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View Full Version : 4 ohm speakers up front, 8 ohm in the rear??



mysilver02alty
01-11-2007, 03:01 AM
I have MB Quart components up front that i'd like to keep.
They need around 100 watts each.

I want to get these Alpha 6a speakers for the rear.http://www.bltsound.com/index.php?crn=16&rn=242&action=show_detail

recommended power for them is around 100 watts.

The MB Quarts are 4 ohm speakers and the Eminence are 8 ohm speakers.

I'd like to power the MB's and the Alphas off one amp. Would i be able to power all four speaker with one of these which i already have?

US Amps AX4300 75 X 4 @ 4 ohms but underrated

Power acoustik rated at 100X4 @ 4 ohms - i think its probably overrated though.


Orion 8004 rated at 100X4 @ 4 ohms

The US Amps amplifier is going to be the clearest amp of the 3.

My question is, is it possible to wire that US Amps amplifier (to give the 4 ohm MB Quarts 90 watts each while giving the Alpha speakers 90 watts each as well)?

If not, what would you recommend??
I dont mind getting matching Alpha speakers up front at all actually. Whatever i do, i dont want to underpower the speakers. Underpowered speakers make me want to take a screwdriver to them. So if you think i should go with a more powerful amp please let me know because it would probably be around the same price.

galacticmonkey
01-11-2007, 03:03 AM
i just made a similar topic... the whole 8ohm thing is confusing

jmanpc
01-11-2007, 03:03 AM
I think it'd be nice to have 8 ohm speakers in the rear, because they would be attenuated. Keep in mind that your goal should be focusing your sound up front, so having your rear speakers be quieter is a good thing.

mysilver02alty
01-11-2007, 03:08 AM
I think it'd be nice to have 8 ohm speakers in the rear, because they would be attenuated. Keep in mind that your goal should be focusing your sound up front, so having your rear speakers be quieter is a good thing.

I know about the whole imaging thing. Ive been contemplating this for like a week :)

Now, do you know what kind of amp you would need to run 4 ohm up front and 8 ohm in rear and get the rated power out of the amp? Or would i have to get 2 different amps.

jmanpc
01-11-2007, 03:10 AM
You can just use any 4-ch. It's just the front set will be getting 75w, and the rears will be getting 37.5w. Which again, isn't a bad thing.

///M5
01-11-2007, 03:13 AM
I think it'd be nice to have 8 ohm speakers in the rear, because they would be attenuated. Keep in mind that your goal should be focusing your sound up front, so having your rear speakers be quieter is a good thing.

They may not be attenuated. If they are 3db more sensitive they will be at the same level. Also note that the sensitivity could be rated at 2.83v for one and 1w for the other making the difference negligible as well.

mysilver02alty
01-11-2007, 03:17 AM
http://www.bltsound.com/index.php?crn=16&rn=242&action=show_detail

My bad, the url i posted in the original post was a dead link. There is the correct link to the Alpha speakers. I just fixed it.

mysilver02alty
01-11-2007, 09:53 AM
You can just use any 4-ch. It's just the front set will be getting 75w, and the rears will be getting 37.5w. Which again, isn't a bad thing.

The rear 8 ohm speakers are rated at 100w rms. I wouldnt want to give them less than like 75 watts. I think it would kind of defeat the purpose of getting that product. I want to maximize their performance. If i was going to do something like that, i'd just stick with my MB Quart 6X9's and not go through with the hassle of spending the money, finding a way to make the speakers fit into that hole & installation, etc.

Why would i bother for a minimal gain.

mysilver02alty
01-11-2007, 10:33 AM
Alright, i just spoke with a stereo installer.

He told me that i could run the front components(4ohm) speakers regular off the left and right input and i could bridge the rear (8 ohm) speakers.

He said that would give me a 4 ohm load to the fronts and rears. he didnt sound too sure of himself though.

Anyone know if this will work?

jmanpc
01-11-2007, 10:44 AM
yes, it will work, but you will lose stereo sound for your rear speakers, and they would be getting more power than the fronts.

mysilver02alty
01-11-2007, 11:11 AM
Anyone know where i could get a diagram of this parallel wiring on something like this? Last thing i want to do is pay a 100.00 install on 75 dollar speakers.

nismos14
01-11-2007, 01:44 PM
Parallel wiring is running the positives of both drivers together to the bridged positive of the amp, and same thing for the negative.

That was goign to be my suggestion, however its gonna be odd not having any stereo seperation in the rear.