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Old 27th November 2012, 01:25 AM   #1
RodK is offline RodK  Canada
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Default New cab build with Eminence Legend CB15-8

I am looking to build a more portable cabinet for my son . He has 2 peavey 410tvx's but wants something more portable for smaller venues.He uses a Peavey Nitrobass head and a Fender Deluxe Jazz 5 string.
I can get an Eminence Legend CB15-8 locally. would this be ok on it's own or does it need a mid? Also when I model it in winisd, I am exceeding xmax (6mm) from 55 to 90 hz in a 4 cu ft box tuned to 40 hz. how can I fix that. If it needs a mid, is the Eminence Alpha 8mra good to use? I can't figure out how to model the alpha to see what it adds. If I need the mid, do I have to use a crossover?

Any help would be greatly appreciated.

Last edited by RodK; 28th November 2012 at 01:50 AM.
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Old 5th December 2012, 08:20 PM   #2
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Look into some lightweight neodymium magnet bass speakers to put in a medium-size isobaric cabinet that's deep (ported or sealed). The result will be a very light and reasonably small cabinet that isn't very efficient but goes down as low as one twice its size. The small magnets allow you to mount isobaric drivers facing the same way close together without he need to clamshell. The big payoff is when you get to use a large cabinet and have it sound exactly like a huge one. Isobarics work for ported cabs too, I just prefer sealed. Just calculate like normal, then divide required box volume in half. It's only worth it when you save many liters of box volume. The big drawback is that it requires a lot of power, which won't be a problem. I hear Orange makes some nice isobaric bass guitar cabinets, you might try one and model from that if you like it.
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Old 5th December 2012, 08:59 PM   #3
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If he likes the sound of 8 10's, like an industry-standard SVT, decent low bass sometimes can NOT be had with fewer 10's, in which case the normal solution is to resort back to 12's or 15's. I assume that's why he's not toting just one 4X10? But a 15 bass speaker usually won't have the same treble. If you mix multiple sizes the common practice is to put them in seperate sealed boxes without any crossover, which also allows you more flexibility. Personally, I'd make a deep cabinet with 2 robust long-excursion 12's and two more hidden inside the box for isobaric magic. Your tastes may differ. Sorry I don't have experience with the specific Eminence models you mention. I guess I'm not much help. Go to a Guitar Center and try a dozen bottoms if it helps.
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Old 5th December 2012, 09:03 PM   #4
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Then again, if he likes the different character of the 15, it might be a good addition to his full rig of 10's when covering a large outdoor stage? I'm in favor of seperate boxes, you can always mix & match and find a use.
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Old 5th December 2012, 10:13 PM   #5
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Originally Posted by RodK View Post
when I model it in winisd, I am exceeding xmax (6mm) from 55 to 90 hz in a 4 cu ft box tuned to 40 hz. how can I fix that.
Turn the amp down or use more speakers.

It's simple physics - cone motion = SPL, with 4 times the cone motion required to go an octave lower. While it's true that you get some help from a horn, bass reflex, or transmission line cabinet, you said "portable".

BTW, the figure you want to be concerned with is Xlim, not Xmax. It's assumed a guitar speaker will exceed Xmax, which is a measure (wild guess) of the linear excursion of the speaker. MI speakers aren't linear - they need to compress near their limits to handle the poppin' an' slappin' of the strings.

So.... just how loud does this need to be? If we can give up SPLs, we can give up some size.

How low? Does his 5-string have a low B?

Take a look at this webpage for some ideas:
Art of Noise Audio - Home
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Old 6th December 2012, 01:28 AM   #6
JMFahey is offline JMFahey  Argentina
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Short answer, build it, he'll be happy.
2 things I *think* he must have clear by now, before actual construction:
1) 1 x15" is NOT the same as 4x10" , even less, 8x10" .
Yet it can save his bacon in many situations, where he does not need the full 8x10"
2) the response shown is still good, not muddy at all.
Only the presence peak shown , a very respectable 103dB, happens at 1800 Hz instead of the typical 2500Hz peak on 10" speakers.
Not bad , the cabinet will "snap" less but "growl" more , if those words mean something to you.
Killer Rock sound with a Precision, for example.
Meaning a less modern sound, more "70's/80's". Not bad, just a different sound.
And he also can mix and match, such as using a 15" cabinet + a 4x10", if situation allows it.
And the speaker is *inexpensive*.
If you build your own box, you'll have an interesting sound variation for peanuts.
Just do not subject it to crazy EQ or the latest madness: sub octavers .
At the beginning, play flat and raise the volume, so you have a *real* appreciation of what it can and what it can not do.
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Old 6th December 2012, 03:22 PM   #7
muzzer is offline muzzer  United Kingdom
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If you are interested in the Fearful bass cabinets, there is also a guy in Canada that builds/sells them here SHO Bass

I have just ordered a 12/6 in flat-pack form from a guy in the UK who makes them Speaker Builder

They use and Eminence Kappalite 3012LF as a bass driver, which has a huge Xmax and is very light (neo magnet), but is quite pricey for a bass/PA driver.
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