Akabak for beginers

Visc=... (Optional) Reflex enclosure. Factor to switch off calculation of vent-damping due to
viscosity or to modify its strength.
Off: Visc = 0
Default: Visc = 1
Decrease of damping: Visc = 0 ... 1
Increase of damping: Visc > 1

There are referances all the way through the manuel on visc if you do a key word search on the manuel it will highlight them all for you.

ok i have been trying to script the single usb and the single hd15, see plots below....



the usb script is....

Def_Driver 'Driver'

SD=1188.0cm2
fs=32Hz
Mms=211g
Qms=10.38
Qes=0.36
Re=6.19ohm
Vas=237.9L
Bl=27.0Tm
Cms=0.12mm/N
Le=4.78mH
ExpolE=1

System 'System'

Driver Def='Driver''Driver'
Node=0=1=2=3

Enclosure 'Rear chamber'
Node=2
Vb=68.2L

Duct 'Throat chamber'
Node=3=4
SD=1188.00cm2
Len=14.85cm
Visc=0

Waveguide 'Horn segment 1'
Node=4=5
STh=830.76cm2
SMo=980.4cm2
Len=10.0cm
Conical

Waveguide 'Horn segment 2'
Node=5=6
STh=980.4cm2
SMo=1145.52cm2
Len=10.0cm
Conical

Waveguide 'Horn segment 3'
Node=6=7
STh=1145.52cm2
SMo=1460.28cm2
Len=10.0cm
Conical

Waveguide 'Horn segment 4'
Node=7=8
STh=1460.28cm2
SMo=1991.76cm2
Len=10.00cm
Conical

Waveguide 'Horn segment 5'
Node=8=9
STh=1991.76cm2
SMo=2507.76cm2
Len=10.0cm
Conical

Waveguide 'Horn segment 6'
Node=9=10
STh=2507.76cm2
SMo=2796.72cm2
Len=5.3cm
Conical

Radiator 'Horn mouth'
Node=10
SD=2796.72cm2

and the hd15 script is......

Def_Driver 'Driver'

SD=856.3cm2
fs=35Hz
Mms=102g
Qms=7.3
Qes=0.32
Re=6.5ohm
Vas=198.8L
Bl=21.6Tm
Cms=1.53E-04m/N
Le=1.40mH
ExpolE=1

System 'System'

Driver Def='Driver''Driver'
Node=1=0=2=3

Enclosure 'Rear chamber'
Node=2
Vb=51L
Sb=855.00cm2


Duct 'Throat chamber'
Node=3=4
SD=1982.40cm2
Len=10.08cm
Visc=0

Waveguide 'Horn segment 1'
Node=4=5
STh=544.80cm2
SMo=722.16cm2
Len=27.38cm
Conical

Waveguide 'Horn segment 2'
Node=5=6
STh=722.16cm2
SMo=1054.92cm2
Len=15.25cm
Conical

Waveguide 'Horn segment 3'
Node=6=7
STh=1054.92cm2
SMo=1785.57cm2
Len=15.36cm
Conical

Waveguide 'Horn segment 4'
Node=7=8
STh=1785.57cm2
SMo=2206.16cm2
Len=8.97cm
Conical

Radiator 'Horn mouth'
Node=8
SD=2206.16cm2



but im not happy with the results any ideas guys...

may be....vtc isn't correct....try to add the cone volume 4500e-6 for 15", 6500e-6 for 18" I think. Define the section by rectangular areas I mean hth wth etc...


Anyone can sim on akabak at 4pi? The coupler function is useful for more than one cab...but at 2pi.

As I understand it, if you specify baffle height and width in the "Radiator" section, Akabak starts modelling an enclosure in 4pi with baffle-step[1]. Then you can use "Reflector" to add reflecting boundaries such as the floor.

[1] Baffle-step is a big deal. It can tilt your response by 3dB/octave and drop the sensitivity of drivers by up to 6dB compared to the half-space sensitivity usually quoted on data sheets. For some driver/baffle combinations, it can even add a 3-6dB peak!

Thanks JSG, so let me says what I get from your post.
Describe radiator dimension and distance between the floor defining y value on radiator elements, am I right?

Just another issue....
I'm trying to sim more than one cab stacked...so I take the jsg mighty dubpass script with the coupler...but if I set the num variable to 1 I'm expeting to have the same response without the coupler....but it's so different at all.

Ok im trying to sim the martin 215mk3 but not very well......... any ideas where im going wrong......

|COMMENT: martin 215mk3 pd1550

Def_Driver 'Bassdriver1'

SD=890cm2
fs=31Hz
Mms=123.4g
Qms=5.55
Qes=0.22
Re=6.4ohm
Vas=242L
Bl=26.34Tm

Def_Driver 'Bassdriver2'

SD=890cm2
fs=31Hz
Mms=123.4g
Qms=5.55
Qes=0.22
Re=6.4ohm
Vas=242L
Bl=26.34Tm

System 'System'

Driver Def='Bassdriver1''Driver 1'
Node=1=0=5=6

Duct 'Rear chamber'
Node=4=5
SD=5.56cm2
Len=23cm
Visc=0

Duct 'Throat chamber'
Node=6=12
SD=1660.00cm2
Len=3.61cm
Visc=0


Driver Def='Bassdriver2''Driver 2'
Node=1=0=10=11

Duct 'Rear chamber'
Node=9=10
SD=5.56cm2
Len=23cm
Visc=0

Duct 'Throat chamber'
Node=11=12
SD=1660.00cm2
Len=3.61cm
Visc=0

Waveguide 'Horn segment 1'
Node=12=13
STh=640.00cm2
SMo=1372.00cm2
Len=50.00cm
Conical

Waveguide 'Horn segment 2'
Node=13=14
STh=1372.00cm2
SMo=1960.00cm2
Len=29.50cm
Conical

Waveguide 'Horn segment 3'
Node=14=15
STh=1960.00cm2
SMo=3150.00cm2
Len=28.00cm
Conical

Waveguide 'Horn segment 4'
Node=15=16
STh=3150.00cm2
SMo=4876.00cm2
Len=24.00cm
Conical

Radiator 'Horn mouth'
Node=16
SD=4876.00cm2

God im starting to hate akabak...... lol.....

im having problems trying to sim a 6th order sript is below........
cant work out where im going wrong any ideas.............

Def_Driver 'Driver'

FS=32Hz
Re=5.3ohm
Qes=0.32
Qms=5.6
Vas=187dm3
Sd=1210cm2
Mms=275g
Bl=30.30Tm
Le=1.90mH
Cms=8.96E-05m/N
Rms=9.91Ns/m
ExpoLe=1

System 'System'

Driver Def='Driver''Driver'
Node=1=0=5=6

Radiator 'Port outlet'
Node=3
SD=684.00cm2
Label=1

Duct 'Port'
Node=3=4
SD=684.00cm2
Len=26.00cm
Visc=0

Duct 'Rear chamber'
Node=4=5
SD=1.23cm2
Len=50.40cm
Visc=0

Duct 'Throat chamber'
Node=6=8
SD=2520.00cm2
Len=75.0cm
Visc=0

Duct 'Horn segment 1'
Node=8=9
SD=684.00cm2
Len=43.50cm
Visc=0

Radiator 'Horn mouth'
Node=9
SD=684.00cm2
Label=2

am i making a skool boy error or is this the wrong way to sim it........ smiley33

easy: I think it's 1230cm2 and not 1.23cm2 which is really too small, so:

Duct 'Rear chamber'
Node=4=5
SD=1230cm2
Len=50.40cm
Visc=0

skool boy error lol...... been going over it for an hour...... not sure how i missed it lol cheers m8t.