How much can be reverse engineered from sound ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 17, 2019, 10:10:10 pm
content: given the task to make the machine that made this amazing sound, what wound the best science of today do ? or i suppose they would guess it's an f1 engine and just start there

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 17, 2019, 10:11:28 pm
content: i wonder what it looks like on an o-scope

author: windsmurf
author_rank: Frequent Contributor
timestamp: May 18, 2019, 12:57:06 am
content: Quote from: lordvader88 on May 17, 2019, 10:11:28 pmAudacity

author: Audioguru
author_rank: Super Contributor
timestamp: May 18, 2019, 03:04:37 am
content: The dinky little V6 engines on today's F-1 cars do not sound like that. But there are many stupid noisy cars and motorcycles in my city or they drive through my city and they sound deafening like that.I wonder why many cars make almost no noise?

author: Brumby
author_rank: Unknown
timestamp: May 18, 2019, 04:11:05 am
content: Very simple. It's the exhaust system.Some years ago I spent a couple of years in a "sea-change" job working for a mechanic. He was an approved examiner for several things, including noise pollution.One day, a Ferrari came in having been reported for noise and even at idle, the sound level nearly cracked the limit - but it did sound sweet. The exhaust system was a custom/after market job worth more than $10K and it was suggested he refit the factory exhaust. He did this and came back - but it failed the sound test. Turns out that the factory system had vanes that could provide a more direct (and thus noisier) path for the exhaust gases when high performance was required, instead of the more circuitous and quieter path for sedate motoring. This is what killed his chances of passing the test.He went away once more and had these vanes disconnected from the control system and fixed in position for the circuitous path. This time, the vehicle passed the test - just - but it sounded like and asthmatic dog with a hessian bag over its head getting strangled. The sound was just "wrong" in every way imaginable. It did not belong to a Ferrari.And it was all affected by just the exhaust system

author: Bud
author_rank: Super Contributor
timestamp: May 18, 2019, 05:08:52 am
content: I must be missing something...What is so beautiful in this sound? To me it sounds as a boring gigantic mosquito

author: floobydust
author_rank: Super Contributor
timestamp: May 18, 2019, 05:24:59 am
content: Some car makers actually hire sound engineering firms to do the exhaust design, to make the sound unique and have signature harmonics.Automobile exhaust systems are resonant systems. The exhaust manifold, main pipe, resonator, catalytic converter, muffler - all can be modelled using electrical equivalence i.e. RLC properties. A cylinder fires, a pressure wave propagates down the pipe and can "tug" other cylinder's pressure pulsations.To get good scavenging with minimum back pressure, and a resonance matching the engine's needs to get a flatter or peaky power curve is the goal.

author: Brumby
author_rank: Unknown
timestamp: May 18, 2019, 06:23:52 am
content: If you want to understand just how much the exhaust systemdoes, try driving a vehicle with bits of it missing...The abovementioned mechanic did LPG conversions and sometimes there would be a need to alter the path of the exhaust system to get around the LPG tank. I was the one usually chosen to drive these vehicles over to the exhaust place - and let me tell you, you get a REALLY good first hand lesson in the accoustic output of even the most moderate engine - especially when under load. As a result, my driving in these situations wasextremelyconservative - but there was still a bridge over a railway that had a steep approach and the noise was intense.Sometimes the only bits of the exhaust still attached were the manifold, engine pipe and catalytic converter. BIG noise! (and, yes, I was constantly looking in all directions for any police interest - which I never encountered, thankfully)

author: CJay
author_rank: Super Contributor
timestamp: May 18, 2019, 06:56:49 am
content: Dunno Bud, maybe different people like different things?A recording of the sounds makes my neck tingle, I know from having been in the pits when F1 cars are being started and warmed up that the sound and feeling makes my whole spine tingle and makes me smile.A lot.@floobydust, I think all car manufacturers who build vehicles with IC engines have sound engineers these days, there were pretensions to engine 'note' in pretty much all of the 'performance' model brochure hype when I was looking at buying a car last year, it almost reads like audiophool reviewers wrote some of them.The resonant thing has long been known about by people who design performance cars and bikes (have a feeling the bike guys were on the money first), 2 stroke motorcycles have made use of it since forever and there are some amusing stories of Suzuki and Honda 'borrowing' technology from European bike manufacturers way back in the 1950s, I'd think it was known about even earlier than that by some.

author: james_s
author_rank: Super Contributor
timestamp: May 18, 2019, 07:10:43 am
content: I think one of the nicest sounding engines I've heard is the Bristol Centaurus sleeve valve radial. It's a unique sound with no valve noise.

author: CJay
author_rank: Super Contributor
timestamp: May 18, 2019, 07:48:54 am
content: All those big old aero engines are fantastic, scary as all get out when starting, the flames from the exhaust when you're sat in what is essentially a fairly small aluminium box filled with ammunition and fuel...

author: ebastler
author_rank: Super Contributor
timestamp: May 18, 2019, 07:50:51 am
content: Quote from: lordvader88 on May 17, 2019, 10:10:10 pmWhile I am impressed from an engineering perspective that one can build a macroscopic machine which runs reliably at that high rpm (well, at least reliable for the duration of a race), I personally hate the sound.If you want to enjoy that sound at home, I recommend buying a model aircraft engine. Better check with the neighbors first.

author: Rerouter
author_rank: Super Contributor
timestamp: May 18, 2019, 08:15:08 am
content: The acoustics is from the pipe length and shape, At a guess you would want to analyse what harmonics and frequencies your chasing, compare to what your starting with, and then model a pipe/cavity to amplify or suppress the harmonics to reflect what you are chasing. once you have that down pat it would be a matter of getting it manufactured, as it would likely be a complex composite shape it may require metal sintering, or just a whole bunch of metal working.

author: tszaboo
author_rank: Super Contributor
timestamp: May 18, 2019, 08:32:31 am
content: Quote from: Bud on May 18, 2019, 05:08:52 amYes, unfortunately F1 doesnt sound that all that good anymore with the recent changes.Typically on the qualifications day, they have Porsche supercup, Formula 3000 and other races, those sound better than F1. To bad, it just feels like just watching a bunch of random people driving around, unlike F1. No offense to those random people.

author: David Hess
author_rank: Super Contributor
timestamp: May 19, 2019, 11:51:58 pm
content: Quote from: floobydust on May 18, 2019, 05:24:59 amYep, it sounds like typical tuned headers without any sort of baffle plus the Doppler shift from high speed.

author: amyk
author_rank: Super Contributor
timestamp: May 20, 2019, 02:12:57 am
content: Quote from: Bud on May 18, 2019, 05:08:52 amSame, I like something deeper and more "grumbly":

author: Psi
author_rank: Super Contributor
timestamp: May 20, 2019, 03:43:00 am
content: I always liked the feels of this sound.It starts at 1:00

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 20, 2019, 03:57:48 am
content: Quote from: Brumby on May 18, 2019, 06:23:52 amHad my exhaust replaced recently, had to limp around town with nothing on while they were getting parts in. Even the weedy engine in my Toyota sounds like a hotrod* when it's loud and open like that.*A hotrodded lawnmower, to be more honest / accurate.Also quite a difference; the previous system I had, was welded from pipes and parts. In particular it was missing a mid-line resonator. Never quite sounded right. (This time around, it's all aftermarket or OEM parts, close enough to original. Sounds about right.)Also a little surprising how much, and how little, difference can be made from little leaks here or there. Rusted out pipes tend to get loud, and add a rougher sound with more hiss (modulated hiss -- turbulence on the pulses). Sound from underneath or behind the vehicle tends to carry pretty well. OTOH, leaks in the engine bay don't seem to do much, presumably as the sound is forward-facing and reasonably well absorbed and scattered by everything in there. (They weren't able to seat the downpipe quite right so I had this going on, before getting it re-checked.)Tim

author: digsys
author_rank: Unknown
timestamp: May 20, 2019, 04:30:23 am
content: PPFFTTTTTTT These guys have it all sown up !!https://www.youtube.com/watch?v=udf7w7ZjnXg&feature=youtu.be

author: james_s
author_rank: Super Contributor
timestamp: May 20, 2019, 05:52:17 am
content: Quote from: T3sl4co1l on May 20, 2019, 03:57:48 amI wonder if leaks in the engine bay tend to be higher pressure, lower velocity? I've had blown exhaust manifold gaskets a few times and it makes a sharp tick-tick-tick sound vs the much deeper hotrod sound when the muffler is shot or missing.

author: Zero999
author_rank: Super Contributor
timestamp: May 20, 2019, 08:28:29 am
content: Quote from: Audioguru on May 18, 2019, 03:04:37 amI agree. I hate noisy cars an motorbikes. They should be banned.I can see the need for some noise and electric cars can be too quiet, as people don't hear them coming, but a lot of it is excessive.

author: Circlotron
author_rank: Super Contributor
timestamp: May 20, 2019, 10:23:40 am
content: A good V8 at 9000+ rpm sounds pretty cool IMHO.https://youtu.be/fbTRaDQ1tJA

author: mikerj
author_rank: Super Contributor
timestamp: May 20, 2019, 02:27:15 pm
content: Quote from: ebastler on May 18, 2019, 07:50:51 amA Ferrari F1 V12 engine sounds nothing like a model aircraft engine. I've heard people suffering from a broken exhaust on their car with a wheezy four pot engine and say "it sounded like a Ferrari". Is a significant proportion of the population unable to distinguish different sounds?Quote from: james_s on May 18, 2019, 07:10:43 amWhat a lovely noise, I could listen to that all day

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 20, 2019, 03:00:21 pm
content: Quote

author: james_s
author_rank: Super Contributor
timestamp: May 20, 2019, 05:22:36 pm
content: I also thought the race engine in the first video sounded a lot like a modelAirplane engine, high pitched whine, very short stroke, very high RPM, it's not a sound I find pleasing at all but to each their own.

author: Circlotron
author_rank: Super Contributor
timestamp: May 20, 2019, 11:59:46 pm
content: One day soon internal combustion engines will be the new vacuum tubes.

author: james_s
author_rank: Super Contributor
timestamp: May 21, 2019, 12:11:17 am
content: They'll be around for a long time on aircraft, especially turbines. You're not gonna see an electric jumbo jet without a drastic new development in energy storage tech. Liquid fuel has a very big advantage in that the craft gets lighter as you burn it off.

author: langwadt
author_rank: Super Contributor
timestamp: May 21, 2019, 12:24:33 am
content: Quote from: james_s on May 20, 2019, 05:22:36 pmI think the sound of high powered race engines is something that is perceived quite different combined with the memory hearing one in real life

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 21, 2019, 12:27:53 am
content: Quote from: langwadt on May 21, 2019, 12:24:33 amIt's the audio equivalent of cilantro I guess.

author: langwadt
author_rank: Super Contributor
timestamp: May 21, 2019, 12:30:11 am
content: Quote from: NANDBlog on May 18, 2019, 08:32:31 amF1 might not be physically painful loud as they used to be, but I refuse to believe a 12krpm 800hp V6 isn't making one hell of a racket

author: james_s
author_rank: Super Contributor
timestamp: May 21, 2019, 02:10:44 am
content: Quote from: Alex Eisenhut on May 21, 2019, 12:27:53 amSometimes I think I'm the only guy out there ambivalent to cilantro, everybody seems to either love the stuff or hate it. I could take it or leave it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 21, 2019, 02:39:00 am
content: Quote from: james_s on May 21, 2019, 12:11:17 amNo need to qualify the statement -- you justwon't. They're hard pressed to win any further gains in efficiency, as it is; even with highly cost-effective and efficient manufacture and charging (say, cheap materials and hydro power, I guess?), the fact remains that, a theoretically perfect battery (perfect in terms of what's on the Periodic Table) is, at absolute best, only justcompetitivewith fuel. (And the best pair the Periodic Table offers, are not cost-effective elements.) And indeed, as mentioned, doesn't benefit from the rocket equation (weight falls over time).You'd much more likely find proposals of CNG (or cryo NG?) aircraft, say? To even begin to be feasible, that would require the price of natural gas to go near-zero for a viable length of time. But even so, that has obvious and serious problems, roughly comparable in magnitude to the electric question I think.The real innovation I'm looking forward to: a reasonably simple, highly efficient method for transforming one or more energy sources (thermal, photo, electric..) into long-chain hydrocarbons. An ideal example would be a catalyst for a reversible hydrocarbon fuel cell. Or to put it another way: solve fossil fuels by making them carbon-neutral, so that they aren't "fossil" anymore.Tim

author: bsfeechannel
author_rank: Super Contributor
timestamp: May 21, 2019, 02:50:21 am
content: Quote from: Circlotron on May 20, 2019, 10:23:40 amIt reminded me a little bit of our old floor polisher when I was a kid. I don't know why.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 21, 2019, 03:47:35 am
content: Quote from: T3sl4co1l on May 20, 2019, 03:57:48 amMy 1999 Toyota Camry sounds like an antique "sewing machine" externally at start up.I can usually recognise Toyotas from around that year, as they all sound like that.Strangely, my Camry sounds beautifully smooth & nearly silent when cruising on the open road.My old Leyland P76 V8, with an after market twin system sounded great --- classic "tuddy, tuddy" sound when cruising the back blocks of the WA wheat belt.The kids loved it--- they would sit in the back, with the windows down, revelling in the sound, & the air rushing in.They liked to get in & out through the windows, "Dukes of Hazzard" style!When I was a kid, I particularly liked the old "sidevalve" Ford Customline exhaust sound, too.The sound that really gets my attention, however, is a big old turbocharged Dorman Diesel firing up.When this happened, it was when a power fail occurred, so there is an element of "Pavlov"s dogs" in it!The next place I worked had Detroit Diesel Standby plant, much more efficient, but for character, they never quite matched those scary old "Brit beasts"!

author: Liam
author_rank: Newbie
timestamp: May 21, 2019, 05:25:32 am
content: I do not understand the point in making this. Do you need a sound? It can be created using the program on the computer. I do not understand the purpose of which you are pursuingExplain in more detail what you want and why.

author: james_s
author_rank: Super Contributor
timestamp: May 21, 2019, 04:26:18 pm
content: Quote from: T3sl4co1l on May 21, 2019, 02:39:00 amWell there are other theoretically viable methods of producing thrust that are not internal combustion engines. Fuel cells and steam turbines come to mind. I'm not suggesting either of these are the future by any means, simply that they do not require violating the known laws of the universe. There was at one time serious exploration into the concept of nuclear powered aircraft, this could probably be accomplished using existing technology aside from the obvious safety issues.

author: David Hess
author_rank: Super Contributor
timestamp: May 22, 2019, 02:35:05 am
content: Quote from: james_s on May 21, 2019, 12:11:17 amThis is especially the case with aircraft where if batteries are used, the entire mass of the batteries has to be carried for the entire flight. Fuel only has to be carried until used.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 22, 2019, 02:35:36 am
content: Cars are pretty weak when it comes to sound and acceleration compared to this madness0-60 in just over 0.5 secondsafter 3 seconds, 240 mph

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 22, 2019, 02:39:45 am
content: Quote from: floobydust on May 18, 2019, 05:24:59 amI hate to break it, but many car manufacturers nowadays use the audio system to boost the exhaust sound. That's more flexible and makes it a lot easier to pass regulations. Some cars even allow you to set different profiles and have a differently sound of choice.

author: Mr. Scram
author_rank: Super Contributor
timestamp: May 22, 2019, 02:49:31 am
content: Quote from: Alex Eisenhut on May 22, 2019, 02:35:36 amApparently top fuel dragsters can match or beat that.

author: David Hess
author_rank: Super Contributor
timestamp: May 22, 2019, 02:51:39 am
content: Quote from: Mr. Scram on May 22, 2019, 02:39:45 amI am surprised they also did not use the active suspension to tilt the car when the engine is revved.

author: james_s
author_rank: Super Contributor
timestamp: May 22, 2019, 05:01:53 am
content: Quote from: Alex Eisenhut on May 22, 2019, 02:35:36 amI never found those sort of purpose built drag vehicles to be all that interesting though really, I mean they're completely useless for anything other than a very brief drag run. A car or boat that you can actually use is a lot more interesting.

author: Circlotron
author_rank: Super Contributor
timestamp: May 22, 2019, 05:18:12 am
content: I simply put clothes pegs and football cards on my bicycle spokes.

author: sleemanj
author_rank: Super Contributor
timestamp: May 22, 2019, 08:47:46 am
content: Not engine sound, but all this talk of sweet sounds makes me think of the Hawker Hunter Blue Note, skip to 15 seconds.https://youtu.be/6z1CZ64fyb8

author: bsfeechannel
author_rank: Super Contributor
timestamp: May 22, 2019, 07:27:18 pm
content: Quote from: Liam on May 21, 2019, 05:25:32 amIf you are referring to the OP question, it is probably relating to what you can infer from the design of something by the sound it produces.A long time ago in a far away galaxy, I worked for a lab that performed sound measurements in cars. The goal was to provide acoustic comfort for the driver and passengers.The measurements were taken in a controlled environment and objectively analyzed so that the engineers could pinpoint the exact sources of noise and try to mitigate it.It was not exactly reverse engineering, but it was a puzzle that had sound as a starting point.