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Voxel - a mini-sub+

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  • Is that built into a cooler? That is sweet!
    I have a 35 amp hour lead acid battery I used to power a couple of speakers and a tang band 3" sub with a Sure 2x25w and a Sure 50w mono amp. That battery would last me all weekend but I have pretty much wore out the rest of the system so time to upgrade!

    This is the amp I ordered, I hope it works out. I have ordered some Chinese amps that turned out to be pretty bad. Still hoping to find a gem. I did find a Chinese preamp 2.1 board that works pretty well for about $8.00. I was using it on my old setup and was pretty happy with it so I am hopeful one of these cheapo 2.1 amps will work out!


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    • What is that Sure board you are using?

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      • Originally posted by RexDog View Post
        Is that built into a cooler? That is sweet!
        I have a 35 amp hour lead acid battery I used to power a couple of speakers and a tang band 3" sub with a Sure 2x25w and a Sure 50w mono amp. That battery would last me all weekend but I have pretty much wore out the rest of the system so time to upgrade!

        This is the amp I ordered, I hope it works out. I have ordered some Chinese amps that turned out to be pretty bad. Still hoping to find a gem. I did find a Chinese preamp 2.1 board that works pretty well for about $8.00. I was using it on my old setup and was pretty happy with it so I am hopeful one of these cheapo 2.1 amps will work out!

        My amp is not a Sure amp. The Sure unit you see is a pre-amp (discussed below).

        I have not used or tested your new amp. But if IIRC it had a positive review on my other forum. It is based on TI's TPA3116 chip - that's good.

        First Issue: You're battery has plenty of capacity. But it's only 12 V. And that's an issue. I have the same capacity in two 12 V 18 aH batteries. But I'm running them in series for 24 V.

        The total W rms an amp can deliver is determined by two factors: the PS voltage and the speaker impedance. The TB W5 is 4 ohms and that's good for power. But it's fairly insensitive. At 12 V, you'll only get some 16 W rms from the amp. And not a lot volume from the W5 - especially outdoors. Step up to 24 V and your looking at close to 70 W rms into a 4 ohm driver. Plenty for the W5. So my first suggestion is you'll need a step-up converter to from 12 V to 24 V.

        Potential Issue: You may need a pre-amp if your source is a smart phone or mp3 player. Your amp has an extra op amp that may provide enough signal gain for them. If not, these TPA3116 based amps are set to 26 dB gain. Headphone output does provide a high enough signal level to drive the amp to full power. It's like having a Dodge Hellcat but never getting out of 1st gear. If you look closely at my control panel, you'll see a Sure headphone pre-amp used to solve that issue. It provides an additional 15 dB signal gain. And it'll run directly off a 12 V to 24 V battery - nice and easy integration for ~$10.

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        • Interesting points. I do have some Chinese preamp and tone control boards to play (worked out well with my last setup) with but I will also definitely add a second battery. I did not think of that one.

          If you ever need a 2.1 low pass filter, I have had good luck with this NE5532

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          • Originally posted by RexDog View Post
            Interesting points. I do have some Chinese preamp and tone control boards to play (worked out well with my last setup) with but I will also definitely add a second battery. I did not think of that one.

            If you ever need a 2.1 low pass filter, I have had good luck with this NE5532

            I just tested and reviewed that 2.1 pre-amp. you'll see it in the list of current posts "Sanwu Sub-woofer Pre-amp Module - Test Results" If you need additional gain, that pre-amp unit can provide it. Just use the L-R in and out in front of your main amp (i.e., ignore sub out and it's pots). YOu'll get up to 4X signal gain using the master volume pot.

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            • Originally posted by RexDog View Post


              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.
              RexDog, when did you order the Lepai 2.1? We're trying to get an idea whether there is a "new, improved" version.

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              • Sorry, just saw this.
                Order Placed On:
                12/05/2017 08:08 AM


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                • So I picked up one of these little 2.1 amps while I am waiting for my Chinese amp to show up 2.1 Hi-Fi Class D Audio Amplifier Board 2 x 15W + 30W 10-18 VDC
                  https://www.parts-express.com/21-hi-...8-vdc--320-608


                  Major difference, I can crank this little guy all the way up and it sounds great. That Lepai 2.1 was definitely bad right out of the box.

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                  • I recently built a Voxel. It turns out the Dayton SA25 amp will just barely fit in the original dimensions, if you're going to hide it in the corner and are not concerned about having a specific front and back. The driver has to be set low and towards one end, the amp has to be set low and towards the other end, and the port has to sneak in above those two.

                    Don't pay too much attention to my paint job - I'm not good with paint in the first place, and figuring out how to work around the installed port tube made it even worse. Next time I use a double-flared tube, I'll either try to assemble it through the driver hole after the box is finished, or I'll recess the flare so I can sand right past it.

                    Ultimately, thanks to Paul for yet another well-documented design. I know there's a lot less that goes into sub design than speaker design, but this is still a good pairing. I also know a lot of people have built this with a more powerful amplifier, but I think the SA25 pairs really nicely. The port velocity on 25 watts already models to 26 m/s, and I had to spend some time with a round sanding stick cleaning up the joint where the two port tubes are glued together to prevent chuffing. The driver is a beast, though; with a bigger port (and a bigger box to hold said port) I suspect the 40w driver rating is pretty conservative.

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                    • Originally posted by aramid View Post
                      I recently built a Voxel. It turns out the Dayton SA25 amp will just barely fit in the original dimensions, if you're going to hide it in the corner and are not concerned about having a specific front and back. The driver has to be set low and towards one end, the amp has to be set low and towards the other end, and the port has to sneak in above those two. Don't pay too much attention to my paint job - I'm not good with paint in the first place, and figuring out how to work around the installed port tube made it even worse. Next time I use a double-flared tube, I'll either try to assemble it through the driver hole after the box is finished, or I'll recess the flare so I can sand right past it. Ultimately, thanks to Paul for yet another well-documented design. I know there's a lot less that goes into sub design than speaker design, but this is still a good pairing. I also know a lot of people have built this with a more powerful amplifier, but I think the SA25 pairs really nicely. The port velocity on 25 watts already models to 26 m/s, and I had to spend some time with a round sanding stick cleaning up the joint where the two port tubes are glued together to prevent chuffing. The driver is a beast, though; with a bigger port (and a bigger box to hold said port) I suspect the 40w driver rating is pretty conservative.
                      Excellent work getting it all to fit in there. Glad to hear the SA25 can pair with it.
                      Isn't it about time we started answering rhetorical questions?

                      Paul Carmody's DIY Audio Projects
                      Twitter: @undefinition1

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                      • Built one using The Dayton 25W amp and the 1 1/2" vent about 4 years ago. Just saw the page now dedicated to this setup. I picked parts unknowingly that matched the Voxel. My son was infatuated with bouncing woofers and I did not want my 8" pissing of the neighbors so we built him a little W5 setup. My enclosure was a little over spec.*

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                        • Not very loud but loud enough for normal listening. Very DEEP though. My 8" Energy was dead at 35 HZ but this little W5 was still going at 30HZ.

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                          • Moved to a house a couple years ago. So I upgraded the amp and got a larger port this month. With the amp and bigger port taking up room in the enclosure I am a little bit closer to the .32 recommended size. Because my box is long I was able to lengthen the port some and still get the bass down deep while gaining ALOT of volume and eliminating the port chuffing. This thing is pretty bad-*** now. I just hope he does not blow it up running 70 watts of Godzilla bass through it constantly. And they are not lying in the reviews when they say the 70w Parts Express amp runs hot!

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                            • cool build snortzie!
                              what's the new volume and port size? looks like a 2" diameter flared port. -- how long of a port were you able to stuff into the box (elbow?)
                              *

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                              • Originally posted by snortzie View Post
                                I picked parts unknowingly that matched the Voxel.
                                The old saying "Great minds think alike."*

                                The end user seems happy enough with that smile.

                                I bet the amp fails before the Tang Band.

                                Nice build (and upgrade).

                                *

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