And as a corollary to that, it would argue that the speakers were tuned to the installation by Alfa's supplier.
Indeed, I agree. I think people chuck them out without ensuring that a replacement is better. There's a risk with polypropylene-cone (or other non-paper-cone) speakers having less mid-range response (even though there might be lots of impressive bass and treble), and midrange tends to be the very sound you need when on the road.
I like your approach.
I was never impressed by the plastic adaptor plates. Lots of scope for resonant nasties etc with them.
Thanks. I always admire your work and it inspires me. And, thanks for taking the time to reply.
As for the adaptor plates - I thought they would make things easy - funny how we try and take the easy way out sometimes!
What was the spectrum analyser s/w you use on your iP for this? I'm wondering if there is an Android port. It could be interesting for comparison purposes.
The app is called 'RTA', and I use it with a CD recorded from a pink noise sound file, though it also has a very good noise generator of its own.
No real issue with self tappers into ply. It's a nice strong material.
Cheers. I'm still having issues with self-tappers into clip nuts, as I almost always do. I will try to find some M4 or M5 clip nuts to finish this off nicely.
Varnishing : I did read a good tip many years ago in respect of varnishing ply where the material is not marine ply. The first coat or two ( so the tip went ) should be with extremely thinned varnish. So thinned as to be mostly thinner. The argument was that this allowed the varnish to penetrate the ply better and resulted in the upper layer being impregnated with varnish rather than coated.
Yes - I discovered something similar by accident. I was refinishing a sideboard and the polyurethane varnish went horribly wrong on the second coat - the brush dragged up a sticky mess and I was forced to clean it all off, rubbing with turpentine. I then used another product, but the finish was far more rosy (an amazing shimmering grain effect) than it should have been. I realised it was because of all the hard rubbing with the turpentine - the thinned first varnish had gone right into the grain. Now I start any varnishing with that step - varnish thinned about 75% with turpentine.
I presume you're not refitting the standard covers and leaving the adaptor/speaker on view?
I guess I could, or I could cover the wood with black felt and fit the Focal grille.
But I intend to refit the standard cover shaved down to sit over the speaker - I will probably use small magnets that will pick up on the outer screw heads. I don't think small ferrite magnets will affect the speaker? - considering the speaker basket is a non-ferrous alloy.
Have you plugged the big holes in the door skin? That's one of my projects for this year I also have to complete the fitting of anti-resonance pads to the doors ( driver's side is done, but not passenger side )
No, I haven't, but probably should. I think when the speaker is fitted into the door trim, the holes in the door metalwork (behind the armrest, stitched door card, etc) are of little consequence for the speaker sound quality, though they probably transmit more road noise/electric window noise.
However when the speaker is fitted into the door metalwork, and the door trim is just an 'open shell' over the door, then yes - I think you would find a significant benefit to sealing up the door metalwork. In the past in other cars, I have done this with Dynamat (the expensive way) or floor vinyl stuck on with under seal (the cheap way!) though large holes may need covering with hardboard or similar as well.
While you're there, I suggest bracing the metalwork around the door pull cotton-reel mount. It flexes (and cracks) quite badly there. A piece of 18mm MDF can be screwed on behind with self-drilling screws for a quick and effective solution - but I know you will do something more elegant
I like the way FIAT designed the Stilo doors - and probably most expensive models after the Stilo - where there is a complete metal inner skin sealed and bolted all around the perimeter. The window regulator, guides etc. are built up on the inner skin before fitting to the door. The door speaker is mounted in a pod and sounds excellent. I think this is all because FIAT copied the Mk4 Golf to make the (unpopular) Stilo... the 500 and Grande Punto are a return to standard construction.
The design age of the 916 does work against us sometimes, but the construction (with the lift-off door trim - no annoying Christmas-tree clips - trim made of high-density foam rather than hardboard) is quite nice in some ways, and reminiscent of the old 164 (one of my favourite cars).