1215A Plans

[Old Guy]

Sorry that's actually a dual 18". The point was that a W-bin gets really huge when used for low bass. Even that box is only good to about 50 hz.

[LICORNE]

Here is a folded horn reinvented Canadian style.

I hope I'm not mistaking.

The cabinet comes with a 21' woofer.

http://www.tr.ca/2006/english/produc...ig-fd-121w.htm

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[Old Guy]

That is a good example of the type of design that's become more popular.

With a 21" I would have real concerns about the dynamics of the response though. Bigger is not necessarily better. And I suspect that's still a pretty short horn.

[LICORNE]

Here is the folded horn model with 18" woofer specs. The 21" model specs are not available for now.


http://www.tr.ca/2006/english/produc...es/fd-118w.htm

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[Steve Mac]

I like the ad:
it gene-rates an astonishing bass (down to 36 dB!).

I'm tellin ya, nothing beats the Jensen Imperial horn as a sub. I built one for my Dad with the Hartley 24"(think it's actually ~22").
http://www.steevee.com/jensen/jensen.htm
The hartley woofer...I swear is one great speaker.
It took a long time to work through the dimensions but I've got schematics up there that are easier
to read and construct than the originals.

Also www.decware.com has caught on to the
Jensen imperial design as well.

[bowtie427ss]

Steve Mac, What size driver was the imperial originally designed for?

There are a pair of those, exceptionally well built, at Audio Classics in Vestal, NY. They are loaded with 15 inch woofers. They've tried to send them home with me a few times, but i just don't know enough about them. I'm wondering what the original plans/drawings were rendered for in respect to woofer size. Were the ones you linked us to scaled up?, or are the ones in my neighborhood scaled down?

The pair here in my neighborhood are beautifully finished inside and out in golden oak. They belong to the company president, story goes that he spent a small fortune having them built. They'd probably let me bring them home to audition as the VP is a long time good friend, but they'd be a monumental moving task, and not really practical unless they dip well into that bottom octave unlike all of the other bass horns i'm familiar with, not to mention the fact that i need them like i need another hole in my head.

I'd be happy to find them a new home, even if it's not mine.......... i can always use the brownie points with those guys.

[bowtie427ss]

I found a couple links that offer some explanation, it appears to be a visitor limited site, if it doesn't work immediately try again later, some good vintage literature.

http://au.geocities.com/footstony/jentech1.pdf

http://au.geocities.com/footstony/imp_diy.pdf

Any opinions on the use of 416's or 515's in the imperial enclosure?

[GM]

Greets!

It was designed as a 'one size fits all' of their 15" drivers (medium high Qts), so either significant EQ or a redesign is required for low Qts drivers such as the 416/515 series, though the 515-8G or similar driven with a low DF amp typical 'of the day' or adding series resistance as required if SS driven will in theory be a ~perfect match.

GM

[bowtie427ss]

Thanks GM,
Sounds like the imperials are best left for a vintage Jensen collector.

Please forgive me for hi******* this thread, but i'm looking for a good bass horn winter project, i like to build boxes when i can't play outside. Can anybody offer experience or opinions on Mike Frye's "210 split"? basically a halved version of the 211.

I don't currently own any large format horns/drivers, since i prefer to cross that horn/driver higher than 500hz, would it be impractical to persue that route with the intention of using the 511/802 combination on top?

[GM]

Greets!

You're welcome!

Can't say as I agree with your conclusion unless someone's not willing to commit a 515-8G or similar to the project, but as always, YMMV.

The problem with orienting the 210/2 vertically is the long distance between the LF and HF driver that requires a very low XO point to get a good acoustic summation through the XO BW, which ideally needs to be < WL/pi - 1 WL max, so if there's enough floorspace, better to lay it on its side and best to change its aspect ratio to make it more square if you're not planning to chop up a 210. The latter also gets rid of the standing waves between its parallel sides and can be configured to get the HF up to ~ear height. Anyway, my old rig used full size corner loaded 210 horns [reflex portion removed] with tweaked 511/802/500 Hz XO and preferred it over the previous 805/288B/500 Hz overall, so I see no reason why it won't do well with the 210/2 with a higher XO point as long as the distance between the drivers doesn't get acoustically too large.

GM