Have your say & ask the experts

Does bunging speakers ports have any physical/mechanical effects on the driver? If air that is being created by the physical movement of the cone, cannot be dissipated as efficiently due to the port being blocked, what is now happening to this excess air?

Most drivers have a seal between the housing of the driver and the cabinet, so is it entirely safe to effectively form a sealed box enclousre by virtue of bunging?

Andy Clough:

Bunging is a perfectly normal practice for fine-tuning a speaker's bass, and shouldn't cause any problems with the cone. Some manufacturers supply foam bungs with their speakers for customers to experiment with, and I've even used an old pair of rolled-up socks for the purpose in the past with no detrimental effect!

Do socks/bungs etc need time to 'bed in'? Are matched pairs better? Should one roll them clockwise or anti-clockwise? Are lambswool better than cotton?

Andy Clough:

Bunging is a perfectly normal practice for fine-tuning a speaker's bass, and shouldn't cause any problems with the cone. Some manufacturers supply foam bungs with their speakers for customers to experiment with, and I've even used an old pair of rolled-up socks for the purpose in the past with no detrimental effect!

Thanks Andy. Im actually using bungs supplied with my Dynaudio 72SEs (I know you guys werent too crazy about them but they match my Cyrus gear perfectly!).

When the ports are not bunger, the amount of air shifted out of these is immense, and I just wondered what sort of pressures (if any) are exerted on the cone as a result.

OK, this is going to be the very simplified version.

Yes, the whole point of using bungs is the effect it has on the driver(s) in the ported enclosure.

Proper bungs use open-cell foam, so they don't block the port tube completely, but rather impede the flow of air in it.

The result is a slight stiffening-up of the movement of the driver, due to the fact the damping effect of the air in the cabinet is increased now it can't move in and out so easily behind the driver.

Blocking the port completely will of course create a sealed box, which could over-damp the drive unit and cause a drastic loss of bass.

And for all the comedy about rolling of socks, the nature of the bung used can make a big difference. So one sock loosely rolled will have less effect than two rolled tightly and thus more efficiently blocking the tube.

If you want to get really geeky about this, try buying a big catering box of old-fashioned drinking straws, and using a bundle of these to fill the port tube. It will have a more subtle damping effect than foam bungs. Or indeed socks.

Andrew Everard:

 

Andy Clough:

...I've even used an old pair of rolled-up socks for the purpose in the past with no detrimental effect!

JAXON5:

Audiophile straws! quick hide the post before someone smells the opportunity to make a packet! :-)

No, non-audiophile straws. And people already make them in packets.

Nothing old-fashioned about drinking straws per se, but I meant to draw the distinction between the original straight waxed paper/plastic ones and the ones with a concertina section in them allowing them to be angled, or other newfangled kinks.

A pedant writes: Nice try, but you're not actually directing sound from the port.

The main point of the port is not to deliver sound, but to allow the air-pressure inside the cabinet to vary