Building pa speaker cabs for a newbie

[NecrosisFactorG]

Hi everyone. I have a fender passport p250 portable pa speaker system which i use as my guitar amp with my Helix LT. No matter how i tweak everything, i always sounds boxy and without prescence. The speaker cabs are made of a very thin plastic and the vibrate a lot. So i decided to build two speaker boxes for the drivers. I've heard that MDF is a good material, but i see a lot of Joint techniques wich i don't have the right tools for. My dad (with basic Wood skills) once made a box with some rectangular pieces of Wood as joints. He driled both MDF sheets on the opposite sides of the corners and screws to secure the sheets. Oh, and he glued all sides before drilling. The results were good, strong joints and very easy to build. But i dont know if this would work on a speaker cab, due to the vibrations. I must mention that the Fender passport cabs have their drivers attached to a screwed front panel (also made with plastic) wich I plan to use as the front panel of the new wood cab, so I don't have to make holes on more MDF sheets. Any advice before buying my material? Thanks a lot!

 

[clydethecat]

In my opinion you don't want to use MDF for a portable cabinet. It's heavy, and breaks if you drop it. Birch plywood would be the preferred material, void-free if you can get it.

 

[NecrosisFactorG]

In my opinion you don't want to use MDF for a portable cabinet. It's heavy, and breaks if you drop it. Birch plywood would be the preferred material, void-free if you can get it.

You're right, I'll look for birch instead. Maybe I'm not worried about weigh now because I only use the PA for rehearsals.

 

[tubegeek]

I can only tell you that those Passport PAs are atrocious and I'd be very suspicious of the drivers as much as the cabinets.

Our church got one as a donation and we overpaid considerably.

And - welcome.

 

[uriah1]

The passport may work in the cloak room of the Howard Johnson. (you are too young to know what that means)

Not sure what your application is, but, dont go overkill either. Some of the best PA I have heard
have been little powered 10's. Of course they are 900watt capable 10s.
Better to have too much power in case of transients. You may not need
mid or horn.

Look at your favorite sounding pa system and see how they are built, etc. Look at
blueprints on the internet thingy.

Wish you luck

 

[Peegoo]

In order for a cabinet to sound good with any speaker, you need to incorporate Thiele-Small (TS) numbers into the build. This tunes the cabinet to the speaker. You start with the speaker and the manufacturer's published TS numbers for the speaker, and go from there. Look online; there are several TS calculators.

Porting is a good option if you want improved lower-range sound.

Recent testing has shown the fluff/foam/Fiberglas filler does little to nothing to improve the sound of a cabinet, so don't waste your time with that.

Here's one look at it:

 

[NecrosisFactorG]

I can only tell you that those Passport PAs are atrocious and I'd be very suspicious of the drivers as much as the cabinets.

Our church got one as a donation and we overpaid considerably.

And - welcome.

Thanks for the welcome! In my experience, they aren't terrible. My gf bought the same system before me (at a bargain). Actually, she paid a lot less than me (both were bought used). She plays a Korg Karma keyboard and everything sounds great! So I decided to try my helix with it and ended up buying one. My only concern is the boxyness. I know these Fenders deliver a great flat response but the plastic cabs reduced a lot of the costs so i want to make my own.

 

[schmee]

As mentioned, MDF is very heavy, and gummy to work with also. It's like thick compressed paper. I would use good ply or if small enough, just use pine. boards. Put some kind of dampener in the cabs. A cab not built like a box is better sounding. ie: wedge or tapered front to back etc.
But I have to say, small used proper PA cabs are a dime a dozen on Craig's List. So much so there aren't as many posted as there used to be because they are very much unsellable.
For what you are doing, you may not need a horn at all and the cheap piezo horn in the Passport may be part of your sound issue.

 

[NecrosisFactorG]

The passport may work in the cloak room of the Howard Johnson. (you are too young to know what that means)

Not sure what your application is, but, dont go overkill either. Some of the best PA I have heard
have been little powered 10's. Of course they are 900watt capable 10s.
Better to have too much power in case of transients. You may not need
mid or horn.

Look at your favorite sounding pa system and see how they are built, etc. Look at
blueprints on the internet thingy.

Wish you luck

Never heard of that, ha! Those 6" drivers in the fender passport truly deliver good tones, I swear of it. They sound better if i stand myself close to the grill and with loud volumes. But my hypothesis is that a wood, strong cab would help a lot to get rid of the boxy sounds

 

[NecrosisFactorG]

In order for a cabinet to sound good with any speaker, you need to incorporate Thiele-Small (TS) numbers into the build. This tunes the cabinet to the speaker. You start with the speaker and the manufacturer's published TS numbers for the speaker, and go from there. Look online; there are several TS calculators.

Porting is a good option if you want improved lower-range sound.

Recent testing has shown the fluff/foam/Fiberglas filler does little to nothing to improve the sound of a cabinet, so don't waste your time with that.

Here's one look at it:

I'll look into it, thanks!

 

[NecrosisFactorG]

As mentioned, MDF is very heavy, and gummy to work with also. It's like thick compressed paper. I would use good ply or if small enough, just use pine. boards. Put some kind of dampener in the cabs. A cab not built like a box is better sounding. ie: wedge or tapered front to back etc.
But I have to say, small used proper PA cabs are a dime a dozen on Craig's List. So much so there aren't as many posted as there used to be because they are very much unsellable.
For what you are doing, you may not need a horn at all and the cheap piezo horn in the Passport may be part of your sound issue.

As mentioned, MDF is very heavy, and gummy to work with also. It's like thick compressed paper. I would use good ply or if small enough, just use pine. boards. Put some kind of dampener in the cabs. A cab not built like a box is better sounding. ie: wedge or tapered front to back etc.
But I have to say, small used proper PA cabs are a dime a dozen on Craig's List. So much so there aren't as many posted as there used to be because they are very much unsellable.
For what you are doing, you may not need a horn at all and the cheap piezo horn in the Passport may be part of your sound issue.

Pine will be another option, as long it's on my budget (I'm a total newbie on this art). I'll check prices on Home Depot for pine and as mentioned before, for birch plywood. I should also mention that my specific passport model doesn't have any horns on it, they're only 4 4" speaker FRFR drivers with two small vents. I stuffed both cabs with a cotton blanket (used a thick one) with very minimal difference. So if the wood cab doesn't make this thing better I'll blame the speakers. Maybe I'll expend a lot with it, when I could buy another PA system, but the building process is exciting to me, so I can learn a thing or two. And i can always return to attach my speaker front panel back to the original plastic cab

 

[jvin248]

.

Go with pine, narrower boards and glue them up as they will generally save you money that way. Birch plywood will be prohibitively expensive plus you'll need to buy a whole sheet.

Better tones are a result of better sizing with this thing called math...
https://www.diyaudioandvideo.com/Calculator/SpeakerBoxEnclosure/

Generally, closed back cabinets (correctly sized) will be smaller, lighter, and cheaper to build than ported (correctly sized) cabinets.



.

 

[W.L.Weller]

https://www.parts-express.com/

These guys sell the odds and ends you'll need to make solid cabinets. MDF is a good choice if you don't have to move them, it's much less resonant than pine (or the plastic you're dealing with).

A problem you may have trying to re-use the baffle (what the speakers are mounted to) from your cabinets is fastening the baffle to your homemade cabinet in a solid way that won't buzz or rattle. But making your own baffle isn't too hard if you have a jigsaw or a router.

 

[mfguitar]

You may be in for sticker shock at the lumber yard, prices have gone through the roof. It may make more sense to find some speakers, most are moving to powered so you can find some great deals on passive speakers that will have better components than what you have. If you were close I'd give you a pair

 

[24 track]

too bad you were not closer , I have a ton of PA speakers , 18", 15" 12" 10" horns , here is a set of 4560 bins with peavey horns i built, I took apart a set AA7 cabs to make these . I loaded the cabs with altec mid range 15's perfect for small pa gigs and also for side fill monitors and they are not heavey

 

[Ringo]

Used older PA gear is abundant and to be had cheap usually, especially if you aren't concerned about it being big and heavy, no one really wants the old big gear these days.
It still sounds good but modern more efficient smaller lighter speakers are what most folks want and use.

 

[NecrosisFactorG]

Thanks for all your answers, guys! Actually, I think you're seriously right about the fact that everyone has turned over lighter modern stuff. it's kind of funny, but I remember people keeping large wood speaker boxes in their houses, with or without any speakers, but completely abbandoned. I truly appreciate all of your kind advices and wishes, and i think many people are willing to sacrifice some sound quality for health and comfort reasons. And above all, maybe the average listener won't hear a difference between plastic and wood enclosures. Anyways, (sorry for the long and thoughts ) Just for the sake of not giving up on enhancing guitar tone, is there any method to drastically reduce Vibrations on plastic and make them less resonant? Any material experiences? Thanks!

 

[tubegeek]

too bad you were not closer , I have a ton of PA speakers , 18", 15" 12" 10" horns , here is a set of 4560 bins with peavey horns i built, I took apart a set AA7 cabs to make these . I loaded the cabs with altec mid range 15's perfect for small pa gigs and also for side fill monitors and they are not heavey

View attachment 774056

I'll be right over.

Coming from Brooklyn, give me 2 days.

 

[Ringo]

Thanks for all your answers, guys! Actually, I think you're seriously right about the fact that everyone has turned over lighter modern stuff. it's kind of funny, but I remember people keeping large wood speaker boxes in their houses, with or without any speakers, but completely abbandoned. I truly appreciate all of your kind advices and wishes, and i think many people are willing to sacrifice some sound quality for health and comfort reasons. And above all, maybe the average listener won't hear a difference between plastic and wood enclosures. Anyways, (sorry for the long and thoughts ) Just for the sake of not giving up on enhancing guitar tone, is there any method to drastically reduce Vibrations on plastic and make them less resonant? Any material experiences? Thanks!

Maybe some of the sound absorbing mat material that they use for car stereo speaker boxes, Dynamat is a brand name and is pricey but there are generic versions available.
It's self stick I think

 

[NecrosisFactorG]

too bad you were not closer , I have a ton of PA speakers , 18", 15" 12" 10" horns , here is a set of 4560 bins with peavey horns i built, I took apart a set AA7 cabs to make these . I loaded the cabs with altec mid range 15's perfect for small pa gigs and also for side fill monitors and they are not heavey

View attachment 774056

Thanks a

You may be in for sticker shock at the lumber yard, prices have gone through the roof. It may make more sense to find some speakers, most are moving to powered so you can find some great deals on passive speakers that will have better components than what you have. If you were close I'd give you a pair

Thanks a lot, guys. Yep, I'm too far (I live in Mexico City) but if were near you I would buy share a drink with you. Thanks again!