Re-foaming my Advents--What to do next???

[Circuits & Concepts 320]

I started re-foaming my Advent speakers over the Holiday break with assistance of my daughter, Emily.  I enlisted her assistance, as she is listens to them most regularly.

 

We got the baskets and cones cleaned off.  The next step in the directions says REMOVE THE DUST CAPS.  I understand that aligning the voice coil is very important.

 

My question for Kevin (or anyone else who wants to chime in) is whether the voice coil can be aligned without hacking into the dust cap.

 

Thanks in advance for your help!

 

Les

 

[madmike46 398]

When I re-foamed my Advance A+ speakers I got new center caps with my surrounds.  The caps that came with my surrounds were and exact match to the originals.  With the cap removed you can use shims between the voice coil and the center magnet pole.  Once the surrounds are dry ( I left them for 24 hours) then take the shims out and the glue the cap with the same glue as you used for the surrounds.  I used a razor knife and carefully cut the cap as close to the original glue line.

 

It can be done with out removing the cap, you just have to be more careful with alignment.  Move the cone in and out and listen for any rubbing of the voice coil and the pole piece.  the spyder should keep them in relative alignment.

 

Hope this helps out.

 

Mike

[mbskeam 1,975]

you can try it this way, but you may get coil rub.

http://www.simplyspeakers.com/speaker-repair-foam-edge-replacement-instructions-4.html

 

or you real carefully cut the dust cover out of the way, cut 7/8 around,  leaving  a tab to hold the dust cover on.

tape this back

use shims to center the coil on the poll.

glue the outer part of the surround to the basket.

next day pull the shims.

check for rub.

flip cover back into place and reglue.

next day.....

 

done

[dennismiller55 4,815]

Hey Les, hope I can help.

 

I have done about six woofers and a couple of mids from various manufactures.  I was happy with the results on all.

 

I removed the dust caps on the very first pair I did.  I used shims as called for in the many instructions I found.  I bought a new dust caps with the surrounds.

 

All the rest I replaced the foam without removing the dust caps.  I read somewhere to use a signal generator at 30Hz, 80Hz, 100Hz, 200Hz depending on the size and frequency of the speaker.   Use just enough volume to barely excite the speaker. It will keep the voice coil centered at midrange in its travel.  You use this tone the entire time you are gluing it up and the glue sets.  I did not have a sig gen at the time so I used Audacity to create MP3 tones and put them on my iPod.  I used on old set of ear buds to make a cable.  You get the picture.

 

 

There seems to be a lot of methodes including using a 1.5V C cell.  I think that pushes the voice coil to far out or in.  But some swear by it.

 

 

 

[Circuits & Concepts 320]

I experimented with using coil movement to center the coil, but I went with cutting the dust cover 7/8 of the way around and shimming the coil. I used 24 lb paper strips for the shims.

 

Using Kevin's recommended 3M Plastic and Emblem Adhesive, which cures very quickly, everything is done!  All that remains is to screw the drivers in and clean up the glue on the dust caps.

 

I'll let the speakers set with the cones pointed up as long as my patience will allow (maybe until this evening), then see how they sound. 

Thanks to all for your advice!

 

Cheers!

Les

 

[mbskeam 1,975]

some speakers have a very small air gap between the coil and pole, some are huge, carver woofers seam to be in the middle of this range

its tuff to wait isn't it.....

[sanford lindstrom 35]

I have only refoamed one pair of speakers. I left the dust caps in place everything went back together fine and the result was great.

 

Good Luck. 

[weitrhino 1,443]

I refoamed a pair of Advent Baby II's with less than stellar results. The instructions recommended shimming but did not include new dust caps or give clear instructions on dust cap removal. So I decided not to shim the coils and ended up with one of them rubbing a bit. Both speakers went into a box and have never been used since. One day I'll dig them out and try again. Using shims would seem to offer better results.

[kve777 6,888]

Sorry to be so late to this party!

    I don't remove the dust caps or shim the VC unless there is a spider or cone replacement.

Here's a hint- Index the driver's UP location in the box and install it 180 degrees  from there(upside down) when done, this allows for spider 'sag' over time to start reversing.

 When installing new surrounds- attach the new surround to the cone, let cure for at least 1/2 hour, working the seam good. Sometimes I need to 'block' the cone upwards with cardboard wedges to get good clearance from the frame.

  Then, when attaching the surround to the basket, work the surround contact to the basket and 'feel' for centering. You can manipulate the surround up/down/left/right while it's still tacky. You will see lifting during the first five minutes or so, it's normal. Just keep pressing and massaging the edge gently. Then work it into center. Don't worry about physical centering to the frame at this time. Getting the voice coil centered is paramount! It's not hard, it should mostly get there on it's own.

Funny- I was doing a couple at work today for the guy making the TT weights, old Rockford Fosgate car woofers. Took me 20 minutes! But I've done a few hundred... your first few should take an hour or so. Don't forget- a 50/50 mix of Acetone and Black RTV  makes a great cone and surround treatment. Just brush it on. Let dry. 24 hours, just to be safe.

[Circuits & Concepts 320]

Thanks for your help with this Kev!  And, Happy Birthday!!    !!!

 

Les

[staticvar 56]

Just curious, what model/year are the Advent's?...

[Circuits & Concepts 320]

They're Advent Prodigy Towers.  I'm not the original owner--purchased them at an estate sale years ago.  I estimate they were made in the late 1980's.

 

Les