Thread: Using available 'things' for soundproofing Impeller and motor

Some general principles.

You want to avoid air gaps so unless the fire wood is regular in shape even if the wall is 40 cm thick it will not block much noise. Likewise with wine bottle.
Foam mattress will help absorb some frequencies but you will need something dense and moderately thick (or really dense and a bit thinner) to help reflect the sound back into the box.

Other things that can be used are
Cardboard (as a foam substitute)
Bricks
Plasterboard/gyprock is quite effective and cheap and moderately dense.

My chamber consist of
Trimdeck outer weatherproofing (leftovers from the shed build)
25 mm of foil covered fibreglass insulation squished into a 13 mm gap (stuff left over from the shed build)
32 mm thick melamine covered chipboard, (I got this from a skip at my brother's workplace
16 mm chip board from an old machinery packing case
75 mm mattress from roadside rubbish collection

Bobl,
thanks for that. I was wondering about the firewood and glass having air spaces and not being solid so I am glad not to go down a path that would not be very useful. I'll see how bad it is but will keep my eyes out for thrown out foam and mattresses, etc
cheers
Mick

Hi Mick,
An old friend blew all his shavings into his wall with a 4in. hole at the top.
Place was like death inside, really shut the noise down completely.

A few things I can think of.....polystyrene vege boxes, old shag pile carpet, egg cartons stacked together, old thick blankets, as has been mentioned all these "soft" things still need to be backed up with something hard/dense, masonite, ply, cement sheet, lead.





Pete

Originally Posted by pjt

A few things I can think of.....polystyrene vege boxes, old shag pile carpet, egg cartons stacked together, old thick blankets, as has been mentioned all these "soft" things still need to be backed up with something hard/dense, masonite, ply, cement sheet, lead.





Pete

Peter,

thanks. I'll keep on the lookout for throw out mattresses but may need to buy something for the hard/dense part

cheers

Mick

Originally Posted by issatree

Hi Mick,
An old friend blew all his shavings into his wall with a 4in. hole at the top.
Place was like death inside, really shut the noise down completely.

issatree,
I have read the above a couple of times but am not sure what it means
cheers
Mick

Speaking of "sound deadened rooms" I once had to do some work at the 2GB building in Sydney (The mob I was working for at the time built the building) My job took me into one of the broadcasting booths. It is a very weird sensation just entering the room. The acoustics were absolutely non existent, no background noise what so ever you are even aware of your own heartbeat. Using a hammer to tap some thing...no bounce of sound at all and when you have a conversation you become aware of just how much we hear, is resonating sound.
It was so long ago (1974)(and I was wet behind the ears) I can't remember what the insulating material was, sorry. I wish I could remember because I want to quiet down my dusty/cyclone set up. A muffler really only vented the exhausting air outside

Originally Posted by chambezio

Speaking of "sound deadened rooms" I once had to do some work at the 2GB building in Sydney (The mob I was working for at the time built the building) My job took me into one of the broadcasting booths. It is a very weird sensation just entering the room. The acoustics were absolutely non existent, no background noise what so ever you are even aware of your own heartbeat. Using a hammer to tap some thing...no bounce of sound at all and when you have a conversation you become aware of just how much we hear, is resonating sound.
It was so long ago (1974)(and I was wet behind the ears) I can't remember what the insulating material was, sorry. I wish I could remember because I want to quiet down my dusty/cyclone set up. A muffler really only vented the exhausting air outside

Standard materials for booth are double brick walls and acoustic foam under floors, and lining the walls and ceiling and triple glazed windows. If you want to get really serious a metre thick concrete or lead lined acoustic insulation does a pretty good job. Even non-lead lined acoustic foam is very expensive. We used it in the ceiling for a noisy lab at work and it cost around $100 m^2.

For any DC enclosure there comes a point where further insulation is wasted because the chamber needs a vent.

Originally Posted by mick59wests

issatree,
I have read the above a couple of times but am not sure what it means
cheers
Mick

I think what Issatree is refering to is the shavings from jointer/thicknessor can be used as an insulating material, there does need to be a space that will contain the shavings i.e not self supporting, similliar idea to shredded newspaper used to fill wall cavities and such.





Pete

Hi Mick,
Yes, I was a bit short on facts.
This Older Chap had a single car garage, & an old one to boot.
He bought some 2nd. hand Masonite, Covered the 4 walls, put 4in. holes up the top, just under the board to nail the outside tin too. Covered the roof as well with Polystyrene.
Had a longish pipe going into the hole from a Lurem Combination Machine. So when ever he was Sawing, Planing or using the Thicknesser, everything went into the walls.
He wood change it around every so often.
He could have Machines going, & as you walked up to his shed, you wood have thought he was having a Cuppa, as only when you got to the little side door did you notice the noise, that was almost nothing.
Dead as a door nail inside that Shed.

I will look further afield but based on Bunnos prices, chipboard is about half the price of melamine. Is anyone aware of the effectiveness of the different building materials?
cheers
Mick

Originally Posted by mick59wests

I will look further afield but based on Bunnos prices, chipboard is about half the price of melamine. Is anyone aware of the effectiveness of the different building materials?
cheers
Mick

I used the 32 mm melamine purely as a something with a bit of density compared to say foam, but chipboard should be as effective as melamine.
If you want cheap and effective then gyprock will be the go as it's denser than chipboard.

Originally Posted by BobL

I used the 32 mm melamine purely as a something with a bit of density compared to say foam, but chipboard should be as effective as melamine.
If you want cheap and effective then gyprock will be the go as it's denser than chipboard.

BobL,
thanks once again - it is cheaper as well
cheers
Mick

Gentlemen, there are three factors to consider in all acoustic problems, transmission, reflection and absorbtion.

The current acoustic establishment ( the acoustic consultants) seem to be blinkered on transmission and isolation and to cost of considering reflection and absorbtion.

You do not need to completely seal a space to reduce noise...in fact, in a great many situations it is impractical to completely seal....so don't even try.

enclosing somthing on 3 sides with highly absorbent material can realy knock the guts out of its noise output.

If you build a highly reflective box that almost sealed but not quite....the noise will keep bouncing round till it comes out the holes.

I have seen a few..brick bunker acoustic crontrolls ( pool pump sheds and compressor sheds) that where completely ineffective, because of this error.

If you enclose as best as possible and then introduce as much absorbtion as is practical, you can reduce noise dramaticaly.

Our workshops, homes and other hbuildings are soo full of highly reflectice surfaces, intorducing any absorbtion can be most effective.

one example....my aluminium drop saw was mounted againts a hard solid reflecive wall.....I fitted some acoustic panels on the wall and reduced the noise levels considerably.

I did a treatment job for a music school...they had built this string of tuition rooms..selaed em up good and tried hard to reduce the transmission in the walls...but all the walls and the cieleing where still hard and reflective... they still had problems.....I fitted corner absorbers in 2 corners of each room.....it substantially reduced the noise level in the rooms and droped the leaking sound considerably

I have been involved in building a few..low cost music practice rooms and similar things.

MDF & chip board are both heavy, dense and dead materials and reduce transmission considerably...plywood still effective but less so...thicker heavier better.

I've got all the figures on gyprock... B#@!y poor in comparison with MDF.

16mm MDF realy takes some getting thru.


lining the inside of the blower shed with MDF or chip...you can do a hell of a lot worse....stuff the cavity with something.....so much the better...carpet the inside walls...all good

don't get obsessed with gaps or completely enclosing...but you do need to introduce considerable absorption.

the matress while perhaps a fire hazard...will introcduce considerable absorbtion.....it will be like knocking a 2 meter square acoustic black hole in the wall.....I've used matresses and they work well....but they are bulky and prone to vermin infestation.

Blankets...hell when I was a kid, that is what we used to shut up the church halls we where running concerts in....we'd hang the blankets over the roof trusses or spreader bars.
In this situation...don't bother.

The boxes of fire wood, or better end stacked fire wood will act as an absorber and an acoustic torturous path....all the gaps and voids certainly wont seal sound....but they will break it up and absorb it...not much sound gets thru a close stacked pile of firewood.....the irregular and gappy end surface will be pretty well non reflective at all but the lowest frequencies.

Egg cartons and egg trays, are practically useless.....they may break up a hard bright surface, but they have no effect at anything like a low frequency.....I did have some fugures on egg cartins at one time.....trust me don't bother.

carpet..the thicker and heavier the better.....knocks out high frequency reflectiuon pretty well and reduces transmission right across the band.


As far as insulation in the walls....before fibreglass and plastic foams became cheap and easily available many things where used for both acoustic and thermal insulation....sheeps wool, cotton and the like...but of interest to wood workers..buzzer chips.....the light curls and fleks off planers & thicknessers....virtually unknown these days but very effective.

I did a job for a butcher in a very old butchery....his cold rooms where all silky oak,and the walls where filled with buzzer chips.....he had never encountered a cool room the kept its temperature like it...the acoustic performance would be simiar.

as for the bottles....not much use...while in medievel times they buit big open pots into walls half filled with ash...they where only marginally effective and the openings where way bigger than bottles.

as for the fan.....start with the source...reducing transmission right at the fan housing will produce results.....make sure you isolate the fan and its motor on vibration mounts..use some sort of soft hose to couple to the ducts and treat the actual blower housing with somthing like car body deadning pads....even gluing carpet to it will shut it up.

cheers