posted                          

quote:

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Originally posted by petyolite:
i have a moded mmats 2200 running 1/2ohm mono on 2 12" soundstream devinci subs. my ? is if they are mono why is one getting alot hotter then the other

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They got too hot because the amplifier saw 1/2 ohm mono.
the term Watt is a term used to describe HEAT DISSIPATION, and at a 1/2 oh the amplifier was being cooked, not just the voice coil on the subs.
OH, one more thing, NO AMPLIFIER manufacturer "LIKES" to run their amplifiers hot(or thermal), just because specs say that an amp put out X amount of power into a short circuit, doesn't mean you should do it. Car amplifiers are ALL designed to run at 4ohms, no exceptions.
if you reduce the resistance you will increase power, distortion, and lose control of the woofer, and quality of sound, and longevity of your system (never mind the vehicle's electrical system), or your warranty, which does not cover "abuse".
If you need more power, buy a bigger amp that will give it to you properly, don't try to squezze the lemon.

--------------------

E.C. Wuz here

Posts: 1057 | From: Vancouver, British Columbia, Canada 'eh | Registered: May 1999  |  IP: Logged | 

posted                       

quote:

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Originally posted by Eli47:

quote:

---

Originally posted by petyolite:
i have a moded mmats 2200 running 1/2ohm mono on 2 12" soundstream devinci subs. my ? is if they are mono why is one getting alot hotter then the other

---

They got too hot because the amplifier saw 1/2 ohm mono.
the term Watt is a term used to describe HEAT DISSIPATION, and at a 1/2 oh the amplifier was being cooked, not just the voice coil on the subs.
OH, one more thing, NO AMPLIFIER manufacturer "LIKES" to run their amplifiers hot(or thermal), just because specs say that an amp put out X amount of power into a short circuit, doesn't mean you should do it. Car amplifiers are ALL designed to run at 4ohms, no exceptions.
if you reduce the resistance you will increase power, distortion, and lose control of the woofer, and quality of sound, and longevity of your system (never mind the vehicle's electrical system), or your warranty, which does not cover "abuse".
If you need more power, buy a bigger amp that will give it to you properly, don't try to squezze the lemon.

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thats like saying "dont turn it on and it wont get hot"

looking at the pics the subs are in common chamber and both are equal distance from the port and both running of the same mono amp so i dont see why one should get hotter than the other
...you got me

--------------------
glenn smeby
TEAM KRYPTONITE
TEAM THUNDERFORCE-2003

Posts: 1655 | From: panama city ,fla. | Registered: Jul 2001  |  IP: Logged | 

posted                          

quote:

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Originally posted by petyolite:
If all amps are made to run at four ohms why do they make them bridgable...why do companies modify amps and why do they include a lower ohm load on the spec sheet?.....because the amps are designed to run at a lower ohm load....yes I compete with my amp that's why I had it modified, I did a power test on my amp and at full power I was getting 2300 watts burping it, my subs are rated at 1000 watts a piece so in day to day use I don't think I exceeded 1000 watts each....and I don't run it hard in my day to day use and when I do use it everyday the amp doesn't get hot only the subs...like I said in previous post I had just finished competiton and a friend borrowed my car and he played it long and hard while all my adjustments were turned up...and my automotive electric system is just fine...I've got a modified alternator, an extra battery and 4 guage wire run through out

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I've been trying to answer this for some time, but always got interrupted.
Yes, all 12Volt units are designed to operate at a 4 ohm load, amplifiers that are bridgeable are made so that a user can sum the TOTAL power at 4 ohms into one channel, specifically for subwoofer application where the demands of stereo are not required, because we percieve low bass as mono. Note that when ANY amplifier is bridged, although the power is increased, so does THD and especially the most damaging TIM distortion levels are increased by more than double, and the amplifier reacts to HALF the load presented to it, because only half of each channel is used.
Manufacturers do indeed improve on models year by year, they do this because they get so many burnt units that they are trying to improve on designs in order to reduce their rate of failure(most often due to abuse).
Specification sheets are also provided to show what the unit will do at specific points in impedance and power, keeping in mind that when any unit (amp etc..)is tested, it is tested to IHF or DIN standards. That is to say that the amplifier in question is connected to a 4 ohm resistor, not a reactive load like a speaker(whose impedance changes with the movement of the voice coil position in the magnet gap), then a sine wave (test tone) is passed through (typically 1KHz) and the output is measured.
I don't listen to resistors, and I don't listen to a single 1KHz note in my music. Music being a far more complex signal because amplitutde and frequency changes, plus the speaker sends a return signal(Motional FeedBack)which the amplifier must ignore (see Damping factor).
Soemthing no spec sheet can show. So you'll find most knowledgeable audiophiles will ignore specification sheets, because we don't listen to paper.
Back to wattage, if a lightbulb is only 100 watts, why can't you hold it while it's lit for a long time without burning your fingers? how much hotter is 1000 watts ? is it the same watts for a lightbulb as for your speaker?
Can you see why it burnt now?

--------------------

E.C. Wuz here

Posts: 1057 | From: Vancouver, British Columbia, Canada 'eh | Registered: May 1999  |  IP: Logged | 

posted                       

quote:

---

Originally posted by Eli47:

quote:

---

Originally posted by petyolite:
If all amps are made to run at four ohms why do they make them bridgable...why do companies modify amps and why do they include a lower ohm load on the spec sheet?.....because the amps are designed to run at a lower ohm load....yes I compete with my amp that's why I had it modified, I did a power test on my amp and at full power I was getting 2300 watts burping it, my subs are rated at 1000 watts a piece so in day to day use I don't think I exceeded 1000 watts each....and I don't run it hard in my day to day use and when I do use it everyday the amp doesn't get hot only the subs...like I said in previous post I had just finished competiton and a friend borrowed my car and he played it long and hard while all my adjustments were turned up...and my automotive electric system is just fine...I've got a modified alternator, an extra battery and 4 guage wire run through out

---

I've been trying to answer this for some time, but always got interrupted.
Yes, all 12Volt units are designed to operate at a 4 ohm load, amplifiers that are bridgeable are made so that a user can sum the TOTAL power at 4 ohms into one channel, specifically for subwoofer application where the demands of stereo are not required, because we percieve low bass as mono. Note that when ANY amplifier is bridged, although the power is increased, so does THD and especially the most damaging TIM distortion levels are increased by more than double, and the amplifier reacts to HALF the load presented to it, because only half of each channel is used.
Manufacturers do indeed improve on models year by year, they do this because they get so many burnt units that they are trying to improve on designs in order to reduce their rate of failure(most often due to abuse).
Specification sheets are also provided to show what the unit will do at specific points in impedance and power, keeping in mind that when any unit (amp etc..)is tested, it is tested to IHF or DIN standards. That is to say that the amplifier in question is connected to a 4 ohm resistor, not a reactive load like a speaker(whose impedance changes with the movement of the voice coil position in the magnet gap), then a sine wave (test tone) is passed through (typically 1KHz) and the output is measured.
I don't listen to resistors, and I don't listen to a single 1KHz note in my music. Music being a far more complex signal because amplitutde and frequency changes, plus the speaker sends a return signal(Motional FeedBack)which the amplifier must ignore (see Damping factor).
Soemthing no spec sheet can show. So you'll find most knowledgeable audiophiles will ignore specification sheets, because we don't listen to paper.
Back to wattage, if a lightbulb is only 100 watts, why can't you hold it while it's lit for a long time without burning your fingers? how much hotter is 1000 watts ? is it the same watts for a lightbulb as for your speaker?
Can you see why it burnt now?

---

that is a very very good point and makes lots of sence but it still dont answer the question.....why does one sub get alot hotter than the other one? both subs in the same box running mono on 1 amp

--------------------
glenn smeby
TEAM KRYPTONITE
TEAM THUNDERFORCE-2003

Posts: 1655 | From: panama city ,fla. | Registered: Jul 2001  |  IP: Logged |