Am I on the right track? Bookshelf speaker Fountek FW146 / Dayton DC28F

[isaeagle4031]

Your questions and your quest are point on. This thread will serve as a source of information for others starting off.

Yeah that is what Ben is referring to. What you have now is a solid base and one most people would be very happy with.

[scottvalentin]

Following this thread has confirmed my approach and steps in modelling a few TMs as well. It has been helpful and good job in persevering through all the steps. Also, to guys like Wolf, Chuck,RPB, and others, your assistance here has also helped me. So thanks a lot for your time and input even if I'm not the OP!

[WernerM]

There is so many details that need to be accounted for. I'm not discouraged at all. I feel like I'm dragging along this thread and annoy you all with all these beginner questions and confusions. :-) hope that's not the case.
If I remember correctly I have turned on the overlay in the past, but it didn't seem to show me anything different. I'll have to confirm that though. I usually flip the polarity on the tweeter briefly to so how much the reverse null dips down (I assume that is acceptable way of checking it)

Wolf when you talk about the woofer possibly ringing, are you looking at the woofer breakup starting at around 5kHz? And to try to push that even further down?

Not sure if I'll have time tonight, but will post updates by this weekend.

When you flip the polarity to see the reverse null click save sum to overlay, then when you flip the polarity back that reverse null shows up as a grey Fr curve.

[crossbound]

Thanks for the encouragement guys!

Ah that's how it's done with the reverse null. Thx

[PWR RYD]

No appologies needed Marc. You are doing great and learning a bunch along the way. A ton better than just expecting the forum members to design a speaker (crossover) for you.

Your splice at 200 Hz looks a bit funky. Other than that I agree if your bsl is close and your impedance curve is ok you have a simulated design worthy of building.

[WernerM]

I agree with Craig and Ben, this is worth a shot if the impedance is good. I was only suggesting the tweeter adjustment in case you hear any distortion. If you sim it now, you'll have the option if swapping the crossover parts if you do.

BTW Craig...

"I just keep trying to get a little better, a little better than before..."

Love Mr. Brownstone

[crossbound]

I'll definitely try to adjust the Fs down a little more and also see what I can do with the woofer break up.
The only issue I've had before when going steeper on the high pass is the phase going out of alignment and didn't know how to reign it in again.

[WernerM]

There are several ways to adjust for the phase, the easiest is with resistors, but adjusting the freq of the knee of the rolloff (crossover point) and steepness of the slope will shift it as well. As you play around you will see this. You can add a resistor to the shunt (parallel component) and that will change the angle of the slope also.

[Wolf]

There are several ways to adjust for the phase, the easiest is with resistors, but adjusting the freq of the knee of the rolloff (crossover point) and steepness of the slope will shift it as well. As you play around you will see this. You can add a resistor to the shunt (parallel component) and that will change the angle of the slope also.

Actually, adding the damping resistor will change the shape of the FR rolloff knee and it's phase (derived from FR) at that range, but the inherent slope of the rolloff won't change. Changing the order changes the slope, or some clever notch filtering will also.

Later,
Wolf

[crossbound]

Here is version 3 of my Peerless tweeter response curve. It took a little while to figure out how to get the phase aligned better. What ultimately seemed to get me closer was adding the parallel resistor over the woofer. Is the high impedance at 5kHz an issue? And is the impedance phase okay?
Thx

[Wolf]

Parallel resistor where at the woofer? Can you show the woofer circuit cells? I want to make sure what you have won't be cause for concern.

Later,
Wolf

[crossbound]

Here you go. Also I just remembered that I meant to ask where I should put the DCR value for the 1.5mH inductor in the RCL notch filter. I put the 0.22Ohm value in the L2 section. Is that the correct way of doing it?

[Wolf]

Make sure that resistor is of sufficient wattage, and I'd shoot for a 25W resistor there. If you up the resistance to 50-60 ohms the power requirement can be reduced to using a 10-15W resistor. This may not be doing what you think it's doing. All that resistor is doing is reducing the magnitude at the inductive rise and Fs of the woofer, and minimally everywhere else. I'm not sure how it can affect the phase as you say. If you want to add a resistor, try using a 0.5-4 ohm resistor from C2 to ground instead of by itself. This will shift your phase, and affect the knee at rolloff. Honestly, the FR at xover is a bit bumped up, and this may help that as well.

Later,
Wolf

[crossbound]

Actually looking at it again. you are right. It doesn't have that much impact on the phase. What it did help with is dropping the reverse null.
Also if you could look at my previous post again. I added an other image and was curious if I was placing the DCR value for the inductor in the RCL in the correct spot.

[Wolf]

That is the place you have to put it in PCD, even if it's not the best place to put it. That's how I do it, since it's about the only place you can enter it for a notch.

Later,
Wolf