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Author Topic: First-Time Builder Seeks Feedback  (Read 7896 times)

rob barone

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First-Time Builder Seeks Feedback
« on: May 11, 2015, 11:50:14 am »

Hello & Thank You in advance - I'm a first-time sub builder hoping to find a little real-world advice.

I'd like to add a pair of compact, light subs to the line array tops we're using for live performance.  A pair of 4 x 6" w/ 6 tweeter array over a pair of 2 x 6" w/ 2 tweeters.  Speakers are Eminence Alpha 6.

The group is typical - guitar, bass, drums, sax, vocals (funk / soul).  The venues are small, 50 -100 ppl., & currently, we just mic vocals & sax.

The reading I've done so far, has led me to believe that a sealed cabinet is what I'm looking for.  Second to that, would be a ported design.  Given an Eminence-based design scheme, the two subs I've drawn up are based around a Kappalite 3012 LF 4 & a Delta 15 LF 4 - with the parameters provided by Eminence.

I've attached a simple sketch to help illustrate.

Thanks again.  Any advice / feedback is appreciated.

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Mac Kerr

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« Reply #1 on: May 11, 2015, 11:57:02 am »

Hello & Thank You in advance

Please go to your profile and change the "Name" field to your real first and last name as required by the posting rules displayed in the header at the top of the section, and in the Site Rules and Suggestions in the Forum Announcements section, and on the registration page when you registered.

Mac
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Art Welter

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Re: First-Time Builder Seeks Feedback
« Reply #2 on: May 11, 2015, 01:56:50 pm »

Hello & Thank You in advance - I'm a first-time sub builder hoping to find a little real-world advice.
The reading I've done so far, has led me to believe that a sealed cabinet is what I'm looking for.  Second to that, would be a ported design.  Given an Eminence-based design scheme, the two subs I've drawn up are based around a Kappalite 3012 LF 4 & a Delta 15 LF 4 - with the parameters provided by Eminence.

I've attached a simple sketch to help illustrate.

Thanks again.  Any advice / feedback is appreciated.


Eminence provides specifications for various alignments for their speakers:

http://www.eminence.com/pdf/Delta_15A_cab.pdf

As you can see, sealed  and small alignments give you the least LF output "bang for the buck".

Xmax (linear excursion) is the single most important parameter when designing a sub, as doubling Xmax allows for 6 dB more output. The Delta 15 LF is not really a "sub" driver, it has only 2.7mm Xmax, while Xmax for a decent 15" sub goes as much as 20mm, with 11-15mm fairly common.

A driver with 11mm could put out about 12 dB more than a 2.7mm driver, and would sound well over twice as loud. It would require 12 dB more power, but power is cheap and light compared to cabinets.

The Eminence Lab 12 has 13mm Xmax, it does well as a sub in relatively small enclosures, and the cabinet can be used to pole mount your columns.

Art
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rob barone

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Re: First-Time Builder Seeks Feedback
« Reply #3 on: May 12, 2015, 07:30:24 am »

Eminence provides specifications for various alignments for their speakers:

http://www.eminence.com/pdf/Delta_15A_cab.pdf

As you can see, sealed  and small alignments give you the least LF output "bang for the buck".

Xmax (linear excursion) is the single most important parameter when designing a sub, as doubling Xmax allows for 6 dB more output. The Delta 15 LF is not really a "sub" driver, it has only 2.7mm Xmax, while Xmax for a decent 15" sub goes as much as 20mm, with 11-15mm fairly common.

A driver with 11mm could put out about 12 dB more than a 2.7mm driver, and would sound well over twice as loud. It would require 12 dB more power, but power is cheap and light compared to cabinets.

The Eminence Lab 12 has 13mm Xmax, it does well as a sub in relatively small enclosures, and the cabinet can be used to pole mount your columns.

Art

Thank you Art - I see what you mean.  I think my interest in a sealed design led me to consider the Delta.  Am I off-track to pursue a sealed design, believing it will be the most focused & require the least EQ at each new venue? 

I've noticed the Lab 12, but have been put off by it's 25#.  Would you consider the Kappalite LF4 a suitable driver to base a small sub around?  Eminence lists a ported enclosure of 2.478 cu ft as an option.

Fs 37.02
Qts .32
Vas 3.77 cu ft
xmax 9.1 mm

Cheers - Rob
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Art Welter

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Re: First-Time Builder Seeks Feedback
« Reply #4 on: May 12, 2015, 01:48:29 pm »

1)Am I off-track to pursue a sealed design, believing it will be the most focused & require the least EQ at each new venue? 

2)I've noticed the Lab 12, but have been put off by it's 25#.  Would you consider the Kappalite LF4 a suitable driver to base a small sub around?  Eminence lists a ported enclosure of 2.478 cu ft as an option.

Fs 37.02
Qts .32
Vas 3.77 cu ft
xmax 9.1 mm
Rob,

1)A sealed enclosure in general rolls off at 12 dB per octave, a ported at 24 dB per octave, but can be flatter down to Fb than a sealed box, so EQ is not really a consideration. For live use, where you want the maximum impact for size and weight, ported or tapped horns are far more effective than sealed. Although I use sealed subs in my home stereo, I wouldn't consider them for live use.

2) The specs look more like a sub, though 9.1mm is still on the low side of current offerings from other companies. If you choose to go as small as 2.478 cu ft, LF output will be pretty limited.

When it comes to subs, Hoffman's Iron Law rules:
Loud, low, or small-pick any two.

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rob barone

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Re: First-Time Builder Seeks Feedback
« Reply #5 on: May 12, 2015, 03:07:43 pm »

Thanks Art.  I suppose if I had to pick 2, it would be small & low.  I don't know how loud we really need to be for 100 ppl... 'til now, we've gotten by with just the vox & sax mic'd up. 

Do you know of Bill Fitzmaurice designs?  I believe they are horn subs. 

If you were looking for a sub to fill this need, what would you use?

Again, thank you
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Spenser Hamilton

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Re: First-Time Builder Seeks Feedback
« Reply #6 on: May 12, 2015, 03:58:21 pm »

Do you know of Bill Fitzmaurice designs?  I believe they are horn subs. 

I wouldn't waste my time/money.
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Technical Director - Chatham Capitol Theatre/Kiwanis Theatre

rob barone

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Re: First-Time Builder Seeks Feedback
« Reply #7 on: May 12, 2015, 07:08:07 pm »

Spencer -  certainly no equivocation there... do you have any recommendations as to which type of sub would work best for my situation?  Thanks
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Spenser Hamilton

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Re: First-Time Builder Seeks Feedback
« Reply #8 on: May 12, 2015, 09:00:38 pm »

Spencer -  certainly no equivocation there... do you have any recommendations as to which type of sub would work best for my situation?  Thanks

I'll second Art's recommendation of the Lab 12 in a small bass reflex, the best part being that the design and testing has already been done (again, you can thank Art for that).

https://soundforums.net/threads/134-FREE-SUB-PLAN-Dual-Lab12-(Front-Loaded)-by-Welter-Systems

I built a few Tuba 30's loaded with Lab 12s, not a terrible box but definitely not worth the investment of time and sweat required to bang out a few, they fall wayyy short of the hype. I stuck the drivers in a cab based on Art's design, and then soon after ordered 6 more drivers to make additional subs, you can see all of my progress in the linked thread.

Some thoughts
 - Good response down low, stand-up bass... just WOW.
 - Not the loudest sub, but a pair driven off of an iTech 6000 were cruising along for a jazz gig in front of approx 120 people. 4 cabs driven off the same amp were okay for doing metal bands in front of approx 200-250 kids, I'm talking half stacks and gorilla drummers using bright cymbals (think AAX Xplosion type stuff).
 - The build is very straight-forward, the angles on the port wall are 45'. Construction cost is fairly low.
 - I can lift a cab by myself (28 years old, 5'11, 270lbs), very easy to move with a partner.
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Richard Turner

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Re: First-Time Builder Seeks Feedback
« Reply #9 on: May 12, 2015, 10:25:25 pm »

first off read the threads in the sub forum I commented on about the futility of homebrew subs in this day and age

But seeing as you are likely dedicated to the project having already built some homebrew sideways clonearray cabs here goes

http://www.eminence.com/pdf/Delta_15LFA_cab.pdf

or use #6 from this page
http://www.jblpro.com/pub/manuals/enclgde.pdf

You can have a good cabinet or a light cab you pick. Best build would be with 3/4" void free baltic birch ply, thinner requires more bracing as power handling and SPL increase.


for hardware google

penn-elcom
transcanad hardware
diyroadcases.com

but seriously read the thread from this winter and do the total cost of the project vs purchasing.

Other worthy boxes that can be salvaged and repurposed are the behringer 1800bx, peavey subcompact 18 and many others that are ok cabinete that can shine with a driver upgrade
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Looking at retiring. Local PA market has shrank to 2 guys with guitars and bose l1 compacts or expecting full line array and 16 movers on stage for $300... no middle left going back to event DJ stuff, half the work for twice the pay.

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Re: First-Time Builder Seeks Feedback
« Reply #9 on: May 12, 2015, 10:25:25 pm »


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