Building a 2000s cab

[melvinsfan]

Ok folks, since this place won't be operating forever I've got a few questions for those with more SUNN knowledge than I.

I'm thinking of building a 2x15 cab modeled after either a 200s or 2000s.  I'm leaning toward the 2000 because it's bigger and I really want to move some air.  I've looked on here for hours and can't find any dimensions.  There is a picture of one on Rich's site and the same picture in the schematics section on this site.  It just says rear loading folded horn but doesn't have any measurements.  I know the angles of the folded horn make a huge difference so I really need some exact numbers.

Is the earlier, horizontal horn cab louder or does it project more than the later cabs with the vertical horn on the right side?  I've always heard those early cabs were awesome but coming across one for a reasonable price is nigh on impossible.

[JoeArthur]

This is a link to an ebay auction for a 200s cab.  You might want to snatch the last two pictures as it shows a good view of the back and some of the construction details.

200s cab on ebay

If this was a true folded horn I would also be concerned about the angles.  It's actually more of a transmission line.  

I found this in the catalog section which gives the outside dimensions:



Not really a good picture.  From what seems to be the front opening of the port... it seems slightly smaller than the 4" of the JBL domes.

[melvinsfan]

If this was a true folded horn I would also be concerned about the angles.  It's actually more of a transmission line.  

What do you mean by this?
Are you saying that the angles don't make as much difference as I think?
I thought that angle of the horn and the size of the opening determine which frequency the horn enhances and how well it projects.

Any recommendations for wood type?  

Speaker type?  I'll try to get JBLs but am open to suggestions.

Has anyone here built a similar cab?

[JoeArthur]

What do you mean by this?
Are you saying that the angles don't make as much difference as I think?
I thought that angle of the horn and the size of the opening determine which frequency the horn enhances and how well it projects.

Think of what a horn enclosure is.  It starts off with a throat of a small cross-sectional area and then slowly (and somewhat exponentially) flares out to a large cross-sectional area.  It is this design or flaring that give the horn it's effeciency... because it acts much like a transformer or impedance conversion device between the speaker diaphram and the air.  Angles and the rate of expansion of the cross-sectional area is extremely important in horn design.

Now look at the design of the sunn cabinet.  Where is the flare?  There is none.  In fact the only flaring going on is completely backwards from the way that a horn would flare.  This is not because it is "folded" nor is it because it is "rear loaded".  It is because it is not a horn - and calling it one as Sunn did does not make it one.

Don't get me wrong... the design is ingenious and it works quite well.  It is kind of a composite between a transmission line and an untuned bass reflex.

So the angles do not really matter - at least not for sound.  If you looked at that inside picture on ebay, you'll notice that the brace for those inside flaring baffles is 90 degrees, making those baffles a 45 degree angle.  This would make production much easier.

You might also notice that the drawing doesn't show the bracing nor does it show the horizontal brace across the back.

[EdBass]

Ok folks, since this place won't be operating forever I've got a few questions for those with more SUNN knowledge than I.

I'm thinking of building a 2x15 cab modeled after either a 200s or 2000s.  I'm leaning toward the 2000 because it's bigger and I really want to move some air.  I've looked on here for hours and can't find any dimensions.  There is a picture of one on Rich's site and the same picture in the schematics section on this site.  It just says rear loading folded horn but doesn't have any measurements.  I know the angles of the folded horn make a huge difference so I really need some exact numbers.

Is the earlier, horizontal horn cab louder or does it project more than the later cabs with the vertical horn on the right side?  I've always heard those early cabs were awesome but coming across one for a reasonable price is nigh on impossible.

I have all of the cabinets you describe in your post. What measurement do you need? In the 2000S cabinet the angled port goes to within approx. 1"-1.5" of the back of the cabinet, and opens ultimately to a shared 4.5" port opening, gradually increasing in throat size via the deep center brace. The 200S is the same concept, but scaled down more or less proportionately.

I think that's why Mr. Sundholm used "horn" in his description.
Maybe or maybe not real scientific, maybe not a folded horn enclosure in the classic sense, but certainly tuned for a specific purpose none the less*.

If you build a 2000S, and if you plan to gig with it, be prepared for a workout ; they sound good, but weigh a freakin' ton! When I'm feeling froggy and playing outside or at a large venue, I'll schlep a pair of them and one of my 2000S heads to a gig. Not very defined or modern sounding, but...Very cool, very loud, very rock 'n' roll!

If you PM me your email address, I'll measure and photograph whatever you need, BUT I'm not sure exactly when I'll have a chance to unbutton all those screws, it may be after the sad, sad demise of this wonderful site.


*Of course I'm not a real audio engineer, I just play one on television.