inverse response speaker flattening

[Harry Bissell]

Hi Martin (et al)

Switching Amps (Class D and above) are actually COMMON today
(well maybe I stretch the truth... common for laptop computer audio
systems). They allow very high efficiency, so they save battery power
especially at lower levels where bias current would hurt. High efficiency
also means very small footprint...

Check out Texas Instruments website for chips, appnotes, evaluation
boards and some papers they wrote recently, especially the one
regarding the choise of output filter vs distortion. Not what you (I?)
expect...  Power is in the 20W class.

OTOH I will not be using this design soon. Analog RULES

BTW:  My little Stewart "switching power supply" amp does not
hold a candle to my (linear) JBL. The band CAN tell the difference.
OTOH: If I had to choose one to go swimming with....

H^) harry

Martin Czech wrote:

> There is one thing I wonder about:
>
> You have music from digital sources all the way, till power amplifier. It
> would be no problem to ship a little digital in/out box with a measuring
> microphone, so that anyone can measure the frequency response of his room
> and his speakers, the box takes the inverse to filter the CD data. That
> should give an almost ideal response for that single measuring point in
> space and hopefully around it.
>
> Of course, once the speakers are flattened, any personal taste could be
> applied as well (bath tub).
>
> One problem could be that shitty bass chassis could not take the needed
> power...
>
> I have never seen any advertisement for such an apparatus, it seems that
> something like that simply does not exist.
>
> Another question:
>
> In the 70ties people thought about switching amplifiers.
> I.e. DAC amplifiers. The audio chain would be digital up to
> the speakers. Are there any reasonable advances/designs
> today?
>
> m.c.