bill@dual.UUCP (Bill Kanawyer) (03/18/84)
< Food of the gods >
Sometimes when one has all of the background information in ones head
one thinks that everyone else has too.
I made two statements in an earler article (reference 352@dual.UUCP)
without giving enough information to allow proper understanding on the
readers part. My statements in short were:
1) I thought that AR-11 tweeters were under rated on power handling.
2) I did not like their (the tweeters) sound.
The person who's login is rdc@opus.UUCP pointed out to me (and everyone
else, reference 240@opus.UUCP) that the effect noted in the two statements
could be caused by over driving the speakers.
THIS IS QUITE TRUE
However, please allow me to add a couple of things that will help you
to better understanding my experences with AR-11s.
As said, I was using a large number of AR-11 in the theater that I was
running shows in. The speakers WERE wired to a large (1000 watts) amp. In
order to maintain proper loading for the amp they were wired in a serial -
parallel circuit (8 ohms looking into the array) and were properly fused.
For my own interest a pair were taken home and played on a 30W amp
at low to moderate levels (<80 - 85 db).
In addition I have known 3 different people who have owned AR-11 and
all three have blown drivers. Not madmen who like to "crank it way up"
but just regular guys... like you and me.
So, now that you know all of this I will state my opinions again.
(1) I did not care for the sound of the AR-11 tweeters. They tended
to be harsher then I care for... but then I am sensative to high freqs.
I also do not like most horn and pizo tweeters.
(2) My experence is that the mid-range drivers and tweeters can be
too easly blown by transients for which fusing is no protection. They
will blow at the drop of a hat (or needle). The most common cause of
failure (in my experence) is that the voice coil opens up.
I should say that over all the sound of the AR-11 seems good. People
who like AR products should be happy with the sound. (My own feeling is
the AR-3a is a better product) Just remember when buying these to use
them with a amp of modest power. 30 watts per is more then enough to use.
Also remember to turn your gain down before changing records.
I am sorry that this turned out to be so long. I had hoped to be able
to make my statement in just a few words. If I have still failed to make
my self clear... please feel free to write me.
Bill Kanawyer
{ucbvax,amd70,ihnp4,cbosgd,decwrl,fortune,zehntel}!dual!billpeters@cubsvax.UUCP (03/21/84)
You tell people to take the precaution of operating low-power-rated
tweeters with amps of modest power. NOTHING COULD BE WORSE!... especially
if the efficiency of the driver is low.
What happens is that the amp goes into clipping at any attempt to achieve
moderately loud sounds. This generates high harmonics (since a clipped
sine wave is like a square wave), overloads the high end, and blows the
tweeters.
Paradoxically, low-power-rated tweeters should always be operated with
relatively high-powered amps. If this is done, higher volumes can be
safely achieved than with an amp whose output is comparable to the
rating of the driver.
{philabs,cmcl2!rocky2}!cubsvax!peters Peter S. Shenkin
Dept of Biol. Sci.; Columbia Univ.; New York, N. Y. 10027; 212-280-5517dmmartindale@watcgl.UUCP (Dave Martindale) (03/22/84)
To put this another way, if you feed MUSIC to a high-power amplifier, then it will either drive the speakers cleanly or, if the signal level gets too high, blow the speaker fuse. It won't fry the tweeter unless there is a very high level of high-frequency energy in the music, which there almost never is. The argument about using a lower-powered amplifier to protect your tweeter applies only if you have a separate amplifier for the tweeter which is fed only high-frequency signals. There, there is no danger of clipping of high-amplitude low-frequency signals (which aren't supposed to be reaching the tweeter at all) generating harmonics. Note that tweeters are likely to be rated for 5 or 10 watts power input, so protecting them by using a power amplifier which is completely incapable of damaging them means having an amplifier which can't reasonably drive the woofer at all.