Forums

Synthesizing Engine Sounds

Started by Tim Wescott July 30, 2013
I'm toying with a notion which is probably never going to come to 
fruition, but has me thinking hard (and having fun in the thinking).

Part of it is to realistically synthesize an engine sound based on the 
speed of a rotating shaft.  Think about a playing card in the spokes 
brought to the digital era.

I'm pretty sure that much of an engine's exhaust note is basically an 
impulse or a "whoosh" of escaping gas that's filtered through the 
acoustics of an exhaust system.  So in theory I should be able to 
replicate an engine's note by recording the firing of just one cylinder, 
then repeating this one sound as necessary, with all due overlapping as 
the speed increases.

Does anyone happen to know if this results in a realistic sound?

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 7/30/2013 1:17 PM, Tim Wescott wrote:
> I'm toying with a notion which is probably never going to come to > fruition, but has me thinking hard (and having fun in the thinking).
There are several patents about engine diagnostics based on processing sound that engine makes. Vladimir Vassilevsky DSP and Mixed Signal Designs www.abvolt.com
On Tue, 30 Jul 2013 13:17:51 -0500, Tim Wescott
<tim@seemywebsite.really> wrote:

>I'm toying with a notion which is probably never going to come to >fruition, but has me thinking hard (and having fun in the thinking). > >Part of it is to realistically synthesize an engine sound based on the >speed of a rotating shaft. Think about a playing card in the spokes >brought to the digital era. > >I'm pretty sure that much of an engine's exhaust note is basically an >impulse or a "whoosh" of escaping gas that's filtered through the >acoustics of an exhaust system. So in theory I should be able to >replicate an engine's note by recording the firing of just one cylinder, >then repeating this one sound as necessary, with all due overlapping as >the speed increases. > >Does anyone happen to know if this results in a realistic sound?
There are several products on the market and even high-end OEM's (e.g., BMW) that syntehtically produce engine sounds through the car audio system rather than listening to the actual sound of the engine. Some hybrid/electric vehicles do this for fun as well as for driver feedback. BMW (and others) allow you to select a gnarlier sound than your car actually makes, for Walter Mitty types or to impress passengers or whatever. It isn't trivial to make it sound good, and the dynamics change a lot depending on how much load is actually on the engine, rpm, ambient conditions, etc., etc. In many cases a lot of engine noise comes from the intake rather than the exhaust, and how they combine contributes to the resulting sound. Getting 80% of the way there for a fun application may not be nearly as difficult, though, depending on what you want to do.
>-- > >Tim Wescott >Wescott Design Services >http://www.wescottdesign.com >
Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
Den tirsdag den 30. juli 2013 20.17.51 UTC+2 skrev Tim Wescott:
> I'm toying with a notion which is probably never going to come to > > fruition, but has me thinking hard (and having fun in the thinking). > > > > Part of it is to realistically synthesize an engine sound based on the > > speed of a rotating shaft. Think about a playing card in the spokes > > brought to the digital era. > > > > I'm pretty sure that much of an engine's exhaust note is basically an > > impulse or a "whoosh" of escaping gas that's filtered through the > > acoustics of an exhaust system. So in theory I should be able to > > replicate an engine's note by recording the firing of just one cylinder, > > then repeating this one sound as necessary, with all due overlapping as > > the speed increases. > > > > Does anyone happen to know if this results in a realistic sound? >
https://www.youtube.com/watch?v=MtrSNFjkGdU ;) -Lasse
On Tue, 30 Jul 2013 13:38:31 -0700, langwadt wrote:

> Den tirsdag den 30. juli 2013 20.17.51 UTC+2 skrev Tim Wescott: >> I'm toying with a notion which is probably never going to come to >> >> fruition, but has me thinking hard (and having fun in the thinking). >> >> >> >> Part of it is to realistically synthesize an engine sound based on the >> >> speed of a rotating shaft. Think about a playing card in the spokes >> >> brought to the digital era. >> >> >> >> I'm pretty sure that much of an engine's exhaust note is basically an >> >> impulse or a "whoosh" of escaping gas that's filtered through the >> >> acoustics of an exhaust system. So in theory I should be able to >> >> replicate an engine's note by recording the firing of just one >> cylinder, >> >> then repeating this one sound as necessary, with all due overlapping as >> >> the speed increases. >> >> >> >> Does anyone happen to know if this results in a realistic sound? >> >> > https://www.youtube.com/watch?v=MtrSNFjkGdU > > ;) > > -Lasse
Well, it's not exactly what I had in mind, but it's cute in its way. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Tim Wescott <tim@seemywebsite.really> wrote:

> I'm toying with a notion which is probably never going to come to > fruition, but has me thinking hard (and having fun in the thinking).
> Part of it is to realistically synthesize an engine sound based on the > speed of a rotating shaft. Think about a playing card in the spokes > brought to the digital era.
Reminds me, in the director's commentary of the last Bourne movie, there was a comment about the sounds of the motorcycle and car. I don't remember exactly, but they modified the sound from that recorded directly to make it sounds "right". Otherwise, it might be that the sounds of one cylinder changes depending on engine load. Idle is not just the same sounds but slower, for example. -- glen
On Tue, 30 Jul 2013 19:46:11 +0000, Eric Jacobsen wrote:

> On Tue, 30 Jul 2013 13:17:51 -0500, Tim Wescott > <tim@seemywebsite.really> wrote: > >>I'm toying with a notion which is probably never going to come to >>fruition, but has me thinking hard (and having fun in the thinking). >> >>Part of it is to realistically synthesize an engine sound based on the >>speed of a rotating shaft. Think about a playing card in the spokes >>brought to the digital era. >> >>I'm pretty sure that much of an engine's exhaust note is basically an >>impulse or a "whoosh" of escaping gas that's filtered through the >>acoustics of an exhaust system. So in theory I should be able to >>replicate an engine's note by recording the firing of just one cylinder, >>then repeating this one sound as necessary, with all due overlapping as >>the speed increases. >> >>Does anyone happen to know if this results in a realistic sound? > > There are several products on the market and even high-end OEM's (e.g., > BMW) that syntehtically produce engine sounds through the car audio > system rather than listening to the actual sound of the engine. Some > hybrid/electric vehicles do this for fun as well as for driver feedback. > BMW (and others) allow you to select a gnarlier sound than your car > actually makes, for Walter Mitty types or to impress passengers or > whatever. > > It isn't trivial to make it sound good, and the dynamics change a lot > depending on how much load is actually on the engine, rpm, ambient > conditions, etc., etc. In many cases a lot of engine noise comes from > the intake rather than the exhaust, and how they combine contributes to > the resulting sound. > > Getting 80% of the way there for a fun application may not be nearly as > difficult, though, depending on what you want to do.
It's for making an electric-powered airplane sound like it has a heavy- metal radial engine. Since I'd be trying to use a propeller as a speaker, getting 80% of the way there would be a feat in itself. Going from the starter gear whine, to the "pop-pop-pop" of idle would be enough -- once the prop actually starts going good and fast the propeller noise would overwhelm any engine sounds you could get from the motor. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
On 7/30/13 3:10 PM, Tim Wescott wrote:
> > It's for making an electric-powered airplane sound like it has a heavy- > metal radial engine. Since I'd be trying to use a propeller as a > speaker, getting 80% of the way there would be a feat in itself. > > Going from the starter gear whine, to the "pop-pop-pop" of idle would be > enough -- once the prop actually starts going good and fast the propeller > noise would overwhelm any engine sounds you could get from the motor.
do you want it to sound like a big airplane or a model airplane (with those stinky little internal combustion engines)? is some little sound system going up in the plane? is there a ROM in this? how much room in the ROM? maybe you want to simply play back a sampled waveform of the engine sound you want. -- r b-j rbj@audioimagination.com "Imagination is more important than knowledge."
On Tue, 30 Jul 2013 13:38:31 -0700 (PDT), langwadt@fonz.dk wrote:

>Den tirsdag den 30. juli 2013 20.17.51 UTC+2 skrev Tim Wescott: >> I'm toying with a notion which is probably never going to come to >> >> fruition, but has me thinking hard (and having fun in the thinking). >> >> >> >> Part of it is to realistically synthesize an engine sound based on the >> >> speed of a rotating shaft. Think about a playing card in the spokes >> >> brought to the digital era. >> >> >> >> I'm pretty sure that much of an engine's exhaust note is basically an >> >> impulse or a "whoosh" of escaping gas that's filtered through the >> >> acoustics of an exhaust system. So in theory I should be able to >> >> replicate an engine's note by recording the firing of just one cylinder, >> >> then repeating this one sound as necessary, with all due overlapping as >> >> the speed increases. >> >> >> >> Does anyone happen to know if this results in a realistic sound? >> > >https://www.youtube.com/watch?v=MtrSNFjkGdU > > ;) > >-Lasse
lulz...coming from you I knew what that was before I clicked on it. ;) Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
On Tue, 30 Jul 2013 15:32:19 -0700, robert bristow-johnson wrote:

> On 7/30/13 3:10 PM, Tim Wescott wrote: >> >> It's for making an electric-powered airplane sound like it has a heavy- >> metal radial engine. Since I'd be trying to use a propeller as a >> speaker, getting 80% of the way there would be a feat in itself. >> >> Going from the starter gear whine, to the "pop-pop-pop" of idle would >> be enough -- once the prop actually starts going good and fast the >> propeller noise would overwhelm any engine sounds you could get from >> the motor. > > do you want it to sound like a big airplane or a model airplane (with > those stinky little internal combustion engines)?
No. I want it to sound like a Pratt & Whitney.
> is some little sound system going up in the plane? is there a ROM in > this? how much room in the ROM? maybe you want to simply play back a > sampled waveform of the engine sound you want.
Sound systems are for weenies. I want the motor and propeller (and possibly the fuselage) to be the transducer. There is ROM, but I want the engine sound to match the propeller speed. See, I don't want much :). -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com