Sunn Musical Equipment > DIY

Help with 1x15 build

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AEA:
hey guys,

I have been interested in building a lightweight 1x15 reflex cab similar to a half sunn 200s cab modified to use bracing and 1/2" ply. Now these cabs have a port that becomes angled 45 degrees about halfway in.

How does this affect the tuning of the cab?

What program can I use for optimising the design for use with either a 3015 or 15pr400? Will any include this style of design?



Any other advice for designing this style of cab is more than welcome!
 

Walt-Dogg:

--- Quote from: AEA on September 12, 2015, 11:51:53 am ---hey guys,

I have been interested in building a lightweight 1x15 reflex cab similar to a half sunn 200s cab modified to use bracing and 1/2" ply. Now these cabs have a port that becomes angled 45 degrees about halfway in.

How does this affect the tuning of the cab?

What program can I use for optimising the design for use with either a 3015 or 15pr400? Will any include this style of design?



Any other advice for designing this style of cab is more than welcome!

--- End quote ---
Sounds similar to the 1x15(X) or 1x18(X) so me.I've always wanted a pair of JBL loaded 15s or Vega loaded 18s.

You'll want to design the box around speaker in something like WinISD, you can set up the encloser like the sunn but use the software to tune the angle and depth of the vent/port and overall dimension of the cab.

EdBass:
It's just a folded configuration of a ducted port. I believe Conrad Sundholm said the design came to him in a dream, and referred to the design as a a "folded horn port". Works for me, can't argue with the man who designed it, and there is NO question the design works fantastically in a bass guitar application.

That cab was designed in an era that predates the modern freeware that makes anyone with a PC an "acoustical engineer".
WinISD is released as freeware and suddenly every enthusiast forum on the planet is filled with self proclaimed "internet experts" on MI cab design, blathering on about what can't sound good, and how MI amp rigs should be designed.
Here's an example; spec (and WinISD) wise the SVT 810 is horrible as a full range cab, high mid heavy with bass response that falls off a table at around 100hz. For some reason bass players who can have anything they want still use them on big league pro stages all over the world.
I guess these pro players and sound engineers don't know that they are so terrible, and that a passively crossed over bass cab with a compression driver is a much better choice. I guess they don't pay much attention to internet forum speaker gurus...
 
I think you would find it difficult or even impossible to accurately emulate the response characteristics of the 200S cab in freeware like WinISD, you would need something more sophisticated (as in expensive), and have the training to use it.

Not that all of this really matters, for a couple of reasons;

MI cabs are different than SR cabs, their design spec isn't to as efficiently and accurately reproduce the designated range of the driver they are designed to enclose. They are designed to sound good amplifying the instrument they are meant to be used for, which is usually a much less exacting task. MI cabs primarily are sound/tone producers rather than the program sound reproducers that SR cabs are.

But more importantly, if you are looking for the best enclosure for a specific Eminence or Faital driver, ask Eminence or Faital rather than try to adapt or modify a design that was meant for a JBL D140F in the mid 60's. Seriously, the driver manufacturers know what parameters work for ANY specific application for the drivers they produce, and it's not a secret; they will tell you what these parameters are and point you in the right direction.

Sorry about the little rant, but try contacting the manufacturer(s) of the drivers in question. No one will have more insight/experience/expertise into making their drivers work well than they do!

Soundmasterg:
You may find some inspiration from post # 29 and #42 in this thread >> http://sunnforum.ampage.org/index.php/topic,10005.28.html where I show the 1x15 cabinet I made. When upright it has the same width as a 200S head and when on its side it is the same width as a 2000S head. It is also as deep as a 2000S cabinet front to back. The port is at the bottom and is half as tall as the full size 2x15 200S cabinet to keep the frequency response the same. I used a JBL E140 in the cabinet and later added some 6 inch tweeters, and it is internally braced. The back lower area of the cabinet is made like a modern Ampeg SVT cabinet with the angle and casters mounted there. The cabinet is using 3/4" plywood, which I suggest as even with bracing the 1/2" will likely flap around more than you would like. I also highly suggest to put stuff in the cabinet to dampen the reflections like foam or similar. I also highly suggest to front mount the speaker. If you want take a look at the pics I posted on the thread above.

I agree with Ed about going to the manufacturer's page to get the specs and you can try to use those programs to design a cabinet that will work for a given speaker, but keep in mind those programs usually assume a round port and not a full width Sunn style port. The cabinet that I made sounds fantastic and very similar to a 200S cabinet with slightly different bass response due to the different speaker.

Greg

AEA:
Thanks. This is all contrary to the advice I have gotten from other forums.
I have had most people tell me to go and use a fearful design. Either that or I was told the angled port will have no affect on the response of the cab and to use something from wines.

Really liking the 200s and 2000s I really would rather had down that route so I'm glad to have been given some great advice and positive feedback.

I have heard a 2000s with the 15pr400 and it sounded great. They have the d140 vibe and so that's why I was interested in using them. My main concern with halving the port size was whether there would be some interaction between 2 speakers using the port together. So it's as simple as halving the port?

My plan is to build one cab then if it is what I'm hoping for building a second for a stack.

Greg how much bracing did you use in your cab? How heavy did yours turn out?

Cheers again guys!

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