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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Subwoofer FUD Forum Archive => Topic started by: Shivraj Persaud on October 30, 2008, 12:32:22 am

Title: B&C Subs - merged
Post by: Shivraj Persaud on October 30, 2008, 12:32:22 am
I am building 2 SUB215 using B&C's plans on their website. I will post pics of this project as I work on it.

The website says the plywood or material will be 50mm or about 1". Do I have to use MDF board for this ? Or is it possible to use 0.75 inch plywood just making sure the ports are 2", and the internal volume remains at 300 liters.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Jim Ferrari on October 30, 2008, 06:09:50 am
The plans I saw refer to 25mm plywood, properly braced. I would never use MDF for any box intended for mobile use. It's not rugged enough and doesn't like to get wet very often. Good luck.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Steven Geist on October 30, 2008, 09:55:07 am
You should be able to order 1" (25mm) plywood from a lumber yard.  It will probably have to be special ordered.  Or you can do two .75" sheets.  Personally, I think with proper bracing .75" will work.  Make sure you get 13 ply birch.  So long as all the internal dimensions are the same you will be ok.  Plywood also has the added bonus of being a little lighter than MDF.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on October 30, 2008, 02:29:11 pm
Yes 25 mm is approx 1" sorry for the mistake 50 mm is the vents. 0.75" plywood is very rigid and easy to work with. I guess thats the only way to go. 1" plywood will be too expensive.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Ivan Beaver on October 30, 2008, 08:03:33 pm
A 2" vent is going to whistle on you.  You need to make them quite a bit larger AND deeper in order to get decent bass performance.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on October 30, 2008, 08:14:04 pm
did you see the plans ? its 2" but times appx. 30 inches on both sides.

Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Ivan Beaver on October 30, 2008, 08:29:17 pm
No, I did not look at the plans first, my bad. Embarassed

I was just going by your description and it sounded (my bad) like you were talking about a 2" port that was .75" deep,

Sorry.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on November 05, 2008, 08:58:22 am
isnt 3/4" plywoood really 18mm ? I worked with it before and it was not exactly 3/4".

Thanks.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Ivan Beaver on November 06, 2008, 07:27:08 pm
Shivraj Persaud wrote on Wed, 05 November 2008 08:58

isnt 3/4" plywoood really 18mm ? I worked with it before and it was not exactly 3/4".

Thanks.

And most "3/4" isn't 3/4 either, but slightly smaller. 18mm is actually .708", IF it is actually 18mm.  It does vary a bit.
Title: B&C Subwoofer Cabinets
Post by: John Shelbourn on November 11, 2008, 03:12:48 pm
I am really considering building (4) B&C 215 or sub 218 subwoofer cabinets.  Does anyone have any experience with these? Pictures, plans, etc.  Also, what would you recommend for amplifier(s)?  The sub 215's seem to have better specs; would it be smarter to build the sub 215 instead of the sub 218?

I would love to build lab subs but we are a weekend warrior band, I currently own 4 ls800p's and a pair of Mackie srm1530's.  I love the system but when I start crunching the numbers they seem to get pricey when trying to expand your pa, not to mention the power cables needed.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: John Shelbourn on November 11, 2008, 03:56:53 pm
Why did you choose the SUB215 instead of SUB218.  What are you powering the cabs with?  Did you get plans in feet and inches?

Thanks!
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on November 11, 2008, 05:57:56 pm
John,

I was trying to get a powered sub system. The QSC HPR sounded great in the store and its a great sub but its too pricey to expand, I figure I need about 4 of those. So I decided upon B&C SUB215.

I chose 215 cause the specs are pretty good. I would really like to hear what 134db long term sounds like. I built a lab sub before but its not practical, cant put that in my house. Play it with a 60 RMS amp and the neighbors complain  Laughing . Plus I like the sound of front loaded subs. I will be taking that apart to use the drivers in 2 sealed boxes.

I am getting two yamaha p5000s amps to push each sub. That should be sufficient. QSC is simply too pricey, plus I think Yamaha quality is right up there with QSC.

I still didnt start building them, I just got the wood.

Oh on inches and mm, I converted everything to mm to make it simple to use teh plans. Dont try to conver it to inches, it will be nuts. Plywood is 18 mm thick, just need to make minor adjustments like at teh port to keep it at 2 inches.





Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:48:23 pm
here's a pic
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:49:23 pm
another
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:53:11 pm
driver
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:53:47 pm
driver
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:58:39 pm
pic
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 15, 2009, 08:59:16 pm
pic
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Cosmas Bain on March 15, 2009, 09:01:52 pm
looking nice
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Elliot Thompson on March 16, 2009, 12:50:10 am
That is a nice classic design.

I would strongly suggest you add more bracing. You have a lot of large panels that are going to "ring" when the right tone comes to pass. Also, damp the rear wall.

Adding a 2 by 4 or 2 by 2  from the front of the baffle board to the rear wall will prevent the "flexing affect" which very when boxes are as deep as yours.

It looks around 762 mm deep.

Best Regards,

Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Marjan Milosevic on March 16, 2009, 06:57:06 am
You didnt make any space for mounting a grill.
You should have placed the baffle some 5cm towards the back of the box.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Elliot Thompson on March 16, 2009, 07:22:36 am
Marjan Milosevic(MarjanM) wrote on Mon, 16 March 2009 10:57

You didnt make any space for mounting a grill.
You should have placed the baffle some 5cm towards the back of the box.



It seems cost is the motive, after reading the thread. So he might go with...

http://akamaipix.crutchfield.com/products/2003/125/h125g12-fp.jpg


Worst case scenario he can attach shims as a frame for a full size grille to sit in.


Best Regards,
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on March 16, 2009, 04:49:48 pm
yes I bought a pair of grills from parts express, my friend is cutting it for me right now. The grill wasnt long enough so I had to take some from the width and add to the height.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on April 02, 2009, 07:08:03 pm
finally fired it up, only one of these sounds amazing. Running it through a yamaha p2500s bridged, gotta turn gain all the way up, pretty hard to get it to clip though ... but its really loud. any thoughts on amp?
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: George Friedman-Jimenez on April 04, 2009, 03:56:35 pm
Nice job. How much does it weigh with drivers?
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on April 10, 2009, 11:56:26 pm
it weighs about 140-150 lbs, not light, but good dimensions, not that high but deep.

Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Douglas R. Allen on April 13, 2009, 07:23:12 pm
When you have them all done could you post a picture?
Also a link to the plans?
Douglas R. Allen
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: George Friedman-Jimenez on April 13, 2009, 09:34:45 pm
http://www.bcspeakers.com/suggested.php?id=0000000009
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Shivraj Persaud on April 25, 2009, 12:41:37 am
question about power amp, thinking about building more of these subs and powering them with a crest ca18 or ca12 .. cause I want to run them in parallel to get more out of them. Looking at the impedance response curve I can get down to 2 ohms. But how would you provide power to the amp, I see these amps require up to 60 amp service, can you build or buy something that can store the power? like a capacitor?
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Duncan McLennan on April 25, 2009, 09:29:50 am
No... you just use a power source that has a large enough supply.

The amplifiers will not draw 60A.  Check the spec sheer for ratings for 1/3 and 1/8 power.  If you've got enough subs/amps the most you should be drawing is about 1/8 (that's the average power the amplifier draws when you're just barely touching the clip lights).

I would think you'd be more than fine running each one on a 15 or 20A circuit.
Title: Re: Planning on building 2- B&C SUB215 subs
Post by: Reginald Dennery on May 06, 2009, 04:34:03 pm
Very nice build.
You should have some nice kick bass coming out of those