MOTOTRBO Firmware audio quality

[w0en]

I have seen reports of better digital audio quality after a Firmware upgrade to 1.07 and beyond. Does anyone know if this is a repeater or subscriber function or both? Most of subscriber radios here are 1.06 as are repeaters. I am having repeaters gradually upgraded to latest 1.08. Could I expect better quality with only the repeaters upgraded or does everything need to be done?

[wavetar]

You need to upgrade the field units as well.

[boteman]

I can't comment on whether you will notice an improvement over what you have, but I can say that after performing some radio tests and hearing users on a ConnectPlus 1.1 system that the audio is PHENOMENAL. These were brand new radios so they have to be running 1.08 or whatever the latest is.

The audio from portable to portable through the repeater sounded much like a public address mic with wide frequency response, good presence, and crisp sibilant sounds. I think they could do well to tailor the audio more towards traditional communications-grade 300-3000 Hz shaping and provide some companding to compensate for the shouters and the whisperers, but otherwise the audio rocks.

My Motorola dealer contact at the customer site claims that the audio through the Connect Plus controller is better than other TRBO variants, but I don't see how that can be. The A-D and D-A converters lie in the subscriber units while the repeater just shovels bits hither and yon. Anyway, it was impressive to me. Maybe he was inadvertently referring to the difference between older firmware versions and the newer one required for ConnectPlus 1.1

Speaking of A-D converters, I noticed the same splattering distortion on the TRBO portables that I have heard on XTS public safety portables when the user hit the mic too hard. Sounds awful and I'm surprised that Mother Mo hasn't provided some sort of ALC in the analog mic input circuitry to prevent overdriving the digitizer. I mean, even the ancient Modcom consoles had a glimmer dimmer in them to act as mic ALC fer cryin out loud!

[escomm]

Yes but when you say phenomenal... you are comparing this to previous iterations of digital, correct? I don't know why the audio would sound any different on capacity plus vs standalone or connect plus, perhaps it's something to do with the option board, but the radios I have running connect plus sound just as bad as ever, down to the sock in the mouth quality

[boteman]

It's becoming clearer to me that the delivered audio quality is dependent on how hard the user hits the mic. Apparently you have to drive the digitizer into its sweet zone. Mumblers sound more mumbly, shouters get that breaking-up splattering effect that I mentioned above and it sounds nasty. Somewhere in the middle they sound loud and clear.

My gripe is that both IMBE and AMBE+2 have HUGE variances in dynamic range. They really need some sort of compression or companding action on their input to reduce the dynamic range. However, when the user hits the mic at the proper level the codec does quite well on the receive end. I suppose that if you're looking for that great MICOR blue chip audio then you won't get it from these digital boxes. Those days are gone forever I'm afraid.

[JRayfield]

Is AGC enabled in digital mode on all of your radios?

John Rayfield, Jr. CETma

[boteman]

Not my radios, since I'm not the radio shop. I have no idea. Sounds like something that should default to "ON" in the CPS if it actually helps.

If it is disabled, then I seriously doubt the customer is going reprogram several hundred radios just for that. Which is why I would expect the proactive radio shop to elect this choice from the get-go to do a proper job of it.

[wavetar]

I find the AGC in the TRBO platform to be more hindrance than help at times. In my experience it does virtually nothing to lower 'hot' audio levels hitting the mic, and it overdrives anything beyond even a moderate voice level to the point of making the audio muffled. I've made the suggestion to enable a programmable limit on the AGC gain, like what can be set in the Astro/25 radios. A good speaker/mic with noise reduction can help out a lot, compared to the internal mic on the portables.

Same goes for accessories such as remotes...the audio levels need to be turned way down compared to analog in order to have the audio sound very good at all.

Kenwood NexEdge radios do a far better job, and give the shop techs a lot more adjustments to play with. You can even lower the sensitivity of the tx audio input in the accessory connector to help things like remotes sound better.

[torontokris]

wow thats an interesting feature on the NEXEDGE, would be nice to have on a TRBO radio for sure

Kenwood NexEdge radios do a far better job, and give the shop techs a lot more adjustments to play with. You can even lower the sensitivity of the tx audio input in the accessory connector to help things like remotes sound better.