2-15 Port Placement Question

[FerruleCat]

I'm planning a refurb of a Bassman 2-15 cabinet, and I plan to install port tubes, rear mounted. I've identified two approaches that could work: one using four 4" ports and one using two 6" ports as shown here:

The drawing illustrates how the port profiles would overlap (or not) the drivers at the front of the cabinet.

The four-port option reduces my port velocity slightly, and is actually cheaper than the other, but not by much. It does, of course, involve more cutting, but that's not a big deal.

Aside from those considerations, is there a clear advantage to one design over another? I'll be running up to 500 watts using a PF800 head.

Thanks.

 

[will33]

I'd do the 4 corners.

Symetrical pressure load on the drivers. Maybe some of that chimney effect cooling Duke describes. Also gives the option of plugging 1 or 2 for alternate (lower) tunings.

 

[FerruleCat]

Thanks. This would work...

 

[ArenW]

So, how did this project end up? I've read that this could be a potential sonic disaster with this cabinet, but I've got one and had wondered if anyone had experimented with porting.

 

[FerruleCat]

So, how did this project end up? I've read that this could be a potential sonic disaster with this cabinet, but I've got one and had wondered if anyone had experimented with porting.

I haven't done it yet, but I have at least stripped out the old drivers and the cracked plastic handle cups. The drivers were fried, so I couldn't get a baseline sound sample. The WinISD models look workable, so I'm confident that the reconfiguration will improve on the stock performance. I'll seal off the slot port, then add four 4" rear ports with tubes 6.25" long. This will tune the box to about 48Hz; a pair of Dayton PA380s in this box will handle *EDIT* 520 watts before fartout and produce a maximum 125dB on a reasonably even response curve.

The only part I'm actually dreading is redimensioning the handle cutouts. I'll have to both narrow and lengthen the holes.

It's going to be right at $200 to refurb it. There hasn't been any urgent need for this cabinet, so I've been letting it sit. but I'll be doing it over the next 4-6 weeks.