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Old November 14th 05, 02:52 PM
craig
 
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Default ABOUT - External Speakers for the Icom IC-R75 Receiver

Ryan ...

You have several good options, many of which have been mentioned above.
The biggest factor to consider when sorting through them all is the
type of content you like to listen to.

If you primarily are interested in extended listening to strong
broadcast and SW stations, you would want to have reasonable fidelity,
high audio bandwidth and possibly high volume available to you. For
this you would want to use computer speakers or equavilent or the
Sounds Sweet approach. With my R75, I have the line out signal
(labeled REC) connected to the line in of a Tivoli Audio Model One mono
receiver. This small radio gives excellent audio when listening to
broadcasts with high signal strengths and low background noise.

For more difficult listening situations, such as ham radio, utility
stations, DXing, etc., the above approach is worse than the internal
R75 speaker due to the exessive audio bandwidth. For these types of
applications, you want to limit the bandwidth to exclude as much
extraneous noise as possible, and accept some loss of fidelity. At low
audio levels, I would rate the internal R75 speaker as approaching
adequate in this regard. But as you have found, it does have some
distortion and a very limited dynamic range. One good improvement
should be the ICOM SP-23 external speaker. This unit provides higher
sound levels and has selectable audio filters so that the lowpass and
highpass response can be tailored to the content you are listining to.
- i.e., high bandwidth for AM, medium for SSB and narrow for CW. It
is complety passive and is driven by the 8 ohm external speaker line
from the R75. Looks like a very flexible device. The downside is that
it is fairly pricey - about $170. I will be getting one next month and
am looking forward to evaluating it as I do a lot of CW on the ham
bands. Will post my evaluation here in a month or so.

A third alternative, if you don't mind being tied to a computer, would
be to tie the R75 line out to a computer sound card and use a DSP audio
filter program on the computer to drive the computer speakers. This
would give you the ultimate in customization of the audio response to
various listening situations.

... Craig