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  • Beginner needing a bit of assistance .....

    I actually have no clue to electronics , other than you grab the wrong part you will know it immediately . I'm a "Dyed in the Wool" mechanic , and builder when I'm bored .
    I guess I must be bored silly to attempt this at my age . As for boxes , I've built separate enclosures for the Bass , Mid , and High Drivers . Getting the cabinet volume took me a couple of days just trying to figure that out .
    The cabinets are 3/4" MDF

    I have these drivers / cross overs :

    1] I have four Infinity SM-150 Cross-Overs that are 500 hz. / 5,000 Hz.

    2] 2 ea. Eminence American Standard Series Beta-12A-2 43Hz. / 3800 Hz. 98db . I used their recommendations for the cabinet size . Unvented : .9 - 1.25 ; Vented : 1.25-4.0 cu.ft . My Bass cabinets are right at 1.3 - 1.35 cu. ft. after damping/bracing material is added .
    P/N 290-408


    3] 4 ea. Pyle Pro PDMR5 Mids w/ sealed backs . 450 - 7 kHz / 92 db. Intended to use 2 per enclosure .
    P/N 292-200

    4] 4 ea. Infinity Emit-R Tweeters , using 1 each per side (but ,,, they are 4 ohm) so ,,,,,, I've read you can use 2 and wire them in series for 8 ohm , but I don't know if I should even consider that option .

    5] I have 2 ea. Pyle-Pro PDS182 Mid-High Compression Drivers : 1500Hz - 20KHz . 103 db.
    ​P/N292-2618

    6] Not yet purchased : Selenium Exponential Horns HC23-25 if I go the Horn route .
    P/N 264-318

    Everything is 8 ohm. except the Emit-R's

    I know these aren't Ideal drivers , but with my wallet I hope they will work .
    With the Compression drivers at 103 db. and everything else at around 90+db. could I use an L-pad to dial back the horns ? Should I use Horns for the Mid-Highs or the Pyle-Pro PDMR5 ' s .
    Should I consider using a 2-way or a 3-way system ? X-overs ,, again , I don't know . I've read the more resistors etc. in a circuit can build heat and distortion .

    I have got the Bass / Mids . Time Aligned , but the horns are a vexing situation as how to get those to where they won't drown everything else that's happening . I know my project is not a high dollar project . These will be replacing some "lazy" particle board speakers , remnants of a full set of Infinity SM-150's drivers without cabinets I picked up in K.C. Kansas about 10 years ago . Should I go to a Dome Tweeter , should I stick with my horn idea ? I have never been able to understand electronics , I was supposed to become a Navigation Systems Technician on A-10 Warthogs when I enlisted in the A/F in 81' . I couldn't comprehend it , I had been a machinist/mechanic for years , and it was all old Greek to me .

    Steve

  • #2
    You have a lot of parts and you can piece them together to make a "speaker". But using the infinity crossovers with these Eminence and Pyle drivers will not be ideal.

    If you really want to go this route, designing a properly tuned enclosure for the woofers would be a good start, then go ahead and use your other drivers and the pre-made infinity crossovers with lpads on the tweeters. You can then dial them in to the level you want.

    You'll make music from these speakers, and they would be ok for a party, but they're not going to be up to reproducing music for critical listening. And don't measure them, lest you be shocked by freq response that is all over the place

    Comment


    • #3
      CEIOL is correct.

      For most beginners, a two way (Tweeter / MidWoofer) is plenty of challenge.
      It's not that you could make it perform well by working harder (like trying to run 10 miles versus 1/2 mile).
      The challenge to making all those drivers perform well will require years of experience.

      I would suggest getting a decent measurement microphone and using ARTA to measure frequency response.
      You could use this nice PE mike:

      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


      • #4
        The eminence Beta-12A-2 drivers are really a mid range type of driver. Sealed they can run down to about 80 hz and cover up to about 1,500 hz. Then you'll need a tweeter down to 1,500 hz. The Pyle-Pro PDS182 in a 12 inch SEOS horn could probably do this, but there's not much info on the Pyle tweeters or Pyle mid range drivers for that matter. It's not likely the Infinity tweeters can go to 1,500 hz, but again I did not see any published info.

        So out of what you have you could create a pro style high top 2-way. A custom crossover would be required. If you do the SEOS horn with the Pyle let me know I might be able to measure this. You might be able to sell everything else to fund the SEOS and save for a subwoofer.
        John H

        Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

        Comment


        • #5
          Originally posted by jhollander View Post
          The eminence Beta-12A-2 drivers are really a mid range type of driver. Sealed they can run down to about 80 hz and cover up to about 1,500 hz. Then you'll need a tweeter down to 1,500 hz. The Pyle-Pro PDS182 in a 12 inch SEOS horn could probably do this, but there's not much info on the Pyle tweeters or Pyle mid range drivers for that matter. It's not likely the Infinity tweeters can go to 1,500 hz, but again I did not see any published info.

          So out of what you have you could create a pro style high top 2-way. A custom crossover would be required. If you do the SEOS horn with the Pyle let me know I might be able to measure this. You might be able to sell everything else to fund the SEOS and save for a subwoofer.
          Thanks for your help ! It's appreciated . It looks like I'll do the horn arrangement instead of dome tweeters . I used Eminence's recommendations for a vented box . Their recommendations called for 1.25-4.0 cu.ft. my cabinets after damping will come out to 1.3-1.4 cu.ft . It was recommended I read Speaker Building 201 , is that a good read for someone with no experience ?

          If there is any interest I'll post a few pics one I resize them . My DSLR only goes down to 5 megapixel , so it's a download/edit/upload P.I.T.A. !

          Thanks to you all for your help ,
          Steve

          Comment


          • #6
            IMO start with the speaker building bible sticky at the top of the forum page, some of the links are broken but this should give you an idea if you want to keep going and spend the money for a book.

            Box modeling programs look at the internal volume and do not subtract for dampening. Your 1.4 cu ft box gives a peaking bass response when vented 3 dB peak at 100 hz when tuned to 60 hz. Sealed gives a smoother roll off and F3 of 84 hz.
            John H

            Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

            Comment


            • #7
              If you go to www.linearteam.org and download the FREE WinISD "beta" (not the Pro version), you can see how box size and tuning effects how low your bass can reach.
              You can basically pick ANY driver, and just click on and type over the THREE values for Qts (0.46), Vas (4.2 - IN CUBIC FT., not liters), and Fs (47).

              Unfortunately, that 12A-II can't get too low in 1.35 cu.ft. (doesn't matter much if it's sealed or ported when it's that small). It'll reach 80Hz, but can't really do even 60Hz well. You'll be losing the bottom octave of most music. To get full bass (down to about 40Hz - for music) you've got to up the size into the 3 to 4 cu.ft. range (and use a port tube).

              Also, your other drivers don't seem to have any graphs available showing how their freq. response and impedance change over the freq. range. Without that info, you're just shooting in the dark trying to get a crossover to make them sound decent. For a "loud" system (speakers that would be OK for out in the garage/shop), you could go w/the woofer (but in a bigger, vented box) and the horn. For a more refined home type system (with less output, but wider and smoother freq. range) you'd use the mid (but THAT one is hard to work with unless you can find FR and Z (impedance) data. The Z data can be fudged, but the FR curve would be best to have) and the EMIT tweeter. Again, w/out FR and Z curves for the tweeter, it's kind of just trial and error.

              Comment


              • #8
                You can learn a lot by looking at the 2 PDF files for your 12" woofer (maybe you already have).
                The box you said you built is probably closest to the last one which is NOT designed to go very low. It actually says "high pass no lower than 80Hz", meaning that in THAT (1.3 cf vented) box, it won't even be able to play well below 80Hz.

                You want something (for full range music) like the LARGE vented box that plays low. (It's around 4 cf.)
                Using a pair of 4"id port tubes that were each 5" long would get you down to around the mid 40Hz range, which should be OK.

                Also, YOU list the driver's sensitivity at 98dB (and Eminence probably does too . . . ), BUT if you look at it's output graph, you can see that it really only plays that loud above 900Hz (actually hitting a max of over 102dB near 2.2kHz - but YOU won't be using it that high up). YOU are more interested in its level below 1kHz, which is more like maybe 97dB, AND (due to a phenomenon called "baffle step") that MIGHT only deliver something as low as 92 or 93dB in a real world application.

                A good starting pt. to roll this guy off around 1.5kHz is a 2.0mH series coil w/a 12uF shunt cap (to ground), and a 10ohm+10uF Zobel.

                290-408.FRD
                290-408.ZMA
                Click image for larger version

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                Comment


                • #9
                  Originally posted by Chris Roemer View Post
                  You can learn a lot by looking at the 2 PDF files for your 12" woofer (maybe you already have).
                  The box you said you built is probably closest to the last one which is NOT designed to go very low. It actually says "high pass no lower than 80Hz", meaning that in THAT (1.3 cf vented) box, it won't even be able to play well below 80Hz.

                  You want something (for full range music) like the LARGE vented box that plays low. (It's around 4 cf.)
                  Using a pair of 4"id port tubes that were each 5" long would get you down to around the mid 40Hz range, which should be OK.

                  Also, YOU list the driver's sensitivity at 98dB (and Eminence probably does too . . . ), BUT if you look at it's output graph, you can see that it really only plays that loud above 900Hz (actually hitting a max of over 102dB near 2.2kHz - but YOU won't be using it that high up). YOU are more interested in its level below 1kHz, which is more like maybe 97dB, AND (due to a phenomenon called "baffle step") that MIGHT only deliver something as low as 92 or 93dB in a real world application.

                  A good starting pt. to roll this guy off around 1.5kHz is a 2.0mH series coil w/a 12uF shunt cap (to ground), and a 10ohm+10uF Zobel.

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                  Chris , thanks I can "see" the graph better as you explain it . It makes more sense after that little lesson . I tried opening the "FRD" / "ZMA" files , will that WIinISD allow me to open those files ?

                  Comment


                  • #10
                    WinISD will allow you to model a woofers response in a box if you have the t/s parameters for that woofer. WinPCD will allow you to view frd files as well as see what happens when you add crossover components like Chris has suggested above.

                    Comment


                    • #11
                      The .frd / .zma files are simply that GRAPH (it has 2 curves) converted into 3 columns of text data (you can view them with something simple like Word or Write). The BOLD (red) line is the way the driver's output rises and falls w/changing freq. (20Hz on the left side, going up to 20,000 on the right) and you can read those values in the .frd file.

                      The .zma file (the changing impedance - which we haven't even talked about yet) is the light curve (which you read against the ohms scale on the right hand column).
                      So . . . (and a MAJOR reason why a generic "off-the-shelf" XO (crossover) won't work on most speakers, and an even MORE majorly reason why a simplistic "1st order" filter (basically an XO that just uses a single coil (inductor) in-line w/the woofer) often stands no chance whatsoever of rolling off the top end of a woofer so it can hand off duties to a tweeter (or midrange)), you can see that even though this woofer is referred to as "8 ohms", in reality it's almost NEVER 8ohms (except in 2 places: down around 23Hz, and up near 6kHz), AND in the area you'd like to roll it off (around 1.5kHz) it's actually around 15ohms (about DOUBLE of what you'd expect). Also you can see that it even goes below 8 ohms in many places.

                      WAY up on the top end (20kHz) it's around SEVENTY ohms! That doesn't matter all too much 'cause it's got no output up there anyway, but you can see that just below 50Hz it's around 80 ohms. THAT's why it's next to impossible to roll off the bottom end of most drivers w/a simple cap. MANY (newbie) guys on here want to limit the bottom end of a driver that really can't handle stuff below 100Hz - like for the small box you made for that 12" where Eminence says not to let it get any of those bass notes or it'll really sound bad. Well, you'd need a very, very large cap (sized to 80 ohms, not 8) to filter its output down there. Even if big caps were free, the worse problem is that you'll never get a nice rolloff curve when the driver's impedance isn't close to linear - meaning where it's really going up and down a LOT.

                      Those F/Z files I posted aren't really for you (at this time), I just traced that graph and threw them on there in case someone else (like J.H. maybe) wants to fiddle w/a filter for you.

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