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Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!teddy!rdp
From: rdp@teddy.UUCP
Newsgroups: net.audio
Subject: Re: RAW SPEAKERS
Message-ID: <1099@teddy.UUCP>
Date: Mon, 5-Aug-85 18:00:29 EDT
Article-I.D.: teddy.1099
Posted: Mon Aug  5 18:00:29 1985
Date-Received: Wed, 7-Aug-85 03:57:33 EDT
References: <3177@decwrl.UUCP> <975@teddy.UUCP> <914@druxo.UUCP> <294@ttrdc.UUCP> <1271@hound.UUCP> <578@rtech.UUCP> <228@bocar.UUCP>
Reply-To: rdp@teddy.UUCP (Richard D. Pierce)
Organization: GenRad, Inc., Concord, Mass.
Lines: 35

In article <228@bocar.UUCP> man@bocar.UUCP (M Nevar) writes:
>
>>	This is because most horns, including the Klipschs, are designed to
>>go down to about 40 Hz. or so. However, I have plans for a full 20 Hz. horn
>>that's only 9 feet tall and 16 feet long. Now THAT'S something that will blow
>>your doors off. 
>>-- 
>
>I have just ordered a pair of sub-woofers from a private low-yield speaker
>and electronic manufacturer in New Jersey.  Each is about a 2-foot cube.
>With all the internal baffling and channeling, the speaker (actually a 
>self-made 15-inch woofer) produces an effective horn length of 38 FEET !
>This speaker can be driven to as low as 2 Hz !  This is not a low peak, 
>but has actually driven pink noise at 2 Hz for short periods of time.
>This set-up has forced the maker to re-inforce his listening room.
>
>Mark Nevar

Boy, I hope whoever you ordered them from has a cancellation policy or a
money back policy, because, methinks, you just bought some snake oil.

Why? The cutoff frequency of a horn is dependent upon the size of the mouth
of the horn, and somewhat less upon it's length. Also, the efficiency is
dependent upon the taper characteristics of the horn. It is, I assure you,
impossible to fit a horn capable of doing what is claimed inside a 2 cubic
foot enclosure. Look, for example, a Klipsch's. For abvout a 50 Hz cutoff,
the have an enclosed volume of (I estimate) about 8 cubic feet and, while
they have some severe problems, they really do make it to 50 Hz or so, where
they die like a lead balloon.

The above is a great simplification of course, but there is no way that
the physics will allow the speaker your refering to to do the job that is
claimed for it.

Dick Pierce