would this DIY sub be ok ??

paulst10 · 09-01-2007, 11:46 AM

hi all, would appreciate some opinions on this sub that i intend to build

i plan to upgrade my 12.2 driver to a 12.3 (£100)

get my mate to build me a box with the same or similar dimensions as an svs sb12 (14"h x 14"w x 15"d)

buy an entire back plate from BK (gonna go for the 300w version used in the monolith @ £184), as i dont have any experience in building my own, i am thinking the back plate would be the far easier option as everything is already fitted and all i need to do is connect 2 cables to the driver .. apparantly

this one .. http://www.bkelec.com/Modules/bsbpv300.htm

whereas the amp module (£92) needs soldering and some experience in sub making ... i gather

best regards

paul

Nimby · 09-01-2007, 12:01 PM

Bung an email off to SVS technical support to see if the 12.2 is suitable for a small sealed box.

SVS are usually very helpful and may suggest an alternative design based on their expert knowledge of their own drivers.

stevefish69 · 10-01-2007, 7:06 AM

I am in the middle of getting the bits together for a bit of DIY myself.

Essextubes have just quoted me £55 delivered for a tube the same dimentions as my 20-39 so i may go down this route.

You'll find my thread on in the spot with some links to suppliers for Amp modules and Ports. Hope this helps.

http://www.hometheaterspot.com/htsth...e/0#Post818999

http://www.essextubes.com/

asdonk · 10-01-2007, 9:35 AM

the BK amp will do the trick, the same subamp is used in the BK electronics Monolith

paulst10 · 10-01-2007, 9:39 AM

thanks for the info lads

steve ... any chance you could let me know the dimensions of the tube you are getting, as its got me thinking now ... cylinder or box .. hmmmn

i got an email back from tom @ SVS ..

Quote:

Hi Paul,

Sure, that will work fine for the 12.2…just don’t expect a “SPL monster” or anything like that..

But in a smaller room with 100-200w…it will work fine.

Tom V.
SVS

i was planning to use the 300w monolith amp, but am not sure now, as tom says 100 - 200w should be fine

many thanks

paul

*banners* · 10-01-2007, 4:23 PM

Have you tried SVS for the amp? I doubt they'd sell as DIY but as a replacement? I'd have thought it's worth a try.

Oh and you can never have too much power IMO! Go for the 300 watt if you like, I use it in a DIY sub and it's cracking!!

Steve

stevefish69 · 10-01-2007, 6:29 PM

Quote:

Originally Posted by paulst10

steve ... any chance you could let me know the dimensions of the tube you are getting, as its got me thinking now ... cylinder or box .. hmmmn

Paul.

Tube inside diameter is 400mm
Tube length is 920
Wall thickness is 6mm
Price inc delivery is £53.18
MDF discs to fit inside tube is £5.34 each.

I believe that these are the same dimentions as my 20-39 PC+ but you can have a tube made to any dimension. Just fill in the form on their website. I got a reply the next day

Hope this helps. Not sure if i would try to mount the Amp module in the Tube, or in a seperate box with speaker cable attached.

Tube seems like the easiest design to copy, Just need to sort out the thick endcaps, mount driver and Ports, acoustic wadding and hey presto

*banners* · 10-01-2007, 7:31 PM

Steve, do you think that the 6mm thickness is sufficient?

It just sounds a little thin to me. I appreciate that a cylinder is a strong shape, but I'd have thought about double that would be a minimum IMHO.

Also what thickness are the MDF plates and are these for use as bracing?

Good luck to you both!

Steve

stevefish69 · 10-01-2007, 10:57 PM

Quote:

Originally Posted by banners

Steve, do you think that the 6mm thickness is sufficient?

I do not know how thick the Sonotubes are that SVS use. IIRC when i stripped my Cylinder down to changer the driver, it didn't look much thicker although i may be wrong.

Also there is only one reinforcing MDF disk in the SVS which can just about be seen surounding the Port tubes below. I have yet to ask Essex tubes the thickness of the disc.

I'd probably make them myself anyway out of 1" MDF for the Endcaps, bottom plate and support for within.

This will be a project for the summer, as SWMBO has put me on a spending ban after changing my fronts earlier this week

Maybe Our friends from SVS may pop in here and comment

suniil · 04-02-2007, 10:07 AM

me too planning to build one for my holiday home here

Its very hard to find sonotube in this region, but there are alternative products available i hope.

I've spotted a plate amp here, but it shows no longer manufactured

i've seen a thread refering to another european supplier a while ago, but now i failed find it here.

Quote:

Originally Posted by stevefish69

I am in the middle of getting the bits together for a bit of DIY myself.

Essextubes have just quoted me £55 delivered for a tube the same dimentions as my 20-39 so i may go down this route.

You'll find my thread on in the spot with some links to suppliers for Amp modules and Ports. Hope this helps.

http://www.hometheaterspot.com/htsth...e/0#Post818999

http://www.essextubes.com/

paulst10 · 04-02-2007, 12:32 PM

some usefull info appearing here

edit: does any know whether the the svs 12.2 & 12.3 drivers are 4ohm or 8 ohm ????

i am still waiting for my 12.3 driver (coming from the U.S) ... shouldnt be long now! although i probably wont start it until the summer.

in your honest opinion guys ... if you were spending say £300+ on building a DIY sub, what sort of performance could i expect from it ? and would it be worth while ? ...

i mean, some quality components are being thrown into this (svs 12.2 driver & monolith amp/back plate), could this sound as good as it should ? ...

or will it just turn out to be a fun experiment that gives you an average sub, that could be beaten on performance by a sub of similar value bought retail ??

i imagine a hell of lot will depend on the quality of the cabinet/cylinder (which is coincidently probably the hardest part of the experiment

)

should be laugh though

paul

Nimby · 04-02-2007, 12:47 PM

The reason SVS have suggested your design won't go super loud is because you are going to use a small box.

The 12.2 was used in a large ported box or cylinder. So here it wins the dB and LF extension war on all counts compared with a small sealed box.

The SB12+ may well use a special driver with an extended Xmax compared with the 12.2 to allow it to still go reasonably low and loud in a small sealed box.

Though still not as loud or as low as the much bigger ported enclosures.

paulst10 · 04-02-2007, 1:35 PM

cheers nimby

, although looking at the dimensions of the amp (H355 x W203 x D145mm) ... i think i may have to re-think the dimensions of the cabinet as the height of the amp is nearly 14"

so, its looking like bigger could be better ... never know, it could be an SVS monolith in the making

Resonance · 04-02-2007, 3:28 PM

I don't know whether you are planning a sealed box or a ported box, but here are a few thoughts.

If sealed, because it's a big driver, you have to consider that the pressure from the driver will cause the sides to flex unless they are carefully strengthened. A flexing box sounds terrible.

If you port the box, you will need to tune the port to a suitable frequency.

The size, shape and design of the box can have a huge impact on the resulting sound from the speaker.

Much has been written about the pros and cons of sealed and ported speaker cabinets and how to design them. A quick search turuned up these speaker calculators, for example:

http://www.mhsoft.nl/spk_calc.asp

One of the reasons SVS originally built their cylinders was to use the inherent strength to overcome flexing in the cabinet and reduce internal resonance.

On the other hand, you could just pick a few random sizes for your box, screw in the bits and see how it sounds.

**IronGiant** · 04-02-2007, 6:25 PM

Anyone planning a DIY cylinder may find this thread interesting:

MY STS build (Sono-tube-subwoofer)

Dave

Edit: I'd drop in around page 4 to start with.

suniil · 04-02-2007, 10:04 PM

OMG, still you remember this one! more than 2 years old

Quote:

Originally Posted by Regmarch

Anyone planning a DIY cylinder may find this thread interesting:

MY STS build (Sono-tube-subwoofer)

Dave

Edit: I'd drop in around page 4 to start with.

**IronGiant** · 04-02-2007, 10:41 PM

After Mat had finished his experiment and realised it was far too big for his room he gave me his completed shell in exchange for a chat and a 4 pack of beer.

You tend to remember things like that

It's perfect in my house...

Dave

suniil · 05-02-2007, 9:47 AM

dave, can you please let me know which plate amp you have it on the sub?

thanks

Quote:

Originally Posted by Regmarch

You tend to remember things like that

**IronGiant** · 05-02-2007, 12:55 PM

The BSBP100, the 100W one from BK Electronics, more than powerful enough for my needs.

Dave

paulst10 · 05-02-2007, 1:17 PM

Quote:

Originally Posted by Regmarch

After Mat had finished his experiment and realised it was far too big for his room he gave me his completed shell in exchange for a chat and a 4 pack of beer.

You tend to remember things like that

It's perfect in my house...

Dave

cor! its alright for some

http://matthew.augier.info/index.php...ofer%2F&page=2

looking at these pics ... it looks like a hell of a lot of work went into it, and a very good job he has done to

(if mine looked half as good as that i'd be over the moon)

paul

Nimby · 06-02-2007, 12:26 PM

Quote:

Originally Posted by paulst10

(if mine looked half as good as that I'd be over the moon)

It might look like one. It might even sound like one. But it's not a real rocket.

paulst10 · 06-02-2007, 6:50 PM

Quote:

Originally Posted by Nimby

It might look like one. It might even sound like one. But it's not a real rocket.

what? not even if i name it APOLLO ?

**IronGiant** · 07-02-2007, 1:33 AM

The tube I have, I'd only put it at Saturn 5 on take off... it's only a card board tube after all.

Somehow it shakes the concrete foundations...

iainsilvester · 08-02-2007, 1:49 PM

Most of the cost of a speaker is the enclosure, the drivers really don't cost much to an OEM, crossovers are actually simple. The amp is another matter, but you seem to have that covered. When you pay more for any speaker it is the construction rigidity you are paying for.

Rather than try to copy another design, I would build the most substantial regular shaped enclosure you can, go overboard with internal bracing and line with bitumen sound proofing pads. This type of construction is expensive for an OEM, but cheap and fun for a DIY'er with some time. I would also go for a sealed box, venting extends the bass for a given size but can be fraught with problems, and your amp/driver combination need to be fit and matched for purpose as your cone will have minimal damping. There is a real danger you will hear the port "chuffing" unless you know how to tune it.

Built solidly, your sub will sound great!