Here is the situation. You have 3 speakers two 4 ohm and one 8 ohm. Wiring them 2 4's to make 8 and another 8 to achieve a 4 ohm load. So it has to be off a single channel.(though may be to much power if all speakers are driven dividing up the power) The other option was to run a 2 ohm load and a 8 ohm load.(not an option)

Lastly what I came up with was interesting and not sure how it will work though allow some tweaking. One channel 4 ohms and the other a 8 and a 4 in parallel.....making a 3.66666......ohm load. In this way it might be possible to distribute a higher power to one 4 ohm speaker. Though sadly I can not power that 8 with more power because it can handle it.

Ok after reading all that here is my delema.......2 bass shaker pro's and a single 8 ohm 12" speaker. How to get them to work properly. I can't parallel them all because then it will be something like 1.6 ohms(not good!) The Pro's can handle a good amount of power so im not all that worried about them handeling the power.

The amp im powering them with is a old Auto Tek Model 90 MXI. Puts out 45 watts by 2 at 4 ohms and 220 by 2 at 2 ohms or 440 Mono at 4 ohms. Distortion goes from a tested 0.016 thd 4 ohms to 0.15 thd into 2 ohms stereo or 4 ohms mono. So if it all goes out at 440 to 3 speakers that is 146 watts RMS the Shakers are said to handle 50 watts RMS but im going to power it with a little more!

Anybody have suggestions on what to do or a better solution.
Yea yea I know im supposed to be the pro around here but I still look for suggestions when things get tough!

 

I would try all the combo's that don't overload your amp and see which sounds best.

I would think the best thing to do is this:

Channel 1: Bass shakers in series = 8 Ohms

Channle 2: 12" Speaker = 8 Ohms

Keeps the load stable, but you aren't going to get much power, but with both Bass shakers and a sub, this should still sound good.


-- Robert

 

I assume you're using one stereo output (2 channels) for the bass. Can you run the shakers one on each channel and then connect the 8 ohm woofer bridged across the same two channels?

This assumes the amp is set up for bridging, which if it's rated mono it must be. The effective load on the amp will be 2 ohms on each cahnnel.

 

Most tri-mode setups REQUIRE an identical load across the bridged and stereo channels. Unless you want to fry an amplifier, or the amplifier somehow supports it, don't do it.

MXI in mono to the bass shakers in parallel, 12" in series with the bass shakers = a 4ohm load on the amplifier. Each bass shaker will only see a 1/4 of the output and the sub will see half. I find it unlikely that amplifier will furnish 440 watts RMS at 4ohm mono. You won't fry anything. It will work. It may not be very loud though.

 

Modifry! That is exactly what I am going to do. 2, 4 ohm speakers on 2 channels then one 8 ohm spaker bridged! 440 not enough? You do know that its 440 RMS. The owners manual says exactly how to do it! Its sweet!

 

[QUOTE]Originally posted by jerrypeterson
[B]Most tri-mode setups REQUIRE an identical load across the bridged and stereo channels.

 

[QUOTE]Originally posted by modifry
[B]Not sure I follow you.