[Elecraft] K3 Speaker, Season finale

[Jim Brown]

On 4/23/2013 8:44 AM, Ramon Tristani wrote:
> And last but not least, what is the science of designing a transceiver with so many advanced features if the output product, the sound coming out of the speaker, is mediocre at best?

As a retired audio professional (Fellow of the Audio Engineering 
Society), ham for 55 years, and contester since 1957, I have several 
thoughts on this question.

1) The science of loudspeaker design, while well understood, is so far 
removed from the science of building high quality radio transceivers 
that it makes no sense for a small company like Elecraft to devote their 
limited engineering resources to designing and building one.

2) For any serious operating, I've always used headphones.  I use a 
loudspeaker only for casual operation, and for monitoring while I'm in 
the shack doing somethings else.

3) The "ideal" loudspeaker for ham radio is nothing more or less than 
one that has very smooth, uniform ("flat) frequency response in the 
range of 200 - 4,000 Hz, maintains that uniformity over a wide range of 
angles where the listener is likely to have his/her ears. It should 
either be sufficiently efficient that it can be made loud enough by the 
relatively small speaker amplifiers in the K3, or it should have its own 
internal power amplifier.

The problem with loudspeakers having internal power amplifiers is that 
nearly all I have seen, including some rather expensive pro models, have 
serious RFI problems.

Loudspeakers that are relatively small tend to have smooth response over 
wider angles, but they also tend to be less efficient (that is, they 
take a bit more power to drive).

Bottom line -- Elecraft made exactly the right decision to stay out of 
the loudspeaker business. If you want an outboard loudspeaker for ANY 
ham rig, simply look in the pro audio world for one that has flat 
response, sensitivity of at least 80 dBSPL for 1 watt at 1 meter, and 
fits on your operating desk.  Look for audio products, not radio 
products. The best I know of is the RCF MR55, which is made in Italy and 
distributed worldwide. I've used them in some very high quality 
professional installations.

http://www.rcf.it/products/installed-sound-systems/monitor-series/mr-55

Exception -- for many years, Motorola has marketed some small 
loudspeakers designed for use with their commercial VHF/UHF transceivers 
that works well for ham radio.

73, Jim k9YC