real peak power of the 1200.1 jbl

[Wonderbread 5,000+ posts]

http://www.eatel.net/~amptech/elecdisc/voltages.htm

read htrough that. Perry Babin has been extremely active in Car audio for YEARS, and is a widely respected source... one proven test is worth a thousand opinions and theories.

copied and pasted - The RMS voltage of a pure‡ sine wave is approximately .707*peak voltage.

‡If the waveform isn't a pure sine wave (like a square wave or a signal with mixed sine waves of different frequencies or music), multiplying the peak times .707 will not give an accurate RMS value and therefore will not give an accurate indication of the work that the waveform can produce when driving a load.

"The peak power is mathematically twice the RMS power output. "

 

[marauder 10+ year member]

Originally posted by Wonderbread http://www.eatel.net/~amptech/elecdisc/voltages.htm

 

read htrough that. Perry Babin has been extremely active in Car audio for YEARS, and is a widely respected source... one proven test is worth a thousand opinions and theories.

 

copied and pasted - The RMS voltage of a pure‡ sine wave is approximately .707*peak voltage.

‡If the waveform isn't a pure sine wave (like a square wave or a signal with mixed sine waves of different frequencies or music), multiplying the peak times .707 will not give an accurate RMS value and therefore will not give an accurate indication of the work that the waveform can produce when driving a load.

"The peak power is mathematically twice the RMS power output. "

AHA! i commend you on your find but you are misinterpreting the information on that site and the author has misquoted some pertinent information. the RMS value of an AC current is .707 of the peak value. the peak value is one half of the peak to peak value. i believe that is what he is saying about the ability to drive speakers but he is not truly understanding the AC principle that we are dealing with. also he mentiones a mixed signal much like you did but here is the truth of it. there is not a mixed signal in audio spectrum. the signal that our amps are multiplying is that of sound. there are different intensities and even different waveforms of this signal but it's the same it's sound. the amp takes this sound converts it to an AC sine wave. the sinewave is then fed into the semiconductors (the transistors) multiplied, and then sent to the speakers to be converted back into the sound that you and I can understand. he's also used the wrong formula to derive wattage. to determine wattage you multiply volts times amps. he's using the formula p=E^2/R. that unfortunately won't give you the correct wattage rating. that does give you the reactance of the electrical circuit that it's traveling through but not a good indication of amp potential.

but on a final note i'll take one of my AC principles books to work tomorrow and scan the pages on RMS for you to look at. after that if you aren't convinced that you are incorrect then i will no longer bother you and allow you to believe what you want to believe.

also as he said that mixed signals won't produce a true RMS value. what he should have said is more like this. with mixed intensities of the AC voltage won't give you a true RMS value which is true. you would have to take an average of the RMS values of the different tones and then take the sum of these values to determine the RMS power output. not double it. the only good that could come from doubling your RMS power ratings is it would give you some bragging leverage and that's it. as far as the electrical principle it's a farce.

thanks

 

[jlaine 10+ year member]

Originally posted by marauder AHA! i commend you on your find but you are misinterpreting the information on that site and the author has misquoted some pertinent information. the RMS value of an AC current is .707 of the peak value. the peak value is one half of the peak to peak value. i believe that is what he is saying about the ability to drive speakers but he is not truly understanding the AC principle that we are dealing with. also he mentiones a mixed signal much like you did but here is the truth of it. there is not a mixed signal in audio spectrum. the signal that our amps are multiplying is that of sound. there are different intensities and even different waveforms of this signal but it's the same it's sound. the amp takes this sound converts it to an AC sine wave. the sinewave is then fed into the semiconductors (the transistors) multiplied, and then sent to the speakers to be converted back into the sound that you and I can understand. he's also used the wrong formula to derive wattage. to determine wattage you multiply volts times amps. he's using the formula p=E^2/R. that unfortunately won't give you the correct wattage rating. that does give you the reactance of the electrical circuit that it's traveling through but not a good indication of amp potential.

 

but on a final note i'll take one of my AC principles books to work tomorrow and scan the pages on RMS for you to look at. after that if you aren't convinced that you are incorrect then i will no longer bother you and allow you to believe what you want to believe.

 

also as he said that mixed signals won't produce a true RMS value. what he should have said is more like this. with mixed intensities of the AC voltage won't give you a true RMS value which is true. you would have to take an average of the RMS values of the different tones and then take the sum of these values to determine the RMS power output. not double it. the only good that could come from doubling your RMS power ratings is it would give you some bragging leverage and that's it. as far as the electrical principle it's a farce.

 

 

thanks

Grasping at straws lately? It seems like you are trying to make something simple sound complex, but honestly... I think you are typing to enjoy yourself...

E^2/R has been used for years, and is quite firm, go back and cross-analyize it with ohms law.

Unfortunately for you, that DOES give the correct wattage value, on both resistive and inductive loads, provided you know what the load of the inductive circuit is at the frequency being used.

Where did you get this crap about the amp taking 'sound' and converting it to an AC sine wave? Have you ever put an oscilliscope on anything?

Put it on a pair of driven RCA's off a head unit once... What do you see?

Ahh... voltage... What do you see on the other side of the amp? Higher voltage...

Use channel A for the inputs off the RCA, use channel B for the outputs off the amp... What do you get? The exact same waveform, amplified...

It goes IN as electrical inpulses, passes through the amplifier stage, and is out... AMPLIFIED. It goes out as it went in, plus headroom.

Why is the assumed peak power more than with a pure sine wave?

We aren't talking RMS sine waves.

 

[marauder 10+ year member]

i grasp at no straws it's just that i understand at an eletrical standpoint how these things work. and as for converting the sound into an electrical wave and back is what happens in an amp.

ok i'm odviously way over everyone's head here so i'll stop with that. PEP is not and never will be double the RMS value no matter what application it's being used in. and as for the e^2/r it leavs out an important factor the original current. it's telling you the electrical potential of the circuit not what your amp is pushing.

look i'm sorry to burst your bubble but it's impossible for the peak power of an amp to be more than the wattage times 1.414. and the real RMS wattage of an amp can never be more than the voltage times the amperage being drawn from it's power source.

thanks

 

[ngsm13 5,000+ posts]

****, this is looking pretty heated thus far. BUT, the original question...the 1200.1 will put out a little in excess of 1200 watts RMS @2ohms and @1ohm. PEAK means NOTHING!!! it is useless in the world of car audio. If it were useful...every1 would buy legacy amplifiers! lol that would be a nightmare. peace

NG

 

[jlaine 10+ year member]

Originally posted by marauder i grasp at no straws it's just that i understand at an eletrical standpoint how these things work. and as for converting the sound into an electrical wave and back is what happens in an amp.

Yes, and I've taken basic analog electronics nearly 10 years ago, and I still know you are grasping at straws.

In fact, with what you've just said there, you know absolutely nothing about amplifier topology or electronics in general I'd say. Converting sound into an electrical wave happens in an amp? Are you daft? How the hell do you even get "sound" into an amp? Sound is excited air molecules, where is the AIR INLET on an amplifier?

I've designed and built amplifiers in my lifetime, have you?

Originally posted by marauder ok i'm odviously way over everyone's head here so i'll stop with that. PEP is not and never will be double the RMS value no matter what application it's being used in. and as for the e^2/r it leavs out an important factor the original current. it's telling you the electrical potential of the circuit not what your amp is pushing.

Hello... First lets try to get away from "pushing" things, I hate that generic highschooler term.

Ohms law, BREAK IT DOWN. E = I*R

You have VOLTAGE and you have RESISTANCE. CURRENT IS AUTOMATICALLY THERE.

Can it be any clearer?

Here.. I'll help..

CURRENT (I) = VOLTAGE divided by RESISTANCE

Why do we measure VOLTAGE?

Answer is elementary. Current measuring devices operate on a magnetically induced field and don't react fast enough under most cases.

It is measuring an ACTIVE circuit. You have VOLTAGE, you have RESISTANCE, and (this is the hard part for you, but follow me here...) you have a VOLTAGE source! Amplifiers are VOLTAGE sources, NOT current sources. Current is passed based on the electrical pressure created by the circuit.

Hi... I am a watt.

I am measured by:

P= IxE

P= E^2/R

A little common math...

P = I x E

I = E/R

THEREFORE

P = E/R x E

THEREFORE

P = E^2/R

Did you grab all of that and hold it tight, it's right there, common algebra!

Originally posted by marauder look i'm sorry to burst your bubble but it's impossible for the peak power of an amp to be more than the wattage times 1.414. and the real RMS wattage of an amp can never be more than the voltage times the amperage being drawn from it's power source.

 

thanks

I assure you, you have NOT burst my bubble.

Have you never heard of burst ratings?

Here is a really dumbed down example:

Why can a battery charger be rated for 250A for 4 seconds, when it's standard duty cycle is for 40A at 100%?

 

[phazeone 10+ year member]

**** yall took me to skool on this subject lol to many different know it alls in here no offense to those of you that really know what your talking about though.... and to me it sounds like the only one that knows what there talking about is jlaine

 

[ngsm13 5,000+ posts]

Originally posted by jlaine Yes, and I've taken basic analog electronics nearly 10 years ago, and I still know you are grasping at straws.

 

In fact, with what you've just said there, you know absolutely nothing about amplifier topology or electronics in general I'd say. Converting sound into an electrical wave happens in an amp? Are you daft? How the hell do you even get "sound" into an amp? Sound is excited air molecules, where is the AIR INLET on an amplifier?

 

I've designed and built amplifiers in my lifetime, have you?

 

 

 

Hello... First lets try to get away from "pushing" things, I hate that generic highschooler term.

Ohms law, BREAK IT DOWN. E = I*R

 

You have VOLTAGE and you have RESISTANCE. CURRENT IS AUTOMATICALLY THERE.

 

Can it be any clearer?

 

Here.. I'll help..

 

CURRENT (I) = VOLTAGE divided by RESISTANCE

 

Why do we measure VOLTAGE?

 

Answer is elementary. Current measuring devices operate on a magnetically induced field and don't react fast enough under most cases.

 

It is measuring an ACTIVE circuit. You have VOLTAGE, you have RESISTANCE, and (this is the hard part for you, but follow me here...) you have a VOLTAGE source! Amplifiers are VOLTAGE sources, NOT current sources. Current is passed based on the electrical pressure created by the circuit.

 

Hi... I am a watt.

 

I am measured by:

 

P= IxE

P= E^2/R

 

A little common math...

 

P = I x E

 

I = E/R

 

THEREFORE

 

P = E/R x E

 

THEREFORE

 

P = E^2/R

 

Did you grab all of that and hold it tight, it's right there, common algebra!

 

 

 

I assure you, you have NOT burst my bubble.

 

Have you never heard of burst ratings?

 

Here is a really dumbed down example:

 

Why can a battery charger be rated for 250A for 4 seconds, when it's standard duty cycle is for 40A at 100%?

D A M N !

i owuld have to say... OWNED!!!! on behalf of jlaine's extensive knowledge on the subject. That was just great...one of the best i've seen since zane. but, i'll be back later...get some "owned" pics. Jlaine is the masta pimp! lol, peace guys.

NG

 

[marauder 10+ year member]

yes he is the master pimp he OWNED me for sure. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

look i cannot say that he is incorrect his formula does figure for the current of a circuit no doubt. and as for the excessive power yes i'll give you that an amp may produce a very large amout of power for a split second but the last time i checked we were talking about a sustained load. i'd like to see an amp that can constantly exceed it's potential by 15-20% and do it constantly.

ok with your formula p=e^2/r it will show the potential current of a circuit. does it reflect the actual current in a circuit? yes but you must use the source values (the amp) to put into these figues. that will give you the potential power of the circuit

ok this discussion was origonally about the RMS value to PEP or peak conversion so that's where i'm going back to since no-one else seems to understand how music gets converted into electricity and back. (and PS yes i said amp in a earlier post when i should have said head unit my brain got ahead of my fingers and i left a step out. i can admit when i posted something that was incorrect).

now in the next post i'm posting 4 pages out of my electrical principles book that shows that wattage is calculated by voltage multiplied by the amperage. and that the RMS to PEP or peak value is derived by the 1.414/.707 values.

again this is my last posts on this matter and you can believe what you want to believe. i personally will noe believe that the peak is twice the RMS value no matter what the situation and that the RMS value is the only real value you can use. a wise man once told me that the amplifier sales principle is like a man selling 5 gallon buckes saying that you can put 6 gallons in there. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[marauder 10+ year member]

 

[marauder 10+ year member]

wow they are huge let me resize them and see what happens //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ngsm13 5,000+ posts]

Originally posted by marauder yes he is the master pimp he OWNED me for sure. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

look i cannot say that he is incorrect his formula does figure for the current of a circuit no doubt. and as for the excessive power yes i'll give you that an amp may produce a very large amout of power for a split second but the last time i checked we were talking about a sustained load. i'd like to see an amp that can constantly exceed it's potential by 15-20% and do it constantly.

 

i'm just havin some fun about the masta pimp stuff. BUT, about the sustained load...PEAK is never sustained load. Last time i checked...RMS is the continuous amount of power(or sustained load)...NOT peak. SO, the fact that is a split second is still relevant because that is the very definition of peak power. ANYWAYS...rms is the important value when looking at amplifier power newayz. Like i sed b4, if peak mattered then every1 would be using legacy amps! BUT, i salute both of your on your extensive research/knowledge. Hopefully i'll be at that level someday. peace

NG

 

[marauder 10+ year member]

LOL i think we may have been debating 2 different points perhaps. yes peak is a momentary enomily (spelling). and it goes above the RMS value for definite positive fact.

thanks

 

[jlaine 10+ year member]

Originally posted by marauder LOL i think we may have been debating 2 different points perhaps. yes peak is a momentary enomily (spelling). and it goes above the RMS value for definite positive fact.

 

 

thanks

You know little about amplifer design, this is point blank obvious at this point. The entire "sound input" comment kind of nailed this home for us.

Then there is this, adding more to your inability to understand how amplifiers work:

"that's where i'm going back to since no-one else seems to understand how music gets converted into electricity and back"

That would be because... IT ISN'T! We don't convert it into electricity, that's done AT the recording studio!

It comes off the CD as digital data in binary, either a 1 or a 0. It goes through a digital to analog convertor, which converts it to a LOW LEVEL ANALOG SIGNAL. What's that?

Voltage. Voltage. Voltage. Voltage.

It goes through the head unit, into the amplifier as what?

Voltage. Voltage. Voltage. Voltage.

Gets amplified... NO PROCESSING HERE... AMPLIFIED!

Passes out of the amplifier as the *identical* signal, *amplified.*

Into the voice coil of the subwoofer, where about .5% of it is converted into *acoustical energy.*

Everything you have *tried* to reference is a dumbed-down AC fundamentals booklet that covers pure sine waves and the root-mean-square of them.

You need to read up more - understand music fundamentals, examine a musical signal under an oscilliscope, and then undertand what RMS means.

root-mean-square.

What happens when you have not a sine wave with a nice parabolic curve, but a musical signal... What happens to that root-mean-square.

Think about it.

 

[marauder 10+ year member]

ok you can believe as you will that the peak amplifier rating is twice the RMS value if you want i'll no longer continue this debate since i know nothing about how these things //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif LOL. believe as you will while those who truly know actually know. and as for the oscilliscope comment i have looked at sound and it's simply an impure sinewave that still rises, peaks, and then falls just like a pure sine wave and the magnitudes are the same at given volume. so therefore the power cannot be higher since the values are relatively the same only the frequencies are different.

thanks, and have a nice day.