Crossovers direct the high frequency sounds to the tweeters and low
frequency sounds to the woofer. They have little low pass and high pass
filters so each speaker only gets the frequencies intended for it.
Jim Altman jaltman@altlaw.com non illegitimus carborundum
http://www.altlaw.com/ 69-TR6#CC28754L W4UCK
-----Original Message-----
From: owner-triumphs@autox.team.net
[mailto:owner-triumphs@autox.team.net]On Behalf Of Larry Hooven
Sent: Friday, January 23, 1998 2:29 AM
To: triumphs@autox.team.net; hobrien@webos1.com
Subject: Re: Spit speakers
isn't that what crossovers are for??
----Original Message Follows----
Date: Thu, 22 Jan 1998 23:41:48 -0600
To: triumphs@autox.team.net
From: hobrien@webos1.com (Will O'Brien)
Subject: Re: Spit speakers
>Will O'Brien wrote:
>>
>> >Joe Curry wrote:
>> >>
>> >> Julian,
>> >> I have two oval 8" dual coaxial speakers mounted on that removable
panel
>> >>behind the
>> >> seats on my '63 Spit. The aftermarket panel is strong enough to
support
>> >>the weight
>> >> of the panels with no noticable effect. The sound is adequate,
>> >>considering that
>> >> the Spit is noisy on its own and the speakers have to compete with
>>the Monza
>> >> Exhaust system. However, It seems to be the only logical space to
>>mount the
>> >> speakers and get proper separation.
>> >>
>> >> If it is a problem with sound bleeding out the back and around the
>> >>edges, you can
>> >> install covers behind the speakers to trap the sound. I would
fabricate
>> >>them out
>> >> of some kind of heavy cardboard and line with foam rubber.
>> >>
>> >> BTW, I don't have the details of your Spit for the International
>> >>Spitfire database
>> >> I am compiling. Please provide the following.
>> >>
>> >> Year
>> >> Model
>> >> Color
>> >> Commission Number
>> >> Owner
>> >> Location (City, County, Country)
>> >>
>> >> Regards,
>> >> Joe Curry
>> >>
>> >> J.Daley wrote:
>> >>
>> >> > I've just got a new radio/cassette for my Spit 1500 and am
trying to
>> >> > optimise the position of the speakers. At the moment I have 2
speakers
>> >> > in the rear panel behind the seats. This is not ideal, as far
as I can
>> >> > see, for at least two reasons
>> >> >
>> >> > 1. The panel is very flimsy.
>> >> > 2. The panel is not well sealed so that sound from the rear of
the
>> >> > speaker can leak round the edges.
>> >> >
>> >> > So from a theoretical point of view this setup should sound
pretty bad,
>> >> > although it may be that if the leaks are small compared to the
volume of
>> >> > the boot (of course the petrol tank is in the way) this problem
is a
>> >> > small one. Has anyone got any practical experience ? Would
reinforcing
>> >> > the panel with some plywood or something make much difference ?
>> >> >
>> >> > I'd also like to put a pair of speakers in the doors, but
looking at
>> >> > it, it looks like there is very little room. Again, has anyone
played
>> >> > around with door speakers ?
>> >> >
>> >> > I'm not looking for the ultimate in high fidelity, just
something that
>> >> > doesn't sound too offensive.
>> >> >
>> >> > Julian.
>> >> >
>> >> > [Third attempt - Does majordomo reject mail if the From: field
doesn't
>> >> > match a subscriber to the list ? I usually send mail from a
different
>> >> > account to the place I read mail, so that may be the problem.]
>> >> >
>>
>>>_________________________________________________________________________
_
>> >>_____
>> >> > Julian Daley, Dept Phonetics, University College
London
>> >> > _______________________________ j.daley@ucl.ac.uk
>> >>_____________________________
>> >>
>> >> --
>> >> "Thanks to the Interstate Highway System, it is now possible
>> >> to travel across the country coast to coast without seeing
>> >> anything." -- Charles Kuralt
>> >
>> >
>> >Depending on the size of the speakers (i.e., around 6 inches in
diameter),
>> >mounting them
>> >on the rear side panels is not really a problem. Those cardboard
pieces
>> >don't have a
>> >lot of strength, but enough for this purpose.
>> >
>> >As for fitting covers to the backs of the speakers, Joe, I believe
this
>> >would only
>> >reduce their effiency. Speaker cones vibrate on two sides -- the
front
>> >and the back.
>> >Enclosing the back is fine, as long as your create a port on the
front
>> >mounting surface
>> >so as to relieve the back pressure -- i.e., "sound" -- coming from
the
>> >backside of the
>> >speaker cone.
>> >
>> >More to the point -- it don't hardly make no damn difference when
you
>> >driving with the
>> >top down, the tailpipe blaring, and the rattles rattlin'.
>> >
>> >--
>> >Martin Secrest
>> >74 Spitty
>> >73 GT6
>> Martin,
>> I hate to burst your bubble. There are actually two kinds of
>> enclosures. One is a sealed enclosure. This type performs better
through
>> the entire range of sound, while a ported or vented enclosure allows
a
>> speaker to perform better in the lower ranges. Did you ever notice
on
>> decent speakers at the store, the three way speakers that have a
tweeter,
>> midrange, and woofer will usually have a port, while the smaller two
way
>> enclosures are usually sealed.(On the decent ones) The two way boxes
have
>> a full range speaker as well as a tweeter to create the sounds in the
>> higher ranges.
>>
>> Will
>>
>> ___________________________________________________________
>> Will O'Brien
>> OS Design & Consulting
>> email: hobrien@webos1.com
>> alt email: will@students.missouri.edu
>> ___________________________________________________________
>
>Aw hell, burst away. Now that you mention it, of course I've seen
>enclosed speakers, but you've left me hanging, Will ... why does
porting
>improve a three-way speaker, but degrade a two-way box of lower
frequency
>capability? Inquiring minds want to .. you know ... know.
>
>--
>secrest
Martin,
When you get into deep bass the speaker has to move back and
forth
very fast or the sound may be distorted. In a sealed enclosure the air
acts as a spring force against the speaker. Therefore it cannot move as
fast. This decrease in speed cn distort hard hitting bass. The
opposite
is also true in the full rage boxes. The hard hitting bass can take
over
the speaker if the it is moving so much that it's momentum causes the
midrage sound to be distorted.
Once again it is a trade off. Seems like it always is eh?
Will
___________________________________________________________
Will O'Brien
OS Design & Consulting
email: hobrien@webos1.com
alt email: will@students.missouri.edu
___________________________________________________________
______________________________________________________
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