How about a monster baby sub?

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  • JonMarsh
    Mad Max Moderator
    • Aug 2000
    • 15213

    How about a monster baby sub?

    Well, you know, I really like the sound of the Aerial Stryke, but my Gawd, that puppy is big and heavy. It's made me think a lot about how to get a "monster" sub in a smaller box.

    So, yesterday, in my copius spare time during lunch, I got out my copy of Unibox spreadsheet, entered some driver parameters, and I think I've hit upon an interesting solution, using the Blueprint 1203. My calculations show that in as little as an effective volume of 40 liters, a sealed box will have an Fs of about 40 Hz, but more importantly, a Q of 0.5, which is critically damped. (the Blueprint 1203 is a low Qts driver, nominally about 0.29) Now, with a straight forward shelving EQ, the response roll off can be lifted to be near flat anechoic with 8-10 dB of boost, maxing at 20 Hz. Since the in room response increases the low end some anyway, probably 6-8 dB of boost is all that should be used. Note, this is better than a comparable effort with a Shiva because of the high cone mass, large magnet/high BL product, and low Q of the Blueprint driver.

    Back of the napkin calculations show this should be doable in one of the Woodstyle sub cubes I have lying around, asumming a lot of extra internal bracing- subtracting for the bracing and driver, from the nominal 61 L, should leave enough box volume.

    I've got a Sumo crossover hanging around that I bought from a friend in MO- he wanted to get out of separates and get into a big receiver (I dunno, it must be something in the water there, maybe too much fluoridation), so I "helped" him out by taking it off his hands- zero feedback high pass buffer, and nice frequency options- should work for this. And there's a Marchand Basis under my bed that I need to finish assembling; that should handle the LF EQ just fine.

    Power requirements calculate out to 500 - 1 kW. I knew there was a reason we've been on an Aragon buying binge the last year. Sounds like a Palladdium or 8008 would drive it handily (clips at around 600 W balanced out at 8 ohms, about 1 kW at 4 ohms- gee, the Blueprint is 4 ohms, how convenient!) Should hit about 107 dB at 20 Hz, with 45 mm p-p Xmax. A cool thing about the Sumo crossover is that it has stereo and mono bass outputs, both positive and inverted polarity, so it can bridge amplifiers into mono without any extra circuitry. If you do this with an ST or BB, be sure to strap the output speaker grounds together.

    Well, when I get back from the trip next week, I think I'll have to put one of these Blueprint drivers on order.

    Can anyone think of a better high excursion twelve for this concept? I'm all ears, at least for a couple of weeks.

    Regards,

    Jon




    Earth First!
    _______________________________
    We'll screw up the other planets later....
    the AudioWorx
    Natalie P
    M8ta
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    In Development...
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    Resistance is not futile, it is Volts divided by Amperes...
    Just ask Mr. Ohm....
  • Jack Gilvey
    Senior Member
    • Aug 2001
    • 510

    #2
    Hi Jon,

    I played with the 1203 in the Linkwitz trasnform spreadsheet and the results were extremely promising in even tiny boxes. The motor on the -03 series (in the 1503) was just Dumaxed at 25.89mm Xmax, so it's quite a bit more than the rated 45mm P-P, as well. The 1803, at $249, seems like a better buy (that's what I'll order), but I can't imagine getting better sound at useable SPL in a small cab than with your idea.
    btw, I'd love your input on alignments/uses for the 1803...

    Comment

    • Andrew Pratt
      Moderator Emeritus
      • Aug 2000
      • 16507

      #3
      Jon i've been reading up on your idea's for the 1203 driver and it seems that you favor the 81 liter ported box tuned to 25 hz (29" long 4" dual flared vent). Would you still advise that's a good design? How much power would you recomend for that box? I was thinking of getting one of the 380 watt plate amps when they come back in stock at Solen or CreativeSound.

      Question 2.

      I'm limited in height to 19" total which means that a 4" flared went plus the driver isn't going to work on the front so I guess I'm going to have to port on the back which isn't a big deal...but if i have to use an elbow do you have any suggestions on how to make that solid? Also would dual 3" be better then a single 4". dual 3's have slightly more surface area but they'd need to be a little longer which would be an issue as the 4" is already very long for that volume.




      Comment

      • JonMarsh
        Mad Max Moderator
        • Aug 2000
        • 15213

        #4
        Hi Andrew,

        With a ported approach, such as the 81 liter box, the only construction approach I'd feel comfortable with is an Aerial SW12 clone, like our Aerial Stryke, but scaled down. I'm not a believer in curved or elbow ports.

        4" port is barely adequate; 6" would be better, but impossibly long for the box. 4" need to be 40-42 cm or longer depending on desired Fs (24 Hz ~ 42 cm). Particularly with high vent velocity you don't want elbows or other oddities. TL designs get away with bends because the cross section is so, so much larger- bigger than the driver Sd.

        Other than 3 dB more output, if you've got to go small, sealed with a big amp is probably the way to go. I'm still going to do that with one, but just haven't had the time! Also have been considering putting two in a 3 cu ft box. Would be a bear to pick up, though!

        ~Jon




        Earth First!
        _______________________________
        We'll screw up the other planets later....
        the AudioWorx
        Natalie P
        M8ta
        Modula Neo DCC
        Modula MT XE
        Modula Xtreme
        Isiris
        Wavecor Ardent

        SMJ
        Minerva Monitor
        Calliope
        Ardent D

        In Development...
        Isiris Mk II updates- in final test stage!
        Obi-Wan
        Saint-Saëns Symphonique/AKA SMJ-40
        Modula PWB
        Calliope CC Supreme
        Natalie P Ultra
        Natalie P Supreme
        Janus BP1 Sub


        Resistance is not futile, it is Volts divided by Amperes...
        Just ask Mr. Ohm....

        Comment

        • Andrew Pratt
          Moderator Emeritus
          • Aug 2000
          • 16507

          #5
          Jon by small are your thinking 40L and how much power are we talking about?




          Comment

          • ThomasW
            Moderator Emeritus
            • Aug 2000
            • 10934

            #6
            how much power are we talking about?
            Oh, not much. Anywhere from 500-1000 watts will be fine....... :B

            And no I'm no kidding............ 8)




            theAudioWorx
            Klone-Audio

            IB subwoofer FAQ page


            "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

            Comment

            • JonMarsh
              Mad Max Moderator
              • Aug 2000
              • 15213

              #7
              Andrew,

              If this is your first long Xmax driver, you need to adjust your expectations re power a bit- because so much of the voice coil ISN'T in the gap at any time, the efficiency suffers- all of the drivers with Xmax in the 20-25 mm range typically need 500 - 1000 watts to reach their potential. Now, due to impedance, that means that power is required at 4 ohms, which makes an Aragon Palladium or similar monoblock a good fit, as it's clip point at 8 ohms is about 600 watts, and at 4 ohms about 1 kW.

              :rf

              Now, you could cut back that power to 250 watts, but then you may as well only have a driver 6-10 mm Xmax, as far as the SPL you'll get.

              Tradeoffs, tradeoffs. High Xmax drivers can do the job in a small box, with the right parameters, but there's no breaking Hoffman's iron law. You'll need some HP to get the job done.




              Earth First!
              _______________________________
              We'll screw up the other planets later....
              the AudioWorx
              Natalie P
              M8ta
              Modula Neo DCC
              Modula MT XE
              Modula Xtreme
              Isiris
              Wavecor Ardent

              SMJ
              Minerva Monitor
              Calliope
              Ardent D

              In Development...
              Isiris Mk II updates- in final test stage!
              Obi-Wan
              Saint-Saëns Symphonique/AKA SMJ-40
              Modula PWB
              Calliope CC Supreme
              Natalie P Ultra
              Natalie P Supreme
              Janus BP1 Sub


              Resistance is not futile, it is Volts divided by Amperes...
              Just ask Mr. Ohm....

              Comment

              • Andrew Pratt
                Moderator Emeritus
                • Aug 2000
                • 16507

                #8
                No problem on the HP issue. Parts Express has its 500 and 1000 watt plate amps on for a very attractive price so I'll get one of those...is the 1000 watt model worth the extra $100US? Its still within budget so I'll likely go for broke and get that. It also has a crude parametric EQ onboard which should allow me to boost the botto m end a bit...which will eat headroom so I guess I've just talked myself into the 1000 watt unit So with that a done deal how large should this sealed puppy be? The Sims I've run show a very small box but I believe you said around 40 L in another thread...




                Comment

                • JonMarsh
                  Mad Max Moderator
                  • Aug 2000
                  • 15213

                  #9
                  My original evaluations for the BPD1203, as in the start of this thread, call for a net volume (subtracting for the driver, bracing, etc) of 40 liters. That's about the same as the M8 box! Overall volume, considering what you must allow for the driver, will be in the neighborhood of 60 liters. It's not critical, and if it's a little larger, it won't hurt anything- will just be a little over damped, and won't need quite as much LF EQ. As long as it's 40 liter or more, a full Linkwitz transform won't be needed because no compensation for LF peaking in the cabinet is required. Just the EQ; I'd start with about 6 dB net shelving boost at 30 Hz; let it roll at the natural cabinet response below that; it will be only about 9-10 dB/octave, due to the low Q alignment; at 20 Hz, it will be about 6 dB down. Depending on room position, room gain, etc, that may be pretty flat in room.

                  The BPD's have high VC inductance, so they will roll off above 75 Hz; depending on your chosen crossover point, you may need a little lift in the upper end for the smoothest blend with your mains. That's what the BPD1503's and the HE-15 required.

                  ~Jon




                  Earth First!
                  _______________________________
                  We'll screw up the other planets later....
                  the AudioWorx
                  Natalie P
                  M8ta
                  Modula Neo DCC
                  Modula MT XE
                  Modula Xtreme
                  Isiris
                  Wavecor Ardent

                  SMJ
                  Minerva Monitor
                  Calliope
                  Ardent D

                  In Development...
                  Isiris Mk II updates- in final test stage!
                  Obi-Wan
                  Saint-Saëns Symphonique/AKA SMJ-40
                  Modula PWB
                  Calliope CC Supreme
                  Natalie P Ultra
                  Natalie P Supreme
                  Janus BP1 Sub


                  Resistance is not futile, it is Volts divided by Amperes...
                  Just ask Mr. Ohm....

                  Comment

                  • Andrew Pratt
                    Moderator Emeritus
                    • Aug 2000
                    • 16507

                    #10
                    Thanks Jon the client is using a Denon receiver so it'll have a fixed 80 hz XO so that shouldn't be too bad.

                    I'll likely just make it 15" cube (internal diamentions) so that'll give me 55L to work with. I think the drivers' 6L and the amp looks to be at least 2-3L so between those and the bracing it should end up being a little over 40 give or take a bit




                    Comment

                    • ThomasW
                      Moderator Emeritus
                      • Aug 2000
                      • 10934

                      #11
                      Andrew

                      The single band parametric EQ in that amp is all but useless. The guy needs a BFD to properly EQ the sub.

                      Yes do get the larger amp...or find someplace that sells the Behringer EP-1500. The fan is noisy but that's a TON of amp for the money...




                      theAudioWorx
                      Klone-Audio

                      IB subwoofer FAQ page


                      "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                      Comment

                      • Andrew Pratt
                        Moderator Emeritus
                        • Aug 2000
                        • 16507

                        #12
                        Thanks Thomas...the 1000 watt plate amp is now on order so I'll give that a go first. His gear rack is pretty close to his seating area so i'm sure the fan noise would be an issue.




                        Comment

                        • Brian Bunge
                          Super Senior Member
                          • Nov 2001
                          • 1389

                          #13
                          Andrew,

                          I'm really interested in hearing how the amp works out for you. I've got some serious reservations about the amp's ability to actually produce 1000W RMS. Hell, even PE can't get the specs right. In the product specs it's stated as 1000W RMS, but in the PDF owner's manual it's stated as 1024W PEAK at 4 ohms. It sure would be nice to get someone to actually test the RMS power output of these amps as well as the 500W version which has the same issues.

                          Comment

                          • Dennis H
                            Ultra Senior Member
                            • Aug 2002
                            • 3791

                            #14
                            Hmmm, I guess QSC is the latest brand for Behringer to go after. Other than the front panel, that EP1500 looks like an exact knockoff of the RMX1450 and the EP2500 looks like the RMX2450. Specs, features, even the back panel layout. They're probably even made in the same factory in China.

                            Comment

                            • Andrew Pratt
                              Moderator Emeritus
                              • Aug 2000
                              • 16507

                              #15
                              I'm going to start building the box this weekend and I got a shipping notice for the amp this morning so I'll keep you guys posted on how it turns out.




                              Comment

                              • ThomasW
                                Moderator Emeritus
                                • Aug 2000
                                • 10934

                                #16
                                Dennis,

                                According to someone on the bass-list; at a recent trade show, one could look inside the Behringer amp and see 'QSC' on the circuit boards..... 8O




                                theAudioWorx
                                Klone-Audio

                                IB subwoofer FAQ page


                                "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                                Comment

                                • Dennis H
                                  Ultra Senior Member
                                  • Aug 2002
                                  • 3791

                                  #17
                                  Verrrry interesting. Has anyone tried those QSC and/or Behringer amps on a full-range speaker? They obviously have power to burn but I'm wondering about the quality of that critical 'first watt.'

                                  Comment

                                  • ThomasW
                                    Moderator Emeritus
                                    • Aug 2000
                                    • 10934

                                    #18
                                    I have no idea about how they sound.

                                    For those wanting more info as to how Behringer works here are some links and a snip from a Q&A




                                    A quote about Behringer's stealing product designs

                                    SNIP-
                                    Can you tell us about Mr Behringer, who copied your products without
                                    licence?

                                    The German Federal Court found him guilty in 1992, he was copying
                                    exactly the Type B Aural Exciter, Type D, and then Type F. He copied so exactly those products, same face blade, used the same arguments in his
                                    brochures, and so then we started pursuits in 1987. And he put on so many arguments to the Court that it took until 1992 to find him finally guilty. In the meantime, he kept on using and using our technology. Then the next product he copied was the 612, a noise gate, and he copied everything so exactly, but from an earlier version, that he even copied the mistakes we had made! But he was hard to argue we didn't have a patent on the 612, but we went to Court because he had copied our manual, page for page, illustration for illustration. So we could show the Court exactly what he did, and were able to bother him for the copyright. He's an unbelievable thief, and then he says that he developed all this on his own, so people thinks he's a good engineer, but all he is a copyist.
                                    Each product is a copy.

                                    Did he copy products from other manufacturers ?

                                    Among others dbx, Bristow, Rockon, Mackie. He comes out with a console
                                    exactly like the Eight-Bus. So he's a very dangerous person. And it's
                                    not allowed in America to form a cooperation to go in trial against a
                                    manufacturer. It's a problem because I play with rules above the table,
                                    he plays with rules under the table: he has no morality, he laughs, he
                                    makes a mockery of business ethics, and it makes me crazy because I could go home and I could sleep, the problem is what he's doing is confusing the market by telling them "Oh, that product is perfect, it works great", but when you analyse the product it's a bad copy. But he's that kind to make great advertising: that's easy for him, because he has no engineering expense. So that's why each one of the products we do now must have patents.



                                    theAudioWorx
                                    Klone-Audio

                                    IB subwoofer FAQ page


                                    "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                                    Comment

                                    • Hank
                                      Super Senior Member
                                      • Jul 2002
                                      • 1345

                                      #19
                                      Wow, makes me want to NOT buy Behringer :evil:

                                      Comment

                                      • JonMarsh
                                        Mad Max Moderator
                                        • Aug 2000
                                        • 15213

                                        #20
                                        Even makes me feel a little guilty about buying my cheapo Behringer microphone. ops:


                                        ~Jon




                                        Earth First!
                                        _______________________________
                                        We'll screw up the other planets later....
                                        the AudioWorx
                                        Natalie P
                                        M8ta
                                        Modula Neo DCC
                                        Modula MT XE
                                        Modula Xtreme
                                        Isiris
                                        Wavecor Ardent

                                        SMJ
                                        Minerva Monitor
                                        Calliope
                                        Ardent D

                                        In Development...
                                        Isiris Mk II updates- in final test stage!
                                        Obi-Wan
                                        Saint-Saëns Symphonique/AKA SMJ-40
                                        Modula PWB
                                        Calliope CC Supreme
                                        Natalie P Ultra
                                        Natalie P Supreme
                                        Janus BP1 Sub


                                        Resistance is not futile, it is Volts divided by Amperes...
                                        Just ask Mr. Ohm....

                                        Comment

                                        • Dennis H
                                          Ultra Senior Member
                                          • Aug 2002
                                          • 3791

                                          #21
                                          To be fair, Behringer doesn't steal all their designs. I'm not aware of anyone else who builds an all-in-one box like the DEQ2496 -- RTA, graphic EQ, parametric EQ, plus a bunch more features -- at any price let alone for $300. It's a helluva deal.

                                          Comment

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