High frequency sound in cockpit

[Wizard1393]

Hi all,

 

There's this really high frequency tone in the cockpit of the A-10C.

It's driving my tinnitus mad. It does not go away with "hear as in helmet".

Where can I find the cockpit sounds so I can make my own sound mod to remove this?

Edited December 30, 2019 by chrisofsweden

[Wizard1393]

EDIT: Found the sound file causing it: "Avionics_AC_400Hz_US.wav"... thank the lord.

[CaptHawk]

Did this just start? No issues here with the latest update. I'll check out the sound file you mentioned. At 400hz its the end of the mid bass beginning of the mid range and is most sensitive to our ears. I do audio recording/mixing and yes, that frequency range can be fatiguing taken in large doses over time. That would bug the $#%@ out of me flying around in the A10C if somehow a 400hz tone was generating in the background, no wonder it's bugging your tinnitus.

 

Sent from my SM-G930W8 using Tapatalk

[Moafuleum]

I'm not at my computer right now but can you load the file into your favourite fft plugin and see if there is maybe an additional frequency present that is maybe not intended?

[Harzach]

 

There are several other tones present in the sample, with one particularly nasty one between 4.7 - 4.9kHz. That would definitely agitate one's tinnitus.

Edited January 1, 2020 by Harzach

[ac5]

I also have tinnitus but the only sound which annoyed me was the

"rumbling noise", also at idle. Solution:

 

https://forums.eagle.ru/showthread.php?t=230832

[CaptHawk]

I believe the Op has already mentioned:

 

"EDIT: Found the sound file causing it: "Avionics_AC_400Hz_US.wav"... thank the lord."

 

Problem solved

 

 

 

Sent from my SM-G930W8 using Tapatalk

[jamesgmills]

Thank you for this. I'm new to the A-10 (and DCS as a whole!) and getting rid of this sound has made it much more enjoyable to play. Well done on tracking down the culprit and sharing it!

Edited January 7, 2020 by jamesgmills

[Wizard1393]

Np! I just had to. As someone said above, there's more than one "tone" or "noise" in that file. To me it's one of the highest ones that bother me the most. You know, a sort of electrical sound that almost "sound" like a CRT TV when it's turned on. High frequency, not 400hz as the file name seems to reflect.

[Wizard1393]

 

There are several other tones present in the sample, with one particularly nasty one between 4.7 - 4.9kHz. That would definitely agitate one's tinnitus.

 

Yeah, that's definitely the one.

[lobo]

Sorry, couldn't here it over the noise of my case fans. ;)

[eaglecash867]

I do audio recording/mixing and yes, that frequency range can be fatiguing taken in large doses over time. That would bug the $#%@ out of me flying around in the A10C if somehow a 400hz tone was generating in the background, no wonder it's bugging your tinnitus.

 

Yup. It also makes it much more difficult to stay awake if you didn't get enough sleep the night before. :smilewink: Its a constant in most western cockpits, but sometimes the avionics work I'm doing in there doesn't require inverters so I can shut them off. Eastern aircraft don't have that issue because their inverters generally run at 50Hz, which is far less noticeable.

[jamesgmills]

Is that sound new with the new 3d cockpit?

No, this sound was present prior to the new cockpit. Here's a 2013 post complaining about it, too. As with most high pitches, it probably bothers some people more than others. Some may not even hear it.

 

Its a constant in most western cockpits, but sometimes the avionics work I'm doing in there doesn't require inverters so I can shut them off.

Sorry that I'm not parsing what you're saying clearly enough... Are you saying that the sound is accurately modeled/simulated?

 

Given the choice between accurate simulation and annoyance, I'll personally put up with the annoyance in order to get a taste of the real thing, though I wouldn't blame anyone who wants to silence this particular tone as a little 'quality of life' improvement. If the sound is erroneous, though, it would be nice to get it cleaned up and truer to the real deal, especially if that makes it friendlier to the ear.

Edited January 9, 2020 by jamesgmills

[eaglecash867]

Sorry that I'm not parsing what you're saying clearly enough... Are you saying that the sound is accurately modeled/simulated?

 

Given the choice between accurate simulation and annoyance, I'll personally put up with the annoyance in order to get a taste of the real thing, though I wouldn't blame anyone who wants to silence this particular tone as a little 'quality of life' improvement. If the sound is erroneous, though, it would be nice to get it cleaned up and truer to the real deal, especially if that makes it friendlier to the ear.

 

Just checked to make sure nothing has changed since the last time I played weeks ago, and its still nearly 100% accurate. The only reason I say "nearly 100%" is because you don't hear the changes in pitch that you normally hear when doing things like caging the standby gyro and rotating the baro knob on the altimeter. Other than that, it pretty much sounds like a real cockpit. :D

[Harzach]

No, this sound was present prior to the new cockpit. Here's a 2013 post complaining about it, too. As with most high pitches, it probably bothers some people more than others. Some may not even hear it.

 

 

It's not so much a "high pitch" issue as it is that the center frequency is close to that of the center frequency of human hearing (~4kHz). Those who suffer tinnitus or other hearing damage/loss often have an accompanying hyperacusis (sensitivity to sound). A loud sound near the frequency that humans hear best (4kHz) will be very annoying or even uncomfortable for them.

[Shimmergloom667]

It's not so much a "high pitch" issue as it is that the center frequency is close to that of the center frequency of human hearing (~4kHz). Those who suffer tinnitus or other hearing damage/loss often have an accompanying hyperacusis (sensitivity to sound). A loud sound near the frequency that humans hear best (4kHz) will be very annoying or even uncomfortable for them.

 

But the Inverter runs at 400 Hz, not at 4 kHz, unless I am awfully mistaken...

[eaglecash867]

But the Inverter runs at 400 Hz, not at 4 kHz, unless I am awfully mistaken...

 

It is 400Hz, which is the main hum, but there is a higher frequency component to the real sound too, which pretty much sounds like the CRT TV that Chris described. I'm one of the last of the dinosaurs in my shop who knows how to do bench repairs, but inverters aren't on our capabilities list, so I've never had one opened up to know what the higher frequency component of the sound comes from. Since it sounds a lot like the high voltage (1500 volts) transformer in a transponder, my guess would be that its noise from magnetorestriction in the transformers inside the inverter, or possibly the rotor windings in the AC servo-driven instruments in the cockpit.

[Shimmergloom667]

Either way - I can hear it, but I don't even notice it anymore after a few seconds. Interesting, that it is such an annoying sound for other people, wouldn't have thought that.

[eaglecash867]

Either way - I can hear it, but I don't even notice it anymore after a few seconds.

 

Me neither. I'm actually happy to hear that noise to begin with. Makes it feel more real. :)

[Harzach]

But the Inverter runs at 400 Hz, not at 4 kHz, unless I am awfully mistaken...

 

See the spectrogram and reply I posted above.

[eaglecash867]

See the spectrogram and reply I posted above.

 

Very cool! Didn't take a detailed look at this before. So, it looks like we have 1.2, 1.6, 2.0, 2.4, 2.8, 4.8, and 7.2 KHz; all multiples of 400Hz, so it looks like the 400Hz inverter is generating lots of different harmonics. Thanks for posting that spectrogram! Now I know where the extra frequencies are coming from. :D