Don't want to get too off track here, but what is the state of the Linkwitz Transform today? Last I was looking into this stuff was about two years ago. Is the circuit available as an inexpensive plug/play compliment to an existing plate amp? Or at least simple to incorporate on the board? Two twelves for the price of my single eh? You want to poison any hope for settlement on this matter don't you? 
I've viewed films in a few home theaters on 90+ inch screens with pretty spectacular subwoofers and surround channels in operation and while satisfying in some sort of faster, more powerful, 0-60 thrill seeking regard, the whole experience just seemed fundamentally out of balance to me, like a housecat with a lion's roar (and I suck at simile). Maybe more like a moped with a harley engine. Ok, no better.... but you get my point.
I've got a 50in plasma television and I watch movies via the internal speakers and a diy 10in powered 1.5ft sealed subwoofer in a slim flat box tucked under the television stand out of sight. Even that sub is set as I described above in this thread; It just extends the internal speakers. 99 percent of home theater lovers would reject this with a shudder of contempt. But I think it's precisely right for the size of my screen and dimensions of my 12 x 20 x 8 living room. And I'm definitely a movie "lover" who logs a lot of hours watching. If I'm still around when wall sized 8'x12' LCD becomes an affordable installation for middle income types like myself, then I'll be talking subs to match the experience. As long as I'm viewing "reality" through a 50 inch rectangle the audio shouldn't jar too overwhelmingly with that "reality".
But again, I realize my tastes aren't anything like the norm.
I seem to have an unpopular take on the home theater experience. If I'm there in Florida witnessing a live launch of the space shuttle or viewing a blockbuster adventure film near front center of an IMAX theater, then visceral thunder is pretty much a natural accompaniment; an expectation that needs to be satisfied.
I've viewed films in a few home theaters on 90+ inch screens with pretty spectacular subwoofers and surround channels in operation and while satisfying in some sort of faster, more powerful, 0-60 thrill seeking regard, the whole experience just seemed fundamentally out of balance to me, like a housecat with a lion's roar (and I suck at simile). Maybe more like a moped with a harley engine. Ok, no better.... but you get my point.
I've got a 50in plasma television and I watch movies via the internal speakers and a diy 10in powered 1.5ft sealed subwoofer in a slim flat box tucked under the television stand out of sight. Even that sub is set as I described above in this thread; It just extends the internal speakers. 99 percent of home theater lovers would reject this with a shudder of contempt. But I think it's precisely right for the size of my screen and dimensions of my 12 x 20 x 8 living room. And I'm definitely a movie "lover" who logs a lot of hours watching. If I'm still around when wall sized 8'x12' LCD becomes an affordable installation for middle income types like myself, then I'll be talking subs to match the experience. As long as I'm viewing "reality" through a 50 inch rectangle the audio shouldn't jar too overwhelmingly with that "reality".
But again, I realize my tastes aren't anything like the norm.
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Honest to god I didn't go looking for this. Just after I posted the above I dropped by avsforum following a google search for applications using that Dayton 12in DVC and saw this in the same thread there.
Joking aside, even though this television is well shy of the, I don't know... 90inch average ? of the more serious HT setups, it does illustrate the point. Watching Transformers, or Black Hawk Down, on the above might just test the limits of anyone's willing suspension of disbelief.
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Somehow... I just don't see why the toddler that belongs to that toy bucket needs to be evacuating his bowels in terror while watching Franklin the Turtle on a 24 inch set.
Joking aside, even though this television is well shy of the, I don't know... 90inch average ? of the more serious HT setups, it does illustrate the point. Watching Transformers, or Black Hawk Down, on the above might just test the limits of anyone's willing suspension of disbelief.
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actually, I'm all for subtle. my personal HT uses a single 12, the old 315-88 in a 4.25ft^3 box port tuned to ~18Hz it rolls off nicely ~4db per octave and is very musical and accurate at low levels. The bonus is I can watch movies at night without upsetting the neighbors and still get a visceral experience because of the clarity at low frequencies/spl.
But, It can keep up with my 7.1 system flat to 110db, 60hz to 90Hz... which is frightening. I've seen friends jump over the couch during LOTR 1 when the bad guys army starts marching.. from a sitting position (which is funny). Having something that can do both is nice to have.
But, It can keep up with my 7.1 system flat to 110db, 60hz to 90Hz... which is frightening. I've seen friends jump over the couch during LOTR 1 when the bad guys army starts marching.. from a sitting position (which is funny). Having something that can do both is nice to have.
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I used a dead blow hammer and hardwood block to separate the cabinet today. All tongue in groove and dowel pinned. Fortunately all the glue was brittle enough to separate without taking any wood with it. There was a piano lesson book wedged in a bottom corner with the owner's name inside and dated June 1915. It's at least that old.
It is solid oak. Appears to have been a file for 12in 78s? There is a bar running along the back of the shelves that limits their depth to approx that of a record album. May be a bit of sacrilege to cut 4inches off of the height, but it doesn't have any markings describing its provenance or manufacture and I doubt that it's terribly valuable.
Maybe in another 100 years some dude will have it on the antiques roadshow and be told that it might have been worth big money if an obvious idiot around the turn of the century hadn't turned it into a loudspeaker. Oh well, I could get sentimental and change my mind.
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If the ViFa has the right specs for the box size... sure. looks like a nice driver.
With that big cavity in front of the front mounted driver behind the door, you'd have significant "cavity effect" which is a resonant chamber in the lower 100's of HZ. That's no good. down firing is what I'd do. I'd also put in cross braces near but not at the center of the cabinet, from the middle of each side to the middle of the opposite side, and I'd glue and clamp them together where they cross. Glue the door shut and add wood around the crack on the inside if necessary. The internal volume may well be bigger than is optimal for the Peerless woofer. You should find out what internal volume makes it happy, and put in a solid shelf to adjust that right. With a closed box, the internal volume isn't nearly as critical as with other designs. I'd also glue foam rubber or some other acoustically absorbtive material tight to the inside walls of the cabinet, especially in any corners. With a sealed cabinet, you can force the acoustic output to be flat to 20HZ with active electronic EQ ahead of the power amp (make internal volume slightly smaller if you are going to do that, for a smoother tighter bass rolloff before EQ. Very worth it if you can handle the electronics. I am using the Peerless XLS 12 inch woofs and love them. They have a bigger Xmax (voice coil travel) than most 12 inch woofs that I've looked at. Very important if you ever want to take them down to 20HZ flat. What a great Oak cabinet!
That was suggested elsewhere in the form of a Linkwitz Transform. I haven't been reading up on this in a few years. I'm pretty comfortable with basic electronics and repairing/replacing components on boards, including smd's. Is there an LT circuit available that I can integrate onto the board of my existing 100w sub plate amp? Actually I have two of the 100w plate amps so I can bridge/combine for more power if the LT circuit demands it.
A large part of the fun of DIY for me is maximum value for the dollar. Got a couple of plate amps at that NHT sale a while back. This woofer was marked down almost 2/3 (granted it was overpriced?) and the oak cabinet for 10 (granted stripping/refinishing will be work but that's enjoyment for me).
Returning, while I'm still able, the Vifa in exchage for the Peerless is looking more and more attractive. Equal to the Vifa musically, with sufficient extension for any future use should I wish to "go there" with it.
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Uh oh... just went back down that rabbit hole of "subwoofer equalization circuits" via google search and my brain is squirming. Back to basics for this project me thinks.
But I do see the problem posed by the likelihood of creating a resonant chamber there.
Maybe bottom firing may be the way to go. I could go rear firing, but that limits placement by disabling the option to place it against a wall.
But I do see the problem posed by the likelihood of creating a resonant chamber there.
Maybe bottom firing may be the way to go. I could go rear firing, but that limits placement by disabling the option to place it against a wall.
Damn. I really want to keep this from looking like a big subwoofer in the living area. Rear and bottom firing are out. The box, unchanged dimensionally, has 4.2 cu ft of volume to work with before calculating for driver and bracing.
So here's the latest idea. Side firing RSS315HF-4 12" behind an art deco grille. Amp on bottom. Grilles on both sides so that it looks like plain ornament from a distance instead of a speaker grille.
art deco side firing 12.jpg
So here's the latest idea. Side firing RSS315HF-4 12" behind an art deco grille. Amp on bottom. Grilles on both sides so that it looks like plain ornament from a distance instead of a speaker grille.
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Damn. I really want to keep this from looking like a big subwoofer in the living area. Rear and bottom firing are out. The box, unchanged dimensionally, has 4.2 cu ft of volume to work with before calculating for driver and bracing.
So here's the latest idea. Side firing RSS315HF-4 12" behind an art deco grille. Amp on bottom. Grilles on both sides so that it looks like plain ornament from a distance instead of a speaker grille.
art deco side firing 12.jpg
That too is a nice idea but the amp needs to be on a vertical side so natural convection will pass over the heatsink fins.
Hi pb,
I think your box would work just fine as in your Post #36. For the Linkwitz transform cirucit I'd recommend: Linkwitz Transform Subwoofer Equaliser.
Have you given any thought to using a 4th order bandpass (sealed back chamber with tuned front chamber)?
Regards,
I think your box would work just fine as in your Post #36. For the Linkwitz transform cirucit I'd recommend: Linkwitz Transform Subwoofer Equaliser.
Have you given any thought to using a 4th order bandpass (sealed back chamber with tuned front chamber)?
Regards,
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