How can I amplify the sound of an electric brushless 1000 watts motor used in electric motorcycles and scooters ?

Thread Starter

Spaceheadddd

Joined Jan 19, 2022
1
Hi guys,

My company assembles electric motorcycles and mopeds. We are considering launching our own electric motorcycle line up and I noticed EV's are very silent despite the reduced noise levels this is impacting pedestrians on busy streets especially in India where majority of people don't use the footpath to walk and the traffic is outrageous in most cities. I was wondering how I could make the motor louder or just loud enough for pedestrians to know or notice the vehicle coming to them. I personally like the sound of any electric motor over an internal combusting engine as they sound futuristic in a peculiar way.

We currently are using 1,2,3,4,5 and 6 Kw electric brushless hub motors and the top speed of our bikes are limited to 50 Kmph for mopeds and 80 kmph for motorcycles with three different modes that act as gears. The motor hub is installed on the rear wheel and its powered using 60 V or 72 V lithium iron phosphate batteries that depends on the customer's preference. The ampere of the batteries varies from customer to customer as well. We are allowing customers to choose the mileage/range. The highest Amp battery we used was 60v 72 amps to give a customer 180-210 Km range. I noticed that the higher the capacity of a motor the more sound it is likely to produce however most of our customers prefer the 1 Kw or 2 Kw motor and the noise produced by the motor is minimal and hardly audible.

At first I thought of using microphones and an amplifier to increase the noise of the engine after thinking about it a lot I felt this idea was not the best one to approach as the sound of the engine is likely to be altered or the microphone might pick up other sounds from the surroundings or even get wet. I don't have any electrical engineering or a foundational physics background and I'm finding it difficult to find a solution. Please share your thoughts and Ideas about it and kindly be elaborative as it might help me understand your solution to the problem better.

Thank you Guys.
 

Yaakov

Joined Jan 27, 2019
5,488
For a variety of reasons it is much more sensible to synthesize a sound that is similar to the motor and play it from a speaker. It could be done so it is relatively directional providing the most sound in front of the vehicle which would maximize the utility of the sound (to warn people potentially in the path of it).

You could use a digital recording of the motor sound, in a loop, and change the playback speed and/or volume in proportion to the throttle position. It's probably not a very hard problem to solve for an engineer experienced in digital audio, and being in India I suspect you could find someone relatively easily who would be affordable.
 

Rich2

Joined Mar 3, 2014
241
The Volkswagen UP GTI has a similar thing on it to make it sound sportier.. I Forget what they call it now...

Googled it, it's a Soundaktor
 

Audioguru again

Joined Oct 21, 2019
4,523
All young guys here have the muffler on their car replaced with pipes so the car sounds louder than hell.
These guys do not drive electric cars because they like the stink of having the pollution controls removed from gasoline powered engines.
Even when I was young I liked my cars to have "stealth silence".

If I walk on the road then I am using the "wrong" side so I can see cars coming and jump out of the way if needed.
 

nsaspook

Joined Aug 27, 2009
9,437
For a variety of reasons it is much more sensible to synthesize a sound that is similar to the motor and play it from a speaker. It could be done so it is relatively directional providing the most sound in front of the vehicle which would maximize the utility of the sound (to warn people potentially in the path of it).

You could use a digital recording of the motor sound, in a loop, and change the playback speed and/or volume in proportion to the throttle position. It's probably not a very hard problem to solve for an engineer experienced in digital audio, and being in India I suspect you could find someone relatively easily who would be affordable.
A simple sound loop device should work.
https://www.aliexpress.com/popular/voice-record-playback-module-isd1820.html

My warning horn.
 

bloguetronica

Joined Apr 27, 2007
1,521
Use a metal sheet strip in a way that it will hit the wheel spokes. It works!

Anyway, nice to see that you are using LiFePO4 batteries instead of that junk that catches fire. They are better, although their capacity is slightly lower when compared to traditional batteries. And they don't have nasty cobalt extracted from warring countries in them.
 

atferrari

Joined Jan 6, 2004
4,574
Electric forklifts of all brands I know, are certainly very quiet machines. All are fitted with an automatic audible signal when moving backwards quite similar to the annoying non musical tone employed with trucks or low loaders.

Adding noise to noise for almost deaf people sounds a non solution.
 
Last edited:

k1ng 1337

Joined Sep 11, 2020
417
All young guys here have the muffler on their car replaced with pipes so the car sounds louder than hell.
These guys do not drive electric cars because they like the stink of having the pollution controls removed from gasoline powered engines.
Even when I was young I liked my cars to have "stealth silence".

If I walk on the road then I am using the "wrong" side so I can see cars coming and jump out of the way if needed.
You can hear my car coming from a good block away. Before I was good at stick shift I liked it quite to hide my poor skill. Now I like it loud as hell because I love the sound of engines. I'll never understand "straight piping" as you explained (bypassing the CC etc.), that's just a plain disregard for the environment which makes me mad but if someone doesn't like loud noises that's their problem (freedom of expression and noise bylaws should be respected). Generally it's the same closed minded people who think their way of life should be ours as well.. there are much worse things in the world than a loud car or "bad music".. and I certainly don't drive reckless or try to annoy people but there are many who make that their prime agenda.
 

dendad

Joined Feb 20, 2016
4,110
How about feeding one motor wire through a speaker transformer core with the primary not connected, and the secondary to a speaker?
Or, connect a speaker to a current transformer and run one motor wire through the hole?
Clip on...
current transformer.jpg

solder on the speaker...
1643599603624.png
 
Top