[Hallicrafters] RE: Why is the R-42 speaker so expensive?

[jeremy-ca]

Reading thru some bass reflex threads on a few audio forums it appears that 
the type and quality of the sound absorber makes a big difference. I think I 
will experiment with some acoustic foam which wasnt even a dream back in 
1945-46 when the R-42 came out.

Carl
KM1H


----- Original Message ----- 
From: <lrlayton at cox.net>
To: "Julian Bunn" <Julian.Bunn at caltech.edu>
Cc: <Hallicrafters at mailman.qth.net>
Sent: Sunday, September 30, 2007 3:03 PM
Subject: Re: [Hallicrafters] RE: Why is the R-42 speaker so expensive?


> Julian,
>
> The R-42 that I have is certainly no open box design, as it is entirely 
> enclosed at the back. The driver is not really that big (8 inches). The 
> metal box and back are lined with very thick felt and the grill at the 
> bottom of the cabinet under the speaker forms a port that is open to the 
> inside of the enclosure.  That would put it in the bass reflex category.
>
> Perhaps you are thinking of the R-46 which is open at the back and has a 
> 10 inch driver. The R-46 cabinet, which is similar in looks from the 
> front, is smaller and lighter than the R-42 and does not have near the 
> amount of bass response.
>
> Les Layton
> Las Vegas, NV
>
> ---- Julian Bunn <Julian.Bunn at caltech.edu> wrote:
>> Yes Bob, you are absolutely correct about speakers in general, but I was
>> not speaking in general, I was talking specifically about the R-42. The 
>> R-42
>> is essentially an open box design.
>>
>> Julian
>>
>> Bob Young wrote:
>> > Cabinet design has a huge impact on the sound of a speaker. A bass
>> > reflex cab is tuned somewhere at or above the resonant frequency of
>> > the driver inside, they are much more efficient and have much better
>> > bass response than an open back cab with the same driver. These cabs
>> > take the back wave of the driver and put it in phase with the front
>> > wave and release it through a port usually below the speaker in front
>> > reinforcing the bass. Open back cabs cancel most of the lower bass
>> > because the back and front waves are out of phase with each other,
>> > ever listen to a driver that is not in a case, no bass at all due to
>> > out of phase cancellation. The only draw back to a bass reflex speaker
>> > is they drop off rapidly below the resonant frequency of the port.
>> > Sealed speakers sound even better as their drop off is much more
>> > gradual, but they are less efficient as they pretty much keep the back
>> > wave right in the cab itself. Many different cab designs. I don't know
>> > if this is anything to do with the price however.
>> >
>> > Bob
>> > KB1OKL
>> >
>> > Message: 4
>> > Date: Sat, 29 Sep 2007 18:42:17 -0700
>> > From: Julian Bunn <Julian.Bunn at caltech.edu>
>> > Subject: Re: [Hallicrafters] Why is the R-42 speaker so expensive?
>> > To: jeremy-ca <km1h at jeremy.mv.com>
>> > Cc: hallicrafters at mailman.qth.net
>> > Message-ID: <46FEFEF9.4020302 at caltech.edu>
>> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>> >
>> > I think the sound is good simply by virtue of the size of the driver.
>> > The cabinet probably has
>> > minimal or no effect on the acoustics, IMHO.
>> >
>> > No idea why they are so expensive ... I picked mine up very reasonably
>> > from a chap who
>> > was selling an SX71 and it came with it.
>> >
>> > Julian
>> >
>> >
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