Do you hear a constant whine?

[GeorgeParrott]

Rather than generate hypotheses that the high frequency noise
1. doesn't exist
2. is some sinister plot to derail EVs in general
3. is a random experience of the "anti-EV" folk

I would propose that Nissan, and the rest of us who are NOT bothered by the noise, appreciate that it does exist. The spectrographic images confirm the presence of a continuing high frequency "feedback" from the Leaf's electric drive system. Based on the comparison to the Chevy Volt, this kind of "electric power feedback noise" does NOT HAVE to be present.

So, this is an appeal for the Nissan Leaf engineers to further review their design work and "tune this out" for 2012 onward. It does the development of real EVs, like the Leaf, no good at all to have design "irritations" built in that would be a turn-off to any prospective, fully hearing enabled potential buyer (not a semi-deaf one like myself).

I am quiet "OK" with using our Leaf on a regular basis, but it is not a "happy time" to watch my wife wince as she suffers this level of auditory input.

 

[rhyde83]

Yes I hear the whine, and it isn't what the others have said -- it comes through the sound system. Apparently the power electronics generate an interference picked up and amplified by the sound system. I used to install car stereos decades ago and filters for the power line were needed on many cars.

Prove it for yourself by sitting in a very quiet environment with the car either on or in accessory mode. Turn the radio on and turn the volume all the way down -- it will whine. Turn the radio off and it goes away.

It's about a 1 kHz tone and constant - doesn't vary with speed like the motor/inverter. It's very faint and many won't hear it but it's a little irritating to an audio professional like myself.

No idea how to fix it.

 

[gascant]

It does the development of real EVs, like the Leaf, no good at all to have design "irritations" built in that would be a turn-off to any prospective, fully hearing enabled potential buyer (not a semi-deaf one like myself).

Maybe they had in mind the same thing that GM did when they introduced this commercial for the EV-1:
http://www.youtube.com/watch?v=3g7cgUm7o9k
Scary!

 

[Herm]

No idea how to fix it.

Assuming the stereo is the actual source, usually a choke or filter in the power lines of the stereo (and amplifier if there is a separate one) solves the problem.. or perhaps a direct connection, with a filter, to the battery.

 

[GaslessInSeattle]

...
I would propose that Nissan, and the rest of us who are NOT bothered by the noise, appreciate that it does exist. ...

It's also possible that the noise is isolated to a few LEAFs. The test referred to was done on one vehicle, right, comparing it to one Prius and one Volt. Surely a decent sample group of each car needs to be tested for objective conclusion. It's not that I'm not bothered by it, it's that neither my wife nor I or anyone that has been in our car has heard it. have you tried driving another LEAF to see if you hear it? Have you brought this issue up with the dealer and given them a chance to see if they can adjust something? Sorry this is an issue for you, I'd be frustrated too.
g

 

[DaveEV]

It's about a 1 kHz tone and constant - doesn't vary with speed like the motor/inverter. It's very faint and many won't hear it but it's a little irritating to an audio professional like myself.

That's not the whine people are talking about - it's the very high pitched noise that varies mostly with speed - doesn't seem to vary much with power application in my car, at least.

For me, it's most noticable with the windows down some at slower speeds, especially when driving next to any concrete walls. It's very high pitched - I'd estimate it seems to go between 7-8 kHz at low speeds and 14-15 kHz at highway speeds.

I have a bit of tinnitus and am sensitive to certain types of noise at times, so I can appreciate how this whine can be quite annoying to some.

I have found that having the radio on completely drowns it out for me at normal listening levels for those of you who are bothered by it.

 

[Lanzer]

Here's another fun hearing test that you can play with to see where your range of hearing lies exactly.
http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/

I can hardly hear 15khz and I can barely notice the high pitch whine of the Leaf while I rather like all of the noises that the Leaf makes.

Hopefully music can help drown the noise, and I wonder if there's any way of playing white noise that can cancel out the high pitch whine? Maybe keeping a pair of noise canceling headphones is the way to go?

 

[daleph]

That's not the whine people are talking about - it's the very high pitched noise that varies mostly with speed - doesn't seem to vary much with power application in my car, at least.

For me, it's most noticable with the windows down some at slower speeds, especially when driving next to any concrete walls. It's very high pitched - I'd estimate it seems to go between 7-8 kHz at low speeds and 14-15 kHz at highway speeds.

I have a bit of tinnitus and am sensitive to certain types of noise at times, so I can appreciate how this whine can be quite annoying to some.

I have found that having the radio on completely drowns it out for me at normal listening levels for those of you who are bothered by it.

Have you not considered that its actually the motor itself? It does spin up to just under 10,500 RPM

 

[Herm]

Its the motor windings and the cables.. made to oscillate by the high power pulses from the inverter.

The Volt uses a similar 10k rpm motor so the inverters for both cars are similar.. the Volt is probably better sound isolated.. or the windings are better potted.

 

[evnow]

My wife has been complaining from Day 1 about the constant high pitched whine she hears when riding or driving our Leaf. With a semi-significant hearing loss, this is not something I have been able to perceive, but today, MOTOR TREND magazine arrived with a big article comparing the Leaf, Volt and current Prius.

In this article the engineering staff of MT did recordings of the sound levels in each of the cars, and they CONFIRM my wife's complaint. There is a very strong and constant high frequency "feedback" in the Leaf that is not at all similarly present in the Volt.

Any of the rest here, notice this constant high frequency "feedback" during Leaf operation?

Couple of things. That noise profile in MT is worthless. Where is the frequency on the x-axis ? Are they talking about 100Hz to 200Hz or 1KHz to 20KHz ?

Second, if your wife is in the same age group as you, she can't probably hear anything in the actual high frequency range.

Third, a lot of people have hearing loss because of high-volume in-the-ear "music" - whether it is the iPod generation or the Sony WalkMan generation. Depending on the kind of hearing impairment, some frequencies can be more annoying than others to particular individuals. I've almost never listened to high volume in-the-ear "music", so I think my hearing is good - and I don't hear any annoying high pitch noise (though I do hear the whine).

 

[thankyouOB]

i ride with the radio on and never hear it.
then, last night I was riding with the wife for the first time, and we could hear it.
For me, the radio covers it.

 

[garygid]

The pulses to the motor probably vary with speed, so they are not likely to be the source of a fixed-frequency noise.

I presume that the inverter has to take the battery voltage (that varies wildly) and convert it to a constant high voltage DC, suitable for the high-power motor-driving circuits to use. A switching regulator that would do this would only be strongly active when the motor needs power (not in Neutral), and it would work at a fixed high frequency. So, that would fit the symptoms well, I believe.

As to the writer's family going to bed with headaches ... nobody on this forum has complained of high-frequency induced headaches. So, ... a whole writer-family vs. not one of hundreds of owner-famlies ... suspicious?

So, MAYBE the writer's family got headaches from breathing the exhaust fumes from the Volt after they had parked it in the garage to listen to it alongside the LEAF? :lol:

 

[evnow]

As to the writer's family going to bed with headaches ... nobody on this forum has complained of high-frequency induced headaches. So, ... a whole writer-family vs. not one of hundreds of owner-famlies ... suspicious?

May be they all listen to particularly bad music very loud and have badly impaired hearing ;-)

 

[rainnw]

My ears are slightly ringing after driving the car...sort of the sound you hear after a high pitched screeching sound finally stops.

 

[DaveEV]

Couple of things. That noise profile in MT is worthless. Where is the frequency on the x-axis ? Are they talking about 100Hz to 200Hz or 1KHz to 20KHz ?

The X-axis is time, the Y-axis is frequency, the color is amplitude.

If you look at the LEAF plot, you'll see that there is a narrow band of sound that ramps up - holds frequency then ramps down. That correlates with vehicle speed as the test involved accelerating up to 50 mph or something, then slowing back down to a stop.

The sharp vertical lines in the plot are the car hitting bumps.

http://www.motortrend.com/roadtests/alternative/1108_2011_chevrolet_volt_vs_2011_nissan_leaf_vs_2011_toyota_prius_comparison/acceleration_noise.html

 

[Herm]

The pulses to the motor probably vary with speed, so they are not likely to be the source of a fixed-frequency noise.

The frequency of the inverter determines the rpm in AC motors such as the Volt and Leaf use, so the pitch should go up as the speed increases.. it may be detectable if you have a good ear.

The volume may decline as the rpm and frequency goes up due to the nature of human hearing.

 

[evnow]

The X-axis is time, the Y-axis is frequency, the color is amplitude.

If you look at the LEAF plot, you'll see that there is a narrow band of sound that ramps up - holds frequency then ramps down. That correlates with vehicle speed as the test involved accelerating up to 50 mph or something, then slowing back down to a stop.

The sharp vertical lines in the plot are the car hitting bumps.

Still doesn't tell me what the actual y-axis values are. I'm fairly sure if I make such a graph in college it would have been rejected ...

 

[TangoKilo]

I fly turbine aircraft and it sounds the same
You gotta love it! :mrgreen:

 

[HIOJim]

I went to the link supplied previously:

http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/

...and couldn't hear anything beyond 15khz. But I'm 57 so what did we expect, right? On a whim, I sent the link to my 16-year-old daughter and asked her to take the test. She responded that she too could hear nothing beyond 15khz as well.

I suggested that she back off on the volume of her iPod

 

[TomT]

I suspect that it is more the fact that most computer speakers have no response to speak of at those frequencies...

I went to the link supplied previously:

http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/

...and couldn't hear anything beyond 15khz. But I'm 57 so what did we expect, right? On a whim, I sent the link to my 16-year-old daughter and asked her to take the test. She responded that she too could hear nothing beyond 15khz as well.

I suggested that she back off on the volume of her iPod