rough figure for db's of my setup

I have a 94 gmc sierra ext. cab and I am thinking of running 4- 10 inch MTX 8000's single voice coils wired in a 2 ohm load and pushed by kicker kx800.2 amp, was wandering of about or any idea of the db's that might come out of this?live in your world, come play in mine

any where from 0-135 would be a rough figure    Its impossible to give you a close estimate.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

Ditto to the "impossible to tell" comment from Alpine Guy.  But before you hook up your system and start trying to hit ANY db number, realize a couple of things: That Kicker amp cannot be bridged into a single 2-ohm load.  It is only capable of sustaining a 4-ohm load when bridged.  Also, the SVC MTX 8000 series is a 4-ohm speaker, so you cannot connect 4 of them togehter to achieve a 2-ohm net load.Support the12volt.com

Actually, guys, it IS possible to tell a rough estimate of how loud he will get. 1: Take the efficiency specification of the driver in dB/1w/1m. Call that number X 2: Add 6 (because there are 4 drivers) X+6=Y 3: Starting with 4 (1 watt per driver) count how many steps it takes to get to 400 (which AFAICT is the 4 ohm bridged power of this amp) Call that number N 4: Take that number, multiply by 3 N*3=Z 5: Add that number (Z) to Y Example: X=90 X+6=Y=96 4,8,16,32,64,128,256 (The remaining 128 watts available from the amp will add about 1.5 dB) 7 doublings * 3dB per doubling = Z = 21dB additional output. 96+21=117 dB, give or take a couple. Alpine Guy, you ARE correct, it IS between 0 and 135dB, but I think shane7643701 was looking for something a little closer... I just wanted to show that it is possible, given at a minimum, the number of drivers, the amplifier power, and the efficiency of the driver, you CAN indeed get an estimate of the system output. I do want to mention, though, these ARE anechoic numbers, and the cabin gain (and cabin gain IS dependent on the cabin, obviously) can add as much as 12dB at various frequencies, but NOT across the board.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Ok, here is the problem with your formula. First, it is correct for home audio where you are dealing with sound waves, but in cars you deal with sound pressure (notice why soundoffs are called SPL not DBL), but since you know the formulas you should know this already. Out in the open or in a warehouse these formulas would probably work rather well to get an estimate. Also, we have no idea what kind of box he has the subs in, which will affect the sensitivity of the sub greatly (remember that sensitivity is done in a warehouse, free air, with a mic that is 1 meter away with 1 watt of power). The sensitivity of the sub is a rather useless number unless you are going for sq+. This is just my 2 cents from experience.Certified Security Specialist

Always check info with a digital multimeter.

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ALL SPEAKERS MAKE SOUND WAVES. Sound in measured in SPL WHEREVER you measure it. Yes you DO deal with sound pressure, but in the home (or warehouse or wherever) you also deal with sound pressure, WHEN THE WAVELENGTH IS LONGER THAN THE ROOM... it is still sound! (I think you are getting confused between sound and sound pressure... they ARE the same thing) The same rule applies in the car, this is called room (or, in the car, CABIN gain). The numbers above, are (yes, I admit, I should have specified the TYPE of enclosure) for a sealed enclosure. Add 3 dB for a vented enclosure, or 6dB for a bandpass enclosure, but also remember that when you vent a small (required for automotive use, because of the physical limitations of the CAR) you will sacrifice low frequency extension for output. Ya canno' change the laws o' physics! You will also notice that I did refer to cabin gain, and I also mentioned that cabin gain is not a uniform boost across the spectrum. It will be based on the HARMONICS of the cabin. Smaller cabins, such as trucks, will enhance higher frequencies, and larger cabins, such as an Explorer or the like, will enhance lower frequencies. Also, most manufacturers base their sensitivity ratings on the Theil-Small parameters of the driver (mathematically derived, based on MMS, BL, and other parameters that are relatively fixed values), they do not put the driver in a box, and test it - they can't, because of the tens of thousands of drivers they make, and I can tell you this is true, because I have measured literally hundreds of drivers, and VERY few ended up being right on the mfr. spec. for efficiency. It actually comes closer to an infinite baffle sensitivity, also. The spec will change, based on the tolerances allowed in the manufacturing process, usually + or - 10 percent. More expensive drivers will usually use higher tolerance parts, and therefore come closer to mfr spec. I really am curious, what makes you believe that a woofer does something different in an automotive environment than in a home environment? All loudspeakers, from tweeters to woofers, to full range drivers, are electromechanical devices that do nothing more than excite air molecules in a compression/rarifaction pattern, based on the frequency being reproduced. It does not matter where it is measured, as long as you allow for room gain. You will get the output of the driver. The space (distance) between the wave (the outward movement of the cone - high pressure) and the trough (the inward movement of the cone - low pressure) is called the wavelength, and it is the same in a car as it is in a non-moving rigidly placed building. The room (or cabin - interchangeable, both verbally and physically) has an effect on SOME of the frequencies more than it does on others. These are called standing waves, and you can figure these as well, AND say how much the gain will be at a given frequency, as well as the harmonics of that peak frequency, with relative precision.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Oh, and efficiency has NOTHING to do with whether a driver will be an SQ driver or a high output (I do not want to say SPL) driver in a perticular application. I have seen extremely inefficient driver simply BLAST with enough power, and I have seen very efficient drivers sound simply PHENOMENAL. I have also seen extremely inefficient drivers sound like CRAP, and very efficient drivers not play as loud as one would expect, because they cannot handle any power to speak of. Play around with Tractrix horns and transmission-line enclosures, before you say something like "efficiency is a useless number except for SQ drivers"... Sorry for the tone... sometimes I get a little passionate about my audio, AND my actual schooling in the audio world, as well as my years of hands-on experience. I admit I do not know everything, but I am quite knowledgeable in what I do know, and I am always looking to learn more. I do know that if Steven Kephart is reading any of these posts, he will correct me, and I hope that he does.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

cabin gain...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."