Almost ready to start building

[johnaec]

Giskard - do you think there is merit in starting with active crossovers to get an idea what works best? I've got two I can try - a JBL DSC260A and DBX Driverack 260. They both offer multiple slopes and crossover frequencies, though both are only stereo 3-way. Obviously I'll have to use a combination to get 4-way.

My biggest concern there is that while I do have 4 Crest amps to work with, they're all significantly different models - I'd have to look into adjusting them all for the same sensitivity. I think I know someone who can help me out in that - maybe that's the way to start.

Assuming I get all the amps/crossovers adjusted to my liking, is it a fairly straightforward response translating the padding, frequencies, and slopes over to a passive interpretation?

John

[4313B]

Well that would be cheating but it could be fun

[boputnam]

Hey, John...

Dreaming of you very cool project, the 2105H or 104H-2 subenclosure came to mind.

Make sure you leave sufficient space on the baffle for this - the tube I used is 6-inch diameter, and so has a footprint larger than the 2105H or 104H-2. This impacts the spacing of the 2405, and other (L-pads, duct, etc.).

I had great success with this stuff - it's very heavy cardboard cement form. I have plenty left, I believe, stashed in the attic. You live not so far away so I'd be happy to give enough to you if you go this route.

[boputnam]

This shows the minimum spacing required between the LE5-9 (in this case) and the 075. We swapped-in the 2405, too - identical. There was only a few mm between the UHF frame and the subenclosure.

[johnaec]

Interesting stuff, Bo. At least for my test rig I was thinking more in terms of boxes, so I could stack them however I want. But you did remind me JBL does something similar in their cabinets - maybe I'll do that for the final versions. I'm guessing internal reflections of the 2105/LE series aren't significant enough for different dimensions?

Put some 2405's in those cabinets you posted and 'looks like you'd have a set of homemade L65's, (discounting the LE14 in one of them and white cone in the other...).

John

[boputnam]

Exactly. But, my boy preferred the "look" of the 075's, so that's how we went. We had both options. From cosmetic perspective only, I couldn't steer him differently either - I LOVE the look of those 075's!

With the help of Giskard, and input from GordonW (maybe good ol' EarlK too... ) we sourced the tube and design dimensions. As well, Giskard reminded the rear surface of the subenclosure (1/2-in ply in this case) was set purposefully non-parallel to the baffle. And, that the subenclosure was not centered on the driver, either.

I'm certain all would apply to the 2105 - being Pro versions.

(ps: Nice JBL Blue, huh?)

[Ian Mackenzie]

Since you have a nice active crossover I would be inclined to mockup your drivers layout in stacked boxes , dial in the network and just listen to it before settling on a baffle or driver line up.

The 2105/077 thing is a bit of an issue and the 2105 is peaky up there and neither it nor the 077 is ideal in that scenario. Better a 066 or 044 crossed over lower with steep slopes. Although smoother this won't have the power handling your after to match the subs.

On home theatre your going to need some horn loading up there and controlled directivity is the in thing.

Have you though about the mini bi radial from the 4435 or the bigger 4430. Having heard Rob's system I would say its very nice and would be easier to get it right imho. Also the tried and proven 2307/2308, you will be surprise and the 2420's a quite cheap S/H

Ian

Ian

[johnaec]

Originally posted by Ian Mackenzie
Have you though about the mini bi radial from the 4435 or the bigger 4430.

I would have loved tracking down either a pair of 2342's or 2344's with 2425/6 to run above the 2012H's but never seemed to be in the right place at the right time.

For this set, I'm just going to see how it works with the drivers I have. But who knows what the future may hold, (especially after reading the JBL/TAD discussion...).

John

[John]

Anyone seen him ???

[Mr. Widget]

Good to hear from you!

Widget

[4313B]

Yes! Hurry back!

[Chas]

Earl, good to know you're alive!