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Thread: BobL's shed fit.
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31st October 2011, 09:00 AM #136.
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31st October 2011, 10:17 AM #137
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31st October 2011, 10:38 AM #138.
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31st October 2011, 10:42 PM #139
Might I suggest a HD foam panel about 1cm thick, sized to fit each door? This might serve a dual purpose, gasket and additional sound insulation on top of the melamine.
You have a reasonably powerful DC there Bob, and I guess it's not easy to diminish the sound as much as one would want. Of course. manufacturers could probably do a lot more to ameliorate the sound from their machines, but that might eat into the profits!!
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31st October 2011, 11:29 PM #140.
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I'm pretty sure the doors are not the problem. It seems to be coming more from the side walls probably because the DC is mounted on the side walls.
I spoke to one of the acoustics guys at work and he said I definitely need to decouple the DC from the walls. I have worked out a couple of things to try and I'll be having a go at these soon.
You have a reasonably powerful DC there Bob, and I guess it's not easy to diminish the sound as much as one would want. Of course. manufacturers could probably do a lot more to ameliorate the sound from their machines, but that might eat into the profits!!
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1st November 2011, 07:39 AM #141
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1st November 2011, 08:02 AM #142.
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Yep - on reflection 'twas indeed asking for trouble.
Currently Lip "L" sits on wooden brackect "B".
My plan is to remove both L and B and reinstall the top part of the original legs from the DC stand/trolley (as shown above). The legs won't be long enough so I will have to add ~500 mm extensions to them so the legs can stand directly onto the the ground. I will also have to cut away parts of the baffle so the legs can pass thru the baffle and make sure Il cut away enough so the legs will not touch the baffles and then seal up the holes with circular pieces of foam. The legs passing thru the baffle box will slightly decrease the size of the air exit but that is already 4.2 times greater that the area of the intake so it should be OK.
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1st November 2011, 08:50 AM #143
Bob
Good plan , but as you have sufficient space in the baffle for air flow, I would suggest reducing the size of the baffle slightly so you can place the legs outside of the baffle. Having the legs inside is likely to cause turbulence, which may be a greater problem than the reduction of cross sectional area.
Regards
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1st November 2011, 10:09 AM #144GOLD MEMBER
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Not sure either - is there some way/possibility of "hanging" the unit eg on short chain from the bracket rather than a "hard" attachment as it currently is.
It may do nothing or it could help isolate vibration.
Just a thought.
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1st November 2011, 11:10 AM #145.
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I asked the acoustician at work about chains and he said the legs would be better. I have a pair of legs from an old exercise machine that look like they are big enough and will need minimal adapting.
I would suggest reducing the size of the baffle slightly so you can place the legs outside of the baffle.
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1st November 2011, 11:18 AM #146
Hi Bob,
Might be talking out of my hat, but, before you start the big job on the new legs, what about putting some isolation pads under L on top of B. By isolation pads I mean some thick softish rubber strips or blocks. Something to isolate the vibration from the walls. They are often found on compressor units and big industrial fans for the same purpose.
Maybe give it a try, it might work enough to save you a lot of work. Just a thought, if I understand the problem correctly.
Cheers
Pops
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1st November 2011, 11:13 PM #147.
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I tried that already with both soft (doubled over mouse pad) and hard rubber pads but both still conduct most of the vibration ie , I can feel the vibe in the walls. The hard rubber is no different to the DC sitting on the wooden supports. The soft rubber is a little better but with the DC weighing in around 85 kg it just crushes the soft rubber down too much. It may work better if the soft rubber is thicker but making the support legs is going to be quite an easy job.
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2nd November 2011, 12:17 AM #148
Hi Bob,
Look forward to seeing the leg job. Hope it does the trick.
Cheers
Pops
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2nd November 2011, 11:42 PM #149.
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The naked DC is 80 dB at 1 meter.
With the DC inside the enclosure it is 75 dB at one metre from the enclosure and 72 dB at 3 m but it's hard to measure because the sound is trapped in the alleyway between the back fence and the shed and the meter reading varies depending on where it's pointed. I still have not lined the rest of the enclosure with all the sound absorbing materials. Inside the shed (just on the other side of a naked fibre-cement wall) its 70 dB. Once that shed is lined I expect to get it down a bit more.
- clad the front of the doors with color bond to protect the melamine from the weather
- improved the sealing on the doorways with some synthetic rubber window gasket material and
- patched up the cracks with "Nop Mpore Gaps".
It's far from airtight but I'm quite pleased with the improvement in the sound attentuation
The result is a 5 dB reduction all round;
70 dB @ 1 m from the enclosure
67 dB @ 3 m from the enclosure, and
66 bB @ the neighbors fence line.
65 dB inside the shed.
I still haven't decoupled the DC from the housing as I wanted to get the colorbond on in case it rained which it did this evening just as I was putting the last bit of flashing on the doors.
Have also located some serious foam for lining the inside of the enclosure.
I have a week of holidays next week so I will build an new set of legs for the dc so it can stand inside the enclosure without touching the enclosure frame.
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3rd November 2011, 07:25 AM #150
By the time you have finished and achieved the external sound level you are comfortable with, you will be able to write "An Installation Manual for the Mounting and Soundproofing of an External Dust Collector".
This could prove to be a little money spinner on the side, Bob.
Woops, shut my mouth, everyone already knows the secrets!!
Seriously though, you may be leading the way in improving what is a bane to us, sound deadening of fixed installations.
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