Saturday, May 13, 2017
Matrix-like interior bracing
Wednesday, June 8, 2016
The cutting begins!
After weeks of practicing turning the Sketchup designs into tool paths using the trial version ov VCarve pro, I finally started cutting the wood. Although the design may have to be tweaked as I learn more about using the Shopbot, the first session was more productive than I expected. I cut all the matrix bracing stays (vertical separators) and did an experimental cut (one that after a few minutes was clearly wasn't going to work).
The laminate panel (chipboard and 1/4" finished plywood looks like it worked much better than I had anticipated. The rolling on the the glow and lots of clamps seems to have done the trick. The only issue is a gentle warp which makes cutting difficult as the sheet has to be very firmly secured to the sacrificial board. And there is a tendency to break though the tabs if there aren't enough of them.
These two videos show the Shopbot in action. It is remarkable to see the finished pieces taking shape. It's as if, after staring at them for months on the screen in the CAD program, they were being slowly beamed1 down from the virtual world of Sketchup.
What was also gratifying was that the toolpaths worked exactly as envisioned. Of course that was perhaps a little less surprising since VCarve has a very sophisticated preview for exactly that purpose.
(Note the passage of time - the first was show at about 3pm, the second at about 6pm. Some of that was testing and altering tool paths, but the cutting does take some time).
The only remaining question is the 45 degree cut at the top of each panel. Since they are still fairly firmly attached to each other, I might try using the router here....
1 Gratuitous Star Trek reference
The laminate panel (chipboard and 1/4" finished plywood looks like it worked much better than I had anticipated. The rolling on the the glow and lots of clamps seems to have done the trick. The only issue is a gentle warp which makes cutting difficult as the sheet has to be very firmly secured to the sacrificial board. And there is a tendency to break though the tabs if there aren't enough of them.
These two videos show the Shopbot in action. It is remarkable to see the finished pieces taking shape. It's as if, after staring at them for months on the screen in the CAD program, they were being slowly beamed1 down from the virtual world of Sketchup.
What was also gratifying was that the toolpaths worked exactly as envisioned. Of course that was perhaps a little less surprising since VCarve has a very sophisticated preview for exactly that purpose.
(Note the passage of time - the first was show at about 3pm, the second at about 6pm. Some of that was testing and altering tool paths, but the cutting does take some time).
The only remaining question is the 45 degree cut at the top of each panel. Since they are still fairly firmly attached to each other, I might try using the router here....
1 Gratuitous Star Trek reference
Friday, May 20, 2016
Waming up
Thais may be a trick of the mind but the bass response seems to get better after about an hour's continuous use. I wonder whether the rubber suspension is cold and stiff but as the bass driver imparts energy to it, it warns up and becomes more supple?
If so, I need to ensure that I calibrate all the drivers after playing music through them for a significant period at the kind of volume I intend to listen at.
If so, I need to ensure that I calibrate all the drivers after playing music through them for a significant period at the kind of volume I intend to listen at.
Saturday, March 26, 2016
Pick up the thread
August 10, 2011 - that's when I finished building the Phase IVs - was 1690 days (or 4 year 7 months) ago. But today I took the first concrete steps in the next phase; I bought some of the wood I need for the Phase Vs.
The woofers AC 250F1s I've had for 4 years. I was going to use Hiquphon OW1 tweeters but at $250 a pair I decided instead to go with the Vifa D27TG-45-06s, the same ones I used in the Phase IVs since I bought 6 of them during the last build (not sure why).
I had been thinking about the AC 130F1 for the mid driver but they didn't seem, on paper anyway, much better than the Scan Speak 15m-4624 I already have (from the MkIII project). First, it's cheaper to get a second Scan Speak than two AC130s and the Scan Speak has a circular chassis which makes routing it into the baffle much easier.
So what was once going to be a no-compromise final build has turned into a more incremental evolution (though I know it will probably be the last iteration).
I'm experimenting with panels made of plywood glued to fiberboard. I need to figure out how not to damage the veneer on the panels while I'm building the enclosures. Other than that next weekend it's off to the races.
The woofers AC 250F1s I've had for 4 years. I was going to use Hiquphon OW1 tweeters but at $250 a pair I decided instead to go with the Vifa D27TG-45-06s, the same ones I used in the Phase IVs since I bought 6 of them during the last build (not sure why).
I had been thinking about the AC 130F1 for the mid driver but they didn't seem, on paper anyway, much better than the Scan Speak 15m-4624 I already have (from the MkIII project). First, it's cheaper to get a second Scan Speak than two AC130s and the Scan Speak has a circular chassis which makes routing it into the baffle much easier.
So what was once going to be a no-compromise final build has turned into a more incremental evolution (though I know it will probably be the last iteration).
I'm experimenting with panels made of plywood glued to fiberboard. I need to figure out how not to damage the veneer on the panels while I'm building the enclosures. Other than that next weekend it's off to the races.
Tuesday, March 1, 2016
About time
It's about time I started work on the Phase Vs. I have an all-wood design completed, and an idea for how I will build them; I just need to buy the wood (and the tweeters) and make a start...
Saturday, June 21, 2014
One year on
Just realized it's a bit over a year since I replaced the SUV-6; and I still haven't remeasured the speakers, let alone redesigned the crossovers.
Friday, June 14, 2013
Out with the old, in with the new
My first amplifier I bought in 1979, a Technics SUV-6. I'd saved up for a set of B&W DM7s eventually decided to get a second hand pair of DM6s. So then I needed an amp. Mr Robinson, the Bowers & Wilkins salesman (the retail shop was I think already a separate business from the speaker division by then) suggested the SUV-6 and so that's how I ended up with it - along with a Technics SL150 turntable and an SME 3009 Series II tonearm. The only other change in my setup until this week was a Linn (ex demo from Grahams HiFi in Camden) with an Ittok which replaced the SL150+SME in 1987.
That is until last week, when my trusty SUV-6 finally gave up the ghost. It's fixable I think but the input switch has been getting more and more temperamental for several years and last week it decided to stop working altogether.
Knowing I wasn't going to have time to fix it for a while, I decided to take the plunge and buy a new amp. I did some estimates and figured for the GBP 200 I paid in 1979, with inflation and the exchange rate, I should be spending between $1,200 and $1,600.
So instead I looked for the cheapest reasonably well reviewed integrated solid state amp I could find. And so plumped for this (bottom of the pile in the pic), the Yamaha A-S500, a B-stock factory reconditioned unit for $319. And I was in for a bit of a surprise.
I had always rather poo-poohed the notion that amps could really do much to alter the sound. After all it's simple a case of taking a signal and making it louder. The scope for 'error' was far lower than in the engineering of a turntable or a cartridge. And speakers, clearly have a huge impact.
And was I wrong! The A-S500 is rated as 85W into 4 ohms, compared to SUV-6's 70W, but it's much wimpier. But that's only the beginning. It's completely lacking in bass compared to the SUV-6. On my Phase IV's there's almost nothing there below about 150Hz. The 31Hz open B notes in Becker's "11 Track of Whack"? The bass player appears to have taken the day off.
But suddenly the DM6s sound a bit more like a modern speaker - brighter and without the smiley face response curve. I haven't done any tests yet, but I suspect the new amp has flattened out the DM6 curve.
And that's is a bit of a problem since it suggest that the SUV-6 was as much a part of the smiley face as the speakers - and I used it do calibrate the Phase IVs and build the crossovers. Ugh!
On the plus side, I can always go back to individual driver testing and redesign the crossovers; which I will undoubtedly have to do if I want to continue to use them with the A-S500. But if I repair the SUV-6 then I'll need the current crossovers. Not to mention that I am still thinking of getting a cheap tube amp at some point, and it's not clear how that will change the picture. And of course I've got the Phase Vs on the drawing board which I'll start building when...
I may have to build external crossovers that are matched to a speaker amplifier pairing.
Damn! Lots of work, lots of variables, not enough time (or money).
Knowing I wasn't going to have time to fix it for a while, I decided to take the plunge and buy a new amp. I did some estimates and figured for the GBP 200 I paid in 1979, with inflation and the exchange rate, I should be spending between $1,200 and $1,600.
So instead I looked for the cheapest reasonably well reviewed integrated solid state amp I could find. And so plumped for this (bottom of the pile in the pic), the Yamaha A-S500, a B-stock factory reconditioned unit for $319. And I was in for a bit of a surprise.
I had always rather poo-poohed the notion that amps could really do much to alter the sound. After all it's simple a case of taking a signal and making it louder. The scope for 'error' was far lower than in the engineering of a turntable or a cartridge. And speakers, clearly have a huge impact.
But suddenly the DM6s sound a bit more like a modern speaker - brighter and without the smiley face response curve. I haven't done any tests yet, but I suspect the new amp has flattened out the DM6 curve.
And that's is a bit of a problem since it suggest that the SUV-6 was as much a part of the smiley face as the speakers - and I used it do calibrate the Phase IVs and build the crossovers. Ugh!
On the plus side, I can always go back to individual driver testing and redesign the crossovers; which I will undoubtedly have to do if I want to continue to use them with the A-S500. But if I repair the SUV-6 then I'll need the current crossovers. Not to mention that I am still thinking of getting a cheap tube amp at some point, and it's not clear how that will change the picture. And of course I've got the Phase Vs on the drawing board which I'll start building when...
I may have to build external crossovers that are matched to a speaker amplifier pairing.
Damn! Lots of work, lots of variables, not enough time (or money).
Subscribe to:
Posts (Atom)