Question about hooking a 2 subs to a box (Car Audio)

[annunaki]

Too bad I do this for free.

 

[mulester7]

.....sure, of course....thanks......

 

[zumbo]

SOmeone had mentioned 1 ohm in the post before me. Tell me how you get 2 4 ohm woofers to 1 ohm??

Anywhos, go with 2 ohms, and buy my old amp that I used to power my Kappa Perfect.

Precision Power PCX-1250. 500 watts RMS @ 2 ohms.

Paul

Parallel=2ohm. That 2ohm load bridged on a 2ohm stable amp is too much. A 2ohm stable amp is not stable bridged with a 2ohm load. You have to assume the amp is seeing a 1ohm load.
An amp that is 2ohm stable bridged, is in fact 1ohm stable.

 

[zumbo]

SOmeone had mentioned 1 ohm in the post before me. Tell me how you get 2 4 ohm woofers to 1 ohm??

Anywhos, go with 2 ohms, and buy my old amp that I used to power my Kappa Perfect.

Precision Power PCX-1250. 500 watts RMS @ 2 ohms.

Paul

Yes, your amp would be great. PM RecLodossWar and see if he wants it. I think he's not in the US.

 

[mulester7]

.....so, a recommendation to a board member to help satisfy another board member's need....Zumbo, a Sterling Act indeed....brought a tear to my eye....kinda' like the tear brought an hour or so ago when it hit me my system is having to cripple through with a damned McIntosh 2200 slave amp........how can life be this cruel?....where did I fail?....

 

[Francious70]

Parallel=2ohm. That 2ohm load bridged on a 2ohm stable amp is too much. A 2ohm stable amp is not stable bridged with a 2ohm load. You have to assume the amp is seeing a 1ohm load.
An amp that is 2ohm stable bridged, is in fact 1ohm stable.

Most 2 channel amps are not 2 ohms bridged stable. For that to be true, the amp would have to be 1 ohm stereo stable, which VERRRRRRRY few are. The way I was told how impedance works when bridged is each channel sees 1/2 of the total impedance. in this case it's 2 ohms, so each channel see 1 ohm.

So, after that whole spiel, I'm just agreeing with you.

Anywhos, Phoenix Gold's MPS series of smps ARE in fact 2 ohm bridgeable.

Paul

 

[zumbo]

If I was back into car audio, Phoenix Gold amps would be my choice.
Alpine head unit.
MB Quart mids and tweets.
JL subs.

All in a Scion xB.

 

[annunaki]

Most 2 channel amps are not 2 ohms bridged stable. For that to be true, the amp would have to be 1 ohm stereo stable, which VERRRRRRRY few are. The way I was told how impedance works when bridged is each channel sees 1/2 of the total impedance. in this case it's 2 ohms, so each channel see 1 ohm.
So, after that whole spiel, I'm just agreeing with you.

Anywhos, Phoenix Gold's MPS series of smps ARE in fact 2 ohm bridgeable.

Paul

Please see the link I posted when replying to Zumbo about this matter. That way of thinking may help you, but it is not correct.

 

[Francious70]

Which of the 17 pages would this link be on?? Beginning, middle, end??

Paul

 

[annunaki]

Sorry Paul,

I almost forgot where it was.

This part:

2 Ohm Stereo vs 4 Ohm Mono Loads

There seems to be some confusion as to why a 4 ohm mono and a 2 ohm stereo load are the same, as far as the amplifier is concerned. When two 4 ohm speakers are connected to each channel of a 2 channel amplifier, the amplifier is capable of driving the speakers with half of the total power supply voltage. If the amplifier has a power supply which produces plus or minus 20 volts, it will not be able to drive the speakers on a single channel with any more than 20 volts at any point in time. If we have a 2 ohm load on each channel, at the highest point on the waveform the amplifier will apply 20 volts to the speaker load. Remember that we are only considering a single point in time for this example. If we go back to ohms law...

I=V/R
I=20/2
I=10 amperes

If we take a single 4 ohm speaker and bridge it on that same amplifier, the amplifier will be able to apply twice the voltage across the speaker. This is because while one speaker terminal is being driven positive (towards the positive rail), the other terminal is being driven towards the negative rail. This will allow the entire power supply voltage to be applied to the speaker's voice coil. It will now be able to drive the 4 ohm speaker with 40 volts instead of 20 volts in the previous example. Back to Ohm's law...

I=V/R
I=40/4
I=10 amperes

The same amount of current flows through the output transistors whether the amplifier is driving a 4 ohm mono load or 2 ohm stereo load. As far as the amplifier is concerned, they are the same load.


--------------------------------------------------------------------------------


NOTE:
Some people say that when an amplifier is bridged onto a 4 ohm load, it 'sees' a 2 ohm load. While it is true that the same current flows whether the amp is bridged on a 4 ohm load or a 2 ohm stereo load, the amplifier is driving a 4 ohm load across its outputs. A single 4 ohm speaker can never be a 2 ohm load.


http://www.bcae1.com/bridging.htm
__________________

 

[Francious70]

Yea, I've read bcae1.com hundreds of times thru. I was just stating the impedance charateristics of why a 2 ohm stereo capable amp cant work with a 2 ohm bridged load.

^^^Does that make any sence?? I'm enjoying this thread.

Paul

 

[annunaki]

Yes, it does.

I guess I am just being technical, but I have always been a stickler for detail. Your way does work, but it is not really true. Sorry.

 

[Francious70]

Hey man, I love to read technical stuff. How do you expect to learn stuff if there's just fluff. It's when you start getting into Engineering stuff that it starts to fly over my head.

Paul