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In the Forum: Horn-Loaded Speakers
In the Thread: Midrange driver suggestions
Post Subject: 4way active design conceptsPosted by homebuilder on: 1/3/2008
Romy:
Thank you for your response.  You are correct that the vision is not completely developed for this 4 way.   A bit more info is needed.  I've had some experience with JBL woofers, but am relying heavily on the results achieved by a good friend who has a 2226 ported, 2344a-2426, and 2404H sitting on top in a heavy steel framework.  3 way active. He purchased the TAD 1201s from Nelson Pass to augment this system, but never built the new cabinets.  I bought the TADs from him.

You are right on the money about the TAD...I plan to build the midbass cabinet first, and listen to it, probably with my ARC VT-130 tube amp.  That driver is amazing, but I plan to restrict it to 200/300-800/1000 range eventually.  For this, I will build a laminated constrained layer cabinet of 1-2cf sealed.  We will use threaded rod and angle iron to bolt the sections together, so we can vary the internal volume by adding or subtracting 3/4" layers; as we listen. After the volume is finalized, it will all be glued up properly.  My plan was to hold off on the 15" vs 18" JBL until the verdict is in on the TAD bottom end.  The 18" has more severe breakup than the 15" past 200hz, but goes a bit lower.  I'm also worried about midrange/tweeter height, and the 18" makes it just that much taller.

I plan to get the 2404H soon, and will start using them with the TAD 1201 as a 2 way, for awhile. All drivers will be in independent cabinets.  The bass cabinet will be 4.5-8 cf range, by the way.

An important part of this project is the woodworking aspect...I'm not in a hurry. I have waited 25 years to get my dedicated audio room, I can take time to develop the right combo.  Some of the JBl drivers such as the 2118, 2123, etc look very interesting for this aspect of the project.  I am particularly interested in ideas along those lines.  I've listened to several open baffle designs, and in general find them very appealing. I wanted to try an infinite baffle sub, but the rooms adjacent to my audio room just won't allow that.

Finally, my room has angled corners at the front, where the side walls slope down.  They could house a massively braced cabinet, if that made any sense.  The internal volumn is pretty large, could be as much as 45cf, even if sand filled
 construction was utilized to brace it all.  I have read a lot about various horn combos, but have no experience or idea of what would happen if something were built into the corners of my room.  I suspect a subwoofer would be just fine.  I am worried about the effect of the sloped ceiling.  The ridge runs front to rear along the center of the room, tapering down to sidewalls.

Thanks for your help!
Greg

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