Bronze Member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 91
Registered: May-05
Some may remember a recent post of mine discussing using a single 12" and two 8's. I wasn't aware of any cancellation issues before when running two 8's on the right channel and single twelve on the left of a single amp.

Now that I have two amps installed, with the 8's bridged to one, and the 12" bridged to the other amp, the cancellation is hugely apparent. Some frequencies hit hard as hell and others just drop out completely creating very unpredictable bass output. Reversing the phase of one amp 180 degrees helps with some music, but worsens others.

Is there any way to go about this? Is it possible to make the 8's a mid-bass driver? What should my crossover settings be for this approach on both the mid-bass and bass subs?

I currently have an RE SX12, and two Diamond Audio 8's. I don't have a problem replacing the 8" woofers with another model if this might help any.

I have about 800w RMS going to the 12", and 175w per sub going to the 8's.

Help please

Gold Member
Username: Livin_loud

Post Number: 2628
Registered: Jan-06
set your low pass filter/crossover on the amp for the frequencies you want the 8's to play, same goes with the 12...

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 4787
Registered: Jan-06
Where are the 8's installed hopefully not in the same enclosure. It is possible to run 8's and 12's together very easily and share some of the same frequency without cancellation. It is all about direction. If you are going to have your crossover points to where your 8's will dip into the frequency setting of the 12 then you will need to be phased in the same direction or you will have cancellation in that range. That is why you have some frequencies hitting and some not. You just cannot have them in the same working space as the 12 or they will fight each other during action. Polo.

Bronze Member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 92
Registered: May-05
The two 8's are in a separate enclosure behind the rear seats (this is a crew cab Frontier). They are in the same box, but with separate 0.5cf sealed chambers each.

The 12" is in a 2.0cf ported enclosure tuned to about 36hz. It's mounted on the rear seat. I've tried various orientations (firing up, back, forward) without any huge success.

It still seems as though some of the frequencies are canceling out. Some bass notes are painfully loud which is the goal, but others come out very muffled, it's very obvious there's cancellation going on.

When played separately, the 8's hit like they should with excellent SQ, as does the 12".

I'm putting in a new HU soon, so I'll have separate outputs for each amp (right now both are wired to the same HU output in parallel) in case this might help any.

What would the best crossover points be? IIRC I have the 12" LPF at 80hz, and the 8's at 120hz. Since the amp's crossovers are LPF, it will play at anything below that, ultimately playing the 8's at many of the same frequencies as the 12". I don't see any way around this.

I'm sorry this post goes on and on, but all the help is greatly appreciated.
« Previous Thread Next Thread »

Main Forums

Today's Posts

Forum Help

Follow Us