Simple cab design 1x12... your comments please

[dhsierra1]

One tradeoff for using a bigger box for more bass extension is you reach xmax sooner. It's your judgement call to make. Try modeling them in an even 2 cu.ft. per and see what you think. I'm leaning that way for re-doing mine, seems to be a decent middle ground, for my preferences anyway, your needs/wants may be entirely different. For how mine sound, I don't really need the extra 1/4 of a cubic foot for anything.

Sounds like mine (two 1-12s) came in very close to yours, Will. They were 2.1 cu ft w/Fb of 42 Hz using one 4" port. No overextension or chuffing issues playing a few different 4 string Fenders going up to 500 watts. No mid driver, though, but the mids and highs were what the guy wanted. I know, I know, dispersion..... I'd do these again, though.

OP, what amp are you planning on using w/your cabs?

 

[rpsands]

Exceeding xmax at 175 watts instead of 225 watts is something like a sacrifice of 1db of overall volume. If you gain more than 1db of low end sensitivity it's well worth it. Especially for deltalites, which really like a big box to smooth out the bottom end.

 

[Petebass]

I'm not sure about bassbox pro, but a lot of speaker simulation program's create their excursion graphs on the assumption of pure sine waves. Bass guitar notes are far from pure sine waves, and most electric basses have a weaker fundamental than first harmonic anyway. So in the real world, speakers often perform much better than those excursion graphs would indicate, within reason of course.

 

[LowGrowl]

Exceeding xmax at 175 watts instead of 225 watts is something like a sacrifice of 1db of overall volume. If you gain more than 1db of low end sensitivity it's well worth it. Especially for deltalites, which really like a big box to smooth out the bottom end.

I'm not sure about bassbox pro, but a lot of speaker simulation program's create their excursion graphs on the assumption of pure sine waves. Bass guitar notes are far from pure sine waves, and most electric basses have a weaker fundamental than first harmonic anyway. So in the real world, speakers often perform much better than those excursion graphs would indicate, within reason of course.

KILLER FACTS! thankyou very much.

I'll get this done by the weekend

 

[billfitzmaurice]

Exceeding xmax at 175 watts instead of 225 watts is something like a sacrifice of 1db of overall volume.

More like 1/2 dB. Inaudible.
As for group delay that's also inaudible, so don't even bother looking at the chart for it.

One tradeoff for using a bigger box for more bass extension is you reach xmax sooner.

Far more often than not it's not a trade off. In most cases the added sensitivity and extension more than makes up for the lower displacement limited power. To see what's really happening the graph with the most relevance is that for maximum SPL, as it simultaneously takes into consideration Pe, xmax, sensitivity and frequency response.

 

[will33]

True^^ Especially when coming from the angle of getting all the performance you can from your chosen driver, but, it depends on what the OP's goals are. For an electric bass specific speaker, sometimes you just don't need all that deep extension to sound good. "Rather have it and not need it" still applies and you can always fix stuff with eq, bit, if you're looking to keep a fairly simple, plug-n-play, good sounding bass rig, most bass amps don't have all that precision eq, adjustable filters, etc. In that case, you might be further ahead to make the speaker come close to your desired sound so there's less stuff to adjust/fix, even if that means giving up a little bit of extension it might otherwise be capable of. If there was only one right way, we'd all play the same thing and that would be pretty boring.

Not trying to argue the point here, just looking at it from a little different perspective.

 

[LowGrowl]

Thank You all for your insights, This is getting more and more exciting

So Finally! I just began the building yesterday. I'm starting with the simple 1x12 design.

I've been checking alot of designs regarding speaker placement in the baffle. fearFull's mainly.
I would like to say that I understand everything about dispersion BUT I DON'T.

So i came up with this design just from looking at the pictures of various completed projects:

22" inches wide to match with a standard rack

And vertically Stacked:

What do you guys think about it?
Ray

 

[will33]

Assuming that's to scale, you have some wiggle room in the baffles, I'd try to shuffle the drivers around to get them all as close to a straight line as you can. If they just plain won't fit all vertically, move the woofer-only cabs driver to the middle of the baffle, assuming a common 800-1khz crossover point. IMO.

 

[will33]

In other words, look at a fEARful 12/12/6 or 12/6-12sub. Don't just copy the whole design, it's designed for different drivers than what you're using, but get as close to that alignment as you can while still keeping some other aspect of your design you don't want to totally give up....portability or whatever. It looks as if you could go totally vertical in your bottom pic, although that would throw the alignment off if you ever did stack them sideways.

 

[BogeyBass]

single shelf port...yuck offset non vertical 6.5"... yuck

Try instead doing Symmetrical 4x3" round ports mounted close to driver, and a vertical 6.5

showing a extra 1/2" strip added to make a 1" false front. makes the cabinet look beefy.
Then another 1/2" strip for a frame. For attaching cloth or mounting metal grill

 

[BogeyBass]

meh maybe...still dont like putting 6.5 in with same cabinet.
would like to do a dedicated woofer section. then add a 6.5 top box.....but this could do.

 

[LowGrowl]

Hi there....
I have revisited the terrible original design into this:

better?

Ray

 

[will33]

Ya, but do 4 ports surrounding the woofer per Bogey's design, rather than the 2 there. They don't have to be quite as big when doubling them up, ie: four 3", instead of two 4". You'll end up with more port area in the end, and alleviate cone-rocking at high output. I'm close to settling on my next re-build being just that, but a W/M/W alignment all in one box with 6 ports. In separates, those little changes will make it the best you can get, with the option of setting the top cab upside-down, depending on how much mid you want in your ear.

PS. I thi.k it's great you're putting all this forthought into this and letting us tweak your design. Now for the crossover...the toughest...and most important part.

 

[BogeyBass]

Yah my only other thoughts are instead of doing a cabinet with a 12" with a 6.5".
and then just a 12" cabinet

I like the idea of not trying to squeeze the 6" in with the 12. And Dedicate the Enclosure to just the 12". Then you have a matching pair of speakers. Otherwise I just dont like how close the speaker
is mounted to the lower wall. And how the extra space is going to change the volume of the cab compared to the single 12.

I think its possible to add the 6.5" and whole crossover into a separate top box. Then you have a system where if needed
you can add the HF. Or you can just run a matching pair of 12's
with equal volume and symmetrical ports.

Another thing which could be brought up is since the 12" could be crossed over higher. I think its possible to use a lower cost
sealed 6.5" speaker. Yes I know your all going to scream bloody murder when it comes to sealed midranges. But I think the trick
to them is to cross over higher around 800hz. Then you could not even worry about a box for the 6.5 and do some sort of cool
looking open baffle thing. Since sealed speakers dont need a full
box. Plus now your 6.5" can have more setback since its not mounted to the same baffle. And i'm sure you could measure it,
but a generic 2 or 3" of setback might even offer some delay compensation.

Anyhoo, here is a quick design for a single 12" with 4 round ports.
offers better distance from the cabinet walls for the woofer.
The 6 and 12 are just to squeezed together, (that is just my opinion)

just an idea for making the thin 1/2 ply to have a beefy appearance by adding a false front with a 1/2 x 1" poplar strip.
Then making a frame for a cloth grill or a standoff for a metal grill. With another 1/2 x 1/2 poplar strip. Should work
unless you guys see a reason it wont work, this was just a quick idea.

 

[BogeyBass]

Also the 1/2 ply is saving weight.
But I was also thinking that bracing is important, and 4 round ports
could make bracing a challenge.

But! just thinking that alot of weight could also be saved with well done minimal bracing.
Bill has mentioned that you could just use Wood Dowels to
tie the front and back together. Same with the sides, Top and Bottom.
So hopefully if Bill is still floating around, I'd appreciated your input
on this design of using Wood Dowels.
I think the only hard part about mounting 4 round ports is bracing.
and the Dowel method that Bill has mentioned should solve it really easy.

this is just for fun, trying to see if my grill mount idea will work.
And see some options for covering cloth or Metal.
I think metal grills are ugly (sorry) ......But some
strips of metal might clean it up and look nice. It will hide the standoffs and makes a good place to add your own label or something........

 

[Arthur Strand]

Forget MDF. It is horrendous to work, it stinks when sawing it, it is weighty and would be the wrong stuff for a baffle board. Pine ply should be adequate. for the enclosure - sides back top & bottom. Just measure twice cut once or get it done at the merchant's. You could think carefully about how you intend to screw and glue the sides, bottom and top together with a frame. Or whatever method you choose - the main thing to focus on is the baffle board. Measure twice, get the circle centre correct and use compasses to draw the circle, allowing an inside circumference and a wider circumference where the speaker joins the board. Accuracy counts. If you paint the board black with Blackboard paint, make sure it has dried before you drill your pilot holes and remember to tighten the T nuts so that the teeth go right into the board. Covering the exterior of the box with vinyl is an art to be considered carefully before tackling the job. When assembled you could add corner protectors and grill to your liking. Get the impedance correct if adding a smaller speaker like an 8" or 6.5" which I do not recommend and would prefer the solitary 12" for bass. Ensure that the bass amplifier is compatible with the speaker(s) and good luck. View my website Home page to see Tonehenge - my 1970s stereo bass rig to drive my Rickenbacker Stereo Bass!!!
Escutcheon Media - Home
2 x 2 x 15" 421 8H Altec bass Speakers in self-built cabinets (chipboard - and Baffle of Ply) + commissioned custom built stereo bass amplifier 200watts per side. It is approaching 40 years old and still works as well as it did then!!!

 

[billfitzmaurice]

Bill has mentioned that you could just use Wood Dowels to
tie the front and back together. Same with the sides, Top and Bottom.
So hopefully if Bill is still floating around, I'd appreciated your input
on this design of using Wood Dowels.
I think the only hard part about mounting 4 round ports is bracing.
and the Dowel method that Bill has mentioned should solve it really easy.

The bracing looks fine, the cleats at the cabinet corner joints are wasted lumber and unnecessary weight. I'd use triangular corner ports, they double as bracing for the baffle and sides/top/bottom and are easier to implement.

 

[BogeyBass]

Ok one more then I'll stop spamming your thread with pictures.
Just a quick something to show my 6.5" open baffle.
using a sealed 6.5"
Many shapes and ideas could be used, but something similar
for a open look and include the jack and crossover.

(edit) opps forgot
so maybe a LA6-CBMR

 

[LowGrowl]

Ya, but do 4 ports surrounding the woofer per Bogey's design, rather than the 2 there. They don't have to be quite as big when doubling them up, ie: four 3", instead of two 4". You'll end up with more port area in the end, and alleviate cone-rocking at high output. I'm close to settling on my next re-build being just that, but a W/M/W alignment all in one box with 6 ports. In separates, those little changes will make it the best you can get, with the option of setting the top cab upside-down, depending on how much mid you want in your ear.

PS. I thi.k it's great you're putting all this forthought into this and letting us tweak your design. Now for the crossover...the toughest...and most important part.

Thank you will33 Im in the learning zone here

I played a little with the bassboxpro and found that 4 x 3" ports would ask for a 12.25" long ports and the internal space with the recessed baffle is only 14.25" so there are just 2" between the back pannel and the end of the tubes.
Not enough to avoid turbulance?

Yah my only other thoughts are instead of doing a cabinet with a 12" with a 6.5".
and then just a 12" cabinet

I like the idea of not trying to squeeze the 6" in with the 12. And Dedicate the Enclosure to just the 12". Then you have a matching pair of speakers. Otherwise I just dont like how close the speaker
is mounted to the lower wall. And how the extra space is going to change the volume of the cab compared to the single 12.

I think its possible to add the 6.5" and whole crossover into a separate top box. Then you have a system where if needed
you can add the HF. Or you can just run a matching pair of 12's
with equal volume and symmetrical ports.

Another thing which could be brought up is since the 12" could be crossed over higher. I think its possible to use a lower cost
sealed 6.5" speaker. Yes I know your all going to scream bloody murder when it comes to sealed midranges. But I think the trick
to them is to cross over higher around 800hz. Then you could not even worry about a box for the 6.5 and do some sort of cool
looking open baffle thing. Since sealed speakers dont need a full
box. Plus now your 6.5" can have more setback since its not mounted to the same baffle. And i'm sure you could measure it,
but a generic 2 or 3" of setback might even offer some delay compensation.

Anyhoo, here is a quick design for a single 12" with 4 round ports.
offers better distance from the cabinet walls for the woofer.
The 6 and 12 are just to squeezed together, (that is just my opinion)

Hey BogeyBass! I like the idea of two matching boxes for the 12"s. Maybe the upper box could be 2 boxes in one. One for the 12 (exactly tha same as the lower box) and one for the 6.5 wether it's closed or open driver with a little box. Crossover could fit there too.

The bracing looks fine, the cleats at the cabinet corner joints are wasted lumber and unnecessary weight. I'd use triangular corner ports, they double as bracing for the baffle and sides/top/bottom and are easier to implement.

Interesting! the triangular corner ports would save bracing... My only concern is that the would be a little far from the driver:

Thank you all for your kind advice
Ray

 

[will33]

I just factored in the space occupied by the sub-chamber in my top box and built it a coupke inches taller than the bottom one so my woofers are sitting in equal volume. You can do your mid like that, or in a separate box, it ends up the same either way.