Naim NBL, the nested box suspension

My just aquired NBLs have been transported without the packing piece for the nested box so the suspension for one speaker is poor although now present. The other is fine.

I found the manuals and good information on this forum so I have been able to re-space the LF boxes away from the frame.

To look further I need to be able to remove the nested box containing the MF LF units through the front of the speaker cabinet. To do this the black plastic bosses around the 4 speaker binding posts should be pulled out and fall into 2 halves so the red and black posts will go through the holes where the bosses were. Can anyone advise how I do this? Chris
Final question - what finish is this?

It’s difficult to say what the finish is from your picture. Do you have a picture showing more of the actual speakers? Rosewood (Rosenut)?

As for the black plastic bosses, I think they should prise out - indeed it looks as though someone has already tried doing that. Otherwise, I would defer to the experts at Naim on this one. Perhaps @NeilS could ask Clive or someone else familiar with the NBLs at Naim HQ.

Manual here

I think the packing pieces would have gone in the front between the nested speaker and the main speaker, to stop them rattling around, but the transport bolts were in right, for the nested speaker and for the bass units?

The black inserts do indeed encapsulate the sockets & form a tight interference fit into the cabinet. They were tapped home with a nylon mallet, so to remove I’d expect them to put up a bit of a fight! I’d also be concerned about cabinet damage from potential break-out.
As for the finish, hard to tell - one of the darker ones, rosewood or walnut perhaps?

Regards
Neil.

Thanks for the replies, Neil in particular. I think I will leave alone for now and have another go after Christmas if its still bugging me. Thanks again and just another couple of pictures for finish identification. Chris


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That looks like ebony. IIRC some of the final pairs made were this finish.

I just had to carry on with this. I have attached some pictures for reference.
I was unable to remove the black bosses around the speaker posts so I removed the red and black plastic end caps. All but one broke but I had some spares. I removed the nested box (the bare terminals pushed trough the bushes). I tapped the bushes out from the inside.
The suspension is three point and one of the two rear pins was sheared off, I fashioned a new pin for the rear brass bar.
Reassembled. And it works!




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So there is only a single point of suspension on the front? It looks like there is in fact only one position for the spikes in the shoes which is interesting.

If you have not put back together yet please get lots of photos :slight_smile:

What in the end was the issue?

That foam looks in decent nick at least.

I wish I had captioned the photos. Top tp bottom:-
Underside of the nested box with a cup at the front and two pins at rear, one is broken off, top right.
Inside the nested box. Pin at front and flat pads for suspension at rear. Bushes in place.
Bare terminals with red and black ends removed. Black “two” piece bushes.
Refashioned M4 spike from an allen bolt.

Thanks

Always interesting to see inside these things.

I think you can edit your post and add some labels if you want.

Any more photos?

This is very interesting thread. Congratulations on acquiring a pair of NBLs - they are superb loudspeakers!

In your opening post you said “I have been able to re-space the LF boxes away from the frame”. May I ask how you did this? When I had to move my NBLs to another room for decorating, I tried to slide the cardboard inserts in as per their instructions. However, I found the gap had closed to the thickness of a credit card. I did ask Naim for the general assembly drawings so that I could work out how to move the LF boxes, but these were not forthcoming. However, Jason had consulted with Clive who advised that as long as it’s possible to slide a piece of paper in the gap it’s ok. I would still like to understand the design better.

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The the gap at the rear of the LF had been lost by tightening the locking screws with no spacers in place. There is and old thread on here the says how to fix this and it is in the manuals too. This is my experience.

The LF units are held in place by their weight and four brass 10mm nuts under the base which need to be only loosely tight. I accessed these by standing the speakers on 2inch blocks, looseneing the nuts with a socket set, pushing the LF box forward, I managed a 2mm gap at the locking tabs, before gently tighening the brass nuts.

I may eventually take the whole things apart to refoam the cabinat linings and the seals for the LF drivers. But I think the main thing is the nested box isolation and suspension and making sure the LF unit doesn’t touch the frame.

Thanks, I might have a go next time I’m feeling enthusiastic. I must admit, I hadn’t thought to look in the manual - doh!

if you go further get more pics, you are our canary lol.

Just to complete this thread:-
The cloth grills have an inner rubber band sewn in to attach, there is then a further outer band round the outside on top to hide the sticking out bits. These are 4mm for the inner and 5.5mm for the outer.
Nitrile rubber O-ring cord - available from Amazon. Join cut ends with superglue to make a band (big o ring).

I copied this information about NBL ‘O’ rings from a message posted by @NeilS on the previous forum:

“Unfortunately nothing at all left in the deepest recesses of Naim HQ I’m afraid.

The only information I can find is as follows:

Nitrile Cord, 4mm 1320mm

Nitrile Cord, 5.7mm 1220mm

The lengths are per speaker. The thinner one is sewn into the hem of the grille & the thicker one sits around on top, if that makes sense. Each cord is butted together using Loctite 406.”

I’ve an old Naim booklet here which has a review of the NBL and an interview with the designer, Phil Ward. There’s plenty of info in it that would definitely interest NBL owners. I could post it up here if @Richard.Dane is fine with it.

This is the booklet cover and a pic from the NBL article…


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I and various others replaced the foam inside SL2 driver boxes, with good effect on SQ and also got rid of disintegrating decades old foam.

There is a thread on this from a few months ago.

Jim