how to make your own fathom

[metalrake]

hi,
i've been going through these forums for hours. i'm convinced i can make a sub now. i want to make something similar if not exact to the 12" fathom. so far i've got that i need the w7 12" driver, EP2500, DCX2496, 3/4 " hardwood plywood.

i'd rather build my own box, instead of purchase one and just cut a hole for the speaker.

i wish it to be about the same size as the actual fathom because i have little room.

how would i go about building this box?
what dimensions?
sealed?
how do i brace inside?
what do i use to connect everything?
mount amp where?
what setting on dcx2496?

is there a thread that has this info that someone can guide me too?

thanks,
sean

 

[TLS Guy]

hi,
i've been going through these forums for hours. i'm convinced i can make a sub now. i want to make something similar if not exact to the 12" fathom. so far i've got that i need the w7 12" driver, EP2500, DCX2496, 3/4 " hardwood plywood.

i'd rather build my own box, instead of purchase one and just cut a hole for the speaker.

i wish it to be about the same size as the actual fathom because i have little room.

how would i go about building this box?
what dimensions?
sealed?
how do i brace inside?
what do i use to connect everything?
mount amp where?
what setting on dcx2496?

is there a thread that has this info that someone can guide me too?

thanks,
sean

By the look of this you are nowhere near ready to build a sub, especially not that one!

That driver is designed to be placed in a sealed box. However it only goes to 48 Hz. Now these drivers have massive motor systems. They are only three ohms. The amp that drives them is 1500 watts. To get the F112 Fathom to have an F3 of 19 Hz, massive amounts of EQ are applied, and I'm pretty sure they use servo feed back.

This is not a beginner project, no small sub is.

Take a look at this thread from this morning.

To see how to build an enclosure take a look at the kappa perfect 12 build threads.

 

[WmAx]

By the look of this you are nowhere near ready to build a sub, especially not that one!

That driver is designed to be placed in a sealed box. However it only goes to 48 Hz. Now these drivers have massive motor systems. They are only three ohms. The amp that drives them is 1500 watts. To get the F112 Fathom to have an F3 of 19 Hz, massive amounts of EQ are applied, and I'm pretty sure they use servo feed back.

This is not a beginner project, no small sub is.

Take a look at this thread from this morning.

To see how to build an enclosure take a look at the kappa perfect 12 build threads.

Actually, the Fathom used massive EQ to the same effect. The W7 driver has such massive linear excursion that it can be used flat to the low 20's with high output and relatively low distortion at substantial SPL, if one uses an amp of suitable power. It is far from the average subwoofer driver in terms of both linearity, excursion and thermal dissipation; therefor it can be used with massive EQ with no problem as long at one has enough power on tap. The EP2500 is sufficient for power and the DCX2496 unit will allow the required response shaping to get a flat LF response in the tiny sealed box.

BTW, the JL W7 drivers may claim 3 Ohms, but I don't think this is an accurate specification. I have some 8" W7s that claim to be 3 Ohms. In reality, they are nominally, about 3.9 Ohms, after analyzing actual impedance plots. Annukai, a member here, drives his W7 12" with an bridged EP2500 and it works perfectly.

-Chris

 

[WmAx]

hi,
i've been going through these forums for hours. i'm convinced i can make a sub now. i want to make something similar if not exact to the 12" fathom. so far i've got that i need the w7 12" driver, EP2500, DCX2496, 3/4 " hardwood plywood.

i'd rather build my own box, instead of purchase one and just cut a hole for the speaker.

i wish it to be about the same size as the actual fathom because i have little room.

how would i go about building this box?
what dimensions?
sealed?
how do i brace inside?
what do i use to connect everything?
mount amp where?
what setting on dcx2496?

is there a thread that has this info that someone can guide me too?

thanks,
sean

1.5 net cubic feet is plenty of volume for this driver sealed. Since the box will be so small, and the driver's motor is so large, the only kind of bracing you can use is shelf braces with large circles cut in the center of them to let the driver motor have clearance. Or just make the box out of 2 layers of hardwood birch ply (1.5" total thickness) and no bracing at all is needed for this small cabinet.

As for specific setting on the DCX2496, you need to provide the actual T&S parameters for your driver and I can recommend the proper settings. Ideally, you should measure the T&S parameters of the actual driver you own using a tool like the Dayton Woofer Tester 3.

-Chris

 

[annunaki]

Hello.

Please see my build thread below in my sig (Build Thread 2).

I have added a DCX2496 to the Behringer EP2500 and it works wonderfully. Though I have not yet tested it since the addition of the eq. I should be near ruler flat from around 17hz-80hz at my listening position. The 2496 is everything you want in a processsor and then some. I am confident that I can tweak my setup in more detail than any of JL's options.

It sounds phenomenal and very, very accurate. Since adding the eq (to tame room modes) I am hearing things in the music I hadn't before, even when I had my SYS PB-12 Ultra.

Total equipment cost: $986.00 Build materials: $35.00

I will be refinishing the enclosure sometime this spring so it looks better in the house. Other than that, I will be keeping it for quite some time!

 

[Hipnotic4]

I have some 8" W7s that claim to be 3 Ohms. In reality, they are nominally, about 3.9 Ohms, after analyzing actual impedance plots. Annukai, a member here, drives his W7 12" with an bridged EP2500 and it works perfectly.

-Chris

Love those 8s..always impressed me

 

[metalrake]

thanks for the help,
the bracing in your pics looks good, just a little confusing.

"shelf braces with large circles cut in the center?"

can you elaborate on this wmax(chris)? does this mean triangles for each corner?
if i put a peice in the center and cut a hole so the driver motor doesn't touch it is that ok? do all sides of box need bracing?
thanks,
sean

 

[annunaki]

All six panels of the box should be braced with no more than 7 inches square unbraced at any point. All of the bracing should tie together as well.

My W7 enclosure was one of my first more intricate attempts at solid bracing technique. All of the cuts and such are purposeful. I wanted the strongest bracing system possible without sacrificing much internal displacement.

 

[metalrake]

ok thanks,
i'll just copy all the braces you used, but i'll have to make the box deeper and less wide to fit where i want it.

thanks,
sean

 

[metalrake]

hi,
will you tell me what type of wire to run from the speaker to the terminals? and what type of terminals?...do you guys have an online store you recommend and a size you recommend for my application. also what size wire do i run from the terminals on the back to the amp/eq so maybe i can buy all the little stuff at once.

thanks,
sean

 

[jamie2112]

This is a great place to buy stuff http://www.parts-express.com/home.cfm?CFID=590623&CFTOKEN=44947539

 

[annunaki]

I used 10 ga. speaker wire to avoid any issues. It is plenty large enough for the application. 12 ga. would also be acceptable. I would not go smaller though with the amount of power available. The length is also important to keep in mind.

 

[annunaki]

ok thanks,
i'll just copy all the braces you used, but i'll have to make the box deeper and less wide to fit where i want it.

thanks,
sean

Sean that is fine. You will want the net volume to be around 2.15ft^3 - 2.25ft^3. This allows the flattest anechoic response prior to EQ.

With my room mode corrected, it is sick how accurate that woofer is, not to mention effortless.

 

[metalrake]

what size hole do i cut to mount to w7 12"

 

[metalrake]

http://s617.photobucket.com/albums/tt260/metalrake/?action=view&current=randomsprkbox031.jpg

 

[metalrake]

 

[metalrake]

 

[metalrake]

having trouble getting the image on there...this is was i have so far...i just cut holes to make it simpler...if this isn't going to work well please let me know

 

[Matt34]

There ya go.

 

[annunaki]

http://s617.photobucket.com/albums/tt260/metalrake/?action=view&current=randomsprkbox031.jpg

Sean you will want to brace the rear panel of the enclosure. The bracing you have so far should be adequate for the center panels. Ideally your bracing scheme ties all 6 panels together quite solidly.

Brace your front & rear panels & you'll be set.

Mounting hole diameter is 10.5" (10-1/2").