Announcement

Collapse
No announcement yet.

Budget Tower Design - To Make Use of 48 Drivers - Advice Needed

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

  • Budget Tower Design - To Make Use of 48 Drivers - Advice Needed

    Drivers I'd like to use up on this project: 16 - MCM PN# 58-4790 5.25" mid-woofs (8 ohm) and 32 - MCM PN# 58-4560 mylar dome tweeters (4 ohm). Goals: 1) Something punchy yet commanding (I have a sub I can use them with) , 2) as well balanced as possible (not sound like some Bose piece), 3) use up all 48 components. Driver specs: tweeters are 4 ohm and roughly 2 5/16" square. I thought for sure I could dig up the actual specs on these drivers before posting this, but no luck (drivers were purchased circa 2001 from MCM on closeout). So, I'm asking the worst kind of question; a very vague, generalized one; I have 2 main thoughts on woofer layout and crossover: 4 per cabinet series/parallel (= 8 ohms) used as boost woofers below say 200 Hz with a single large coil and maybe impedance comp, the other 4 series/parallel with a single coil say .33 mH (I have 2 of these .33 mH Solens collecting dust) with either a single column of 8 drivers with the boost woofers at the bottom, or 2 columns of 4 with the boost column of 4 against the "out" side of the cabinet (mirror-image). On the tweeters, that's where I really need advice on how to do something half way effective with them. Again, sort of thought about either a column of 16 per cabinet (ala Infinity Reference towers), or 4 columns of 4 inline in a splayed arrangement (say 15-20 degrees curvature from one column to the next X 4. But, as my last project shows, I don't have the tools/experience to know if these are feasible goals or design ideas. Something that can whack ya in the upper bass with smooth-ish mids and convincing high end would be considered a win. I have used these woofers before and with a large cabinet they play fairly "big". But I'd be looking at something more like .25 - .35 cubes per woofer max on this design (optimum is like .55 cubes per vented, which works but is not practical.)
    MCM 58-4790 mid-woofer back MCM 58-4650 Mylar dome tweeter MCM 58-4790 mid-woofer front

  • #2
    You are totally wasting your time without Thiele/Small parameters for the drivers,.
    Read (and reread) the sticky thread on this forum from HongRn titled "Easy T/S parameters from LIMP".
    The jig will cost you about $5.

    Meanwhile, start breaking in the drivers by connecting 4 of them in series/parallel and playing some rock/funk for a few hours.

    Once you have the T/S parameters you can then design the tower box using WinISD or Unibox.
    I'd suggest using 6 of the mi-woofers per box similar to the Stentorians / Uluwatu or the "Trump Towers".
    Use of the of tweeters per box, sell the others to 14 yo guys for their cars.

    Hope this helps.

    I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
    "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

    High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
    SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
    My Voxel min sub Yet-another-Voxel-build

    Tangband W6-sub

    Comment


    • #3
      Thank you for that, I deserve that.

      Comment


      • #4
        Originally posted by rickpepper View Post
        Thank you for that, I deserve that.
        ​You have enough drivers there for a couple of nice line arrays. Keep doing research and you'll get a better sense of what is possible. Hopefully your cabinet making skills are up to it.

        Comment


        • #5
          Originally posted by rickpepper View Post
          Thank you for that, I deserve that.

          No, no, no. That wasn't a "putdown", it was some advice to focus on the fundamentals, one step at a time.
          To do otherwise is to waste your time and money. You should be able to make a nice speaker with those mid-woofers.

          I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
          "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

          High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
          SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
          My Voxel min sub Yet-another-Voxel-build

          Tangband W6-sub

          Comment


          • #6
            Agree with Don - head over to the speaker gallery and check out the trump tower thread there - you could make a few sets like you see there. The mcm drivers are good value units and with help from the guys here you could get a few pairs of very very nice speakers.

            Comment


            • #7
              Originally posted by donradick View Post

              No, no, no. That wasn't a "putdown"
              Was that before or after you had your morning coffee?

              Comment


              • #8
                I have some of the same tweeters,
                which I trimmed on the table saw in order for them to fit closer together.
                Click image for larger version

Name:	DSCF0574 (Medium).jpg
Views:	1
Size:	203.8 KB
ID:	1345109

                Comment


                • #9
                  - I didn't take it as a put-down, you are fundamentally very correct. I'm on a Mac so it will take some networking (with people) to get ZMA files made. So it looks like you had a similar idea with those tweets, do you have the TS parameters on them? What was your application? I realize I sound like a typical noob, but I'm not (honestly), just that I don't have access to WinISD, and I totally failed on making sure I had the TS values on these drivers (I must have had them at one point), and after having them stashed in the basement for 15+ yrs, I just want to turn them into something retro-looking, pseudo-massive and functionally better than a Bose ;~).

                  Comment


                  • #10
                    Originally posted by rickpepper View Post
                    - I didn't take it as a put-down, you are fundamentally very correct. I'm on a Mac so it will take some networking (with people) to get ZMA files made. So it looks like you had a similar idea with those tweets, do you have the TS parameters on them? What was your application? I realize I sound like a typical noob, but I'm not (honestly), just that I don't have access to WinISD, and I totally failed on making sure I had the TS values on these drivers (I must have had them at one point), and after having them stashed in the basement for 15+ yrs, I just want to turn them into something retro-looking, pseudo-massive and functionally better than a Bose ;~).
                    ​Hello.
                    No, I have no data on those tweeters other than what I can measure with an ohmmeter. However, those tweeters are not so complicated as to be difficult to use, their small size makes them ideal for a line array. I could probably surmise a whole lot about them just by listening to them via frequency sweeps and fixed test tones. You really do need the T/S parameters for the woofers if you want to utilize them optimally.
                    ​Yeah, I'm also in the same boat when using my MacBook, but I now also have a Windows 10 laptop.

                    Comment


                    • #11
                      Rickpepper- if you are willing to post your general location you may be near another forum member with a full measurement setup. I have seen some on here before offer their services. Then you could have a response file for each driver too. You could also put out an offer to ship one of each to somebody for measuring, I've seen that happen before too. Unfortunately I'm offering other people's services for them but I've seen it done willingly more than once.
                      Projects:

                      transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                      Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                      References: http://techtalk.parts-express.com/sh...-My-References
                      Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                      Comment


                      • #12
                        I'm in the southern half of Minnesota. I had a working "WineBottler" build of WinISD running under OS X 10.6.8 but since had to upgrade and it relied on Rosetta. Tried doing a new build but couldn't make it work, and I can't seem to get WinISD Online to work on a Mac anymore (most likely a Java issue.).

                        Comment


                        • #13
                          I've got a similarly-vintaged pair of Vifa D27AG's collecting dust (figuratively) as well, maybe is interested in 32 more of the MCM Mylar domes, cheap, to be done with it ;~)

                          Comment


                          • #14
                            Usually a sealed speaker can use a rather large range of box volumes, so I disagree about needing the ts parameters. I'd estimate a size that is not visually too big for your room, or desires. Better to be too large than too small I think. You can always add filler material to make the volume effectively smaller if needed. The x-over will be a WAG, but likely a lot of fun trying different caps, and coils. Beer may be needed during the process. Get a filter design from AE for one tweeter. Wire yours up for a 4 ohm load, like one tweeter would be, and use the AE tweeter filter. Get him to give you some help with padding too. I've built speakers with no clue about anything, and loved them. That was a long time ago, but I fondly remember a couple of those speakers.

                            Comment


                            • #15
                              rpb, that's not far from what I was just about willing to do, but I was hoping to get some reality checks on how I could array at least a goodly portion of those tweets in an effective manner (maybe get some interesting imaging but no stupid phase artifacts). As I like to say, "there's an art to cheese", referring to cheesy designs, cheesy applications of technology, any scenario where the components (of whatever manner they may be) are "lo-fi". Applied to this it means, I'd hate to "waste" those Vifa D27's (even though they've been doing NOTHING for 13 years or more ;) to go with the 5's, because those 48 drivers were dirt CHEAP, and I'd enjoy getting something "usable" out of them. Plus they'll be a nice conversation piece at my 35th reunion; something retro, something punchy (can always deploy a sub), and "fast". The pair of (much smaller) towers I built with them can be seen in this pic, and I do recall running the parameters and determining they performed better in a larger vented box (most cheap drivers seem to follow that pattern.)

                              Comment

                              Working...
                              X