Re: Why not closed loop speaker amplification?

Ross Herbert wrote:
> On Tue, 07 Jun 2005 12:58:41 -0400, Kalman Rubinson <kr4@xxxxxxx>
> wrote:
>
>> On 7 Jun 2005 09:45:24 -0700, bill.sloman@xxxxxxxx wrote:
>>
>>> It has been done - some years ago Philips used to sell loudspeakers
>>> that worked on this principle. They weren't all that good, probably
>>> because the position of the diaphragm is measured at one point, and
>>> the diaphragm, not being infinitely rigid, distorts under load.
>>>
>>> IIRR Philips used an accelerometer mounted on the drive coil as
>>> their "position" sensor.
>>
>> And it is currently being done on many 'servo' subwoofers.
>>
>> Kal
>
> Audio Express 9/04 described a 12" Dual Voice Coil Subwoofer system
> designed by Daniel L. Ferguson. The second voice coil is used as the
> feedback transducer.

That has been tried a lot, but the mutual coupling between the coils make
this approach pretty much useless.
--
ciao Ban
Bordighera, Italy


.

Relevant Pages

  • Re: Dynamic range of a Behringer ECM8000
    ... Part of what happens to the SM-57 at high levels is that the diaphragm ... COUPLING from the speaker voice coil or the output transformer to the ... mic voice coil or mic matching transformer. ...
    (rec.audio.pro)
  • Re: Looking for a good tom and floor tom mic??
    ... that holds it to the diaphragm goes bad, and the voice coil gets stuck ... Suddenly the diaphragm is very damped at low ... It's really a great mike. ... C'est suisse, et tres, tres precis." ...
    (rec.audio.pro)
  • Re: Best Speaker(s) for Cleans (MusicMan HD130 Reverb)
    ... adam79 wrote: ... the voice coil is what I thought the cone was.. ... Replace voice coil with diaphragm! ...
    (alt.guitar.amps)