Gentex helmet volume control

Little Bird · May 20, 2017

Just got a Gentex Sph 4b helmet and thinking I need a volume controller. I see I could get an inline one or buy a new cord set with volume controller knob.

Has anyone gone either way and have suggestions or recommendations good or bad?

Thanks

avbug · May 20, 2017

I just bought an Alpha from Pro Flight Gear. I ordered it with the volume control. Most of the time, the audio panel or radio volume will be fine; when working with others in the cockpit, being able to set the radios and then adjust your own personal use is beneficial.

This is especially true if someone wants it quieter. It's better to turn the radios to a higher volume then use individual intercom and headset/helmet volume controls to neck the volume down, than to start with a quiet volume and try to turn it up using the headset or intercom.

It's also easier sometimes to make a quick adjustment at the helmet, then to reach out for individual panel-mount knobs.

Little Bird · May 20, 2017

Yeah the volume when I speak is deafening. None of the audio panel knobs fix this so think a volume controller is essential.

Did you get an inline controller or is there a knob on your helmet that you turn?

Gomer Pylot · May 21, 2017

Sidetone is adjustaable in the radio, but you need an avionics tech to do it for most radios. You have to at least pull it out of the console, and maybe open the case. But if it's very loud compared to the received volume, you should try to get it adjusted. They should be near the same level.

Little Bird · May 21, 2017

Thanks GP.

I had thought about this however when I use a regular headset there is no deafening volume when I speak, so I thought the problem must be specific to my helmet.

avbug · May 21, 2017

Sidetone is adjustable at the individual radio, but be careful because it's not a single adjustment as it appears, and it is an avionics action, not a pilot action.

Is the audio volume such that you're being blasted out when an external transmission is heard on the headphones (eg, ATIS)? Is it louder to hear yourself than it is to hear other transmissions?

Adding a volume control for the headset, whether inline or on the helmet body (mine is in the helmet body) will control all audio input to the helmet. If the helmet is okay with external transmissions but too loud with the sidetone (hearing yourself speak), then adjusting the volume down with a helmet-mounted volume control may make the sidetone tolerable, but will neck down the incoming received transmission, and you'll hear it softer or weaker or quieter, depending on your view.

Are you using a boosted dynamic microphone (amplified carbon)? What type microphone and set up do you have with your helmet? Are you using a military helmet, microphone, and plug in a civilian system? Do you have other helmets in the same system, and are they doing similar things? A mix of microphone types? Impedence mismatch can cause all kinds of audio problems in an intercom or audio panel, especially when different crew in the same aircraft are using different microphones, helmets, and headsets.

Little Bird · May 21, 2017

Thanks Avbug.

I adjusted the radios and the internal pilot/pax coms to an acceptable level. But when I press the PTT to speak externally I am deafened.

I don't have the helmet with me here now so can't say what type mic it is. However when I bought the helmet it had been converted to civilian coms. I am the only helmet user but other pilots use DC, Bose X and Zulu Lightspeed headsets with no issues. When I return to the hangar I will check on the mic type.

avbug · May 21, 2017

When you have more than one type in use in the aircraft, it can cause problems. I see this most when a combination of passive and ANR headsets are in use on the same intercom system.

I suspect from your description that you're using an amplified dynamic mic, which is identifiable as a larger mic than what's found on most civilian DC type headsets. The smaller electret type mic will work best. If you have a larger, rounded mic, especially with a square shaped black or green box behind it or part of it on the wire boom side, you may have an amplified mic, and that can cause problems.

You might try using a different mic on your helmet to see if this solves the problem. Also plug your helmet into a different aircraft. It's rare that each will be adjusted the same; see if the problem persists. Do you know which earphones you have for your helmet? You should have 300 ohm.

Little Bird · May 23, 2017

The mic on the helmet is an Acousticom Electret 5700-CA.

I used the helmet on our 2nd heli yesterday with no problems. Heli radios adjusted normally and my voice normal volume when triggering the PTT. And I just plugged into our 3rd machine while on the ground and everything seems normal there too.

Unsure of what the speakers are.

So from my tests I would say it is a sidetone issue with the original aircraft? Or could it be just a conflict due to the many headsets used?

avbug · May 23, 2017

Try your helmet in the offending aircraft again, without anyone else plugged in. Problem still exists, yhen you have either an intercom system adjustmentbproblem, or a sidetone issue.

Does your problem occurvwhen hearing yourself on the intercome, or only when transmitting?

Little Bird · May 26, 2017

So I plugged myself back into the offending aircraft without anyone else.

Same problem. Deafening volume when I push the PTT only. Intercom is normal.

avbug · May 26, 2017

So I plugged myself back into the offending aircraft without anyone else.
Same problem. Deafening volume when I push the PTT only. Intercom is normal.

That suggests a sidetone adjustment. This occurs on one particular radio, or all of them?

Try someone else's headset or helmet in the offending aircraft, see what happens.

avbug · May 28, 2017

What type radios are in use, and what type audio panel?

Little Bird · May 29, 2017

Sorry, I've been out in the bush with not much internet access. It occurs using both radios. I have the only helmet but there's no problems with the headsets. I've actually gone on leave for a few days so I'll answer the radio/audio panel question when I return.

avbug · June 3, 2017

The helmet isnt from Gibson & Barnes by chance, is it?

Garmin, technosonic, or wulfburg radio?

CEP or ANR installed?

This may be an issue of low resistance with i ternal components to the headset. The reason I ask if it's a Gibson and Barnes product is because of an unusually high number of problems with their helmets.

I've been working through a very similar problem with an associate the past few days. His chief problem is occurring when he keys the mic on the FM radio (technosonic), but is also happening on a Garmin stack with a garmin audio panel. User sidetone wasnt installed. I loaned him my helmet for a flight, and the problem vanished. We did microphone swaps, only a slight improvement. He has a backup helmet without the ANR installation that he will try, but a helmet diagnostic did show several isses with respect to resistance in the helmet, almost certainly directly due to components and installation by Gibson and Barnes.

Little Bird · June 27, 2017

Helmet not from Gibson & Barnes, well at least not bought by me. Was bought online. Garmin radios and no CEP or ANR. I haven't been flying the other machine that gave me the problems initially for a while. The machines I do fly now don't give me any problems at all. All little gremlins there...

Reminds me of my time in Alaska using a Bose X headset. The rest of the pilots has DC or Zulus. Every machine I'd use my Bose would start off fine and then the volume in my ears would just slowly start decreasing until I couldn't hear a thing, both over the radios and intercom. Pax and other pilots could hear me fine. Throughout the summer everyone thought I was just a whining so-and-so until right at the end of the season, a relief pilot back from his summer of fires passed through, did a couple tours and complained of exactly the same problem! Ahhh sweet redemption... Never could figure out the problem though.