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most important specs to decide on subs?


jwatson364

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-3dB point,a great 12-80Hz rating is worthless if the sub starts to roll of above 30Hz and the -3dB point is at 40Hz. A great sub will be linear down to at least 20Hz and is capable of high clean output @ 20Hz. Here displacement comes into play,there is no replacement for displacement(be it driver,port and/or other loading to increase output).

A reference class sub will be capable to below 16hz at levels of over 100dB measured GP two meters from the sub.In room this translates into much higher output as room gain is inevitable.The best subs today can best 110dB measured GP ~1 meter from the sub,at frequencies below 20Hz! This will be over 120dB in room!

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For what it's worth, the power rating of the amplifier tells you how good of a heater the subwoofer is. 10,000W into an 80dB driver is the same SPL as 10W into a 110dB driver. PWK was very adament about this and has written some very funny articles on the topic...which I don't have readily available at the moment.

So what really matters is the max SPL of the subwoofer. You'll be shaking the walls with anything that digs below 30Hz, but will probably want to aim for 20Hz Distortion doesn't matter all too much for shaking walls, but if you want it to sound good I would look for something with less than 5% THD at the max SPL you'll be listening at...

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Bottom line a great sub is defined byclean output,plenty of clean output sustained at high SPL and capable of sustaining(linearity)this output down to below audibility.

Pro subs roll off as fast as falling rocks under 30Hz this is NOT acceptable today. WIth the advent of high displacement drivers there is no excuse to propose subs with poor extension.High outut yYES,but extension down to below 20Hz while maintaining the HIGH output and low distortion MUCH BETTER.

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There really isn't a good spec to look at or trust that will tell you one sw is better than another. Mfgr's often fudge FR response (using -10db), amplifier power (peak burst at 1khz in some bizarre test condition), max spl ( measured at 70hz[:P]), etc. The way I would do it if I bought commercial sw's would be to educatedly guess the displacement capabilities and efficiencies of the sw. Look at the cone area (driver size, multiple drivers), enclosure size, type of enclosure (a ported one needs to be large), amplifier power. The bigger, or more of each of these the better in general. Also look for 3rd party testing and lastly reviews by credible sources with experience with many sw's.

Mike is correct about the amplifier power spec not being a good way to compare sw's. You may have one sw that is a very compact, expensive 12" sealed type that has a 1250w amp (Velodyne) and another that is much larger, cheaper, ported 15" with only a 350w amp ( Epik). In this case the 15" is going to be much more powerful and extended than the small 12" due to much better efficiency from a bigger cabinet, porting and more cone area. This is not to say that the small 12 is a bad sub, it is just a much more specialized design. You have to make sure you are comparing apples to apples.

Arthur,

Many pro subs dream of having true 30hz extension. Many of them are already rolling off heavily at 40hz and even 50hz for some of the real turds. That's the good ones like DSL & EAW that will rock the venue all the way down to 30!

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Can subs dream? [:D]

I doubt they can, can subs move air. They sure do. Some people are impressed by the output of pro subs. Pretty much all pro subs are optimised for maximum clean output,not extension. They should be called GIANT bass modules that pound the pavement and render a few drunk concert goers more hearing impraired. LOL

With the fragile(as in castle of cards) economy we may see a new market segment form ...from consumer gear to Pro gear to POS gear. [:o] BlueRay will mutate into Bad Ray offering a blazing 320-200 resolution in Mpeg 1. LOL

next...

Wol-Mrt changes their slogan to We Crush Prices and ... more!

...further down the road...I finally become low key and humble(aint gonna happen)

The tenth planet passes near Earth in 2012 and there is a major pole shift! We need to reverse the polarity... LOL End of 2012 TheEAR capitulates and signs the Deaf Sub act ...giving the aliens (illegal or outter space?) total power of the sub bass market segment!!!

[:$]

The judgement day arrives!!! TheLord Subwooferus descends on planet Earth from Nirbu (whet ever it is called) and declares TheEAR the supreme master of TheEARTH ...hey see the TheEAR TheEAR..TH.

I seize Hurd's TC Sounds and Ricci's RE XXX's drivers. Then I retire...I also claim Jay's PMS-5400 as my own!!!

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Ricci,

I will then have to keep you in a freezer for 48 Hours. Then defrost the things grasping to the RE XXX's ! Then again you have four RE 18's,you can only manage to hold on to one. [:P]

For some recreational WWE style debates please visit the BS forum, where my best buddy NO Valve and I are in full Christmas spirit !!! [:|]

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Ricci,

I will then have to keep you in a freezer for 48 Hours. Then defrost the things grasping to the RE XXX's ! Then again you have four RE 18's,you can only manage to hold on to one. Stick out tongue

Pfft. I am mutant with chimpanzee like opposeable thumbed feet. I can hold one on each limb. The ported one has retinal scan, voice and fingerprint identity verification system. To deter unauthorized sub jackers.[Y]

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Of a single LMS-5400...not much. I have four LMS-Ultra and will add four to eight LMS-Ultra in a few months. [:P]

I am slightly jealous of four RE XXX drivers...just enough to want my own quartet.[:D]

Jay,

I would not be pulling on the driver,I would pull the trigger. [:@] Plulling the trigger on a four unit purchase of course.

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