Simplex 112. Ooops. A big deal?

[crockettnj]

I have been away from the nuts and bolts of music and cab building and messing around for a while.

As luck has it, I once again have access to a shop as well as a new band.

OK so I pulled some gear out of storage, dusted off the BFM Simplex, OMni 10, and Jack plans, and decided to buiild a simplex.

I have all sorts of spare random parts that I've squirreled away over the years sitting in a box, along with a bunch of brand new and used 3012HO drivers.

So I am assembling a Simplex 112 and nearing the end. Its going very fast. Great plans, nice well thought out build.

I came to the back and didnt have the plans with me. So I made some guesses from memory, only I was wrong. I guessed that the back panel was inset and screwed into strips. As you are likely aware, thats not the case. The back panel isnt flush mount, it fits over the sides/bottom'/top panels.

. Coupled with this, I am using handles I stole from some old PA cab, and they stick into the cabinet a fair bit more than what one would normally expect.

So, I did some rough math and my cabinet volume is reduced by 200 - 250 in^3. Thats right around 5%.

Audible? Meaningful? Based on previous 'experiments' with cab building, I am guessing that its no biggie and wont be audible.


Should I both adjusting the ports or just leave it alone? I havent mounted the driver and wont be able to until mid week next week, so I figured I'd ask here first.

Thanks to the crew here in advance.

[crockettnj]

Zilch on the replies. I am surprised.

I decided to build a 2nd simplex112 since i have another 3012ho driver and most of the lumber.


My decision is to leave the 'oops' back on cab 1 alone and to compare the 2 cabs to one another when complete.

[Seth]

Wish I could help.

Bill?

[Bill Fitzmaurice]

It won't make a huge difference.

[crockettnj]

... OK I had a chance to mess around with the cab and its sibbling.

Both are simplexx 112 loaded with a 3012HO. Piezo tweeter temporarily installed until I get the correct tweeter and xover.


I did the dancing sawdust/sand test on them, using a 25watt poweramp and an online tone generated. The first cab, referenced in the original post, looks to be tuned to 41 or 42 hz. The second cab, correct dimensions, shows 42 or 43. So, two things. Neither is 45 hz, and the smaller one is tuned a skootch lower.

I didnt adjust either one to 45 hz, opting to leave it alone for my gig and them mess with it when I do the duratex.

On aside note, the second cab sounded horrible. Farted out on low volume, and was unusable @ higher volumes.

After scome head scratching and testing, I learned that the driver frame was touching the side of the baffle. The little nailers on the baffle for each screw was a bit proud, and it caused all heck to turn loose.

Additionally, there was some air escaping from the driver gasket. I added some weather stripping stuff, which rectified it.

Lastly, despite being connected visually correctly, the 2nd cab was out of phoase with the first. Not sure how. It was rectified once I switched the polarity @ the driver. Not sure how or why, as I have used all of these cables etc before and they are wired correctly. Can a driver just be out of phase? This is a first for me.

They rocked nicely on the gig tonight. I will continue with the xover and appropriate horn on one cab, and maybe go NT on the other. it needs a good roll of duratex too.