DIY passive cone / drone cone

[Freedom666]

When making a new enclosure always thought taking one box side wood panel as a passive moving "cone" putting it on a smooth pipe of silicon or the like.

But never found a material which can be easily fixed and has the desired properties.

Anyone has an idea?

 

[Freedom666]

For making a big diy passive radiator I used surrounds and cut out wood from one panel.

One easy way to do it.

 

[Freedom666]

Just using the wood from one panel and glueing the surround directly on the box and the cut out wood making a diy passive driver.

But even more elegant it would be to use one complete panel fitting it on something flexible

 

[jjasniew]

Rubber stall mat? Comes in various thicknesses at Tractor Supply and the like. I once thought of making an entire enclosure out of it, but too flimsy for that, the thick stuff too expensive.

Now if you could machine it to a shape; thick in the center, gradually going thinner toward the edges, that might be something. I dont have the tools for that. I'd pick a thinner sheet and add mass to the center.

Unsure how "pistonic" the motion would be, without a means to square up the degree of freedom, like the spider does for a woofer -

 

[Freedom666]

Is it that?

 

[jjasniew]

Yes, it comes in various thicknesses; the really thick stuff that would make a horse happy - or a weight lifting room - might be too much. The stuff I saw sitting in the sun outside rippled like water when shook, guessing 5/8"...

 

[Freedom666]

The passive radiator should move easily with high excursion capability and not much losses and the linear the better.

So some kind of smooth silicone would do, should be formed like this?

Both sides wood panels

 

[Freedom666]

The silicone should be ventilated to the outside not compressing the air inside.

Towards the box inside it should be airtight

 

[Freedom666]

For more stability four layers of zig zags side by side but smooth silicone or rubber?

 

[Freedom666]

Could also be like this like Olsons full roll surround

 

[stv]

Consider the weigth of the wooden board (sagging) and the possibility of it to wobble (non pistonic movement)!
Maybe door seals could be used?

 

[Freedom666]

Or using just one straight type endless surround of stiffer type or a variation of a full roll using existing surrounds

 

[Freedom666]

Sometimes you need weight if the box is small.

Maybe like this using existing surround material of straight type.

 

[Freedom666]

This Windows insulation could be maybe used

Could be used from both sides gluing the rubber together at the flat side.

Wood should be prepared to take the ends

But it must be ventilated, maybe automatically where the ends are meeting in the squares

 

[jjasniew]

I bought someone's cube sub at a thrift store; 3 of six sides were 'cone'; one driver and two passive radiators. They look like this;

Notice how their construction forces a pistonic movement via two suspensions with a distance between. I think you'll need this, for a DIY idea to work -

 

[Freedom666]

@jjasniew
Pistonic movement is better.

Passive radiators are sold which are not built like this.

Are they sounding less good?

It can be that long stroke drivers need PRs which are more linear in travel.

If you have a main driver not being long stroke and big passive radiators the tumbling motion is less.

In post 2 the tumbling motion can be less with this construction.

 

[Freedom666]

@jjasniew

The PR in Post 15:

The yellow spider can add losses to the movement. Maybe this was intended.

Ah, no! It's ventilated at the side! Good!

The theory goes for minimal losses