jeepbeats,

I think my problem is I just dont understand ohms and amp power yet fully.

yes I went to that basic ar audio website, and I do understand more now... but I have trouble putting it all together.

What Im saying is... how do you know 250-275 watts are going to those subs? Did you actually have to test it, or is it obvious and I just dont understand?

Im also interested to know how many watts would be going to the mids that will be in the doors.

Do the amp's specs show me this somewhere? if they do, I dont understand yet [img]tongue.gif[/img]

I hate being a noob lol

 

To know exactly how many watts are going to the speaker, you'd need a voltmeter and an ammeter to measure current and voltage ...

Power = Voltage x Current

The reason for this is because impedance isn't the same value at all frequencies. For example, a 4 ohm speaker may have an impedance of 50 ohms at 50 Hz but only 3 ohms at 30 Hz ... Obviously it would get more power at 30 Hz ...

However, the nominal impedance is about the average impedance, so setting the gains for X volts and using the formula Power = Voltage*Voltage/Resistance (or Voltage = Square Root of (Power/Resistance), you can get approximately the desired amount of power. A 0 dB test tone ensures that clipping will never occur (unless your amplifier is overrated), but typically won't use the amplifier to its full capacity of the amplifier with music. You may want to set the gains with a -3 dB or -6 dB test tone.

Or just set it by ear and listen closely for distortion [img]smile.gif[/img]

 

I hear what you guys are saying about using a line driver if there is noise, but I ran this amp and sub combo before, and even with the Alpine 9835, I had the sub gains higher than I liked. This is the deck that Dan is running: http://www.audiovox.com/webapp/wcs/s...2558&langId=-1

All I am saying is that it would seem that the MTX amps work better with a higher input signal. In fact, I prefer to use a line driver with every setup I do. And Dan, as far as the power output, I would not be too worried about exact figures. As long as it plays to the volume levels you want, without too much audible distortion, you are good to go. By building a bigger vented (ported) box, you will get more output from the subs, even without changing the amp.

 

Taken from the manual:

Output Impedance: Compatible with 4 – 8 ohm
speakers.
Low-Level Output: 0.7 Volt.

 

Ouch ... Get a new head unit

 

poor mans line driver = use the friggn line level [img]graemlins/laugh.gif[/img]

I won't get too far into it, but when I said the subs can handle 400+RMS, that means thermally with music... that also means look for an amp thats rated for 400Wrms at 2ohms... simple as that...

As jeep pointed out that may be more then is necassary depending on the box they are in...

 

where can brahmas be had at? locally to london?

 

http://www.creativesound.ca/products.php?make=Adire