"NEW" PLANS CV earthquake sub-horn +infra upgrade! |
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tv00
Old Croc Joined: 10 August 2009 Location: Denmark Status: Offline Points: 1886 |
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Posted: 27 December 2010 at 8:18am |
Hi everybody. I'm working on quite a sub-bass-project project and have the space for a permanent installation
New plans First of all I have measured the long type of cv l48se, I think it's called "E-type", of wich i own 8, i own 6 of the short as well. Here's the "old" plan found on the internet so far: Here's the "new" drawing of the original longer l48e plan: I can come up with better drawings for the "new" ones, 4 of mine are 47,5 cm wide (inside) the others 57,5 cm adapting rear chamber: Second of all i installed a mounting plate(grey fill) for the royal turbomax 1500i, this will allow for the extended excursion of the rtm1500 driver PLUS it blocks for two parts of the rearchamber decreasing the rear chamber volume to 79 Liters in the slim cabinet, 95 Liters in the wide. I figured this would be better looking at the chamber of the TAS monolith sub designed specifically for the rtm 1200 / 1500. / 74Liter rear. I didn't try hornresp or calculating the rear chamber, but I've read that "A number of different formulas exist for compression chambers, and any one of them may not give the best size for your application. These formulas should be considered a starting point." found here: http://www.rocketsciencecanada.com/rocketsciencecanada/Sound/Horns/Info_Design.asp Building horn mouth extenders Third: to make the horn play deeper i plan to build horn mouth extenders inspired by this: The plan for a test is to do a "wall installation" stack two boxes vertically up with TWO pieces of ply instead of one to get an exit angle above 45 degrees to properly "push out" LOW FREQ! I tried to plot the horn expansion into a spreadsheet here: https://spreadsheets.google.com/ccc?key=0AoF_TP2LxpYZdG5aN0pFeWdhQ2kyQzhBVFBldVhCMWc&hl=en&authkey=CL3RitwH Doing exponential regression calc came up with a formula / graph.I hope to find a good way to calculate the mouth extension. According to the information I could find the horn should be tuned to 18 hz. Any suggestions? Practical test: I plan to do a practical test: with the mouth extension, I plan to set it up so that I can alter the angle and listen / measure. But first I need to make new hatches; the long horn is loaded from the front, but the space is too narrow for rtm1500 to get in! -but i can start the mouth extension test with the original cv 189E. Theoretical calculation / sims: I try, but please ANY help from you smart guys to make this work will be very much appreciated! regards from Denmark! Edited by tv00 - 27 December 2010 at 2:45pm |
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Meat
Old Croc Joined: 05 June 2009 Location: Manc Status: Offline Points: 1514 |
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Dear tv00 ,
I'll get in there before anyone else says this: there seems like quite a lot of wasted space in the new sub. Just to be clear is this a new build starting from sheets of ply or a modification starting with the cabs you already have? If it is a new build I have to say theres probably designs already around that will probably go lower, however there is nice symmetrical loading and no 180degree bends in the design so it might sound very nice indeed. Another thing you might want to consider is making the corner reflectors at the back a touch bigger or curved as there is negative expansion at the back corner currently. Would you like it simulated or have you already done this already? Andrew |
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Don't test the champignon sound
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tv00
Old Croc Joined: 10 August 2009 Location: Denmark Status: Offline Points: 1886 |
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@meat:
I didn't build these! The "new plan" is an original box design from Cerwin vega, it's only "new" in the sense that the plans haven't been posted on internet before, my only edit is the driver mounting plate marked with grey -it makes room for extension & blocks 2 parts of original rear chamber. I got it far cheaper than the price of the ply and they're very well build! You say that other design go lower, I don't think I've seen any going to 18hz as it is said these should with the mouth extension. You're right about the "wasted space" with the mounting plate in place, but i guess it's better this way with a smaller rear chamber? -originally all of the space left is a part of the rear chamber. But I think the space is better used in the long version as the horn is longer, throat smaller and rear chamber smaller I would VERY MUCH like it simulated as I have not tried that, a sim can give information on: -rear chamber size -dimensions of mouth extension. Edited by tv00 - 27 December 2010 at 2:46pm |
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tv00
Old Croc Joined: 10 August 2009 Location: Denmark Status: Offline Points: 1886 |
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I just tried to model it in hornresp.
There's some of the T/S specs that I don't know which is why I took some valujes from scoop / monolith sims with rtm1200 Still i need to fill in some fields, this sim is without mouth extensions. I doesn't go too deep though; getting big excursions below 40hz. This "earthquake cinema sub should go deeper according to various sources and my real-world measurements with cv 189es drivers; it doesn't appear to have this steap low cut-off Seems that i need to fill in some throat chamber information? First try hornresp: http://i56.tinypic.com/2134t8l.jpg Edited by tv00 - 27 December 2010 at 6:22pm |
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FlipC
Young Croc Joined: 25 October 2007 Status: Offline Points: 654 |
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Build a SPUD instead.
Or D210 |
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tv00
Old Croc Joined: 10 August 2009 Location: Denmark Status: Offline Points: 1886 |
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Not really any help when i have 14 of these!!!!!!! These are 1500w rms / piece 48"x48"x24"
If i was to build something else i would probably calculate a horn for permanent installation under the stage Edited by tv00 - 28 December 2010 at 1:06pm |
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FlipC
Young Croc Joined: 25 October 2007 Status: Offline Points: 654 |
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Ah I missed what the use was for.
Thought it was a HT setup. |
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happy chicken
New Member Joined: 04 January 2011 Location: australia Status: Offline Points: 1 |
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Hi all.
I also own 4 of these big Wbins, the long throat version. Ive got the drivers to build 4 more but i havent been sure whether to keep this design. They are very big and for their output, it seems like another design would be more practical. But they do have a very smoth sound and pump some low end but not quite enough for their size, i would agree with the sim model frequency response curve 35 - 110 Hz, But ive never got that sort of spl from them. if there was some sort of alteration that could be made so the go lower that would be awesome. Im about to build 12 tuba30 but with 15" drivers. I was planing on crossing those over from 60hz and the Wbins 60hz down. How can we make these bad boys go lower. |
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dj degenerif
New Member Joined: 27 July 2011 Location: amsterdam Status: Offline Points: 1 |
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maybe this is something for you ,
i have one original CV sensurround w bin 2x 18 inch. http://www.cerwin-vega-fans.com/forums/viewtopic.php?f=13&t=2903 Edited by dj degenerif - 27 July 2011 at 2:47am |
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salzburgsoundsystem
Registered User Joined: 27 January 2011 Location: Austria Status: Offline Points: 200 |
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You may face a challenge there. If I recall correctly, the T30 is designed to fit 10" and 12" speakers. Regards, Ben |
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VECTORDJ
Young Croc Joined: 11 June 2006 Location: United States Status: Offline Points: 513 |
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Has anyone tested any of these NEW 148E s yet??? I think... on the net some where I saw photes of one without the top on??? VECTORSONICS
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Wrek0ne
Young Croc Joined: 10 February 2011 Location: Cambridge Status: Offline Points: 749 |
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What is the volume of the current wasted space? I was thinking of a double 15 push pull design a few weeks ago and it looked similar. Food for thought?
Do yo have sims of what horn resp does for the original design?
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Poll this!
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