Speaker Boxes

[Warrior]

I know there are some guys and gals here that are knowledgable in the production of speaker boxes. I have been donated some speakers and the boxes are like melamine and not in the greatest shape. I would like to build new boxes for them.

Do I need to use a manmade product like PB, ply, or MDF? Solid wood, OK?

Any tips would be appreciated.

Eiji Fuller

 

[mastercabman]

i would not use light weight wood.vibration may occur and it will distort the overall sound.i would stay with something heavy like pb or mdf.
make sure you glue all joints.i use to build large speaker boxes for stage sound.

 

[Mirko]

3/4 MDF is the best Eiji, you may also want to check with the manufactures air space and port diameter specs for your speakers.

Mirko

 

[JayStPeter]

The best speaker materials are baltic birch ply and MDF.  Any ply with voids and solid wood are not as good.  MDF is the most common for speaker builders since the usual reason to build your own speakers is to save some money while getting a better product.  BB ply is 3x the cost for minimal sound benefit.  But, it is easier to work with and nicer looking if you're going for a natural finish later.  MDF requires extra finishing effort.

 

[robtonya]

I built some for a friend. The spec sheet said not to use MDF as it was not near strong enough, and recomended something like 1" 1/2 thick marine grade plywood. It did state if you had to, you could use down to 3/4" marine grade (no voids in the wood). I ended up using 13 ply 3/4" baltic birch, and have heard no complaints. The speakers was 18" Peavey lowriders. 3500 watts, and he had the amps to push it, so I was nervous that he would blow my boxes apart. Here is a picture of them. If you need any help, let me know. I am no professional though.

 

[robtonya]

Also here is a link to where I ended up buying most of the cabinet hardware, and carpet.       http://www.partsexpress.com/connectors.cfm

 

[mastercabman]

I built some for a friend. The spec sheet said not to use MDF as it was not near strong enough, and recomended something like 1" 1/2 thick marine grade plywood. It did state if you had to, you could use down to 3/4" marine grade (no voids in the wood). I ended up using 13 ply 3/4" baltic birch, and have heard no complaints. The speakers was 18" Peavey lowriders. 3500 watts, and he had the amps to push it, so I was nervous that he would blow my boxes apart. Here is a picture of them. If you need any help, let me know. I am no professional though.

Not to use mdf,but to use marine grade plywood?  maybe for exterior use,but i never heard anything for interior use for speakers.
mdf is strong,and stable,and pretty good for sound(imo).
i remember using particle board and we cover it with that dark grey carpet like. again make sure it is build solid,and glue all joints.
as for speakers,we usedeavey,electro-voice,jbl,fostex,cv,and i think we use radio shack one time!!  and more but i can't recall right now.

 

[bruegf]

I know there are some guys and gals here that are knowledgable in the production of speaker boxes. I have been donated some speakers and the boxes are like melamine and not in the greatest shape. I would like to build new boxes for them.

Do I need to use a manmade product like PB, ply, or MDF? Solid wood, OK?

Any tips would be appreciated.

Eiji Fuller

Eiji,

In a previous life, I designed speaker cabinets and electronics sheet metal enclosures for Electro-Voice, a US based mfr of professional audio gear.  We used, melamine covered medum density particle board, baltic birch plywood, a thick felt covered oriented strand board, and rotomolded HDPE  for our cabinets, depending on the market and intended usage.  All of the materials worked well.  The main thing is to not make the panels so thin that it can start resonating at some frequencies.

Fred

 

[robtonya]

I built some for a friend. The spec sheet said not to use MDF as it was not near strong enough, and recomended something like 1" 1/2 thick marine grade plywood. It did state if you had to, you could use down to 3/4" marine grade (no voids in the wood). I ended up using 13 ply 3/4" baltic birch, and have heard no complaints. The speakers was 18" Peavey lowriders. 3500 watts, and he had the amps to push it, so I was nervous that he would blow my boxes apart. Here is a picture of them. If you need any help, let me know. I am no professional though.

Not to use mdf,but to use marine grade plywood?   maybe for exterior use,but i never heard anything for interior use for speakers.
mdf is strong,and stable,and pretty good for sound(imo).
i remember using particle board and we cover it with that dark grey carpet like. again make sure it is build solid,and glue all joints.
as for speakers,we usedeavey,electro-voice,jbl,fostex,cv,and i think we use radio shack one time!!   and more but i can't recall right now.

I know, but that is what the Peavey spec sheet said. I don't know much more than that. The friend of mine said the intention of these speakers would be used in a stadium, but he has them in his apartment. He has a whole wall of speakers stacked on top of them. Marshal stacks I think he calls them. I am glad I don't live too close to him though.

 

[JayStPeter]

I built some for a friend. The spec sheet said not to use MDF as it was not near strong enough, and recomended something like 1" 1/2 thick marine grade plywood. It did state if you had to, you could use down to 3/4" marine grade (no voids in the wood). I ended up using 13 ply 3/4" baltic birch, and have heard no complaints. The speakers was 18" Peavey lowriders. 3500 watts, and he had the amps to push it, so I was nervous that he would blow my boxes apart. Here is a picture of them. If you need any help, let me know. I am no professional though.

Not to use mdf,but to use marine grade plywood?  maybe for exterior use,but i never heard anything for interior use for speakers.
mdf is strong,and stable,and pretty good for sound(imo).
i remember using particle board and we cover it with that dark grey carpet like. again make sure it is build solid,and glue all joints.
as for speakers,we usedeavey,electro-voice,jbl,fostex,cv,and i think we use radio shack one time!!  and more but i can't recall right now.

Yeah, robtonya is right.  Marine grade and baltic birch are basically no-void plywood.  They wind up a little stiffer than MDF when a big driver is trying to blow the box apart.  With no voids and the many-thin-layer construction, they are also very resistant to vibration.  You'll find a lot of the DIY speaker guys will still use MDF for their big drivers, but they will put a bunch of internal bracing in there.  It's still a great bang for the buck, but not cost effective to mfr with all the bracing.  Standard plywood, with voids and fewer layers is not a good material at all due to it having a resonant freq that's right in the middle of most speakers range.
Many mfrs. use less expensive materials like particle board, but that's mostly for cost savings at the expense of ultimate performance.  But, when you design your drivers so you can have single component crossovers, there's going to be some performance sacrificed anyway.  Ultimately, that's the difference between cheap (

 

[mastercabman]

i like to add that i use to build boxes back 20 + years ago,and most of it was for stage speakers.the heavier they were,the better.there is a difference between a system putting out 1000 watts and a system that can put out 20,000 watts!      or 80,000 watts +!!!
when you stack speaker cabs on each other they can easily "walk away" if they are not secured.

 

[mastercabman]

I built some for a friend. The spec sheet said not to use MDF as it was not near strong enough, and recomended something like 1" 1/2 thick marine grade plywood. It did state if you had to, you could use down to 3/4" marine grade (no voids in the wood). I ended up using 13 ply 3/4" baltic birch, and have heard no complaints. The speakers was 18" Peavey lowriders. 3500 watts, and he had the amps to push it, so I was nervous that he would blow my boxes apart. Here is a picture of them. If you need any help, let me know. I am no professional though.

Not to use mdf,but to use marine grade plywood?   maybe for exterior use,but i never heard anything for interior use for speakers.
mdf is strong,and stable,and pretty good for sound(imo).
i remember using particle board and we cover it with that dark grey carpet like. again make sure it is build solid,and glue all joints.
as for speakers,we usedeavey,electro-voice,jbl,fostex,cv,and i think we use radio shack one time!!   and more but i can't recall right now.

I know, but that is what the Peavey spec sheet said. I don't know much more than that. The friend of mine said the intention of these speakers would be used in a stadium, but he has them in his apartment. He has a whole wall of speakers stacked on top of them. Marshal stacks I think he calls them. I am glad I don't live too close to him though.

marshal is a brand of electric guitar amp and speaker. they were very popular back in the 80's among hard rock/heavy metal band!
they are know for their "tubes amp" 
rock bands like metalica used them and may still use them now.
i used peavey,fender,gallian grugger(i think that's how you spell it),

 

[robtonya]

Yeah, he's a metalhead. If I see him, I will have to get a picture of his set. I can see a speaker with 80,000 watts walking away easily. I learned a little when I was building his. I knew he had 10,000 watts, so I was nervous about him blowing them apart.

p.s. Hey Nick. Good to see your posts again, and I liked your links. Someday maybe yours or mine speaker boxes will be in there.

 

[mhch]

also: http://www.speakerbuilding.com/

 

[b_yxo]

Eiji,

I these are cheap speakers, you are not going to improve it much by building state of the art braced enclosure.

I would build outer box out of plywood or MDF (painted or veneered) and glue it around existing speaker cabinet. This way you will get a speaker that internally has the same volume and stuffing as designed originally plus much stronger and acoustically dead enclosure that you can finish to your liking.
Just a few points:

- Copy all original box openings to the outer box, then glue outer box to existing speaker enclosure, finish and reinstall drivers and a port(if speaker is ported). The length of the port should be the same as original. If there is internal support for the driver, extend it for the width of the newly added front.
- Drivers should be installed flush with front panel and airtight. Do not use silicon to seal drivers, rather use gasket between driver and enclosure.
- I would add 1/2 in. MDF or ply for the sides and 3/4 in. or 1 in. for the front.
- Round over 2 font corners so the width of the front panel is equal to one of the original speaker.
- Add cones or spikes to decouple the speaker from the floor.

You can get cones, grill cloth e.t.c from one of companies that sell kits and accessories for speakerbuilding:
http://www.madisound.com/http://www.zalytron.com/http://e-speakers.com/
in addition to already mentionedhttp://www.partsexpress.com/

Good luck.

 

[Steveo48]

i would not use light weight wood.vibration may occur and it will distort the overall sound.i would stay with something heavy like pb or mdf.

My kids at school like to build speaker boxes for their cars.  They drop humongus (to me anyway) 15" and 18" woofers into their trunks, beds and back seats for "a better base".  8) We've all heard it rolling down the street.  :

Anyway, I asked a local car builder about speaker box construction.  He told me (I don't know where he got his information) to use MDF because it vibrates less than ply since it has absolutely no grain.  Cost wasn't a factor for him, vibration was.

Steve

 

[ken257]

The reason for using plywood in pro audio is that the speakers take a lot of abuse being thrown around and banged into things. This is why mdf is not strong enough, however for home speakers the situation is much different. MDF will produce a better sounding speaker then ply because of its density which means less panel resonance. It is ok to build a box out of a visually appealing material and then line it with mdf.

If you have parameters for the drivers I can run them through speaker box/crossover design software for you.

 

[robtonya]

The reason for using plywood in pro audio is that the speakers take a lot of abuse being thrown around and banged into things. This is why mdf is not strong enough, however for home speakers the situation is much different. MDF will produce a better sounding speaker then ply because of its density which means less panel resonance. It is ok to build a box out of a visually appealing material and then line it with mdf.

If you have parameters for the drivers I can run them through speaker box/crossover design software for you.

I wish I had your help designing mine.

 

[Bill Wyko]

Most speakers are very sensitive to the volume of the enclosure. Also the port is a science too. When you make the port you should round over the inside and outside edges of the port. In addition, a port should always have at least a distance from the back wall equal to the diameter of the port. We built a Blazer in 2002 that set the record for the loudest system ever with less than 720 sq in of speaker cone area. It's highest decibel reading was 176.5 DB. I built the box with 2 layers of 3/4" Baltic Birch and 1-1/2 Plexiglass. Even with 48,000 watts the box didn't move at all. I prefer the Birch also because it doesn't soften up with age. I've found that with vibration, MDF will loosen screws or nails over long periods of time. If you want to change the dimentions make sure you don't change the volume or port size. PM me if you need any help, I have access to a program for designing boxes.

 

[Woodenfish]

We built a Blazer in 2002 that set the record for the loudest system ever with less than 720 sq in of speaker cone area. It's highest decibel reading was 176.5 DB. I built the box with 2 layers of 3/4" Baltic Birch and 1-1/2 Plexiglass. Even with 48,000 watts the box didn't move at all.

Maybe I'm just getting old, but what's the point in all of this?