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Path: utzoo!watmath!clyde!bonnie!saf
From: saf@bonnie.UUCP (Steve Falco)
Newsgroups: net.audio
Subject: Re: Speaker Sensitivity
Message-ID: <601@bonnie.UUCP>
Date: Tue, 29-Oct-85 08:58:53 EST
Article-I.D.: bonnie.601
Posted: Tue Oct 29 08:58:53 1985
Date-Received: Wed, 30-Oct-85 05:40:27 EST
References: <480@uvaee.UUCP>
Organization: AT&T Bell Laboratories, Whippany NJ
Lines: 26

> Does anyone know how the speaker configuration (vented, sealed, etc.)
> affects a woofers sensitivity?  Acoustic suspension speakers are known
> for being less efficient than bass reflex speakers :-)
> Is this because IT IS an acoustic suspension speaker, or is it because
> the drivers used are less efficient than drivers used in vented speakers?
> 
> Does anyone know how to decide if a driver will work in a TL or horn?

Acoustic suspension is less efficient than bass reflex for a couple of
reasons.  First, in bass reflex, the sound from the port adds to the
volume while in acoustic suspension, that sound never leaves the box.
Second, acousic suspension is very springy because the air is trapped.
Consequently, it retards cone motion.

For horns, you want a driver with a stiff suspension.  Not rolled
polyfoam!  Klipsch uses an old style cloth accordion pleat which is
quite stiff (made by Eminence (sp?)).

Now here's my question:  If you seal the box for acoustic suspension,
how do you handle changing barometric pressure - it tends to displace
the cone from center...  Maybe there should be a valve on the side of
the box to allow mountain dwellers to bleed off some of that extra air
the factory put in the box.  (Guess I'd better put a :-) in to avoid the
flamers...)

	Steve Falco