The Joudas project

[rpb]

I would cross the tweeter higher. I have no experience with it, but, I'd target 4th order at 1.7k as a starting point. Even that might be too low, depending on how loud you want to play music. Like the woofer, the tweeter has to move, and it has excursion limits.

[trevordj]

I would cross the tweeter higher. I have no experience with it, but, I'd target 4th order at 1.7k as a starting point. Even that might be too low, depending on how loud you want to play music. Like the woofer, the tweeter has to move, and it has excursion limits.

Thank you! I chose the crossover point based on this thread: http://techtalk.parts-express.com/fo...xt25-in-seos-8

Pete Schumacher stated that, in the waveguide, the tweeter looked good to 1500hz, maybe 1200hz. I am at about 1300hz acoustic crossover point and about 1700hz electrical. I will play with it and see if I can get it higher.

[Wolf]

The second one above looks like an 800Hz xover, please don't do that...
Wolf

[trevordj]

I would cross the tweeter higher. I have no experience with it, but, I'd target 4th order at 1.7k as a starting point. Even that might be too low, depending on how loud you want to play music. Like the woofer, the tweeter has to move, and it has excursion limits.

How about this one? I struggle with phase alignment at this crossover point and, with the higher crossover point, there is a significant directivity mismatch at the crossover point.

[trevordj]

The second one above looks like an 800Hz xover, please don't do that...
Wolf

Thanks Wolf, what do you think about the first one in that same post vs. the one posted above?

[Wolf]

The first in #91 looks better to me, in terms of FR, alignment, etc.
Not sure how the tweeter will handle it though. I'd take HD measurements of it in the horn at the level you intend for and see what it does.

Wolf

[rpb]

Can you add a target in your sim software?

[trevordj]

The first in #91 looks better to me, in terms of FR, alignment, etc.
Not sure how the tweeter will handle it though. I'd take HD measurements of it in the horn at the level you intend for and see what it does.

Wolf

I'm not sure if this will suffice or if I need to run a particular protocol for this, but here is the distortion tracing from one of my sweeps. At the crossover point of 1300Hz, 2nd order harmonic distortion is at just under 1%, 3rd order at 0.24%. That's at just under 90dB which is probably right around where we will set the limit for my son.

[trevordj]

Can you add a target in your sim software?

I can, I haven't done it yet so I am not 100% sure how. Is there are particular target curve I should be shooting for?

[Wolf]

According to that plot, with applied xover as you have it, you should likely be fine.
Wolf

[trevordj]

According to that plot, with applied xover as you have it, you should likely be fine.
Wolf

What do you shoot for in terms of distortion at/around the crossover point that you consider acceptable?

[rpb]

Here's a suggestion... On the tweeter padding. Start with two 6 ohm resistors. One in series, and one in parallel. If more padding is needed, add it before the xo.

[rpb]

I can, I haven't done it yet so I am not 100% sure how. Is there are particular target curve I should be shooting for?

Let me see if I can post a picture.

This is LR4 at 1.7k. Notice that the shape of the curves match closely, and are smooth. Both drivers should be 6dB down at the xo frequency.

[trevordj]

Here's a suggestion... On the tweeter padding. Start with two 6 ohm resistors. One in series, and one in parallel. If more padding is needed, add it before the xo.

That's cool, I tried that with a couple of these and it looks good. I think these are my #1 and #2 right now. I may translate these to purchasable components and just order them and see how it goes.

[rpb]

I'd drop the notch that uses the 10mH coil. You are loosing too much sensitivity. Whatever the woofer response is at 300hz would be my approximate target sensitivity.