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Discussion Starter · #1 ·
I read something about if a Power Amplifier has lets say it rates 1000W @ 4ohm, then what are the real RMS?


Somewhere in this forum I read that most Power Amplifiers if it rates "x" quantity of Watts; not necessarily means it rates as RMS.


Is there a formula for this or something?


I have a sub driver that rates 1000W RMS @ 4ohm; 2000W Peak; I'm going to use it in a sealed enclosure; but I want to make sure what amplifier is suitable for the driver. I believe a 1000W Amp should be enough; but Im not sure if this 1000W @ 4ohms is in reality 1000W RMS! or if I need a higher rated amp.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by CZ Eddie /forum/post/20835499


First thing to do is find out how much power the sub can handle in the enclosure before exceeding x-max.

No idea about this. All I know the driver specs are: SVC 4ohm 1000W RMS, 2000W Peak.


I will use the new Inuke 6000DSP, but maybe the 3000DSP is enough. On the web someone received an email from Behringer that rating for Inukes are PEaks.


RMS (SineWave) should be (Peak x 0.707). So if the 3000 model is:


2 x 1500W @ 2 ohm, then 1060W are RMS?

2 x 880W @ 4 ohm, then 622W are RMS?


If so, then 622W is good but not enough to really push the driver to its limits due that driver can handle 1000W RMS?


6000 Model delievers:

2 x 3000W @ 4ohm = 2121W RMS; now is this overpowering the driver??

2 x 1500W @ 8ohm


What I do not understand is that after 3 seconds it drops from 600W to 375W. How bad is this for HT?

This info was taken from this link: http://www.soundforums.net/live/thre...mplifier/page3


RMS (sine wave)

8 Ohm 2x312

4 Ohm 2x600 (2x375 after 3 seconds)

2 Ohm 2x1176 (2x750 after 1 second, protect after 5 seconds)
 

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It won't matter much if your driver hits x-max at 300W input in your enclosure.


Try to find the driver model # and t/s parameters, then post the size of the box and the info. Someone will help out.


For amp power ratings, check out the measured watts of some models in the AMP sticky thread at the top of the forum and compare that against the rated watts.
 

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Quote:
Originally Posted by javygonx /forum/post/20835558


RMS (SineWave) should be (Peak x 0.707).

Your formula for calculating RMS power is flawed.

First of all, RMS really only applies to Voltage (V) and Current (I) as it gives the DC equivalent of a sinusoidal waveform in order to calculate the power (P) dissipated in a resistive load.

(Example: A 14.1Vpk sine wave has the DC equivalent heating power of a 0.707 x 14.1Vpk = 10VDC signal)


To calculate average power dissipated in a resistive load you multiply (0.707 x Vpk) by (0.707 x Ipk) to equal (0.5 x Ppk).

Hence the average power dissipated in a resistive load is naturally one half the peak power, (0.707 x 0.707 = 0.5) which is also the RMS power. (For power, RMS only implies that a sine wave was used as the waveform signal)



Also, the FTC (Federal Trade Commission) stipulated years ago that an amplifiers power rating has to be in the format of X Watts continuous RMS over a frequency range of Y Hz (typically 20Hz-20kHz) with distortion no greater than Z%. Somewhere in Behringers spec sheet there should be this kind of information available. I would hope that Behringer doesn't use peak power levels in the rating of their amplifiers.
 

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^^^ Beat me to it by a few minutes.


OP, there is no such thing as peak or music power, they are just BS. Any reputable manufacturer will also state the conditions and test methodology used.

What I do not understand is that after 3 seconds it drops from 600W to 375W. How bad is this for HT?

This info was taken from this link: http://www.soundforums.net/live/thre...mplifier/page3



It most likely means that it does not have enough power supply capacity to meet a continuous signal.
 

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Discussion Starter · #8 ·
Ok; then to help me out. If the sealed enclosure measures: 19x19x22; its about 3.5 cf and Sub Driver Parameters are the following then what INuke should I get: 3000 or 6000? I will start with one sub and add another sub by Christmas!


Revc = 2.9001 ohms

Fms = 27.8340 Hz

Zmax = 21.4774 ohms

Qes = 0.7948

Qms = 5.0914

Qts = 0.685

Sd = 490cm^2

Vas = 70.3680 L

BL = 10.4 N/A

Mms = 169.4703 g

Sensitivity = 84.5559 dB @1W/1m

Sensitivity = 88.9626 dB @2.83Vrms/1m

Xmax = 32mm total

Usable Excursion = 3" total

Displacement in enclosure - .13 ft^3

Weight - 27 lbs


UPDATE:


I got official PSI HT Custom Sub Parameters: How good or worst is vs the original Platform 1 version?


Revc = 4.01 ohms

Fms = 24.2777 Hz

Zmax = 35.4840 ohms

Qes = 1.0747

Qms = 8.0662

Qts = 0.9484

Le = 5.2537 mH (at 1 kHz)

Diam = 330.2000 mm ( 13.0000 in )

Sd = 85633.5536 mm^2(132.7323 in^2)

Vas = 114.5520 L ( 4.0454 ft^3)

BL = 15.2125 N/A

Mms = 390.8193 g

Cms = 109.9639 uM/N

Kms = 9093.8896 N/M

Rms = 7.3908 R mechanical

Efficiency = 0.1433 %

Sensitivity= 83.5807 dB @1W/1m

Sensitivity= 86.4081 dB @2.83Vrms/1m
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by LTD02 /forum/post/20840044


not sure 84.5 db 1w1m is going to need a big block motor to motivate it.


does it have a power handling specification?

Power handling is: SVC 4ohm 1000W RMS; 2000W Peak. I'ts that what you mean?
 

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Quote:
Originally Posted by javygonx /forum/post/20839980


Ok; then to help me out. If the sealed enclosure measures: 19x19x22; its about 3.5 cf and Sub Driver Parameters are the following then what INuke should I get: 3000 or 6000? I will start with one sub and add another sub by Christmas!


Revc = 2.9001 ohms

Fms = 26.8340 Hz

Zmax = 21.4774 ohms

Qes = 0.7048

Qms = 4.0914

Qts = 0.595

Sd = 640cm^2

Vas = 90.3680 L

BL = 15.5 N/A

Mms = 329.4703 g

Sensitivity = 84.5559 dB @1W/1m

Sensitivity = 88.9626 dB @2.83Vrms/1m

Xmax = 32mm total

Usable Excursion = 3" total

Displacement in enclosure - .14 ft^3

Weight - 29 lbs

Okay, here you go.


YELLOW = .707 recommended enclosure size (a bit over 5 cu.ft.)

BLUE = 3.5 cu.ft.

No EQ but with 20hz HighPass - Max SPL before hitting x-max


no EQ or HighPass - max watts before hitting XMAX


 

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So,


If you go without using any EQ at 20hz and no High Pass, then max watts is 1600 before hitting x-max (10hz & above).


If you add a 3db bump at 20hz, then max watts is 900 before hitting x-max.


If you add a 20hz high pass (but no 3db bump), then max watts is 2600 before hitting x-max.
 

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Discussion Starter · #14 ·

Quote:
Originally Posted by CZ Eddie /forum/post/0


So,


If you go without using any EQ at 20hz and no High Pass, then max watts is 1600 before hitting x-max (10hz & above).


If you add a 3db bump at 20hz, then max watts is 900 before hitting x-max.


If you add a 20hz high pass (but no 3db bump), then max watts is 2600 before hitting x-max.

I do not understand too much, but does the Inuke have low pass and high pass filter? If so, which one I need to setup the sub; high pass or low pass? Get 3000 or 6000?
 

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Discussion Starter · #15 ·
Holy crap! The sub driver arrived. Its at post office but right now Hurricane Irene is passing!!! Cant pickup tomorrow. Strong winds and rains. Right now there is a power outage.
im using my iphone.
 
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