Allen HC-12 Woofer Foam Surrounds

[OrganistAnthony]

Greetings all,

Using the info in jbird's sticky along with with some YouTube demonstrations, I have successfully refoamed 4 of the Peerless mid-range drivers on my first attempt. I opted to use the kit from the Speaker Exchange in Tampa, Fl. as it seemed like it might be more likely to be a perfect fit on the metal frame. No problems with that kit at all, but now that I have some experience I'd probably opt for the Parts Express surrounds next time to save some money. I didn't bother to cut the dustcap, use the shims, ect. and didn't have any problems. The HC-12's I own have the woofer with the accordion surround and paper cone.

Since I had success with this first project, I opted to buy two more HC-12's that were available inexpensively and locally that I would like to put on the antiphonal relay of my MOS 301. They are a bit different in design with what looks like a polypropylene cone on the woofer and foam surrounds. I looked through some old posts for the 15" woofer foam and didn't have much luck. Could someone point me in the right direction? Also, will it be necessary to cut the dust cap and shim the voice coil on these larger drivers? If so, I'll need to get new dustcaps as well.

Although the 301 has only 2 channels, my hope is that by adding an additional set of speakers I can get a better sense of "spread" in the sound. (and can turn it off on the relay tab when I'm playing at low volumes) I'm curious as to what other's thoughts are regarding the doubling of audio channels to achieve this effect. I have played around with the speaker placement a bit, turning them backwards which I thought was helpful when the organ was played dry. But now that I'm using a reverb unit (Lexicon MX-200) I think I prefer the sound facing me as it is already "virtually" mixing with the artificial space. Perhaps I could have it both ways with the addition of two more speakers. I will gladly welcome any comments or thoughts on speaker placement to get the best sound. I live in a small loft apartment where the console is downstairs and the speakers are above my head behind a railing upstairs, projecting into the small, but lofted area and facing me as I play. I also have a pair of presence projectors in the mix as well.

[myorgan]

Anthony,

Congratulations on your success with the mid-range surrounds. I ended up purchasing from Simply Speakers based on recommendations here, but just received them yesterday. I'll probably post with my experiences.

Regarding speaker placement, now that you have a wet mix, I wouldn't necessarily direct the sound toward myself, but would at least have them bounce off some surface before the sound reaches my ear. Direct sound from the speakers can be the most damaging to one's hearing, even if pleasing.

The only need to cut the cap in the center of the speaker is to shim the speaker during the surround replacement, and make sure it is centered on the coil. If there is no damage to the coil from the speaker flopping all around before you replace it, there shouldn't be an issue just dealing with the surrounds, especially if there are pieces of the surround still hanging on. They will serve to center the speaker until you replace the surrounds.

To date, we've never had to remove the dust cap to replace a surround. In fact, I've never seen anyone remove the dust cap until videos I viewed in the last week or two. I would think there might be more of an issue with excess glue from the replaced dust cap dripping into the coil. I'm no expert, but my mantra is, "If it ain't broke, don't fix it!"

Hope that helps until the experts weigh in.

Michael

[Admin]

I also found it unnecessary to remove the dust cap and shim the voice coil when replacing the surrounds.

[John Vanderlee]

For those 15" drivers I never buy new dust caps. As I explained earlier, I cut the perimeter of the cap - carefully with a utility knife - and cut it so it has a little pattern that lets me fit it back on like a puzzle piece. There is usually not enough old foam material left to "center" the cone, so I prefer to use the shims. I had one bad experience where I the voice coil was rubbing after the repair, so I rather pay it safe.
The old cap gets fitted back in place and the cut gets covered with a bead of the black adhesive that the speaker repair vendors sell. Do it carefully and you hardly notice the difference.