How much can be reverse engineered from sound ?

[Circlotron]

One day soon internal combustion engines will be the new vacuum tubes.

[james_s]

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.

[langwadt]

I also thought the race engine in the first video sounded a lot like a model
Airplane 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.

I think the sound of high powered race engines is something that is perceived quite different combined with the memory hearing one in real life

[Alex Eisenhut]

I also thought the race engine in the first video sounded a lot like a model
Airplane 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.

I think the sound of high powered race engines is something that is perceived quite different combined with the memory hearing one in real life

It's the audio equivalent of cilantro I guess.

[langwadt]

I must be missing something...What is so beautiful in this sound?  To me it sounds as a boring gigantic mosquito 

Yes, 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.

F1 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

[james_s]

It's the audio equivalent of cilantro I guess.

Sometimes 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.

[T3sl4co1l]

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.

No need to qualify the statement -- you just won'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 just competitive with 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

[bsfeechannel]

A good V8 at 9000+ rpm sounds pretty cool IMHO.

https://youtu.be/fbTRaDQ1tJA

It reminded me a little bit of our old floor polisher when I was a kid. I don't know why.

[vk6zgo]

If you want to understand just how much the exhaust system does, 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 was extremely conservative - 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)

Had 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

My 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"!

[Liam]

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 pursuing Explain in more detail what you want and why.

[james_s]

No need to qualify the statement -- you just won'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 just competitive with 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).

Well 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.

[David Hess]

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.

This 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.

[Alex Eisenhut]

Cars are pretty weak when it comes to sound and acceleration compared to this madness



0-60 in just over 0.5 seconds

after 3 seconds, 240 mph

[Mr. Scram]

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.

I 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.

[Mr. Scram]

Cars are pretty weak when it comes to sound and acceleration compared to this madness



0-60 in just over 0.5 seconds

after 3 seconds, 240 mph

Apparently top fuel dragsters can match or beat that.

[David Hess]

I 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.

I am surprised they also did not use the active suspension to tilt the car when the engine is revved.

[james_s]

Cars are pretty weak when it comes to sound and acceleration compared to this madness

0-60 in just over 0.5 seconds

after 3 seconds, 240 mph

I 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.

[Circlotron]

I simply put clothes pegs and football cards on my bicycle spokes.

[sleemanj]

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

[bsfeechannel]

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 pursuing Explain in more detail what you want and why.

If 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.