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[Antone Atmarama Bajor]

     Hey Les I haven't been searching but I do think there are other small DXF viewers out there if you look around.  But I agree Dialup SUX.

Antone-

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[Dave Rickard]

Rory Buszka wrote on Mon, 20 March 2006 07:04

The wasted space I'm talking about is on the baffle. Very little of the front of your enclosure is made up of radiating area. If you removed the LAB12's, I imagine you could cut holes large enough to fit a pair of 15" woofers. The trend today seems to be minimizing the frontal profile of subwoofers so that many can be stacked together. You could keep the internal volume of your cabinet the same and simply make it deeper, like EAW has done with their NT series subwoofer, and it would allow you to make the front narrower or shorter, with the Lab12 woofers side by side or in that "clamshell" configuration. It looks like your cabinet was styled and sized to be a bass guitar amp instead of a professional subwoofer. "Where there's a solution, a problem can't be too hard to invent." Rory Buszka

Perhaps you are inventing a problem?

Dave

[Antone Atmarama Bajor]

     Well it is my personal 5 string Bass Guitar rig.  I drop tune to a 27.5Hz A,  thinking of going to a low F#.  The cabs maybe a little too low distortion depending on ones personal taste.

    I wanted to make sure the thing was easy enough to move  Making it deeper and taller probably would make it harder for one person to handle.

    I see your point if one wanted to make a tight packed array of them it would be better too have a slimmer face.  On the same note It wouldn't be so good for conserving stage space for a Bass rig (It already eats a lot of space).

    I could design a much slimmer version of the cab if anyone here thinks they would actually want to build them.

I think the current facial dimension gives a pair of the BS's a bit of gain above the mid 50's since it acts like a baffle board.

    On a side note.  I suggest tightening the binding posts on the LAB12.  I've found a few that are a little loose. Or some that cause problems when the driver is being driven hard.

Antone-

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[Antone Atmarama Bajor]

     The BS really doesn't have a home, Its not practical for most homes.  Its almost not useful for Pro audio.  I think its more practical for Studio or, cinema LFE.

    My original design objective was to get enough Sub extension to compete with on stage SPL's of Electric Guitar.

    I do own 8 BT7's so I'm covered down to ~28Hz for "Pro Audio"

    If I had the cash I would love to play with a gang of DTS-20s.

    If you wan't High output at 20Hz In a PA  I think the BS and the DTS-20, or a Contrabass are among the few options available.  I don't think there has ever been a demand for 20Hz in PA I'm sure it would freak a lot of people out.  A lot of bartenders wouldn't appreciate their top shelf liquor getting rattled over.

    Going with some of the other High excursion drivers like ADIRE and McCauly Acoupower neomax would require much larger enclosures.  For similar output levels.

Anyhow thats about all I have to say about that.  If you want better LFE use 12 5HP fans and a bellows system like Toms.

Antone-
   

[Les Webb]

What's the max SPL of a single BS-212?

[Antone Atmarama Bajor]

At What Frequency???  Max SPL is a meaningless 1 dimensional number.  If you wanted you could say max spl happens at the 1 Khz peak that the driver exhibits.  I think its almost 10dB hotter than average.  But would you want to listen to it there?

    If you follow the link to the frequency response chart add about 26dB at any given frequency and that should be the MAX RMS SPL for one cabinet at that frequency.  Think useable Power Bandwidth Add 3dB more for Peak.

    The cab was originally conceived as a 4 Driver single cab.  But it quickly became obvious that a 2 2driver cabs would be much easier to move.

    2 BS-212's have almost the same output as a JBL Dual 15 or single 18 cab up to ~ +120Hz.  The place where the BS Takes over in SPL around 40-50Hz.

Antone-  

[Les Webb]

I was thinking of using it for what you built it for, a bass cab.  I have a 4x10 SWR that should do well above 80hz or so.  What will the BS212 do from about 80hz down with a high pass at 25hz?  

The reason I asked about the max SPL is Rory Buszka comments got me thinking they might could be used for FOH subs in a small system.  

What do you think?  No real pro applications, just a rock style church praise band. Maybe two or three per side?  What about a slimmer version?  Would that work better than the current design?

BTW I got the viewer downloaded and am pretty pumped about building the cabs. They look like a fairly simple build (I'm a carpenter/cabinet builder).  Any hints on building materials/techniques?

Les

[Antone Atmarama Bajor]

     Hi Less.  It looks like the SWR may be a good match for the BS-212.  Your cab will do 126 dB RMS across its bandpass.

    You would probably want to adjust balance to taste.

    They are quite clean sounding.  You can High pass them @ 20Hz (or tad lower) without any problems.

    If you are a carpenter than you are years ahead of me with cabinet building experience (This was very hard work for me).  I simply screwed all of the glue blocks into the sheets of ply with wood flooring adhesive in between it for an airtight seal but to maintain flexibility while building (it doesn't smell so good.  The one thing I recommend are lots of good long clamps.  

    You may want to figure out how to mortise it.  Taking away the glue blocks will change the internal dimensions slightly.  Just keep the ports side glue blocks or you'll change the tuning.

    Since it was a prototype situation I used Marine grade ply.  It was a little soft.  A void free birch would be better.

    And after you fire them up check for leaks they will be apparent.  I had to caulk some of my T-nuts from inside.  This was due to the fact that the gaskets that come from Eminence have big notches in them for the mounting screws and any gap in the T-Nut channel can chauf.

    Were you thinking of using some of them for a church system as well or are yo thinking of using 4-6 for just your bass rig.

    You will get the power alley lobes and nulling happening if they are separated.  But this is true for any subwoofers.  for a bass rig I wouldn't separate them  I would have them close together for mutual coupling.  

    I like even numbers so I would say 2 or 4 per side.  Your gains are easyer to think about.  A pair of them are as efficient as a dual JBL 2225 15" cab, and go much lower.  So Small PA Yes they are capable.  I think 2 per side wouldn't be embarrassing  depending on the church size.  

    Keep in mind RMS spl @ 20Hz for a pair of BS-212's is ~ 119dB @ 1600Watts.  If you had four in a cluster you could get +6B output with 3200Watts.  You will certainly be able to find rattles in your church.  If you build them run a 20Hz sine wave through them and walk around you can find the nulls and modes @ 20Hz really easy.  Its fun.

    I'll think about a slimmer version of the cab It will have to become deeper  and I'll have to redo the porting.  I think the current one is ~32" long.

    If you haven't seen here is a link to photos of the BS

http://srforums.prosoundweb.com/index.php/t/9654/8490/

 http://srforums.prosoundweb.com/index.php/m/94261/9564/0///8 490/#msg_94261

    Hope some of this helps.

    On a side note electric bass pickups depending on placement from the bridge have a 6dB per octave low end roll off that starts at a point relative to the bridge distance.  I other words your Lowest fundamentals do not have proportional representation across the fretboard.

Don tillman has a really good pickup response simulator at:
www.till.com.

I'm working on a special EQ compensation curve specific to my bass using an integrator and a Highpass filter.  I let you know how it turns out.

Have fun  

Antone-

    PS tighten the binding posts on the lab12 drivers.