[Elecraft] K3 Speaker, Season finale

Wed Apr 24 20:28:08 EDT 2013

I was fortunate to find a used pair of Sounds Sweet speakers for an excellent price at a recent fleamarket.  

I have to say they are well worth the trouble and expense if you can find them.   They are not amplified so there is no interference, and they sound marvelously clear and rich.

-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Brown
Sent: Tuesday, April 23, 2013 10:46 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 Speaker, Season finale

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
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