I am attempting to resurrect a pair of NBLs (with SNAXO 362 but no passive xovers) that I acquired for essentially zero net cost. One has a blown tweeter (0 ohms DC resistance) and the other has a blown mid (3.2 ohm DC resistance but the cone barely moves - suspect overheated voice coil). Thanks to information from previous posts on this forum I have acquired direct replacement tweeters (Scanspeak D2010/8511100) and substitute mids (Scanspeak 15W/4424G00). To move forward I have several questions that I would be grateful for some help with.
On the existing tweeters and mids I see some gasket compound that appears to be blue/green in color. Am I correct in assuming that this is Hylomar Universal Blue and is there any recommendation of how much I should apply to the new mids and tweeters?
On the rear of the mids there is a piece of black foam material with two rectangluar pieces of aluminum attached to it. I assume that this is the âdamping weightâ that I have seen referred to in other posts. Should I attempt to transfer this damping weight to the substitute mids and if so, do you have any advice on how best to accomplish the task?
For those NBL & DBL owners that are using the substitute Scanspeak mids I would be interested to hear your thoughts after living with them for some time. Are you happy with the sound or do you feel that that they are not really an effective substitute?
Yes its a damping weight, not sure if those using the scan mid have transferred theirs, but a forum member took a dbl mid to scanspeak and they found it to be an almost perfect match, probably not maditory but I would try and attach it. I think naim used a very strong rubbery double sided tape. Failing that I giess hot glue on the rubber behind the weight would work, assuming you were able to remove the damping weight with the rubber in tact.
No real alternative as the naim mids are long gone. I heard that its a great replacement but some cutting of the basket frame is required for the decoupling slots in the nbl baffle to still be effective. Quite a bit of work, but nblâs would be worth it.
Not sure where you are located, but rubber gasket that holds the cloth covers on can be replaced easily after you have made repairs. Available at Home Depot for a couple of dollars. Good luck, NBLs active are very musical speakers!
Iâm using the Scanspeak mids in my DBLs. No complaints.
I did modify the profile frame of the Scanspeak mids to replicate that of the original Naim units but ISTR someone else taking a different approach possibly by grinding away the rear of the chassis where it might interfere with the cabinetâs integral suspension.
Thanks Willy. Good to hear that you are happy with them. I have not heard NBLs before so have no baseline. One benefit of having to go active with them is that with the SNAXO I can tweak things a bit. Yes, while I think your approach is more aesthetically pleasing when the grills/covers are off, for my NBLs I think I will take the approach of thinning down the outer lip on the rear. Still trying to figure out how to fabricate some protective jigs and which method I will use to remove the material. The previous posts on this forum have been very helpful.
I 3D printed a pair of jigs to the required profile, bolted them around the driver and then used a bandsaw. Iâm happy to share the files for the jigs if youâre interested. They should work equally well for protecting the driver whilst filing.
I performed the mid replacement. I used a jigsaw to cut them to the required size of the old ones using a 3d printed template.
They are âokâ. Some of the sparkle is missing they are rather too polite. I put the originals back in for now.
A similar (but not identical) mid driver was used in the Naim centre speakers which may be a better option.
I also 3d printed identical frames to the black surround of the speaker drivers and made them into speaker covers affixed with magnets, soo much nicer than the dog eared cloths.
Willy, Many thanks for the offer but I do not have ready access to a 3D printer. A resin 3D printer is very high on my wish list though for my scale model hobby! Just concerned about all the issues with toxicity and venting. I do have a Dremel drill stand so I thought I might see if I could remove enough material using a cutter and a lot of overlapping plunge cuts.
Christopher_M, You are correct! I am a Scotsman born and bred but have been living in the US for the last 24 years (Texas first and now Michigan).
garyi, Thanks for the info. I did wonder about the centre speaker mids. They seem to be pretty rare on this side of the pond.
Yeah I donât think the more expensive Naim centres were massively popular. Shame, I have one and itâs great and obviously integrates superbly with nbls