B&C Sub designs

[Kip Conner]

Re: B&C Sub designs

Currently I'm using XTI 4k's bridged at 4 so essentially each cabinet is getting 1600w.

In the near future I would love to replace the 8 ohm and get the 4 ohm version and use one amp per box and then the cabinet would be getting 3200w.

It's hard to see in the pic, but the depth of the port is essentially the internal depth of the box. It would appear that there are three chambers, but they are just braces for the face of the box to mount. I'll try to get a bigger version of the pic and see if this makes sense.

 

[Loren Jones]

Re: B&C Sub designs

Kip, Loren,







I think the phrase used was "an honest look at the simulations" followed by an immediate caveat that no one would build an 80% of SD port.

Thanks for making that more clear Phil. Sorry that in my eagerness to be of assistance I made it seem as though you advocated a huge port design that wouldn't work with reality due to its size.

Loren

 

[Kip Conner]

Re: B&C Sub designs

Although I'm in the middle of a Lab-sub project, I feel a desire for building a sub based on a B&C 21".
For some reason I've had that desire for a couple of years. Totally irrational and unexplainable.

Some day.....

Anybody know of a good design for a B&C 21" that I could drool at?

B&C has two 21" design on their site: B&C SPEAKERS

 

[Alan Sledzieski]

Re: B&C Sub designs

The port depth would be how far the wood goes back under the speaker, put your hand in the port and feel when your fingers go inside and towards the speaker, I need that dimension. Its not the depth of the box like you say, probably closer to 1'' from the looks.

I plugged some numbers with the tbw 100 in that box, using 3 ports 6.5 wide, 2.5 high and 1'' deep. Thats what it looks like you have, the results are pretty bad.

Red is your box as is, blue is with a longer port

 

[Alan Sledzieski]

Re: B&C Sub designs

So no chance of 2 double 18 box's or bigger single 18's?

 

[Phil Graham]

Re: B&C Sub designs

Thanks for making that more clear Phil. Sorry that in my eagerness to be of assistance I made it seem as though you advocated a huge port design that wouldn't work with reality due to its size.

Loren

I do advocate huge port designs I'm also realistic about how large of a port can be tolerated practically. The issue is drivers fundamentally being able to outpace port performance without substantial care.

 

[Bennett Prescott]

Re: B&C Sub designs

So no chance of 2 double 18 box's or bigger single 18's?

Alan,

When we had those suggested designs made, the vast majority who were interested in them were also interested in maximum portability. There are lots of double 18" designs available, but fewer that take a single driver like these.

 

[Kip Conner]

Re: B&C Sub designs

Than the port depth is 0. The two braces that look like chambers are only there to support the face of the box.

I'm not really interested in double 18 boxes at this time because I want to arrange them in a cardioid fashion.

As for a bigger single box, I was to go wider instead of taller and deeper. The depth could add an inch or two if it had to be there, but it starts getting too deep for the quarter wavelength for the rear box of the cardioid arrangement.

 

[Alan Sledzieski]

Re: B&C Sub designs

Then keeping your box dimensions neear the same, I would build this, its the white graph, red is what you have now.

 

[Alan Sledzieski]

Re: B&C Sub designs

Heres the dimensions

 

[Alan Sledzieski]

Re: B&C Sub designs

Than the port depth is 0. The two braces that look like chambers are only there to support the face of the box.

It can't be zero, it would be the depth of the face plate, most likely 3/4, I used 1'', 1/4'' is negligible, its so far off to begin with.

 

[Kip Conner]

Re: B&C Sub designs

So, to clarify... the width is the biggest change in the design modification by going a few inches and increasing the volume. Does it matter if the port walls are part of the bottom panel or does it need to elevated off the ground? Or does "One Flush End" indicate that one port wall will be shared with one of the side panels.

This software looks really great, This and a wood shop would make me a real happy camper! Thanks so much for your efforts, I'll be sure to give credit where credit is due.

 

[Alan Sledzieski]

Re: B&C Sub designs

So, to clarify... the width is the biggest change in the design modification by going a few inches and increasing the volume. Does it matter if the port walls are part of the bottom panel or does it need to elevated off the ground? Or does "One Flush End" indicate that one port wall will be shared with one of the side panels.

This software looks really great, This and a wood shop would make me a real happy camper! Thanks so much for your efforts, I'll be sure to give credit where credit is due.

The port wall can be part of the panel. Flush end describes the visible end, it doesn't stick out, Heres my double 15


dam, cant see the port but its even with the bottom, just like your sub

 

[Kip Conner]

Re: B&C Sub designs

So I took the new dimension and came up with this... the one dimension that isn't noted is that the depth of the additional wall 7" which would be the port depth. Hopefully I did this right!

 

[Alan Sledzieski]

Re: B&C Sub designs

I know you said you were thinking of getting 4 ohm 18's. Then use 4 xti's bridged. You would be further ahead by getting rid of the xti amps and getting 2 amps that do 4 to 5 k bridged. like crest ca 18. crest pro 8200, Old crown macro 5k's. We have found the xti's to be one of the worst sounding amps around when compared to what I have listed. I know some people that won't use them on monitors.

You have 4 of these 18's now from the looks of it?

Plus if you ever decide to go into double 18's, you would be all set with your 8 ohmers.

When I get a chance I'll model a double 18 box around your 18's and see how it looks.

Also buy this program. If I can figure it out, anyone can.

US Speaker - Eminence Speaker Cabinet Design Software for designing professional speaker cabinets.

 

[Alan Sledzieski]

Re: B&C Sub designs

So I took the new dimension and came up with this... the one dimension that isn't noted is that the depth of the additional wall 7" which would be the port depth. Hopefully I did this right!

View attachment 4604

I'm about to leave for a show, I'll take my camera and take a better pic. Basically when you stick your hand through the port, you will have a 7'' deep piece of wood before your figers curl around to reach the speaker. Yes taking the braces out of the port is correct, your original box is a 3 port box

 

[Kip Conner]

Re: B&C Sub designs

I was looking at those as well as PL380's. I just happen to have some of these XTI4k's laying around and had only needed one more to make this system work as is- I picked it up here on the board. The overall plan is to move to a Power Switching Supply Amp. Most of my shows need to run on 2- 20amp circuits, that's my biggest obstacle.

 

[Alan Sledzieski]

Re: B&C Sub designs

I was looking at those as well as PL380's. I just happen to have some of these XTI4k's laying around and had only needed one more to make this system work as is- I picked it up here on the board. The overall plan is to move to a Power Switching Supply Amp. Most of my shows need to run on 2- 20amp circuits, that's my biggest obstacle.

Never used a pl380 so I don't know, My crest 8200's are working great on the subs. I got away from the heavy Iron also, getting to old to move 600 lb amp racks around. I have 23 kw 12 spaces now ; )150 lbs.

 

[Alan Sledzieski]

Re: B&C Sub designs



Plus 2 more 8200's for monitors

 

[Alan Sledzieski]

Re: B&C Sub designs

I see the pl 380 is a class d amp, Never heard a good one in my life, no guts, may just be me, but I would have to try one before I ever put that much cash down on one.