tropiradio
Member
- Joined
- Mar 10, 2021
- Messages
- 178
So yesterday decided to experiment a bit with the Mic AGC in digital mode setting of the 7550e and 3500 (UHF) radios. I had some "low audio" complaints specially in noisy environments, so wanted to see if I could raise the speaker audio, and also eliminate the "hot first syllable" effect that is also happening once so often, and at least in my experience quite common when using the default audio settings.
Ideally I wanted to run the tests between two 3500 radios which is really the model of interest in this case, but one of my 3500 radios all of the sudden will no longer power on. It just sat unused for a couple of weeks and now it seems the power management chip has stopped working (more obvious fault no voltage present across the power switch anymore, or at any of the side switches for that matter), and I anticipate it will be a bi**ch to fix. But that is another story.
Anyway, back to the audio tests. First used the 3500 as a receiver, and to measure the level of audio from the speaker used a smartphone app called you guessed it "Decibel Meter" that has a peak hold for the highest level recorded. Smartphone about 1" from the radio. Yes I know it will be far from accurate in terms of real dB, but I only wanted to compare two audio levels under identical environmental conditions.
Set both radios to same simplex digital frequency, volume controls set to 12-oclock, Low Power Tx. All options at General->Audio Settings where turned off, as well as all alert tones, so they would not interfere with peak holding. Digital Mic AGC was set to 5, which will not come into effect until AGC is disabled. P2 was set to toggle AGC off/on.
Made a short recording of a 1-10 count on the Sound Recorder app of another phone to use as the audio source so it would be consistent between tests. Phone laid flat against the radio with speaker above microphone of radio. Distance between the Rx and Tx radios about 30ft, in separate rooms.
When I transmitted on the 3500 with AGC enabled, at the receiving end of the 7550e the decibel meter registered between 72-76dB peak level (did several tests). Then with AGC disabled (Mic Gain of 5 kicks in), the audio on the receiving end would then increase to 87-89dB. I could hear the receiving radio and indeed there was a noticeable difference in volume. So far so good.
Then transmitted with the 7550e to the 3500, but noticed that with both Mic AGC turned on, or off, strangely always got the same level, 89dB at the receiving end, and it actually sounded the same as well. There was absolutely no change, which I think is not what one would expect? I double checked again all the audio settings in both radios, and yes everything was turned off. So I do not understand why there was no change in audio level output at the receiving end when AGC was used or with it off and Mic gain set to 5. I would have anticipated to get a similar result as when the 3500 radio was used to transmit and there was a noticeable audio level difference between AGC on, or off.
So my question would be, could the 7550e have some sort of build in Tx audio leveling in the newer firmware? Or am I still missing some other CPS setting that could be causing this? The 7550e radio is R02.21, whereas the 3500 has older R02.09 FW.
Or might it be that one radio is "e" enhanced and the other not? I doubt it.
Ideally I wanted to run the tests between two 3500 radios which is really the model of interest in this case, but one of my 3500 radios all of the sudden will no longer power on. It just sat unused for a couple of weeks and now it seems the power management chip has stopped working (more obvious fault no voltage present across the power switch anymore, or at any of the side switches for that matter), and I anticipate it will be a bi**ch to fix. But that is another story.
Anyway, back to the audio tests. First used the 3500 as a receiver, and to measure the level of audio from the speaker used a smartphone app called you guessed it "Decibel Meter" that has a peak hold for the highest level recorded. Smartphone about 1" from the radio. Yes I know it will be far from accurate in terms of real dB, but I only wanted to compare two audio levels under identical environmental conditions.
Set both radios to same simplex digital frequency, volume controls set to 12-oclock, Low Power Tx. All options at General->Audio Settings where turned off, as well as all alert tones, so they would not interfere with peak holding. Digital Mic AGC was set to 5, which will not come into effect until AGC is disabled. P2 was set to toggle AGC off/on.
Made a short recording of a 1-10 count on the Sound Recorder app of another phone to use as the audio source so it would be consistent between tests. Phone laid flat against the radio with speaker above microphone of radio. Distance between the Rx and Tx radios about 30ft, in separate rooms.
When I transmitted on the 3500 with AGC enabled, at the receiving end of the 7550e the decibel meter registered between 72-76dB peak level (did several tests). Then with AGC disabled (Mic Gain of 5 kicks in), the audio on the receiving end would then increase to 87-89dB. I could hear the receiving radio and indeed there was a noticeable difference in volume. So far so good.
Then transmitted with the 7550e to the 3500, but noticed that with both Mic AGC turned on, or off, strangely always got the same level, 89dB at the receiving end, and it actually sounded the same as well. There was absolutely no change, which I think is not what one would expect? I double checked again all the audio settings in both radios, and yes everything was turned off. So I do not understand why there was no change in audio level output at the receiving end when AGC was used or with it off and Mic gain set to 5. I would have anticipated to get a similar result as when the 3500 radio was used to transmit and there was a noticeable audio level difference between AGC on, or off.
So my question would be, could the 7550e have some sort of build in Tx audio leveling in the newer firmware? Or am I still missing some other CPS setting that could be causing this? The 7550e radio is R02.21, whereas the 3500 has older R02.09 FW.
Or might it be that one radio is "e" enhanced and the other not? I doubt it.
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