I’ll just be using lacquer. I’ve become a pretty big fan of lacquer lately – I can get it relatively inexpensively, it sprays well and leaves a nice finish. I’ve used lacquer from Constantines and McFadden, and both have been good. Originally I was going to go with a gloss finish, but I think I’ll end up going satin as the surfaces aren’t quite smooth enough to get a good looking gloss finish.
We used to spray lacquer until we found a few better options. It really just took too long to get the type of build needed. We’d end up spraying 10 coats. We switched to a Sayerlack catalyzed polyurethane. The TU 20 is the basecoat we use and SC 4145 or 4185 is what we use for the topcoat. A coat of the TU20 gets you about 5x as much build as a coat of lacquer. It also sands and powders so nicely when sanded. The topcoat wet sands and buffs very nicely as well and you can get a piano gloss finish very quickly.
you’ll have to check with them. Usually the industrial paint stores that supply cabinet shops have it. I think I pay about $33 a gallon for it and then the catalyst is similar in price. 2.1:1 mix ratio.
After nearly a year I’ve finally finished this project. I just ordered a blu-ray player today, which I think was the last bit of motivation I needed. I gotta have good sound to go with the great new picture – and you can’t have great sound without a monster sub!
Right now it’s set up passive. I have an older QSC USA900 amp that I’m going to try to use, although the fan on it is ridiculously loud. Eventually it will probably be replaced with a Behringer EP2500, which can at least be modified to run quiet.
I’m pretty happy with how it turned out. The curved cabinets were a new experience. I like the look, but holy cow talk about a lot of extra effort! If this were a regular old rectangular box it could have been built in a week instead of a year.
The one thing that’s kind of funny about this sub is that it’s big, but it doesn’t seem as big as it really is. Even in the pictures it doesn’t look nearly as big as it is in person.
Unfortunately I haven’t had a chance to fire it up yet. Tomorrow I’ll hook it up and give it a proper workout. I’ll be sure to pop back in and give a report on how it sounds. I did a test run of it this summer and it shook things pretty nicely, but the cabinet wasn’t well sealed at the time, so I’m expecting even better results this time around.
So I got around to hooking the sub up tonight. The kids rented Horton Hears a Who, which oddly enough has some decent bass moments (I guess you’ll have that with an elephant running around).
So I’ll admit something up front… When I first hooked the sub up this summer, I was a little underwhelmed with what I was hearing. I was hoping it was a poorly sealed box or maybe I had the sub wired up wrong, as there just wasn’t all that much output, especially the really low notes. After just a minute or two of test tones, the amp kicked into super screamer fan mode, which also worried me.
I got the amp second-hand (i.e. FREE), and hadn’t done much research on it. So I went to the QSC site and found the manual for it. I had everything wired up correctly, and I checked the DCR at the terminals, and it was about 3.4 ohms, so I had that wired correctly as well. After a little further reading, I found that the amp has a set of little mini dip switches hidden on the back, one of which engages a high pass filter. Turns out these were ON, so the amp was cutting off everything below 30Hz! I flipped those off and hooked it up to the receiver. I had the gain on the amp maxed, and the reciever’s sub level set to +3dB. I set the speakers all to small, and set the LFE xover to 60Hz. We fired up Horton Hears a Who at a “moderate” level to see what would happen. Holy ! Deep, rumbling bass, but still very well controlled. About 5 minutes later my wife came down and said “That’s all I can take”. I guess it was shaking the windows upstairs.
I built this sub exclusively for HT duties, so I’m honestly not at all concerned with it’s “musicality”. I wanted boom and rumble. Audiophiles will probably turn their noses up at a statement like that, but it’s true. Obviously there’s a difference between mushy rumble and tight gut wrenching slam, which is what this sub has in spades. My last sub was one of the Lambda “LE” PB-15s with a 350W amp, which I always thought was a pretty great combo. This is a whole different league. That combo had a definite limit (admittedly it was a pretty high limit, but you could reach it). This AV15 can crank out the volume! There were brief thumps that were easily 100dB+, and the cone was maybe at 10% excursion. You can tell when a sub is straining, and this thing never even came close. I’m not an extreme SPL kind of guy, but for dynamic moments in movies, it’s really nice to have this kind of massive headroom to completely handle explosions and other effects. Absolutely no compression so those big booms rip right through you. To reach this driver’s limits would take a big amp and painful SPLs.
I’m using the sub in my basement theater room, which is fairly long and narrow – 13’x30′ with 7′ ceilings and closed off from the rest of the basement. So not a huge room. I just plopped the sub in the corner and didn’t do any experimentation with room placement. Eventually I’ll get around to that, and I’ll probably add an EQ unit of some sort (BFD maybe) as I’m sure there are some serious room modes to deal with. However, for the time being I’m thoroughly impressed. Through the whole movie I never had the amp fan kick in and it ran dead quiet, which is a pretty major relief as I don’t see any reason to have to replace it.