Axiom Audio Dropouts & Threshold. Try This!

[Steve Herschbach]

I need a little help here. Many people including myself have had an issue with audio drop outs using the Garrett Z-Lynk wireless headphones with Axiom. Z-Lynk works fine with other Garrett products, so I think it’s just an interference issue that Z-Lynk has with PI specifically.

Recently I ran into something more. I was using the Axiom with no headphones at all and was having some audio drop out. I thought that was odd, maybe a speaker problem, so plugged in my wired headphones. Still happened.

Now, I  have been treating the Axiom threshold control as if it is a normal threshold control. But I always thought something was weird about it. First, nothing really seems to happen unless you turn it way down, like single digits or even negative numbers. Second, to my ear the audio has always seemed slightly disconnected from the actual all metal channel, like it is less a true all metal threshold and more like a reference threshold.

Long story short on a whim I increased the threshold. And a funny thing happened. Not only did the drop outs stop happening, but the machine overall ran much smoother. I had to lower the volume a bit to compensate, but wow, what a difference.

For me the magic was happening with a threshold of 20, far higher than I have normally set the Axiom threshold. Used to be around 6 - 8. I am now pretty well convinced the Axiom threshold control is acting more like a squelch control, and instead of needing to be turned down as low as possible like a normal threshold control, actually needs to be set higher to obtain a more stable threshold. Setting it to low can cause the audio not to just get quieter but to actually break up.

This may or may not help out with the wireless drop outs, but I do think now we have maybe been mixing up two separate issues. Some people who think the wireless is dropping out may instead be experiencing what I saw, drop outs caused by a low threshold setting. It’s not impossible that this might even help with the wireless issue by boosting the signal strength somehow. I’m doubtful but who knows. Like I said, something different than a normal threshold control going on here, or so it seems to me.

If anyone cares, please give this a try with some experimentation and report back. Thank you!

[Craig Peer]

Interesting. I've been using the Garrett wireless headphones and haven't had any problems with them, but I'll try this. 

[Steve Herschbach]

12 hours ago, Craig Peer said:

Interesting. I've been using the Garrett wireless headphones and haven't had any problems with them, but I'll try this. 

I find it interesting indeed that there is anyone at all that has used the Garrett wireless system as supplied with the Axiom and who has not experienced issues with audio dropping out. Of course people not having problems don't complain but I was under the impression this issue was universal with Axiom users. Now I am wondering if that is not the case at all, that maybe it's only people having the problem speaking up. Anyone else out there using the supplied MS-3 headphones with the Axiom and not having momentary audio drop outs? Not asking about anything but Axiom, mind you.

If that is true, the follow-up has to be - why not? Why would some of us being having the problem and some not? I have used multiple Axiom and MS-3 combos and every one did it. Could it be the threshold setting thing that I started this thread out with makes a difference in the wireless, and it is people habitually turning the threshold setting down below the default that are having the problem?

Well, I just got a brand new Axiom to replace the completely beat up first off the production line model I was using the last couple years and I will be digging into this some more with the latest hardware.

[abenson]

Come to think of it I had a time when the audio was dropping out on the speaker when I was doing some testing. I just figured the audio was trying to connect to the headphones because it stopped after a about 20 seconds. I haven't ever experienced dropout with plug in headphones.

[GotAU?]

I never experienced dropouts using a Bluetooth transmitter and the Torus speaker on my Axiom, even while using low threshold values. I will have to play around with it more, and will try those higher threshold values.
 

The dropouts also seem to mostly go away when I keep the built-in receiver in the MS-3 headphones  (I believe it’s the side with the buttons) on the same side of my body as the detector (I switch the detector from my right to left arm often to avoid arm fatigue and flip the headphones around accordingly).

[Knomad]

Interesting observation and thought Steve, I have been busy and it is hovering around 100 degrees here so have not been out for a while.  BUT I do tend to keep a very low threshold, the drop outs seemed different than the borderline threshold instability from being set too low, but maybe not, I will test it when I can. 

I do know there is something unusual about going total no threshold and Max sensitivity in really bad ground as I documented in an earlier video, so I am convinced the Axiom is using some kind of Threshold / Filter, so that may be what is going on, by occasionally the filter getting behind or out of sync with the audio..! 

[RedDirtDan]

I have this drop out on MS3 all the time - I'm left handed and so I have to wear the headphones backwards so that the (what I think) "receive" side is on the same side as the Axiom itself. Interesting about the threshold information - I'll try this when I get my broken shaft clamp fixed!

[CarsonChris]

I started running the threshold at 20 earlier this year. I found it to be better from 18-20 as far as stability. I will use the headphones with them touching above my ears to cut back on sound bombardment. I think it didn't have dropouts while turned up but didn't pay attention to it. 

[GotAU?]

I went out prospecting last weekend with my Axiom during a break and had no issues with dropouts when I wore my headphones turned so that the side with the on/off button was on the same side of my body as the detector. I ran it with the smaller mono coil on high sensitivity,  and low as well as high threshold values. I only experienced dropouts when I switched the detector to the left side of my body without turning the headphones. I believe the main problem with the signal dropping out is that it’s easily blocked by objects such as my head and body.