Testing Watts?

[Lucid15 10+ year member]

Is there a way to test how many watts your amp is putting out? without expensive equipment of course. I want tosee if my PCA-2000D is putting out close to what it is supposed to

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[lil_italy773 10+ year member]

Is there a way to test how many watts your amp is putting out? without expensive equipment of course. I want tosee if my PCA-2000D is putting out close to what it is supposed to

u have a clamp DMM, and a DMM if so PM me and ill tell u what u need to do. i clamp all my amps to see real rms

 

[themommyvan 10+ year member]

you enclosure has EVERYTHING to do with impedance of your subs.

here is an example.. you have a dual voice coil 2 ohm sub. you have it wired to your amp at 1 ohm.

your amp says it will give you 2thousand watts at 1ohm.

but you arent loud, and you have everything set perfect.

then you check your amp with a clamp meter and a dmm and find out you are only getting about 500 watts.

what!?!? only 500 watts from my two thousand watt amp !?!?!

then you, along with a million other people who dont know.. go on the internet and start slamming that amp, saying it doesnt put out rated power.

but, had you known better, you would have also done the math the opposite way... and found out that you were only getting 500 watts because with box rise your sub was actually playing at 4ohms!!!!

so now, you are getting 500 watts at 4 ohms, and that just happens to be exactly what that amp is rated at.. hmm not overrated anymore is it.

then you change your box, get a lower load, etc... and get more power from your amp.

but, you will still never see that 2kw because you have a 1ohm sub, and your amp makes that power at 1ohm, but you will never get a 1ohm sub to play at 1ohm. god wont even accomplish that.

i dont know of anyone who knows how to figure what your box rise will be. there have been countless discussions. there are so many things that affect box rise, and none of them are constant in every enclosure or vehicle. so the only way to know is to build the box and test it. then you'll know the box rise. but.. put that same box in a different car and you get totally different resutls.

box rise is affected by teh sub, the box, the amp, the battery, the alternator, the temperature, the cabin of the vehicle, the trunk ,the windows, etc...

its trial and error.

so, the only formula there is, is for testing the box rise after its built and everything is connected.

those formulas are very simple, and readily available. and easy enough to perform with the right tools.

you'll need a good digital multimeter.

you'll need a good digital clamp meter.

a pen and paper

and a buddy.

you hook up your amp, sub, etc... get it all connected.

then you clamp the clamp meter on the positive speaker wire. ONLY on the positive wire.. and clamp it as close to the amp as possible. (i clamp about 2" from the amp terminal)

then you connect your dmm to the positive and negative speaker wires. pos to pos and neg to neg.

set your clamp meter to 100 or 200 ac amp range. whichever is the lowest your clamp offers.

set your dmm to 200 ac volts.

now, get ready to play some test tones...

as you playt your tones.. you want to play them long enough for the meters to stabilize thier readings.

you and your buddy should each be in charge of reading one meter. because it can be difficult to try and remember the peak you saw on each of them. (if you have a higher dollar clamp with PEAK hold (not data hold) then you can set it to hold the peak amperage it sees, then you only need to remember the ac volts)

after each tone, you should write down the peak ac amps and the peak ac volts.

now is the fun part.. the math...

acvolts X acamps = real watts used (this is the actual amount of watts your amp produced at that frequency and volume control)

acvolts / acamps = reactive ohm load (this is your REAL ohm load when playing that frequency.)

so.. lets look at some real world examples....

joe dirt has a 3000 watt amp.

it's rated for :

1000 @ 4-Ohms

2000 @ 2-Ohms

4000 @ 1-Ohm

he has read that it only does around 3000 watts @ 1ohm, on forums (mostly from peopel who have no clue and have never used or tested that amp) so everyone says that amp is waaaay overrated, by at least 1000 watts.

so, joe goes and gets one. he hooks it up in his car on his super duper fancy beefy compettiion sub with giant motor and super cool dustcap, this is a competition sub so it has dual 1 ohm coils, so he wires the coils together and hooks it up to the amp at 1/2 ohm because at 1/2 ohm it should put out superunbelievableginormous amounts of power.

he hooks up his clamp meter and his dmm.

he gets out his pad and paper, and starts going through his bass cd's test tones, playing heach tone looking to find out what his peak frequency is, and then playing that peak frequency at every volume level until he thinks its distorting so he stops there.

at the end of it all, he looks to see which volume level and frequency gave the msot power..

low and behold, he's in for a few surprises.

first of all, he thought his peak frequency was 35 hz, because thats what his enclosure is built to.. but hediscovers that with in car gain.. his peak is actually 53 hz .

then he discovers that even though his sub is connected to his amp at 1/2 ohm.. he's actually waaaay above that.

he figures it out with the math.

we'll say that his peak frequency gave him the following readings...

71.4 ac volts

31.8 ac amps

so...

71.4v X 31.8a = 2270 real watts

so dangit.. they were right on those forums.. his 3000 watt amp hooked up at 1/2 ohm only does 2270 watts.

man, now hehates that manufacturer and slams them on every forum because his amp is overrated by almost twice as much...

but....

had he done the REST of the math....

71.4v / 31.8a = 2.24 ohms

he would have realized that his sub, while hooked up at 1/2 ohm.. was actually playing at 2.24 ohms because he has such a huge box rise.

so now... is his amp still overrated?

it claims to do 2000 at 2 ohms... and he is doing 2270 at 2.24 ohms.

looks to me like his amp is actually UNDERated.. and worthy of some praise instead of being slammed all the time.

so, joe takes this newfound knowledge and builds himself a new enclosure, he has no idea if it will be better or worse, but hes prepared to find out...

his new box, with the same amp and the same sub, gives him the following result....

70.1 ac volts

59.5 ac amps

so...

70.1v X 59.5a = 4170.95 watts

and

70.1v / 59.5a = 1.17 ohms

holy moley joe is making 4170.95 watts @ 1.17 ohms from an amp thats only rated for 4000w at 1 ohm !!! looks to me like his amp is UNDERrated even more than he thought it was.

and look at that, he went from 2.24 ohms down to 1.17 ohms just from building a more effecient box.

AND... the best part.. he gained 1900.95 REAL watts... and didnt buy any new equipment to do it... all he did was build a new box.

Now joe will go out onto forums with REAL WORLD numbers, and actual tests that he hs done, and instead of jumping on a hate bashing bandwagon, with a bunch of people that dont have real world experience wit hthat particular amplifier, and he'l lgive them real results and a real opinion, based on real experience, not based on something he read on a forum that was posted from peole without said real experience.

and this is the reason that people that dont know what they are doing tend to claim that certain amps are overrated or underrated, when in fact they have never clamped the amp to see what thier box rise, ohm load, or power was.

and of course.. lets not forget that joe saw these results on a burp, with his peak frequency, ie: the most perfect note for his car, on the most perfect volume for his car.

but can yo uguess what happens when he pops in a music cd.... you got it.. the music is dynamic. the volumes and the notes are ever changing. so the reactive load is going to change CONSTANTLY, as is the overall power output.

 

[lil_italy773 10+ year member]

nevermind he said it all excacly the way it needs to be. i just wasnt gonna type all that. great post responce mommyvan!

 

[dumpin907 10+ year member]

themommyvan knows his ish listen to this guy.

 

[themommyvan 10+ year member]

I wish they would sticky it. Makes it easier for everyone. That info is from Pornstar (Jay Thompson).

 

[Lucid15 10+ year member]

Wow thanks alot, but im sorta new so all this was kinda confusing. I have a non-digital DMM but i dont think i have a clamp meter, nor do i know what one is. Mommy, this post should be a sticky man. Good info for the vets, but im still confused lol

 

[Lucid15 10+ year member]

I think i have a pretty good box, it was built by vitveet. Can someone pm me, so i dont look like an idiot haha

 

[themommyvan 10+ year member]

Clamp meter

http://www.myflukestore.com/p1244/fluke_321.php

 

[dumpin907 10+ year member]

clamp meter=expensive....

 

[Lucid15 10+ year member]

Lets just say my amp is pushin 3000000 watts //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif lol

 

[themommyvan 10+ year member]

clamp meter=expensive....

Yes but a good investment.

 

[helotaxi 5,000+ posts]

On the whole, unless you are competing and need to figure box rise, there is no reason to test the output of your amp. If it's slightly underrated, the difference will not be audible. If it's slightly overrated, the difference still won't be audible. If you are serious about competing, you'll drop the money on a proven amp anyway. If you're building a system for your own pleasure, the only thing you care about is is it is or is it isn't loud enough. If it is, then the answer to how much power your amp makes is "enough." If it isn't loud enough, but sounds good, then the box is probably right, so I wouldn't go trying to tinker with the box rise and risk messing up the sound when simply getting a bigger amp is the better answer.

 

[jbizzle 5,000+ posts]

nice write up

 

[lilmaniac2 5,000+ posts]

you enclosure has EVERYTHING to do with impedance of your subs.
here is an example.. you have a dual voice coil 2 ohm sub. you have it wired to your amp at 1 ohm.

your amp says it will give you 2thousand watts at 1ohm.

but you arent loud, and you have everything set perfect.

then you check your amp with a clamp meter and a dmm and find out you are only getting about 500 watts.

what!?!? only 500 watts from my two thousand watt amp !?!?!

then you, along with a million other people who dont know.. go on the internet and start slamming that amp, saying it doesnt put out rated power.

but, had you known better, you would have also done the math the opposite way... and found out that you were only getting 500 watts because with box rise your sub was actually playing at 4ohms!!!!

so now, you are getting 500 watts at 4 ohms, and that just happens to be exactly what that amp is rated at.. hmm not overrated anymore is it.

then you change your box, get a lower load, etc... and get more power from your amp.

but, you will still never see that 2kw because you have a 1ohm sub, and your amp makes that power at 1ohm, but you will never get a 1ohm sub to play at 1ohm. god wont even accomplish that.

i dont know of anyone who knows how to figure what your box rise will be. there have been countless discussions. there are so many things that affect box rise, and none of them are constant in every enclosure or vehicle. so the only way to know is to build the box and test it. then you'll know the box rise. but.. put that same box in a different car and you get totally different resutls.

box rise is affected by teh sub, the box, the amp, the battery, the alternator, the temperature, the cabin of the vehicle, the trunk ,the windows, etc...

its trial and error.

so, the only formula there is, is for testing the box rise after its built and everything is connected.

those formulas are very simple, and readily available. and easy enough to perform with the right tools.

you'll need a good digital multimeter.

you'll need a good digital clamp meter.

a pen and paper

and a buddy.

you hook up your amp, sub, etc... get it all connected.

then you clamp the clamp meter on the positive speaker wire. ONLY on the positive wire.. and clamp it as close to the amp as possible. (i clamp about 2" from the amp terminal)

then you connect your dmm to the positive and negative speaker wires. pos to pos and neg to neg.

set your clamp meter to 100 or 200 ac amp range. whichever is the lowest your clamp offers.

set your dmm to 200 ac volts.

now, get ready to play some test tones...

as you playt your tones.. you want to play them long enough for the meters to stabilize thier readings.

you and your buddy should each be in charge of reading one meter. because it can be difficult to try and remember the peak you saw on each of them. (if you have a higher dollar clamp with PEAK hold (not data hold) then you can set it to hold the peak amperage it sees, then you only need to remember the ac volts)

after each tone, you should write down the peak ac amps and the peak ac volts.

now is the fun part.. the math...

acvolts X acamps = real watts used (this is the actual amount of watts your amp produced at that frequency and volume control)

acvolts / acamps = reactive ohm load (this is your REAL ohm load when playing that frequency.)

so.. lets look at some real world examples....

joe dirt has a 3000 watt amp.

it's rated for :

1000 @ 4-Ohms

2000 @ 2-Ohms

4000 @ 1-Ohm

he has read that it only does around 3000 watts @ 1ohm, on forums (mostly from peopel who have no clue and have never used or tested that amp) so everyone says that amp is waaaay overrated, by at least 1000 watts.

so, joe goes and gets one. he hooks it up in his car on his super duper fancy beefy compettiion sub with giant motor and super cool dustcap, this is a competition sub so it has dual 1 ohm coils, so he wires the coils together and hooks it up to the amp at 1/2 ohm because at 1/2 ohm it should put out superunbelievableginormous amounts of power.

he hooks up his clamp meter and his dmm.

he gets out his pad and paper, and starts going through his bass cd's test tones, playing heach tone looking to find out what his peak frequency is, and then playing that peak frequency at every volume level until he thinks its distorting so he stops there.

at the end of it all, he looks to see which volume level and frequency gave the msot power..

low and behold, he's in for a few surprises.

first of all, he thought his peak frequency was 35 hz, because thats what his enclosure is built to.. but hediscovers that with in car gain.. his peak is actually 53 hz .

then he discovers that even though his sub is connected to his amp at 1/2 ohm.. he's actually waaaay above that.

he figures it out with the math.

we'll say that his peak frequency gave him the following readings...

71.4 ac volts

31.8 ac amps

so...

71.4v X 31.8a = 2270 real watts

so dangit.. they were right on those forums.. his 3000 watt amp hooked up at 1/2 ohm only does 2270 watts.

man, now hehates that manufacturer and slams them on every forum because his amp is overrated by almost twice as much...

but....

had he done the REST of the math....

71.4v / 31.8a = 2.24 ohms

he would have realized that his sub, while hooked up at 1/2 ohm.. was actually playing at 2.24 ohms because he has such a huge box rise.

so now... is his amp still overrated?

it claims to do 2000 at 2 ohms... and he is doing 2270 at 2.24 ohms.

looks to me like his amp is actually UNDERated.. and worthy of some praise instead of being slammed all the time.

so, joe takes this newfound knowledge and builds himself a new enclosure, he has no idea if it will be better or worse, but hes prepared to find out...

his new box, with the same amp and the same sub, gives him the following result....

70.1 ac volts

59.5 ac amps

so...

70.1v X 59.5a = 4170.95 watts

and

70.1v X 59.5a = 1.17 ohms

holy moley joe is making 4170.95 watts @ 1.17 ohms from an amp thats only rated for 4000w at 1 ohm !!! looks to me like his amp is UNDERrated even more than he thought it was.

and look at that, he went from 2.24 ohms down to 1.17 ohms just from building a more effecient box.

AND... the best part.. he gained 1900.95 REAL watts... and didnt buy any new equipment to do it... all he did was build a new box.

Now joe will go out onto forums with REAL WORLD numbers, and actual tests that he hs done, and instead of jumping on a hate bashing bandwagon, with a bunch of people that dont have real world experience wit hthat particular amplifier, and he'l lgive them real results and a real opinion, based on real experience, not based on something he read on a forum that was posted from peole without said real experience.

and this is the reason that people that dont know what they are doing tend to claim that certain amps are overrated or underrated, when in fact they have never clamped the amp to see what thier box rise, ohm load, or power was.

and of course.. lets not forget that joe saw these results on a burp, with his peak frequency, ie: the most perfect note for his car, on the most perfect volume for his car.

but can yo uguess what happens when he pops in a music cd.... you got it.. the music is dynamic. the volumes and the notes are ever changing. so the reactive load is going to change CONSTANTLY, as is the overall power output.

STICKY!!!!