Den fredag den 28. juni 2013 00.10.31 UTC+2 skrev Eric Jacobsen:
> On Thu, 27 Jun 2013 13:59:13 -0700 (PDT), langwadt@fonz.dk wrote:
>
>
>
> >Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott:
>
> >> A while ago I posted a question about how to extract pitch information
>
> >>
>
> >> from the messy sound of an engine. It was for an iPhone app I have
>
> >>
>
> >> developed which displays the RPM of an engine based on the sound it
>
> >>
>
> >> makes. Vladimir and other suggested autocorrelation as used in pitch
>
> >>
>
> >> detection in speech. Thanks, guys! After a long time struggling with
>
> >>
>
> >> various ad hoc ways to qualify peaks in the FFT and match them up with
>
> >>
>
> >> harmonics of the fundamental pitch of the engine, the autocorrelation
>
> >>
>
> >> method beats them all by a long shot. I finally got it all
>
> >>
>
> >> implemented into my app, which also displays a real-time graph of the
>
> >>
>
> >> autocorrelation function. I have tested it on lawnmowers, string
>
> >>
>
> >> trimmers, generators, motorcycles, industrial earthmoving equipment,
>
> >>
>
> >> and single-engine airplanes. In almost every case the graph was clear
>
> >>
>
> >> and the RPM calculation was solid. I wish I had known about this
>
> >>
>
> >> three years ago when I first released my app. I could have avoided a
>
> >>
>
> >> lot a bad reviews. Thanks again. This is a new tool in my toolbox.
>
> >>
>
> >>
>
> >>
>
> >> Robert Scott
>
> >>
>
> >> Hopkins, MN
>
> >
>
> >kinda related or at least interesting :)
>
> >
>
> >http://www.youtube.com/watch?feature=player_embedded&v=MtrSNFjkGdU#at=97
>
> >
>
> >
>
> >-Lasse
>
>
>
> Nice example. ;)
>
>
>
> I've seen that guy's vids before and he's really good at mimicing the
>
> sounds.
>
>
>
> Also, looking forward to the new engines next year!
>
yes it will be really interesting, getting the KERS, TERS and engine to work
together and not least provide power and braking in a way that the drivers
can control will be incredibly complex
The 2014 Le Mans LMP1 has the potential to be even more technically interesting, They will have a fuel flow limit plus a fuel allocation per lap, but the rest is much more free, no limits on cubic capacity, number of cylinders, variable geometry turbos etc. and up to 8MJ ERS per lap
-Lasse
Reply by Eric Jacobsen●June 27, 20132013-06-27
On Thu, 27 Jun 2013 13:59:13 -0700 (PDT), langwadt@fonz.dk wrote:
>Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott:
>> A while ago I posted a question about how to extract pitch information
>>
>> from the messy sound of an engine. It was for an iPhone app I have
>>
>> developed which displays the RPM of an engine based on the sound it
>>
>> makes. Vladimir and other suggested autocorrelation as used in pitch
>>
>> detection in speech. Thanks, guys! After a long time struggling with
>>
>> various ad hoc ways to qualify peaks in the FFT and match them up with
>>
>> harmonics of the fundamental pitch of the engine, the autocorrelation
>>
>> method beats them all by a long shot. I finally got it all
>>
>> implemented into my app, which also displays a real-time graph of the
>>
>> autocorrelation function. I have tested it on lawnmowers, string
>>
>> trimmers, generators, motorcycles, industrial earthmoving equipment,
>>
>> and single-engine airplanes. In almost every case the graph was clear
>>
>> and the RPM calculation was solid. I wish I had known about this
>>
>> three years ago when I first released my app. I could have avoided a
>>
>> lot a bad reviews. Thanks again. This is a new tool in my toolbox.
>>
>>
>>
>> Robert Scott
>>
>> Hopkins, MN
>
>kinda related or at least interesting :)
>
>http://www.youtube.com/watch?feature=player_embedded&v=MtrSNFjkGdU#at=97
>
>
>-Lasse
Nice example. ;)
I've seen that guy's vids before and he's really good at mimicing the
sounds.
Also, looking forward to the new engines next year!
Eric Jacobsen
Anchor Hill Communications
http://www.anchorhill.com
Reply by ●June 27, 20132013-06-27
Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott:
> A while ago I posted a question about how to extract pitch information
>
> from the messy sound of an engine. It was for an iPhone app I have
>
> developed which displays the RPM of an engine based on the sound it
>
> makes. Vladimir and other suggested autocorrelation as used in pitch
>
> detection in speech. Thanks, guys! After a long time struggling with
>
> various ad hoc ways to qualify peaks in the FFT and match them up with
>
> harmonics of the fundamental pitch of the engine, the autocorrelation
>
> method beats them all by a long shot. I finally got it all
>
> implemented into my app, which also displays a real-time graph of the
>
> autocorrelation function. I have tested it on lawnmowers, string
>
> trimmers, generators, motorcycles, industrial earthmoving equipment,
>
> and single-engine airplanes. In almost every case the graph was clear
>
> and the RPM calculation was solid. I wish I had known about this
>
> three years ago when I first released my app. I could have avoided a
>
> lot a bad reviews. Thanks again. This is a new tool in my toolbox.
>
>
>
> Robert Scott
>
> Hopkins, MN
> On 6/12/2013 10:31 AM, Robert Scott wrote:
>> On Tue, 11 Jun 2013 12:05:00 -0700 (PDT), Kevin Neilson
>> <kevin.neilson@xilinx.com> wrote:
>>
>>> Also, doesn't a 2-cycle engine have a fundamental pitch that is the
>>> same as the RPM (or RPS), whereas a 4-cycle, 1-cylinder engine
>>> would have a pitch half that of the crankshaft rotation?
>>
>> Part of the setup of our app is the selection of an engine
>> configuration, which specifies the factor to be used when converting
>> between Hz and RPM. That factor can be whatever the user determines
>> is appropriate.
>
> Well you could learn acoustic signatures and then do classification
> automatically. That would be really interesting thing to develop.
>
>
> Vladimir Vassilevsky
> DSP and Mixed Signal Designs
> www.abvolt.com
>
It's also open ended.
--
Les Cargill
Reply by Vladimir Vassilevsky●June 17, 20132013-06-17
On 6/12/2013 10:31 AM, Robert Scott wrote:
> On Tue, 11 Jun 2013 12:05:00 -0700 (PDT), Kevin Neilson
> <kevin.neilson@xilinx.com> wrote:
>
>> Also, doesn't a 2-cycle engine have a fundamental pitch that is the
>> same as the RPM (or RPS), whereas a 4-cycle, 1-cylinder engine
>> would have a pitch half that of the crankshaft rotation?
>
> Part of the setup of our app is the selection of an engine
> configuration, which specifies the factor to be used when converting
> between Hz and RPM. That factor can be whatever the user determines
> is appropriate.
Well you could learn acoustic signatures and then do classification
automatically. That would be really interesting thing to develop.
Vladimir Vassilevsky
DSP and Mixed Signal Designs
www.abvolt.com
Reply by Tauno Voipio●June 16, 20132013-06-16
On 16.6.13 1:32 , Rick Lyons wrote:
> Hi Tauno,
> Did you ever have to parachute out of your airplane,
> land your plane on the highway, or anything exciting like
> that?
>
> [-Rick-]
Nothing so drastic.
The heaviest I have met was a pheasant in flight
at about 100 ft above the runway on takeoff. I
managed to roll the plane so that the bird did not
hit the wing, but it crashed with my landing gear.
A pheasant is so large that it swayed the small
Beech 150 very noticeably. The tower controller
said: 'You seem to hit something', and I returned
to the airport. My only concern was if the remains
of the bird are in my brake, but it was somewhat
higher on the landing gear. There was a band of
feathers, some of which I stapled to the bird strike
report. The airport maintenance found the remains
of the bird, so we could verify the diagnosis.
I have a civilian stomach, so I do not like to
fly upside down with a parachute on my back. With
most small airplanes, it is far more safe to make
a spot landing than to abandon the plane.
--
-Tauno
Reply by Rick Lyons●June 15, 20132013-06-15
On Wed, 12 Jun 2013 11:15:04 +0300, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:
[Snipped by Lyons]
>
>The traditional piston engines are opposing cylinder (boxer),
>which complicates the sound a little more. I had an opposing-
>cylinder direct-drive engine (Continental TSIO360) in my
>previous airplane, with a three-blade propeller. The engine
>exhaust noise is pretty well muffled, but the propeller is
>pretty loud at take-off power (36 inch radius, 2750 rpm).
>
>In my current airplane, things are different: The engines
>are modified Mercedes turbo diesels (Austro Diesel AE300)
>with 1:1.69 gearing and max rpm 2300 at the propeller.
>The sound is much quieter, despite of two engines.
Hi Tauno,
Did you ever have to parachute out of your airplane,
land your plane on the highway, or anything exciting like
that?
[-Rick-]
No. 6: "Where am I?"
No. 2: "In the Village."
No. 6: "What do you want?"
No. 2: "Information."
No. 6: "Who are you?"
No. 2: "I am the new No. 2."
No. 6: "Who is No. 1?"
No. 2: "You are No. 6."
No. 6: "I am not a number. I am a free man!"
Reply by rickman●June 15, 20132013-06-15
On 6/11/2013 1:11 PM, Kevin Neilson wrote:
> That's interesting. Why does the autocorrelation work so much better? Don't all the harmonics still show up in the autocorrelation graph?
In an autocorrelation the harmonics add into the fundamental while in an
FFT all of the frequencies are distinct.
--
Rick
Reply by Robert Scott●June 14, 20132013-06-14
On Tue, 11 Jun 2013 04:08:32 GMT, no-one@notreal.invalid (Robert
Scott) wrote:
>>Is it already available in the app store?
>
>Only the crummy FFT-only version is there now. The autocorrelation
>version is only on my development phone so far. I plan to submit the
>update to app store in the next few days and then Apple will have to
>review it before they let it go live.
The update was just approved today and version 2.0 with the
autocorrelation method is now live in the app store ("Engine RPM").
Robert Scott
Hopkins, MN
Reply by Eric Jacobsen●June 12, 20132013-06-12
On Wed, 12 Jun 2013 11:15:04 +0300, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:
>On 12.6.13 9:21 , Eric Jacobsen wrote:
>> On Wed, 12 Jun 2013 09:01:20 +0300, Tauno Voipio
>> <tauno.voipio@notused.fi.invalid> wrote:
>>
>>> On 12.6.13 12:48 , glen herrmannsfeldt wrote:
>>>
>>>> Well, one response I remember seeing was that properler RPM was
>>>> more useful than engine RPM.
>>>>
>>>> Could be interesting if the exhaust pipe was close to the
>>>> propeller, as there might be some cross (mixing) terms.
>>>>
>>>> -- glen
>>>
>>>
>>> In a propeller airplane, it is common that the propeller noise
>>> is louder than the exhaust noise. Each blade creates a spiral-
>>> formed wake pressure front. At take-off power, the blade tips
>>> run pretty near the speed of sound. This is a design limitation,
>>> which limits the direct-drive engine RPM to below 3000 rpm.
>>
>> And that's why many engines aren't direct drive. Reciprocating
>> combustion engines make more power for the same displacement as the
>> rpm increases, so letting the engine's rotating assembly turn much
>> faster than 3000 rpm allows it to make more power for the same size
>> engine without pushing the propeller blade tips too fast.
>>
>> So that with, say, an even number of cylinders and an odd number of
>> blades, or something like that, can make for some oddball expectations
>> in the acoustic behavior.
>>
>>> In type certification it is required to have an instrument
>>> for propeller RPM. This is a safety requirement to protect
>>> against overspeed.
>>
>> Yup.
>>
>> http://www.youtube.com/watch?v=yLLG2_ErvJs
>>
>>
>> Eric Jacobsen
>> Anchor Hill Communications
>> http://www.anchorhill.com
>>
>
>The traditional piston engines are opposing cylinder (boxer),
>which complicates the sound a little more. I had an opposing-
>cylinder direct-drive engine (Continental TSIO360) in my
>previous airplane, with a three-blade propeller. The engine
>exhaust noise is pretty well muffled, but the propeller is
>pretty loud at take-off power (36 inch radius, 2750 rpm).
>
>In my current airplane, things are different: The engines
>are modified Mercedes turbo diesels (Austro Diesel AE300)
>with 1:1.69 gearing and max rpm 2300 at the propeller.
>The sound is much quieter, despite of two engines.
>
>--
>
>-Tauno
>
Nice!
Turbos always help keep the exhaust noise quiet, too.
Eric Jacobsen
Anchor Hill Communications
http://www.anchorhill.com