Simple reversible "UFO noise" killer

The question itself reads as containing an implicit accusation that the person being asked does not care about the safety of those groups.
This perception is reinforced by the quoting of 'and boom', which adds the nuance to the above implicit accusation that the asker thinks the original post treats the subject with flippant disregard.
Finally, the follow-up lines largely just read as smarmy reiteration of the above. This is effectively internet trolling 101.

Then there's this:


Altogether, it reads as someone making an accusation rather than asking a serious question. Perhaps that wasn't your intent. In such case, you still somehow managed to choose precisely the right way to word your question so as to appear as someone who has no actual interest in getting an answer.

If somehow none of this was actually your intent, then I'm perfectly willing to walk back my own smarm and treat it with the severity with which you intended it to be delivered.

 

Indeed. Removing or altering the system is very much a "do so at your own risk" kind of thing, as even if the danger itself is largely imagined, that doesn't mean you won't get sued or something for it if something does happen, if they believe it will help their case.

 

Simply piloting a 3000-pound mass of metal around is already enough to be at the risk of others, whether they can hear you or not. It's a driver's obligation to drive safely and responsibly, and I don't believe this is a controversial statement. I also simply don't believe these devices really change anything in that regard. The effectiveness of these devices is questionable and narrow at best.

They're disgustingly loud from inside the cabin, and loud enough on the outside to have caused several people to ask me if there was something wrong with my car's engine -- in a rural environment, where there are no pedestrians or bike traffic and very little road traffic.
In a bustling city street, however, all it really does is contribute to the general environmental noise. After spending a week walking around the streets of LA and SF, one of the things I took away from that trip was the fact that, in an urban environment, vehicle noise is pretty much indistinguishable. The noisemakers in the hundreds of Teslas and gen4 Prius we encountered did nothing to distinguish them from the other vehicles in the area, and I always heard the road noise way more than the distinctive annoying tonal hiss of the ones Toyota uses.

Do I deny that people get injured or killed by quiet vehicles? No, of course not. But I also simply see no evidence to believe that these noisemakers actually help in all but a small minority of circumstances, particularly when compared to other non-hybrid quiet vehicles.

To be quite frank, there are flaws in the data presented by the NHTSA -- the difference in injury/fatality rates doesn't come down to hybrids/EVs versus ICE; it comes down to quiet vehicles versus loud vehicles. This will always be the case, but the law isn't being levied at quiet vehicles; it's levied at hybrids and EVs specifically. Given how they've handled this, it's apparent that lawmakers care less about safety than they do appeasement.

That said, the NHTSA are at least considerate enough to admit that the data is skewed based upon such factors -- they openly admit that these devices will largely not prevent fatalities, as fatalities largely occur at speeds above 35MPH, and the majority of those are caused by ICE vehicles. Noisemakers are intended to prevent simple injuries at low speeds, and will have negligible impact on fatalities.

Since as it turns out, vehicles which are louder also tend to be heavier and have features like larger frontal surface area which makes them more likely to cause a fatality if you actually do strike someone -- yet the industry doesn't seem to care about that, either, and has been flocking to SUVs and large trucks and other vehicular-manslaughter-prone vehicles en masse thanks to lobbyists carving out regulatory loopholes. Frankly, I feel like much less of a threat to pedestrians and bikers in a silenced Prius than I would driving one of those.

 

All that said, it's not like I don't see any merit at all in the general concept of the noisemaker. Personally, I just think the execution is terrible and makes the system more irritating than it's worth as a result.

That's why my next project is going to be to develop an improved version of the noisemaker ECU. Either by using an envelope follower to track the volume of the sound coming out of the stock ECU, or by connecting to the CAN system and interpreting the data directly, and using that to feed into an audio player and amplifier to control the speaker directly. This way, I can use my own sounds, and find something less annoying than what the stock system uses. Whether it's an actual engine sound (a Prius making the sounds of a big diesel engine would be particularly funny), or white noise (the pitch of the stock hum is part of what makes it so annoying, and switching to white noise would eliminate this particular point of agony), or a mariachi band on steroids (I'm kidding), there are numerous ways to improve upon that nasty UFO noise. I'd also probably try adjusting the volume to a more reasonable level based on circumstances, such as using a microphone to measure environmental noise and determine the appropriate volume level automatically. Just some ideas.

It would also be nice to investigate ways of making the sound leak into the cabin much less. It would certainly make the system more bearable to use. I'm not entirely certain how to approach this one, though.

 

Perhaps it's because of my particular relationship with audio/sound as a musician and audio engineer, or just my general inclinations as someone who regularly gets songs and other bits of audio stuck in my head to frustrating degrees, but the UFO noise in my '23 prius drives me absolutely batty. Not even exaggerating; I hate it with a passion.

When I first saw a clip of it on youtube from outside the car, I thought "oh that's not too bad", and found it kind of amusing. But after finding out how loud it is inside the car, and then living with it for a month, I really wanted to just throw the speaker in the trash. Whether the pitch clashes or resonates with whatever I'm listening to, I find it incredibly distracting how it has a distinct pitch at all. I can pick out the repetition frequency of the particular sample they used, and track the 'beat' of it in my head, whether I intend to or not. Depending on where I'm driving, it can drone on, fade in and out, and generally just intrudes all over my listening space, and constantly captures my attention in ways that I'm certain they never intended. It's just so damned loud and in my face lol

On a related note, there's this one particular chime sound that the car makes for certain things, and it matches extremely closely with a sound used in a song from one of my favorite artists, from the timbre to the pitch, and it's made me start skipping that song when it plays. Maybe this is some kind of condition; I don't know, but I'm pretty sure that if I had to live with this sound for five or more years then I might end up running someone down just from being driven insane =x

 

That would require adding a mixer of some kind into the stereo system to inject the sound over what's sent to the car's stereo speakers, which is something I'm kinda wary about doing, particularly if I'm not certain that it will achieve the desired results. The sound would also have to be carefully tuned, as the sound is altered/muffled by the material it has to pass through to reach the passenger cabin, and any differences in timbre whatsoever between the original and muffled versions of the sound would become plainly audible. The speaker is also off-center, which would require different signals to be sent to the left and right channels to account for the differences in how the sound is altered for each side -- though whether I could get the cancellation signal close enough for this to matter is somewhat doubtful. It might be worth experimenting with, though.