Thread: Clear Vue installation

Originally Posted by John Samuel

Safari,

Android phones can download a free app that is a sound meter. My guess is that other phones have a similar app.

Is this the device you used for your sound level measurements?
The problem with these is the phone mikes are not capable of picking up the low frequencies or low intensities correctly.
However, they should be fine for comparative purposes ie this is louder / softer than this.

Doug and BobL,

My Android app maxes out at 100 dB. Given that my first reading was 97 dB, it must be regarded as a bit suspect.

However, I read an article about a bloke took his android app to work and compared it with the instrument the OH&S folk use and got very good agreement through the entire range. Nevertheless, BobL's point is well taken. I use it for a comparative rather than an absolute basis because I have no way of calibrating the app.

One test I did do was a distance test. As I understand matters sound pressure follows the inverse proportional (1/r) rule, rather than the inverse square law, so if the instrument is OK, from a given source of sound the dB reading should halve as one doubles the distance between the source and the instrument. My app does this, so at least as a comparative measure, it looks OK. (Be careful with this test. If sound is enclosed, like in a shed, it can bounce around and bugger up your readings. Ideally, the test should be done where the sound is free to radiate in all directions.)

My app seems to work best with louder noises (like woodworking machines), but only because at low levels of noise, the ambient or background noise contributes too much to the signal. I was trying to test it with a digital alarm clock at one stage, but the birds in the trees made the signal the instrument was trying to read too variable.

Originally Posted by John Samuel

Doug and BobL,

My Android app maxes out at 100 dB. Given that my first reading was 97 dB, it must be regarded as a bit suspect.

My iPhone App maxes out at 110 db but I doubt it reads that correctly.

However, I read an article about a bloke took his android app to work and compared it with the instrument the OH&S folk use and got very good agreement through the entire range.

Is that the "volume" or "frequency" range - the problem with most sound meters is measuring low frequencies and I doubt whether most machinery rumble (i.e. low frequencies) would be picked up by the small microphones in mobile phones.

Originally Posted by BobL

I doubt whether most machinery rumble (i.e. low frequencies) would be picked up by the small microphones in mobile phones.

I strongly suspect that ignoring low frequency rumbles is designed into phone microphones, because if you didn't you'd need to filter them out. Most phones are pretty good at leaving out steady background noise.

After reading this thread, I downloaded something called Sound Meter by Appsdev onto my Android phone, and according to that my dog growls at 81db. It didn't register her bark, as it was too short in duration. I'll do some fiddling when I get a chance and see what it says about my bagpipes - that should give me an idea of where it maxes out.

A mate came over today with his Iphone and decibel app. We ran the cyclone for a couple of short periods ( approx 3-4 mins ) and recorded 98db with the cyclone as pictured in my previous post. This surprised me because I was expecting the sort of reduction that John S experienced so clearly I have a lot more work to do to make it acceptable to me and the neighbours.
I have searched the forum re sound deadening and apparently rockwool is a reasonable product or do you recommend some other product?

On one of the tests the motor slowed down then sped up a couple of times, hopefully not a sign of trouble to come.

Sorry Warmtone, I forgot to ring the firm today but will do it tomorrow

My wife said that if all else fails we can we can block off the end to the dust bin and make it into a unique fish tank!!

Hi Warmtone. I just rang the firm and they said Reece will sell it so I suppose any of the plumbing supply places would too so you could do some price comparisons.

Safari

Originally Posted by safari

A mate came over today with his Iphone and decibel app. We ran the cyclone for a couple of short periods ( approx 3-4 mins ) and recorded 98db with the cyclone as pictured in my previous post.

Is this outside or inside? and at what distance? You should specify a distance for every reading. Typical distances are 1m and 3m and maybe at the boundary with your neighbour.
I don't believe the high dB end of the iphone App reads right. My iPhone reads over 100 dB when I whistle at it from about 1/2 m and I am a crap whistler.

This surprised me because I was expecting the sort of reduction that John S experienced so clearly I have a lot more work to do to make it acceptable to me and the neighbours. I have searched the forum re sound deadening and apparently rockwool is a reasonable product or do you recommend some other product?

I can't tell from you photos but it looks to me like you have a galv roof (with motor very close to the roof) and wooden walls? Is cyclone/impeller free standing or is it mounted onto the wall? ? If so, the shed structure may be vibrating - Can you feel the structure vibrating? Being shed roof will be reflecting sound back down very efficiently which will

Where do you intend to put the rockwool? as it will do very little for shed vibe Making the unit totally free standing will make a difference as this is what I had to do with mine. Lining the roof with the rock wool or carpet will reduce sound being reflected down from the roof.

Thanks for the reply BobL. Yes my stand is connected to the wall with screws and rubber door stops because it seemed a bit top heavy because of the narrow base. Perhaps I could sit it on a rubber base and dynabolt it to the floor.
The shed is a work in progress and I have yet to line the ceiling. I have just been out to the shed after reading your post and detached the frame from the wall and there was a noticeable reduction.

After reading some more post on sound deadening this morning if I line the stand both sides with MDF and have a layer of rubber floor mats and Bradford Sound Screen between I will achieve a good drop in DB's

The sound reading was taken from about 1 metre - We are new to this so am floundering a bit!

Originally Posted by safari

Thanks for the reply BobL. Yes my stand is connected to the wall with screws and rubber door stops because it seemed a bit top heavy because of the narrow base. Perhaps I could sit it on a rubber base and dynabolt it to the floor. The shed is a work in progress and I have yet to line the ceiling. I have just been out to the shed after reading your post and detached the frame from the wall and there was a noticeable reduction.

I wouldn't bother with the dyna bolts or rubber mats. I would just disconnect it from it's rigid fixing to the the wall and just loose tie it to the wall at the top with a couple of short ropes so it cannot tip over. The further up you tie it the smaller the rope can be. If you are worried then just widen the base a bit.

After reading some more post on sound deadening this morning if I line the stand both sides with MDF and have a layer of rubber floor mats and Bradford Sound Screen between I will achieve a good drop in DB's

My understanding is that (unless something is not right) the noise should primarily come from the exhaust ad that is all that needs shielding. Shielding the Cyclone is not supposed to do much.

Originally Posted by safari

On one of the tests the motor slowed down then sped up a couple of times, hopefully not a sign of trouble to come.

I had exactly the same issue. In my case it was caused by the sparky who left the motor wired for star (415V) rather than delta (240V). It buggered a VFD. Worth checking ...

You might try this. Take a sound reading 1.5M from the cyclone. Then back out of your shed taking readings at 3 and 6M. If the readings about halve at 3M compared to 1.5M, and halve again at 6M, the sound you have is coming directly from your cyclone. However, if they are significantly more than half at 3M, and don't halve again at 6M, it is likely you have sound bouncing around your shed. The fix for each is different.

i don't get too much bouncing noise, I suspect because I have 12 feet ceilings and plasterboard insulated with glasswool overhead.

Bob,

In answer to your question about volume and frequency, I think the answer is volume, if by volume you mean the sound pressure level, which is measured in dB. Like our ears a microphone measures sound pressure, or the change in air pressure caused by sound waves, but unlike our ears microphones can be tuned to register different frequencies. My guess is that my instrument is weighted to measure the frequency range ears hear, dB (A), but it may not be weighted at all. Not sure, and in my case, I don't think it matters much because as you indicated I am more interested in comparative levels (before and after) than I am in absolute values.

As you know, when trying to soundproof something it is important to understand frequency, because materials that will absorb a lot of high frequency sound can fail badly at absorbing low frequency sound. It seems that when I compare the noise of my unsuppressed cyclone with what I have now that whilst it is much quieter there is a higher proportion of low frequency sound after the suppression. Passive sound suppression works better at higher frequencies. Low frequency noise (the rumbling from a cyclone is a good example) is a bitch to contain passively. So, if I want to further suppress the sound, I likely need to think about materials that will do a decent job of absorbing low frequency sound.

If I put my ear to the wall, I can just hear a low rumble, which disappears as soon as I lift my ear from the wall. It's there, I just can't hear it through air. Fortunately, the cyclone is now quieter than my shop vac and most of my other machines. In my case, there seems little point in pursuing sound suppression further.

Originally Posted by safari

A mate came over today with his Iphone and decibel app. We ran the cyclone for a couple of short periods ( approx 3-4 mins ) and recorded 98db with the cyclone as pictured in my previous post.

It might be a good idea to get the inlet duct work up soon. BobL might know whether this is likely to impact on noise levels. I'm not sure.

Originally Posted by John Samuel

You might try this. Take a sound reading 1.5M from the cyclone. Then back out of your shed taking readings at 3 and 6M. If the readings about halve at 3M compared to 1.5M, and halve again at 6M, the sound you have is coming directly from your cyclone. However, if they are significantly more than half at 3M, and don't halve again at 6M, it is likely you have sound bouncing around your shed. The fix for each is different.

I lied. Sound does bounce around in my shed ... just checked it. As I backed away from the cyclone, sound dropped, but slowly. Then I stood at the door to the shed and took a reading, at double that distance from the cyclone (now in the open) the reading halved, as predicted by theory. So, it seems that even in a shed with high ceilings, a fair bit of noise bounces around such that sound levels do not halve as the distance to the source is doubled.

From a range of 3M the sound level is 64dB. At the entrance to the shed (8M) it is still about 58dB. At 16M it drops to about 32dB, but one must account for the breeze in the trees and my attempts to capture readings between bird calls. It's close enough to half between 8 and 16 M for me. But inside the shed it never falls below 58 dB, regardless of the range.

Originally Posted by John Samuel

From a range of 3M the sound level is 64dB. At the entrance to the shed (8M) it is still about 58dB. At 16M it drops to about 32dB, but one must account for the breeze in the trees and my attempts to capture readings between bird calls. It's close enough to half between 8 and 16 M for me. But inside the shed it never falls below 58 dB, regardless of the range.

On the decibel meter on my phone it never reads below 40 and never goes over 90. Still, not completely useless, just very very limited.