[arm-allstar] web-based audio level meter

[Doug Crompton]

Justin,

Audio levels are always an issue. We have future plans in our new channel
driver to do auto leveling which should be nice. The problem with making it
viewable as you describe is that node operators can set their levels with
existing tools but others that are not node sysops but use the nodes have
no way to set levels. This is where an auto leveling feature would really
be nice. Another big issue is levels from other modes like Echolink which
are all over the place due to the nature of how the audio is created.
Computer microphones are not a good way to create audio!

Also education is a big factor here. I can't tell you how many times I tell
users to talk right into their handhelds especially some of the Chinese
handhelds. If you are 6 inches away it is way down in level. Any microphone
should be held close to your mouth. Side talk it to eliminate breath noise
but close.

While the simpleusb-tune-menu RX audio display is OK for setting levels one
method I often use is the iaxrpt bargraph display. It is a pretty accurate
indication of level and if someone is pegging to the end of the display
they are more than likely causing distortion. Shooting for a 95% level on
peaks is good.

Another problem we are faced with is audio level perception. This is based
on many factors including the persons voice characteristics, the end to end
equalization, etc. This causes someone to sound louder or softer when their
actual measured levels are correct. So it is hard to make everything
totally correct with the wide range of hardware we use. The most important
thing is to not distort. Nothing sounds worse than a clipping audio signal.



*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*

On Sat, Feb 25, 2017 at 10:39 PM, "Justin Reed via arm-allstar" <
arm-allstar at hamvoip.org> wrote:

> Group,
>
> I'm just putting this out here because there are lots of knowledgeable
> folks here.
>
> I'm curious if anybody would know how to integrate an audio level meter
> into the v1.5 node so that radio/node users could view their live audio
> level on a web page. I'm basically looking for something like the NorCal
> DMR folks had on their website.  I'm constantly battling users with audio
> levels all over the place and it would be beneficial if I could point them
> to a website that shows where their level falls.
>
> Thanks,
> Justin
>
>
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