I use a CLRSpeach DSP speaker. It helps a lot. However, I am curious about your noise. With everything turned off, how many signal bars are shown on the M802 display?
One common
installation error is connecting the M802 to the breaker panel instead of the
battery directly. The
battery is a giant filter as it likes DC and squashes noise signals.
Do you have a long run to the battery or are you using the supplied cable from Icom. If so, twisting the cable will help eliminate noise coming in through the
power supply. I also recommend a mix 31 ferrite
core at the back of the transceiver on the
power supply line. If you use one built for RG8, you should be able to loop the DC wire at least 2 times through the snap on
core. Make your loops equal and tight will result in the effect of having 4
single cores on the line.
If your noise is coming in through the
antenna and everything is off, it is what it is. I would check for something that may be on all the time or possibly a ground loop. Your 12VDC should come to the
radio. The ground on the control cable should be attached to the ground lug on the transceiver. The ground wire on the tuner end should be cut off and not connected. The only thing coming off the tuner lug should be your RF ground. The RF ground should not be connected to anything that is also connected to the -12V side of the battery e.g.
engine, bonding etc.
Here is a link to a document I put together to help cruisers make sure they have a good
installation:
http://www.made-simplefor-cruisers.c...e%20M802-1.pdf
I hope that helps.