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Discussion Starter · #1 · (Edited)
Hi guys just thought I would share my newest little sub project.The design is similar to BAG END's ELF but the dual integrator control unit is Rod Elliots design.http://sound.westhost.com/project48.htm The box is a 14" cube (22 litres net) and the woofer is a 12" Infinity car driver.The pictures show the partially completed box and the finished controller.

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Discussion Starter · #3 ·
Thanks Jack , my lovely wife bought me that saw for Christmas a few years ago and it works great.

The design is based on the project by Rod Elliot that I linked to.It is essentially the same as BAG END's ELF http://www.bagend.com/ but without the concealment circuit.I built the control unit as per the article but did some minor changes to suit my setup better.

I wanted to add another sub for my LFE channel for those demanding action movies but it had to be compact so thats why I chose this design.The promise of below 20hz bass in a small sealed box had to be worth a try.

The woofer is an Infinity 1230w car woofer and was chosen because it was inexpensive(but quite well built )and fit the design perfectly.I will be powering it with an ICE power 250asp classD amp 250w into 4 ohms.
 

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The design is based on the project by Rod Elliot that I linked to.It is essentially the same as BAG END's ELF http://www.bagend.com/ but without the concealment circuit.I built the control unit as per the article but did some minor changes to suit my setup better.
Yeah, Rod's got some great stuff on there. I was wondering what you wound up with as the starting Fc of the box and what you chose as your shelving frequency?
Why did you choose this over something like a Linkwitz Transform?
 

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Discussion Starter · #7 · (Edited)
Yeah, Rod's got some great stuff on there. I was wondering what you wound up with as the starting Fc of the box and what you chose as your shelving frequency?
Why did you choose this over something like a Linkwitz Transform?
The Fc of my box /woofer combo is in the 60hz region.I used the published component values so the boost begins to take effect in the low 60's reaching maximum boost of about 14db at 20hz. I also incorporated the filters (2k7 res and 4.7uf caps) so that the response below 16 hz is rolled off.

Why use this instead of an LT? In a word simplicity.The LT requires more presicion and tweaking to get right and requires the use of a low pass filter of some sort.Also to get the same kind of bass extension with this woofer in this small a box would require even more boost from an LT.
 

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Discussion Starter · #9 ·
what would stop you EQing this kind of sub with a bfd? would that be posible?

edd
Do you mean use the BFD in place of the circuit I am using or in conjunction with?
While you certainly could use the the BFD instead to add bass boost, it would be much preferable to use the intended circuit.This because it is precisely taylored to give the correct amount of boost.The BFD could be used in conjuction to smooth out the in room response.
 

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yes i meant instead of the elf circuit. i understand its far from perfect but it would be a way to test the elf sub if you have a spare driver or 2 :R

what intersts me with the elf system, is that the small box causes a roll off, which you equalise out. whats to stop you equalising any roll off in a sub? why does throwing more voltage at the driver actualy work in this case, is because the roll off has little to do with the driver and more to do with the small box?

i remember reading the esp article quite some time ago, i may have to build one out of some spare drivers i have lying about.

edd
 

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Discussion Starter · #11 ·
yes i meant instead of the elf circuit. i understand its far from perfect but it would be a way to test the elf sub if you have a spare driver or 2 :R

what intersts me with the elf system, is that the small box causes a roll off, which you equalise out. whats to stop you equalising any roll off in a sub? why does throwing more voltage at the driver actualy work in this case, is because the roll off has little to do with the driver and more to do with the small box?

i remember reading the esp article quite some time ago, i may have to build one out of some spare drivers i have lying about.

edd
Hi edd
You could EQ the rolloff of any sealed sub(ported designs usually don't need the help) but of course this puts greater demands on the driver and requires more power.A driver in a sealed box will roll off at a rate of 12db per octave below the system resonance or Fc.The Fc is determined by the combination of the drivers T/S parameters and the box volume.A smaller box will move Fc to a higher frequency so the start of the roll off is higher as well.

The ELF circuit boosts bass below Fc at at rate of 12db per octave thus exactly countering the drivers roll off therefore extending the response.My decision to use the ELF/EAS was because I wanted a very compact enclosure. This resulted in a Fc(60hz) which is much to high to be of any use without EQ.

If I were going to EQ using a BFD or LT and had the room I would want to start with a bigger box so that the Fc was maybe more like 40hz.

Does my little ramble help any?
 

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yes thanks, basicaly the roll off starts at 60 db, throwing more voltage at a driver in this region wont stress it to much, do it at 15hz and you can run into trouble :R

i have 2 12 inch car bass drivers, it may be fun to build an elf sub with these, i can mess with the bfd to give an idea if i actualy like the sub before making the circuit.

This is only to mess around with, ive already ordered a new sub in a fairly large box, i have the room :bigsmile:

by the way your speakers look amazing.

edd
 

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Discussion Starter · #13 ·
Almost ready to test then I must decide on the finish.
I was originally going to do a gloss piano black but now I think I will use veneer instead because it will be a better match with my furniture.


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Almost ready to test then I must decide on the finish.
I was originally going to do a gloss piano black but now I think I will use veneer instead because it will be a better match with my furniture.
Now, it may just be me, but you JUST can't build your sub/speaker and go with such a vanilla skin as piano black! :hissyfit:

Seriously, for me, that was one of the best things about building my own speakers was that I could skin them in something NOONE else had. It's a little more work, but it looks so much better.. at least to me. :innocent:

BTW, nice work on the sub and you've got a cute daughter(?).

JCD
 

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Discussion Starter · #15 ·
Now, it may just be me, but you JUST can't build your sub/speaker and go with such a vanilla skin as piano black! :hissyfit:

Seriously, for me, that was one of the best things about building my own speakers was that I could skin them in something NOONE else had. It's a little more work, but it looks so much better.. at least to me. :innocent:

BTW, nice work on the sub and you've got a cute daughter(?).

JCD
I picked up some Maple veneer today.I'll save the piano black for my computer speakers.

BTW my daughter says thanks.
 

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Discussion Starter · #19 ·
Looks awesome from here. :clap:

Of course, now we need to know what stain, if any, you'll be using.

JCD
Thanks
funny you should mention the stain because I just checked out the thread on the awesome speakers you built and was going ask what stain you used.I like the look of natural maple but it is too light coloured to match anything.

btw your speakers look fabulous and the drivers are top notch as well.Was that your first DIY speaker?
 

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Thanks
funny you should mention the stain because I just checked out the thread on the awesome speakers you built and was going ask what stain you used.I like the look of natural maple but it is too light coloured to match anything.

btw your speakers look fabulous and the drivers are top notch as well.Was that your first DIY speaker?
Hmm.. I THINK the stain was Sedona Red. I wouldn't bet my life on it, but that's what I recall. Also, the wood itself is a lacewood veneer, therefore it's gonna start off a little bit darker than your maple. My local hardware store sold samples for ~$0.50/each. I bought about 6 different colors and tested them on some of my scraps before I settled on the final stain..

And thanks, I like them a lot too. I just wish my garage was cleared out better so I could set up my listening room down there. Hopefully soon.

And yeah, those were my first. It was a kit that was offered on Zalytron.com. They've since stopped selling Usher drivers, so the kit is no longer available -- the new Usher driver online store, Parts Express, doesn't have a kit yet that uses Usher drivers. Or at least I haven't seen one.

JCD
 
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