[Icom] Icom 756 Pro II Speaker Options

[George, W5YR]

My experience is that nothing short of a large speaker cabinet with large
speakers and quite a few watts pushing them will display fully the audio
quality that the PRO and PRO II are capable of delivering.

When I got my PRO I immediately connected it to the SP-20 that I used for
about 10 years with my IC-765. Compared to the 765 - which has to have the
worst audio ever placed before a radio operator from a quality radio - the
PRO sounded heavenly. But "thin . . ."

So, after Bob Heil talked me into getting a Behringer MX602A Mixer/EQ, I
hooked the PRO rear-connector receive audio into the 602 and then used its
line output to drive an old 100 w/channel stereo receiver with a busted
tuner. I had an old 60's vintage large Zenith stereo system with defunct
electronics but excellent lage woofers and horn midrange and tweeters.

With all that, the PRO sound really came alive. The system is capable of
shaking the shack walls at 40 Hz and the PRO will deliver audio very nearly
down to zero Hz, based upon actual scope measurements. It was with this
setup that I was able to confirm the infamous PRO Rumble Effect and make
.wav recordings of it for Jim and Tony to use in tracking down the cause.

Now, I will be the first to agree that this is overkill for a
communications receiver, but the invested cost in my case was nearly zero
and the results are superb. For the first time I was able to hear at least
some of what the 14178 gang were doing and to appreciate their usually
clean though wide-range audio. If you have wondered why all the fuss about
hi-fi SSB, listen on a wide-range audio system and you will find out.

If your circumstances are such that you must use a small speaker, the SP-20
is more than adequate and the small Radio Shack units are very good as
well. But, for the whole picture, you need a fairly large speaker with some
watts behind it.

I also have found that wide-range headphones are equally pleasant and
effective to use, even on CW. I use the Heil ProSet and despite its very
wide frequency range, the PRO and the (now) 802A mixer EQ control the
frequency range that I actually hear. I still have the old surplus WW2 Air
Corps headset with the big padded leather ear-muffs which I used for many
years (starting in 1946!) working CW. They work well with the PRO, despite
the high-Z, but the peaked response grows tiring in a hurry.

Each to his own, but I have really enjoyed being able to hear the
wide-frequency-range super clean audio that the PRO is capable of
delivering from its rear-panel connector. For the record, all the spectra
that I have taken and other tests confirm that the  analog audio output
circuitry in the PRO is a disgrace to the remainder of the radio.

73/72/oo, George W5YR - the Yellow Rose of Texas         
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437


Jim Gerke wrote:
> 
> Jim,
> 
> I highly recommend the Yaesu SP-8. It's their equivalent to Icom's SP-20
> but, IMHO, is much better. It has the most flexible audio tailoring I've
> ever seen in an accessory speaker and it costs a lost less than the
> SP-20. Unlike the SP-20, the SP-8 is really black in color and matches
> the newer Icoms much more nicely.
> 
> I bought my SP-8 about 5 or 6 years ago to match an FT-920 that I
> purchased at the same time. I disposed of the 920 long ago but have hung
> on to the speaker and used it with a TS-850, IC-775DSP, and IC-756Pro.
> It's the best speaker with audio filtering I've ever had.