GK Build-Your-Own-Combo : Porting Questions

[whyachi]

I'm no amp designer, and I'm really not good at 3D, so the 18" downward-firing woofer is probably ridiculous, but I think it looks cool anyways. The texture is cherry wood, to match a bass I also made. Just used Google Sketchup, since its free. It's all to scale, minus the knobs on the 700RB as I couldn't find a good photo to measure.

http://i45.tinypic.com/zjyz5f.jpg
http://i48.tinypic.com/2eb68n8.jpg
http://i49.tinypic.com/2ijjket.jpg
http://i45.tinypic.com/2mxtlu.jpg



Here's where the GK bit comes in,
http://i47.tinypic.com/eu1nuo.jpg
http://i50.tinypic.com/o6y908.jpg



With the cherry-necked bass I call the Insomniac Special, and no the edges aren't supposed to be square but I couldn't figure out how to fix it,
http://i45.tinypic.com/ixbdhc.jpg

 

[Super Turbo Deluxe Custom]

That's pretty cool.  I'd want some kind of grill protecting the speaker face.  It might be annoying on stage as the bass portion of the 18" speaker is projected 360 degrees.  However, those in the know with certificates from sound schools will say the waves that make up bass frequencies are so big, they're almost 360 degrees anyway.  Making the box taller by putting a scoop under it could fix that.  That is a very cool idea though.

On a side note.  It seems bands I've been in, the bass player's rig almost always has the largest area of flat space on top making it the stage's coffee table.  Keys, sunglasses, ashtrays, beers, picks, and sometimes sound boards (none of which were mine) have found their way to the top of my rig often with little or no discussion with me.  Making this space look more inviting would not be on my list of things to do.  I'd shape mine like a pyramid.  LOL. 

 

[whyachi]

Since I'm not one with a sound degree, can you explain what you mean about a scoop under it?

 

[Super Turbo Deluxe Custom]

I don't have a sound degree either.  A scoop is literally a "scoop."  You see them a lot on older, larger subwoofers.  It looks like one side of skateboard half-pike.  It allows for a smooth transition to focus the direction of the sound.

 

[whyachi]

I'm working on modifying the design a bit, per the suggestions from some guys at the GK forum.

 

[whyachi]

This might solve the coffee table amp syndrome, and help direct the bass a little better.

http://i45.tinypic.com/2rcabth.jpg
http://i46.tinypic.com/2qxrpk0.jpg

 

[Wana_make_a_guitar]

Thats an interesting looking design. I've no idea how it would sound but it looks cool and I think that inbuilt rack amp holder thing is a cool idea. Nice to see someone else uses Google sketchup to design amps.    :icon_thumright:

 

[Patrick from Davis]

I worked for a sub woofer company way back when.  You really want to keep the X, Y, and Z lengths of the cab different.  It tends to have odd resonances if you don't.  If it is ported, you fill it with foam or fiber (polyester quilt filling...) to keep the air from moving in and out of the cab.  The diameter of the ports and their lengths (overall volume) will have a large effect on the tuning of the cab.  In general the bigger the cab, the bass-ier it tends to sound.  Sorry I can't give you specifics on how to figure out all of the info, I didn't get to play with that kind of stuff.  Looks fun.
Patrick

 

[whyachi]

I don't have the tools or know how to build it, so its really all just a theory.

 

[blue313]

I don't have the tools or know how to build it, so its really all just a theory.

But you will someday.  Keep working that design, it's an interesting concept.

 

[whyachi]

Keep an eye out, in ten years kG amps will be hot stuff.

 

[Alfang]

I love the idea, I actually have envisioned just about that exact idea,  I would recess the smaller speakers for protection, and you would need a crossover circuit to run those speakers properly.

And I'd put the handles on the side so that it could really be an end table.

I think there's a market out there for furnature amps  ie.... looks good not designed for hauling arround giging

 

[Wana_make_a_guitar]

Have you actually made components to the cab itself or is it just textured faces? Once you start making components, the build will become easier.

 

[whyachi]

If you zoom in and rotate it around, which obviously can't be done with a .png, you'd see the only textures applied are the black pearloid logo and cherry wood. If that's what you were referring to, anyways.

I live in a little one-room apartment, so until that changes and I get a garage this thing won't be built.

 

[whyachi]

I found someone with a workshop that's willing to share. I'm going to put in some study time on speaker design and see if I can knock out a prototype by February.

From there, who knows, maybe it'll work. Is Carvin generally a good place to go for inexpensive amp parts?

 

[MUYFUE]

That's a cool design. The downward firing thang is cool too, that's how home theater subs are set-up.

An inspiration!

 

[whyachi]

I didn't bother applying textures but I think those are much more solid designs than the original.. all three would be 212 systems with a 2U rackspace for a GK 700RB-II head to bolt in. The airhead design with the rack on top is a little too standard for me but I'm having trouble deciding between the other two.. My father got ahold of my designs, and even though we haven't really spoken in years he wants to help me build it. Some kind of father.. son.. thing. Who knows. Free labor!

I took the advice I read somewhere about ports being about 1/2 the size of the speakers, so two 3" ports on each side. I figure on the side-by-side design I could build it like two seperate boxes.. that's how the big boys do it right?

The tophat handles would likely turn into simple strap handles out of necessity but I think the rest is very doable. I'm up for comments and feedback of any sort.

I was thinking 3/4" birch ply and possibly Celestion speakers if I can find( / afford) them, the green label ones for that oldschool fat rock sound.


Who knows, if they sound good I might start building them in my living room or something. Discounts to Warmothaholics, right?

 

[Super Turbo Deluxe Custom]

The Mesa Boogie "radiator" uses a downward firing sub too.  If possible, on the designs posted, I'd put the ports facing frontward.  Much of the bass will be lost unless placed right in front of a wall.

 

[whyachi]

Its possible, sure. Again, knowing nothing about amps, I figured ports are ports and liked how those look like exhaust pipes. I'll whip something up later.

 

[whyachi]

Are there differences in sound between round ports and slot ports? I'm trying to figure out which to add onto the amp design before I actually start cutting anything. Round ports would be easiest to add onto my existing design, though if there's a huge difference I could add a slot port on the side / bottom. I've seen it done all ways, from round ports on Aguilar and most other cabs to slot ports on Eden.. I've never had a chance to A/B them.

Also, is there any reason behind the rule to making your ports total half the size of the speakers? Like for a 212 cab, should I shoot for 12" total in ports?