X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from securemail.ever-tek.com ([64.129.170.194] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTP id 6735799 for flyrotary@lancaironline.net; Mon, 17 Feb 2014 06:41:52 -0500 Received-SPF: none receiver=logan.com; client-ip=64.129.170.194; envelope-from=cbarber@texasattorney.net Received: from FCD-MAIL06.FCDATA.PRIVATE ([fe80::697f:d6aa:b87:78d8]) by FCD-MAIL05.FCDATA.PRIVATE ([fe80::809d:a06e:5913:452e%13]) with mapi id 14.03.0174.001; Mon, 17 Feb 2014 05:41:13 -0600 From: Chris Barber To: Rotary motors in aircraft CC: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Sound Level Testing Thread-Topic: [FlyRotary] Re: Sound Level Testing Thread-Index: AQHPK4MmEf3mgemh6kW/qPLjdr6c5pq5U0us Date: Mon, 17 Feb 2014 11:43:08 +0000 Message-ID: <560FA376-3662-4CFD-9D07-29A728BEAD5C@texasattorney.net> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: multipart/alternative; boundary="_000_560FA37636624CFD9D0729A728BEAD5Ctexasattorneynet_" MIME-Version: 1.0 --_000_560FA37636624CFD9D0729A728BEAD5Ctexasattorneynet_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable From how far away are these numbers? On my unmuffled pusher, IIRC, I was g= etting around 90db at about 20 feet. That being said, and I could be way of= f on distance, I will try to remember to retest, but I am using an iPhone a= pp. Chris. Sent from my iPhone 5 On Feb 16, 2014, at 19:56, "shipchief@aol.com" > wrote: Charlie; You are so correct! And I re-read that several times before I hit "send". 119.7 116.8 114.6 I'm using the first scale that the devise defaults to when started. 30-130 = DBa. I think it has a 80-130 scale, and I can select DBc too, so I'll do th= at. Sorry, but I'm glad you caught it and added the detail on A & C scale. Of course, those readings are averages, they were varying a bit and I had t= o pick a number. I hold it so the video cam can pick it up and I can review= it. -----Original Message----- From: Charlie England > To: Rotary motors in aircraft > Sent: Sun, Feb 16, 2014 5:39 pm Subject: [FlyRotary] Re: Sound Level Testing On 2/16/2014 4:09 PM, shipchief@aol.com wrote: I bought a Wensn 30-130 Decibel sound meter off fleabay. I use it to record= sound levels in front of my face in flight. I first tested my RV-8 after installing a turn down tip, but was also expe= riencing severe exhaust leaks from my turbo: 19.7 DBa After fixing the leak, I recorded 16.8 DBa Then I squeezed the turn down tip to a flattened rectangle opening, and rep= laced the lost area with 1/4" holes, which I bent to face backwards with a = Philips screwdriver. a Piccolo Pipe, as it's known. Kind of a cheese grater= for sound waves. Next reading: 14.6 DBa This is still to loud for my worn out ears, so I bought an Aeroturbine 2525= muffler, as described on this forum. I've been collecting 304 stainless pi= pe bend, ball joints clamps and hangers. I hope to get something cobbled to= gether this weekend. I, too, am looking forward to your report on how well it works. Suggest checking what's going on with your dB readings, though. 16 dB is qu= ieter than a bedroom at night, & likely inaudible to those of us who have b= een flying for a decade or two. Realistic levels expected in the cockpit of= a homebuilt will be between 85 dB (pretty good, but still loud) & 120 dB (= loud rock concert levels and painful to most of us). I'd also suggest using the C scale instead of the A scale. The A scale is v= ery commonly used, but it presents a very distorted view of the actual soun= d level. It radically filters the low end of the spectrum, and to a lesser = extent, the high frequencies, as well. It will mask the level of your actua= l noise exposure, especially at the low end of the noise spectrum. Charlie --_000_560FA37636624CFD9D0729A728BEAD5Ctexasattorneynet_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
From how far away are these numbers?  On my unmuffled pusher, IIR= C, I was getting around 90db at about 20 feet. That being said, and I could= be way off on distance, I will try to remember to retest, but I am using a= n iPhone app. 

Chris. 

Sent from my iPhone 5

On Feb 16, 2014, at 19:56, "shipc= hief@aol.com" <shipchief@a= ol.com> wrote:

Charlie;
You are so correct! And I re-read that several times before I hit &quo= t;send".
119.7
116.8
114.6
I'm using the first scale that the devise defaults to when started. 30= -130 DBa. I think it has a 80-130 scale, and I can select DBc too, so I'll = do that.
Sorry, but I'm glad you caught it and added the detail on A & C scale.
Of course, those readings are averages, they were varying a bit and I = had to pick a number. I hold it so the video cam can pick it up and I can r= eview it.
-----Original Message-----
From: Charlie England <ceengland= 7@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sun, Feb 16, 2014 5:39 pm
Subject: [FlyRotary] Re: Sound Level Testing

On 2/16/2014 4:09 PM, shipchief@aol.com wrote:
I bought a Wensn 30-130= Decibel sound meter off fleabay. I use it to record sound levels in front = of my face in flight.
 I first tested my= RV-8 after installing a turn down tip, but was also experiencing  sev= ere exhaust leaks from my turbo: 19.7 DBa 
After fixing the leak, I recorded 16.8 DBa
Then I squeezed the turn down tip to a flattened rectangle openin= g, and replaced the lost area with 1/4" holes, which I bent to face ba= ckwards with a Philips screwdriver. a Piccolo Pipe, as it's known. Kin= d of a cheese grater for sound waves. Next reading: 14.6 DBa
This is still to loud for my worn out ears, so I bought an Aeroturbine= 2525 muffler, as described on this forum. I've been collecting 304 stainle= ss pipe bend, ball joints clamps and hangers. I hope to get something cobbl= ed together this weekend.
I, too, am looking forward to your report on how well it works.

Suggest checking what's going on with your dB readings, though. 16 dB is qu= ieter than a bedroom at night, & likely inaudible to those of us who ha= ve been flying for a decade or two. Realistic levels expected in the cockpi= t of a homebuilt will be between 85 dB (pretty good, but still loud) & 120 dB (loud rock concert levels an= d painful to most of us).

I'd also suggest using the C scale instead of the A scale. The A scale is v= ery commonly used, but it presents a very distorted view of the actual soun= d level. It radically filters the low end of the spectrum, and to a lesser = extent, the high frequencies, as well. It will mask the level of your actual noise exposure, especially at = the low end of the noise spectrum.

Charlie
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