Building a speaker cabinet with pine plywood.

[Riffster]

I have enough 3/4" pine plywood leftover from a home remodel to build a 1x12 cab.

 

It is the typical Lowe's quality plywood, looks nice but it does have voids in the inner layers for what I can see, outside layers are perfect.

 

My question is, is it worth it to build a cab with this material? has anybody here done this? I know that some reputable brand cabs seem to use regular pine plywood but I wonder if it is treated in any way.

 

My thinking is that it isn't going to sound as good as a Baltic Birch, void-free plywood or as snappy as solid pine but it should be much better than the current most common material, pressed wood.

 

I have all the tools to build it too, and actually have special tolex glue and leftover black cloth-backed vinyl from a convertible top.

[badbluesplayer]

It's going to be fine. Most of the modern cabinet designs are made from pretty acoustically neutral materials.

 

In the old days they made cabs from real boards and they had a certain sound to them. Now most cab makers use plywood anyway, and your plywood might be a little less "live" than birch plywood. But it'll sound fine.

[catnine]

I have enough 3/4" pine plywood leftover from a home remodel to build a 1x12 cab.

 

It is the typical Lowe's quality plywood, looks nice but it does have voids in the inner layers for what I can see, outside layers are perfect.

 

My question is, is it worth it to build a cab with this material? has anybody here done this? I know that some reputable brand cabs seem to use regular pine plywood but I wonder if it is treated in any way.

 

My thinking is that it isn't going to sound as good as a Baltic Birch, void-free plywood or as snappy as solid pine but it should be much better than the current most common material, pressed wood.

 

I have all the tools to build it too, and actually have special tolex glue and leftover black cloth-backed vinyl from a convertible top.

It will be fine I've done it. If any voids are large or excessable you can cut scrap pine to fit and glue them in to fill them.

[Riffster]

I was hoping you two would pitch in since you both have built cabs.

 

The voids are actually only in the inner layers of the plywood, they are small, probably not a big deal.

 

I want to build something along these lines:

 

[Blueblooded]

I have heard, and the logic seems to make sense, is the size (volume) of the cabinet is important and also the front sound board is important to the sound of the cab. Similar to an acoustic guitar, the shape/volume of the body and the way the top of the guitar(front board the speaker is attached to in a cab) are the most important aspects in the tone of both. So, you may want to pick up a better grade of plywood for the front baffle the speaker mounts in as it may make a difference. Can anyone shed more light on this?

[Riffster]

Yea, there are ways to figure out the size of the cab. In the end it is easier to make an open back or a closed back cab. When it gets scientific is with 3/4 closed back cabs and cabs that are ported to the front.

 

The plywood I have is normal quality, the reason for my question is that Baltic Birch is all the rage nowadays, I have a Mesa cab built with marine grade 13-ply baltic birch sprayed with industrial webbing paint on the inside and that thing is tight, I doubt a cabinet can be made better than that.

 

You are right about the front panel, basically you don't want it to be flexible because it will absorb the speaker energy and waste it away, not to mention loss of harmonics. 3/4" plywood is plenty stiff though.

 

I have a Groove Tubes cabinet from the 80's that has 1/2" plywood on the front panel, I just remembered, I may be replacing that soon.

[stein]

I would be more concerned about the type and grade than the "voids" on the inner layers.

 

What I mean, you can get cabinet grade for about 30 bucks a sheet. That's a sanded outer layer. For 30 bucks, it's worth the saving of dealing with standard DC or CDX which don't have a finish grade top layer.

[catnine]

I don't think baltic birch is all that important as a must be plywood. Pine is fine and 3/4" is not going to move. Some of the older fender deluxes like the tweed narrow panel had a 3/8" thick baffle . You are not building that large of cab for one 12" speaker.

 

I have a 1971 Music Master bass amp cab and since I used larger tranny's on the chassis when I rebuilt it into my own splice of two fender amps I had to remove the partical glued in baffle because the tranny's would not clear the baffle and the rest of this same cab is 3/4" pine board. I went to get plywood and I usually buy cutoffs that the anawalt here sells cheap none were of hard wood or baltic birch so I picked out a nice section of 1/2" pine cut the partical board out to leave rails on the sides and screw mounted the new baffle in place into the partical board rails left after cutting and painted it black mounted the grill cloth and used fender stubs and nuts to mount the speaker and it sounds great. Before I mounted the grill cloth I used 1/4" thick birch ply I had left around the baffle to hold the cloth off the baffle like fender did. I used 1/2" plywood because in order to get the clearance i needed to clear the trannys and to consider the 5/8" thick partical board strips I left and I needed just 1/2" more clearance 1/2" ply was as thick as I could go or the speker grill would have been past the edges of the cabs sides. What fender did on champs and many silver faced amps was build the cab and baffle out of partical board set in and glue the baffle and then made a frame of partical board to mount the grill cloth and that was held to the actual baffle by velcro strips.

 

I was always going to later on get 1/2 baltic Birch and remove the partical board (stays) and then fill in the miters in the cabs sides with glued in pine to be the same as the cab and then make new pine stays and mount the new Baltic Birch baffle yet it's been like it is now for 6 years and nothing has warped and the pine baffle is still flat so I just left it alone. The only reason I was going to do that was because the old partical board baffle was sort of brittle, yet not cracked and when I cut the partical board out the sides I left to mount the new baffle to which are about 1" wide felt solid to me.

 

I would much rather have a pine plywood cab and baffle than partical board anyday , partical board is complete CRAP .

 

Just one more point to make. On fender cabs say like the blues JR or blues deluxe just to be more modern replicas of old fender cabs and many of them use 4 to 6 screws to secure the baffle in place so anyone who claims there is sound loss do to the baffle moving think about that, on many of those amps the area the the baffle screws to across the top and bottom is 3/8" thick PARTICAL BOARD. The fender blues deluxe uses 6 screws and hangs a heavy 12" speaker on that. Even some of the old fender bassmans with 4 tens had a 3/8" thick baffle some super reverbs had 1/2" baffels secured the same way only to wood across the top and bottom still 3/8' thick birch and not partical board . I don't know what the new ones are like but I bet they are not all wood or even great wood.