Sub Box Advice

[bestatchess]

I ordered the 11 KV.2 sub from www.edesignaudio.com and I am going to build a box for it this weekend. (I have received the amps & component speakers, but I am still waiting for the sub.)

The dimensions are:

Physical Data - 11Kv.2 Dual 2 ohm coals (4 ohm load)
150 - 500WRms
Mounting Depth 5.25"
Mounting Diameter 9.125"
Overall Diameter 10.125"

Sealed Box - .4 to .6 cubic feet.

Is it better to be .4 cubic feet or closer to .6 cubic feet?

I am just going to use the one sub to be driven by the TRU 2.100 having the following specs:

Model: T-2.100
Channels: 2 CH
Frequency Response: 10Hz ~ 45KHz ±1dB
Rated Power: 14.4 Volts DC
T.H.D.: < 0.05%
4 Ohm RMS: 100W x 2
2 Ohm RMS: 200W x 2
4 Ohm Bridged: 400W x 1
S/N Ratio: > 100dB
CH Separation: > 70dB
Input Sensitivity: 0.16mV ~ 4 Volts
Damping Factor: > 400

Also, is it better to have the sub cone opening forward, down, or up? I have noticed different people having subs with all of these variations. I think sammy had his facing forward and then changed to facing up. The OEM RF sub faces up and it sounds very directional to me (I think they set it up like that so it fools the driver on the test drive). But maybe that is not a function of which way it faces but of other properties of the sub?

I intend to put the sub under the driver's side rear seat in the CC. Any problems with that? I thought about trying to get it behind the rear seat, up against the back wall of the cab, but I don't think there is enough space in view of 5.25" + .75" MDF + .75" MDF = 6.75".

Finally, I was reading on the net and it was recommended in one article to sandwich two sheets of 3/4" mdf together for the face of the box with the mounting hole for added strength. Is that advisable or just a waste of MDF and potential box volume?

[smoketitan]

first of all wow you got your set quick!! thats cool

1) downfiring will spread the sound over the vehicle--upfiring will give you more directional sound volume IE it may be a little louder---and you dont need two sheets of mdf for the woofer as it .75 will be strong enough for a woofer of that size---just try and use some tnuts from home depot to mount the sub as they are a lot stronger than regular screws--see pic

and I so do want some of those tru amps I am jealous


oh how do you like the new ed components??

[pciley]

Originally Posted by bestatchess

Finally, I was reading on the net and it was recommended in one article to sandwich two sheets of 3/4" mdf together for the face of the box with the mounting hole for added strength. Is that advisable or just a waste of MDF and potential box volume?

I agree. You will not need two pieces of MDF sandwiched for the face. A subwoofer of this low of RMS power handling won't have any flexing issues if you use 3/4" MDF on a small box. If the face of the box was larger or the power handling greater, than this is a good idea.

Also, every installer will tell you something different... but in my experience, the more surfaces the bass frequencies have to bounce off of before reaching the listener, the better. For instance, you don't want a woofer pointed at your head. If you had a box in your trunk, you would want it to face the rear of the vehicle, slightly up towards the deck lid.
In our case, we are so limited due to space constraints. If someone were willing to sacrifice the back seat, you could build one hell of an SPL vehicle. But we need our back seats. So, with the woofers firing down, it will probably sound better as long as the box is properly anchored to the floor. This will sound much more tight.

As far as the .4' vs. .6 on the cubic foot question, why not build your box as small as possible.* Just make sure the magnet is .25" or more from the inside rear of the box when the sub is mounted. ** The little bit of flex might cause the rear of the magnet to contact if you are closer.

*If .4 cubic feet ends up being too small, you can ALWAYS add PolyFill to fool the subs into thinking your box is bigger.
If you build a .6' box, you will not be able to make it smaller (unless you cut it up and try again).

**Tip: If you have built your box to the tightest tolerances of the mounting depth specs, and you are not sure if the sub magnet contacts or how far it is from the inside of the rear of the box, place a small chunk of clay or silly putty on the area of the bottom of the magnet most likely to contact the inside of the box and press the sub all the way onto the box as if it were being screwed down. Pull the sub out. Peel the clay off carefuly as to preserve its width and you will be able to see how far the magnet is or if it is contacting the box inside.

[bestatchess]

Originally Posted by smoketitan

first of all wow you got your set quick!! thats cool

1) downfiring will spread the sound over the vehicle--upfiring will give you more directional sound volume IE it may be a little louder---and you dont need two sheets of mdf for the woofer as it .75 will be strong enough for a woofer of that size---just try and use some tnuts from home depot to mount the sub as they are a lot stronger than regular screws--see pic

and I so do want some of those tru amps I am jealous


oh how do you like the new ed components??

O.K., cool. I think I will go with down firing for my single sub, as I have had enough of the Rockford Foster blasting my keister with distortion to last me for awhile as far as the "directional" effect.

What do you think about the volume of the box? .4 or .6 cu. ft. is the recommended range for a sealed box. Would you go more toward .4 or toward .6?


I have access to a nice wood working shop this weekend, so I am going to make the box and a carpeted mounting panel for the amps for behind the rear seats. (Yeah, I know this has been done before. Slavish copying serves me well. I take pride in knowing what to copy.)

Everything looks great, arrived promptly in fine shape. The amps are quite substantial in size & weight. I am still waiting on bquiet for the brown bread, and the 11KV2 sub from edesignaudio.com I wasn't really paying close attention when I ordered. It seems the amps & components had immediate availablility, but the sub was a pre-production order item. (it even says this on their web site) Hopefully the sub will be along shortly.

Thanks again.

[bestatchess]

Originally Posted by pciley

As far as the .4' vs. .6 on the cubic foot question, why not build your box as small as possible.* Just make sure the magnet is .25" or more from the inside rear of the box when the sub is mounted. ** The little bit of flex might cause the rear of the magnet to contact if you are closer.

*If .4 cubic feet ends up being too small, you can ALWAYS add PolyFill to fool the subs into thinking your box is bigger.
If you build a .6' box, you will not be able to make it smaller (unless you cut it up and try again).

**Tip: If you have built your box to the tightest tolerances of the mounting depth specs, and you are not sure if the sub magnet contacts or how far it is from the inside of the rear of the box, place a small chunk of clay or silly putty on the area of the bottom of the magnet most likely to contact the inside of the box and press the sub all the way onto the box as if it were being screwed down. Pull the sub out. Peel the clay off carefuly as to preserve its width and you will be able to see how far the magnet is or if it is contacting the box inside.

O.K., I think I understand. I am going to go with downfiring. My understanding is that would involve having a downwardly facing peripheral lip or ledge that contacts the floor, while the rest of the downward face is recessed a bit. Is that correct? How deep should the face be recessed?

As far as "properly attached to the floor" what does that involve? I was hoping just to size the box to be clamped down by the rear seat, when folded to a down position. Do I need to make some brackets to attach the box to the bolts that mount the seat to the floor?

I don't actually have the sub (I have access to a great shop this weekend, but the sub is not here yet), I am just working from the posted mounting depth and diameter. So I think I can leave a little extra space for the magnet.