AN Super 12 cast enclosures?

[Doug DuBose]

I am looking at the Chang Shadow SD12 enclosure and wondering if I can get by without BSC ? Has anyone built this horn?

[Scottmoose]

I'm afraid the Audio Nirvana drive units won't work in the Shadow cabinet; they need a much larger box to offer acceptable performance. Sorry.

[Doug DuBose]

Thanks Scott. Has anyone modeled this driver for a back loaded horn or had any experience with the Karlson enclosure. I am trying to avoid a BSC filter.

[Scottmoose]

The Karlson would probably be the best compromise in terms of enclosure size -a back horn would be need to be huge. This is not a driver that works in anything other than a large / very large box (assuming a reasonably accurate presentation). You may find you need a shelving filter anyway to cope with the rising response inherent to the driver.

Assuming the factory specs. are accurate (I have reservations), then something like CSA's own 13.6ft^3 cabinet, with the vents damped as required to prevent any underdamped 'boom' should do OK. Otherwise, I'd go with a classic BR alignment as the extra Vb will give you more flexibility to play with, esp. WRT driver specs., 22.78ft^3 cabinet, with vent CSA = Sd & damp to taste from there.

[Doug DuBose]

WAF isn't a factor as my partially finished basement is my workshop/listening room. I am leaning toward the Karlson at this point. I would like to use the efficiency of this driver to its full advantage. My favorite amps are a 4 watt SE807 and a 17 watt class A triode. I would rather add a ribbon tweeter and a first order crossover at around 8k than all the garbage in the notch filter discussed in another post.

[Scottmoose]

Freddy is our resident Karlson-bod, but FWIW, I'd suggest looking at the K15 given the high Vas (& potentially high Q in practice) of the AN driver.

You may still require a shelving filter to tame the rising response of the driver, as off-axis listening with a Karlson is likely to be problematical & there's only so much it can do to boost the low-end. Alternatively, if you've got corners available in your workshop / listening room, blank them off at 45 degrees (or whatever), thus turning them into large built-in BR enclosures & making it much easier to obtain the ~23ft^3 apiece the classic alignment referred to above needs, and also circumventing any circuitary requirements.

[Doug DuBose]

I'll start with boombox alignment from CSA and go from there. Thanks for all of your help and suggestions. Life is much easier and this hobby cheaper when we don't have to learn things the hard way.

[freddi]

those TS look good nuff for K15 - BSC won't be needed

[Doug DuBose]

Thanks freddi. I have seen the plans on the Karlson site. Do you have something better?

[freddi]

the standard Karlson 15 plan from January 1954 is in this tread along with an update to port and shelf spacings. I would build it to 1954 spec then adjust by ear the port and shelf. There's trim specs too.

Karlson Plans