[AMRadio] Hallicrafters R-12 speaker

[Bob Peters]

That makes it just about right   Our 10 oz are
rated at 40 watts...We use them in a 70V config
with a max of 15 watts...With a good can they
sound great...Speakers with no backing are CRAP...
That is why enclosure is so important...My Shack
speaker is an original 15 inch Jensen with a 20 lb
magnet. It was the first coax speaker Jensen
made... It is in a blonde Jensen box that has 2
inches of sound deadning material and is bass
ported in the rear. This make SW BROADCAST sound
like a dream...

Bob W1PE

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf
Of rbethman
Sent: Friday, September 04, 2009 8:27 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Hallicrafters R-12 speaker

The Jensen P12R uses a 7 oz. alnico.  It is rated
at 25 Watts.  
Certainly more than the radio will do by itself.

My experience is that alnico magnets are more
powerful per ounce than 
old-fashioned ones.

That is why they use alnico and sometimes
"rare-earth" materials in the 
head assembly of computer hard drives.

It is one of the reasons for the reduction in size
of drives.

Bob - N0DGN

Bob Peters wrote:
> You are correct... They used Jensen and Quam but
> only used 10 oz magnets...The magnet size is
what
> determines sound quality on a speaker... My
> company manufactures both 5 and 10 oz but only
up
> to 8 "...Now you make that speaker a coaxial and
> it will improve the quality by 50% or
> more...Speakers are just like radio's... The
> better the enclosure the better the speaker like
a
> transmitter and an antenna...
>
> More later on enclosure design///
>
> Bob W1PE
>
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net] On
Behalf
> Of rbethman
> Sent: Friday, September 04, 2009 6:21 PM
> To: Discussion of AM Radio in the Amateur
Service
> Subject: Re: [AMRadio] Hallicrafters R-12
speaker
>
> Well, a Jensen P12R isn't "much" different in
> price.
>
> The originals I do believe were made by Jensen.
>
> Bob - N0DGN
>   

-- 
+-------------------------------------------------
-----------------+
|             AM Amateur Radio Operator    NØDGN
|   
+-------------------------------------------------
-----------------+
| Bob Bethman                \\\|///     " The
absence of a danger |
|                           \\ ~ ~ //      signal
does *NOT* mean  |
| rbethman at comcast.net      (/ @ @ /)      that
everything is OK " |
+----------------------o00o---°(_)°---o00o--------
-----------------+

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