Push-Push or Push-Pull

[planet10]

Originally posted by Bigun
The rods will be in tension and could have a piano-wire oscillation in which the box would be a wonderful sound board.

That is what the afore-mentioned heat-shrink is intended to combat.

dave

[MJL21193]

Originally posted by Bigun
Right now I have only a couple of little clamps which aren't long enough to get across the side of the cube. There are two sides of the box gluing in the basement, two bags of cement on top and my tool box hanging off some string on one corner to close a gap and some rubber mats on the floor in case the string breaks.

Yes, I've been there too. The funkier it looks, the better it clamps - bucket o' screws, paint cans, 18" woofer... it's all good.

[AKN]

Hi,

When I mentioned rods earlier I did think of solid rods thick enouth to be threaded in the ends. Thus allowing use of ordinary machine screws securing the driver units.

Thoughts of this idea?

[Bigun]

MJL - looks great, I think we're going to need a dedicated thread for everyone to show off their jury-rigged gluing operations !

4fun/Dave - I've gone with the no.10 threaded rod and I'll put something on them to damp vibrations. I don't have heat-shrink but something else will be found. I don't fancy starting with plain rod and cutting my own threads - don't own the tools and it's not worth it for this one project.

Moondog - definitely need some bracing in the corners between sides. I just happen to have some very nice quality thin-ply (packaging from an Italian football table). Thin means quick and easy to shape and drill holes in. Thin doesn't mean it's not strong. The floor joists in my house are made from engineered wooden I-beams with very thin verticals. The trick is that they are deep - a beam's stiffness depends very much upon it's depth. So I've cut up the thin ply and glued it all over the inside of the box, edge on, to create a very stiff structure with little penalty in weight or volume. A bang on the side makes a nice satisfying 'thunk'. Not sure if this photo explains it any better...

[Moondog55]

Photo explains every thing very well, what damping if any are you using inside the cabinet??

That tapped rod idea did sound interesting, easy to do if you have a lathe

[Bigun]

Originally posted by Moondog55
what damping if any are you using inside the cabinet??

I have some man-made poly-bat left over from the Moon-Onkens that I bought locally. It's white, fairly stiff, doesn't shed fibres and is in a large sheet about 3/4" thick. Since I have no other use for it I planned to cut it up and use it in the sub. I don't really need much in the way of 'stuffing' to increase apparent box volume so it's more in the way of damping.

I'm still thinking about the BASH500 plate amp. It has some internal heat sinks so I have decided not to put it into it's own box within the enclosure. This allows some air movement around those heatsinks. But, it's a Class-D amp and they produce EMI. So I'm now thinking about adding some conducting mesh and foil. I have some local expertise where I work and will seek some advice on that today.

[Bigun]

end of this discussion about driver quantity and time to show results

continued at: Altair Sub (2x TRIO8's)