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**lunchmoney** · 08-23-2009, 06:26 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

yikes... over 100 views and no comments? Tough crowd.

I guess it ain't the most exciting build in the world, but... nuthin?

I guess I won't bother next time, unless the build is something crazy.

feel the love :rolleyes:

**waynew** · 08-23-2009, 06:33 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Lunchmoney,

It's Sunday man...never post on Sunday! Should look pretty sweet when all is said and done. I am just finishing up a cabinet for CurtC's Mavericks, that have the same overall look...just a tad bigger, and 7degree lay back, and it's a t-line, and it uses different drivers...but looks somewhat similar.

Your braces - - - - watch out that you don't create lots of mini ports with those. They should have openings at least twice the size as your main port otherwise...funky things man.

Good luck.

Wayne

**williamrschneider** · 08-23-2009, 06:35 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

OK, I'll bite...

I LOVE that tweeter. It's in the Zaph ZMV5 and sounds wonderful there. I'm sure that it will sound good in this build too.

For a two-way, your plan to use the bottom plate for the crossover will probably work fine. For a 3-way, it would probably be a bit small. I like the cleverness you employed in designing the bottom section.

Going for paint again, or will you try for veneer this time?

**lunchmoney** · 08-23-2009, 06:36 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by waynew View Post

Your braces - - - - watch out that you don't create lots of mini ports with those. They should have openings at least twice the size as your main port otherwise...funky things man.

Good luck.

Wayne

See? That's why I post this stuff. I need the feedback. Still a newb.

Ok, I'll redesign those braces with way bigger holes.

Thanks Wayne!

**lunchmoney** · 08-23-2009, 06:39 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by williamrschneider View Post

OK, I'll bite...

I LOVE that tweeter. It's in the Zaph ZMV5 and sounds wonderful there. I'm sure that it will sound good in this build too.

For a two-way, your plan to use the bottom plate for the crossover will probably work fine. For a 3-way, it would probably be a bit small. I like the cleverness you employed in designing the bottom section.

Going for paint again, or will you try for veneer this time?

Thanks william

Gonna go with paint again. I've got a kick-a$$ paintbooth at my disposal, and the paint is free (mix colors from leftover stuff). Gotta keep the cost down.

**tomzarbo** · 08-23-2009, 06:42 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

I like the box shape, the top and front make a 90 degree angle so you only have one angle to contend with so it would be fairly easy to build. I like that look a lot. Man, the frame on that woofer looks thick and beefy, is it a cast unit or plastic?

TomZ

**lunchmoney** · 08-23-2009, 06:59 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by tomzarbo View Post

Man, the frame on that woofer looks thick and beefy, is it a cast unit or plastic?

TomZ

Cast

**lunchmoney** · 08-23-2009, 07:00 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by waynew View Post

Your braces - - - - watch out that you don't create lots of mini ports with those. They should have openings at least twice the size as your main port otherwise...funky things man.

Good luck.

Wayne

Wayne, are saying that each hole in the braces needs to be that big? Or the area of the holes combined? If you mean combined, then I guess I'm all set. If you mean each individual hole, I'll need to change the plan.

**jonpike** · 08-23-2009, 07:28 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by lunchmoney View Post

Wayne, are saying that each hole in the braces needs to be that big? Or the area of the holes combined? If you mean combined, then I guess I'm all set. If you mean each individual hole, I'll need to change the plan.

You basically want to minimize the amount of brace, and have the holes as big as possible, while still providing some side and cross bracing to the box walls. Ideally you want nothing in there to interfere with the airflow, and infinite strength, which of course is mutually exclusive.

Back to the real world, if your holes are smaller, you create different smaller boxes connected with really short ports. So making them rather large gets that effect below the noticeable level. I'd be thinking 1" thick members and the rest cutout, for that size box.

Another thing, make the braces like the shape of a window, rather than an X, so the wood in the middle will go from center side to center side, rather than from corner to corner as you have it now. That will make it a much stiffer support to the centers of the box sides. (wood in compression/tension rather than bending lengthwise)

**johngalt47** · 08-23-2009, 07:48 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

I built the sealed version and they are very good, especially for the price.

**lunchmoney** · 08-23-2009, 07:57 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Okay, here is is with redesigned braces... (oops, port not shown)

My first thought was "doesn't look as strong" since there's nothing going across... and I'm sure it isn't, but I'll bet it's more than strong enough... it sure worked for the Romans...

**Face** · 08-23-2009, 08:10 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

A semi-circle and a circle aren't the same thing.

**lunchmoney** · 08-23-2009, 08:19 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Originally posted by Face View Post

A semi-circle and a circle aren't the same thing.

They do, however, follow the very same basic principles of structure.

The previous solution (the original x-braces I had in there) only had 1" wide elements... and I suppose they were too restrictive in terms of airflow...

So I think this is a good solution for adding rigidity while still maintaining good airflow.

**gregrueff** · 08-23-2009, 09:23 PM

Re: Build Thread: jkim's "Poor Mans": SB/Vifa TM

Gosh, I post so infrequently now.
And for some reason only in your threads.

Maybe because you post such pretty pictures. ;)

As touched upon by others, the panel vibrations, however slight of course, are going to originate and be worst at the point of least constraint- in the middle. That is where the greatest deflection is going to be, and like a speaker cone with more xmax or driven to greater displacement, achieve greater output in the form of cabinet coloration. Therefor, I would place your brace attachment points nearer to the center of the panel, instead of the corners which are already much stronger inherently. If I remember correctly, like you did on your SR-71s.

For a brace to act as a port and impart some transfer function upon the sound might require that the length in question be longer to support such a resonance. This was pointed out to me when I brought up the same concern here some time ago. However, I believe Roman experienced detriment when he tried to connect two chambers in a system by a narrow passageway behind his midrange enclosure and reported how he redesigned the whole thing because the bass response was not acting predictably. I personally suspect this was because the passageway was long and did support a resonance. At the same time, if window braces didn't work, we would have seen it by now from the more studious measurement people- I would think.

Cheers.

Greg

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