Wolverine LS-8 Cabinet?

[jallenbass]

I modeled a couple of cabinet designs in WinISD and wasn't too pleased with the results. Any good ideas? BIBs maybe? I have some T/S parameters if that helps.

[GM]

Due to its high Qts, it's best suited for either OB or aperiodic loading. Here's a max flat impedance ~aperiodic end loaded TL:

L = 45.5"
WxD = ~202.5"^2

All dims i.d. and the sim reflects a 1.2 lbs/ft^3 polyfil stuffing density:

GM

[jallenbass]

Thanks GM. I'm new to speaker building. Given the specs how do I figure out the dimensions? What might be the best way to design the aperiodic port?

[GM]

You're welcome!

Think of a transmission line (TL) as a vented box where the vent was sized so large that the box/vent system morphed into one large, long tube, so the 'vent' area = WxD area and can either be in the form of an open bottom with the TL spaced up off the floor or one big cutout on one of its sides or its area divided up into smaller slots on more than one side. Since it's end loaded, the driver will be at the extreme top front.

Since wider baffles are typically better performing overall and since there will be considerable stuffing to smooth it out there's no need to worry about any strong internal standing waves (eigenmodes) to reflect back through the driver, so you can either make it a visually pleasing ratio or as narrow/wide as the driver dims allows. IOW choose one dimension and divide it into 202.5"^2 to find the other one, rounding them up to the next convenient fraction if required.

To make it ~aperiodic (damp its resonant pipe modes), we stuff it with some type of absorbent material till it sounds as good as you can get it with the understanding that it may take considerable experimentation to find the right material and/or amount (density) of stuffing to find an acceptable balance between it sounding too under-damped (resonant) Vs too over-damped ('dead').

GM

[kvk]

Do you know what the aperiodic dims would be for an LT-12?

[jallenbass]

OK. Feel free to point me to further reading if these questions are too elementary.

So I can build a cabinet with inside dimensions of (HxWxD) 45.5x22.5x9. Correct? What size would the port be or is it just an open bottom that is elevated off of the floor? If the latter is the case then I could vary the elevation to vary the resistance of the port.

Thanks so very much for your patience.

[GM]

Don't have specs for the LT-12, only LS-12........

GM

[GM]

Originally posted by jallenbass

So I can build a cabinet with inside dimensions of (HxWxD) 45.5x22.5x9. Correct?

What size would the port be or is it just an open bottom that is elevated off of the floor?

You're welcome!

Correct.

Right, previously: "......so the 'vent' area = WxD area and can either be in the form of an open bottom with the TL spaced up off the floor or one big cutout on one of its sides or its area divided up into smaller slots on more than one side."

So if in the bottom front or back, then the cutout would be 9" high if full width.

FWIW, I calc ~4.93" = no resistance for bottom firing.

GM

[jallenbass]

Great. I have 2 more questions. How critical is the speaker position on the front baffle? I know that it needs to be pretty high. Can it be offset slightly to the left or right? And just to double check my math what we have is a 5.33 cubic ft cabinet so it needs about 6.33 lbs of fill?

[kvk]

Originally posted by GM
Don't have specs for the LT-12, only LS-12........

GM

THe LT12 and LS12 are pretty close. Here's some parms---

From--
http://db.audioasylum.com/cgi/m.mpl...light=wolverine
Revc = 5.3515 ohms
Fs = 59.1659 Hz
Zmax = 18.0568 ohms
Qes = 1.6780
Qms = 3.9838
Qts = 1.1807
Le = 0.2776 mH (at 1 kHz)
Diam = 259.0800 mm ( 10.2000 in )
ConeArea =52717.8422 mm^2( 81.7128 in^2)
Vas = 99.8152 L ( 3.5249 ft^3)
BL = 5.7921 N/A
Mms = 28.2967 g
Cms = 255.7180 uM/N
Kms = 3910.5574 N/M
Rms = 2.6405 R mechanical
Efficiency = 1.1877 %
Sensitivity= 92.7470 dB @1W/1m
Sensitivity= 94.4931 dB @2.83Vrms/1m

From—
http://db.audioasylum.com/cgi/m.mpl...light=wolverine
[EV - LT12 sample #1]
Fs = 57.000 Hz
Zmax = 38.153 ohms
Re = 5.330 ohms
Zdb3 = 15.224
F1 = 52.771 Hz
F2 = 64.874 Hz
Qms = 13.452
Qes = 1.879
Qts = 1.649
Le = 0.0873 mH
Sd = 591.023 sq.cm
Cms = 0.2356 mm/N
Mms = 0.03309 kg
BL = 5.797 Tm
n0 = 1.10577 %
Vas = 116.397 liters
SPL = 92.455 dBSPL 1W/1M
[EV - LT12 sample #2]
Fs = 60.000 Hz
Zmax = 26.155 ohms
Re = 5.830 ohms
Zdb3 = 13.655
F1 = 54.653 Hz
F2 = 72.865 Hz
Qms = 7.717
Qes = 1.720
Qts = 1.407
Le = 0.1396 mH
Sd = 591.023 sq.cm
Cms = 0.2736 mm/N
Mms = 0.02571 kg
BL = 5.732 Tm
n0 = 1.63633 %
Vas = 135.172 liters
SPL = 94.157

From— http://www.geocities.com/tadgesuald...parameters.html
LS12 (LS12 is similar to LT12)
Fs: 58.35
Re:6.746
Qms: 7.722
Qes: 2.217
Qts: 1.722
Cms: 0.342 mm/N
Mms: 21.74g
Sd: 557 sq. cm
Le: 0.2 mH
BL: 4.925 N/A
Vas 151 liters
1w SPL: 95dbs

Fs of three different LS12's
Fs A: 58
Fs B: 47
Fs C: 60