Lightspeed Delta Zulu
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- Boatguy
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Lightspeed Delta Zulu
This could be sort of fun. I bought the new Lightspeed Delta Zulu because it has an equalization function to help correct hearing loss. You take a test, similar to what you do with an audiologist, and then the equalizer built into the headset compensates for your loss of hearing. I took the test and it was similar to what I got from an audiologist, my high frequency hearing has dropped off considerably!
Today was the first time I flew with the new headset and it was a bit weird. It definitely boosted the highs and ATC was noticeably clearer. But when climbing out, 100% power, raising the flaps, etc my engine sounded strange. I was kinda spooked because I've only flown it about half an hour since the Austro 600hr service (new flywheel, new high pressure pump, etc.) and a complete prop overhaul. The plane seemed to perform just fine, but what was I hearing?
Then it hit me, I'm hearing what I previously did not hear! I think my engine always sounded this way, I was just blissfully ignorant. At least I hope that's what's going on.
If anyone else gets this headset, and the test reveals significant gaps in their hearing, please post your reaction here. Are you hearing new sounds from the engine? Does your plane sound a little different than with your old headset?
Today was the first time I flew with the new headset and it was a bit weird. It definitely boosted the highs and ATC was noticeably clearer. But when climbing out, 100% power, raising the flaps, etc my engine sounded strange. I was kinda spooked because I've only flown it about half an hour since the Austro 600hr service (new flywheel, new high pressure pump, etc.) and a complete prop overhaul. The plane seemed to perform just fine, but what was I hearing?
Then it hit me, I'm hearing what I previously did not hear! I think my engine always sounded this way, I was just blissfully ignorant. At least I hope that's what's going on.
If anyone else gets this headset, and the test reveals significant gaps in their hearing, please post your reaction here. Are you hearing new sounds from the engine? Does your plane sound a little different than with your old headset?
- CFIDave
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Re: Lightspeed Delta Zulu
Delta Zulu's hearing equalization will enhance high frequencies (to compensate for hearing loss) *only* for sounds generated by your audio panel (e.g., ATC, intercom, or music).
This would NOT include engine sounds that acoustically leak through the headset ear cups, despite the headset's ANR trying to cancel out this noise (ANR is normally most effective in cancelling out bass frequencies, not highs).
Perhaps Delta Zulu's improved ANR does a better job of cancelling out engine noises -- so that you're actually hearing LESS engine noise than with other headsets. But I don't see how the equalization function could affect your perception of engine sounds.
This would NOT include engine sounds that acoustically leak through the headset ear cups, despite the headset's ANR trying to cancel out this noise (ANR is normally most effective in cancelling out bass frequencies, not highs).
Perhaps Delta Zulu's improved ANR does a better job of cancelling out engine noises -- so that you're actually hearing LESS engine noise than with other headsets. But I don't see how the equalization function could affect your perception of engine sounds.
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- Boatguy
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Re: Lightspeed Delta Zulu
Of course, what was I thinking? Thank you for pointing that out!CFIDave wrote: Fri Nov 11, 2022 2:57 pm Delta Zulu's hearing equalization will enhance high frequencies (to compensate for hearing loss) *only* for sounds generated by your audio panel (e.g., ATC, intercom, or music).
This would NOT include engine sounds that acoustically leak through the headset ear cups, despite the headset's ANR trying to cancel out this noise (ANR is normally most effective in cancelling out bass frequencies, not highs).
Perhaps Delta Zulu's improved ANR does a better job of cancelling out engine noises -- so that you're actually hearing LESS engine noise than with other headsets. But I don't see how the equalization function could affect your perception of engine sounds.
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Re: Lightspeed Delta Zulu
Boatguy wrote: Fri Nov 11, 2022 5:12 am
If anyone else gets this headset, and the test reveals significant gaps in their hearing, please post your reaction here. Are you hearing new sounds from the engine? Does your plane sound a little different than with your old headset?
I don't have the headset (yet), but it's quite possible you are hearing the result of processing artifacts introduced by the Active Noise Reduction system. While ANR systems generally provide excellent noise reduction, they do not process or attenuate equally across the audio band due to a range of factors.
As audio frequencies within ambient the noise spectrum increase, the corresponding wavelengths decrease quite dramatically, and because ANR systems often use an array of small microphones to detect external ambient noise, small phase discrepancies can result in 'destructive interference' artifacts occurring. As a result, an ANR system can never generate the precise 'antiphase' signal required to cancel out all external noise frequencies equally, and so this results in some residual 'coloration' distortion which is added electronically back into the headphone's audio feed.
The Lightspeed Delta Zulu will no doubt have its own unique ANR and mechanically induced sound colorations, but because it can now also effectively compensate for some types of (moderate) hearing loss, those inherent colorations are going to sound especially apparent when compared to other aviation ANR headsets.
Last edited by RookieFlyer on Fri Nov 11, 2022 8:04 pm, edited 1 time in total.
- Boatguy
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Re: Lightspeed Delta Zulu
Thank you!RookieFlyer wrote: Fri Nov 11, 2022 7:39 pm The Lightspeed Delta Zulu will no doubt have its own unique ANR and mechanically induced sound colorations, but because it can now also effectively compensate for some types of (moderate) hearing loss, those inherent colorations are going to sound especially apparent when compared to other aviation ANR headsets.
- Chris
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Re: Lightspeed Delta Zulu
AVweb just dropped an interesting (if a little long) video talking about the Delta Zulu. They discussed the ANR improvements, and Paul remarked that the difference in engine noise was noticeable to him as well.
I'm adding one of these to my Xmas list in case anybody is looking for something to give me this year.
I'm adding one of these to my Xmas list in case anybody is looking for something to give me this year.

- Boatguy
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Re: Lightspeed Delta Zulu
Upon further investigation, the Zulu 3 has the ANC microphone inside an ear cup. However, the DZ has a second microphone on the outside of the ear cup which means the ANC is listening to the engine noise and presumably compensating for what it hears in general cockpit background noise which of course includes the engine.CFIDave wrote: Fri Nov 11, 2022 2:57 pm Delta Zulu's hearing equalization will enhance high frequencies (to compensate for hearing loss) *only* for sounds generated by your audio panel (e.g., ATC, intercom, or music).
I'll make a leap and speculate that the equalization is applied to both the ANC, and to any primary sound source (i.e., panel audio, BT music, etc.).
Their FAQ also acknowledges that the mic sensitivity is a little different and includes instructions for how to adjust the mic gain on both Z3 and DZ.
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Re: Lightspeed Delta Zulu
What good would that do? Wouldn't applying equalization for hearing loss (i.e., turning up the treble, since people lose high frequency hearing as they age or are subjected to too many loud sounds) to the ANR anti-noise signal make engine noise more noticeable, not less?Boatguy wrote: Mon Nov 14, 2022 6:03 pmI'll make a leap and speculate that the equalization is applied to both the ANC, and to any primary sound source (i.e., panel audio, BT music, etc.).
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- Boatguy
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Re: Lightspeed Delta Zulu
We're going to now attempt to delve into their ANC algorithm. My simple understanding is that they use an out of phase signal to cancel the noise, but I'm not an acoustic engineer.CFIDave wrote: Mon Nov 14, 2022 7:15 pmWhat good would that do? Wouldn't applying equalization for hearing loss (i.e., turning up the treble, since people lose high frequency hearing as they age or are subjected to too many loud sounds) to the ANR anti-noise signal make engine noise more noticeable, not less?Boatguy wrote: Mon Nov 14, 2022 6:03 pmI'll make a leap and speculate that the equalization is applied to both the ANC, and to any primary sound source (i.e., panel audio, BT music, etc.).
What I can say is that my engine sounds different.
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Re: Lightspeed Delta Zulu
I got the Delta Zulu for Christmas too and noticed a louder engine sound when using the equalization. I have not tried it without the equalizer yet. BTW, can anybody hear anything at the 12,000 Hz level
on the hearing test? The higher frequencies feel "brighter" to me. The carbon monoxide sensor is nice.
I was comparing it to my Zulu 3's.

I was comparing it to my Zulu 3's.
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