Question about the level on my amp.

[legalizeeit 420]

So i have 2, 1000 Watt JVC subs. I have an 1800 watt 4 channel amp. So i have them wired in a series. Is it okay to turn my gain or level all the way up because im not puttin out 1000 watts or would that still be bad for the speakers?

[mastodon]

So you wired the subwoofers (passive, I assume) in series and want to connect them to the amp? What channel on the amp, or bridged? What impedance are the woofers?

If you have 2 subs, why would you connect them in series as opposed to using one for each channel?

[xeclipse]

Bridge two channels and feed each btl outputs to one sub each.Make sure that each channel is capable of driving half the nominal impedance of the subs.

[Andy5112405]

The amp will certainly be providing reduced power into the two subs in series so you should be OK to go all the way up.

Most amps specify their full power into low impedance - for example 2 Ohms. Into 4 Ohms the power roughly halves and into 8 Ohms it halves again.

If you are using 1000W 4 Ohm subs in series, the amp will be seeing 8 Ohms. Its output is probably only 500W and that will be PMPO. However, the subs may also be specified at PMPO so all should be OK.

PMPO is an inexact science and doesnt reflect the true power in a system. If you can find the RMS power specs we might be able to be more definitive.

You might be disappointed. 1800W PMPO may only equate to 20 or 30W RMS.

[mastodon]

For sake of the neighbors, I sure hope we're talking about PMPO levels here...1kW RMS is not audio, it's seismology.

[Andy5112405]

ICE - In Car Entertainment is the biggest culprit when it comes to PMPO.

For an 1800W RMS sub-amp you would need approximately 2300W of power (if it was a VERY efficient Class D amplifier).

This would equate to 160A of current from the poor 12V battery. (And that's assuming that its terminal voltage can be sustained at 15.6V with a MASSIVE alternator)

However, you would not be able to drive the amp at full RMS output continuously as the dynamic range of the music would require "headroom", approximately 40dB of headroom in a decent set-up.

I wont go into the maths here as they have been extensively covered many times.

Your 1800W PMPO amplifier can probably provide VERY SHORT periods of 1800W but will generally run at MUCH LESS power. If it is a 4 Channel amplifier, then the buggers will have added the PMPO figures together, so each channel is probably only 450W PMPO. Can you see how they are selling to the young boy racers amongst you.



PMPO is defined as the MAXIMUM POWER that can be provided before the amplifier is destroyed. ICE manufacturer are clever, they measure their equipment with ridiculously engineered sources and at the moment of destruction, calculate the PMPO.

[AndrewT]

Originally Posted by legalizeeit 420

Is it okay to turn my gain or level all the way up because im not puttin out 1000 watts or would that still be bad for the speakers?

measure the input and output of the amp feeding open circuit and a dummy resistive load.

[madtecchy]

Hi Andy 5112405
RMS Route mean square. what about peak ??????????.
You have just taught me that the 1000 va transformer i loosley sugested to a memmber for running his car amp was way to big also. also you hve imformed me that it needed to be 2000va. If i did not know better i would be very confused.
regards Mad Mark

[legalizeeit 420]

So my amp is a piece of ****... I got it for free. Im just gunna turn it all the way up, hopefully the amp doesn't get destroyed. But i got lots of tinsel wire for my subs. My Amp model number is in my bio.

[Andy5112405]

Originally Posted by madtecchy

Hi Andy 5112405
RMS Route mean square. what about peak ??????????.
You have just taught me that the 1000 va transformer i loosley sugested to a memmber for running his car amp was way to big also. also you hve imformed me that it needed to be 2000va. If i did not know better i would be very confused.
regards Mad Mark

Suggesting anything other than a large battery for a car amp is always dangerous as these things are designed to draw power from the huge resources of an ICE fit.