Thread: Noise levels in my workshop

In my opinion the Cleavue is impossibly load unless some serious sound deadening is undertaken(it works brilliantly at what it is designed for though).
I have recently set up a new workshop with the dc in the workshop and the exhaust ducted through the roof . There is a brick parapet above the roof line and the top of the china hat so the noise is buffered to some extent.

The fence line is around 8 metres from the workshop wall and after I first started it up I couldn't believe the noise and the wife was jumping up and down saying the neighbours will be banging on the door in 10 minutes. After talking with Chris Parks(thanks Chris) I installed 4 metres of 10" acoustic HVAC to the exhaust inside the workshop and now the decibel level is 60 at the fence line with an ambient level of 55. I couldn't be happier with that as it would be practically inaudible in the next door property. I don't think that length of piping is throttling the exhaust much because the dust pick up seems as good as it ever was although I don't have anything to measure it with.

The next thing to tackle is an enclosure around the cyclone because the noise inside is still 92db 3 metres from the dc.

Originally Posted by FenceFurniture

Pardon me Derek, with a quick aside....

The guy next door says his is so loud that if I put my ear up to his I could hear it!

Can this be true? Apparently the tinnitus volume can be measured Chris? So I guess it is true. I have a hearing test booked for November, and this is the first one I've had. I do have a little tinnitus, but I believe that I still hear things that others don't. We'll see how my self assessment is, I suppose. I've always been big on muffs but like Bob I had a fair amount of loud music for a good long while.

However, judging by the way the noise of the shrieks from the childcare centre behind us bothers me (BADLY!) I think my general hearing might be pretty reasonable still. The uncontrolled little horrors are fully 100m away, but.....it makes me SO MAD!!!

They measure Tinnitus in a round about way. A sound is applied to the ears via headphones and when the sound becomes so loud it masks the tinnitus that is the level. It is slightly subjective I suppose but anyone who has it knows that the only time they can't hear the Tinnitus is when background noise is louder. I would hate to be put in a very silent room for any prolonged length of time and I believe some people have committed suicide because of it.

I know this is likely to be seen as a hijack ...

Originally Posted by Chris Parks

I guess for some of us the awareness of the damage noisy environments can do is a message too late as we are now suffering the consequences of that noise. For me my Tinnitus is so loud it masks speech and makes conversation difficult in a noisy environment. I have had it tested twice and both times was told that it was the loudest they had encountered which is a prize I never wanted.

I have similar issues to Chris, Brett and Derek.
Severe tinnitus in one ear -- so "loud" that listening to speech in a noisy environment is neigh on impossible. What I've found is that the tinnitus "volume" varies based on how fatigued or stressed I am.

The good news is that through an audiologist I know I now wear a hearing aid in the affected ear. The "bug" as I call it has effectively restored hearing to my right ear so when wearing the bug I can now tolerate visiting places like bars and restaurants. My audiologist friend set up the bug to specifically mask the tinnitus, rather than the more normal settings to improve general hearing. The bad news is how expensive the bug was.

Derek

So we can compare results could you advise if your db readings were made with any “weightings” applied
ie Were they dbZ or dbA etc. It seems like the SPLnFFT app defaults to dbA weighting on my phone
thanks
Ron

Hi Ron

I used dBA, the SPLnFFT default.

Regards from Perth

Derek

Measured some sound levels in my workshop to compare with Derek's readings. Used same App as Derek on my iPhone 6S

Workshop 6.5m x 4.65m. Shop has standard 2.4m ceiling and hard surface walls.

Hammer K3 in roughly centre and Clearview in back lefthand corner. Bosch 300mm GSM 12 GDL SCMS on right hand side in centre of long wall.

Clearview 1800 has filters on the exhausts and is totally in the W/S and is not in a cupboard. Clearview runs at 60Hz using a Allen Bradley VFD. Clearview plumbed with mostly 150mm PVC and a small amount of flex

Ambient 30.3 dBA. We live on an Island and no traffic noise. All doors and windows were closed

Clearview 1800 on its own 85dBA. One blast gate open to Hammer K3

Hammer K3 ( saw blade extended about 20mm) 80.5dBA Free running and not cutting. Raising the blade made little difference. The blade was a 300mm CMT TCG 96T

Saw and Clearview together but free running not cutting 86.5dBA

Bosch GSM 12 GDL SCMS 95.5 dBA Free running

From my point of view the most surprising results was that the Clearview was only 85dBA with no noise reducing yet fitted and that the Bosch SCMS was a very loud 95.5 dBA.

Also just the VFD was 46 dBA with its fan running on cool down after the Clearview stops.

Not had a chance to measure my Ixes Plana 7 Planer Thicknesser ( Leitz Centrotec 410mm 3 blade cutter head) yet but will later in week.
Cheers
Ron

I've not got the years behind my belt like some of you, but I tend to wear my headphones (in-ear) in the workshop, I tuck the cord into my tshirt and pull them behind my neck. In winter I've usually got a beanie on, or a hat in summer to keep everything as safe as possible.

It takes away most of the noise from hammer on chisel, and if I want to turn a machine on I put the ear muffs on.

One of the problems we find in workshops is the concrete and hard surfaces reflect the sounds, I've started putting up black framed canvas to absorb the sound as much as possible, a few even have acoustic foam behind them. I have some on the walls, and the ceiling, and where I can I've got a few rubber mats on the floor.

I wouldn't even bother trying to get absolute readings that are comparable with other peoples readings. The readings with phones etc are probably not even great for relative readings using the same phone as the frequency response may not even be flat. SPL measurements need to be made with proper, calibrated sound measuring equipment that is pre-calibrated before each reading to compensate for temperature and pressure(again with a calibrated noise source). Readings with phones are likely to be all over the place. There is a reason why a proper mic and meter costs upwards of $12000 (which is cheap compared with about $35000 for the same kit a few years ago) and about $2000+ for an annual calibration.

Originally Posted by DomAU

I wouldn't even bother trying to get absolute readings that are comparable with other peoples readings. The readings with phones etc are probably not even great for relative readings using the same phone as the frequency response may not even be flat. SPL measurements need to be made with proper, calibrated sound measuring equipment that is pre-calibrated before each reading to compensate for temperature and pressure(again with a calibrated noise source). Readings with phones are likely to be all over the place. There is a reason why a proper mic and meter costs upwards of $12000 (which is cheap compared with about $35000 for the same kit a few years ago) and about $2000+ for an annual calibration.

I agree proper gear is needed for accurate measurements but some Apps/Phones are WAAAY better than others and have surprising good specs and that's why I usually recommend that these be used.
see http://asa.scitation.org/doi/full/10.1121/1.4865269

I've checked the SoundMeter App by Faber Acoustical a number of times on my mobile against a serious meter at my former workplace both on on my old iPhone 2 and now iPhone 6 and its consistently within the rated spec.

Hi Bob,

In your experience have you found apps to return different results for the same test? eg if a phone was set up in the same room, same spot and same noise will it return different readings when conducting multiple tests?

The reason why i ask is, I question the merit of having to calibrate other than to obtain the "right" result? As couldn't one use the readings from a reputable app as a reference point. As I wouldn't have thought being a few DB's on either side wouldn't have made a huge difference?

Obviously if you're collecting data to dispute a disgruntled neighbor that might require specific results, but if you're trying to just get an understanding of the noise you're creating does it really matter?

Originally Posted by tonzeyd

Hi Bob,
In your experience have you found apps to return different results for the same test? eg if a phone was set up in the same room, same spot and same noise will it return different readings when conducting multiple tests?

I have tried a number of free and one purchased (supposedly calibrated) apps and compared them them to a decent SPL Meter I borrowed from work and cheap SPL meter I have at home.
The calibrated app and the cheap sound meter agreed with the Decent SPL meter I borrowed from work within +/-2dB. But even the worst free app was only +/-5dB out. I wish I had done a more exhaustive test of these free apps but I just wanted to find something quickly that was reliable enough.

In some ways more important than the meter is the way the measurements are done.

This is why in my post on measuring SPLs from DCs I specify that we all use the same distance from the DC and the same height above the ground. The size of a shed/enclosure and surroundings in a shed/enclosure are most likely to impose a greater variance on results than the meter does. This is also why I suggest dragging the DC outside and we'll away from reflecting and absorbing surfaces to get a more reliable reading.

Absolute readings are needed if you want to have a "discussion" with your neighbour or council but I wouldn't be using measurements from an app for that sort of thing. Most folks really just want a before and after (i.e. relative) reading to see if they are making gains on sound reducing processes/material.

The reason why i ask is, I question the merit of having to calibrate other than to obtain the "right" result? As couldn't one use the readings from a reputable app as a reference point. As I wouldn't have thought being a few DB's on either side wouldn't have made a huge difference?

Reliable apps are mentioned in the thread I refer to able. The is relatively old and there may be other reliable ones available