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Topic Title: AGC automatic gain control and Dragon
Topic Summary:
Created On: 05/26/2021 05:14 PM
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 05/26/2021 05:14 PM
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Some of my microphones have the option to check AGC (automatic gain control) in Additional Sound Settings.


Dragon (in my case, DPI 15 15.6) also has a checkbox for similar feature in the "manage dictation sources" section, where you can check or uncheck the "automatically adjust Microphone level as I speak" checkbox.


I did some testing to figure out what difference it makes if AGC is checked or unchecked in Dragon and Windows in various combinations.

To test, I dictated text into Notepad and all the various cases of AGC being checked, and then I played the audio back using the "play that back" command so I could hear what Dragon had heard me say.

I tested the four possible cases:

  • case 1: AGC enabled in Windows and Dragon
  • case 2: AGC enabled in Windows, disabled in Dragon
  • case 3: AGC enabled in Dragon, disabled in Windows
  • case 4: AGC disabled in both Dragon and Windows


 throughout all the tests, I watched the microphone volume in Windows settings, because sometimes it would adjust down from 100 to 70. Whenever it did adjust down, I would change it back to 100 and do another test.


I got the following results:

- in case 1, the playback volume is loud

- in cases 2, 3, and 4, the playback volume is quieter and it is the SAME.

it seems strange that the playback volume in case 4 would be the same as case 2 and case 3.

It's also surprising that in case 1, the playback volume is louder. I assumed that Dragon would either ignore Windows AGC entirely and do automatic volume adjustment within Dragon. But what seems to be happening is that the sound of my dictation gets louder when AGC is enabled in both places, as though gain is being added to the microphone by both Windows and Dragon. 

Note: This is using a headset that does not have a gain knob built in, nor any special sound drivers that would allow me to adjust again manually. The only way I have of manipulating the gain is through the microphone volume bar in Windows settings, and then the AGC button in Windows, and the "automatically adjust volume..." checkbox in Dragon. 

I feel like I get the same level of accuracy with dictation regardless of whether AGC is turned on or where it is turned on.


 I'm wondering...

  • What's going on behind the scenes on a technical level?
  • What is best practice for getting good dictation?  
  • Do you have AGC checked on your microphone in Windows and/or in Dragon? Why?



Dragon Professional Individual v15.6. Windows 10. Knowbrainer 2017.

 05/26/2021 06:53 PM
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Lunis Orcutt
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Joined: 10/01/2006

Nuance doesn't focus on playback volume so we recommend ignoring it. This is probably a moot point because you're going to manually make this change to suit your playback taste. Nuance's only concern is microphone input. Having said that, microphone input unnecessarily takes control over the sound output level; until you manually change the level. AGC was deployed in Dragon Ver. 13 but not made the default setting until Ver. 15. The idea is to give Dragon the right to change your input volume on the fly. If, for whatever reason, you speak louder or lower than usual, AGC compensates. If you forget and leave your microphone on your desk, Dragon will increase the input volume so that you can almost get away with it but not quite.

If you enable your computers AGC, you might experience louder playback but it is irrelevant. Microphone input is your only Dragon concern and when using the Dragon default AGC setting, it will override your computer volume input setting.

The entire process is meant to be automatic and not tinkered with but many end users experience lower accuracy with Dragon's default AGC. Some microphones may not work ideally with AGC either. This is why Nuance started including the option to turn off AGC in Ver. 15.61 but not earlier releases. We have switched back and forth looking for the ideal setting but it makes no difference for many of us. Those of us who have been using Dragon for a while may see no difference because we don't typically change our microphone distance or volume level but many physicians have to disable AGC and run the Microphone Check because it can make a significant difference in Medical dictation accuracy. Some DPI 15 users also have to disable AGC. It doesn't appear to be an exact science so we recommend everyone try both options. If both settings make no difference, go with AGC because it is more forgiving and will allow you to change out your microphone without having to rerun the Microphone Check. We don't recommend checking the AGC in Windows because, as previously noted, Dragon takes care of this for you.


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