Can an EQ damage speakers?
michael santos
some info if at all possible.
I remember hearing or reading somewhere that one should be careful with an
equalizer. Apparently, the infrasonic (subsonic?) frequencies can damage
speaker drivers if the low bass and high treble frequencies are boosted
too much.
I have a five year old ADC Sound Shaper SS-100SL equalizer. It allows a
-/+15 dB cut/boost at the following frequencies: 31.5Hz, 63, 125, 250, 500,
1k, 2k, 4k, 8k, and 16k. My speakers are a new pair of B&W600i (small
bookshelves with a 6.5"woofer and 1"dome tweeter). They are terrific
little speakers whose sound does not suggest their small size. Of course,
no matter how good the sound, the laws of physics does not allow certain
amount of bass to be had from a small enclosure. To compensate somewhat,
I employ my EQ to boost the lower freq's (esp. @ 31.5 and 63 Hz).
The EQ's manual claims: "A precision 18 cB/octave infrasonic filter below
20Hz, active at all times, means cleaner bass response - for example, no
dangerous rumble - even during potent low-frequency boosts".
Can I trust the EQ's manual on this? Am I endangering my speakers with
too much boost. So far, I have not noticed any audible distortion, but I
have yet to really push the B&W's in terms of volume. When I do, I defeat
the EQ beforehand just to be sure.
What do you make of all this?
TIA :-)
PS, I hope this doesn't start another heated discussion the way my
original post on bi-wiring did a month ago ;-)
--
ciao,
Michael Santos
Carleton University
"Get your head out of the mud baby..."
-u2
Eric Thomas
In a previous article, msa...@superior.carleton.ca (michael santos) says:
>Hello. I would appreciate some of you knowledgeable fellows providing
>some info if at all possible.
>
>I remember hearing or reading somewhere that one should be careful with an
>equalizer. Apparently, the infrasonic (subsonic?) frequencies can damage
>speaker drivers if the low bass and high treble frequencies are boosted
>too much.
There are a couple of things to take into consideration when using an
equalizer. For instance, when you boost low frequencies (say with the 30Hz
and 60 Hz sliders for example) your speakers' woofers will typically
(depending on the musical content) move back and forth at a greater
distance ... known as speaker excursion.
As long as the volume level of your amplifier is not set so high that the
woofer looks like it's going to pop out of it's basket, or has
distortion/popping sounds, you are probably not going to run into any
difficulties. However, take into consideration the dynamic range
potential of the musical source. For example if you crank up your volume
because you are listening to a soft passage in a song/melody, be aware
that the recording levels may all of a sudden jump up (this is when you
woofer may become a pop tart).
As for high treble frequency equalization boosts, you may want to make
sure that your amplifier does not clip or distort when played at higher power
levels.
Tweeters may often burn out when the amplifier starts to get overloaded,
causing an imperfect sine wave. Consequently, a distorted signal may burn
out the tweeter's coil (that is if it is dynamic and not a piezo tweeter).
Also, you may want to take into consideration the speaker power ratings in
relation to what your amplifier specifications are.
>The EQ's manual claims: "A precision 18 cB/octave infrasonic filter below
>20Hz, active at all times, means cleaner bass response - for example, no
>dangerous rumble - even during potent low-frequency boosts".
Subsonic filters were especially useful back in the days of records when a
warped LP could cause low frequency rumble. This could damage speakers if
the power levels were set high enough (woofer excursion problems). With
CD's you usually don't run into this problem, unless you are listening to,
for example, a soundtrack of a movie with sound effects etc. that are very
low frequency in nature.
>Can I trust the EQ's manual on this? Am I endangering my speakers with
>too much boost. So far, I have not noticed any audible distortion, but I
>have yet to really push the B&W's in terms of volume. When I do, I defeat
>the EQ beforehand just to be sure.
How much boost are we talking about (db)? Is your amplifier or receiver's
tone controls cranked up too? Is your amp's loudness button on, or
continually variable loudness control cranked up (or down)? These
settings are also important to consider in an effort to answer your
question.
>What do you make of all this?
Why don't you ditch the equalizer (at least as an experiement), and just
use your amplifier's tone controls to fiddle around with the high and low
end frequency boosts? If the tone controls do the job, then I'd forget about
using the equalizer. It just adds distortion to the signal anyway. I
always found that equalizers were very difficult to properly set.
However, very small boosts (up/down 3db) may still be necessary for
certain frequencies if all else fails.
Have you considered moving your speakers around your listening room in an
attempt to see if the sound improves? If you put your speakers in your
room's corners, bass will be louder etc... Are your speakers on stands?
What kind of music do you like listening to? Most rock and roll music
does not go down much below 60Hz -- except for some synth stuff etc... If
you like listening do contra bass or pipe organ music, consider getting a
subwoofer. A cheaper alternative may be headphones :-)
>PS, I hope this doesn't start another heated discussion the way my
>original post on bi-wiring did a month ago ;-)
No doubt. I'm wearing my asbestos suit.
--
+_________________________________________________________________+
| Eric Thomas, Ottawa, Ont. Canada. ae...@freenet.carleton.ca |
+-----------------------------------------------------------------+
Lon Stowell
>equalizer. Apparently, the infrasonic (subsonic?) frequencies can damage
>speaker drivers if the low bass and high treble frequencies are boosted
>too much.
If you overboost the bass, first it will sound like a cheap
boom-boom box. MOST speakers produce audible warnings long
before you can damage the BASS drivers with over-boost in the bass.
>1k, 2k, 4k, 8k, and 16k. My speakers are a new pair of B&W600i (small
>bookshelves with a 6.5"woofer and 1"dome tweeter). They are terrific
>little speakers whose sound does not suggest their small size. Of course,
>no matter how good the sound, the laws of physics does not allow certain
>amount of bass to be had from a small enclosure. To compensate somewhat,
>I employ my EQ to boost the lower freq's (esp. @ 31.5 and 63 Hz).
No big deal. You should hear nasty clacking, whacking noises before
you really hurt the drivers.
The danger of too much bass boost with modest amplifiers is that you
may cause the amp to clip...which can destroy your tweeters long
before you'll notice much problem with the bass.....but again if you
listen carefully you can usually hear the warning signs of clipping.
The sound will begin to assume a somewhat "harsher" or more metallic
sound...usually.
The cure of course, is to turn the gain knob a bit below "eleven".
The B&W's are reasonably robust speakers, you might be surprised at
how much abuse they will absorb before damage ensues....