DrWho Posted April 13, 2006 Share Posted April 13, 2006 I'm the new workshop director for the AES chapter at the University of Illinois and I'm looking to get a head start on some workshop ideas for the fall....one of which will be a suwboofer workshop. Since it's college town, low price is a big plus, but we also don't want to skimp on the performance (otherwise it'd be a waste of time). So here's what I'm thinking and was wondering what you guys thought of the idea: Ascendant Audio Assasin 12" driver ($75): http://www.ascendantaudio.com/assassin12specs.html PartsExpress 250W Sub Amp w/Bass Boost ($120): http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=300-796 The enclosure will be 5 cubic feet tuned to 20Hz and will be using one of the 4" flared precision ports cut down to 14 inches ($13): http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=268-352 The cabinets will be precut by another member's dad off campus so we'll pretty much only have to drill the thing together. I'd figure about $30 per cabinet unfinished. The subamp will be rewired for 3dB of boost at 25Hz (so I'll have to figure out some new values that aren't in the table). Overall the system should have an F3 around 19Hz and put out 110dB. The following plot shows the behavior of the driver with and without system nonlinearities - this is a very reassuring plot as most drivers look way nastier than this. Total cost should be under $250....with student discounts we might be able to swing $200 [H] Quote Link to comment Share on other sites More sharing options...
TheEAR Posted April 13, 2006 Share Posted April 13, 2006 Looks like a serious copntender for best "student" sub under $300. A dorm shaker and war starter. [] Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted April 14, 2006 Share Posted April 14, 2006 that seems like a feasible project. Hmm I might want to model the sub in autocad if you want and give me directions. Right now im too err buzzed..... Quote Link to comment Share on other sites More sharing options...
Spkrdctr Posted April 14, 2006 Share Posted April 14, 2006 When are you going to start selling them?[] It will be fun to see how this works out. Great project and looks to be a lot of fun. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 14, 2006 Author Share Posted April 14, 2006 Probably sometime in the fall semester of 2006...I posted the idea here in hopes that someone might be interested in building one themself. I never thought of selling anything though...that could make for an awesome fundraiser... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted April 14, 2006 Share Posted April 14, 2006 Those Ascendand drivers are pretty impressive for the price. I bought 2 of the Arsenals when they could be had at the preorder price. My son and I built a box for them and stuck them in his van. They totally blow away some of his friends "name brand" subs. Ascendant conservatively rates their drivers so don't be afraid to give them their fair share of current. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 14, 2006 Author Share Posted April 14, 2006 The problem isn't the current so much as it is the cone excursion...the further the voice coil moves, the less B-Field it sees and thus less power in the motor. Attached are some more nonlinear projections - the input power for all the plots were adjusted for excursion limits (besides the yellow one). Light Blue = linear behavior, excursion limited (150W) Dark Blue = voice coil temperature taken into account (95W) Purple = VC temp and 50% drop in B-field (250W) Green = VC temp, B-field, and slightly lower tuning due to port compression (200W) Orange = VC temp, B-field, port compression, and reduction in effective driver diameter (100W) Yellow = ignore everything, throw in full power (350W) As you can see, things quickly turn to crap when you really start pushing the system. But you could still claim +-3dB from 20Hz to 80Hz [] Though it's not apparent, I would anticipate needing the entire 250W from the amp in order to achieve 110dB...which means the system is exhibiting quite a bit of power compression. Fairly linear low distortion behavior will probably end around 104dB. But ya, these are merely projections of what I hope to be the worst case scenario and I'm not sure what other non-linearities can be accounted for, but there has gotta be more. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted April 14, 2006 Share Posted April 14, 2006 Still looks awesome for the ching. What kind of pre-assembled units do you think it will be comperable to? Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 14, 2006 Author Share Posted April 14, 2006 It would be comparable in output to a KSW-12, but dig lower. Two of them would cost the same as a sub-12, same output but would dig lower - the downside is it'd take up twice as much space. It would beat the KSW-10 and the sub-10...and definetly any of the promedias subs. Quote Link to comment Share on other sites More sharing options...
bhendrix Posted April 14, 2006 Share Posted April 14, 2006 What are your plans for cabinet dimensions and material? Will both driver and port be front firing? Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 14, 2006 Author Share Posted April 14, 2006 If it were a cube it would have dimensions of 22" on each side with .75" wood...front firing driver with a front firing port: 4" flared port, 14" long. We were also throwing around the idea of sonotube, but don't want to go to a down-firing woofer as it would reduce maxSPL and cause more nonlinearities. So if it's more cost effective we would go with a front firing driver and a rear firing port with an amp somewhere in the middle. (picture SVS on its side). And finally a triangle design like the RT-12d would be 24" along the sides (34" face) and would be 35" tall. It may seem big, but when tucked into the corner it's a big space saver. Those are the ideas floating around right now...I'll probably build something that is 18x18x33 as it would fit nicely beside my desk. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted April 14, 2006 Share Posted April 14, 2006 the triangle design causes more complications as it takes longer to build those pieces. I asked a tube company how much a 16 inch inner diameter tube is, 12 feet at 3/16 an inch costs 99 dollars free cutting. To think of just cutting the baffle and such would be a cost cutter by a long shot as compared to the triangular sub Quote Link to comment Share on other sites More sharing options...
Xover Posted April 14, 2006 Share Posted April 14, 2006 The triangle sounds like a good option to me. A couple less parallel sides and plenty of room for a passive radiator if you so desired. The face and top could be nice hardwood veneer the other three sides won't show so MDF would be fine. And corner placement usually doesn't offend the decor or mama. Duh-O forgot about amp placement on the corner option...... Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted April 14, 2006 Share Posted April 14, 2006 wood veneer hahhahahahhaahahha in a college seting hahahha! btw amp on top Quote Link to comment Share on other sites More sharing options...
Xover Posted April 14, 2006 Share Posted April 14, 2006 Ok let's make that optional and spend some money on a protective cover for the woof. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 15, 2006 Author Share Posted April 15, 2006 Since it's a workshop, whatever wood cutting needed is going to be done ahead of time in one of our member's dad's woodshop. You could argue the triangle takes less time to cut because there's less pieces and setting angles isn't that big of a deal. It definetly is the least invasive on the room and has the added benefit of no parallel vertical sides. The problem with sonotube is mounting the amp. With a driver on one side and port on the other the amp would need to be flushmounted in some way...and that'd be a lot of work to make airtight. A 6 foot section with I believe a 15" diameter was running $20 at the Lowes in town...talk about a steal. But since we would want it to lay on its side without rolling, I think we could house the amp in a box that has rounds holes in two of the sides through which the sonotube goes...and then you just need a small hole in the sonotube for the amp wires to go through. I'm not too sure what the effects of heat will be on the amp in such a tight space though... A cube would be the easiest, but the problem is it takes up the most usable floorspace. The workshop is actually going to be spread out over a few meetings too...the first couple will be me discussing some of the theory and design considerations involved. Perhaps we might be able to get someone like Tom Danley or Tom Nousaine to come down and talk too...the more "educational" we make these workshops, the more money we get from the school to help bring the costs down. All that to say...I'm thinking we will present a few possible designs and then vote on 2 or 3 of them during the first meeting. The whole point of DIY is the ability to customize so perhaps we'll present a few coffee table, lamp stands, end table options... Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 15, 2006 Author Share Posted April 15, 2006 Oh, I almost forgot....this is one of a few speaker building workshops. All of the designs will be raw wood and it'll be up to the end owner to finish them however they want. Everyone has different tastes and budget constraints - and I kinda like the raw wood look [] Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted April 15, 2006 Share Posted April 15, 2006 maybe because you're a raw kinda person [] eh setting up angles is not as easy as you think Quote Link to comment Share on other sites More sharing options...
keepinitcool Posted April 18, 2006 Share Posted April 18, 2006 That is a pretty cool idea. Some extensions of it could be to built a passive sub and allow the use of external amps (which people might already have), and then build a crossover as an extension of the project. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted April 18, 2006 Share Posted April 18, 2006 can you go for a more space-saving design, say a bit more tower look? 22" cube is almost a LS bass bin- that's pretty darned big! If you want- you can do final assembly over here! Maybe I'll have the fibreglass thing figured out by then and we can 'dorm-proof' them! This Saturday at BS and Woo's should be fun, are you getting off Fri night or coming in way late so's I gotta pour you into the car early Sat am.? We want to get there early in the day so we can spend some time blowing up their stuff! M Quote Link to comment Share on other sites More sharing options...
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