2 pairs of Heybrook HB3's that sound very different !!?

[a91gti]

It seems so obvious that I'm sure there is a very good reason it has not been suggested yet but as Jose has two pairs of this speaker why not just swap the damaged units for the good ones?

[Shane]

Perhaps he wants two pairs that work!

[a91gti]

Maybe, if he doesn't its the easiest and cheapest way to repair a pair of speakers that aren't all that. Get one good pair and flog the other to some punter.

[pre65]

Originally Posted by a91gti

Get one good pair and flog the other to some punter.

With a suitably accurate description of course.

[a91gti]

Of course Philip, I would never suggest otherwise. ;-)

[JwEs]

Taking longer than I wanted. Yes, I'd like two pairs of these, would be awesome wouldn't it
At the time, I got the foams to do the replacement on the black ones but then found out the diaphragms of the mids are all sticky. So I'd like advice on how to handle that before going further.
Also, found out why one of the brown ones is producing different sound, the damage wasn't just huge bumps on some corners, some of the panels unglued on some places with transportation! Maybe there's some internal damage too, maybe even on both even if the other one doesn't seem to be unglued. I'll take more pics and update the thread soon, but would like to finish the refoam of the black pair's mids first. What's the cause of that sticky thing anyway ?

Thanks all
José

[Shane]

That's quite surprising. The mids were coated in a sticky dope when received from SEAS, so that's exactly how they should be, but I would have expected the stickyness to have dried out after 30 years!

If you decide to dismantle the speakers completely to sort out the cabinet joints, you should be able to just glue some 1" square battens inside the corners, although the top corner behind the mid-range enclosure will not be easy to get at. The reduction in cabinet volume won't be significant. Take careful note of how the damping foam is fitted in the cabinet, and if there are any bituminous panels on the inner surfaces (can't remember now if the HB3 had these. The HB1 and HB2 certainly did) check that they're still well fixed. If not, use a contact adhesive to stick them back. Once you have the mid-range units repaired and everything is back together, check that the mid-range enclosure is airtight by pushing the bass unit gently inwards. If the mid-range unit moves out at all, then take out the bass unit and check where the mid-range leads go through the side of the mid-range enclosure. As far as I can remember, there were a couple of variations. Some had individual wires passing through individual holes in the enclosure wall and sealed with some sort of mastic gunge (can't remember what exactly, but it shouldn't be too hard to improvise), others used a round section sheathed twin-core cable passing through a plastic cable gland. Of course, you may choose to re-wire the whole thing, in which case you just need to make sure that the cable entry is air-tight. If the cabinets really are falling apart, then you would also need to check where the mid-range enclosure seals against the front and back of the cabinet.

If you do any rewiring, be very careful if you need to solder new leads to the tweeter. The solder lugs are mounted on plastic which melts very easily, causing the lug to fall off. It's sometimes possible to repair if this happens, but it's a sod of a job.

When you put the bass and mid-range units back in, don't be afraid to tighten them up hard, and go back a week or so later and tighten them again. This also applies to the crossover mounting panel, but definitely not to the tweeter. If you over-tighten that, the bolt head will go straight through the plastic face-plate!

The HB3 was always the hardest of the original Heybrook range to get the best out of. Put them in the wrong place with the wrong amp and they can sound thin, hard and lacking in bass. I ran mine for years with an A&R A60 which was OK, but couldn't exploit their dynamics. I'd love to hear them on the end of a modern valve amp with a bit of welly like the WD88VA. They're not inefficient, but they do like a bit of power in reserve. Not surprising really when you consider that most of the development work was done using EAR 509s. If you can get hold of a pair of those, they'd really sing!
Ideally, they should be on open-frame rigid stands about 10" - 12" high (if you find a pair of HBS3s, then so much the better), with their backs against the wall away from the corners in a large reasonably well-damped room. From what I know of the Algarve, tiled floors and big windows are popular, so some thick rugs and voluptuous sofas would probably not go amiss!

Let us know how you get on, and lets have some pictures!

[Shane]

I just went back through the thread to check a couple of details and came across something that puzzles me. The tweeters in the black pair look different from the ones on the brown pair. The brown ones are definitely the originals, the others look more like the current SEAS Prestige range. I wonder if the originals were blown up at some stage? Could be an improvement. The same drive units were used in all versions of the HB3, so if these are different, they aren't original.

[JwEs]

@Shane
Those very detailed posts are awesome! Thanks, I guess this could be a reference thread for anyone restoring these. I finally did the refoam on the black pair and have a few other questions but first to answer your question on the tweeter. To answer your question about the tweeter differences I took it off on both pairs and they're exactly the same reference. The only difference I saw was that the black pair has only 3 allen screws whereas the brown one has six. I'll later post pics of the brow pair on this thread as I slowly continue with the ordeal. Just taking one thing at a time...

So now that I got the foam rings replaced they now sound a lot like the brown pair! Guess it was the mids not working properly.

Few questions:
1- How important is it to put back the damping material around the mids that's lose inside how it was before ? And on the woofers ?
2- I got a pair of original stands! But how should the speakers be fixed to them ? I noticed the area where they stand on the stands has the veneer deteriorated and sticky which leads me to believe they were glued somehow..
3- When I replaced the mid rings I took off the drivers and had to solder the wires back. The wire that goes from to the connection plates to the coil changed color due to the high temperature. Does this make any difference ? It was a pain to solder because the hole metal assembly of the driver acted as heatsink, you get the picture...
4- The paper on the drivers (check pics bellow) got a few wrinkles when I refoamed them, does this affect the sound ?
5- Finally, most likely no important but the glue that's on the diaphragm of the mids has some debris and is not sticky anymore in some places is this ok ?

It's taking it's time but I'll get there!

[Shane]

Nice job! Answering you questions in order:

1) The wool stuffing behind the midrange driver should be evenly distributed along the length of the midrange enclosure, but make sure it doesn't touch the back of the cone. As far as the woofer is concerned, the foam should line the sides and back of the cabinet. I can't remember if we put wool behind the woofer as well, but if we did, then again it should be distributed evenly. It was a long time ago...

2) The weight of the speaker is enough to secure it on the stand. The stands were supplied with thin foam tape to stick on the top just to stop the speaker sliding around. It's probably residues of this on the bottoms of the cabs. A couple of little bits of blu-tak would do the same job.

3) & 4) Can't really comment on what effect these would have, but if they sound ok, they ARE ok!

5) No, not important at all. You'd do more harm than good removing it.

Happy listening!