ohms and xovers

[2500hd]

Hi everyone, I have a question about this xover: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=269-148 . I'm wondering what frequency the xover will happen at if the speakers I use are 4 ohms (all of em). Thanks

[Wolf]

Off the shelf xovers are not the best route for getting the best results, but since you asked;
If you use a 8 ohm xover for the 4 ohm drivers, and it's higher than a 1st order slope, it will change the Q of the filter, and rolloff harder at the knee of the driver's slope. This can be beneficial if you want a higher damped transition between drivers if the driver has an inherent peak in the FR.

If it's a 6dB HP or LP, then the xover frequency will double or halve depending on which impedance the driver is. For a 4 ohm load on an 8 ohm intended; In a LP, your xover will rolloff lower in freq. If it's a HP, it will rolloff at double the frequency for the halved impedance.

If you use a 4 ohm driver on both of the 8 ohm intended xover positions you will create a hole in the transition between the units.

Later,
Wolf

[2500hd]

Ok thanks Wolf!

So now I have a new question: is there a way to bridge a dvc sub to the xover?

The marcato xover I have has 2 inputs that power 2 outputs for subs and 2 outputs for satellites. The sub is LP crossed @ 120hz 12db, the satellites Hp @300hz 6db/octave. The problem I'm having is my sub is dual 4 ohm, so now I'm guessing I have a 24db slope. I would like to wire the sub to be an 8 ohm load, and then bridge it to the xover so that it gets power from both channels while remaining at a 12db slope.

Feasible?

[Wolf]

Ok thanks Wolf!

So now I have a new question: is there a way to bridge a dvc sub to the xover?

The marcato xover I have has 2 inputs that power 2 outputs for subs and 2 outputs for satellites. The sub is LP crossed @ 120hz 12db, the satellites Hp @300hz 6db/octave. The problem I'm having is my sub is dual 4 ohm, so now I'm guessing I have a 24db slope. I would like to wire the sub to be an 8 ohm load, and then bridge it to the xover so that it gets power from both channels while remaining at a 12db slope.

Feasible?

You misunderstood me. The slope does not change. If it's inherently 6dB or whatever, it will not change. The frequency where it starts might change in 6dB slopes, but not in a 12dB+ slope consideration.

The DVC you have will have to be series wired for 8 ohms on one channel to keep your amp stable (if that is why you want 8 ohms), or suffice to a lower Q and 12dB rolloff with a 4 ohm load on each channel in the sub xover.

You cannot combine 2 channels without a summing network.

Later,
Wolf