sfogg Posted October 23, 2004 Share Posted October 23, 2004 John, "Below that, its' 12dB/octave attenuation. So if Fs is 30Hz, it's 12db down at 15Hz.----------------" Depends on the subwoofer. Sealed subs tend to roll off second order but ported (or horns) roll off fourth order. Shawn Quote Link to comment Share on other sites More sharing options...
Q-Man Posted October 23, 2004 Share Posted October 23, 2004 On 10/23/2004 4:15:55 PM John Warren wrote: Altec did something like this in the early 80s. I have the literature on it somewhere. It was a large 4ft x 4ft x 2'ft high sort of thing with an amp. Then I must say that Altec did it wrong. There are certain measurements that work with the human body, and other dimensions that we just grew up with and are used to. A coffee table must be 15 to 16" high or it will feel awkward to us. Have you ever walked up a step and tripped, because it was the wrong height? We have a comfort zone that were used to lifting are foot to. We also have been conditioned to our surroundings. One inch off in the height of a step is critical. You may not know what the height of a step should be if I was to ask you, but you would know if it was wrong or not once you used it. A coffee table is designed for comfort when bending over from a sofa or chair. Beleive it or not, it was also designed to be comfortable to prop your feet on. In my house that's where my feet go. If I was to build a coffee table subwoofer, I wouldn't want any clues to lead people to believe that it wasn't a coffee table. I could go on and on about design and proper dimensions, because that's what I do. Your lucky that I'm being called to dinner now. Later. Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 23, 2004 Author Share Posted October 23, 2004 Q- All right already. Now I'm going to have to dig the brochure up from the archives! I'll be back. Shawn, I was reffering to the driver mounted on an infinite baffle. You are correct however. The vented box is 4th order (24dB/oct) below Fs, sealed is 2cd order (12 dB/oct). Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 23, 2004 Author Share Posted October 23, 2004 ---------------- On 10/23/2004 4:50:27 PM Q-Man wrote: Then I must say that Altec did it wrong. A coffee table must be 15 to 16" high or it will feel awkward to us. ---------------- 36" x 36" x 16" You are "spot" on! The Altec LF-1, 12" vented woofer, 80Hz crossover. In 1982 it was $700. So Altec did nothing wrong. 1982 was a good year- Cornwall $531 Heresy $336 Belle $1119 LaScala $722 Klipschorn $931 (less than the Belle!) Bose 901 $1325/pr. Ohm F $2000 A pair of 901s in 1982 was almost as much as a pair of Klipschorns! Quote Link to comment Share on other sites More sharing options...
Q-Man Posted October 23, 2004 Share Posted October 23, 2004 JW, I should have know that Altec did their homework, now you go do yours. I know that you have a lot of work to do now to figure out the optium box volume and port size. I'm very interested in the output that beast will have at 20Hz, because I may want to try one. If it's less then I want then I'll discuss two in a box with you. If I end up building a coffee table sub from your work, I will see if I can build you a knock down version at no cost to you, if you like. This way I can ship you the pieces. Lets see what happens. I never realized that Bose was so expensive. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 23, 2004 Share Posted October 23, 2004 Bo$e was ripping people off since that long! Anyone taking a pair of 901's and not K-Horns must have severe hearing problems. Shows $$$ does not always equal sound quality. Quote Link to comment Share on other sites More sharing options...
dantfmly Posted October 23, 2004 Share Posted October 23, 2004 ---------------- On 10/23/2004 6:43:51 PM TheEAR wrote: Bo$e was ripping people off since that long! Anyone taking a pair of 901's and not K-Horns must have severe hearing problems. Shows $$$ does not always equal sound quality. ---------------- they,ve been doing it longer then that. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted October 24, 2004 Share Posted October 24, 2004 JW, how much was the McCauley and where did you purchase it from? Quote Link to comment Share on other sites More sharing options...
killerbee_vr6 Posted October 24, 2004 Share Posted October 24, 2004 Thoughts on the McCauley v the North Creek Leviathan? Quote Link to comment Share on other sites More sharing options...
michael hurd Posted October 24, 2004 Share Posted October 24, 2004 I was at the north creek site the other day, and they do not list the leviathon any more. This was a custom spec Aura 1808 with lower efficiency and a much lower fs. Quote Link to comment Share on other sites More sharing options...
formica Posted October 24, 2004 Share Posted October 24, 2004 ---------------- On 10/23/2004 2:32:19 PM Q-Man wrote: That means a coffee table cabinet will work, back to the drawing board. ---------------- From the dimensions and performance mentioned... I'm guessing we are looking at a vented sub with a "EBS" (Extended Bass Shelf) alignment? One of the things that concerns me with "furniture" subwoofers is the lack of placement flexibility given it's dual use (ie: coffee table has to be in the middle of the room or end table at the end of the sofa, etc...). The center of the room may or may-not be the ideal position for a sub... even if you intend on EQ'ing it. Room nulls can easily devastate a subwoofers performance. BTW, it's also a concern I have for the IB I'd like to build... but it's exact position can be tuned a little before installation with some RTA room measurements. Although for some people 18ft3 can pass unnoticed in their listening room (I haven't seen pics of Johns room, but I would agree that 18ft3 would fit into Qman's ) it's not a luxury everyone can allow. I guess that is why we so many in-efficient sub drivers which don't require large enclosures... and why even klipsch has concentrated on building relatively compact models. Different tradeoffs will satisfy different people, as subwoofers are all about compromises. I'm shopping for a pair of K-horns... and fear my current sub won't be enough for the improved transients. I'm hopping to eventually add an IB that will allow me to have some pretty serious "scalable" acoustic output... Rob PS: Although not on par with the McCauley driver... the Adire Maelstrom (for John.. Vas 460 , Qes 0.29, Fs 20Hz, BL 19.8, Xmax 13.0 mm one way) can be an interesting alternative for those on a more limited budget (it's about 1/3 of the price). Both seem to have similar design objectives (a high efficiency 18" LF driver)... but the Adire looses some maximum output and low frequency extension but requires a slightly smaller enclosure. Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 24, 2004 Author Share Posted October 24, 2004 ---------------- On 10s Quote Link to comment Share on other sites More sharing options...
sunnysal Posted October 25, 2004 Share Posted October 25, 2004 its time for the big gun... check out this baffless sub woofer from adire: http://adireaudio.com/TextPages/ParthenonPageFrameText.htm bizzare! At $4-5k for a finished unit it would compete nicely with the Velodyne DD-18 (king of th ehill right now IMHO) I wonder if it works? tony Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 25, 2004 Share Posted October 25, 2004 This Adire motor when used with "only" a 36*36" piston should leave a DD18 in the dust,even free air it displaces so much air no single conventional driver can compete. Problem is,would you like to have this thing in your room,floping up and down.Fanning the room Not me,unless a proper space would be custom built for this device,in the floor with a stealth grill.Then the unit is viable. Better go with a IB design and use one or two 18" woofers,or better build a stealth box(in the form of a table or furniture,even up to 20 cubit feet is not a problem) I will soon deign my own Adire Pathenon killa,...purhase a 250T hydraulic piston,purchase a high speed high pressure pump and design my own controller.Adire's 48*48" will be nothing compared to my planned 100*100' membrane! Quote Link to comment Share on other sites More sharing options...
J.4knee Posted October 25, 2004 Share Posted October 25, 2004 Q-Man/John W, PLEEEEEEEAAASSEE keep us posted on this project. I am extremely interested in the coffee table solution idea. That would be the perfect answer for me. So any dimensions on the box and port and port location would be fantastic. Pictures would be pretty awesome too. This thread definitely has my interest. Thanks!! Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 27, 2004 Author Share Posted October 27, 2004 For an F3 of 26Hz, the air volume in the enclosure (Vb) has to be 18.9 cubic feet (total enclosure volume minus port volume, braces, speaker volume, amp). The port has a 46.7 square inch area with a depth of 10.9 inches. Output is -6dB at 19.7Hz. For F3 of 29Hz, Vb is 12.4 cubic ft, port area is 53 sq. inches and depth is 16.9 inches. Output is -6dB at 23Hz. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted October 27, 2004 Share Posted October 27, 2004 I run two of these in BassMaxx B1 bass horn cabinets for my home theater. The folded horn cabinet brings these in over 100dB efficient because the cone doesn't have to move so much anymore. Now pump the power to them and you can shake the house - literally. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted October 27, 2004 Share Posted October 27, 2004 Here is the latest pic where the subs are laid flat in the corners of the room. The vintage JBL's in front are no longer there. Quote Link to comment Share on other sites More sharing options...
neomartic Posted October 27, 2004 Share Posted October 27, 2004 WOW! That looks really sweet! I'd love to hear something like that! Great work! Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 27, 2004 Share Posted October 27, 2004 Wardsweb, Very impressive,your folded horn subs must sound quite efortless at all listening levels.And those panels you have,some high class there. Now that is a system!Good work Quote Link to comment Share on other sites More sharing options...
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