Beyma SM-112/N Enclosure Help

[Vostro]

Hi I really hope someone will have time to help.
I have a Beyma SM-112/N Driver and want to use it as a Music subwoofer at home.
I'm not really sure if its a good driver for this use, any advice will be nice.

What I really need is a design or a Sub enclosure for this speaker,
I've tried once in the past to make a box on my own for another speaker and I wasn't happy with the results,
That's why I ask for help for this one.
My main use will be listening to music, all types, from Linkin park to Enigma, to any pop music.

My left and right speakers are BOSTON ACOUSTICS A26 Bookshelf Speakers, on DIY APEX amplifiers.

Thanks
http://profesional.beyma.com/pdf/SM-112%20NE.pdf

 

[bjorno]

Hi I really hope someone will have time to help.
I have a Beyma SM-112/N Driver and want to use it as a Music subwoofer at home.
I'm not really sure if its a good driver for this use, any advice will be nice.

What I really need is a design or a Sub enclosure for this speaker,
I've tried once in the past to make a box on my own for another speaker and I wasn't happy with the results,
That's why I ask for help for this one.
My main use will be listening to music, all types, from Linkin park to Enigma, to any pop music.

My left and right speakers are BOSTON ACOUSTICS A26 Bookshelf Speakers, on DIY APEX amplifiers.

Thanks
http://profesional.beyma.com/pdf/SM-112%20NE.pdf

Hi Vostro,

The Beyma driver is IMO very suited for a quality quarter-wave based sub:

Here is an example constituting a folded OD_T-TQWT (Offset Driver_Tapped-
Tapered Quarter-Wave Tube that should be lined with damping material.

b

 

[Vostro]

Thanks for the reply, but would this be compact, I don't have a big living room,

 

[tinitus]

..... but would this be compact......

very high Fs, and high Qts
but would still be tempting to try it with big slot ports a'la Onken style ......Bjorn, are you there ?

 

[tinitus]

I did try a calculation on vented BR and came out with 130 liter netto, with very low roll off around 30hz
and interestingly it appears to handle big slot ports

 

[bjorno]

I did try a calculation on vented BR and came out with 130 liter netto, with very low roll off around 30hz
and interestingly it appears to handle big slot ports

Hi tinitus,

You're absolutely right, 130L is optimal for the driver. From this volume its easy to scale a port system to suite a conventional BR or quarter-wave type.
Note: Use an seeding port area of ~Sd/3 to start with.

Use HR or an another program that take in account the port placement and can handle quarter-wave resonances.

First: Keep the box volume constant(Opt BR) and resize the port length (to fit an enclosure of your choice), then add port area until the BW drops more than you wish.

Here is a simulation that can be used as starting point to expand the port sizes. Picture#1:

b

Ps:
In another thread we talked about adding cone weight to a PD.1550 and
Ive lost track of the original thread but posting my suggestions here instead. Picture#2:

this one ? I can move it to there ? http://www.diyaudio.com/forums/subwoofers/217038-precision-devices-pd-1550-a.html

Of course ,move it where it belongs

b

 

[Vostro]

Thanks guys but I think I'm in over my head, I have never designed a enclosure, and I have no idea

 

[tinitus]

what do mean ? its just a box
you have the woofer, right ?

we should be able to make you a drawing, if thats all you need to build it

but ofcourse you also need a plateamp with xo
do you know anything about these things ?

 

[Vostro]

hehe I looked at the numbers and got lost, yes I already have the speaker,
If the forum members are willing to help with a darwing, Ill be so so happy,

Im going to use a Apex B500 amplifier with his subfilter preamp.

Thanks again for being so helpfull.

I have some knowledge on amplifiers, just not speakers
Ive been busy on amp design as a hobby.
http://www.diyaudio.com/forums/solid-state/213757-second-attempt-building-my-own-amp-scratch-7.html

 

[tinitus]

hehe I looked at the numbers and got lost....

yeah, I know ......bjorn is 'advanced'

but we still got the same number for vented, 130liter(netto)
brutto its close to a box like 55x55x55cm
not exactly those numbers
just to get a figure of its size
is that a size you can handle ?

also need to know what kind of wood you can get

 

[Vostro]

Thanks 55x55x55cm is compact

Not tiny but Ill make place to fit it

MDF is cheap here, but if ply is better I can shop around.

 

[tinitus]

for a sub, I think MDF would be ok to use

how thick MDF ?

finish ?

tools?

 

[Vostro]

16mm MDF like picture,

Sadly I live in an appartment and dont have the greatest of tool selections,
I have Hand tools, like drill and jigsaw,
My wood supplier cuts wood, so I usually get most of the cuts done, then alter at home as needed,
If I need more help I can always contact a friend.

 

[tinitus]

16mm ? it will need some 'tricks'

I suppose you dont have clamping tools, and thus need to use screws ?
you are familiar how to use screws with MDF ?

what kind of screws ?

what kind of glue ?

btw, your wood supplier, he does cut it 100% accurately and smooth, right ?

 

[Vostro]

well to be honest, Im not sure, i would guess piloting holes and using wood screws with woodglue,

But advice is needed,

No there curts are sometimes not square enough, but I'll chat to them and ask them nicely to be exact. they use big table like saws and are as smooth as in the pic above, but thats just a offcut from previous project.

Warm Regards

 

[tinitus]

I will work on a design according to your skills, tools and materials
I may have something we can look at tomorrow

basic design idea
corners are ports
but may still change

 

[tinitus]

ports moved a bit
dont worry about the punched lines
they are for my own pleasure only

 

[tinitus]

assembling point of view, starting with inner structure

 

[tinitus]

and more detailed

 

[tinitus]

corrected for calculated port size
4 ports of each 200x48mm
but so far just an estimate