Loud Environment - Digital Mode

[sammyg512]

We're using some DP4400's in a nightclub environment in Digital mode, which in a loud environment the sound transmitted sounds scrambled. When used in areas where there is no music, they sound fine. When used in Analog mode, they sound fine, and it sounds like a bandwidth problem. just wondering if there is anything that can be done in the codeplug to make them work better in a loud environment.

 

[RFI-EMI-GUY]

I did some testing of P25 CAI inside buildings on Miami Beach. The vocoder was IMBE. Inside of noisy bar, the radio transmissions were unintelligible. Sounded like classic intermodulation distortion. The vocoder could not make out a single voice. It was a jumble. I don't think there is any setting that will fix that. There are some AGC and gain settings, but anything you do will have a compromise elsewhere. Motorola released some sound cancellation for the high tier P25 radios, but as far as DMR, I doubt it.

 

[12dbsinad]

Stick to analog. For your application it'll work just fine, as you already found out.

 

[sammyg512]

Stick to analog. For your application it'll work just fine, as you already found out.

I've found no mater what settings i apply, Analog seems to work better in a loud environment. Could this be due to Compression on Digital Mode?

 

[RFI-EMI-GUY]

I've found no mater what settings i apply, Analog seems to work better in a loud environment. Could this be due to Compression on Digital Mode?

There are different forms of compression in digital mode. There is AGC and then there are algorithms to minimize the amount of data required to reconstruct the audio stream. The data compression is the big problem. The Vocoder makes a lot of decisions rather quickly and tends to have difficulty in parsing out and separate voices and also background noises. It is a big shortcoming. There was nothing inherently wrong with "wide band" (+/- 5.0 KHz) FM analog as the "Major" had intended.

 

[sammyg512]

I've created a seperate Zone for Analog channels, it seems from what people have been saying, plus some research, that there is a shortcoming with Digital Compression, meaning the messages in a loud nightclub environment are un-readable. In analog mode, there is no Digital Conversion, so more data can be transmitted.

 

[12dbsinad]

I've created a seperate Zone for Analog channels, it seems from what people have been saying, plus some research, that there is a shortcoming with Digital Compression, meaning the messages in a loud nightclub environment are un-readable. In analog mode, there is no Digital Conversion, so more data can be transmitted.

Basically, your human ear can pick out the human voice over background noise better then the vocoder can. When your receiving radio goes to decode the digital string it doesn't know the difference between you speaking in the radio and a loud band playing in the background. Now, with that said, top-tier P25 public safety radios have improved this tremendously with digital noise cancellation. But, your "cheap" DMR radios just don't cut the mustard like a 9K Harris or Motorola.

That's why I suggested sticking with analog if it works.

 

[K2NEC]

Your noise cancelling also heavily relies on which mic you are using. The radio mic won't perform as well as something like an INC RSM which is specifically designed for extreme noise cancelling

 

[tweiss3]

Funny this thread comes up when it did. I just experienced intermittent issues with DMR on a mix of Kenwood and Motorola radios this weekend at a music festival, no RSM, just internal microphones for the radios. A bunch of good things here to consider.

 

[Firebuff880]

Be sure to review your Audio Setting in the MOTOTRBO CPS. There are a number that can make a big difference in user experience.

 

[sammyg512]

Hi,
I'm having a little but of a problem getting my DP4400 and DP4400e radios to work well in a loud environment. On Analog mode, the voice seems much more clear, than when being used in Digital mode. The radios work great when in a quiet environment, but we would like to transition to using them in Digital mode.

I understand that when in Digital mode, there is a lot compression happening very fast, but wondering if there is any tricks to make voice more clear in a nightclub environment.

The current setup is:
Digital mic Gain: 12
VOX Sensitivity: L3
Privacy Enabled
Capacity Plus Enabled
AGC and Distortion control enabled
Noice Cancelling Off (This seems to make it worse for some reason)

I know its a big ask for a radio, but i'm looking for a way to make it clear in digital mode, in a very loud nightclub environment, so any config tips would be greatly appreciated.

Thanks in Advance.

 

[sammyg512]

I've had a play with the settings, and its a little bit better, this is what I have the audio profile set to. The reason i'd like to move them all to Digital, is so we can use the Privacy Function, as there is a lot of venues locally that use Analog Radios, and sometimes get interferance issues, on the frequancys OFCOM have allocated to me.

 

[celltech25]

That mic gain gonna kill ya

 

[FFPM571]

turn the mic gain down.. there is a setting in the CPS for loud environment Are you using Cap + ?

 

[sammyg512]

turn the mic gain down.. there is a setting in the CPS for loud environment Are you using Cap + ?

Heya, The radios are using Dual Capacity plus, i tried turning the mic gain down, but this made it even worse. The Loud Environment Setting is Enabled, and made a slight improvement. I currently have them using the 12.5Khz bandwidth mode, would changing this to a higher bandwidth help?

Cheers,
Sam

 

[FFPM571]

Heya, The radios are using Dual Capacity plus, i tried turning the mic gain down, but this made it even worse. The Loud Environment Setting is Enabled, and made a slight improvement. I currently have them using the 12.5Khz bandwidth mode, would changing this to a higher bandwidth help?

Cheers,
Sam

 

[FFPM571]

the bandwith has nothing to do with the audio settings.

 

[RFI-EMI-GUY]

Heya, The radios are using Dual Capacity plus, i tried turning the mic gain down, but this made it even worse. The Loud Environment Setting is Enabled, and made a slight improvement. I currently have them using the 12.5Khz bandwidth mode, would changing this to a higher bandwidth help?

Cheers,
Sam

OFCOM has determined the channel bandwidth in your license... You don't want to be splattering Mi6....

 

[RFI-EMI-GUY]

I've had a play with the settings, and its a little bit better, this is what I have the audio profile set to. The reason i'd like to move them all to Digital, is so we can use the Privacy Function, as there is a lot of venues locally that use Analog Radios, and sometimes get interferance issues, on the frequancys OFCOM have allocated to me.

Those venues also likely found analog works better. How about setting up two channels, one analog for normal stuff and the second digital encrypted for the secret squirrel stuff where you can duck into a broom closet if needed.

 

[alcahuete]

That mic gain gonna kill ya

turn the mic gain down.. there is a setting in the CPS for loud environment Are you using Cap + ?

He is using AGC. Adjusting the mic gain isn't going to do anything.