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Aurasound NS3 portable spkr bx progress photos.

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  • Aurasound NS3 portable spkr bx progress photos.

    I picked up 4 Aura NS3-193-8A 3" Extended Range Drivers when they were on sale about 6 months ago for the purpose of building a portable BT spkr box. I heard some good reviews and feedback from other members about the quality of sound that these little drivers can produce. One member even said he was going to do a build with them and post it to the YouTubes and since this is my first proper 2-way build with XO i was eager to hear and see what he had to say. unfortunately i don't think he ever did it. So after some research and chats with tech support and other members i came up with a parts list for the electronics and a schematic for a 2nd order 4k crossover. I decided to use a 3PDT rotary switch to change inputs from BT to AUX. A 12v USB charger and battery status LED were also added to the scope of work. Once that was finalized i set out to design and build the box. I started with a basic sketch of the box based on the aprox size required by the drivers. I used paper cutouts of the components and a cardboard mock-up of the box to get the best looking size and layout in my opinion. Box construction is .5" MDF. The baffle is also MDF but laminated with 2mm thick 'diamond plate' PVC material and the control panels and speaker rings are machined out of .25" aluminium plate. Blind holes drilled and tapped from the backside of the aluminum secure them to the baffle. Im still undecided as to the finish of the box itself. I was thinking of spraying with black Plastidip, or, covering the entire outside of the box with laptop graffiti stickers. Still undecided but open to any and all suggestions from you guys. I posted a few pics of the work so far and will post more pics and specs as i progress. I would like to get everyone's thoughts on this project. Thxs.

  • #2
    Few more pics.

    Last edited by TITMAS; 09-13-2019, 07:43 PM.


    • #3
      Wow that looks good so far can’t wait to see the actual box


      • #4
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ID:	1421937 This past week i was able to cut and assemble the box. I used .5" mdf for the box and a .75" bullnose for the edges. this way i can have a small lip for the front baffle to sit against. I decided to try using some Tolex for the outside of the box. I think it was a good combination of textures and colors with the yellow diamond plate baffle.


        • #5
          Before i assembled the box i laid out where the x/o's and amp would be mounted inside the box and drilled in some brass threaded inserts to mount the boards. The back panel will have all the other boards and batteries mounted to it with the same threaded insert nuts. I think it makes for a cleaner assembly and the option of easily removing them if needed. i also threaded in some 1" nipples into the backside of the speaker rings and than mounted drivers to the ring.This way its a lot easier and more accurate to mount the whole assembly as one unit instead of trying to align both drivers and trim ring with one hand and bolt it in place with the other hand. I can than insert them into the baffle with nuts on the inside to hold everything in place.

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          • #6
            Very interesting project!! Love the baffles!


            • #7
              The past two weeks i was able to get a lot done on the box. I fully assembled the baffle and mounted all the PCB's inside, as well as started hooking up all the wires. I decided to mount the battery boards through the back panel so that if i ever needed to remove or access the individual cells i could just detach a small panel covering the battery and not have to remove the entire back panel. Because of multiple wires that need to be connected into the battery boards i decided to make two distribution strips, one (-) and one (+) to accommodate all the connections instead of using those horrible spring clip jacks that come with the board.The strips are just a small chunk of aluminium bar that i drilled and tapped and use fork connectors for the hookup. I'm still figuring out how and what to make the battery access panel out of but most likely it will be either thin aluminium or some type of black plastic. The small connection panel on the back right was necessary because most of those chassis mount components will only handle about a .25" of material. plus it keeps everything discrete and protected.

              I originally planed to have a wall dividing the box into right and left compartments but with all this wiring it might not be possible. Does anybody have any input as whether or not this will cause any issues with the ports? as it stands now you can see right through the box, in one port and out the other. Without the wall in between even my limited aural knowledge tells me that its probably not a good idea. Would putting a 90 degree bend in each port eliminate any immediate concern of one port starving the other for air flow? Just a thought.

              All the components ( BT, amp, boost board ,battery boards,) seem to be working fine with one another with the exception of the volume control board. It seems no matter how i hook it up, RCA or TRS connectors, all i get out of it regardless of the pot position is just some low level white noise. When i bypass it and go directly from the BT into the amp i get audio output, albeit with a very faint hum that can only be heard when no music is playing so I may use a 12v isolated DC converter at the BT's DC input to eliminate it. Aside from that the only component yet to be installed is a speaker protection/boot delay relay that will hopefully eliminate this substantial thud/crack/pop that happens upon power up. There are however still a few more things left to do though.

              1. wire management
              2. boot delay/speaker protection PCB to be installed
              3. paint back panel/add more screws/battery cover
              4.install BT antenna
              5. resolve volume control issue
              6. im sure ill think of something else right after i post this.

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              • #8
                I don't think you will have any issues with the ports the way they are now. However, with no center divider you could get crosstalk between the two channels. They can fight against each other when producing stereo sound. That being said, I have built a Sprite boom box with no center divider and never felt the need to add one.


                • #9
                  That really came out nice looking. How much cooler is that than ANYthing you could ever buy from ANYwhere!
                  How does she sound?
                  Any issues with noise with all those electronic doo-dads in there?
                  I like the set screw method of port length adjustment you used. Want a different tuning? No problem!

                  Again, really cool looking!
                  Zarbo Audio Projects Youtube Channel: * 320-641 Amp Review Youtube: *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                  *Part 2 *Gluing multiple curved laminations of HDF


                  • #10
                    Originally posted by tomzarbo View Post
                    How does she sound?
                    Any issues with noise with all those electronic doo-dads in there?
                    I like the set screw method of port length adjustment you used. Want a different tuning? No problem!

                    Again, really cool looking!

                    Thxs Tom. as far as sound goes it's loud and boomy. I don't have any equipment to test the output but to my relatively untrained ear it sounds great. Plenty of clarity and deep bass even at high volume with little distortion. There is a bit of white noise or hum with all the electronics in there. I'm in the process of installing some DC to DC isolated converters for the power supply on both the Bluetooth and volume control boards and hopefully that will clear it up. I'm also going to put a speaker protection relay in to prevent the loud pop when powered up. The set screws on the tubes also allow me to remove them to access the boards that are mounted right above them.


                    • #11
                      So after taking a few weeks off to focus on some other things I was able to get quite a lot done on the boombox this past week. I ordered a small relay protection board from China and installed it between the amp and the crossovers. Unfortunately it produced such horrible white noise in a clicking sound that I haven't been able to resolve so I decided not to use it. So there's still a loud click and pop when first powered up.
                      I also soldered on a 12 inch piece of wire to extend the Bluetooth antenna from the board to the back panel. I haven't tested the range for the new antenna but it is possible to walk out to my mailbox and still have it playing while inside the house.
                      after adding two 12-volt volt dc-to-dc isolated converters to the power supply for the Bluetooth board and the volume control board it totally eliminated any ground Loop hum in the system.
                      apparently the volume control board was defective in some way because when I called tech support at Parts Express they offered to send me a new one and and when I hooked up the new board everything worked fine.
                      trying to make some sense of all of those scattered wires was a bit of a challenge and I'm not sure if the way I decided to wire it up was the best but I eventually cleaned it up enough to be happy with it. Each individual board has its own positive and negative power leads that come off of a distribution block. I'm not sure if I should have just daisy-chained one power lead from board-to-board.
                      once everything was wired up and working I had to take everything off of the back panel so I could paint it with a couple of coats of primer, two coats of flat black and two coats of flat clear. The edges of the MDF soak up quite a lot of primer so I used automotive filler primer and put on about five or six real light coats in succession to get the edges super smooth.
                      there are a few minor issues that I have with it, particular the Bluetooth board has a red status LED. To me it would make more sense to have a blue one but since the resistor on the board is size for a red LED that's what I'm stuck with.
                      there's still a few minor things left to do on it , for one, I need to make some kind of a cover for the batteries on the back cover. And I'd like to try to figure out how to use the speaker boot relay bored. If I can't get the board to work I may just go manual and install a two-pole switch on the speaker lines that I can turn on after the amp is powered up.


                      • #12


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