Voxel - a mini-sub+

[warllo]

barrymossel Hi, The setup has been working great with the parts I listed in my original post. I think it's plenty loud and I think it pushed the woofer to excursion. I also made my Voxel Passive and active so I that I would have more amp choices I didn't use the crossover however. The crossover you posted looks very similar to the one that PE sells which needs modification to work correctly so be careful with that. If you go to the reviews for the PE part a very nice forum member by the name of Millstonemike posted a guide on how to modify it so it works as advertised. I have not tested it but it seems like a very thorough write up. Hope this helps and enjoy your Voxel. It's a fantastic little beast.

[entomophile]

Thanks Paul C for the design and thanks to tomzarbo for recommending the voxel. Got it built up and ready to rock! Looks were not important as it is going inside a vintage cabinet.

[barrymossel]

barrymossel Hi, The setup has been working great with the parts I listed in my original post. I think it's plenty loud and I think it pushed the woofer to excursion. I also made my Voxel Passive and active so I that I would have more amp choices I didn't use the crossover however. The crossover you posted looks very similar to the one that PE sells which needs modification to work correctly so be careful with that. If you go to the reviews for the PE part a very nice forum member by the name of Millstonemike posted a guide on how to modify it so it works as advertised. I have not tested it but it seems like a very thorough write up. Hope this helps and enjoy your Voxel. It's a fantastic little beast.

Ah, you mean this thread: http://techtalk.parts-express.com/fo...re-amp-exposed
It looks indeed as the same board. C5 and C6 are also the values that need to be replaced. I guess I can make those modifications, though my soldering skills aren't that good :(

[RexDog]

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 this amp, 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:

• TB W5-1138SMF (great little workhorse)
• 2 of these vents, 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.

Hello,
I just built this box (one of my first ever builds) and am powering it with the same Lepai 2.1 amp using the power supply that came with the amp. Can I ask how much you are able to turn the sub volume up with your amp? I can barley turn sub volume up off the minimum setting (less than 25%) without the subwoofer sounding really bad. Also, the crossover does not seem to do much. I don't know if I got a bad subwoofer or if there is a problem with my amp. I'm leaning towards an issue with the amp since crossover seems to do very little.

Thanks,
Daryl

[Brian Steele]

Hey, I've been simming an MLTL layout for the TB driver used in the Voxel to see if I can come up with the same or similar box volume and performance. The results of the sim look pretty interesting, suggesting that the design can take up to 120W and produce about 102 across its passband before the driver exceeds excursion in the passband, and even with a 1.5" diameter vent, chuffing should not be readily audible. For those of you who have built the Voxel, has that been your experience?

[ceiol]

Hey, I've been simming an MLTL layout for the TB driver used in the Voxel to see if I can come up with the same or similar box volume and performance. The results of the sim look pretty interesting, suggesting that the design can take up to 120W and produce about 102 across its passband before the driver exceeds excursion in the passband, and even with a 1.5" diameter vent, chuffing should not be readily audible. For those of you who have built the Voxel, has that been your experience?

I tried playing around with your MLTL excel sheet for the TB W5 driver, but didn't really succeed -- it would be great to have your direct input and expertise behind it.

I've made a couple of voxel subs -- there is some port noise at higher levels, even with using the two 1.5" flared ports back to back as recommended.

[Brian Steele]

This is what I've come up with at the moment. the net box volume is slightly higher, and the vent CSA is slightly larger. The chamber has to be stuffed a little in the section to the top and a bit less in the section just before the vent. Particle velocity at the vent seems really low (rule of thumb is nonlinearity starts around 18m/s, and Hornresp sim says that peak particle velocity at the vent is a lot lower than that), but that vent looks mighty small to get away without causing any chuffing noises.

[Millstonemike]

Hello,
I just built this box (one of my first ever builds) and am powering it with the same Lepai 2.1 amp using the power supply that came with the amp. Can I ask how much you are able to turn the sub volume up with your amp? I can barley turn sub volume up off the minimum setting (less than 25%) without the subwoofer sounding really bad. Also, the crossover does not seem to do much. I don't know if I got a bad subwoofer or if there is a problem with my amp. I'm leaning towards an issue with the amp since crossover seems to do very little.

Thanks,
Daryl

Which Lepai amp (PE part #)?

[ceiol]

That MLTL looks good. About 9 liters for the enclosure. Sounds reasonable.

Can’t wait to see your build and testing

[RexDog]

Which Lepai amp (PE part #)?

Lepai LP-168HA 2.1 2x40W Mini Amplifier + 1x68W Sub Output

Part # 310-308

[Millstonemike]

Lepai LP-168HA 2.1 2x40W Mini Amplifier + 1x68W Sub Output

Part # 310-308

IIRC there have been reports of issues with this amp including sub channel LP and general issues. Try the sub on one of the L-R channels to see if you have the same experience. Then perhaps the LP filter is not working.

[RexDog]

IIRC there have been reports of issues with this amp including sub channel LP and general issues. Try the sub on one of the L-R channels to see if you have the same experience. Then perhaps the LP filter is not working.

Good idea! I just tried this. I disconnected the speakers from both left/right channels and I hooked the sub up to the right channel. I was able to crank the volume up to max with no distortion/noise from sub but volume from subwoofer was very low/quiet. With my other speakers connected to these channels they are quite loud.

[Millstonemike]

Good idea! I just tried this. I disconnected the speakers from both left/right channels and I hooked the sub up to the right channel. I was able to crank the volume up to max with no distortion/noise from sub but volume from subwoofer was very low/quiet. With my other speakers connected to these channels they are quite loud.

The TB W5 in the Voxel has very low sensitivity. There would additional volume leveling issues if you L-R mains are also 4 ohm.

I presume you're going to return the Lepai to PE as DOA. I'd opt for the SA 70 plate amp (`$50) for the Voxel and a separate amp for the L-R mains. But, the SA 25 plate amp is on sale for $40 and PE currently has a restock SA 25 for $20. If you can retrofit the plate amp into the sub enclosure, I'd jump on it.

[RexDog]

The TB W5 in the Voxel has very low sensitivity. There would additional volume leveling issues if you L-R mains are also 4 ohm.

I presume you're going to return the Lepai to PE as DOA. I'd opt for the SA 70 plate amp (`$50) for the Voxel and a separate amp for the L-R mains. But, the SA 25 plate amp is on sale for $40 and PE currently has a restock SA 25 for $20. If you can retrofit the plate amp into the sub enclosure, I'd jump on it.

Thank you very much for all the advice, I might pick up those plate amps just to have something to play around with. My final goal is to work this subwoofer into a portable 2.1 setup that could be run off a 12v lead acid battery. I spend a lot of time vacationing out in the woods at a place with no electricity.

I ordered a Chinese 2.1 amp 2x50w and 100w sub channel currently on the slow boat from China. Hopefully that will work out ok.

[Millstonemike]

Pic of the amp please.

My boombox. It has to run up to 12 hours, at the edge of the Atlantic, with afternoon dance party duty. Those are two 12 V 18 ah lead acid batteries for size reference.