The high-pitched whine during acceleration...

[gg_got_a_tesla]

Heard the same whine yesterday (initially blamed on traction control) in the non-perf Silver car in Palo Alto as my host, Nick, punched it in a straight line. Matt, our co-pilot, confirmed the frequency bit below and that they are working on changing it.

Thought I'll put together posts from the Get Amped threads about this for discussion here:

Here's the video Francis posted earlier in the thread. Start at 7:35, this is where I'm making the right-hand turn. I started to make the turn and then stepped it to the floor. Somewhere around 20-25 I heard that muted tone - I'm guessing that same "whine" you heard. So I don't think it was breaking loose in the turn, but rather when I really romped on it. I could feel I broke them loose.

http://www.youtube.com/watch?v=mVyhjJcQhG8

I heard that same high pitch tone in the MSP I drove every time I punched it straightline, too. I did several "regen down to 30 mph, punch it up to 60 mph" runs along the highway and heard that sound each time at max motor exertion, so I didn't think it was related to the traction control. Seemed more related to inverter/current delivery.

Then again, I suppose it's possible the car started detecting slip during hard straightline acceleration as well. That's a lot of torque to put down in two wheels. Some lightweight big block cars like the Corvette Z06 have no problem breaking traction in a straight line at speed after a downshift. I'd be impressed to learn the Model S at 4600 lbs can break traction under acceleration at 30mph!

From your explanation - this is the motor controller changing the switching frequency. The controller is more efficient at lower frequencies but also louder. It probably works on a higher switching frequency during during "normal driving" (within the continuous rated motor-controller power/current) for silent operation. When you floor it and the looses (heat) increase, the controller changes the frequency in order to increase efficiency. You will hear that as a whine from the rear end of the car.

At the Palo Alto event today, we were told that there is a connector through which very high current passes under heavy acceleration. It's AC, and the particular frequency causes the connector to physically vibrate, which is audible in the car. Apparently, they are considering modifying the frequency so that the connector will not whine audibly.

 

[AnOutsider]

As mentioned, I rather liked the sci-fi-esque whine and, while I may not end up missing it hardcore, it was welcome.

 

[gg_got_a_tesla]

As mentioned, I rather liked the sci-fi-esque whine and, while I may not end up missing it hardcore, it was welcome.

AO, not sure if you heard what we might be talking about here. It's not the 'regular' whine of the motor when driving; at higher speeds, when still accelerating, a second distinctive 'hollow sound' (don't know how else to describe it), distinct from the regular whine, could be heard. Wasn't nice to hear really; felt like something was going to come off somewhere!

 

[AnOutsider]

AO, not sure if you heard what we might be talking about here. It's not the 'regular' whine of the motor when driving; at higher speeds, when still accelerating, a second distinctive 'hollow sound' (don't know how else to describe it), distinct from the regular whine, could be heard. Wasn't nice to hear really; felt like something was going to come off somewhere!

Oh, then my bad. I was talking about the nice scifi-sounding whine

 

[doug]

you can hear it in my video at the 4:08 mark

http://www.youtube.com/watch?list=U...=J6pgJ590-Fs&feature=player_detailpage#t=248s

 

[FlasherZ]

To me it sounded like a muted warning tone - it wasn't variable with acceleration - it was fixed frequency and quiet. Sounded like it came from either beneath the 17" panel or beneath my seat. For me, it happened when I felt the traction control kick in, so I was wondering whether that was the cause.

 

[gg_got_a_tesla]

you can hear it in my video at the 4:08 mark

http://www.youtube.com/watch?list=U...=J6pgJ590-Fs&feature=player_detailpage#t=248s

That's the same Matt, the co-pilot that we rode with.

As can be heard on the video, the sound was prominent and noticeable.

 

[TEG]

I hadn't noticed that in E's car in Fremont, but everyone in the Palo Alto car heard something and wondered about it.
We had a theory that it might be the air suspension switching to lower ride height at a certain speed, but that could be wrong.
It seemed to happen consistently when doing quick 0-60 acceleration runs, but never when just 'cruising'.
Maybe, as mentioned, it is related to traction control?
It was defiantly coming from the back of the vehicle down by the power-train. Also it was brief and not super loud, just noticeable as an "unusual noise."
It sounded to me like it built up in frequency then suddenly would be done... "zzzssshoooweeeep".
It sounded more mechanical than electrical to me, but I could be wrong. It almost sounded like a little "servo motor" or pump came on to adjust something.

Reminded me a bit of some of the noises you hear in a jet plane when they are adjusting flaps...

 

[doug]

I was in the back seat and to me it sounded like it was coming from behind.

 

[MikeK]

Our co-pilot in Palo Alto said they call it the "deflating balloon sound", which totally fit the next time Erik floored it. I was sitting in the back, and it was very definitely coming from the rear of the car.

 

[gg_got_a_tesla]

TEG, yes, I didn't hear it either while driving a non-perf car in Fremont but, everyone in the cabin heard it in a non-perf car in Palo Alto. It did sound like it was coming from the rear.

 

[CroDriver]

you can hear it in my video at the 4:08 mark

http://www.youtube.com/watch?list=U...=J6pgJ590-Fs&feature=player_detailpage#t=248s

We had a very similar noise coming from a high-current contractor under hard acceleration. It was a one-time problem with a contactor probably messed-up during production. If this is noticeable in only one car, it could be the same issue.

However, the vibrating connector can also be the cause, we see "dancing cables" all the time during high-current bench-tests.

 

[brianman]

I still can't hear it, in either video. Perhaps an audiophile on the forum can isolate it and raise the volume.

 

[TEG]

Volume raised

 

[brianman]

All I hear is tire rumble. I don't hear a high-pitch other than the engine. Maybe there's some frequencies that I don't pick up these days.

Thanks for trying though, TEG.

 

[TEG]

Oh well, I hear "whirrrrrrrrrrrfff". Yes, a bit like a balloon letting out air through a kazoo... :redface:

 

[strider]

I heard it in the video but did not hear it on my drive yesterday (Black/Pano/Perf) in PA. That was a weird sound. Doug, which car were you in?

 

[smorgasbord]

I heard it in the video but did not hear it on my drive yesterday (Black/Pano/Perf) in PA. That was a weird sound. Doug, which car were you in?

I'm not Doug, but I drove the same car you did and we-all heard the noise very clearly and repeatedly.

Maybe you weren't putting the pedal onto the floor?

 

[TEG]

Related:

Yet another test drive report (Palo Alto, 7/15)

3. The battery makes an odd whine sound after flooring it. The rep said that they were trying to tune that out. It’s not very loud.

 

[Vegi]

To me it sounded like a muted warning tone - it wasn't variable with acceleration - it was fixed frequency and quiet. Sounded like it came from either beneath the 17" panel or beneath my seat. For me, it happened when I felt the traction control kick in, so I was wondering whether that was the cause.

I heard "both". I heard the tone that FlasherZ mention from the front dash (near the screen) and the noise from the back of the car. The tone from the front definitely seemed to be related to the traction control and the sound from the back related to hard acceleration. I heard the whine from the back several times when I accelerated hard but only heard the tone from the front when I felt the traction control really kick in.