---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Thu 06/30/16: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:48 AM - Re: Noise Reduction (Gary Aman) 2. 06:17 AM - Re: Noise Reduction (John Hauck) ________________________________ Message 1 _____________________________________ Time: 05:48:36 AM PST US From: Gary Aman Subject: Re: Kolb-List: Noise Reduction Rick,what rpm does your prop turn when the vw is at 3600.You still running the Valley redrive unit? > On Jun 29, 2016, at 11:04 PM, Rick Neilsen wrote: > > We had a discussion a while ago about ways to reduce noise in our Kolbs. I just flew tonight and tried to evaluate how quiet it is now with my current headsets. I fly with Bose QC-20 noise canceling ear buds under my Sigtronics over the ear headset with the Headset noise canceling kit. I plug my Bose ear buds into my intercom to hear and my Sigronics microphone into my intercom to speak. At cruise it is like sitting in my living room with a truck idling out side the house. I can hear the low tones of the engine in the back ground but I can hear voices on the radio at normal indoor volumes. When I talk, the intercom opens the microphone so I can hear more noise till the squelch cuts it off. > > When I started the engine tonight I had the Bose ear buds in my ears but turned off so I could hear the engine sounds clearly. Then I turned on the Bose noise canceling and that cut the idle engine noise to a reasonable level. Then I put the Sigtronics headset on with the Sigtronics noise canceling off. This cut out most of the high frequency noise. Then I turned on the Sigtronics noise canceling kit. Not much change. In the air with my big VW turns 3200 RPM at app 60% cruise power. If I turn the Sigtronics noise canceling kit off I can hear the engine sounds better so I turn if off from time to time to check the health of the engine. My engine turns only 3600 at full power (it is loud!) so most of the noise is lower frequency which noise canceling does a pretty good job of canceling. > > Rotax engines turn more RPMs creating a higher frequency noise which noise canceling doesn't work as well to cancel. My understanding is that higher frequencies are easier to reduce with passive aviation head sets but I don't know for sure. I other words I don't know how well my setup will work for you. > > Anyway it sure is nice not having my old ears ringing after every flight. > > Rick Neilsen > Redrive VW Powered MKIIIC ________________________________ Message 2 _____________________________________ Time: 06:17:37 AM PST US From: "John Hauck" Subject: RE: Kolb-List: Noise Reduction You are right, Rick N. ANR is designed for lower frequency noise, like much slower turning engines than the Rotax two and four cycle engines. The 912ULS easily overpowers my ANR headset. Already deaf, I am right on the edge of not being able to understand communications with others. With a passive headset, I am lost. Larry C's set up works well. If I was going to be doing a lot of long cross country flights in the future I'd probably go with Larry's set up or spend the money and go with Rick N's set up. There was a time I could hear well with a passive David Clark. I lost my hearing in VN 50 years ago. Got a chance to go to Army helicopter school two years later. Had to cheat a bit to pass the flight physical. Never had a problem being able to hear and understand communications with a flight helmet, even though I could not pass the hearing test. Right now my ears are ringing louder than my Rotax. ;-) Don't think my hearing loss will ever ground me. There is no requirement to have a radio in my MKIII. I am legal, with a radio, to fly into non-towered airfields in the US. Don't plan to fly back to Canada, so I good there. john h mkIII Titus, Alabama From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Rick Neilsen Sent: Wednesday, June 29, 2016 10:05 PM Subject: Kolb-List: Noise Reduction Rotax engines turn more RPMs creating a higher frequency noise which noise canceling doesn't work as well to cancel. My understanding is that higher frequencies are easier to reduce with passive aviation head sets but I don't know for sure. I other words I don't know how well my setup will work for you. Anyway it sure is nice not having my old ears ringing after every flight. Rick Neilsen Redrive VW Powered MKIIIC ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kolb-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Kolb-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kolb-list Browse Digests http://www.matronics.com/digest/kolb-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.