18sound in Horn 186

18lw1250

Fs 35 Hz
Re 5 Ohm
Sd 0,1134 sq.mt. (175,7 sq.in.)
Qms 8
Qes 0,28
Qts 0,27
Vas 268 lt. (9,47 cuft)
Mms 142 gr. (0,31 lb)
BL 23,6 Tm
Linear Mathematical Xmax (7) ± 9 mm (±0,35 in)
Le (1kHz) 2,73 mH
Ref. Efficiency 1W@1m (half space) 98 dB

pd186

Fs    27 Hz
Xmax    9 mm
Revc    5.5 Ohms
Vd    1.035 10-4 m3
Qts    0.312
No    2.05%
Qms    7.75
Pmx    700 Watts
Qes    0.326
Cms    188 µM/N
Vas    353 Litres
Mms    184 grams
Sd     1150 sq cm
BL    22.94 T/m

omegapro18

Resonant Frequency (fs)      25hz
DC Resistance (Re)            5.20
Coil Inductance (Le)           1.67mh
Mechanical Q (Qms)                  8.81
Electromagnetic Q (Qes)               0.32
Total Q (Qts)                            0.31
Compliance Equivalent Volume (Vas)        548.7 ltr/19.4 cu. ft.
Peak Diaphragm Displacement Volume (Vd)     556cc
Mechanical Compliance of Suspension (Cms)   0.29mm/N
BL Product (BL)                             18.8 T-M
Diaphragm Mass inc. Airload (Mms)            138 grams
Efficiency Bandwidth Product (EBP)           79
Maximum Linear Excursion (Xmax)              4.8
Surface Area of Cone (Sd)                    1159 cm2
Maximum Mechanical Limit (Xlim)             16mm




Qts and Vas determine box volume.

For the flattest frequency response in a closed box, Q = 0.7.
For less low extension and a boost in remaining low response, the box should be made smaller and Q > 0.7.
For a lower extension but a loss in existing low response, the box should be made larger an Q < 0.7.



for a sealed box a qts of 0.38 will require a box volume = Vas to produce a -3db low-cut at fs (theoretically). Q = 0.7

for a sealed box a qts of 0.2 will require a box volume well below Vas to produce a -3db low-cut well above fs. Q = 0.7

for a sealed box a qts of 0.5 will require a box volume well above Vas to produce a -3db low-cut well below fs. Q = 0.7

you can see that the 18sound has a lower Qts and a lower Vas than the 186. so it would prefer a smaller rear chamber.

the eminence has a similar qts (0.31:0.3) but has a much larger Vas (556:353) so would prefer a larger chamber. the eminence has a low fz but a weak xmax (cannot move much air) so is likely to have a worse bass response than the 186.

the 18sound would be better off in the 1850horn.
out of the two id go for the omega pro in the 186, unless you can affors the pd.

lower qts drivers have stronger motors and are in my opinion better.

The 18LW1400 has been used in the 186 horn to good effect.