Home Elecraft K4D Noise Reduction compared to BHI NR module

[Moleculo]

I've owned the Elecraft K4D for a while now. It's a wonderful rig. However, I am deeply disappointed in the NR capabilities on SSB and several have brought this up on the various Elecraft forums. Wayne N6KR, one of the Principals of Elecraft has commented that they intend to improve it by adding spectral subtraction algorithms, but for now it's basically a copy/paste of the code from the older K3 rig. I got tired of waiting around and decided to improve the situation by trying out the BHI Dual In-Line Noise Eliminating Module.

Because the Elecraft K4D has stereo speaker / headphone output (which is used in a variety of ways), it was important to me to buy this specific BHI box, which supports both external stereo speakers and stereo headphones. They can be used independently or together and even have separate volume controls. I shot a brief video doing a quick demonstration of both unit's NR capabilities, as well as using them both together. Note that I could have made additional adjustments on the BHI module, but I felt the demonstration was good enough as is. To keep the comparison on a level playing field, I made no additional adjustments on the K4 other than adjusting the volume as needed.

What do you think?

 

[W4KVW]

I use the BHI & ClearSpeech DSP modules or DSP Speakers with every radio I own that does SSB or AM & that includes my ICOM 7610,ICOM 9100,ICOM 7000,& ICOM 703+. I HATE noise so I do what I can to remove any & all of it that I possibly can. I have never heard ANY radio that can compare to the external DSP units. I understand that they are two different types of DSP but the radio manufactures should take notes & add both types to their radios. NOISE SUCKS & it makes Listening stressful on your ears. You can't work what you can't hear.

 

[Divyardah]

I found the built-in NR worked better on speech but didn’t clean up steady background noise as well. Playing with the settings helped some, especially adjusting the threshold and level.

 

[W4KVW]

I use the BHI & ClearSpeech DSP modules or DSP Speakers with every radio I own that does SSB or AM & that includes my ICOM 7610,ICOM 9100,ICOM 7000,& ICOM 703+. I HATE noise so I do what I can to remove any & all of it that I possibly can. I have never heard ANY radio that can compare to the external DSP units. I understand that they are two different types of DSP but the radio manufactures should take notes & add both types to their radios. NOISE SUCKS & it makes Listening stressful on your ears. You can't work what you can't hear.

I am now using the ClearSpeech DSP module with my YAESU FT-920 as a backup radio & it really helps it. I don't believe the AF DSP in the 920 is up to what the IF DSP is in the ICOM radios, so the external DSP makes a bigger difference on the received signals. I own the same Dual Inline unit pictured as well. It's great for the ICOM 7610 or the ICOM 9100 that have Dual Receivers, so I only need one DSP unit for the radio.

 

[Divyardah]

I found the built-in NR worked better on speech but didn’t clean up steady background noise as well. Playing with the settings helped some, especially adjusting the threshold and level.

I had decent results tackling background shack noise by lining parts of my operating desk and radio shelf with auto sound deadening mat. It didn’t help with RF or digital hash, but it really cut down on fan noise and rattles, which made a difference when listening at low volumes. Pairing that with DSP onboard makes long sessions less fatiguing for sure.

 

[W4KVW]

I had decent results tackling background shack noise by lining parts of my operating desk and radio shelf with auto sound deadening mat. It didn’t help with RF or digital hash, but it really cut down on fan noise and rattles, which made a difference when listening at low volumes. Pairing that with DSP onboard makes long sessions less fatiguing for sure.

I use a Quality Studio Microphone that does not pick up most background noises. The HEIL FIN with my ICOM 7610, Electro Voice RE 320 with my ICOM 9100, HEIL PR20 on many radios, & HEIL iCM on my older ICOM radios are very very good at cancelling the background noises.