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Double Bass Loudspeaker recommendations for DIY sealed DB cabinet

#21
Matthijs said:
I used the fdeck design as a starting point for my own 12/6 design using the deltalite 2512 II and can highly recommend it. It allowed me to build a small and lightweight cab with the low end power handling and efficiency of a ported cab and the low freq gradual drop off of a sealed cab.

The top end of the deltalite is a bit spikey, but imho not unpleasant. That probably highly depends on how the speaker combines with your bass, pickup and amp. I had more concerns with the bump over 2k and went for a flatter response and less beaming with a 6".
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Which midrange driver did you use?
 
#22
JohnOH said:
I am amazed at how helpful you guys are. I've now got more options and more to think about. In particular, I realise that the fundamental below about 80Hz on a DB is only subtle and so a gentle rolloff from there down should sound natural. That allows me to consider a wider range of drivers, focusing more on what the rest of the range sounds like. Thanks to everyone.
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When I first purchased Duke's Audiokinesis TC-112 I had lots of reservations about rear ported cabinets. At the time, I felt that front ports were better suited to DB, especially in smaller rooms where there was less room
to set a rear ported cabinet the appropriate distance from the wall. I was also convinced that one had to have a low end that extended down toward at least 50 Hz. The TC-112's allayed all my reservations. So I applaud
you for trying to come up with a small 15" sealed box, but there are IMHO better options. Mike Arnopol's Crazy 8' also comes to mind as well as his new 2X6. Good luck with your project, I hope it does the job for you.

Ric
 
#24
fdeck said:
I am presently leaning towards side porting -- basically to put the port on the smallest face, which corresponds to having more internal space to make it longer.
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Francis,
Euphonic Audio did that with their Wizzy M Line 12's from all indications, that's a very successful compact little box with excellent low end response. They also did that with the CM 208 that they never brought into production.Unfortunately, even with a pre order offer from EA they couldn't get 50 players to commit to a order. I think the side port has real merit.

wizzym.jpg
CM208-1.jpg
 
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#26
Ric Vice said:
When I first purchased Duke's Audiokinesis TC-112 I had lots of reservations about rear ported cabinets. At the time, I felt that front ports were better suited to DB, especially in smaller rooms where there was less room
to set a rear ported cabinet the appropriate distance from the wall. I was also convinced that one had to have a low end that extended down toward at least 50 Hz. The TC-112's allayed all my reservations.
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Thank you, Ric. The rear ports on the TC1-112 are diagonally centered behind the woofer in an attempt to a) provide a symmetrical airload on the back of the cone (I can explain why if anyone's interested) and b) provide a bit of chimney-effect cooling. Credit to Jerry McNutt of Eminence (who designed the Kappalites and most of their other woofers) for this configuration.

fdeck said:
I am presently leaning towards side porting -- basically to put the port on the smallest face, which corresponds to having more internal space to make it longer.
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Yes, shoe-horning an adequate port into a small cab can be a challenge! Sometimes flared ports can help, as you can get away with a bit smaller diameter (and therefore a bit less length) before chuffing sets in, but then you have to deal with the width of that inner flare.

The place where chuffing tends to set in is at the inner end of the port. It's a fluid-flow problem. With a straight-sided port the flat baffle area around the outer (flush-mounted) end assists airflow into the port, acting as a crude funnel, but the free-hanging inner end has no such funnel... until we put a flare on it. The "poor man's flare" is to cut the inner end of the port on a 45 degree angle, and the resulting elliptical opening has increased cross-sectional area and therefore a bit higher chuffing threshold. Credit to Earl Geddes for this idea. Also, with the angled cut, you don't have to deal with the width of an inner flare.

If you ever decide to try running a port vertical, the outer flare gives you a smooth enough transition that you can get away with 1" tall feet on a 3" diameter port and not have any "choke points" like you would with a straight-sided port. Not so good for playing on grass or sand or a thick shag carpet, but should work fine just about anywhere else. And the effective port length is increased, so it's almost a free lunch, if greater port length is what you need.

The flared ports I like best are "Precision Ports". The midrange energy that escapes through them isn't diffracted by a sharp edge, so it can be a small net benefit. And their inner diameters are what they say they are (which isn't always the case), so an expandable plumber's test plug fits, enabling you to change tunings (if you have multiple ports) or convert to a low-Q sealed box.

Ric Vice said:
They also did that with the CM 208 that they never brought into production.Unfortunately, even with a pre order offer from EA they couldn't get 50 players to commit to a order. I think the side port has real merit.View attachment 513485
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What can you tell me about the CM 208? Did you get to try one? I found this information on Google, does it sound right to you?

"400W, 2-8 in. proprietary speakers with a 1 in. phenolic compression driver, 8 ohm impedance, two Speakon combo connectors, black covering, black metal grille, side handles, 16 in. wide, 19.5 in. tall, 12.75 in. deep, 41 lbs."
 
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#27
The EA CM208, as I understand it, was supposed to be an updated version of the EA VL208. It used two 8-inch drivers with an HF horn (w/ compression driver) in an M-Line transmission line design (similar to that used in the EA Wizzy M). It was never released as a part of the EA product line.
 
#28
robgrow said:
The EA CM208, as I understand it, was supposed to be an updated version of the EA VL208. It used two 8-inch drivers with an HF horn (w/ compression driver) in an M-Line transmission line design (similar to that used in the EA Wizzy M). It was never released as a part of the EA product line.
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Thank you. That would have been a very interesting cab. There are things you can do with two woofers, each at a different place along a transmission line's path, that can offer a bit of improvement over a comparable single-woofer line.
 
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#29
I designed my cabs with a vertical shelf port at the back that almost covers the whole back.

One reason for putting the port on the back was my idea that you'd probably won't hear to much of the chuffing if the port is on the back. I never really tested if that's true. So far I didn't hear any chuffing, I don't think that's hard evidence though.
 
#30
robgrow said:
I have an OEM version of the Eminence C2515 in a less-than-optimum size enclosure. (I had both of these laying around, so I thought I'd give them a try.) WinISD did not predict good results, but to my surprise, I love the sound of this combination. This cab is strong in the 40 to 50 Hz range without over emphasizing this range, and will even reproduce 30Hz. An open E is very satisfying while not boomy. But it's the balance I really like. The DB has a lot going on in the low mids, and the C2515 reproduces this range very well. The high mids are also extended, and I don't feel the need for a tweeter. I just happen to like full-range drivers, and woofers (drivers designed to reproduce primarily LF) usually don't sound quite right to me for DB and BG. Good luck with your project.
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what do ya'llz mean by double bass?
thanx p
 
#31
In my experience of 27 years of trying to find the right setup for double bass, I have ended up with Greenboy's Fearless F112 and Fearful 12/6 at the top of my list. I built a 12/6, sold it, had instant seller remorse, and have built another. Compact, light, will soak up 900-1000 watts, uncoloured, they will have to prise this one from my cold, lifeless fingers. Cost me about NZ$1000 to build, about AU$880 or US$660.
 

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