4x8" speaker cab - anyone tried/built one?

[brewdude]

Thanks Cantplay. I see now.

Thanks ER. In the post with the graph, does total baffle mean width + 2 x depth (20+10+10=40). Which Hill are you just over?

[ER]

Hey brewdude-

The total baffle width ends up being the path the sound wave takes from the front of the speaker to the same point in the back in any given direction. The way the noise canceling headphones work is that they introduce the outside sound to the ear but reverse phase, it's the same thing from the front to the back of the speaker, like waves in the bathtub sound waves can cancel each other out if the phase is reversed. For a given frequency you want to avoid that cancellation in order for the note to be "there".

It's kinda weird to think about but after messing around with open baffle speakers of various widths and adding "wings" on the back it started making sense. The ultimate enclosure for a driver to do it's thing is the "infinite baffle", no cabinet reflection or port noise, but not very practical.

I'm in Sonoma Valley (Kenwood), I may be getting over the hill in other ways too I guess...

[brewdude]

If I understand you and the graph, a 10" deep cabinet would need to be 30" wide to get 40" from the center of the speaker to the edge of the cab (15") + 10" width + 15" to the center of the back in order to produce down to 80Hz.

Am I still confused?... It seemed that you were using the entire front (20") and then the width of each side (10"+10") to get the 40 inches to satisfy the frequency requirements.

I apologize if I seem a little dense. Sometimes it takes a while to sink in.

[ER]

20" with 10" depth would be ~the same as 10+10+10+10. And think of the sound wave as spherical. Then there's other weird stuff to consider like radiation patterns into infinite space, half space, quarter space, etc.

An amp sitting on the floor would be half space, on the floor next to a wall quarter space, on the floor in a corner eighth space and so on. That's why you can get away with a slightly smaller cabinet in practice than just the speed of sound math. Think of that sphere getting sliced up by different planes.

Low frequencies are long waves, higher are short. That's why a speaker out side it's cabinet still has the highs but no lows. Put on the floor you hear a little more lows against the wall a little more in a corner more still and so on.

[Geeze]

You guys really disappoint me. I half hoped for reasoned and rational comments to 'RUN AWAY - HERE BE DRAGONS!' But no, for the most part the replies are only fanning the flames of desire.

Statorvane asked about 2x10's. I built one and it got the smaller yet toneful boulder rolling down hill. 15" square and sounds tight and controlled at volume.

I will be wood shopping this weekend and will acquire a pair of the WGS 8" and at a later date something contrasting.

[rp]

You guys really disappoint me. I half hoped for reasoned and rational comments to 'RUN AWAY - HERE BE DRAGONS!'

We are waiting for you to build it and post that you have 4 8" for sale I'm sure it'll be pretty cool, especially the low efficiency which is useful to have. If I had extra dough burning a hole in my pocket I'd build one too, can never have enough amp stuff around.

Report back on the WGS 8"s.

When you sell off the WGS I'll be in line for one

[Geeze]

Ah HA! Now I see your nefarious plan. No luck on wood as I didn't see anything at Wood World so I will probably retro fix a 2x12 cab for the first test.

An earlier post mentioned the Eminence 8, I wish they made them in 8 ohm, I'd buy a couple in a heart beat. Very interested in the hemp cone thing.

I will get 2 WGS and will be looking at either the Weber or the Jensen series for a contrasting tone as they both build 8 ohm 8's.

[rp]

An earlier post mentioned the Eminence 8, I wish they made them in 8 ohm, I'd buy a couple in a heart beat. Very interested in the hemp cone thing.

Those are hemp? You'd think they'd be too stiff for something of such small diameter.

For open back I'd use pine for 8s to get a little more bass (actually boom as it's not really bass extension) but the warmth might be needed. Nothing thicker than 1/2 for the baffle, maybe less if real small cab? I don't like pine closed backs as they can really boom, but a pole btwn baffle and back can help. If closed I would put a tee nut in the middle of the baffle before grill clothing, that way you have the option to use a 1" dowel with a hanger bolt screwed into it to easily add a brace. Glue a ~3"sq, 1/2 thick scrap to the middle of the back with a 1" hole drilled out to help you line up the brace when closing it up and screwing it together.

Now you got me thinking of a 4x8 5F1 Champ combo... That'd be some goofy fun. Some harp guy must have done it.

[Geeze]

Put the two 8" WGS into my 2x12 Frankencab and was amazed by the punchy authority. So full speed ahead into the 8 unknown [yeah, I couldn't help it]. I purchased two of the Weber Chicago ceramics last week and started cutting the baffle parts. Went to Lowes for the screws and more clamps and came home with popular and have constructed the 20x20" shell.

[Geeze]

Corners now rounded, back cut and drilled. Baffle sanded and painted. Boo boos cussed, sanded/filled or ignored. The finish will be oil. Looking into external handles or routed drawer pull styles. May just use a top handle as I expect it to weigh in the low 20lb range.

Weber said a couple of weeks on speakers and I am waiting at top speed.

[Cantplay]

Looking good. The edge band sets it off nicely.

I go through the poplar rack and grab the highly spalted boards. I like the colorful high contrast.

You could cut through slots fot handles, and cover them inside with a small box.

John

[statorvane]

A 20 lb slant cab - nice idea - the Mini Me of the half stacks!

Really good looking - that's going to come out nice.

[Geeze]

I cut handle slots with a box inside on a 2x12 slant cab and while they work fine they look so so. I thought for a next build I would rim them with the contrasting wood. Then the 'mini' bug bit.

For this one it occurred to me that it would weigh about 20lb and why not use a top handle? Salt and pepper jute grill cloth and a Mesa style 'leather' handle are coming from Lopoline this week.

Needless to say the cherry and walnut planks sitting in the shop are calling loudly to be used.

[Mark]

You will have to post audio on how it sounds, a comparison with 12" speakers would be good as they are a good standard.

[Geeze]

I tried last night with a marginal mic that refused to work - probably for the best. Any recommendations on mics that can run via usb and not break the buy speaker bank?