CXS-18 motor noise

[derekcohen]

My CXS 18 has a high-pitch whine, which I gather is common to this drill. But why? I have two other Festool drills, a C12 and a PDC 18/4, and they are relatively quiet in use.

Is this noise normal? Just put up with it? It does take the shine off a good product.

Regards from Perth

Derek

 

[Cheese]

My CXS 18 has a high-pitch whine, which I gather is common to this drill. But why? I have two other Festool drills, a C12 and a PDC 18/4, and they are relatively quiet in use.

Is this noise normal? Just put up with it? It does take the shine off a good product.

Regards from Perth

Derek

FWIW Derek, I assume that's the same or a very similar sound that folks complain that the CXS 12 emits. On the CXS 12 the noise is in a very narrow band and because the trigger control on Festool drills is so linear and accurate, I find it easy to work around the band if I wish to. However, as I become more used to the sound I just live with it.  [smile]

Here's the "noise zone" of my CXS 12.

[attachimg=1]

 

[six-point socket II]

Sadly something you will have to live with, Derek. At least with the current generation/ batch of motors. And it is not just Festool.

I don’t particularly like the sound/ frequency range as well. I live with it on my bread & butter do-it-all drill-drivers, but I’am happy to run the older Festool drill-drivers when I don’t want to hear that ‘high pitched screaming’.

Kind regards,
Oliver

 

[Jim_in_PA]

I've been under the impression that the "change in noise" in the newer tools is because of the brushless motor. Perhaps I'm mistaken...

 

[six-point socket II]

Everything “EC-TEC” is and has been brushless, so no, it’s not because of “going brushless”.

Kind regards,
Oliver

 

[Jim_in_PA]

Everything “EC-TEC” is and has been brushless, so no, it’s not because of “going brushless”.

Kind regards,
Oliver

The CSX18 is the only brushless Festool product I own, so I have nothing to compare to. I only mentioned it because I've read multiple discussions where that was noted.

 

[Cheese]

I just checked the DWC 18 screw gun for noise levels...it's quiet and it rotates from 0-4500 RPM, so well within some of the speed range of the CXS 12.  [tongue] 

Playing with the new CXS 12 & the old CXS 10.8, and judging strictly with my ears, the CXS 12 quiets down around 1200 RPM which is max RPM on the CXS 10.8 and then has an additional 400 RPM left. I'm thinking the annoying noise band of the CXS 12 is from about 900 to 1200 RPM. That would be easy enough to check with a strobe.  [smile]

Digging a little deeper, the Euro versions of the Festool owner manuals publish sound levels while the US versions do not, probably a European requirement.

CXS 10.8
Sound pressure level 65dB(A)
Sound power level 76dB(A)

CXS 12
Sound pressure level 75dB(A)
Sound power level 86dB(A)

CXS 18
Sound pressure level 72dB(A)
Sound power level 83dB(A)

DWC 18
Sound pressure level 72dB(A)
Sound power level 83dB(A)

That 10dB difference between the old and the new is huge.

 

[squall_line]

Digging a little deeper, the Euro versions of the Festool owner manuals publish sound levels while the US versions do not, probably a European requirement.

Was there a distance published in the manual for those levels?

I only ask because it bothers me every time I look at my Makita leaf blower and see the "60 dB (at 50 feet)" sticker.  I don't care how loud it is at 50 feet (well, okay, I guess a little, for my neighbors), but from a safety perspective, it matters quite a bit more how loud it is at 24-30 inches, which is all the further away the motor is from my head.

 

[Cheese]

Was there a distance published in the manual for those levels?

Yes & no... [big grin]

It does refer to an EN standard, but then you'd have to dig into that standard to get the real answer. This is for the CXS 12.

[attachimg=1]

 

[squall_line]

After digging (emphasis added by me):

"This value of Q has been determined, during experimental investigations, to be applicable to hand- held power tools. The resulting A-weighted emission sound pressure level at the workstation is equivalent to the value of the surface sound pressure level at a distance of 0,7 m from the power tool. This distance has been chosen to give satisfactory reproducibility of results, and to permit comparison of the acoustic performance of different hand-held power tools, which do not, in general, have uniquely defined work stations."

There's also a formula to determine the SPL at a distance in a free field if needed.

So it looks like the answer is 0.7 meters, which is about 27.55 inches, which seems to be pretty close to the middle of my theoretical "24-30 inches from my head" statement earlier.

Neat!

 

[Cheese]

So it looks like the answer is 0.7 meters, which is about 27.55 inches, which seems to be pretty close to the middle of my theoretical "24-30 inches from my head" statement earlier.

Neat!

So that puts the drill at arms length from your ears...that's pretty reasonable.  [smile]  However, I can see the 75dB(A) being an issue if you have your head inside a cabinet and you're screwing in hinge cups.  [tongue]

 

[Birdhunter]

Years of shooting without ear protection and flying loud airplanes makes this discussion moot for me. In the old days no one even heard of ear protection.

 

[surfjungle]

Everything “EC-TEC” is and has been brushless, so no, it’s not because of “going brushless”.

Kind regards,
Oliver

I have a Fein 12 volt battery drill that's great and has been going for around 7 years. It is brushless and has a 4 speed gearbox. It is a little on the loud and whiney side. After buying the new Festool 12v CXS and TXS and comparing them to the Fein it's also loud and at times, terribly whiney. It's not bad enough to return but I do think it is unreasonable.

I also have the latest Festool 18 volt TPC at the time of writing this and while it is brushless, it's not whiney at all, presumably because it is a larger motor.

In my personal opinion, I believe it's because the Festool brushless motor in the CXS and TXS is smaller and perhaps a type that's newer compared with my Fein despite the voltages being the same.

Given I use other power tools alongside the drills so I am fine wearing hearing protection though it is somewhat unexpected. That said, my industrial Starmix vacuum is noticeably less loud than my Dyson house vacuum which makes me laugh.

 

[woodferret]

Everything “EC-TEC” is and has been brushless, so no, it’s not because of “going brushless”.

Kind regards,
Oliver

acoustic resonance (electromagnetic & structural).https://www.researchgate.net/figure/Switching-frequency-effects-on-motor-noise_fig4_245040327

Sometimes it's tied to load, hence why we're seeing it not being as obnoxious on the CXS12/18 when in actual use vs no-load air squeal.  Sometimes, it's just there as part of the switching behavior of the motor itself, which seems to be amplified at certain RPMs.

There are chip set drivers (ie TI's MCF8316A) for this sort of stuff, but probably not worth it in terms of cost/power loss/complexity for a hand tool.  They're usually reserved for home appliances.
https://www.ti.com/lit/an/slla567/slla567.pdf?ts=1720225256769

Product paper added for the EE nerds.

 

[Crazyraceguy]

I'm basically in the same situation as [member=15289]Birdhunter[/member] for different reasons. After all these years of abuse, it's not really the volume of the sound that annoys me, it's the pitch. Some of these newer brushless motors fall into that, but not all. I have a few, both corded and cordless, none of them bother me.
The most obvious corded is the TS60. While it does sound different from the brushed TS55, it's not bad, either in pitch or volume.
The biggest cordless I have is a Makita SCMS. This thing is likely to be the closest to my face as anything with a motor would be, since the stand is so high. It is not bothersome at all.
None of the Makita drills/drivers make bad noises either, but the brushless ones are the sub-compact version, so I don't know about the big ones.
The thing that most people don't like about impact drivers is the hammer mechanism anyway. It's funny how different the various brands sound in this respect too.
I'm holding on to my older CXS, for two reasons. First is because I really like it. The size, weight, and functionality are perfect for my use.
Second, is the battery platform. I prefer to keep that to a minimum. The CXS is the only battery I have, beyond the Makita LXT.
If I was already in the 18v Festool, things might be different. As a shop-only guy, not having to be mobile, I'm sticking with corded for most things. That and being tethered to a CT anyway.