"Crossover Design for New Project"

[cradeldorf]

I'm jonesing for pictures now!!!! :rotfl:

[Altec Best]

@ GM, One thing I have noticed is that on the board your posts are much more technical.Therefore I get lost in translation sometimes ! In our private correspondence I understand your instructions it seems much, much, easier.And make much more headway !

WRT, Pictures they will be in a week or two as I'm having a pair of the woofers re-magged,and if they come back much improved then I will send another pair.So I won't be doing much with them until I get the woofers back or close to spec !!

Have to talk with Bill.

[Altec Best]

@GM I will be resuming my build shortly.Still waiting on the woofers to get back from GPA, but I will be working on the cabs.Installing more bracing,insulation, working on the port tubes,and running the wiring into the cabs etc.... Thanks !! :2thumbsup:

When I get the woofs back I will send the T/S specs on the re-mag.

[GM]

@ GM, One thing I have noticed is that on the board your posts are much more technical.Therefore I get lost in translation sometimes ! In our private correspondence I understand your instructions it seems much, much, easier.And make much more headway !

I do what I can, when I can, so try to cover as much 'ground' as I can on-line since I always have way more to respond to than I can deal with anymore. Unfortunately for the neophytes, this usually means a lot of research to make sense of much of it.

In private, I try to make it less challenging to understand, but it takes more time, so has its pitfalls too as folks tend to either want a response like 'right now' and/or more than I'm willing to spend time on for whatever reason.

GM

[GM]

Installing more bracing,insulation, working on the port tubes,and running the wiring into the cabs etc.... Thanks !!

I've lost track of all the details, but I'm thinking that those hefty window braces combined with the 1" plywood is sufficient, so what are you planning?

GM

[Altec Best]

I do what I can, when I can, so try to cover as much 'ground' as I can on-line since I always have way more to respond to than I can deal with anymore. Unfortunately for the neophytes, this usually means a lot of research to make sense of much of it.

In private, I try to make it less challenging to understand, but it takes more time, so has its pitfalls too as folks tend to either want a response like 'right now' and/or more than I'm willing to spend time on for whatever reason.
GM

That's fine I always said a little GM is better than "NO" GM !! And as why I will just pickup the telly and call you,I've been meaning to anyway. I'll save you a whole bunch of typing.So much easier explaining/understanding on the phone "Don't cha think" :2thumbsup: Then I can post any of the results I make in the cabs in the thread for all the good folks who maybe following.

I've lost track of all the details, but I'm thinking that those hefty window braces combined with the 1" plywood is sufficient, so what are you planning?
GM

Well I definitely want to put bracing from top to bottom,especially with the weight (Sled) on top. They are super tight right now, those window braces tighten them up tremendously not to mention all the biscuits and glue used in all the joints.

[GM]

Yeah, I'm having so many problems with 'customer no service' AT&T (three modems, two service calls and ~8 hrs total on the phone to them in the last ten days alone and still no reliable service at the speed I'm paying for) and yahoo mail now that it's 'in bed' with AT&T that I'm 'chomping at the bit' for the CLEAR service to reach my house, so I can switch to a similar priced DSL with a much higher speed and ditch the phone land line for Magic Jack or ? that will allow me cheap long distance dialing.

OK, running some hardwood closet rod from top to bottom 'through' the center of the window braces should be sufficient, then take some plywood scrap or 1x3 fir or similar boards and glue them on edge to the inside of the top, placing odd lengths in a random pattern that breaks it up into a series of different size/shaped triangles. The key here is to leave gaps between them and the boundary walls to keep 'hot spots' from being created, so if the span is say, 30", make the ridge board ~ 0.7x 30 = ~21" and just 'eyeball' position it offset a bit to further randomize the panel's break-up modes.

Ideally, no screws or other fastener more substantial than an air staple should ever be used since they weaken the joint.

Note that this much attention to cab construction/bracing detail is normally complete overkill in a HIFI/HT app, especially for high aspect ratio cabs unless it's constructed with MDF or thin plywood, but I present it as a design goal for extreme situations such as stiffening up a 210/211 type cab and/or a large prosound cab/horn where there's various 'handling' considerations.

GM

[Altec Best]

OK i will check out what i can do with that.Large dowel rod for the center post.Does size rod matter I would like to use something beefy 1 1/2" - 2" rod.Would that be OK. Thanks !

[GM]

Think about what you're wanting it to do, not bow under pressure, so if suspended between two points, how much weight can you suspend at its midpoint to cause any obvious deflection? I can't deflect a 1.25" dia. x ~35" long closet rod by suspending my ~200 lbs from it, so with that in mind.............

.........take the weight of the heaviest dual driver tar damped horn and 'mount' it to the top of the cab. It's mounted via three widely spaced points in a triangular pattern, so its weight is distributed over a wide area. Calculate it and divide the horn's weight into it to find how much is centered on each sq. in. of unit area and I imagine that you can probably get by with a fairly small dowel.

If a sled is used, then there's an additional stiffness component due to increasing thickness to further decrease the required dowel stiffness (area).

If you want 'big' just for 'bragging rights'/whatever, then skip 'wimpy' hardwoods and bond in steel or cast iron pipe packed full of fiberglass insulation.

GM

[Altec Best]

If you want 'big' just for 'bragging rights'/whatever, then skip 'wimpy' hardwoods and bond in steel or cast iron pipe packed full of fiberglass insulation.

Bragging rights ? I just want it to sound good !

Correction I just want it to sound Great !