this cant be right......can it?

[sinosic 10+ year member]

this is an email i sent and the reply back.....

email i sent....

whats up? im the person eli is having install 4 15" bramahs in his 94 s-10 blazer. how do you get a amp thats rated at 2000 watts rms @ 2ohm to putout 4000 watts @ 2ohms. this mcd4k amp is cea

compliant. 1000 watts rms @ 4ohm, 2000 watts rms @ 2ohm, and 4000 watts @ 1ohm.

reply...

If you set the gains properly, you'll get full output at several impedance loads.

Those ratings are based on the same input, say 1v. So say you get 1kwrms at 4ohm with 1v input. As long as your amp has the headroom, which in your case it does, if you double the input to say, 2v your output will double as well. This can continue until the headroom of the amp is consumed.. In this case, 4kwrms... Or if you run out of current to feed it... or if your subs max out.. factors that will 'limit' the system.

Click to read more...

 

[squeak9798 5,000+ posts]

No, whoever sent you that reply is an idiot.

And you can tell them I said that.

 

[Safe-N-Sound215 10+ year member]

x2. He's either really confused, or blowing smoke up your ***.

 

[xtremebassjunky 10+ year member]

lmao.

 

[DBfan187 5,000+ posts]

Who is the recipient ? lol

 

[sinosic 10+ year member]

anyone ever own a jl audio slash amp? i hear they put out 1000 watts at 1/2/3/4 ohm loads. could this be what he is talking about?

 

[T3mpest 10+ year member]

anyone ever own a jl audio slash amp? i hear they put out 1000 watts at 1/2/3/4 ohm loads. could this be what he is talking about?

that feature has nothing to do with what he's pretending to talk about....

 

[kmanian 5,000+ posts]

squeak I am sorry to disagree with your wisdom but it seems that there is some confusion, what I think the recipient is speaking about is the output voltage, and he is correct in the sence that if your gain is increased under a sprcific load (2 ohms) the voltage on the output side is also increased. this measurement can be converted to watts. If you dont beleave this get out your multimeter and check it out. Now I do reserve the right to say that soundquality will be effected, but it works

 

[T3mpest 10+ year member]

squeak I am sorry to disagree with your wisdom but it seems that there is some confusion, what I think the recipient is speaking about is the output voltage, and he is correct in the sence that if your gain is increased under a sprcific load (2 ohms) the voltage on the output side is also increased. this measurement can be converted to watts. If you dont beleave this get out your multimeter and check it out. Now I do reserve the right to say that soundquality will be effected, but it works

yeah, but your referring to a constant impedence. The original poster as I understand him, is saying that 57 volts at any impedence is 812 watts. His first sentence says, "if you set gains properly you get full output at sevreal impedence loads". Only way to believe that is to believe that voltage is directly porportational to wattage, with no inverse correlation to impedence.

 

[sinosic 10+ year member]

squeak I am sorry to disagree with your wisdom but it seems that there is some confusion, what I think the recipient is speaking about is the output voltage, and he is correct in the sence that if your gain is increased under a sprcific load (2 ohms) the voltage on the output side is also increased. this measurement can be converted to watts. If you dont beleave this get out your multimeter and check it out. Now I do reserve the right to say that soundquality will be effected, but it works

that makes sence, but why would someone want to try to get 4000 watts @ 2 ohm vs 4000 watts rms @ 1 ohm load. the amp is rated to put out 4000 watts rms @ 1ohm load but 2000 watts rms @ 2ohm load.

 

[kmanian 5,000+ posts]

T3 I agree, I also think he is misguided, but in theory it works.

Sinosic in the real world even if you could do this I doubt you would get any audible difference, the most you wuld reolize is 3db, and anything less than that you really cant quanitify on the street. and if you are building an spl system do your self a favor and do it properly.

 

[squeak9798 5,000+ posts]

squeak I am sorry to disagree with your wisdom but it seems that there is some confusion, what I think the recipient is speaking about is the output voltage, and he is correct in the sence that if your gain is increased under a sprcific load (2 ohms) the voltage on the output side is also increased. this measurement can be converted to watts. If you dont beleave this get out your multimeter and check it out. Now I do reserve the right to say that soundquality will be effected, but it works

I fully understand the relationship between gain, output voltage and input voltage.

From what I'm reading of his statement, he's saying that you can obtain the amplifier's maximum output power (in this case, 4kw) with any load by simply increasing the input voltage....which is simply not true. Even at 100% full-on squarewave clipping you'd only get 2kw out of that amplifier into a 4ohm load. Think about that, then go back and reread his message, specifically;

"So say you get 1kwrms at 4ohm with 1v input [...] if you double the input to say, 2v your output will double as well. This can continue until the headroom of the amp is consumed.. In this case, 4kwrms..."

Horse shit, I say. You can not get 4kw out of that amplifier with a 4ohm load, as he apparently states.

Also, since were are still on the topic;

"Those ratings are based on the same input, say 1v."

The opening sentence demonstrates his complete lack of knowledge on the subject. The entire point of the GAIN is to allow full power output with differing levels of input voltage. Ratings are not based on a "certain" input voltage (1v), they are based on the input voltage being anywhere within the range of the input sensitivity (gain) adjustment range..... .2V to 6V, for example.

 

[sinosic 10+ year member]

T3 I agree, I also think he is misguided, but in theory it works.

Sinosic in the real world even if you could do this I doubt you would get any audible difference, the most you wuld reolize is 3db, and anything less than that you really cant quanitify on the street. and if you are building an spl system do your self a favor and do it properly.

this build is going to represent my skills and knowledge so im deffently going to do it right. thats why im researching this. but my question now is why would someone try to get 4000 watts @ 2ohm when the amp is rated at 4000 watts rms @ 1 ohm. the only thing i can think of is if the subs could not be wired down to 1 ohm, and 4000 watts is needed to power the subs. but this doesnt apply to my situation cause the subs have not even been ordered yet.

 

[kmanian 5,000+ posts]

Squeak, I totally agree with you, I must not be communicating my thoughts very well. I was simply trying to get into his mind. He obviously has some knowledge, but just enough to make an *** out of himself. Basically he is using the gain as a volume knob.

Sinosic, If you haven't ordred the subs yet run them at 1 ohm, but also be advised that usually THD increases as the OHMs drop.

 

[squeak9798 5,000+ posts]

I must not be communicating my thoughts very well.

About as well as the person who replied to the OP's email //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif//content.invisioncic.com/y282845/emoticons/moon.gif.9d317aec3339ffe7fde0638df52c628a.gif

but also be advised that usually THD increases as the OHMs drop.

Still inaudible.

Rated power is typically rated at 1% THD for all impedances.....so even at lower loads distortion should not be an issue assuming the amplifier is reasonably well designed.