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From: rdp@teddy.UUCP
Newsgroups: net.audio
Subject: Re: ribbon vs. electro statics
Message-ID: <1069@teddy.UUCP>
Date: Wed, 31-Jul-85 12:55:53 EDT
Article-I.D.: teddy.1069
Posted: Wed Jul 31 12:55:53 1985
Date-Received: Fri, 2-Aug-85 21:29:21 EDT
References: <42400009@hpfclo.UUCP> <351@uwmcsd1.UUCP>
Reply-To: rdp@teddy.UUCP (Richard D. Pierce)
Organization: GenRad, Inc., Concord, Mass.
Lines: 64

In article <351@uwmcsd1.UUCP> shop@uwmcsd1.UUCP (Electronics Shop) writes:
>
>The major difference is that the ribbon is 'just' a tweeter (or mid)
>but a 'static is a full range, although many complain of lack of lower
>bass. A subwoofer helps, but is sometimes too slow, and there might be 
>an audible delay.

AAAARRRRGGGGHHHH!!!!

A subwoofer is "slow" for on reason only, because of it's limited bandwidth!

If you were to take something like an electrostatic, and limit it's upper
cutoff frequency to the same as a subwoofer, it would be just as "slow".
This nonsense about "slow" and "fast" woofers is so silly. The "speed" of
a linear system is a function of it's bandwidth. If something is causing
it to respond to signals slowly, then it's bandwidth will be appropriately
restricted. Period. 

As to the "audible delay", unless it is approaching many hundreds of
milliseconds (given a crossover of less than 200 Hz), there will be
NO audible delay. There might (read WILL) be some phase anomolies, but
nonbody is going to hear a delay.

> Some disadvantages of 'staics are the low impedance,
>sometimes as low as two ohms -- need an arc welder to drive them sometimes.
>Another is the high cost -- my Koss ESP-10 headphones retailed for $350, 
>and Quads can cost up to $2K or more. If you have a limited budget,
>ribbons can be bought to upgrade your existing speakers, or if you
>have bucks and an amp that can power New York City, electrostatics 
>can be the best investment you ever made.
>
>Thomas Krueger

This is simply not so. What is required for driving electrostatics is
an amplifier that can handle highly reactive loads without instability
problems. The only thing you might need high power for is to overcome
an inefficient transducer. This is not a function of impedance. For
example, take a Klipsch horn loudspeaker, which is very efficient. Put
a 2 ohm to 8 ohm matching transformer on the input. You now have a very
efficient, very low impedance loudspeaker. So what?

One of the most pleasing systems I configured was a double pair of Quad
ESL-1's driven by Lux MB3045 tube amplifiers, each running about 5-10
watts class A or about 75 watts class AB. The system played very loudly,
very nicely, not because there was gobs of power (there sure wasn't!),
not because tubes were used, but because the amplifiers were stable with
the load presented. 

This falacy exists, I suspect, because many smaller amplifiers are not
stable into these reactive loads (higher dynamic output impedance maybe?)
On the other hand, higher power amplifiers that people are inclined to
hook these things to are usually more stable, inherently.

Remember that the part of the impedance that constitutes that part that
the amplifiers is actually doing work against, the part of the power that
ends up producing sound, constitutes a very small part of the total
electrical impedance presented by the speaker. (Try going through and
reflecting the radiation impedance back through to the speaker inputs. It
turns out the, except for in the deep bass, the impedance presented by
the loudspeaker would change nearly immeasurably if operated in a vacuum!)

Is there a net.audio.unsubstantiatable_myth news group? :-)

Dick Pierce