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ODD HARMONICS
Loudspeakers can introduce distortion with harmonic resonance, which
can sometimes be greater than the fundamental. Odd harmonics seem
to be musically worse than even harmonics. And neither is obviously
best.
Another common occurrence is ringing, which is basically the cone
or diaphragm that carries on bouncing around long after the original
signal has ceased. The cure for this is more dampening. However,
the most frequent source of distortion is over-driving the loudspeakers.
I’m not talking about giving them more watts than their voice
coils are able to handle temperature-wise, but the sheer inability
of most loudspeakers to deliver clean sound at just 50% of their
rated power, bearing in mind how large the harmonic distortion numbers
are at the AES standard of 10% of rated power.
And whilst I am on this subject, I really must take extreme exception
to probably the most ridiculous measurement parameter that has been
introduced in the last 20 years, namely the terminal SPL figure.
This is a function of power rating, sensitivity and power compression.
Taking into account the above points, 100% power input into a loudspeaker
is going to result in the most dreadful audio and therefore is completely
irrelevant.
In contrast, I cannot help but notice a dearth of published distortion
figures for most speaker systems now on the market. This wasn’t
the case in the past, so I am concluding that in fact the business
has in some respects gone backward, and there’s a general
tacit agreement not to publish these embarrassing specifications
anymore.
TORRENT OF NOISE
The difference between clean, well-defined sound and the all-too-frequent
torrent of white noise cannot be over emphasized. Firstly, working
in the usual stereo mode, the producer will have the instruments
mapped out on the sound stage. In the multidimensional internal
listening space, the separation and placement of these instruments
will be apparent and easy to find. Distortion prevents this subtle,
mental reconstruction process by changing the audio information.
While this is bad enough on its own, what’s even more important
is the fact that the ugly sound literally drives you away, much
like your desire to leave the company of an aggressive and vexatious
person. There is no way under these conditions that you are going
to open your mind to the possibilities of a multi-dimensional sound
stage inside your head.
But I am beginning to realize that there are many so-called audio
engineers who have lived with awful sound systems for so long that
they have no idea what I am talking about. You know the kind of
people I mean the ones who say, “Make their ears bleed.”
Crushing level is absolutely NOT what the audio experience is about.
It IS about internal space. Anyone who really knows will understand
that a righteous audio experience is akin to meditation.
A yet further aspect of this is the complete abuse of fee-paying
audiences with horrendous sound. Let’s remember that being
able to enjoy music, nay sound, is one of our freedoms, and it breaks
my heart to see it so consistently abused and misapplied.
From his early steps with his live sound rental company to his
current involvement in the evolution of loudspeaker engineering,
Tony Andrews has a maintained a consistent focus on maximizing efficiency
and optimizing the conversion of amplifier energy into acoustic
energy. He also digs windsurfing.
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