Re: [Phys-L] Suggestions for audio speakers

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2013, Mar 15, , at 13:40, "John Clement" <clement@hal-pc.org> wrote:

> Nobody seems to have addressed what you are asking for, so here is an
> attempt to do this.
> 1.  It is impossible to have speakers that have flat response down to 20Hz
> that are also portable.  Basically you need large woofers to reproduce low
> frequency sounds.  Below the resonance frequency of the cabinet/woofer
> system the sound cuts off sharply.  Ported speakers extend the low
> frequency, but then the cut off is even sharper. 


The engineer I previously mentioned designed semi-portable systems w/ great value for the money.  A typical one consisted of six oval (5 X 7") speakers (wired series parallel) mounted on a baffle board and sides v. ~ a foot (open back).  One placed it for "optimum sound".  A novel innovation was to short the "nodes", so that one speaker's resonance would be damped by its "brother".  If expensive speakers were used, this wouldn't work!   He would demo A-B with much more expensive ones -- Many would conclude not worth the extra money. 

Two advantages:  Good bass response from the large area, and good mid range from the low mass --

Another innovation was to rigidize the cone w/ a low density building material whose composition a secret  I never learned.  It looked like the white spray on sound absorber.  This, I suppose, improved the higher frequency response.  He also experimented lowering woofer speaker resonance by using glued on wire solder.  He also made3 acoustic suspension speakers.  [ca 1956]


bc former subscriber to speaker builder magazine.

p.s.  All I saved from the Audio Amateur mag. was the drop out detector article for my Sony PCM-F1.