<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by loudsubz:<BR><STRONG><B>Too Little Power:</B><BR>As you have probably heard, some people say that too little power can blow speakers. Well... How can I say this... BULL S*** <P>Too little power will only cause the maximum output level to be low. Abuse and the defective 'wing nut' (an idiot) connected to the volume control blow speakers with low powered amplifiers. If driving a speaker with low power would cause them to fail, speakers would fail every time you lower the volume on the head unit. I will try to explain what happens when speakers are driven with clipped signals but remember... you get what you pay for. <P><B>Damaging Woofers: </B><BR>When a woofer is driven with a high powered amplifier to high levels, there will be a significant amount of current flowing through the voice coil. Since the voice coil has resistance, there is a voltage drop across the speaker's voice coil (which the amplifier appreciates greatly . This means that there may be a great amount of power being dissipated (in the form of heat) in the voice coil. When a speaker is driven with lots of clean power, the cone moves a great deal (in proportion to the output voltage from the amplifier). For speakers with vented pole pieces, this movement forces a lot of air to flow in the magnetic gap (area where the voice coil rides). When the woofer moves out of the basket, the chamber that's under the dust cap and around the voice coil expands which pulls cool air into the magnetic gap. When the woofer moves the other direction, the chamber size is reduced and the hot air is forced out of the vent in the pole piece. This air flow cools the voice coil. If a relatively low powered amplifier is driven into clipping (to a full square wave for a lot of people), a relatively large portion of the time, the voltage delivered to the voice coil no longer resembles a sine wave as it would with an unclipped signal. While the amplifier's output is clipped, this voltage may be considered to be DC. No matter what you call the clipped part of the waveform (DC, not DC...), the voice coil is not being motivated to move as far as it should for the power that's being delivered to it and therefore is likely not being cooled sufficiently (since the speaker is driven by a linear motor, the voltage applied to the voice coil determines how far the voice coil moves from its point of rest). At points a, b, d, e, f and h the voltage is changing causing the voice coil to move in the gap and therefore pull in fresh cool air. At points c and g, the voice coil may still be moving a little due to momentum but may not be moving enough to cool properly. Remember that during the clipped portion of the waveform current is still flowing through the voice coil. Since the displacement of the voice coil (and therefore the airflow around the voice coil) is no longer proportional to the heat being generated, the voice coil can overheat. This excess heat may cause the voice coil former to be physically distorted or melt the insulation off of the voice coil wire (especially if the speaker is rated to handle no more than the power that the amp can produce cleanly).<P>taken from : <A HREF="http://www.eatel.net/~amptech/elecdisc/2ltlpwr.htm" TARGET=_blank>http://www.eatel.net/~amptech/elecdisc/ ... .htm</A><P>[ March 28, 2002: Message edited by: loudsubz ]</STRONG><HR></BLOCKQUOTE><P><BR>You COULD NOT BE MORE WRONG!<P>DC is a COMPONENT of a clipped signal, however, as long as that dc component is carried by an AC wave, it is literally impossible for the DC to hold the driver at full excursion for a long enough period of time to damage the coil by over heating.<P>20Hz Square wave is still alternating 20 times per second, and if it's moving the woofer peak to peak, that woofer is receiving all the cooling it is designed to need!<P>A woofer doesn't know the difference between square waves and sine waves.....
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Audiophyle:<BR><STRONG><P><BR>You COULD NOT BE MORE WRONG!<P>DC is a COMPONENT of a clipped signal, however, as long as that dc component is carried by an AC wave, it is literally impossible for the DC to hold the driver at full excursion for a long enough period of time to damage the coil by over heating.<P>20Hz Square wave is still alternating 20 times per second, and if it's moving the woofer peak to peak, that woofer is receiving all the cooling it is designed to need!<P>A woofer doesn't know the difference between square waves and sine waves.....</STRONG><HR></BLOCKQUOTE><P>Whoa, settle down there big boy. No need to get your panties in a knot. I just simply posted what was on the site, I neiother agree or disagree with the post, just linking to what another had to say.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by EvilSnot:<BR><STRONG>Careful who you call kid......</STRONG><HR></BLOCKQUOTE><P>Did I just get threatened??? You have to be kidding. <BR>You guys are just repeating information that others have stated. If you look at most user manuals of a subwoofer it will say something like Power R.M.S. 50-300W. Hmm...why would they put a minimum power on there. It's because if you power the subwoofer under that ammount of power, the voice coil will not move fast enuff to cool it from the extreeme heats produced by the electrical current. It has nothing to do with sine waves or "square" waves. If you hooked up a voltometer to your amplifier you will notice that at level 10 on your deck your amp will put out 300W and at 20 it will put out 300W. The voltage will decrease with volume, which will decrease the heat output from the coil. The wattage is what you need to keep constant.<P>Maddbuck, go ahead and power your subs with that amp. The MTX4000 subs shouldn't require more power than that is able to put out. Although like most of those links say, if you want better sound, and larger output you will need to get a bigger amplifier. My cuzin is powering 2 4000 10's with a 4 channel 600W amp (puting about the same wattage to each sub as you will be) We bridged the amp and wired the subs in parallel and it puts out amazing bass. He has it in a ported box, sharing sub space, with 2 2" ports. Your system should be very nice.
~Ryan~
1994 MX-3 GS Teal
Stock V6 with insane potential
1987 Toyota Pickup
SR5 Xtracab Turbo
--The slow wait until the green light, while the FAST already left when the red went out--
--Sex should be like driving a Honda....slow, obscene, and loud enough for the neighbors to hear--
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sonicxtacy02:<BR><STRONG>you guys love this crap a little too much <P>ps. Anyone want some mtx's? </STRONG><HR></BLOCKQUOTE><P>Hey man, what size are your subs?
~Ryan~
1994 MX-3 GS Teal
Stock V6 with insane potential
1987 Toyota Pickup
SR5 Xtracab Turbo
--The slow wait until the green light, while the FAST already left when the red went out--
--Sex should be like driving a Honda....slow, obscene, and loud enough for the neighbors to hear--
Sorry if that sounded like a threat, call it being defensive (somehow being called a "kid" seems like a derogotory comment, but oh well ,lol). <BR> I am going to try to put this as nicely as possible though. <BR> You said that we are repeating information that others have stated. That is true. I am citing information that for the most part I understand from very reliable sources. If you've never heard of Richard Clark or David Novoune, stop reading this right now, because it's only going to make you angry (not understanding who these guys are will make this entirely moot). They aren't infathomable, but I have yet to meet anyone in the industry with the amount of knowledge, experience, or resources.<BR> As far as your theroy of "constant voltage" it's wrong. If you disagree, back it up with something other then your personal opinion. In all honesty, I havent the foggiest what your talking about. If the voltage decresed with volume, so too whould the wattage. Neat little formula, i(v) = p . I know its rather basic, but in a nut shell it says your very very wrong. So i'll make it simple. An ampilfer works by taking a small signal and making it bigger. The signal strength from your deck, for the most part, is irrelevant. <BR> Let me stop right there. Your saying that an amp always produces it's rms power, which is insane. It produces power based on the input signal multiplyed by the gain and the total resistive load. I run a 1200w rms amp. If it always produced 1200w, it whould drain my electrical system and destroy my battery. Why? Because iV=p. Current X Voltage = power. how much current is needed for a 1200w amp to produce 1200w on 12v electrical system? 100amps? Nope, guess again. power is lost in heat & in-effeiency, so roughly 140a @ 12v is required for my class D produce max rms power (not max power mind you). If it always produced that much power, my 60a alt and battery would be drained in a matter of minutes (my summit, not my mazda, lol). <BR> When you turn down the volume, you decrease the total output (it ifs not as loud, its not producing as much power, go figure). <P> But to answer it out right ("It's because if you power the subwoofer under that ammount of power, the voice coil will not move fast enuff to cool it from the extreeme heats produced by the electrical current") :<BR> The cone will move in propotion to the power. Running a stroker off a 75w rms amp will not kill it. Why? Because 75w is 75w of heat, which isnt much to begin with. 75w will also move the woofer enough to dispate 75w of heat. Though I honestly doubt that you could blow a stroker running it off a 75w true dc source as the coils thermal ratting (that's why i said a coil is basically a fuse!) isn't enough to melt it. That post is grossy misguided, and I present you the same question you posed to me : where did you get your information? I showed where I acquired some of mine that actually applies. How bout just one source to back up yours? <BR> <BR> In closing, let me say this: An amplier is a transformer, it produces AC current from a DC source. It takes both amperage (current) and voltage to prduce wattage. Neither the current or the voltage matter for the creation of power (If I have 12v and 100a, its 1200w, if I have 6v and 200a it's 1200w and so on and so on and so on.) Your really, really, really off on that last one, please, for the sake of people that acutally read these posts, just skim over my links and then come back here and tell me im wrong (with some sort of anything to reference it).
<P><B>Damaging Woofers: </B><BR>When a woofer is driven with a high powered amplifier to high levels, there will be a significant amount of current flowing through the voice coil. Since the voice coil has resistance, there is a voltage drop across the speaker's voice coil (which the amplifier appreciates greatly 
You have to be kidding. <BR>You guys are just repeating information that others have stated. If you look at most user manuals of a subwoofer it will say something like Power R.M.S. 50-300W. Hmm...why would they put a minimum power on there. It's because if you power the subwoofer under that ammount of power, the voice coil will not move fast enuff to cool it from the extreeme heats produced by the electrical current. It has nothing to do with sine waves or "square" waves. If you hooked up a voltometer to your amplifier you will notice that at level 10 on your deck your amp will put out 300W and at 20 it will put out 300W. The voltage will decrease with volume, which will decrease the heat output from the coil. The wattage is what you need to keep constant.<P>Maddbuck, go ahead and power your subs with that amp. The MTX4000 subs shouldn't require more power than that is able to put out. Although like most of those links say, if you want better sound, and larger output you will need to get a bigger amplifier. My cuzin is powering 2 4000 10's with a 4 channel 600W amp (puting about the same wattage to each sub as you will be) We bridged the amp and wired the subs in parallel and it puts out amazing bass. He has it in a ported box, sharing sub space, with 2 2" ports. Your system should be very nice.
