2x beta 12" cab help |
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duppy conqueror
Registered User Joined: 21 March 2015 Status: Offline Points: 46 |
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Posted: 29 May 2017 at 2:26pm |
I have bought 2 eminence beta-12a driver that I want to put in a dubbel box to run 90hz - 200hz
So my skills isnt the best at Winisd, but what I got was that the box needs to be at a volume of 370 liters. Seems like a very big box or? Am I on the right way? Please help me :) want to get this soundsystem running for the summer Here is the winisd text I got: Driver : Eminence beta-12a Vas : 120,0 Qts : 0,46 Fs : 47,00 SPL : 98,00 -- Project for : you -- Number of drivers : 2 Box type : Vented Box size : 370,1 l Tuning frequency : 41,09 Hz Vent : 1 vent(s) 30,73 cm length for each 150,0 x 1062,0 mm rectangle Relative Freq Gain SPL [Hz] [dB] [dB] 90,00 0,00 101,01 95,00 0,00 101,01 100,00 0,01 101,02 105,00 0,01 101,02 110,00 0,01 101,02 115,00 0,01 101,02 120,00 0,02 101,03 125,00 0,02 101,03 130,00 0,02 101,03 135,00 0,02 101,03 140,00 0,02 101,03 145,00 0,02 101,03 150,00 0,02 101,03 155,00 0,02 101,03 160,00 0,02 101,03 165,00 0,02 101,03 170,00 0,02 101,03 175,00 0,02 101,03 180,00 0,02 101,03 185,00 0,02 101,03 190,00 0,01 101,03 195,00 0,01 101,02 200,00 0,01 101,02 Edited by duppy conqueror - 29 May 2017 at 4:45pm |
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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Firstly, the WinISD text you've copied in references a different driver, so you may want to start by checking you're actually modelling the right thing.
Second, the Delta 12 has a rather short Xmax, so probably won't be too happy running as low as 90Hz (if you want to get to full power at least), sorry. Always to your modelling and research before buying drivers. Thirdly, although WinISD will suggest a large box in order to keep the response flat to as low a frequency as possible, you don't have to stick with that. Assuming you'll use a DSP to give your crossovers, you'll have the option of applying EQ as well, so you would be able to use a much smaller box and then EQ it to be flat enough over the range you're planning. Fourthly, you definitely don't need to worry about staying within hundredths of a dB as referenced in the output you quoted - no-one can hear differences that small. Even experienced listeners in a good environment typically can hear differences of about 1dB, and less experienced listeners in ordinary environments (ie typical punter at a gig) may only start to notice things when the difference approaches 3dB. HTH, David.
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duppy conqueror
Registered User Joined: 21 March 2015 Status: Offline Points: 46 |
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Yes sorry I posted the wrong link. Now it should be right.
This xmax is more. Its 4.4 mm. that would work better right? thank you
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duppy conqueror
Registered User Joined: 21 March 2015 Status: Offline Points: 46 |
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second how much smaller do you think I can go until it really starting to affect the sound?
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bass*en*mass
Old Croc Joined: 03 September 2009 Location: "unknown" Status: Offline Points: 4009 |
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370l def. aint right..
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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OK, so it's the Beta you're using? Your thread title and first line of the post still say Delta. Here's a pair of Beta 12's in 60l tuned to 60 Hz with one high pass filter and one EQ applied. The green curve in the background is a theoretically perfect 24dB Butterworth crossover at 90Hz - so with just the one EQ you can get within 1dB of that. This still only takes a couple of hundred watts to reach 4.4mm excursion, but does allow the pair of drivers to get to around 127dB at that level. Edit - clearer image
Edited by DMorison - 29 May 2017 at 4:30pm |
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DMorison
Old Croc Joined: 14 March 2007 Location: Aberdeen Status: Offline Points: 1649 |
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PS, the filters used were a 74Hz Butt12 HPF and a 135Hz cut of 3.2dB with a Q of 1.3 if you want to re-create the above.
Cheers, David.
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