Thread: Sound Insulation

Excellent, thanks John.

Interesting selection of material for the impeller housing, never come across it before today. What was your reason for choosing the Sureform?

Thanks.

I chose Sureform because it was easy to mould and was a very "dead" material ... a bit like lead, which is an excellent sound-proofing material.

That "dead" (thick, reasonably dense, soft/malleable and does not bounce) quality usually indicates reasonable qualities for soundproofing.

I have just posted some notes re sound insulation and other things on my post "Clearvue installation.

Safari

Originally Posted by John Samuel

The material I used around the blower is Sureform roof flashing. There is polyester fibre packed between the Sureform and the impeller housing. I stapled the Sureform into place. However, remember it is worth only 3-4 dB in sound reduction. Were I doing it again, I probably would not bother. The Sureform is not cheap.

I may have lied. New readings taken today indicate the Sureform and poly fibre are worth about 7-8 dB. That is a fair bit of noise.

My cyclone has been running at 60 Hz since I installed it.

Today I tested it at 50 Hz ... not a comprehensive test as I was only taking a few minutes break from my desk.

At 50 Hz it still pulls small off-cuts up the riser of the tale saw blade guard ... not as fast as it does at 60 Hz ... but it still does it. This indicates that the air flow at 50 Hz is not at all shabby. (BobL, why are you and your beaut bag of instruments so far away in Perth? It would be nice to get actual data. Feel free to visit.)

There will be those applications where it really should run at 60 Hz, especially some sanding applications.

In addition, there is power consumption and noise to consider. Obviously, it draws less power at 50 Hz. Noise readings are as below:

1. 50 Hz (all gates closed) 55-56 dB. 50 Hz (table saw gate open) 59-60 dB.
2. 60 Hz (all gates closed) 64-66 dB. 60 Hz (table saw gate open) 67-69 dB.

So, it seems that for many applications the cyclone will do a perfectly good job at 50 Hz, whilst consuming less power and at nearly half the noise levels.

In an earlier post I said my sound reading with the cyclone running was (table saw gate open) 67-69 dB.

I lied ... or at least the app on my phone did. Ronboult measured it with his clever instrument on Tuesday. It was 82 dB.

In my defence, I am partially deaf. Nevertheless, this now explains why Safari's readings and mine were different. His were correct ... mine were too low.

Many cell phones have attenuators on the microphone, to cut out loud background noises when on a call. Many of the sound meter apps are not able to access the microphone's raw output, and end up with an attenuated signal, or at the very least a modified signal. I read that all Samsung phone's mike's cap at 80db, so you'll never be able to measure more than that. I haven't researched other manufacturers because at the time I just had the Samsung.

So I deleted the sound meter app, as it was less than useless - I didn't mind if it was inaccurate, I just wanted to a comparison, but the 80db limit meant that I couldn't even get that.