Announcement

Collapse
No announcement yet.

Small BT boombox build - help please

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by STIchris722 View Post

    Well you definitely have me beat on your last build! I have always wanted to try the succession of cuts so that the wood can be folded as you did! I really like what you did with that. Hopefully you don't think I was bashing you earlier; I was simply trying to give you some ideas to re-route your current build a little bit. From what I can tell, you know what you are doing, but are rather looking for some input from the community. There is no harm in that by any means. If you don't mind me asking, how did that little guy turn out SQ-wise?

    I spent some time last evening researching some ideas/parts for your current build, but was striking out with the new Dayton DSP BT boards. They make a 2x50 @4ohms and a 1x100 @4ohms that I believe can link together, but don't play well with a battery board (I believe). There was also something about the boards losing their BT function? I couldn't find all the information on it and @4am my brain stopped working! keep us posted on what you come up with.

    Cheers,
    Chris
    Dayton has new battery boards in 3S and 5S versions (3 cells and 5 cells). The newer battery management modules do not depend on the Dayton 2x30/50 series amps for any functionality (as did the earlier 3S boards - battery charge current limit, IIRC). The new boards can be used with any amp and charger (wall wart). So, if you want a 2.1 amp your good with the new battery boards. And the 5S battery module will give you 21 V on portable power. That's over 3 times the W rms into the drivers compared to the 3S battery modules.

    A larger NPE cap (non-polarized electrolytic capacitor) in series with a driver will give you a 1st HP in the lower frequencies. Larger NPE's are pretty cheap compared to the film and metal XO caps. .For example, a 200 uf NPE in series with a 4 ohm driver will give you a HP Fc at ~200 Hz.

    Comment


    • #17
      Originally posted by STIchris722 View Post

      Well you definitely have me beat on your last build! I have always wanted to try the succession of cuts so that the wood can be folded as you did! I really like what you did with that. Hopefully you don't think I was bashing you earlier; I was simply trying to give you some ideas to re-route your current build a little bit. From what I can tell, you know what you are doing, but are rather looking for some input from the community. There is no harm in that by any means. If you don't mind me asking, how did that little guy turn out SQ-wise?

      I spent some time last evening researching some ideas/parts for your current build, but was striking out with the new Dayton DSP BT boards. They make a 2x50 @4ohms and a 1x100 @4ohms that I believe can link together, but don't play well with a battery board (I believe). There was also something about the boards losing their BT function? I couldn't find all the information on it and @4am my brain stopped working! keep us posted on what you come up with.

      Cheers,
      Chris
      I would say know what I'm doing loosely I've had some good help along the way from members of this forum to take my builds to.the next level. I don't take any responses on here as bashing as I'm a beginner. With those peerless I saw "half space" and massive magnets and probably got caught up thinking small box over functionality.

      sound wise the unit turned out well, doesn't distort and can handle the bass extremely well. I've use those drivers on most projects and they have a love hate relationship with most people, but with me I think they do a great job. If I could make that unit again I would have enclosures of 0.17-0.18cuft as I know it models a FS of 58hz and sound a bit better again I made some PC/Bookshelf speakers doing that and you can notice the difference

      edit...and also not have the ports on the front facing, i think it works\sounds better with ports at the rear.
      Last edited by 3rutu5; 01-22-2020, 06:00 AM.

      Comment


      • #18
        Any thoughts on whether the 3.5" peerless could act as a stand alone full range?

        Comment


        • #19
          To ME, 264-1064 (4ohms, glass cone) looks a bit better than 264-1062 (8ohms, paper cone).
          A bit flatter. A bit higher sensitivity. Probably able to play a bit lower. Still, they BOTH only have about 2-1/2mm Xmax.

          Comment


          • #20
            Originally posted by Chris Roemer View Post
            To ME, 264-1064 (4ohms, glass cone) looks a bit better than 264-1062 (8ohms, paper cone).
            A bit flatter. A bit higher sensitivity. Probably able to play a bit lower. Still, they BOTH only have about 2-1/2mm Xmax.
            True, I'm guessing these 264-1600 don't go higher enough on their own to be able to function without a tweeter

            Comment


            • #21
              Don't "guess" !
              Look at the PDF of the plots. Looks like it's pretty much done by 4kHz.

              Comment


              • #22
                Originally posted by Chris Roemer View Post
                Don't "guess" !
                Look at the PDF of the plots. Looks like it's pretty much done by 4kHz.
                I've abandoned that train of thought, going to use those ND65-4 for good and not evil. 0.045cuft (each) tuned to 70hz and port apparently 150mm, but would like you input on the port if possible, already had the BSC sorted.

                Comment


                • #23
                  I can't tell w/out knowing your port ID. If 20mm, then it'll tune your box to 70Hz.
                  In the last few yrs the specs for that driver changed here on site. Only the Vas changed, but it went up from 0.02cf to 0.03cf (a 50% increase).
                  Your box SEEMs small (at a Vas of 0.03). If your size is fixed, I'd tune it a bit higher. If your port is 20mm, I'd go 125mm for length (Fb in the mid 70s).

                  Comment


                  • #24
                    Originally posted by Chris Roemer View Post
                    I can't tell w/out knowing your port ID. If 20mm, then it'll tune your box to 70Hz.
                    In the last few yrs the specs for that driver changed here on site. Only the Vas changed, but it went up from 0.02cf to 0.03cf (a 50% increase).
                    Your box SEEMs small (at a Vas of 0.03). If your size is fixed, I'd tune it a bit higher. If your port is 20mm, I'd go 125mm for length (Fb in the mid 70s).
                    Yes it is 20mm, I originally modelled 0.03, but when you put the BSC, amp, batteries and BT board you really don't have much of each enclosure to fit either a port or have any room internal. So it is rebuilt using the rest of the scrap pine I had which happens to be internally 0.095 overall, or the 0.045 I assumed (once I put the dividing wall in. 70hz seems to model ok, I think it gave mid 60's at F3. I just need to find an elbow joint for the electrical conduit so there is a bit of space to the opening of the port

                    Comment


                    • #25
                      I'll admit it does get a bit confusing sometimes. The relationship between VAS and VB seems to be one open to interpretation. The ND91's not have a VAS of 0.05cuft, yet works really well in the passive aggressives in a 0.04 flat pack box.

                      Comment


                      • #26
                        Box size requirements are driven by Vas and Qts.
                        Given 2 drivers of equal Vas (let's just say 0.50cf), one with a higher Qts will need a larger box.
                        With a Qts of 0.40, driver "A" generally likes a (vented) box around 0.50cf (close to Vas), while driver "B" (with a Qts of 0.50) wants more like 0.80cf.

                        Comment

                        Working...
                        X