MTX woofer shoot out video

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http://www.mtxaudio.com/smoked/index.cfm

This is a promo video from MTX. It shows them blowing up a Kicker L-7 and a JL W-7 by applying 100's of volts to the woofer. It shows them putting voltage to the woofers and they smoke at just over 102-106 volts. Now Im confused what or how dose voltage determan if a woofer is strong? When I checked the output of my Sub Amps (Orion XTR-2400's) 1800 watts, They were not putting out anything more than a 0.07 volts on my volt meter, So I dont know how throwing 106 volts at a W-7 or a L-7 shows it's worth or is a real life test.

It seems like everyone is compeating for the W-7s crown of top subwoofer. Everywhere sales people are saying the same thing "Buy this (insert your faverote brand) woofer it sounds as good/better than a W-7" IMO if its stronger and sounds better than a W-7 then its better than a W-7

The MTX 9500 that they are selling is no cheeper than a W-7 and untill I can hear it head to head I call B.S on it sounding better than the W-7, So whats the advantage.

Im for what ever is better. If you can get the same thing for cheeper Ill switch. If you can make a better woofer and it cost's more so be it. I have had breakdown issues with W-7's so I wouldnt mind a alternatieve to the W-7, so thats why I keep my ear to the ground, there is so much hype you can be talked into changing your whole sysytem and have no better results. So dont waste your time saying "Grant try this woofer" this video could be a great example. I have learned. Dont believe the hype. Hearing is proof. If you go to the stereo show's and talk with people. You get a much better Idea what is the truth. IMO shops will try to sell you what ever they make the most money on.

To answer some of my Own questions, The voltage is in direct relation to watts, I talked with the guys at MTX this is how they explaine it

Volts is watts you can detreman watt's via the volts dvided by the reststance

Example. The W-7 poped at 106 volts, You take 106 volts, you Square or times it by 2 it thats 11236 then you devide that # by the resistance of the speaker. The 12 W-7 is 3 Ohm's so you devide it by 3 you will have the ammout of watts. They were pushing 3,745 watts to the W-7 before it blew, BFD
Ok sure I wont push 3000 watts threw my sub NO PROBLEM. How many people have a amp that can push 3000 watts, The MTX 9500 pops at over 5,000 watts.
So I still dont know what that video is realy proving

Actually:

(volts x amps)/impedance =watts

WATT: It is used as a measure of electrical and mechanical power. One watt is the amount of power that is delivered to a component of an electric circuit when a current of 1 ampere flows through the component and a voltage of 1 volt exists across it.

I think it is proving to the hardcore SPL guys that the MTX sub can handle more than the JL. As for who has that much power, the extreme people, like Team Gates, have tens of thousands of watts of power. If I remember, they have 48 individual 1,000 watt amps. In reality, it's jsut proving how cool they are. Think manrod envy.

http://www.teamgates.org/

Will

when it show's 106 volts at the woofer and I know the woofer is 3ohm's thats around 3700 watts correct?????

Basic AC/DC theory supports William's formula. But getting more real life, I would look at the experiment as only what they stated...that it can handle more power the the others.
You could extrapolate that the high power survivor could be more durable, but I'm with Grant. Hearing is believing.
The thing that most often causes failure is excessive Heat! But to make a speaker handle more heat, it is often done by heavier wire in the voice coils and other moving parts.
It's almost a catch 22, heavier wire for durability, but you lose performance as a result of the added weight.
I support the "Listen....then decide" guide.
Get a good warranty and follow the manufacture guidlines so as to not void the warranty.
D out

depending on the amps... We are missing part of this equation... remember the saying, "it's not the volts that will kill you, it's the amps."

we have the volts, but we don't have the amps... so if it is 106 volts at 1 amp, there is only 106 watts... assuming there is at least 40 amps @ 106 volts, you would have about 1413 watts... 2826 watts with 80 amps at 106 volts. It would be nice to know what they are powering it with.



Since we are on the subject... you will notice on most amps they say they were tested at 14.4 volts... which is the max a car charging system will put out (normally in the 13's)... so they are all misleading everyone with their max output rating... just thought I'd get on my soapbox for a second, sorry.

and I second what duane says... some people might prefer a better sound with a little less durability, but others might prefer a lower quality sound for something that might be more durable.

And remember MTX is "MARKETING" a product.

power is volts times amps, Im sure they are testing compareable subs IE: 4 ohm impedence with 4 ohm impedence not sending 100 volts thru one 8 ohm (however you figure it-dual 4 ohm subs coils in series etc) and 100 volts thru a 4 ohm competitor. Their test is still misleading since i dont here anything about spl which is the efficiency that the sub makes noise with the available power it consumes, more efficient sub is louder and less efficient sub requires bigger amp to sound the same. This is all still not taking into account sound quality. Sorry but the ca rvoltage deal (14.4 volts DC) has nothing to do with the AC signal coming out of an audio amp, not sure myself what kind of voltage it is either (maybe i should borrow a scope from work??)

Last time I checked I couldn't hear the volts going through my woofer, I heard the air being displaced (ie SPL). Maybe they should add a measure of air displacement for a given watt. Hmmm, isn't that the efficiency rating... They should provide SPL vs. Watts curves if they really want to prove something.

(Message edited by mikeski on August 16, 2004)

It also sounds like they are just doing a DC test. When was the last time you heard a DC sound? The major factors have to be how is the coupling of the different frequencies into the sub.

Just to start with a little FYI.

OHM'S LAW


V = I x R

(volts x amps)/impedance =watts (from William above)

Look at the formula for Ohm's law. Just for note, Impedance is used when describing a changing resistance to a given frequency, meaning it will not have the same resistance for every frequency. Resistance is used when describing a fixed resistance over a range of frequencies. Mostly used in DC electronics. I guess the accepted DC coil reistance is 3 ohms for the JL Audio.

Frequency Response of a Coil/ resistance value in a coil for a given frequency:

Speaker Impedance = Inductor Value * Frequency *pie*2

When looking at a speaker, it has to handle multiple frequencies. As the frequency goes up, the impedance (resistance goes up). Take that aside and look at OHM'S LAW again.

V = I x R

That tells you that for a given Resistance, the only way to up the current is to up the voltage, because, our formula for a Coil reistance per vs frequency tells us that the reistance is fixed and something has to give. So, current can only be produced by varing the voltage or the resistance. Resistance is fixed per the frequency so voltage goes up in high power amplifiers.

Now, with that being said as a general FYI. Speakers design is not designed by static DC voltage loads as in the MTX test. They have to be designed with certain mechanical and electrical Q's and other variables. It can also be as simple as the type of amps you buy as well. Different amps are designed to drive different types of loads. Just because you buy a big overpriced amp, does not mean it will couple all of it's frequencies into you speaker properly. It may be low enough frequencies in general not to matter too much, but, in AC electonics, you have to frequency match your components inorder to get maximum coupling. If you do not couple, you get back reflections. SO, you may have a high power amp, but, you may only couple as well as a high quality smaller amp.

How could the MTX hold up to a similar test performed at let's say 55 hz. I think that is frequency around the Low E string on a Bass Guitar. Now they would take into consideration the mechanial power handling and response as well. I think the test is a bit misleading.

Rod: Im not sure Mabey Mike can answer this better, He has a Link to Team Gates on his signature so that leeds me to believe he know somthing about SPL,

When they have the sound off compitions to test SPL (Sound Pressure Level) they tune they woofer boxes to produce a 30 hz bass note. I dont know if that was the 30 hz bass note we heard with the MTX video, It was hard to tell because the subs were not in a box.

I think what MTX was trying to show is how there subs could handle Like over 5,000 wats. Do your math see if 146 volts with a 4 ohm load comes out to that? The way it was explained to me it made sence and I understood it. But they way everyone else is explaing it, I might have gotten the short version, or was misinformed, Look at my earlyer post and see is that correct??

dont know where you are getting the formulas for power but it is v X I = P , impedence is already being taken into account when you see the current being consumed in a circuit... That was ohms law and V / R = I or V / I = R or I X R = V

If you have an amp running 13.5 volts and consuming 50 amps it is running 675 watts and NOT 13.5 X 50 / (say a)4 ohm sub= 168 watts
I know im getting better then 168 watts out of an amp sucking 50 amps.

I can not view the video for some reason. My bad, I was assuming they were not hitting it with a test tone but with a DC source. The theory I posted still applies though.

OK... the video just loaded while typing this. That test is totally unrealistic. You can not take a sub in free air and do that. I completely depends on the QTS of the sub. What they are saying to me is a couple of possibilities. One on the mechanical and the other on electrical:

1) the sub has a higher mechanical Q than the rest of the subs and did not break up in a free air application. That being said, I also would believe that the sub would have a higher mechanical resonance than the others and would not mechanically break down and coming out of alignment in a free air application. Another point to be made would be that in the past, JL audio has made their cones heavier and have a longer throw than the other speakers. Matter of fact I think that is why JL audio talks about in their literature on the W7. They say it has a long throw compared to the competition. Look at the JL Audio naturual hi frequency role off numbers. They are never speced above 200 Hz.

2) Voltage does not mean crap. All that means is at the test Frequency, their sub held more voltage. It says absolutely nothing about the current being passed through the other subs. Remember my post above-

V = I x R IF the JL Audio has a lower impedance at the test frequency, it will actually have more current flowing and current is what effects the magnetic field around the woofer voice coil.

I am disappointed that MTX is using such garbage tests. They are trying to put it out there to capture the imagination of people who only see a number and smoke. Put the speakers in a proper factory sealed box designed for a Q=1 and then let them run the test. Then measure the SPL and maybe even a waterfall plot of the damping of the system at given frequencies and we can talk.

On the 4 ohms vs. three ohms, I am not sure where they actually get that from? Anyone know where exactly that number comes from? I think it has to do with the DC measurement of a coil, then of course the resistance goes up as the frequency goes up from near DC. So, none of us would have a way to know what the actual designed/ measured electrical impedance at 30 Hz is for each woofer. That is the number one reason that test means absolutely nothing. They are trying to make it look like it is some sort of horsepower reading and it just does not work that way.

This is kind of referencing Bob's post. I am not an electical engineer, but, just because an amp uses a 14.4v input from a car electrical system, does not mean they are keeping the amp output at 14.4. They can step up the voltage in the amplifier then the current draw is a function of heat handling and what your car can deliver. In order to get the power up, the voltage has to be stepped up. You can not go against Ohms law.

Grant is getting the number of volts of the test video, but, the biggest assumption is that all the amps are at the same impedance at the test frequency. That is very misleading. Then throw in the fact that none of them are in a box? Throw it out the window.....

sorry for all the posts. If you look at Ohm's law again:

JL Audio:

106.1 V /3 ohms = 35.4 amps

MTX

142 V /4 ohms = 35.5 amps.

Then add that into the calculation of power P=IE

JL Audio:

106.1V(35.4 amps)=3755.94 watts

MTX:
142V (35.5 amps)= 5041 watts

NOTE: I am making a HUGE assumption that those are the values for resistance values for each woofer at the test frequency. But, you can see plainly that it can be heavily influenced by just one ohm at the test frequency. Assume that I am dead on about the resistance at the test frequency. Is that saying that that the MTX woofer is less effecient? I mean taking more power to draw the same current? Actually that is misleading too. You need to know the efficiency and sound quality to make a judgement. What if the values are 10 ohms at the test frequency for the MTX?

142v /10 ohms = 14.2Amps

142volts(14.2amps)=2016.4 watts

Like I said a lot of assumed values.....



(Message edited by deltahoosier on August 17, 2004)

Bob... I screwed up the equation (with the ohms--I don't know where I got that, I think I combined the two equations). I got the first one right... "106 volts at 1 amp 106 watts..." hehehehe

But like I said before, and it goes to what Rod said... MTX is Marketing a speaker!!!

Oh yeah, and a question... so if the amps are tested at 14.4 volts, the amp will still put out the same power if your car charging system is only putting out 13.5 volts?

(Message edited by sonicr1 on August 18, 2004)

rod it appears to be around a 5-10Hz signal so not DC

Hey guys,

Thought I would confuse the matter a little.

Grant, your calculations are right. There are many variations of the power equations.

P=E*I (where E is voltage)
also, I=E/R
If you combine these two equations you get:
P=V^2/R and that would give you your 3700 watts. That is the same equation MTX gave you. Anyway, it should be noted that these numbers are instantaneous power values and not RMS. Since music amplifier ouputs are AC (sinusoidal wave), RMS wattage calculations are much more accurate. Most respectable amp and speaker companies will give you the RMS values of their products.

But in this case it really doesn't matter since the test is marketing garbage. MTX simply found a weakness in their competition's products and exploited it. But is it really a weakness? You just can't tell from this test. The only thing you can get from this test is that MTX was able to overheat the other woofers.

Some very important data is missing as most of you already know.

1) the time elapsed for each test
2) woofer impedence
3) signal frequency and waveform. (sine, square etc.)

All this will severely effect the outcome of the testing.

Hoped some of this made sense.

Jlembas
Fluid Concepts
www.fluidconcepts.net

Thanks Tim...I noted the mistake in my second go around.

Rod i was not saying they (car sytems) put out 12-14 volts but just what you said the amp stepps the voltage up. 5-10 hz would be beyond human range (20-20 k hz) , did we all hear the sub?? Fluid concepts your formulas are NOT the same as was posted earlier since yours have an extra symbol between "V and 2", whole different formula then.

OK....wasn't sure. Actually you would most likely not hear even an audiable frequency because the baffle size holding the woofers were not large enough to stop the cancellation of the forward and rearward propegating waves. Still a dishonest test at 5 to 10 Hz. What speaker works there?

The MTX sounds so sweet in that video, why did I ever buy my 10W7...