Follow up on mixing subs

[hoxie08 5,000+ posts]

Okay, it was explained to me yesterday, but I got to thinking (should have known better) and confused myself...AGAIN lol. Lets try this scenario...

500 watt mono block amp...

2x 10w3v2 Dual 4 Ohms Voice coils...

Now according to this site http://www.the12volt.com/caraudio/boxcalcs.asp#ser if i wired them in parallel, one sub at 8 ohms and one at 2 ohms, I would get a load of 1.6 ohms...

I see a JL 500/1 amp can run a load down to 1.5 ohms, if the final load was 1.6 ohms I dont understand how it would imbalance the power distributed to the two subs, since the amp doesnt see them seperately, just as a single 1.6 ohm load....

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[dvrmstrng 5,000+ posts]

just stop

 

[JustStoppingBy 10+ year member]

*** dammit.

wire them to 1 ohm (both @ 2 ohms parralel) or wire them to 4 ohms..

and BE DONE WITH IT. If i recall, JL amps run the same RMS wattage from 1.5 to 4 ohms?

 

[hoxie08 5,000+ posts]

*** dammit.

wire them to 1 ohm (both @ 2 ohms parralel) or wire them to 4 ohms..

and BE DONE WITH IT. If i recall, JL amps run the same RMS wattage from 1.5 to 4 ohms?

lol. its just 4 ohms makes less power //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[JustStoppingBy 10+ year member]

see... usually people buy subs and an amp that MATCH UP..

like my RE 15 is 800 RMS at paralell 2 ohms... so i snagged a monoblock that does 800 RMS at 2 ohms...

you know. i hear people do it all the time.

 

[hoss 5,000+ posts]

Okay, it was explained to me yesterday, but I got to thinking (should have known better) and confused myself...AGAIN lol. Lets try this scenario...
500 watt mono block amp...

2x 10w3v2 Dual 4 Ohms Voice coils...

Now according to this site http://www.the12volt.com/caraudio/boxcalcs.asp#ser if i wired them in parallel, one sub at 8 ohms and one at 2 ohms, I would get a load of 1.6 ohms...

I see a JL 500/1 amp can run a load down to 1.5 ohms, if the final load was 1.6 ohms I dont understand how it would imbalance the power distributed to the two subs, since the amp doesnt see them seperately, just as a single 1.6 ohm load....

you halfway answered your own question...

the amp does NOT see them seperatly, you are correct there, it would just see the final impedance load you present to it, and work accordingly to produce the power it is supposed to. however, and here is the kicker... the speakers are at different impedances, they will distribute the power to themselves unevenly. the sub at 2 ohms would see a different amount of power than the sub at 8 ohms, and this can all be confirmed by ohms law.

example, you have an amp putting out 75volts at your 1.6 ohm load (note, 75volts is just a number i made up)

ohms law states voltage = current x resistance

therefore:

75 = current x 2ohms

75/2 = current

current = 37.5

power = current x voltage

power = 37.5amps x 75

power = 2812.5watts @ the 2ohm load

75 = current x 8ohms

75/8 = current

current = 9.375amps

power = current x voltage

power = 9.375 x 75

power = 703.125watts @ the 8ohm load.

so as you see, the speaker wired to 2 ohms would be recieving 2812.5 watts, while the speaker wired to 8 ohms would be recieving 703.125 watts... now do you see how it would give you an unbalanced load?

 

[hoss 5,000+ posts]

lol. its just 4 ohms makes less power //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

are you serious... you quoted him saying it and you still dont understand it...

the 500/1 amp makes the same power at 1.6 ohms as it does at 4 ohms...

it does NOT make less power at 4 ohms...

 

[cotjones 10+ year member]

ok picture it like this....

take a water system...

your amp is the pump, pumping pressure into a line... your subs are facets, releasing that power....

how far open the valves are is equivalent to the ohm load of the speakers...

example #1:

lets say you have both the valves open half way, your total resistance is "X" ohms

example #2:

now lets say you have one valve open 1/4th the way and the other opened 3/4th of the way

the total resistance is exactly the same as above, exept much more water would be coming out of the valve opened 3/4th than the one opened 1/4th...

on the contrary, when the valves are opened equally, (as above the output of the facets will be exactly the same...

now fer ur concern about the 4 ohms, your slash series amp puts out the same amount of power at any load between 1.5 and 4 ohms... there is absolutely no drawback to runing a 4 ohm load on it, it will not have less power than a 1.5 ohm load

 

[andytb 10+ year member]

lol. its just 4 ohms makes less power //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

i thought it puts out the same power through out the ohms

 

[hoxie08 5,000+ posts]

yeah nvm.

 

[hoxie08 5,000+ posts]

see... usually people buy subs and an amp that MATCH UP..

like my RE 15 is 800 RMS at paralell 2 ohms... so i snagged a monoblock that does 800 RMS at 2 ohms...

you know. i hear people do it all the time.

ummm. yeah, theres a reason im asking this, i DONT have the stuff atm, im just saying as PLANNING for the future which would make upgrading easier if I ever wanted to.