I was lucky enough to be donated a box of stuff from Vikash, the remnants of his MadAboutSound sales venture, (he's now given up diy as he's utterly happy with his Orions, and sees no need to play any further 
) Amongst the stuff, and stay tuned for some further info), was a single FR125, so a centre speaker was the obvious choice. After extensive modelling, I opted for a 9l sealed enclosure, chosen as it allows me to port it at a further date if required, yet gives a good all round response.
Now you may be wondering where the experiment comes in all this. Firstly, it's the first full range speaker I've ever built for myself, and secondly, I chose to use this as a test of my veneering skills, as I wanted to try some Vavona burr I've had in stock for many years. This is very fragile, highly figured wood, that moves and splits as soon as you look at it, but looks spectacular. I've had great success with simpler veneers before, and wanted to use this for up and coming projects, but needed to know how it works.
So the box. Fairly simple, 18mm MDF construction, (as I had offcuts lying around), extensively braced internally, dimensioned to fit straight onto an existing bookshelf holding paperbacks, stuffed with 200g of long haired wool. Notch filter at 1K1 to tame the slight rise in response there. No BSC as it will be flush against the wall/books.
Veneering. This stuff is awkward. I used my usual technique of powdered resin, (Extramite) adhesive applied with a roller, veneer added, then solidly clamped. Though I'd dampened and flattened the veneer first with a press, it still moved during glue up, and during handling and clamping bits of burr tended to pop out or edges break.
So, after veneering was finished I had to go back and patch in several holes and cracked edges. I also found because of the extreme grain, handling once veneered, and before final sanding, was required too be very delicate, as the edges would crumble at the slightest excuse. This meant after first sanding I had lots of bits to patch, and though I matched the dry wood quite well with the filler, after oiling and waxing, a few bits still showed up so will need further attention once I find my colour fill crayons.
Anyway, I'll stop wittering on now, and show you a pic...
) Amongst the stuff, and stay tuned for some further info), was a single FR125, so a centre speaker was the obvious choice. After extensive modelling, I opted for a 9l sealed enclosure, chosen as it allows me to port it at a further date if required, yet gives a good all round response.Now you may be wondering where the experiment comes in all this. Firstly, it's the first full range speaker I've ever built for myself, and secondly, I chose to use this as a test of my veneering skills, as I wanted to try some Vavona burr I've had in stock for many years. This is very fragile, highly figured wood, that moves and splits as soon as you look at it, but looks spectacular. I've had great success with simpler veneers before, and wanted to use this for up and coming projects, but needed to know how it works.
So the box. Fairly simple, 18mm MDF construction, (as I had offcuts lying around), extensively braced internally, dimensioned to fit straight onto an existing bookshelf holding paperbacks, stuffed with 200g of long haired wool. Notch filter at 1K1 to tame the slight rise in response there. No BSC as it will be flush against the wall/books.
Veneering. This stuff is awkward. I used my usual technique of powdered resin, (Extramite) adhesive applied with a roller, veneer added, then solidly clamped. Though I'd dampened and flattened the veneer first with a press, it still moved during glue up, and during handling and clamping bits of burr tended to pop out or edges break.
So, after veneering was finished I had to go back and patch in several holes and cracked edges. I also found because of the extreme grain, handling once veneered, and before final sanding, was required too be very delicate, as the edges would crumble at the slightest excuse. This meant after first sanding I had lots of bits to patch, and though I matched the dry wood quite well with the filler, after oiling and waxing, a few bits still showed up so will need further attention once I find my colour fill crayons.
Anyway, I'll stop wittering on now, and show you a pic...
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Looks good Al How does it sound? I'm guessing a full range will make a very nice centre channel speaker, should be good for voice inteligibility!
I know what you mean about chipping off bits of veneer. I had enough problems with my blackwood, mostly at the edges when sanding, or flush trimming.
When you dampened and flattened the veneer, did you use any glycerine? I found it worked wonders for making the veneer less brittle. I think from memory I used 10% glycerine 90% filtered water.
Tony.
How does it sound? I'm guessing a full range will make a very nice centre channel speaker, should be good for voice inteligibility! I know what you mean about chipping off bits of veneer. I had enough problems with my blackwood, mostly at the edges when sanding, or flush trimming.
When you dampened and flattened the veneer, did you use any glycerine? I found it worked wonders for making the veneer less brittle. I think from memory I used 10% glycerine 90% filtered water.
Tony.
Never used glycerine, I'm not sure where you could buy it in this country.
Haven't really listened to it yet, just the odd bit of music and test tones. If I get all my housework done I may fire up the system and watch Das Boot, (my usual test disk for surround, and a cracking film as well), later.
Haven't really listened to it yet, just the odd bit of music and test tones. If I get all my housework done I may fire up the system and watch Das Boot, (my usual test disk for surround, and a cracking film as well), later.
Never used glycerine, I'm not sure where you could buy it in this country.
apothecary, perhaps?
Well, I've found several suppliers of glycerine, health shops selling for around £10 for 500ml or 2.5l from a chemical supply house for £15. I'll put it on the list for when I have some cash spare.
As for the speaker, I'm quite impressed. Of course it doesn't have the same sensitivity and extension at the bottom and top as my existing three way, but what it does do it does very well, and I can live with it quite happily in my little, (4x4m) living room, especially as it's about 1/5 the size of my existing centre. I'm not sure it would work quite so well in a bigger space though.
As for the speaker, I'm quite impressed. Of course it doesn't have the same sensitivity and extension at the bottom and top as my existing three way, but what it does do it does very well, and I can live with it quite happily in my little, (4x4m) living room, especially as it's about 1/5 the size of my existing centre. I'm not sure it would work quite so well in a bigger space though.
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