IMPRES XP RSM waterfall noise on XPR-7550e

[KC1LKO]

Hello group.

I have a 7550e which I have been using for some time with a PMMN4025 - IMPRES™ Remote Speaker Microphone - Motorola Solutions - EMEA with no issues.

Just bought a used backup 7550e along with a nicer handheld Mic - IMPRESS XP RSM https://shop.motorolasolutions.com/...ppression-rugged-submersible/product/NMN6271A


I have not done much yet with the new backup radio, but trying the new Mic on my existing 7550e. Impressed with the receive audio quality on the new XP RSM.
I understand from Moto site that this Mic is supposed to be for APX radios and not for XPR, but given the seller was using them together and given threads like
I found here, it tells me this mic is supposed to ALSO work with the XPR7550 (though Moto does not state it so...)

XPR 7550 pairing to a IMPRES XP RSM Mic

Hi all, I have an XPR7550 I'm trying to get to work with my IMPRES XP RSM mic (NMN6271a). I know if I go on Motorola's website it doesn't list the 7550 as compatible but a local department has them as this exact same configuration. The orange button and programmable button 1 work as well as it...

forums.radioreference.com

My issue/question: I am able to transmit and receive (amazing RX audio) on my existing 7550e but there is a type of hiss/waterfall noise in the background of my transmissions. I do not get this noise when transmitting from built-in radio Mic (vs XP RSM) or from the existing handheld 4025A I already had.

I am suspecting some setting on radio but hopefully not something regarding the radio not really being "fully" compatible with this Mic.

Anyone familiar with this?

 

[MTS2000des]

The short answer is that the IMPRES RSMs are designed for the APX series. They integrate with the DSP on the APX side to perform advanced noise cancellation. The XPR is not an APX, has totally different DSP/firmware, and I suspect it doesn't play well with the IMPRES RSMs.
Two different product lines with different firmware for different purposes. While it MAY work, it isn't guaranteed to and may exhibit what you are experiencing.

 

[K2NEC]

I use the XP mic with a 7550e just about every day (firmware 2.09) with no issues. Whats your firmware and can you post a video of what the sound sounds like?

 

[KC1LKO]

More data points:

My original 7550e exhibiting the problem has firmware R02.22.03.1001 and codeplug 22.23.06

I programed my DMR ID and my local frequencies on the 2nd backup 7550e and it DOES NOT exhibit the problem so this gave me some hope. It was using firmware R02.20.01.0002 and codeplug 16.00.08

I tried for a while to match as much as possible of the config between both codeplugs, but kept getting the same results with the same microphone. I was using 3 radios to do this experiment. One was the listener and the 2 7550e radios were the transmitters. I would switch the hand microphones between.

I then updated the firmware on the new to me radio to match the one I already had: R02.22.03.1001 and codeplug 22.23.06

Now both radios exhibit the problem :-(

I will see if there is a newer firmware, but dreading having to start going backwards until there is one that makes this background his/running-water noise not be present on my transmissions. Too nice of a microphone to have this... might as well just get one like the 4025A I already have...

KC1LKO

 

[KC1LKO]

Two files inside this archive zip. One has 3x XM then 3x 4025 then 3x XM key downs with no audio. The 2nd file has a key down followed by my voice audio first on the XM then on the 4025 and I repeat it. Apologies for the iphone recording both, my voice direct as well as the 3rd radio receiving.

 

[TampaTyron]

What is your noise suppressor set to under General? It should be Basic or Off if using a noise canceling audio accessory. TT

 

[KC1LKO]

What is your noise suppressor set to under General? It should be Basic or Off if using a noise canceling audio accessory

Hello,
Thank you for the assist. I have tried it with disabled and with basic... I have new data since my last post... I do suspect much of this is related to AGC and/or Noise Suppression algorithms...

Perhaps I am missing something but no easy way to go back in firmware... I have for now held off on this given new discoveries... see below.

1. If I PTT and say nothing there is some type of background hiss/open faucet noise.
2. If I PTT and speak softly the noise gets louder. The radio / mic is trying to amplify my signal...
3. If I then say something much louder then the hiss/noise pretty much goes away... the radio/mic is trying to reduce my gain...
4. Once I speak loud the radio/mic seem to remember the AGC level and the noise does not come back until I PTT again.
5. What I am doing on my QSOs is to start saying something loud then people won't notice this noise... I still think there is a config or firmware incompatibility between this particular model of radio and particular Mic (ie. it was built for the APX apparently... not the XPR)

So this means that either this particular radio firmware is not aware of / in sync with the behavior of this particular mic or there is a setting that perhaps makes this work as you had suggested. I unfortunately have not yet determined what that setting is... once I suspected AGC/noise reduction I have tried a number of combinations of the following... perhaps I missed some as it was late last night. The suggesion given here makes a lot of sense, so perhaps I should make a table of options and try my tests again one by one.

- Noise Suppressor: Disabled, Basic, Enhance, Enhanced Auto (left it Enhanced as I originally had it)
- Fast Noise Suppressor Training Period: 10 (as it was set originally), Continuous (as I left it)
- Mic Distortion Control: On, Off
- Digital Mic AGC: On, Off

I ended up with the below, but not clear it is the 'correct' config.

Thanks again for the help/assistance

 

[nedflander]

I recently Just started to have a waterfall noise being heard by other radio users. Were you able to find a solution/settings to change in order for it to go back to normal?

 

[KC1LKO]

Were you able to find a solution/settings to change in order for it to go back to normal?

Negative. Not sure I will keep but have not tested further and not getting reports of noise not sure if due to new settings or using it in truck where I speak louder.

 

[TampaTyron]

What happens you you switch to basic noise suppressor? TT