Audio – (LUFS) – Loudness, Levels & Quality

NEW – May 14, 2025: Updated and Improved Audio Meter (LUFS visual meter) is now available.

October 2023 & into 2025: Audio quality over the network is in the pits! As more users come aboard the network fewer seem to have any concern for their poor audio levels or quality. We have tried to help users improve their audio, but it appears to be a losing effort. Don’t be a loser!

OK so maybe that opener is too harsh…or offensive. But we want to impress upon our members, that audio quality and level are both important, especially so in the DMR arena. So don’t be that guy in the restaurant talking loudly on his cell phone…oblivious (or simply uncaring) to how his voice is affecting the folks around him. Also, low audio is problematic too but less offensive. Both hot or cold should be addressed…and we have the tools to help you get get the best audio out over the air.

Over the air reports of audio are very subjective and are course at best or better than nothing. While 2 hams in conversation can set their own volume controls to compensate for the other’s incorrect audio level, the 3rd and 20th hams listening cannot. Everyone must listen that audio differential or worse, to all the hot distorted audio. At the very minimum OTA reports require 3 hams, the 3rd to try to report on the first 2. Known as “diving for the volume pot”, this approach does not work well.

DMR Audio has 2 components that are important: Level and Quality, more similar to “loudness”. This is no different than analog; be it HF or FM, but possibly more important to get correct as the vocoder (voice coder from analog to digital). Vocoders are less tolerant of poor audio.

PNWDigital has Audio Streaming, online LUFS Meter and the Parrot (echo test) and an Audio Test talkgroup. These tools support our own nets when they are active and a few other talkgroups when there are no active nets.

Our LUFS meter supports Audio Test, Washington 2 and PNW Regional 2 full time, except during weekly nets carried on timeslot 2. The weekly nets currently supported are: the Cascade Coffee Net, the Not-A-Net Gathering, the Oregon Net and the Happy Hour Net.  This list may change at any time so check our Events Calendar for the latest information.

Please use our tools. Don’t rely completely on over-the-air reports as they are subjective at best and likely not correct…or certainly not the best method to get your audio dialed in.

Audio Tools in the Quiver

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LUFS (visual audio level) Meter

NOTE: Portions of this page are out of date. Here’s the text of Dave W7NCX’s post until further updates: Vu Audio Leveling, Version 2

A few years ago, we designed the Vu Audio Levels page (Vu Version 1 or VuV1) as an accessible tool for system users to visualize audio levels.  Sometimes it worked well, and some found it inaccurate.  From this, came the idea of adding the pre/post bumpers to the Parrot echo service.  This allowed users to compare their playback audio to that of Duff, WA7BFN, who graciously recorded the announcements for us.  That also had challenges.  Some radios have Receive Audio Leveling, negating the audible differences if levels were off, and it also didn’t quantify the change needed, or allow easy comparing of various levels.

Today, we are announcing Vu Audio Leveling Version 2 (VuV2).  Here’s a few of the features:

“Loudness” based upon a standard

One “Loudness” result, rather than “Average” and “Peak” values

VuV1 measured the audio levels by calculating the RMS, with some smoothing over peaks, and some filtering of silence.  VuV2 uses, LUFS – Wikipedia,  which is an ITU standard used by many broadcast services, including TV, Radio, and podcast services.  “Integrated VUFS” has good statistical correlation to the VuV1 Average level, and will become our new Vu calculation.  We are hopeful it will more accurately measure audio than the method used with VuV1. 

With Vu V1, it was never really clear if someone should set their levels based upon the average or peak levels, or maybe some combination of the two.  Vu V2 simplifies that choice.  It has been running in the background, and our current average Integrated LUFS is -29.   The initial ranges are as follows:

•                 Very low               Below -35
•                 Low                        -35 to -31
•                 Normal                 -31 to -27
•                 High                       -27 to -23
•                 Very high             Above -23

The visual meter is also redesigned to be a linear bullseye, based upon the above ranges, with red-yellow-green-yellow-red areas.  Our target values are different from those of the various broadcast services, just as they have variances themselves.  If we all adjust towards -29, our system will sound better, and many of us are already there, as -29 is our average value. 

If you scroll down to the bottom of the LUFS meter page, you will find this additional information shown below.

• Our system average is shown in top row, an average level of about -29 dB. The closer that everyone is to our average minimizes the need to adjust volume while listening.
• The meter displays between -39 and -19 LUFS, with the green range between -31 and -27 LUFS.
• The meter updates every 30 seconds and is connected to a C-Bridge manager that monitors 9998 Parrot, 9999 Audio Test, and our nets.

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Try saying the following passages on the Parrot:

“Sadly, Sam Sold Seven venomous Serpents to Sally and Syrus in San Francisco.”

The other method to stress the audio is to say:

“Mic Check, Mic Check..Check Check Check, Four Four Fooouuuurrrrrr.”

These passages played back to you via the Parrot may reveal that you are too hot, talking into the mic port are otherwise, on the high or harsh end of the audio range.  Soft audio while less of an issue, makes it difficult for the listeners to listen, but would be preferred if you cannot achieve a normal ALQ. It also sets up for volume roulette where the listeners must manage each audio level actively or get blasted after turning up for that last low audio talker. This is a nasty mess during check-in nets.

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Additional Considerations

DMR has a very wide dynamic range of audio. The wide levels of audio coming across the repeaters and networks makes it difficult to hear the soft users as hot audio causes users to turn down their volume.  Conversely listening to soft users will position other users to get blasted at random times.  Routine or background monitoring of the various TRBO networks is made more difficult and this page is an effort to identify some middle ground…if that is even possible.

Another issue in audio levels is the AGC’s tendency to produce super hot (PIERCING) audio levels briefly at the beginning of a voice encoding.  It is quite obnoxious and makes it difficult to monitor the traffic on the network, especially when listeners are in a mixed-mode environment of family, work or TV viewing, etc.  Less of an issue but still valid, is simply the wide range of user voices differences and how the mic is positioned relative to the mouth.  Also significant though short term or random, are issues such as breath puffs across the face of the mic, wind and ambient noise.

Taken together, it really means that each and every user must make an affirmative effort to test and adjust their radio settings and speaking style to enable the best audio “loudness” possible.

First Published: December 10, 2021 Last Updated: 11 hours ago by Mike – NO7RF

Views: 1718