BillFitzmaurice.info

I've PL'd wires out the side of my ATs before and it was fine. Messy and not pretty looking, but it worked. It was temporary till the speakons and binding post arrived.

Ok, now I need some help....

Got the crossover wired inside the cab. Hooked everything up just to test and ran some music through it. Speaker was just sitting in the sub and it's still missing one side.....I noticed that I was hearing a lot of higher end material out of the sub driver.

So, I unplugged the top box to check it out.....ran a 1k test tone through it and was hearing it....ran a 4k tone through it....hearing that too. When I plugged the top box back in, of course that box reproduced both tones much louder.

I've always run my subs through a 24db/octave slope crossover, so I've never experienced hearing the higher stuff though a sub. The T24 passive crossover is as per the plans. The plans say the high pass is 6db/octave slope, but it doesn't address the slope on the low pass.

Does it have a really low db/octave slope on the low pass? Is that why I'm hearing 1k and 4 k out of it?

I don't see how it could be wired wrong.....it's very simple. Just put the inductor in series with the driver....not much to screw up there.

Bill or Leland.....any ideas? Should it be like this since it's passive?

Need to figure it out before I button it up.

Even if you are getting hi end frequencies through, will they not be filtered out by the horn?

It's a first order 6db. You will stilll hear higher frequencies , albeit at lower and lower volumes. The xover point is 150hz iirc, so 1k will only be about 4-5 db down.

LelandCrooks wrote:It's a first order 6db. You will stilll hear higher frequencies , albeit at lower and lower volumes. The xover point is 150hz iirc, so 1k will only be about 4-5 db down.

Thanks Leland. I kinda' figured that was the case. So, I guess I'm gonna' be pulling a wide swath of EQ centered around 150 to clean out the mud in that area....with two sources playing there.

LelandCrooks wrote:It's a first order 6db. You will stilll hear higher frequencies , albeit at lower and lower volumes. The xover point is 150hz iirc, so 1k will only be about 4-5 db down.

Ok....so, what's the reasoning in using such a shallow slope for the crossover? I'm sure it would require more components to go steeper....what would that look like?

I wonder if surgeons feel a little reluctant about closing after working on somebody's plumbing......I mean, why are we closing up the cool stuff where nobody can see it?

Last look before the side goes on.

Looking good, Bruce.
What are the four plates for?

Bruce Weldy wrote:
Ok....so, what's the reasoning in using such a shallow slope for the crossover?

$$$$$$

Bruce Weldy wrote:I'm sure it would require more components to go steeper....what would that look like?

You would need 2 of these:

and then 2 of these:

that's over $130 for a 12 dB/octave x-over @ 120hz.

CoronaOperator wrote:

Bruce Weldy wrote:
Ok....so, what's the reasoning in using such a shallow slope for the crossover?

$$$$$$

Bruce Weldy wrote:I'm sure it would require more components to go steeper....what would that look like?

You would need 2 of these:

and then 2 of these:

that's over $130 for a 12 dB/octave x-over @ 120hz.

Yikes!

Ok, I guess the crossover does indeed fit in the driver chamber....but it was way easier to get it in before putting on the other side.

Chris_Allen wrote:Even if you are getting hi end frequencies through, will they not be filtered out by the horn?

Those with more knowledge can correct me if I'm wrong, but the horn doesn't filter high frequencies per se, but rather harmonics of the root. In this case, it's the root that's coming through, not harmonics.

Tom Smit wrote:Looking good, Bruce.
What are the four plates for?

As I stand over six feet tall and bending over isn't one of my favorite activities, the idea of tilt-back casters on a two foot tall cabinet is far from appealing.

So, I'm putting four casters on the bottom and I will roll the little darlin' to her proper position.....I may even sit on her to rest my aching back.

If this experiment works out the way I want, it will reside in my garage as my stereo...(albeit in mono) when it's not pounding unsuspecting drummers into sonic nirvana. Most drummers around here don't get any kind of monitor - now they will have the best one on the stage.

Bruce Weldy wrote: Ok....so, what's the reasoning in using such a shallow slope for the crossover? I'm sure it would require more components to go steeper....what would that look like?

$$$$$. A high quality 18dB 2-way passive crossover at 150Hz or lower would cost more than an active crossover. That's why they're not used. The 6dB crossover in the plans is a better than nothing option.

Those with more knowledge can correct me if I'm wrong, but the horn doesn't filter high frequencies per se, but rather harmonics of the root. In this case, it's the root that's coming through, not harmonics.

The horn filters high frequencies. It neither knows nor cares if they're fundamentals or harmonics.

Bill Fitzmaurice wrote:The horn filters high frequencies. It neither knows nor cares if they're fundamentals or harmonics.

Then I learned something. So, I'm assuming that the 4k I heard coming out of the speaker itself will be greatly attenuated when coming out of the horn?

That would indeed be a good thing.

Thanks for another lesson.

And mea culpa to Chris - you were right.