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Yes for the woofers because they are in force cancelling pairs. Unfortunately for reasons of cost in the first build I have opted for modestly priced midwoofers that do not have a way to bolt to the frame on the magnet and so I will simply use metal rods between the normal mounting holes on the...

The rate of energy pumped into the cabinet is the product of the reaction force on the driver frame to the accelerations of the cone and the velocity in direction of that force by the cabinet. Broadly whatever is required to be done on the air to generate a given sound pressure level is equally...

It is an option and had I stuck with the original double curvature or decided bending ply was going to be a problem it is what I would most likely have done. It is a fairly popular method for small scale manufacture of expensive speakers using a CNC machine to cut the stacks and was how the...

If things work out the next one may well use composite panels, double curvature and be more CNC orientated. Single curvature was a compromise to ease construction and was not in the initial paper design. I did briefly consider honeycomb but I need to rout recesses for the drivers, a conical...

Bracing stiffens the cabinet and pushes the frequency higher at which resonances start to occur. It does not reduce the sound pressure level of those resonances at the listening position which I suspect is what you are expecting to happen. At high frequencies a panel needs to deflect less to be...

Pushing resonances high works if the driver creating those frequencies is elsewhere and not exciting the cabinet. The energy to excite the resonances comes from the drivers and will be just as much present at midrange and high frequencies as at bass frequencies. What is different is that it...

I don't know why you would think that. I came to the forum somewhat uncertain about bending plywood and have been given advice that has both set my mind at rest and also given me one or two things to try which, if they work, will be better than what I was initially intending to do. Good stuff...

Thanks for the input but I think we may be at cross purposes somewhere. I may not be experienced in how to do it, which is why I am posting to the forum, but I am pretty confident one can bend 3 mm plywood if it is wet and heated. I agree it will not bend cold and dry to the radius I want and...

Stiffness goes up but so does mass and, unfortunately, the resonant frequency scales only with the square root of the stiffness/mass ratio so we get an increase but not by anything like the amount the stiffness has gone up. The resonant frequencies can be predicted using Finite Element Analysis...

Sound is radiated by the drivers (wanted) and from the cabinet (not wanted). My concern is reducing the latter sufficiently to be inaudible in the presence of the former. If you have a separate enclosure for the low frequency woofer/s which is isolated from the enclosure for the midrange and...

A flue pipe perhaps but I had thought to bend a sheet of metal and heat that possibly over the internal frame for the speaker or a bit tighter depending on the degree of spring back. Thanks I hadn't considered hot and dry but if it works it should be quicker and less messy. Well worth an...

It is about 1' x 1.5' x 2.5' and is the size of a domestic loudspeaker. Thanks. That sounds exactly like what I am after. Did you use the cheap 3 mm ply with 2 thin outer layers and a thick core or the more expensive 3 mm ply with uniform thickness? Thanks again. I had seen a few of these but...

Thanks for the input but I thought I was proposing to use the same construction method as that for wooden aeroplanes: a wooden frame and a plywood skin although in my case the skin uses more layers. I would like to use 1.5mm 3 ply aero plywood but cannot afford it (unless someone knows where I...

Thanks for the suggestion but I doubt it will be stiff enough in the circumferential direction (although I am not stating this with high confidence given the wide range of glues). The cabinet is designed to work in a particular way which requires a higher than normal stiffness.

Thanks. There is a permanent internal framework that the bent plywood will be glued to but the outside will be free. What type of glue would you recommend?

Yes that is the intention. The structure has an internal framework to make it stiff and so there will be something to bend the ply around without the need to construct something separate to do the job. Had I been able to afford very thin ply things would have been straightforward but I am...

Solid wood is usually avoided with speakers because it moves too much. Although stiff in the direction of the strips I suspect such a construction would be insufficiently stiff in the circumferential direction because of the need for something soft to accommodate movement between the strips? PS...

It is the low frequency section of a prototype (quick and cheap!) loudspeaker. If the lowest frequency resonances can be pushed to frequencies above the highest frequency handled by the driver they will not get excited and the cabinet will remain quiet. Unfortunately, a near miss is a big fail...

I am fairly sure it would not be stiff enough on it's own but bonded to an inner and outer layer of something stiff it might work.

Thanks for the warning. I was tempted by the 3mm(ish) £10 sheets at the local builders merchant but eventually accepted I would have to pay more like £30+ a sheet for marine ply to get the required stiffness.