Sound leakage through cone material and passive radiators

[Penelinfi]

Is this generally anything to worry about? We seem to make really solid cabinets but then you still have a thin piece of paper/metal/plastic that while damped, you would think lets a bit of sound back out from the enclosure.

Maybe using smaller drivers for higher frequencies reduces this effect as you can absorb said higher frequencies better, leaving only bass for larger drivers/not enough room to be delayed

Then again maybe it's not a huge issue, as people still love the sound of all sorts of speakers with big midrange and passive radiators

 

[DVDdoug]

It's similar to a port in a ported speaker.

If there are (undamped) resonances in the box that's usually a problem anyway and they can also "leak through" the woofer cone. (If you compare box dimensions to wavelength, box resonances tend to be in the midrange. (That's separate from a tuned port.)

 

[mhardy6647]

I've never worried about it per se.
I'd "worry" more about backwave sound coming out of the ports in bass reflex enclosures.

 

[Killingbeans]

Is this generally anything to worry about?

Good question. Some designs go to pretty extreme lengths to absorb the backwave, but I've never seen any tests showing how it improves fidelity.

 

[fpitas]

I'd "worry" more about backwave sound coming out of the ports

Yes, Amir has several nasty examples of midrange leakage from ports.

 

[fpitas]

If in doubt, putting the port on the back or bottom helps a lot.

 

[mhardy6647]

Yes, Amir has several nasty examples of midrange leakage from ports.

For some reason, this statement is causing me a traumatic flashback to the the tactile transducer thread...

sorry.
sorry!

I'll stop now, I promise.

 

[mhardy6647]

If in doubt, putting the port on the back or bottom helps a lot.

True but at the cost (in the case of rear porting) of potentially limiting placement options.
That said, I've got a couple of rear-ported loudspeakers here that do fine -- but I also have plenty of space behind them.

 

[olieb]

Is this generally anything to worry about?

Probably there is no simple answer.
As so often Linkwitz has studied this, but only for the case of a tube cabinet (Pluto/Lxmini).
He took care that the back wave through the cone is damped well enough.

Pluto construction

 

[fpitas]

True but at the cost (in the case of rear porting) of potentially limiting placement options.
That said, I've got a couple of rear-ported loudspeakers here that do fine -- but I also have plenty of space behind them.

I prefer bottom ported.

 

[Penelinfi]

I prefer bottom ported.

That's another thing - people have generally said you need 2-3 feet of space for rear ports, but then we have bottom ports with 1" of space. Granted they are tuned for that, but still

 

[fpitas]

That's another thing - people have generally said you need 2-3 feet of space for rear ports, but then we have bottom ports with 1" of space. Granted they are tuned for that, but still

You need about a port width, maybe 1.5 x port width with rear ports.