The Smallest Tapped Horn

[MaVo]

Hi Patrick, you can make a TH with a mouthsize of about 1 * SD with good response. The simulation shows a Beyma 12P1000ND in a 60Liter tapped horn. Doubling the mouthsize gives you additional 3db maxspl.

[djk]

This is about an inch taller, and a couple of inches deeper. Kicks severe butt. A JBL2206 will also work in the same box.

[djk]

Mid-Bass / L12P540
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• high power 12" mid-bass
• very good power handling, excellent linearity and very low distortion
• diameter: 12"
• impedance: 8 Ù
• power: 400W rms, 800W program
• spl: 97 dB
• frequency range: 50 Hz–2 kHz
• voice coil: 3" copper
• baffle cutout: 11.2"
• depth: 6.1"
• weight: 18.7 lbs

[djk]

| 50 Hz Tapped Horn

Def_Const |Horn Dimensions

{
a1 = 150e-4; |Area at throat (cm^2)
a2 = 250e-4; |Area at rear of driver (cm^2)
a3 = 1100e-4; |Area at front of driver (cm^2)
a4 = 1200e-4; |Area at mouth (cm^2)
l1 = 15e-2; |Distance from throat to rear of driver (cm)
l2 = 178e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 25e-2; |Distance from front of driver to mouth (cm)
}

Def_Driver 'Dr1'

| RCF L12P540

Sd=530cm2
fs=59Hz
Qes=0.36
Qms=11
Vas=45L
Re=5.6ohm
Le=1.8mH

system 'S1'

Driver Def='Dr1' Node=1=0=3=4
Waveguide 'W1' Node=2=3 STh={a1} SMo={a2} Len={l1} Conical
Waveguide 'W2' Node=3=4 STh={a2} SMo={a3} Len={l2} Conical
Horn 'H1' Node=4 STh={a3} SMo={a4} Len={l3} Conical

[FlipC]

Still cant get my head around Hornresp.

Driver specs:
Power handling: 600 watts rms
Voice coil diameter: 2"
Voice coil inductance: 1.81 mH
Impedance: 4 ohm
DC resistance: 2.60 ohms
Frequency range: 20-450 Hz
Magnet weight: 112 oz.
Fs: 18.8 Hz
SPL: 90 dB 1W/1m, 93.4 dB @ 2.83V/1m
Vas: 232.2.
Qms: 8.66
Qes: .39
Qts: .38
Xmax: 15.1mm
Re: 2.8
Le: 1.82
Mms: 297.1
CMs: 0.24
Sd:829.6
Vd:1252.7
BL: 16

Trying to put this into a box of roughly 104.5 L

I don't understand how to get some of HRs measurements. Like Rms and Mmd. I also haven't figured out how to define box parameters. Layout equals a 13 foot horn length (roughly) within the space of 7 folds. 13 foot would (roughly) get me the 1/4 wave length for 50Hz ?


Help a laymen comprehend?

[djk]

"Trying to put this into a box of roughly 104.5 L"

The driver you listed is not suitable for a 50hz tapped horn.

"I don't understand how to get some of HRs measurements. Like Rms and Mmd. I also haven't figured out how to define box parameters. "

You don't have to understand them, just enter as required. The 'HELP' section tells you how to do this. The program calculates what it needs from common T/S parameters.

"Layout equals a 13 foot horn length (roughly) within the space of 7 folds. 13 foot would (roughly) get me the 1/4 wave length for 50Hz ?"

The speed of sound is roughly 1130 ft/sec, the 1/4W of 50hz is thus 5.65 ft, or 67.8 inches.

As you can see from my 50hz AkAbak script, the main horn length is 1.78m, or about 70 inches.

[Patrick Bateman]

As DJK alluded to, that's one of the great benefits of a tapped horn. It doesn't require a "typical" subwoofer driver, where the FS is very low, nor a "typical" horn driver, where QTS is very low.

[GM]

Originally posted by FlipC

Driver specs:

Trying to put this into a box of roughly 104.5 L

What make/model is this?

BTW, you didn't say what the XO point is, so don't know how much BW you want to try and get out of it.

As already noted, this is a very poor choice for a 50 Hz TH, especially in ~104.5 L due to its high Vas, but curiosity got the best of me to see how poor a choice it is:

GM

[Patrick Bateman]

After what I learned on my Tapped Horn for Dummies thread, I realized that the best driver for a 50hz horn would have an FS in the range of 60-100hz.

[djk]

Right you are.

RCF L12P540

Sd=530cm2
fs=59Hz
Qes=0.36
Qms=11
Vas=45L
Re=5.6ohm
Le=1.8mH