DrWho Posted January 30, 2006 Share Posted January 30, 2006 Is this "rest of the attic" the area above the HT? If so then I think you've got yourself a great IB situation [H] You might want to wait a bit to see how well the new Ascendant IB drivers turn out....The only other option on the market right now is the Dayton IB15...I don't think any of the old school options are being made any more. Just outta curiosity, what is the absolute loudest you'll find yourself listening at? Quote Link to comment Share on other sites More sharing options...
Tom Adams Posted January 30, 2006 Author Share Posted January 30, 2006 Is this "rest of the attic" the area above the HT? If so then I think you've got yourself a great IB situation [H] You might want to wait a bit to see how well the new Ascendant IB drivers turn out....The only other option on the market right now is the Dayton IB15...I don't think any of the old school options are being made any more. Just outta curiosity, what is the absolute loudest you'll find yourself listening at? Looking at the 2nd photo....if you were to walk past that big silver return air duct, go another 10 feet, then turn to your right, that's the "rest of the attic" that you'd see. So no, it's not above the HT room, just adjacent to it. Hope that makes sense. As for the loudest....that's a good question and one I really can't answer. If I had to guess, I'd say 90 to 95 db continuous (based on how loud the test tones "seemed" to be during speaker level setup) with peaks maybe 110???? Does that sound (no pun intended) about right?? Guess I'll dig my meter out for the next movie and have it hold the highest peak (assuming it will do that - never tried). BTW, what can be had for those dimensions I gave? Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 Ya, I'm not getting the relative locations of everything...someone help me out? lol If I get this correct, your HT really is "in the attic" and you've built a room within the entire space? So all the open attic area we're seeing is behind the HT? And then there are narrow sections running down both sides? Like one foot wide?Is there no usable space between the flat cieling of your HT and the peak of the roof?The goal of an IB is have an "infinite" volume behind the driver so that the rear pressure wave has no affect on the driver. Mounting subs like this in the side walls with that narrow space is going to defeat the advantages making the driver behave just like a standard closed subwoofer...So I suppose you could try to build an IB in the rear of your room, but I have two concerns with that. First of all, I hate having the subwoofage in the back. No matter how good the subwoofer system is, you're still going to know the subs are behind you....whether it be the ever so small distortion artifacts, or the mere fact that you can feel the sound hit your body from the rear instead of from the front. Secondly, you have a door between the HT and that part of the attic...and air is going to "leak" through. I'm not sure how big of a concern this would be - like are we talking 1dB or 10dB, but with that amount of air being displaced I can guarantee your door is at least going to vibrate. Maybe we can get creative and try to tune the door as a giant passive radiator [] So ya....how well does that door seal and how firm is the latch?So maybe for experimental purposes you can try your KSW in the rear and see how big of a concern these things are for you. I'm not trying to say it's not doable - just pointing out areas where you are moving away from the "ideal' (whatever that is) so that you can make a more informed decision as to the direction you would like to go. It's like trying to choose between a lamborgini or a ferrari (both are going to be a lot of fun to drive) []Btw, the sides walls would be a doable compromise as well...(two subs per side at the midpoint of the room. One firing forwards, one firing backwards, both facing into each other where a vent out of the side enters the room). In fact, I would think this would be better than a single IB in the rear of the room... Quote Link to comment Share on other sites More sharing options...
Tom Adams Posted January 30, 2006 Author Share Posted January 30, 2006 All your concerns about doing an IB is what has me thinking that I'd like to stick to a "box sub". If I decide I need crazy bass later on, I can still start whacking holes in the sheetrock (boy.....I can just see the wifes' face when I do THAT! LOL...). So, let's limit this to the box thing. Okay by you?? Oh....and you had the relative location of things correct. [] Tom Quote Link to comment Share on other sites More sharing options...
Tom Adams Posted January 30, 2006 Author Share Posted January 30, 2006 27? I can draw some autocad blue prints if dr who tells me l w h, internal brace, ports etc You draw it up and I'd be forever in your debt sir. [] Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 Is it okay by me? lol, it's your room [] So....2x3x2 = 12 cubic feet (I plugged it into a calculator this time) [] One quick question...if you went with a pro amp, would fan noise be an issue? With all that space surrounding your HT we could totally install the amp behind the wall (and then implement a trigger to power the amp on and off). What would you think about getting a custom made driver and enclosure built for you? http://www.tcsounds.com/ci_what_you_get1.htm And here's the pricing: http://www.tcsounds.com/ci_pricing.htm I'm thinking something like the 18" B option....go for an F3 below 16Hz with a target SPL of 124dB (with both subs running, which would only be 118dB per driver). The biggest reason I would suggest this route is they also provide you with a "powered filter module" which would provide any form of EQ that we might want to implement. And I'm sure they would be more than willing to cut back on the price a bit if you wanted to build the enclosure yourself (which would make shipping a ton cheaper too). The deal almost seems too good to be true...I wonder if there is a minimum order restriction or something like that. But you're looking at $2700 + shipping. If you wanted to save some money, we could go with a 15" B option....an F3 around 20Hz with the same 124dB target. That would cost you $1770 + shipping. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 30, 2006 Share Posted January 30, 2006 I rather have a ferrari over hte lamborghini. Also the blueprints are easy. How good are you with a router since I build some extremely crazy bracing! If you want me to go easy on you and make some easy build bracing that's fine. Also DR Who needs to tell me. Also I noticed PartExpress is having a sale with the Dayton subs. There like 25% off! so..... Buy like dual or even two dual subs and have stereo subs behind the cornwalls for around 1500 dollars. with amp and wood price. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 If you went with subwoofers on the market, I would go with one Tumult 15D2 per side - F3 of 12Hz (anechoic) and 118dB maxSPL. Or you could go with two Titanics per side yielding an F3 of 20Hz and 124dB maxSPL. decisions decisions.... Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 30, 2006 Share Posted January 30, 2006 how did you come up with a f3 of 12 Hz with the tumults? what size enclosure etc etc? Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 12 cubic foot enclosure tuned to 13Hz and 3dB peaking 2nd order highpass filter at 16Hz. The amplifier pumps out 450 watts per driver to yield a max volume of 112dB at 16Hz (apparent amp volume is 450, but you'll put 350 for the system input power - the difference is due to the EQ). The best part is the thermal compression improves the frequency response of the system (go ahead and model 100K on the voice coil temp rise). Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 30, 2006 Share Posted January 30, 2006 your porting the tumult? some things just cannot be done without a massive 6 inch flared.... Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 But of course, we have 12 cubic feet to work with...I went down the list of drivers this afternoon and the tumults outshined everything as far as LF extension and the daytons actually dominated in the max SPL (because you can put two drivers per side for a total of 4). Anyways, no need to port the cabinet - at those frequencies you would have mega port overload even at low SPLs. Thus why you go with a pair of these per cabinet: http://www.acoustic-visions.com/~acoustic/products/passive_radiators/stryke_pr18/ To achieve the 13Hz tuning point you will need to add 200g of weight to each driver (simple screw on things...) 4 x $125 each comes to $500 for the passive radiators. 2 x $600 each comes to $1200 for the Tumults (http://www.acoustic-visions.com/~acoustic/products/subwoofer_drivers/adire_tumult_15/) 1 x $500 for the amplifier (Behringer EP2500 comes to mind: 1300watts bridged into 8 ohms) (http://www.behringer.com/EP2500/index.cfm?lang=ENG) That brings the total to $2200 and we would still have to implement the active filter to provide the peaking 2nd order high pass before the amplifier. And then of course build the cabinets... Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 30, 2006 Share Posted January 30, 2006 Wow Dr.Who that mimicked my 16 cubic foot design almost. Though 4 cubic feet less and 2 prs less. Utterly the same..... Heh also Kyle Richardson, the owner of Acoustic Visions goes below msrp.... you can negotiate [] Also I would say qsc plx amps come to mind though more $$$ Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 30, 2006 Share Posted January 30, 2006 btw one fundamental mistake you made... it is 2 by 2 by 3. It is impossible to add 4 pr onto the 2X3 side... the pr are yes 18 inches but are really 19 including frame. so 19+19 = 38 which is > than 36...... Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 30, 2006 Share Posted January 30, 2006 Impossible he says....heh heh heh [] I'm gonna put a 15" driver on that same baffle too.... (btw, it is one 15" driver and two 18" PR's per 12 cubic foot cabinet). Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 31, 2006 Share Posted January 31, 2006 umm holy shit...... I was thinking one 12 cubic footer..... two 12 cubic footers.... make sure to get some big men to carry them in!!! Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 31, 2006 Share Posted January 31, 2006 tuning point maybe 13 I got 11 hz but then remember the f3 is rather high at 26 hertz..... You also run out of passive radiator excusrion at 11 hertz and damn near touch xmax at 16 hertz using only 600 watts per driver. Definitely need a high pass cutoff at 12 hertz min. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 31, 2006 Share Posted January 31, 2006 You need to add 200 grams to each driver and make sure you're using the 1600 ones (not the 2500). The peak PR excursion comes to 32mm and they can handle 38. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 31, 2006 Share Posted January 31, 2006 gah 1600 gram pr bah!!! also there xmax is 38 they can probably stand a bit more Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 31, 2006 Share Posted January 31, 2006 gah 1600 gram pr bah!!! also there xmax is 38 they can probably stand a bit more Are you implying 1600 is bad? (technically it's 1800 cuz of the extra mass added). And no they can't handle any more excursion - I talked to Deon about that one. You really don't want to overpower the PR's as they WILL go flying across the room. Quote Link to comment Share on other sites More sharing options...
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