The Amp Garage

Posted: **Wed Oct 14, 2015 8:09 pm**

My 2 cents worth...excursion is important with bass cabinets, and possible downtuned guitars...no experience there.

That Standell is brilliant. Never saw that type before.

I wanted to build a bass cab once and I was advised to do what Carvin has done. Find a good sounding cab and copy it. I copied an Aguilar GS112. I didn't get the Foster horn, fwiw. It's my standby.

Posted: **Wed Oct 21, 2015 8:20 pm**

Colossal wrote:Also, can you speak to the geometry of the port area? Should it be round like the speaker cutout or can it be other shapes so long as the port area is equivalent to the speaker area?

Any shape roughly equivalent to the speaker area. "Roughly" can be very rough. There's been no real rigorous analysis behind this that I can tell, it just sounds good to have big holes in a really big closed-back cabinet.

Posted: **Wed Oct 21, 2015 9:39 pm**

Cool, thanks Shoggoth.

Posted: **Thu Oct 22, 2015 12:43 am**

I agree that a lot of those grail combos and cabs like the 1960 Marshall 412 cabs were happy accidents.
Not much attention was paid to the actual speaker cabinet on early amps.

I have had speaker cabs that sounded like arse no matter what I put in them....

And a couple that seem to sound pretty good no matter what I subject them to.

I think I briefly experimented with detuned cabs as far as leaving a speaker hole empty and don't remember any grand revelations.

Posted: **Tue Jan 30, 2018 7:05 pm**

Are there any phase cancellation issue?
Because it allows the phase cancellation from the front hole which is normally blocked by the closed baffle.

Posted: **Tue Jan 30, 2018 9:18 pm**

There's no phase cancel issues but on thing I found out after building four detuned cabs was if you make the ports too small you're guitar will sound like a bass and you'll shake the walls, windows, and anything not nailed down in the house....

Posted: **Tue Jan 30, 2018 10:09 pm**

tictac wrote: ↑Tue Jan 30, 2018 9:18 pm There's no phase cancel issues but on thing I found out after building four detuned cabs was if you make the ports too small you're guitar will sound like a bass and you'll shake the walls, windows, and anything not nailed down in the house....

Tictac,

Would you mind elaborating on your detuned cabinet dimensions and port sizes a little? I'm quite interested.

Posted: **Wed Jan 31, 2018 12:42 am**

Sorry don't have the exact dimensions and I don't have these cabinets anymore but if I recall correctly they were around 11.5" to 12" deep. Ther amphead on top was about 23" wide and would sit suggly on the top some I'm thinking they were ~24" wide. Two of the cabs have 15" JBL's and two have 12" EV12L's which may give you an idea of the scale. As you can see the ports are pretty substantial. I built the 15"s first an had to widen the ports. They were shaking the house apart even with the bass control turned all the way down.
On sevreal occasions I used these cabs as a PA system with mics and acoustic guitars and I thought it performed pretty well. The real purpose for this wall of sound was for the SSS type amp I had built. It was like Dave Roots SSS, no reverb. My was stereo however and boy did it sound glorious with the four of these cabs singing away

Problem was they are SO HEAVY! Baltic birch ply is beautiful but not light weight. I finally let them go on Craigslist and a fellow took all four, (without speakers)

TT

Posted: **Wed Jan 31, 2018 1:20 am**

tictac wrote: ↑Wed Jan 31, 2018 12:42 am

Sorry don't have the exact dimensions and I don't have these cabinets anymore but if I recall correctly they were around 11.5" to 12" deep. Ther amphead on top was about 23" wide and would sit suggly on the top some I'm thinking they were ~24" wide. Two of the cabs have 15" JBL's and two have 12" EV12L's which may give you an idea of the scale. As you can see the ports are pretty substantial. I built the 15"s first an had to widen the ports. They were shaking the house apart even with the bass control turned all the way down.
On sevreal occasions I used these cabs as a PA system with mics and acoustic guitars and I thought it performed pretty well. The real purpose for this wall of sound was for the SSS type amp I had built. It was like Dave Roots SSS, no reverb. My was stereo however and boy did it sound glorious with the four of these cabs singing away
Problem was they are SO HEAVY! Baltic birch ply is beautiful but not light weight. I finally let them go on Craigslist and a fellow took all four, (without speakers)

TT

TT,

Thanks for the report! That looks like a killer setup and I bet it was incredible running in stereo like that. Talk about air and 3D presence

The thing that interests me about the detuned design is the big sound-from-everywhere-at-once response. The massive low end is a plus (although I guess there can be too much of a good thing).

Thanks again.

Posted: **Wed Jan 31, 2018 11:34 am**

dumb question...

why is always the woofer (port) positioned below the mid freq speaker? and why tweeter above the mid?
in other words, i wonder why there is the "detuned" hole below the speaker in the below cab?

Posted: **Sat Feb 03, 2018 2:56 am**

idnotbe wrote: ↑Wed Jan 31, 2018 11:34 am dumb question...

why is always the woofer (port) positioned below the mid freq speaker? and why tweeter above the mid?
in other words, i wonder why there is the "detuned" hole below the speaker in the below cab?

Generally, betterl dispersion of highs in the front rows by getting the tweet or squaker closer to ear level.

Posted: **Sun Feb 11, 2018 4:24 pm**

The 'woofers' [if a crossover is used to separate the freqs] or low frequency from the speakers use the floor and or walls as an extension of the speaker's 'horn' to help develop the low end wave forms - many can be measured in feet. In the 40's Paul Klipsch produced his Klipschorn that sat in the corner of the room and used both walls [the bass was ported to the sides of the speaker - not the front] and floor as an extension of its horn. Monster freaking HiFi speakers.

Russ

Posted: **Sun Feb 11, 2018 8:22 pm**

I have an old Peavey Speaker building manual which contains pages of different types of cabinets for Sound Reinforcement and has a lot of data as well.

I've made floor monitors and PA cabinets from my Peavey manual years ago when I was too broke to buy expensive gear.

Mark

Posted: **Fri Feb 23, 2018 10:20 am**

I have wondered about these cabs too. KOC has a couple of different speakerbox designs. There is the 2X12" cab with the missing speaker, the 2X12" cab with the front ports (don't rely on KOC drawings as they aren't drawn to scale, draw the speakerbox out for yourself), and the 4X12" cab with the port at the bottom. These cabs must surely sound different from one another?

Has anyone built more than one type of KOC speaker box. The other question is why aren't these boxes more popular,

The Amp Garage

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