Announcement

Collapse
No announcement yet.

The Bantams Micro Speaker System

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

  • #76
    The AMT Tweeter body is round...you can cut the hole for the tweeter any size you want, it all depends on the method you use. I used a Fostner bit that was close to the tweeter barrel size as the set I own didn't have one that was exactly the same size. On the first set I built, I used foam sealant to mount the tweeters. That proved to be difficult to mount, so for the next few sets, I made the hole slightly smaller and used a few wraps of electrical tape to make the fit tight. Ultimately, sealing the tweeter to the baffle with silicone really does a fine job of securing it, as well as sealing it, at least on the 6 Bantam-themed projects I've done so far.

    If you can make the tweeter opening basically the same size as the tweeter barrel, than that's less work you have to do. I just didn't have an exact match for it, so that's why I used the 'build up' method with foam and tape. On occasions where I've made an opening smaller and tried to sand a perfect circle uniformly to get a slightly larger opening, it usually seems to be difficult to pull this off and you end up going from "It doesn't fit yet" to "heck, well now it's a little loose" in one sanding step. Often a "Press-Fit" tweeter will be spec'd to mount in a 'standard' size opening and be designed with a slightly tapered barrel so it "snugs up" slightly as you press it in the cabinet. These, being stand-alone automotive tweeters are not built that way.

    Regarding sealing things up... yup, Wolf's got it, I was speaking of where the wire exits the plastic housing.

    Here's a pic of what I'm talking about...

    Click image for larger version

Name:	Bantam Tweeter Wire Seal.jpg
Views:	404
Size:	299.0 KB
ID:	1438769
    The tweeter being designed as an automotive type driver doesn't need to be sealed up if used in an automotive environment... it was never intended to be used in a speaker cabinet, just 'taped' to an A-pillar in a car. The pressures inside a speaker cabinet will likely act on the tweeter, causing unwanted vibrations of it's diaphragm of some type... that's why I sealed up where the wire leaves the plastic tweeter body.

    TomZ
    *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 *Cello's Speaker Project Page

    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

    Comment


    • #77
      I like to template any hole I need to make. If I make a hole that is slightly oversize, I will put heatshrink on a flush-trim bit's bearing so that the copy is slightly smaller. Varying the number of layers of heatshrink can really zero in on the right hole diameter. I use scraps of 1/2" for this and then label the scrap piece to what the hole is for.

      I did this recently to make rear mounts for 1.25" PVC vents and it worked very well.

      Comment


      • #78
        Dukk,
        That is a nice trick. I went lazy, there was no way I was breaking out the circle jig when I had a fostner bit that was 'close enough'
        TomZ
        *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 *Cello's Speaker Project Page

        *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

        Comment


        • #79
          Hi TomZ,

          First of all: Thanks for your development and the time and efforts you put in documenting it!

          Since I'm located in Germany it seemed unreasonable to get the necessary parts directly from Parts Express due to pretty high shipping costs. Thus, I ordered from a company located in the Netherlands (Soundimports). Luckily, I found all parts as listed - except for one: Instead of the air coil from ERSE I got one from Mundorf, which has a 0.01 higher DCR, see here. Does that matter? (Sorry, if this a complete noob question ...)

          Unfortunately, I have to wait until the middle of August before the parts are delivered. But as they say: Anticipation is the greatest joy ...

          I'm super excited to see, I mean hear how the Bantams will perform against the Microspeaker µ from Quint, which I built not too long ago - both speakers have pretty much the same size ...

          Audio Novize

          Comment


          • #80
            That difference in DCR is negligible.
            Wolf
            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

            *InDIYana event website*

            Photobucket pages:
            http://photobucket.com/Wolf-Speakers_and_more

            My blog/writeups/thoughts here at PE:
            http://techtalk.parts-express.com/blog.php?u=4102

            Comment


            • #81
              Great, thanks for the quick answer!

              Comment


              • #82
                Just a quick update: I finished building the Bantams & I am super happy: They are amazing!

                But what did I do wrong: Are the Bantams supposed to play as of 40 Hz? Seriously, there almost seems to be a glitch in the matrix: How can (passive) speakers of that size produce such a low bass at full volume?

                If someone is interested, I documented (and am still documenting) the build in a German forum - of course, it's in German, but I also included a fair amount of pictures: http://www.hifi-forum.de/viewthread-205-1138.html

                TomZ: Thank you again, what a great little speaker you have developed!

                Comment


                • djg
                  djg commented
                  Editing a comment
                  Well, the pictures aren't in German. Nice writeup (I assume) and pics.

              • #83
                For certain aspects regarding the build of the Bantams, I chose a slightly different approach. Maybe some of them are are helpful for others:

                The cutouts for the chassis I did with the help of a circle hole cutter (that attaches to a regular drilling machine):
                Circle Hole Cutter

                To prevent the screws from getting lose over time in MDF (or if installing the chassis multiple time) I glued little MPX pieces on the back of the front baffle:
                MPX pieces for screws

                For the sealment of the tweeter I didn't use glue or silicone, but instead a kneading mass (which allows easy removement of the chassis if necessary; it also allows for installing the tweeter after completely building/glueing the speaker case):
                Sealment Tweeter

                Instead of using a terminal - and since space is limited - I used press-in sockets:
                Press-in Sockets

                With respect to damping I chose 4mm of felt for the sides as well as the for the top and bottom of the speaker case. Also, I added one "sheet" of damping between the chassis and the cross over:
                Damping

                Comment


                • #84
                  Great job, they came out nice, the stone look is great for a small speaker like this. I'm glad you like them.

                  The flexible putty you used for the tweeter is a nice way to seal it up as well. These tiny speakers sure are interesting to get put together.

                  Just curious, did you see this design in the AudioXpress magazine or just online somewhere?

                  TomZ
                  *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 *Cello's Speaker Project Page

                  *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                  Comment


                  • #85
                    Thank you!

                    Regarding your question: I was actively looking online for small-sized speakers for my desk - and "somehow" I found the Bantams. And I am very happy I did!

                    Comment

                    Working...
                    X