Something stirs in the Undergrowth

Dedicated to those large boxes at one end of the room
vinylnvalves
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Re: Something stirs in the Undergrowth

Post by vinylnvalves » Sun Nov 15, 2020 10:48 am

I think the oversized box and just fill it with stuff is the easiest. When I dismantled some speakers a few years back.. I remembered where I put all my university text books. I think Bruce Edgar recommended the water bottles. Plastic bags of rice etc is just as good. I just want to see the results of this Midbass horn this decade :wink:

JamesD
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Re: Something stirs in the Undergrowth

Post by JamesD » Sun Nov 15, 2020 11:16 am

Rice is a good idea - I used whatever I had been using for blind baking such as rice, dried beans or seeds - sunflower seeds were popular, sugar bags or small clay granules all in bags... not sure of the compressibility factors of the different materials though... What sort of pressure differences are to be expected?

I had not come across the idea of water bottles before but I guess it is an incompressible fluid...it will compress but not by very much...

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IslandPink
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Re: Something stirs in the Undergrowth

Post by IslandPink » Sun Nov 15, 2020 1:18 pm

Thanks Ant - good point. I should get some loading from a cardboard box. I'm ahead of you on the water bottles, I did that already with the folded horn. Yes, maybe it was Bruce who suggested that ?
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )

izzy wizzy
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Re: Something stirs in the Undergrowth

Post by izzy wizzy » Wed Nov 18, 2020 12:20 pm

IslandPink wrote:
Sun Oct 25, 2020 10:57 am
Well , after some more purchasing of bits ( filler, dremel cutting discs etc ) I finally got the mouth section tidy enough to fit to the rest. Yesterday was sound check #2. I must say this thing sort-of dominates the room -

The sound is good but not amazing. It has gained some extension into the bass, with the mouth added. It's a bit hard to evaluate without filtering, as there's a lot more out of band energy ( upper end ) than expected. You have to sort of tune that out when listening and concentrate on things like lower percussion and bass guitars. The mouth section is not rigid enough ( as expected ) it needs another layer of fibreglass, I'll do that inside - plus a brace from top to bottom.
The other thing I need to do its make a back volume for the driver. I think this bigger, longer horn will benefit from this more than ones I've done in the past. This could be a faff, I'm just thinking about how to do it - it'll be cylindrical, using the phase plug surround as the starting point.
I just used fibreglass for the first time on a gully betwixt house and garage so outside. None of the stuff is on me yet I stink of resin fumes. Can't imagine the smell if you did that inside. Will it permeate soft furnishings or does it die away after a while?

Anyway, hope this gains you the sound you're after.

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Ali Tait
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Re: Something stirs in the Undergrowth

Post by Ali Tait » Wed Nov 18, 2020 1:39 pm

It'll die away.

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Ray P
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Re: Something stirs in the Undergrowth

Post by Ray P » Wed Nov 18, 2020 4:32 pm

izzy wizzy wrote:
Wed Nov 18, 2020 12:20 pm
I just used fibreglass for the first time on a gully betwixt house and garage so outside. None of the stuff is on me yet I stink of resin fumes. Can't imagine the smell if you did that inside. Will it permeate soft furnishings or does it die away after a while?

Anyway, hope this gains you the sound you're after.
That's why I use epoxy resin whenever it's viable for the job.

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IslandPink
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Re: Something stirs in the Undergrowth

Post by IslandPink » Wed Nov 18, 2020 4:50 pm

Yes it was pretty bad in the house, especially when I did about 4 sessions in two days. I had the front sash window open a few inches and the back door likewise, some air flowing through - but I tended to escape and go out for a walk when it was at its worst. It does dissipate but can take a few days to completely go. The thing you've got to avoid is underestimating the catalyst - then it'll smell for weeks !
Epoxy would be nice but is twice the price of polyester resin.
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )

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