Simple reversible "UFO noise" killer

From all of the responses from various members about the NOISE factor in the Prius I doubt if any of them have actually been in the cars to hear them firsthand. The fact that the Prius has this one speaker in the front of the car for both noise making while going forward as well as in reverse is just plain stupid. Going in reverse is twice as loud as forward. Why??? Because they are too cheap to put a speaker in the back of the car and one in the front. for their noise making. ALL of these cars should have these speakers in the proper places and for the proper noises.

 

um....

No Comment.

 

You could run over and kill cats sitting/sleeping under your car and not to mention hit people.

 

i don't mind having an option to toggle between the 'ufo' sound and an 'ice cream truck.'

 

Hhmmm. Mine doesn't make any sound like described

 

I did some research as I have a friend that would prefer an in between solution if possible. While my friend does find the noise annoying, they wanted to try and reduce it a bit rather than kill it entirely. Enter the "L Pad" circuit. This will let us reduce the volume of the speaker while still presenting a similar 8 ohm load to the amplifier. Here's a calculator that let's you work out resistance values based on how much attenuation you desire. For reference, -6dB "sounds" roughly about half as loud to most people.

For example, an 8 ohm speaker attenuated 6dB will require a 4 ohm series resistor and an 8 ohm parallel resistor. A package of 3.9 ohm resistors is close enough to make this combination fairly easily. HINT - 2 of the 3.9 ohm resistors in series makes 7.8 ohms which is close enough to 8 ohms for our purposes.

I'll report back on how my friend likes the results.

 

Trying the silent life for a bit. Since I like to overcomplicate things I made a box for my resistor. Here's the files so you can make your own. Printables

 

@planetarian, thanks for sharing this. After I read this thread, I could not unhear the ufo sound lol It is loud and I remember doing a similar mod to my F150 hybrid as well.

I ordered the Toyota 90980-11162 harness and 8.2 ohm / 2W resistors to tackle this project (amazon didn't have 3W readily available). 90980-11162 is the male that plugs into speaker and it turns out we need the female that plugs into engine side wire. Instead of chasing that part number and waiting, I just cut the tip off the factory harness and soldered the resistor in and removed the speaker altogether from the car.

FYI - I had to disconnect battery terminal for the error on dash to go away as it stayed on even after soldering in the resistor.

No more UFO sound and pedestrians will never hear me coming (we have had a Tesla for 3 years and never have we felt the need to have a UFO sound to increase safety).