Designing a baffle on a 2x8 cab

[merkaba22]

I bought an old GK 208LGS 2x8 all metal guitar cab from the early 90's on a lark, to see if I could get a small cab to sound good and be portable, etc. The GK cab was also interesting since I like the old 250ML II's.


I was encouraged by the Quilters, as I still use a preamp for OD, etc., and decided to upgrade from the Pyles to the Celestion TF 0818 -- when I was installing the new speakers I noticed that the metal panel that provides the baffle bends upon tightening. I remember a Scumback thread about a bend metal frame on the speaker was concerned.

So, I was pretty careful and when I fire it up, the clean sounds very nice but the OD is not there -- I wrote to drdecibel and he impressed me that the baffle is big deal.

So, I wonder if any designer can offer ideas regarding my immediate plans to cut piece of 1/2" maple to size w/ speaker holes, etc. and position it either on the other side of the speaker or sandwiched in between to get closer to a dadoed baffle rather than creating a floating baffle -- another factor is whether to front or rear mount.

The speaker screws could hold it in place, but gluing the maple to the metal might be better ....

Ideas are welcome.

 

[Geeze]

I am surprised there aren't any torque specs for mounting speakers. I tend to snug and use finger nail polish as a thread binder.

Why maple? I suspect because you have it on hand. Most baffles I've seen and built use plywood. I'd cut the wood to fit to the back side of the aluminum grill and drill a few holes / screws into the sides to hold it in place.

[my internet connection is marginal - I typed most of this before I saw the pic]

Another question - did the Pyles give OD?

Russ

 

[merkaba22]

I am surprised there aren't any torque specs for mounting speakers. I tend to snug and use finger nail polish as a thread binder.
So you're talking about a wooden ring or a plate to stiffen the aluminum? Why maple? I suspect because you have it on hand. Most baffles I've seen and built use plywood. I'd cut the wood to fit the aluminum grill and drill a few holes / screws into the sides. I have the 12" speaker version somewhere and if memory serves the grill / face plate had 1/2" or so edges bent 90 degrees to the face for stiffness. Pics would be handy if I have it wrong.

Another question - did the Pyles give OD?

Russ

I've built a few cabs and used birch baffles dadoed into maple/mahogany hardwood cabs -- I like when cabs are the same material as the instrument -- the cab, as it is now, is a bit bassey and not focused -- maple could help. Also, if I do use screws in the side, a solid wood would be better.

The Pyles were fine for OD, tho's a bit buzzy on the top and dated -- after 25 years and the Quilter I had to try these Celestions -- closer to EVM's ... who know what they would sound like with a better baffle -- I am glad I kept them

 

[merkaba22]

 

[J M Fahey]

the clean sounds very nice but the OD is not there

Sorry to hear that, but that's not a speaker problem.
Even less an internal panel one

All a speaker can do is to receive the already existing OD sound and reproduce it somewhat harsher or smoother according to its own frequency response.

Those Celestions are fine speakers , but have larger diameter voice coils, with longer copper windings ... fine for bass but guitar wise might be somewhat dull.

jm2c , ymmv , etc.

 

[merkaba22]

Sorry to hear that, but that's not a speaker problem.
Even less an internal panel one

All a speaker can do is to receive the already existing OD sound and reproduce it somewhat harsher or smoother according to its own frequency response.

Those Celestions are fine speakers , but have larger diameter voice coils, with longer copper windings ... fine for bass but guitar wise might be somewhat dull.

jm2c , ymmv , etc.

well, yea -- but that amp, my Soldano X88R > Fryette 6L6 based 252 > EVM 12L 1x12 MB cab sounds amazing as it does in every other cab ....

Second, drdecibel [Celestion rep] indicated, since these are known to be fine with OD amps like the Quilter, indicated the baffle ... fwiw, imho, etc.

I am looking for builder's experience

 

[J M Fahey]

Well, I wouldn't compare those 8" Celestions to a 12" EV any day of the week.
The add-on wood reinforcement baffle will help make the existing aluminum one more rigid, you should glue it on so they become one piece, and may help on any vibration you might have, but won't change speaker frequency response at all, even less in the mid-high area where you find them lacking.

FWIW we *do* agree, I said:
"have larger diameter voice coils, with longer copper windings ... fine for bass but guitar wise might be somewhat dull."
and you said:
"the cab, as it is now, is a bit bassey and not focused" which is about the same

I think (may be wrong of course) that you consider maple a brighter wood (which may be true in an instrument) and so might impart some of that to the speakers.
Not so, speakers change sound according to moving mass (the lighter the faster/brighter) and motor strength (larger magnet).

In both areas EV is miles ahead of those speakers.

Does Quilter make good sound with them?
No doubt, amazing sound in fact, but I bet their amps were expressly designed around them, equalizing as much as needed.

Don't think Soldano/Fryette had these Celestions in mind when they designed/modded theirs.

Even the original Pyles were better:
"The Pyles were fine for OD"

But don't take my word for it, go ahead, make and mount that maple baffle and check for yourself.

 

[merkaba22]

yea, yea -- I think gluing a hard wood baffle to the metal will be fine -- tho' it was the Celestion rep who said that if I like EVM 12Ls I will like these and I am sorry, if I was unclear, I have not concluded about the high end and OD --

Odd, too, since Quilter chose them for similar reasons -- speculatively, maybe built around them in part, but nothing of that nature came up in my two discussions with Quilter about using these speakers in this cab with its dimensions, etc....

 

[wrathfuldeity]

I'd suspect the problem with OD is that it is an all metal cab and you might be getting some weird resonant frequencies in the guitar range that might not occur at lower bass frequencies...just a thought.

edit...looks like you got 6 parallel sides in a cube...so the depth, equal sides and closed might be part of the issue. Maybe leave off the side/ends and give it a listen.

 

[merkaba22]

I'd suspect the problem with OD is that it is an all metal cab and you might be getting some weird resonant frequencies in the guitar range that might not occur at lower bass frequencies...just a thought.

edit...looks like you got 6 parallel sides in a cube...so the depth, equal sides and closed might be part of the issue. Maybe leave off the side/ends and give it a listen.

I am tending to see it that way too -- I like the idea of leaving a side panel off to check on responses, will check that out -- for all I know this little cab is better with an oval in the back ...

 

[wrathfuldeity]

idk...if you got a table saw, use and old junk plywood saw blade, mount the blade backwards and cut off about 2-3" off the back of the cab...just run the entire cab against the guide/rail of the table saw. Then glue up a hardwood frame with partial open and use some screws and mount the hardwood frame to fit just inside of the cab...even dado a little edge for the metal to fit in and use some gorilla glue and screws so there no rattle. Wear some good ear protection cause cutting the metal will be screeeaching loud...unprofessional hack here lol.

 

[Geeze]

One thing I would be cautious of - thinking that speakers that sound good with one amp will sound good with another. I built a thiele cab for a friend for his evm12l. Of course I needed to test out the equipment before releasing it - underwhelmed by the sound. To the point I believed the evm12l to be mostly hype to my ears. A few months later I ran a Satellite Barracuda though that cab and WOW -a match made in tone heaven.

Nice looking wood cab by the way.

Russ

 

[merkaba22]

will keep that in mind but with the .050 metal baffle so flexible, I am not sure I hear the best of the speakers to start ....