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Old 27th March 2008, 03:44 AM   #1
CarlosT is offline CarlosT  United States
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Default Build A Bandpass Box Around This...

...going back to my earlier thread on the Kohler commercial...

Eminence KAPPALITE 3015LF

Nominal Basket Diameter 15", 381mm
Nominal Impedance* 8 ohms
Power Rating Watts 450W Music/Program 900W
Resonance 42Hz
Usable Frequency Range 40Hz-1.5kHz
Sensitivity*** 99.8
Magnet Weight 11 oz.
Gap Height 0.365", 9.27mm
Voice Coil Diameter 3", 76.2mm

THIELE & SMALL PARAMETERS
Resonant Frequency (fs) 42Hz
DC Resistance (Re) 5.31
Coil Inductance (Le) 0.92mH
Mechanical Q (Qms) 6.82
Electromagnetic Q (Qes) 0.41
Total Q (Qts) 0.39
Compliance Equivalent Volume (Vas) 158.8 liters / 5.6 cu.ft.
Peak Diaphragm Displacement Volume (Vd) 846cc
Mechanical Compliance of Suspension (Cms) 0.14mm/N
BL Product (BL) 18.6 T-M
Diaphram Mass inc. Airload (Mms) 101 grams
Efficiency Bandwidth Product (EBP) 102
Maximum Linear Excursion (Xmax) 9.6mm
Surface Area of Cone (Sd) 881.1 cm2
Maximum Mechanical Limit (Xlim) 17.0mm


You guys think this is a good candidate for a 4th order bandpass box? I'm thinking DJ application...
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Old 27th March 2008, 12:01 PM   #2
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Simulates quite nice - sealed chamber 100 L, vented 50 L tuned to 70 Hz. Bandwith 41 Hz to 119 Hz, calculated SPL 123 dB/m at 450 W. Xmax is exceeded at 43 Hz.

But 150 L vented cab tuned to 40 Hz goes down to about 35 Hz and no excursion problems to 32 Hz. SPL is about the same.
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Old 27th March 2008, 05:41 PM   #3
CarlosT is offline CarlosT  United States
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Thanks...that's kinda a big box...innit?
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Old 27th March 2008, 05:48 PM   #4
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For a 15" driver it's not that big at all. In fact there are not many PA 15-inchers that require 100 L or less, and they're more like midbass in 2-way speakers (though personally I don't like anything bigger than 10" above 1 kHz, but that's another story )
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Old 1st April 2008, 03:34 PM   #5
palesha is offline palesha  India
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For bandpass box accuracy of thiel-small parameters play very important part.
If ur speaker & thielsmall parameters on which u rely hv more difference, then u will not get the sound u expect.
Better check thielsmall parameters accurately, then design the box.
It will give u better results.
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Old 2nd April 2008, 11:46 PM   #6
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A good quality 15" 4 ohm car sub may play some thunderous lows.
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Old 3rd April 2008, 06:15 AM   #7
palesha is offline palesha  India
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Quote:
You guys think this is a good candidate for a 4th order bandpass box? I'm thinking DJ application...
For DJ application better use HD 15 cabinet or use scoop design by eminance. In short, u need horn speaker cabinet.

The .Qts is not suitable for bandpass for dj use
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Old 3rd April 2008, 11:26 AM   #8
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For DJ applications forget car subs - they are of low sensitivity and are meant to play in a really small room.

For generic DJ application I would also forget HD15-s that are meant to work in large groups of at least 4 and need separate subbass cabs below (something like X1) for anything else than hardcore techno. And I would leave scoops, that are big, heavy and a bit outdated design, to reagge sound systems

Bandbass is good but not the ideal, too - complicate to build and integrate with smaller tops that don't like being pushed down to 100 Hz and lower.

Reflex is the most versatile thing - can be integrated with wide variety of tops, are scalabele (bring one for house party, bring 8 to outdoor live band), easy to build and easy to get right.
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Old 3rd April 2008, 08:39 PM   #9
palesha is offline palesha  India
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Normally DJ's prefer hard rib breaking bass.
I don't think that vented box will give that kind of sound pressure.
If still want to use vented, then minimum two drivers in parallel will be required in one box.
There by spl will be increased by 3 db.
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Old 3rd April 2008, 09:31 PM   #10
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A well designed double-15" (or 18") reflex has sensitivity around 100 dB/W/m, gives you ~130 dB at one meter, and probably go lower than a horn of similar size.

As for doubles, they are IMO worth using only if you do push-pull configuration to lower distortion. On the other hand, lots of people don't like like this low distortion sound - that doesn't sound so loud as moderately distorted bass from conventional boxes. If you do not use push-pull, two singles are the same SPL-wise, easier to carry and more scaleable.

I would suggest reading this before deciding, very good information on differences between horns and reflex.
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