Voxel - a mini-sub+

[Millstonemike]

Well, if I can get them to upload, here is the proof of build. I am not too pleased with the cosmetics. Every joint shows, despite white glue impregnation and many coats of shellac but it stays under the desk and sounds great.

A bane of many builders despite the many threads and solutions on TT. But it looks good in the pictures.

[Chemacky]

Does anyone know of an equivalent amp to the recommended one here that has a remote? I feel like it would be an infinitely useful addition to this set-up in use with a small home-theatre type set-up.

[Scarface1]

I brought this project to InDIYana 2013, but never put any info out there about it. A thread a few days ago asking for a small sub prompted me to get myself in gear and post the plans.

I designed the sub around http://www.parts-express.com/pe/showdetl.cfm?partnumber=310-308"]this amp[/URL], although obviously any sub plate amp will work (depending on how creative you want to get mounting it to the somewhat small enclosure). Is this amp truly 68 Watts? Probably not, however it has the neat bonus of allowing you to add bookshelf speakers to create a 2.1 setup.

The only other things you need to do this project are:

• http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-917"]TB W5-1138SMF[/URL] (great little workhorse)
• 2 of http://www.parts-express.com/pe/showdetl.cfm?partnumber=260-402"]these vents[/URL], glued end-to-end
• 1/2" plywood or MDF.

[ATTACH=CONFIG]38849[/ATTACH]

The approximate volume of the enclosure is around 7 Liters, and it should reach an F3 of 35 Hz. I don't have an exact number for the max SPL, but in theory it should be able to get to 98 dB before the amp runs out of steam. The port diameter may be the weakest link here, and would probably chuff pretty bad if pushed any harder. That driver, it just goes and goes; this is the kind of thing it was meant to do.

Can i use a different model with this sub. I calculate your inside volume of the box and that is 7,8 liter. I want to build a 2.1 portable speaker with this subwoofer but whit a other form. Is it stil the same sound or does that chance?

[Millstonemike]

Can i use a different model with this sub. I calculate your inside volume of the box and that is 7,8 liter. I want to build a 2.1 portable speaker with this subwoofer but whit a other form. Is it stil the same sound or does that chance?

The form factor of the 7.8 liters is not very critical (within reason) as long as the sub has it's own chamber in the overall design. Make sure the inside open end of the vent has enough space between a wall (>1.5") - elbows are okay.

[Scarface1]

Tanks bud !!

[Scarface1]

If i buy the bass port on parts express it wil cost me 30 dollar. Do somebody know if i can a different bass port and if its possible with a 90 degree curve in it!!

I bought the speaker already

[Millstonemike]

If i buy the bass port on parts express it wil cost me 30 dollar. Do somebody know if i can a different bass port and if its possible with a 90 degree curve in it!!

I bought the speaker already

PVC at the big box hardware stores. My HD sells 2' sections and, of course elbows. The actual inside diameter of 1.5" PVC is 1.61", slightly larger than the true 1.5" of the recommended ports. So plan on it being a tad longer. The elbows length is measure from the middle of the diameter end-to-end to get its length.

The elbow will everything together for testing so yo can experiment with different lengths. Some use only duct tape for the final install (I used nothing, press fit).

And remember, you can always cut it shorter - but not longer. But you should have enough with a 2' length plus the elbow for have several attempts.

[Chris Roemer]

You can buy PVC (plumbing) pipe, and get an elbow for it.

[Scarface1]

Tanks guys i really really apriciate this. I don't have a pc but ask a friend if he wil calculate the new adjustments for me.

1 thing to say and it is not mean to be a jerk but why is the voxel sub so special. If you put the driver in a speaker design program it will also design a box for you about 7.4 liters with very low bass.

So is there a difference i don't get or see. I really want to know and also it not meant to be offensive.

Greets

[Kevin K.]

Tanks guys i really really apriciate this. I don't have a pc but ask a friend if he wil calculate the new adjustments for me.

1 thing to say and it is not mean to be a jerk but why is the voxel sub so special. If you put the driver in a speaker design program it will also design a box for you about 7.4 liters with very low bass.

So is there a difference i don't get or see. I really want to know and also it not meant to be offensive.

Greets

What makes the Voxel sub "special" is the combination of "off the shelf" parts and how low the driver will play in such a small enclosure. Paul published this design using two of the Goldwood 1-1/2" ports taped end to end, no length modification necessary. The smaller amplifier he chose was a good match because of the x-max limitation of the driver in the published enclosure. In other words, his design could be built with a minimum amount of tools, stock parts off of PE's shelf, and since it was so simple, you didn't need a lot of cabinet building experience to build it. Minimal tools required.

Depending on your skill set, you could build the Voxel as is or you could stray from it a little and try other amps and/or pvc ports. Keith is working on one in the Speaker Project Gallery now if you're interested. Here is a link to it: http://techtalk.parts-express.com/fo...-with-sa70-amp

[Scarface1]

thanks a lot. I have bought some pvc pipe and there is told me that i have to measure the middle of the pipe. Now if i look inside the pipe i see there is a small ler point so how do i go with this.

[Scarface1]

Also i want the vent forward of the speaker so that the air goes in the same direction as the speaker air( so i can place the speaker near an object without strange bass reflections).

On the left and the right of the subwoofer i will place full range speakers so i have from left to the right-->

Fullrange->subwoofer->vent hole->full range

Do i have to look out for something, the distance of speakers, because of the vent hole it's not symetric anymore. So my question is how do i place the speakers (distance)

[KEtheredge87]

thanks a lot. I have bought some pvc pipe and there is told me that i have to measure the middle of the pipe. Now if i look inside the pipe i see there is a small ler point so how do i go with this.

When considering a run of pipe (or in this case a port for your cabinet) you need to measure the center line distance of the pipe including any bend radii. A pair of calipers would probably help you measure the ID of that elbow at the internal shoulder. From there, consider the length around the bend as one quarter of a circle. So, circumference of a circle is calculated by 2*pi*r, where your radius will be 1/2 of the ID that you have inside that elbow at the shoulder. You may need to add a little length (~1/8"?) to account for the extra length between that curved path we just calculated and the actual start of that pipe shoulder. Sent from my SM-N900V using Tapatalk

[Scarface1]

Does somebody know how to calculate the volume of the speaker. I now have a 7.5 liter enclosure but i think the speaker volume and the bass pipe volume also counts so i have to add the volume by the speaker enclosure.

Example--> calculated box enclosure = 7.5 liter
Speaker = 600ml
Bass pipe = 400ml

So my total volume of the enclosure must be 8.5 liters!

But how do i know the speaker volume?

[Chris Roemer]

I'd mostly just worry about the magnet on THAT one, about 0.3L. Probably won't change the box model much whether you include it or not this time.