Musical sub with 12" Infinity 1260W

[Sylar]

Decided to take the plunge and build a sub. On jinjuku's recommendation, have choosen to go along with the Infinity 12" 1260W driver.
Would like some help on how to proceed building it. Size is not really a constraint.

What I am looking for is a tight musical sub which is powerful

I know this is a long shot, but If possible, would be nice if the the sub could produce the same output - quality & power alike, with lesser power consumption.

 

[dpc]

I built a pair using the specs provided by jinjuku in this thread and these 300 watt BASH plate amps and am very happy with them. The bass response was a little uneven with one sub in my room, but with two it evened out the response well in my room.

We watch a lot of movies, and use them for music quite a bit as well and I'm very happy with them for both.

They go as loud as I care to turn them up without issue. I noticed you said you didn't want a boomy sub in another thread. I went from a 10" Klipsch that sounded boomy to the two of these and they go much deeper and don't sound boomy at all to me. I also found (in my room at least) that the Klipsch sounded a little more boomy to me while in the corner, so placement may make a difference for you as well.

These were my first builds and with my brother in law's help with the wood work (and his tools), I didn't think it was a tough first build even with the ported design. I imagine a lot of that is that the cabinet measurements were provided in the thread linked above, so I didn't have to become an expert at modeling tools.

So I'd say to take a look at those plans and see if it looks like a good fit for what you're wanting.

 

[jinjuku]

Here is the 80 liter (3 cubic feet) pdf attached.

My build thread...

 

[Sylar]

Here is the 80 liter (3 cubic feet) pdf attached.

My build thread...

Thanks for the design.

A few questions.
1. What is Flush Mounting?
2. Driver Mounting - All drivers face same direction. Does it mean both drivers face outwards?
3. Do I need to add internal baffle? If yes, how many? The supports (braces) for baffles (baffle to front/back), what thickness should it be? (In yours you have 1 baffle and 3 + 3 braces for it)
4. Would adding baffle & braces change volume calculations? Is current volume calculated for without them? By adding them should I rectify sizes to rectify volume?
5. To hold sides together, is it recommended to use nails or screws?
6. For sub connection, what do I use? Do I need to box up the inside of the connector or just let it be?
7. The driver does it need to be located at exact center of front and back panels?

It would be great if you have any link where it shows a step by step process how someone has done it.

Edit: I found some enclosure building tips here, something better, more detailed would be great. If possible.

 

[jinjuku]

1 Driver is flush with the baffle.
2 Both drivers are conventionally mounted outwards
3. My build has the dado'd baffle. When I get a chance there will be a cosmetic baffle overlay where the driver will be flush.
4. My box is a bit over 3cu ft (3.2 actually) to make allowance for bracing as you see.
5. I used dado's a glue. Brads for the braces that you see tying the baffles to internal window brace.
6. Standard terminal cup from Parts Express
7. most definitely yes. Just cut the inset baffles at the same time and set your center point. You can simply draw a line from corner to corner and where they intersect you have it. Draw your circle and hit it with a jigsaw.

The cosmetic baffle you will want to use a circle jig and router with spiral upcut bit.

 

[Sylar]

1 Driver is flush with the baffle.

I still didnt follow what you meant. I am not familiar with this terminology.

3. My build has the dado'd baffle. When I get a chance there will be a cosmetic baffle overlay where the driver will be flush.

What is a dado'd baffle and whats a cosmetic baffle overlay?

My box is a bit over 3cu ft (3.2 actually) to make allowance for bracing as you see.

will calculate and post my new dimensions to compensate for braces

 

[jinjuku]

Flush means level with. Dado is simply removing 19 mm wide by 10 mm deep channel of wood that the panel will notch into.

If you look at my build thread you should be able to see how the panels are joined.

The cosmetic baffle is one that is simply routed out to a diameter that is about 1/16th larger than the driver and simply gets glued on. You could cut and finish it first and then glue it on. The pictures in the build thread should get you close. Just figure a 3.2 cubic foot cabinet and then do the bracing as you see. You will be darn close to 3.0 (80 liters).

 

[darien87]

Thanks for the design.

A few questions.
1. What is Flush Mounting?

To do flush mounting you will need to compose the "face plate" that your woofer is mounting to out of 2 pieces of wood that are attached to each other. The flush panel will have a larger circle cut than the mounting panel. It's a little bit hard to describe but hopefully these pics should help. The driver in my Rythmik sub is flush mounted.

Here's a pic of the 2-piece mounting panel

See how the inner "ring" of wood is smaller diameter than the outer ring? The driver mounts to this inner ring while the outer edge of the sub fits inside the outer ring.

Notice how the edge of the driver fits "flush" with the bottom edge of the box? That's why they call it flush mounting.


Now the driver on my CSS sub is NOT flush mounted. The driver is just bolted directly on to the face panel. It just depends on if you like the flush mounted look or not.

Does that help?

I used nails AND screws in my Rythmik sub as it was my first DIY and I thought I needed to attach the hell out of the panels. I used glue only in the CSS sub as I learned the screws were unnecessary. If I had it to do over again I wouldn't have bothered with the screws on the Rythmik sub. In addition to them being unnecessary, you'll have to cover them up with putty or something when you go to finish the sub.

 

[Sylar]

To do flush mounting you will need to compose the "face plate" that your woofer is mounting to out of 2 pieces of wood that are attached to each other. The flush panel will have a larger circle cut than the mounting panel. It's a little bit hard to describe but hopefully these pics should help.

Yup, this helps
I was going to use one piece of wood 2 mm thickness and try to carve up 1 inch deep and width as much as the driver needed to rest upon. Which is not straightforward for a first timer. The only way i could think of achieving this efficiently was using some kind of a power tool.
Using 2 planks, is much easier and saves the hassles, by just using another another plank on top of a front mount.

I used nails AND screws in my Rythmik sub as it was my first DIY and I thought I needed to attach the hell out of the panels. I used glue only in the CSS sub as I learned the screws were unnecessary. If I had it to do over again I wouldn't have bothered with the screws on the Rythmik sub.

I was wondering how hard is it gonna be get an airtight enclosure. Trying to keep the build as simple as possible, and use the effort in some kinda creative finishing.

 

[caper26]

I simply cut 2 pieces the same size for front baffle. Inside piece to mount driver, outside to allow the flange to fit inside, rounded over the edge, then glued them together. You will notice in the last photo, the driver is 'flush' , and the passive radiators on the sides are 'surface' mounted.

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The front driver looks like it is 'sunk in'. here is the build ALBUM.

 

[Sylar]

i checked around for prices and availability all parts.
MDF is available only in thickness of 18mm and next is 25mm. 0.75 inch equates to 19mm. I presume 18 mm instead of 19mm is not an issue? Or do I need to be that precise?

Also, a friend back home suggested that I go with 25 instead, and make it heavier.

 

[Sylar]

i calculated to compensate for braces and baffle.

Internal volume comes to 84.36 litres (older was 84.43) (Calculation excluding driver cone protruding inside and connection terminals)

New dimensions:

Box:
Height: 19.5, Width: 19.5, Depth: 19.85

Baffle (One):
Height: 18, Width: 18, Thickness: 0.75

Braces (Six):
Length: 8.8, Width: 5, Thickness: 1.5

Thinking of making an inner box for the connection terminals, something like this - smaller.

 

[jinjuku]

That all looks good and 18mm MDF if perfect.

 

[caper26]

yeah 18mm is just fine.

 

[Sylar]

17 mm thickness MDF is what I was able to get hold of.
Still looking out for 18 mm thickness.

 

[Sylar]

What gauge wire is recommended?
I have some 16 gauge wire left over. I had a look at this recommendation, and looks like it should be fine for internal box wiring which is around 3 ft.

But external what do I use? Wiring from amp is 15-25 feet one way. Since load is 2 ohms, From the chart I infer that even 14 would not suffice. So should I go 10 or 12 gauge for this ?

 

[panteragstk]

For internal wiring you should be good. External I'd grab some 12ga and be done with it. I actually used 12ga in my whole system just because of the minimal cost difference.

 

[Sylar]

One box is almost completed. Have to make holes for the driver, and a little work on bracing support. Another two are half way through. Has come out pretty well so far.

Would like to know if I would need to use Polyfill?
I understand that this is basically to increase the 'apparent volume of the sub' by slowing down the sound waves.

 

[jinjuku]

One box is almost completed. Have to make holes for the driver, and a little work on bracing support. Another two are half way through. Has come out pretty well so far.

Would like to know if I would need to use Polyfill?
I understand that this is basically to increase the 'apparent volume of the sub' by slowing down the sound waves.

~12 - 16 Oz per cubic foot.

 

[GranteedEV]

Would like to know if I would need to use Polyfill?
I understand that this is basically to increase the 'apparent volume of the sub' by slowing down the sound waves.

Poly fill will not slow down sound waves. However it can convert 30 to 90% of the rear wave higher up in frequency into heat.. which can lead to a bit more clean sound....possibly.

Just don't over-do it as you will start to lose port output.