Any thoughts on how you’d tackle “lightly machining” the secondary lip?
Willy.
I’m waiting for my son to come over and have a closer look but he wants to do it with a cutting tool in a pilar drill - assuming we can create some sort of jig to lock the speaker to. He’s not sure how soft the alloy is yet and that may influence his choice of tool. I will update when I have something to show.
How are you finding the mid range units. As good as the original Naim ones? Any downside to using them?
There was a definitive improvement over the old Mids. Difficult to be to absolutely clear on the relative merits as there’s something amiss in the system at the moment, predating changing the mids and gradually worsening, that I need to troubleshoot. With the ongoing building work the whole house is a bit “Steptoe and son” at the moment. No room to swing a cat let alone dismantle a DBL. My suspicion is something downstream of the preamp but upstream of the DBLs.
Willy.
Maybe just screwing/bolting it to a piece of thick ply with large washers over the mounting hole lands so you can’t cut into them?
Any time I’ve milled aluminium in the past it’s involved a lot of cutting fluid. Partly why I went down the bandsaw route.
Willy.
We’ve now had a chance to look at various options to shave the secondary lip on the replacement DBL mids to clear the isolation maze and have opted to use a little finger sander. This is surprisingly aggressive but doesn’t seem to generate too much heat - if you take it nice and slowly!
A little satin black sprayed on the rear and you’d be none the wiser.
3 Likes
Charlie,
How did you manage to get them matched? Are they just measuring the ohms and matching pairs against this?
@Geko
Not too difficult actually, I kindly asked the chap at . 
Germany Scanspeak to please match them, so he did.
a bit off topic… but can anyone tell me the dimensions of the foam gasket between the base cabinet and the middle (LF) cabinet?
Here’s a bit of an update on my mates DBL’s. I’ve had both of his mid and tweeter boxes and have swapped out the all he drive units for new ones. Shaving the rear lip of the ScanSpeak mids worked perfectly and does not interfere (in any way) with the isolation matrix.
What is good is that this allows me to swap boxes between my DBL mid/tweeter box with the standard Naim speakers and the replacement options he now has.
I can comfortably say that they are, indeed, very close sound wise. I was struggling to say which I preferred. The replacement mids may have sounded a tad warmer/richer but they’d only had a couple of hours running in.
What really surprised me was how much influence the screw tightness had on the tweeters. I found that the screw heads need to just touch the grommet. Any pressure on the grommet and the tweeter sounded quite dull and lifeless.
6 Likes
nobody? 
Hopefully over the next few weeks I’ll be replacing the foam in my DBLs. I’ll measure up the gasket and post the numbers in this thread.
Willy.
2 Likes
Thanks a lot Willy!
I’m sorry I can’t help. I put my bass boxes back together a week before you asked the question.
Thanks Geko, appreciate the thought.
I’m sure I’ll get, sooner or later, what I need 
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