A few PE Dayton 3-way crossover questions...

[ptwining]

The PE crossover I am using (until I learn enough to build my own) has an 8 ohm and a 4 ohm setting for the woofer cross at 700Hz.

I am running two Dayton 10" reference series woofers. As I understand it the amp will see the sum of the two 8 ohm drivers in series as a 4 ohm load anyway.

What advantage (or problem) will I get if I simply leave the XO set at 8 ohms and let the amp carry the load?

Should I change it to 4 ohms and if I do won't the amp see a 2 ohm load?

I really don't notice much sonic difference if I change the setting to 4 ohms on the XO, should I?

The PE XO seems to EAT power by the way. Should it?

Regards,
Tom

[Cal Weldon]

Hi Tom,

This is a very basic description of XO's and your questions.

1. The premade XO assumes an impedance of 4 or 8 ohms. This will not be the actual measurement of the impedance so the XO point will be a little different than 700 Hz.

2. Running the two woofers in series will result in a 16 ohm load not 4. To get 4 you need to parallel them. Again this is a nominal rating and not actual so the XO point will not be exactly 700 Hz.

3. If you parallel them (4 ohm) and leave the switch set to 8 ohm, your XO point will change. Always match the impedances. For example to get a 700 Hz XO point with a first order at 8 ohm, you need an inductor of around 1.8 mH. To achieve the same XO point with a 4 ohm driver you need only a 0.9 mH. So you see that everytime you double the impedance you need to double the value of the inductor. Same idea with the caps.

4. The impedance of the XO is not 4 ohms. The rating is to determine the XO point. It is what the XO wants to see in order to achieve the intended XO point.

5. The more you listen the speaker, the more difference you will notice. If you wish to hear more of a difference, try unhooking the tweeter and mid and leave just the woofer. That will be more noticeable.

6. XO's will eat some of the power. This is kind of "lost" iin the windings and resistors. The more components in the XO, the greater the loss. This is normal.

As mentioned this is rather basic but hopefully it will give you a better understanding.

[ptwining]

Cal,

Okay.

First, where will the crossover point move - up or down?

Second, If I have, for example, one cabinet (divided into two chambers but that's not relevent to this question) and I am :

running two 8 ohm full rangers up top - in parallel

AND

two 8 ohm woofers in the bottom - in parallel

Do I get an overall 2 ohm load?

or does the amp see a four ohm load?

Do I sum the drivers as a group, or not.

Jeez, I feel like an idiot but it isn't clear to me...

Thanks for the help...

Regards,
Tom