Exhaust pipes engine sound in electric car based on Arrinera Hussarya supercar - Page 1
Forum section: electronics / projects

author: eneuro
author_rank: Super Contributor
timestamp: May 31, 2015, 11:40:34 am
content: Hello,looking for hints howto implement Arrinera Hussarya Polish supercar engine sound from exhaust pipes using elctronic components- with low frequency sound I guess- to enhance electric car security, makeing it a little bit more noisy to be able to hear such electric vehicle and avoid accidents, while people will not be able notice such quiet vehicle, so need some cool engine sound musicI've found decent engine sound in this video and my plan is to use spectrum analyser and find sound harmonics, translate it to electronic music and than make some circuit, maybe with help of using real DIY custom made exhaust pipes but with speakers inside to be able output some sound similar to this, but from HPEVI'm not a musician, so will probably have to quickly learn electronic music basis and try create such engine soundsI can only reveal for the moment, that my HPEV design is based on this Peugeot EX1 concept, so such engine sounds will match its futuristic view

author: calexanian
author_rank: Super Contributor
timestamp: May 31, 2015, 05:52:44 pm
content: No no no. It needs to make the sound the Jetsons car makes. That's far more appropriate!

author: free_electron
author_rank: Super Contributor
timestamp: May 31, 2015, 06:29:08 pm
content: a three weeler ? are you serious ? the bloody thing doesn't even have a windshield...why can't you make it look like a normal car ?why do all these alternative energy vehicles have to be either butt ugly (honda insight, prius 1 , miev ) , completely impractical (like the bmw i8 where there is only enough room for 1 umbrella... )or performance/range impaired (or the leaf that can't even take me to the airport and back without requiring a6 hour charge.. put some batteries in that thing. or the mIev : should i get out and help you push it forward ...) so that they become total and utterly useless.i wantan electrical car that is form, fit and functionally the same as a 'regular' gasoline car. same range, same look , same performance , same or more storage space. That is where the money is.and as for noise. i want an EV to be totally silent. it should be law that cars, and especially those badly tuned noisepipe motorcycles , cannot produce more than a certian level of noise. bloody obnoxius harley motorcycles. put a muffler on that pipe. and tune that engine so it doesn't sit there rambling and couging at the traffic lights. it;s 2015. it is perfectly possible tomake an engine that runs smooth and with minimal noise. look at BMW and Honda motor cycles like the goldwing. they are virtually silent and produce almost no vibration.flame on.

author: janaf
author_rank: Frequent Contributor
timestamp: May 31, 2015, 06:42:09 pm
content: Electric airplane guys have gadgets that play engine sound, coupled to motor speed control. There was a 4' Black Wolf RC model flying, using one of my 10W amplifiers to produce the sound from the gas turbine engine. Sorry, can't find any links now...

author: SeanB
author_rank: Super Contributor
timestamp: May 31, 2015, 06:48:05 pm
content: Agree on the wannabe hells angels with the noisy overpriced chrome piles. They roar around, yet all they are are streetside posers.

author: mikerj
author_rank: Super Contributor
timestamp: May 31, 2015, 07:49:29 pm
content: Something a bit like theSoundRacerthen? Obviously it would need to be modified a little for an EV since it picks up engine speed from the alternator ripple in a conventional car.

author: Johndi
author_rank: Contributor
timestamp: May 31, 2015, 09:22:22 pm
content: Quote from: free_electron on May 31, 2015, 06:29:08 pmIn regards to motorcycles, loud pipes save lives, most specifically that of the rider. I'm not a rider, but I know a few, and the tales they have told me in regards to people driving around them not paying attention and almost hitting them have been quite a few.Further, as a car enthusiast, the sound that a car's exhaust makes as you're driving it contributes equally to the pleasurable driving experience. The low rumble of an engine combined with a sweet exhaust note that you can hear as well as feel is a beautiful thing

author: free_electron
author_rank: Super Contributor
timestamp: May 31, 2015, 09:39:00 pm
content: Quote from: Johndi on May 31, 2015, 09:22:22 pmLoud pipes may save lives, but using your brain would save a lot more. Here is my experience from observing lots of motorcycles. I see more than ten a day.- they overtake cars on the right ! The rule when overtaking another vehicle is you pass it on the left. Overtaking on the right is a no no. In most countries / states that is even the law. I have to see the first motorcycle that passes me on the left.- they i variably stay inbetween lanes, even if there is abig enough opening to drive in the midddle of a lane where they would be visible in my rear view mirror. As soon as traffic slows down they zip past driving on white line marking the boundary between lanes. That is sheer stupidity. I've seen em accelerate and zoom by, on the right side, of a large bus , while on their right side there is a large van or pickup truck. The guy in front of the van can not see them co ong unless he pull far enough to the left. By that time there is no more reaction time for the biker and a collision will happen.It is totally irresponsible to do this at 40 miles an hour or more.If you want to pass by stopped traffic by splitting the lanes it should be done at a speed no more than 5 to 10 miles an hour. But no, they dont even slow down.That is sheer stupidity.Note : When i see a biker coming in my rear view mirror , and i am in the far left lane (like i am most of the time as that is the carpool lane) i will swerve further to the left to give them ample room to pass me on the right. courtesy on my sde , in almost all cases replied by the 'v' sign from the biker. I have no problem with bikers, i have aproblem with bikers that do stupid things like the stuff i explained above. I also have a problem with those bikes that have no muffler , use a stump of sawn off pipe as exhaust and are so loud and deafening they wake me up in the middle of the night racing up and down the highway a mile away. Or standing still at the traffic light going bwababawwaaaawa.... Bhwaawaaaawaa . Why do they have the urge to throttle up and down while standing still ? Is it out of fear the engine will stall ? If so : that engine needs a tune up !

author: eneuro
author_rank: Super Contributor
timestamp: May 31, 2015, 09:57:23 pm
content: Quote from: free_electron on May 31, 2015, 06:29:08 pmNo worry, i didn't say my vehicle is the same, because of I do not copy paste things and of course taken into account Lee Noble recomendations for linked above Arrinera Hussarya given to its CEOWhen he joined their team this supercar first concept changed a lot and one of the things was-he told them forget for the moment cabriolet versions just due to safety issues and they have it in the plans for future versions.Here we can see, that they even completely changed rear spoiler aeorodynamic breakes and in probably final version showed from my first link is controled by special designed software with help of local university resources.http://www.topgear.com/uk/photos/arrinera-hussarya-poland-supercar-lee-noble-2012-08-07Quotei can reveal that I will have aerodynamic brakes too, but concept is taken from... B2

author: eneuro
author_rank: Super Contributor
timestamp: May 31, 2015, 10:24:53 pm
content: Quote from: mikerj on May 31, 2015, 07:49:29 pmYep, you hit exactly I was thinking about, but didn't realized it is already done, so we'll see if it could be usable but sounds greatElectric Vehicle Electronic Engine Sound Systemhttp://eveess.com/Module is described there:http://eveess.com/evsm-2/http://eveess.com/evsm-input-signals/It looks like signal from hall sensor can be taken and this module recognizes voltages above 3V as pulses, so quite easy to integrate and demo from CEBIT 2013 there:Comparision of EV with Soundracer enabled and than disabled there: SoundRacer EV V8 - EVEESS - Shelby V8 soundIn the middle of this video above we have Zero Emmision EV with engine sounds enabled at parking and it sounds like... V8 engineAfter watching a few sample sounds those F12 sounds in classic ICE car are not so bad, but... they should allow in this sounde module multiply sensed bloody classic car RPM speed sensed from alternator ripple, to be somewhere closer to F12 engine and probably forgot about itSoundRacer V12 Ferrari soundAnyway, probably custom speakers and amplifier will be needed to adjust sound loud level to external environment, while in quiet places we do not want of course disturb beaty of silence, but ensure someone walking or on a bike can hear electric vehicle because it is what we have in our brains trained in neurons unconscious mind and in stress situations if someone doesn't hear something and can't see it it doesn't exist.Quoting again from this web site linked above they wrote something like this, so I'm prety sure it is a good way to go and implement such exhaust pipes engine sound subsystem for safety reasons and I was thinking about low frequency sounds, while they are easy to sense whil emany things vibrate at those frequenciesElectric Vehicle Electronic Engine Sound Systemhttp://eveess.com/QuoteQuoteSometimes drivers have to think on the road instead of other people to avoid collisions:"... Protect unsuspecting pedestrians and the visually-impaired from accidents involving hybrid and electric vehicles ..."Yep, so no question about it, but it should be smart solution and should allow sense environment noise level to adjust output volume, so we need to find a way to sense sound outside vehicle, while inside we might want listen to music and had no idea if someone can hear us on the streat

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 31, 2015, 10:30:44 pm
content: Quote from: Johndi on May 31, 2015, 09:22:22 pmNonsense.THIS is a sweet exhaust note.Pistons whacking back and forth sound like crap.

author: KJDS
author_rank: Super Contributor
timestamp: May 31, 2015, 10:31:38 pm
content: I was nearly run over by a Tesla at the start of the month. I'd love that to make some noise.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 31, 2015, 10:37:25 pm
content: Quote from: mikerj on May 31, 2015, 07:49:29 pmFor the old geezers like me:https://youtu.be/QWtAYSv0rZU?t=316LOL

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 01, 2015, 01:10:13 am
content: Quote from: joeqsmith on May 31, 2015, 11:28:26 pmMaybe, car sounds are engineered.http://news.bbc.co.uk/2/hi/programmes/click_online/9533769.stmhttp://www.zdnet.com/article/a-roaring-success-how-acoustics-make-us-spend-more-money-on-cars/http://www.popularmechanics.com/cars/a7923/the-rise-of-the-fake-engine-roar-11291754/Which is endlessly amusing to me.

author: SL4P
author_rank: Super Contributor
timestamp: June 01, 2015, 04:11:50 am
content: The sound is harder than the smell. Requires some synthesis of the various audio waveforms in proportion to the motion and throttle/brake position, but the smell/aroma simply requires a piece of 1-1/2 inch tubing.

author: calexanian
author_rank: Super Contributor
timestamp: June 01, 2015, 04:12:13 am
content: https://youtu.be/QdWswvLPdE0This is what you need!

author: zapta
author_rank: Super Contributor
timestamp: June 01, 2015, 06:32:40 am
content: Quote from: KJDS on May 31, 2015, 10:31:38 pmJudging from some posts here, Tesla makes too much noise.

author: zapta
author_rank: Super Contributor
timestamp: June 01, 2015, 06:42:31 am
content: Quote from: eneuro on May 31, 2015, 11:40:34 amSome car manufacturers are already doing it but for in-cockpit consumption, to enhance the driving experience. Some do it electronically while others do it mechanically.http://www.caranddriver.com/features/faking-it-engine-sound-enhancement-explained-tech-dept// and this $3k optionhttps://www.cars.com/articles/2012/06/what-does-this-button-do/Anyway, that Arrinera Hussarya looks beautiful. Looking forward for Chris Harris's test drive video.

author: eneuro
author_rank: Super Contributor
timestamp: June 01, 2015, 08:20:36 am
content: Quote from: calexanian on June 01, 2015, 04:12:13 amNope, nobody will notice thisI need button like this in wifi enabled tablet for wireless EV control and both on www control page and on vehicle dashboard, while messing with software during driving might be dangerous and quick reachable buttons with nice green backlight adjustable to external lighting conditions will be fine

author: Stupid Beard
author_rank: Regular Contributor
timestamp: June 01, 2015, 08:36:43 am
content: Quote from: free_electron on May 31, 2015, 06:29:08 pmThis video illustrates nicely why 3 wheelers are an extremely good idea.

author: eneuro
author_rank: Super Contributor
timestamp: June 01, 2015, 09:04:44 am
content: Quote from: zapta on June 01, 2015, 06:42:31 amI think, in this publicationSound Generator for Vehicle Simulation Authors - VTIis decent level of knowledge needed to do spectrum analysis of real engine sound recordings and with help of FFT transorm find engine orders to be able later simulate this engine soundIt was done for realistic vehicle simulators and it makes sense and doesn't look to complicated, while i do not need simulate all vehicle related sounds like noisy gearbox or brakeing-just nice low frequency engine sound andCsoundsoftware developed at MIT was used in this paper as example implementation of sound generation.Anyway, It could be nice create own solution for this specyfic Arrinera Hussarya supercar low RPM engine sound, while no SoundRacer module for this available for the moment, but it has custom engine -I guess -manufactured for their supercar with custom hightech gearbox, so it is interesting to try simulate this specyfic engine sound and I'm not interested in other engines for the moment and gearbox changes of course not needed in EV , so it should be quite easy implement in software with hardware electronic version in mindUsing guidelines from paper linked above making some reserach and taken one channel of stereo sound from this polish supercar.100ms part of this nice low rpm engine "soundtrack" belowQuite clean sound, so probably it is time to take more samples and follow steps described above in this paper, find harmonics, approximate than make this parametric scaled to other engine speed and some noise from TRNG to make each cylinder sound more realistic and lets make improoved custom engine sound generator based on oryginal Arrinera Hussarya supercar and amplify to make confused many local ICE folks which thinks that the more exhaust pipes they have and the more noise they make the more powerfull their engine isIf their car windows will wibrate with Arrinera Hussarya waves, maybe they turn their music to lower more appropriate level

author: Fungus
author_rank: Super Contributor
timestamp: June 01, 2015, 09:20:17 am
content: Quote from: KJDS on May 31, 2015, 10:31:38 pmIf you're crossing the road using only your ears to detect cars then I say let Darwin decide.PS: Did you learn anything from the experience? I'm betting humans can adapt to crossing the road among quiet cars. It just needs all the old curmudgeons to get run over - kill two sources of noise pollution with one stone!

author: Fungus
author_rank: Super Contributor
timestamp: June 01, 2015, 09:23:21 am
content: Quote from: free_electron on May 31, 2015, 06:29:08 pmI counted four wheels.

author: miguelvp
author_rank: Super Contributor
timestamp: June 01, 2015, 09:25:17 am
content: Quote from: Stupid Beard on June 01, 2015, 08:36:43 amDon't put the single wheel on the wrong side. In the back it should be very stable (unless you are backing up)

author: eneuro
author_rank: Super Contributor
timestamp: June 01, 2015, 09:38:53 am
content: Quote from: Stupid Beard on June 01, 2015, 08:36:43 amThey made serious mistake and should rather cut... rare part of their cars, remove bloody ICE engine and put batteries as low as possible to lower down center of mass, but of course it was made to to feed mainstream ICE fans withexample of bad vehicle engineering for some funPeugeot EX1 is close to three wheeler, but... it doesn't fall from the road, because was designed to drive not for...Muppet showPEUGEOT EX1 Rekord

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 01, 2015, 09:47:40 am
content: Quote from: free_electron on May 31, 2015, 06:29:08 pmlook carefully, its still 4 wheelers not 3Quote from: free_electron on May 31, 2015, 06:29:08 pmyes he is serious.Quote from: free_electron on May 31, 2015, 06:29:08 pmit has but it got separated on the drivers skullQuote from: free_electron on May 31, 2015, 06:29:08 pmbecause normal car is boring and gives you less chance to get laid. thats how it is with this world today.Quote from: free_electron on May 31, 2015, 06:29:08 pmto muggles, they are notQuote from: free_electron on May 31, 2015, 06:29:08 pmbecause muggles dont care as long as its "stylish".Quote from: free_electron on May 31, 2015, 06:29:08 pmbut you will have less chance of getting laid.Quote from: free_electron on May 31, 2015, 06:29:08 pmbut the noise will avoid other people, other motorists, other drivers, other pedesterians from getting in your way no matter how brainfull you are.Quote from: free_electron on May 31, 2015, 06:29:08 pmit is a compromise between sound engineering and riding with style. you may call it their unique heat signature, people will know what it is from far distance.

author: KJDS
author_rank: Super Contributor
timestamp: June 01, 2015, 10:08:20 am
content: Quote from: Fungus on June 01, 2015, 09:20:17 amI was standing in a car park. I did manage to hear the Lambos, and the Ferraris, and the Porsches, just not the bloody Tesla.

author: m100
author_rank: Regular Contributor
timestamp: June 01, 2015, 11:22:27 am
content: Quote from: KJDS on June 01, 2015, 10:08:20 amNot long after their introduction I was nearly run over by a Prius on the forecourt of a Toyota dealer (I was visiting with a friend, with no intention of buying) Never heard a thing, not even tyre noise! Yes I wasn't looking for traffic but on a quiet forecourt filled with a few dozen cars with no other vehicle movements you cannot expect a tonne or more of metal to approach without any warning. They are bloody dangerous, why some noise mechanism wasn't mandated, especially for those hard of hearing, is IMHO criminal.I know Lotus (UK cars not as in Lotus 123) developed a noise supression system back in the late 80's with the option of adding specific engine sounds mainly for those inside the vehicle. It made a relatively refined straight 4 with good soundproofing in the engine bay sound like a V8.This is the noise suppression 1990 patent no idea how this could ever be patented in this form, there may be other patentshttp://worldwide.espacenet.com/publicationDetails/biblio?CC=WO&NR=9009655A1&KC=A1&FT=Dhttp://www.google.com/patents/WO1990009655A1?cl=enThis is a much later developmenthttp://www.eetimes.com/document.asp?doc_id=1324387&http://www.gizmag.com/lotus-active-noise-control/11486/

author: Fungus
author_rank: Super Contributor
timestamp: June 01, 2015, 12:57:37 pm
content: Quote from: m100 on June 01, 2015, 11:22:27 amUhuh.Quote from: m100 on June 01, 2015, 11:22:27 amI have a problem with this word 'cannot'.

author: Rerouter
author_rank: Super Contributor
timestamp: June 01, 2015, 01:20:14 pm
content: The golden rule with traffic, is don't trust just one sense, and dont expect people to respond how you would, i commonly walk through busy bus depots without any issues, mainly because i keep track of what is moving around me,don't be afraid to take a double-take at something that caught the corner of your eye, and dont rely on other drivers to notice you and respond, i mean this all the way up to lane changes, you can only really focus on one thing at a time, and people struggle there way through this limitation by switching quickly between multiple roles, e.g. one that has caught me out in the past, your half way through changing lanes, which means your focus is almost entirely on the lane next to you, what happens when the car infront of you locks up there tyres in an emergency brake,Back to the Op, you could cheat a little, record the orignal car reving up on a dynamo, pull it apart in the frequency domain and tie it into a combination of road speed and applied throttle,

author: m100
author_rank: Regular Contributor
timestamp: June 01, 2015, 01:25:49 pm
content: Fungus, believe me, with the slightest background noise from human activity and a clean road surface without any grit, one of these battery powered killing machines could even sneak up on you and mow you down before you even had a chance to react. This was a tiny dealership, I wasn't standing in the road or on a junction, or on the route to the workshops or car park, just somewhere you might possibly get one or two very low speed vehicle movements a day as cars went out or returned from road tests, you'd need a constant 360 degree field of view to avoid the incident that I experienced.

author: calexanian
author_rank: Super Contributor
timestamp: June 01, 2015, 03:57:02 pm
content: Baseball card in the spokes?

author: Johndi
author_rank: Contributor
timestamp: June 02, 2015, 03:47:28 am
content: Quote from: Alex Eisenhut on May 31, 2015, 10:30:44 pmNice. I much prefer these though

author: eneuro
author_rank: Super Contributor
timestamp: June 02, 2015, 04:05:01 pm
content: Quote from: Johndi on June 02, 2015, 03:47:28 amToday tried to spot local road "supercars" and most "powerfull" had 4 exhaust pipes, but nothing to compare with this linked Lamborghini Huracán with Sport Valvetronic Exhaust RevvingHovever in comparision, Arrinera Hussarya real supercar sounds great from first video in this post when played in small room even with crappy old Creative subbuffer... it simply maked things to vibrate like glass and some plastic and metal enclusures, etc, so this is nothing to compare with those artificial Lambordini or SoundRacer sounds, also didn't hear anything like that today during riding bike and it seams than those exhaust pipes of local ICE folks can be easy outperformed with decent amplifier and pure Arrinera Hussarya engine sound

author: zapta
author_rank: Super Contributor
timestamp: June 03, 2015, 06:40:33 am
content: Quote from: Johndi on June 02, 2015, 03:47:28 amThat Lamborghini has a beautiful instrument panel cluster, not wasting space on a large analog MPH dial.

author: eneuro
author_rank: Super Contributor
timestamp: June 06, 2015, 08:27:38 am
content: Back to main taskIdentified Arrinera Hussarya super car V8 engine sound period.It was 67 Hz sound with 8 peaks which repeats and it is interesting that one of those peaks I've used to idenify this sequence has slightly different shape-like bigger and smaller triangle hillsWhat it can be? This is some interference between those two crossed exhaust pipes or something else?Anyway, fun part begins, while I've custom software to read.WAVfiles and can do some automated postprocessing like FFTs (with help of OpenCV) moveing averages, etc.

author: Kalvin
author_rank: Super Contributor
timestamp: June 06, 2015, 09:59:42 am
content: How about this?

author: eneuro
author_rank: Super Contributor
timestamp: June 06, 2015, 10:03:12 am
content: Quote from: Kalvin on June 06, 2015, 09:59:42 am

author: Circlotron
author_rank: Super Contributor
timestamp: June 06, 2015, 02:05:07 pm
content: Quote from: Alex Eisenhut on May 31, 2015, 10:30:44 pmYou call that an exhaust note?*THIS* is an exhaust note.https://youtu.be/pwLLKLOKybIAustralia - burnout capital of the world.

author: Muxr
author_rank: Super Contributor
timestamp: June 06, 2015, 02:27:51 pm
content: Lexus LFA has the coolest sound personally. Apparently when they were designing it, Lexus brought in Yamaha sound engineers to help them make an engine and exhaust that would sound like a 90s F1 racer:

author: Muttley Snickers
author_rank: Unknown
timestamp: June 06, 2015, 02:44:50 pm
content: I had a V8 Commodore (GM) for many years, extractors, cam, quadrajet, lsd, had twins originally and silly me got talked into a big bore, lumpy as porridge it was. Saw it on the road many years after I sold it and suffered regret, I miss the sound.And off topic, to this day I never understood the whole drifting thing, if you want a vehicle to go sideways go and steal a shopping trolley.Muttley

author: Fungus
author_rank: Super Contributor
timestamp: June 06, 2015, 03:07:01 pm
content: This thread reminds me of that Audi Advert:

author: Muxr
author_rank: Super Contributor
timestamp: June 06, 2015, 03:59:39 pm
content: Quote from: joeqsmith on June 06, 2015, 03:00:15 pmhttps://www.youtube.com/watch?v=WNgQijqB_60&feature=youtu.be&t=1260

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 06, 2015, 05:53:54 pm
content: Quote from: Circlotron on June 06, 2015, 02:05:07 pm

author: eneuro
author_rank: Super Contributor
timestamp: June 06, 2015, 08:06:17 pm
content: Quote from: joeqsmith on June 06, 2015, 03:00:15 pmYep, hopefully I've found another Arrinera Hussarya video (made by another person) from the same eventThere is not too much noise in background, so quite good source of pure engine waves.I should be able automate proces of learning this sound, while I've wrote software which runs a few moving averages and now can easy detect each V8 cylinder hit, I guess, than match similar patterns and prepare data for approximation:Update: Spectrum analysis confirms 67 Hz peak base sounds waves as expected.I've already found a way to aproximate those sample engine data, but probably it will better manually extract each full engine cycle sounds, while those available from random video recordings are not recorded at perfect conditions, so some noise filtering might be needed.Anyway, it is so close to software playback using OpenAL in realtimeNow, starting thinking of hardware solutions available like some DSP procesors od dedicated MPUs to be able perform cubic spline computation with some additional processing like adding sinus waves and noise, but adjustableThinking of a few MPUs in parallel (8 for each part of identified V8 engine cycle) but howto implement in electronic hardware cubic spline ? FPGA or something else?

author: eneuro
author_rank: Super Contributor
timestamp: June 23, 2015, 11:45:12 pm
content: Quote from: eneuro on June 06, 2015, 08:06:17 pmI've found nice WAVlibsndfilelibrary, so it was easy to read extracted sample full engine cycle sounds, than do some filtering and write WAV sound file based only 1 second sample soundsWe can se above (8 sample cycles combined, but can add easy more by passing at command line WAV files) that engine was accelerating slowly or deaccelerating, so those sample engine cycle sounds are not th esame length in time, but approximation using cubic splines will allow rescale them automaticly to the same period.For the moment tried simply mix those sample slightly filtered sounds at random order and by adding some noise to output I've got decent engine sound, but it will sound strange since we have no controll of engine RPM speed in this test and it is only 1 channel (not 2 channel stereo) audio, but fun part begins since software is stable and no crushes no moreWAV: AHS sample engine sound low RPM 10s .wavCubic spline approximation now will be easy, while we have tested reading and writing CD audio quality WAV sound files at 44100 sample rateCode:$ sndfile-info ahs_test-s3-n2-10s.wavVersion : libsndfile-1.0.20========================================File : ahs_test-s3-n2-10s.wavLength : 893768RIFF : 893762 (should be 893760)WAVEfmt : 16Format : 0x1 => WAVE_FORMAT_PCMChannels : 1Sample Rate : 44100Block Align : 2Bit Width : 16Bytes/sec : 88200data : 893726 (should be 893724)End----------------------------------------Sample Rate : 44100Frames : 446862Channels : 1Format : 0x00010002Sections : 1Seekable : TRUEDuration : 00:00:10.133Signal Max : 32407 (-0.10 dB)It is time to compose great custom engine sound music

author: eneuro
author_rank: Super Contributor
timestamp: June 24, 2015, 03:44:21 pm
content: Yep, as expected after rescaling each sample period time to [0,1] and using cubic spline interpolation of filtered few samples, each ploted sample now nicely fits into unit time period range and looks similarThis means, that we can choose whatever period we want and can calculate at 44100 sample rate new CD audio quality waveforms, since sample points are cubic spline interpolated and we can obtain value at any given normalized time within 0 to 1 period, so our samples are not discrete values no more, but ech sample is function of real numbers in [0,1] domain, so no problem to get any value between pointsNow, I need read simulated engine real RPM (it can be real ICE car too) and transform (scale) to given frequency and output sound waveforms based on interpolated samples (with other postprocessing like adding some noise, maybe some other sound harmonics) and it can be done in realtime since as RPM changes another waveforms will be generated which will reflect RPM change