>> simplification but essentially, when these components get
>> their duty cycles constantly exceeded, they burn-up. A
>> bigger amp will alleviate this problem. I can't imagine a
>> 100 W/channel amplifier damaging any modern, decent
>> speaker.
>
> I've seen it happen, especially to midranges and tweeters. Another
failure
> involves drivers with magnetic damping fluid. The synthetic oil part of
the
> goo gets eva****ated, and its all downhill after that.
>
>> Especially the crossover - unless its clipping and clipping a lot!
>
> The most common source of loudspeaker failure is as you seem to be
> suggesting, simple excessive power causing things to heat up and fry.
Often
> all a more powerful amp accomplishes is to speed the process because it
> takes a lot of power to have an amplifier that sounds significantly
louder
> than 100 wpc.
>
> Looking forward, I see a need for speakers that can handle a lot of
power
> for a long time and keep ticking.
That's ultimately the best solution. Whether its a small amp clipping or a
large one over driving the speakers, the end results can be the same. My
point is that this poster might be listening to music so loudly that the
amp
is in clipping much of the time. More power would allow him to achieve the
same ear-bleeding levels without the clipping - assuming, of course, that
the
speakers are designed to withstand that kind of constant level.
>
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