There were arguments about microphonics on capacitors from researchers even. But no danger with good caps and good resistors not in a PA cab vibration and dissipation territory. When crossover is outside, is you can tweak to your system, acoustics, and preference. Then move it in, if you had made provisions like a removable trap door in the back.
Just want to say, Planet, that's a good looking speaker.
I think the best box is no box at all. Go with a sphere or a box with minimal surface area on the driver side. Don't mount drivers in tubes. Bracing and damping are important, even in a small 2-way. Driver matching is important not just for symmetry, but also between the woofer and tweeter's tonal signature. At a point, they must hand over frequency response to one another. Usually sticking with one brand for both drivers helps, but not always.
I'll get flamed for this, but using plywood because it has a warmer sound or tone than MDF is just wrong. You're not making a guitar. A speaker box should not resonate at all! The only thing that should move are the driver cones.
Some manufactures are using aluminum baffles today. Saw one speaker a month back that had a 2" sloped milled front baffle. Took 8-12 hours to CNC.
Closest thing to live sound I've ever heard. I think this is the way things are going today in design. Should you do this? Maybe. Should you apply to your knowledge base? Definately.
Lastly, crossover design is important and the must time consuming part of designing a good speaker, 2-way or other. Go active XO if you can!
My 2 cents.
Vince
We use plywood because it is much easier to build a box with no sound of its own. MDF is not very stiff, has high energy storage and the low-level ooze of time-smeared energy kills DDR.
dave
I doubt most DIY'ers would be interested in spending thousands of dollars on CNC time for a pair of speakers.
jeff
Not mounting drive units in tubes is generally good advice but if you hear the active Linkwitz Pluto's set up properly you will know that this is most definately not always a bad idea, in the right hands.
Note Pluto's tubes are very heavily stuffed and the speaker is actively equalized. Yet the speaker is fast (for want of a better word) immediate and open.
If for instance you like the seamless natural delivery of sound and boxless presentation of the best Electrostatics and magneplanars I am confident in saying completely regardless of budget and whatever speakers you have heard and owned you will know pretty quickly that you are listening to one of the best small-medium size loudspeakers you have ever heard.
That's with plastic tubes and ply and (in my case) a tiny amount of mdf.
The secret of building a good 2-way? The crossover, speaker selection for correct Qts (et. al), and cabinet tuning. I did the speaker parameter measurements, did the math, re-did the math, tested, did the math again, tweaked, more math, and what I ended up with sounds like magic. But in the end it's just measurements and math.
I realize there are programs that do the calculations automatically. They cost money. Good thing I like math.
I realize there are programs that do the calculations automatically. They cost money. Good thing I like math.
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I have done alot of work on the baffle, the only thing left is the hole for the bass reflex port, and I will sink it into the baffle like the drivers. I have even used a 45 degrees bevel on the woofer. puh it has been quite tiresome but also fun 
. I tried the fitting today and it was perfect .
. I tried the fitting today and it was perfect .
ReTired2Way?
The 8"/1" two way was a ubiquitous implementation in the '70s and '80s. Several issues contributed to its subsequent paucity. The most important such issue was lobing at the crossover point, because of destructive interference due to distance between the tweeter and the bottom regions of the woofer - a physical necessity that could not be overcome. Cross it higher and lobing becomes worse, not to mention that the plastic woofers of the era go into violent breakup. Cross it lower and the tweeter dies.
I have often wondered if this can be ameliorated by using a larger modern tweeter, with its lower crossover point and increased power handling. Larger tweeters lack response linearity in the top octave because of rim-to-center destructive interference, yet another physical necessity that cannot be overcome. I suspect this is a non-issue for many listeners over 40 or 50.
Pre-CD era tweeters were notoriously easy to burn, and at 20 kHz they t(w)eetered
at the edge of breakup. This is no longer the case. While any self-respecting speaker company would not sell a speaker expressly "made for old geezers" (a more politically correct term may be substituted) a DIYer need not be thus constrained. A shallower profile tweeter, albeit one with narrower dispersion, may ameliorate top octave response droop on axis, and inverted (concave rather than convex, as practiced by Focal and Accuton) profiles may also help here.
I think a crossover point around 1500 Hz is eminently feasible with such a tweeter, especially one with a narrow front plate, provided the middle-aged or older listener does not care much for top octave extension he can not hear anyway. Wavelength at 1500 Hz is around 23 cm or 9 inches, just enough to squeak an 8" through.
Troels Gravesen has done some excellent (as usual) work on larger tweeters. Any practical experience? Salas, do you think that a larger tweeter can make the Tired2Way a ReTired2Way ("retired person's two way") ?!?
The 8"/1" two way was a ubiquitous implementation in the '70s and '80s. Several issues contributed to its subsequent paucity. The most important such issue was lobing at the crossover point, because of destructive interference due to distance between the tweeter and the bottom regions of the woofer - a physical necessity that could not be overcome. Cross it higher and lobing becomes worse, not to mention that the plastic woofers of the era go into violent breakup. Cross it lower and the tweeter dies.
I have often wondered if this can be ameliorated by using a larger modern tweeter, with its lower crossover point and increased power handling. Larger tweeters lack response linearity in the top octave because of rim-to-center destructive interference, yet another physical necessity that cannot be overcome. I suspect this is a non-issue for many listeners over 40 or 50.
Pre-CD era tweeters were notoriously easy to burn, and at 20 kHz they t(w)eetered
at the edge of breakup. This is no longer the case. While any self-respecting speaker company would not sell a speaker expressly "made for old geezers" (a more politically correct term may be substituted) a DIYer need not be thus constrained. A shallower profile tweeter, albeit one with narrower dispersion, may ameliorate top octave response droop on axis, and inverted (concave rather than convex, as practiced by Focal and Accuton) profiles may also help here. I think a crossover point around 1500 Hz is eminently feasible with such a tweeter, especially one with a narrow front plate, provided the middle-aged or older listener does not care much for top octave extension he can not hear anyway. Wavelength at 1500 Hz is around 23 cm or 9 inches, just enough to squeak an 8" through.
Troels Gravesen has done some excellent (as usual) work on larger tweeters. Any practical experience? Salas, do you think that a larger tweeter can make the Tired2Way a ReTired2Way ("retired person's two way")
?!?
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