simple Q about old speaker design

[canca87]

Hi all,

This is probably a really stupid question, but I opened up an old speaker to see if it was still in good condition. When I opened it I noticed over one of the woffer ports there was a cardboard circle with rubber around the edge (much like the rubber around a speaker). The cardboard moves opposite to the main woffer, much like a speaker moves. FYI there are no port on the speaker.

The question is, whats the cardboard bit for?
Can i rip it off and put a second speaker there without ruining the speakers accousitcs?
Would i need to adjust the crossover? or add a port to the speaker box?

If you want or need more info just ask, happy to give.

Cheers all

ps, sorry for asking what may seem like an obvious question to you all.

[454Casull]

That's a passive radiator. It does the same thing as a port.

If I were you I would do a little more research before trying to modify the speakers.

[wakibaki]

Put it back together exactly as it was if you can, making sure that it does not leak. If you can't do this, you have destroyed it.

Don't take speakers apart to 'see if they are in good condition' in future. You test a speaker's condition electrically and acoustically and by inspection of the front of the cone and any radiators.

WTF is a woffer?

w

[Cal Weldon]

No you can't put another speaker in there. It is set up to do the job as is. As the others have mentioned, put it back together with perhaps a little sealant to ensure a leak free box. To test if you have it right, put your fingers around the center dust cap and push the cone of the woffer (sic) inward and hold. The passive radiator should move outward as you expect and remain pretty much stationary for a second or two. If everything is perfect it will remain in place for a number of seconds before slowly relaxing back to the center point. Release the woffer and watch the passive radiator suck back into the cabinet. It should take only about a second before both are centered and stationary. Hopefully you left the other speaker alone so you can do a comparison between the two.

Now, keep your grubby little fingers off of them or as my Father used to say: No touchee!

[canca87]

fair enough. i have left the other one alone, but when i say i opened it up to see if it was any good i just mean i took the front grill off to see if the rubber seals around the cones (what are they called?) were still there.

well the seals around the cone on one of the radiators was deteriorated, is there any way to replace it? The other speaker is still good, and i see what u mean about how it moves.

Thanks

[Cal Weldon]

Glad to hear you didn't open them up.

The rubbery thing that holds the cardboard in place is called the surround. Yes you can buy new surrounds but the cardboard type radiator is relatively inexpensive so you might consider buying new ones. Always replace in pairs.