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.
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.
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…
Does anyone have a picture of the tweeter wire dressing? My NBLs had already been got at before I had to replace the tweeters and the wire layout was different in each. I’ve taken a guess as to what will affect the spring plate the least without the wires touching the walls of the box but it would be nice to know if I got it right.
In my first picture and in the above brochure it looks as though, viewed from the rear, the wires exit the tweeter at 12, go clockwise to 9 and then vertically up into the MF box.
And that one has the sticker with the match group letter on it, maybe I can leave be, except I didn’t have any hylomar to hand when I fitted the new tweeters and I’d always meant to rectify that as I don’t thin Naim would have used it originally if it did nothing.
Thanks for posting these. A fascinating read, especially the Phil Ward interview. As a bonus, I listened to the King Crimson track, mentioned in the Chris Thomas review and really enjoyed it. Just listening to the whole album.
My pleasure James! King Crimson does my head in even more than Pink Floyd though
I’ve had that booklet for many years but can’t remember how I got it. It also contains similar articles on the CDS2 and NAP250 - both really interesting. Then there’s an interview of some bloke by the name of Paul Stephenson, and finally ( rather poignantly ), an article by Paul Messenger entitled; What’s In A Naim? Julian Vereker of Naim Audio (which I’ll read over the Christmas period).
