It's been a few weeks, but I've got the pair up and making noise.
Box is 65 liters. A midrange chamber and a vent were made from 4" pvc pipe and fittings. Woofers had a high Qts (0.74), so stuffing was added to the vent to make it resistive. Inner walls of box were lined with recycled denim batting.
The crossover is series - 2nd order on woofer and midrange, but 4th order on tweeter. Crossover points are ~550 Hz and 4500 Hz. Zobels on both mid and woofer. A series RLC notch was added across woofer and mid branches for impedance compensation. A parallel RLC notch was used for a local peak in woofer breakup area. A potentiometer is currently being used to adjust the spl level for the upper frequencies on the tweeter (12 kHz and up). Load is around 6 ohms. Sounds good driven by my KT88/6550 tube amp.
I'll enjoy it the way it is for a few more days before I shatter my illusions with microphone measurements.
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The prototype boxes are made from scraps leftover in my shop. Everything needed for the build was also here, except for some of the pvc pipe fittings.
Construction will be similar to my amps or other previous speaker projects. I like to use different kinds of wood on each project. Pics below show white ash with teak edges on small full range speakers, and padauk with walnut edges on my h/p amp.
I have some rosewood boards which I'd like to use on the edges of the finished boxes. Haven't decided yet, but I'm considering some kind of veneer for the main panels. Maybe tigerwood, canarywood, black locust, or mahogany, or . . . ?
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I'll enjoy it the way it is for a few more days before I shatter my illusions with microphone measurements.
Here are the SPL and impedance measurements. SPL response matches very well with the LspCad simulation. My cave is just big enough to get on-axis and 15 deg off-axis at about 7 or 8 feet back. Not much difference between them, so only showing on-axis. Near field woofer is spliced in at 500 Hz.
Best estimation is that SPL is 85 or 86 dB, so the plot was scaled accordingly. Impedance is fairly benign, even in the (aperiodic) vent region, so my 6-8W SET amp does ok.
Wish it had a little more headroom for some classical and other dynamic material. I guess it's the Iron Law at work. Also is a plot of the acoustic phase, taken from the simulation. I was very happy with how well they lined up.
My impressions of the sound? Very detailed and natural sounding, and easy to listen to. Even at lower listening volumes, different instruments are clear, in symphony or big band material, for instance. The 10" woofer has plenty of presence. This track brings a smile when it's cranked up. ;^) ("Lay It Down", Ritenour and Scoville)
YouTube
Overall, I am pleased with the project. I used up some of the drivers in my stash, made a reasonably sized box (65 Liters), learned about aperiodic vents, and ended up with something that sounds good on my tube amp.
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Vzaichenko and Jeff ODNF.
It's alive but not finished yet!
Still plenty of remaining work.
Playing as it now.
Inside to an Simpelstark amplifier. - YouTube
It's alive but not finished yet!
Still plenty of remaining work.
Playing as it now.
Inside to an Simpelstark amplifier. - YouTube
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mkane77g,
Congratulations on your successful build!
That is a different take on the chassis with the the sinks acting as the "top". Was this driven by aesthetic reasons or it's an effort to lower the height so that it will fit in a particular spot?
What height did you end up with?
Just wanted to use a box I had on hand. heatsinks sort of fit so I used it.
Height is 4 -1/2". Heatsinks hover right around 53° C.
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