[Hallicrafters] Now R-42 speaker construction

[jeremy-ca]

This looks like a fair amount of wood to me.
http://www.qsl.net/la5ki/r42.htm

There is another site that I didnt bookmark that stated that the metal box 
surrounded a wooden enclosure. Maybe it was cheapend up over the years.

Carl
KM1H


----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: "Duane Fischer, W8DBF" <dfischer at usol.com>
Cc: "jeremy-ca" <km1h at jeremy.mv.com>; <lrlayton at cox.net>; "Julian Bunn" 
<Julian.Bunn at caltech.edu>; <Hallicrafters at mailman.qth.net>
Sent: Sunday, September 30, 2007 5:24 PM
Subject: Re: [Hallicrafters] Now R-42 speaker construction


> Folks,
>
> I own and use several of these venerable old workhorses.
>
> 1) I have YET to fins ANY wood in their construction!
>
> 2)  The phase concept and ducting for "Bass Reflex" has been known for a 
> LONG time.
>
> Carl - better lining can only improve what it already does.
>
> A wood enclosure "may" even improve it more, but I'll leave that up to 
> those whom want to reinvent the wheel.
>
> Bob N0DGN
>
> Duane Fischer, W8DBF wrote:
>> The Bass Reflex cabinet does not depend on sound absorbing material for 
>> what it does. It uses the aprox. 20% of the sound off the back of the 
>> speaker cone that is wasted, puts it in phase with the sound off the 
>> front of the speaker and in doing so adds an appreciable gain in the low 
>> midrange and bass response.
>>
>> This is accomplished by using a cabinet constructed of a heavy hard wood 
>> that contains a fixed volume of air, said volume partly determined by the 
>> size of the speaker cone, and either a certain diameter circular front 
>> port that puts the cabinet air in phase with the air off the front of the 
>> cone or a tuneable cylendrical tube mounted in the front cabinet port 
>> hole that allows the user to manually tune the interior volume to cause 
>> equal sound phasing. The second method eliminates the need for a cabinet 
>> of a specific size.
>>
>> The purpose of a Bass Reflex cabinet is to utilize the wasted sound off 
>> the back of the cone, not eliminate it by the use of sound absorbing 
>> material. If you do that, then you end up with an infinite baffle 
>> cabinet.
>>
>> Take your pick; infinite baffle, ducted port or folded horn. They all 
>> have advantages and disadvantages. Your need determines which is best for 
>> you.
>>
>> Duane Fischer, W8DBF/WPE8CXO
>>
>