Hello,
Going in Akabak into a little more depth and reading chapter
Radiation-Elements you could see;
"The mutual coupling between different radiators is not supported directly and must be modeled explicitly"
If you want to integrate the mutual coupling, which is certainly the case with a tapped horn, you should read the chapters Feedback and Potentials. This is though part for me and don`t get it figured in the script.
This mutual coupling basically means you want to use the pressure (as function of time/phase) in the horn as a spring (compliance) for you radiators. If you get this right, it think you should see the real goal of the tapped horn: reduction in cone excursion, maybe a efficiency change.
Is there anybody who can figure something out with the feedback approach?
Cheers,
Marcel
Going in Akabak into a little more depth and reading chapter
Radiation-Elements you could see;
"The mutual coupling between different radiators is not supported directly and must be modeled explicitly"
If you want to integrate the mutual coupling, which is certainly the case with a tapped horn, you should read the chapters Feedback and Potentials. This is though part for me and don`t get it figured in the script.
This mutual coupling basically means you want to use the pressure (as function of time/phase) in the horn as a spring (compliance) for you radiators. If you get this right, it think you should see the real goal of the tapped horn: reduction in cone excursion, maybe a efficiency change.
Is there anybody who can figure something out with the feedback approach?
Cheers,
Marcel
Compact woofer for DJ use, 10mm x-max.
| 40 Hz Tapped Horn
Def_Const |Horn Dimensions
{
a1 = 500e-4; |Area at throat (cm^2)
a2 = 881e-4; |Area at rear of driver (cm^2)
a3 = 3100e-4; |Area at front of driver (cm^2)
a4 = 3200e-4; |Area at mouth (cm^2)
l1 = 20e-2; |Distance from throat to rear of driver (cm)
l2 = 250e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 10e-2; |Distance from front of driver to mouth (cm)
}
Def_Driver 'Dr1'
| Eminence 3015LF
Sd=881cm2
fs=42Hz
Qes=0.41
Qms=6.82
Vas=160L
Re=5.31ohm
Le=0.92mH
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
| 40 Hz Tapped Horn
Def_Const |Horn Dimensions
{
a1 = 500e-4; |Area at throat (cm^2)
a2 = 881e-4; |Area at rear of driver (cm^2)
a3 = 3100e-4; |Area at front of driver (cm^2)
a4 = 3200e-4; |Area at mouth (cm^2)
l1 = 20e-2; |Distance from throat to rear of driver (cm)
l2 = 250e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 10e-2; |Distance from front of driver to mouth (cm)
}
Def_Driver 'Dr1'
| Eminence 3015LF
Sd=881cm2
fs=42Hz
Qes=0.41
Qms=6.82
Vas=160L
Re=5.31ohm
Le=0.92mH
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
If I´m not mistaken, this resulst in a very big Box (more than 400 Liters). Since the SPL is not much higher than in a Standard-Reflex enclosure and cutoff is about 35Hz, the benefit over a reflex-enclosure with 150 Liters seems to be minimal. Or am I missing something?
if that's half-space then seems pretty loud at 40
http://img244.imageshack.us/img244/9456/djk3015lfjn0.gif
made a sketch?
http://img244.imageshack.us/img244/9456/djk3015lfjn0.gif
made a sketch?
"I get 99dB at 40Hz with 2.83V"
Did you change from 4Pi to 2Pi?
This driver may not benefit as much as others from the tapped horn. I selected it because of its light weight and low price. Two of the same drivers in a reflex box of the same bulk give similar output (ignoring the cost of the extra driver), but won't be 3dB down at 35hz.
The Kilomax Pro15A looks like it's also 102dB at 40hz, and still goes to 35hz. While it's 16lbs heavier, and costs $60 more, it may have 3dB more maximum output than the 3015LF (due to its higher power rating).
The Difinimax 4015LF looks virtually identical to the Kilomax Pro15A.
Fred: How do you export the images? I tried to copy them to Word (like I did with Bass Box), but it doesn't seem to work.
Did you change from 4Pi to 2Pi?
This driver may not benefit as much as others from the tapped horn. I selected it because of its light weight and low price. Two of the same drivers in a reflex box of the same bulk give similar output (ignoring the cost of the extra driver), but won't be 3dB down at 35hz.
The Kilomax Pro15A looks like it's also 102dB at 40hz, and still goes to 35hz. While it's 16lbs heavier, and costs $60 more, it may have 3dB more maximum output than the 3015LF (due to its higher power rating).
The Difinimax 4015LF looks virtually identical to the Kilomax Pro15A.
Fred: How do you export the images? I tried to copy them to Word (like I did with Bass Box), but it doesn't seem to work.
Screenshots: Look at "edit" -> "Copy as bitmap"
@djk
The mentioned Eminence Subs all have suboptimal TSP for a tapped Horn. Try calculating the size of your resulting Horn, its very huge.
I was looking for a lightweight, compact Horn too, where 50Hz f3 is enough (small Setups with little tops). I looked for drivers with a high fs, found none at Eminence, so i took a look at Monacor
Should be around 130Liters, gives 98dB/2.83V/m with 50Hz f3, Neodym driver. I didn´t try the 15s from monacor so far.
| 50 Hz Tapped Horn with SP-10A/250NEO
Def_Const |Horn Dimensions
{
a1 = 215e-4; |Area at throat (cm^2)
a2 = 220e-4; |Area at rear of driver (cm^2)
a3 = 1170e-4; |Area at front of driver (cm^2)
a4 = 1178e-4; |Area at mouth (cm^2)
l1 = 38e-2; |Distance from throat to rear of driver (cm)
l2 = 150e-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'
| SP-10A/250NEO
Sd=347cm2
fs=80Hz
Qes=0.66
Qms=16.76
Vas=19L
Re=5.7ohm
Le=0.3mH
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
@djk
The mentioned Eminence Subs all have suboptimal TSP for a tapped Horn. Try calculating the size of your resulting Horn, its very huge.
I was looking for a lightweight, compact Horn too, where 50Hz f3 is enough (small Setups with little tops). I looked for drivers with a high fs, found none at Eminence, so i took a look at Monacor
Should be around 130Liters, gives 98dB/2.83V/m with 50Hz f3, Neodym driver. I didn´t try the 15s from monacor so far.
| 50 Hz Tapped Horn with SP-10A/250NEO
Def_Const |Horn Dimensions
{
a1 = 215e-4; |Area at throat (cm^2)
a2 = 220e-4; |Area at rear of driver (cm^2)
a3 = 1170e-4; |Area at front of driver (cm^2)
a4 = 1178e-4; |Area at mouth (cm^2)
l1 = 38e-2; |Distance from throat to rear of driver (cm)
l2 = 150e-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'
| SP-10A/250NEO
Sd=347cm2
fs=80Hz
Qes=0.66
Qms=16.76
Vas=19L
Re=5.7ohm
Le=0.3mH
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
No, didn´t change anything. I wasn´t aware that we´re modelling free space. Did I miss something, I thought every sim we do here is half-space? Mybe I forgott something all the time so far, please help me out. What ist the default space Akabak uses when started up with defaults? (Would be great, becuase then alle my previous models would actually be much louder than assumed, since I always thought them to be half-space. If theyre actually freespace, it´s even better 🙂 )
Here's a fun little horn for the Aussie builders out there using the Jaycar Venom 12" 25-100Hz total volume 250L. Should do 115dB @ 25Hz with 200W of drive:
| 25 to 100 Hz Jaycar "Venom 12" Tapped Horn
Def_Const |Horn Dimensions
{
a1 = 315e-4; |Line area at throat (cm^2)
a2 = 320e-4; |Line area at rear of driver (cm^2)
a3 = 800e-4; |Line area at front of driver (cm^2)
a4 = 900e-4; |Line area at mouth (cm^2)
l1 = 30e-2; |Distance from throat to rear of driver (cm)
l2 = 300e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 70e-2; |Distance from front of driver to mouth (cm)
}
Def_Driver 'Dr1'
| Venom12
Sd=450cm2
fs=31Hz
Qes=0.558
Qms=7.698
Vas=69.49L
Re=3.5ohm
Le=3mH
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
| 25 to 100 Hz Jaycar "Venom 12" Tapped Horn
Def_Const |Horn Dimensions
{
a1 = 315e-4; |Line area at throat (cm^2)
a2 = 320e-4; |Line area at rear of driver (cm^2)
a3 = 800e-4; |Line area at front of driver (cm^2)
a4 = 900e-4; |Line area at mouth (cm^2)
l1 = 30e-2; |Distance from throat to rear of driver (cm)
l2 = 300e-2; |Line distance from rear of driver to front of driver (cm)
l3 = 70e-2; |Distance from front of driver to mouth (cm)
}
Def_Driver 'Dr1'
| Venom12
Sd=450cm2
fs=31Hz
Qes=0.558
Qms=7.698
Vas=69.49L
Re=3.5ohm
Le=3mH
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
"Try calculating the size of your resulting Horn, its very huge. "
About 10% more total bulk than the Danley TH115, which is OK for my use (mine being the same size as the Cerwin Vega SL-36).
My design is 103dB at 40hz vs yours being 86dB, the extra half octave of bass extension being needed in dance music. Mine peaks at 40hz vs the Danley at 45hz.
About 10% more total bulk than the Danley TH115, which is OK for my use (mine being the same size as the Cerwin Vega SL-36).
My design is 103dB at 40hz vs yours being 86dB, the extra half octave of bass extension being needed in dance music. Mine peaks at 40hz vs the Danley at 45hz.
Maybe I set something wrong in Abakab (freespace vs halfspace). Could you clarify on the issue? Does Abakab calculate free space per default? How do I switch to half-space. And while I´m asking: Do you have any info if excursion ist represented as peak-peak or like in speaker-spec-sheets "+-" wise?
Default in AkAbak is 4Pi.
Change it to 2Pi when you run 'sum'.
Save the script, and the next time you make changes and sim it, it will be in 2Pi.
New designs are always default mode.
"Do you have any info if excursion ist represented as peak-peak or like in speaker-spec-sheets "+-" wise?"
I'm not sure. I posted my scrips less than a half hour after I loaded the program, and I haven't read the 285 page manual (yet).
Change it to 2Pi when you run 'sum'.
Save the script, and the next time you make changes and sim it, it will be in 2Pi.
New designs are always default mode.
"Do you have any info if excursion ist represented as peak-peak or like in speaker-spec-sheets "+-" wise?"
I'm not sure. I posted my scrips less than a half hour after I loaded the program, and I haven't read the 285 page manual (yet).
Ok, changed to Halfspace. I end ab with about 100db@40Hz.
@freddi
What did you do to come up with ~103dB@40Hz?
@freddi
What did you do to come up with ~103dB@40Hz?
hi Dennis - regarding images, I do a screen shot, then edit-paste-crop wih an old horrible Dell program - then "copy and paste" that result into Windows Paint where it can be crudely labled - then save as gif.
on your 40Hz horn's script, IIRC theres 10cm from driver to mouth - got any sketch yet? - how does mouth aspect affect response and overtones if mouth area is fixed?
on your 40Hz horn's script, IIRC theres 10cm from driver to mouth - got any sketch yet? - how does mouth aspect affect response and overtones if mouth area is fixed?
Hello Freddy,
You could see the boundery conditions in my text-file. You should put in a reflector , the groundplane.
I included a simulation file of a tapped horn with the 15TBX100 of B&C. I have given the driver a compression ratio of 1:2.5, so far it think it should be safe for the cone.
Check out the excursiondiagram for a 4-pack. You could driven this pack with 78V RMS without exceeding xmax.
Give this 4-pack a input voltage of 14.1V RMS(each box given 25W of input power) at 10mtr and you have the equal of 1W/1Mtr, resulting in 109dB from 40hz up.
It`s possible to choose a somewhat higher cutt-of frequency and allowing you to drive the 4-pack with a full 90V RMS.
Def_Driver 'TBX100'
SD=855cm2 |Piston
fs=35Hz Mms=163g Rms=6.893Ns/m
Bl=25.5Tm Re=5.1ohm Le=1.6mH ExpoLe=0.8
Def_Reflector Wall=25cm
HAngle=0 VAngle=-90
System 'S1'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=342.5cm2 SMo=2400cm2
Vf=5L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=2400cm2 SMo=2650cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=55cm HEdge=1.14m reflection
System 'S2'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Driver 'D2' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=685cm2 SMo=4800cm2
Vf=10L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=4800cm2 SMo=5300cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=120cm HEdge=1.14m reflection
System 'S3'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Driver 'D2' Def='tbx100' Node=1=0=20=21
Driver 'D3' Def='tbx100' Node=1=0=20=21
Driver 'D4' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=1370cm2 SMo=9600cm2
Vf=20L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=9600cm2 SMo=1.06m2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
dEdge=2.28m Reflection
Cheers,
Marcel
You could see the boundery conditions in my text-file. You should put in a reflector , the groundplane.
I included a simulation file of a tapped horn with the 15TBX100 of B&C. I have given the driver a compression ratio of 1:2.5, so far it think it should be safe for the cone.
Check out the excursiondiagram for a 4-pack. You could driven this pack with 78V RMS without exceeding xmax.
Give this 4-pack a input voltage of 14.1V RMS(each box given 25W of input power) at 10mtr and you have the equal of 1W/1Mtr, resulting in 109dB from 40hz up.
It`s possible to choose a somewhat higher cutt-of frequency and allowing you to drive the 4-pack with a full 90V RMS.
Def_Driver 'TBX100'
SD=855cm2 |Piston
fs=35Hz Mms=163g Rms=6.893Ns/m
Bl=25.5Tm Re=5.1ohm Le=1.6mH ExpoLe=0.8
Def_Reflector Wall=25cm
HAngle=0 VAngle=-90
System 'S1'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=342.5cm2 SMo=2400cm2
Vf=5L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=2400cm2 SMo=2650cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=55cm HEdge=1.14m reflection
System 'S2'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Driver 'D2' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=685cm2 SMo=4800cm2
Vf=10L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=4800cm2 SMo=5300cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=120cm HEdge=1.14m reflection
System 'S3'
Driver 'D1' Def='tbx100' Node=1=0=20=21
Driver 'D2' Def='tbx100' Node=1=0=20=21
Driver 'D3' Def='tbx100' Node=1=0=20=21
Driver 'D4' Def='tbx100' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=1370cm2 SMo=9600cm2
Vf=20L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=9600cm2 SMo=1.06m2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
dEdge=2.28m Reflection
Cheers,
Marcel
hi Marcel - that's quite a woofer -but a bit large for a living room :^)
B&C 15trx40 and PZB40 don't make much impact in small bass reflex having aobut 3dB loss @100Hz vs a lighter cone 15"
http://img319.imageshack.us/img319/2342/vm151vsbcgp7ku.jpg
Best,
Freddy
B&C 15trx40 and PZB40 don't make much impact in small bass reflex having aobut 3dB loss @100Hz vs a lighter cone 15"
http://img319.imageshack.us/img319/2342/vm151vsbcgp7ku.jpg
Best,
Freddy
http://i56.photobucket.com/albums/g196/dkleitsch/TBX100x1.jpg
One TBX100 driver.
http://i56.photobucket.com/albums/g196/dkleitsch/3015LFx4.jpg
Four 3015LF
Def_Driver '3015LF'
Sd=881cm2
fs=42Hz
Qes=0.41
Qms=6.82
Vas=160L
Re=5.31ohm
Le=0.92mH
Def_Reflector Wall=25cm
HAngle=0 VAngle=-90
System 'S1'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=500cm2 SMo=2400cm2
Vf=10L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=2400cm2 SMo=2650cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=55cm HEdge=1.14m reflection
System 'S2'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Driver 'D2' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=1000cm2 SMo=4800cm2
Vf=20L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=4800cm2 SMo=5300cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=120cm HEdge=1.14m reflection
System 'S3'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Driver 'D2' Def='3015LF' Node=1=0=20=21
Driver 'D3' Def='3015LF' Node=1=0=20=21
Driver 'D4' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=2000cm2 SMo=9600cm2
Vf=40L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=9600cm2 SMo=1.06m2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
dEdge=2.28m Reflection
One TBX100 driver.
http://i56.photobucket.com/albums/g196/dkleitsch/3015LFx4.jpg
Four 3015LF
Def_Driver '3015LF'
Sd=881cm2
fs=42Hz
Qes=0.41
Qms=6.82
Vas=160L
Re=5.31ohm
Le=0.92mH
Def_Reflector Wall=25cm
HAngle=0 VAngle=-90
System 'S1'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=500cm2 SMo=2400cm2
Vf=10L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=2400cm2 SMo=2650cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=55cm HEdge=1.14m reflection
System 'S2'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Driver 'D2' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=1000cm2 SMo=4800cm2
Vf=20L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=4800cm2 SMo=5300cm2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
WEdge=120cm HEdge=1.14m reflection
System 'S3'
Driver 'D1' Def='3015LF' Node=1=0=20=21
Driver 'D2' Def='3015LF' Node=1=0=20=21
Driver 'D3' Def='3015LF' Node=1=0=20=21
Driver 'D4' Def='3015LF' Node=1=0=20=21
Waveguide 'W1' Node=20=21
STh=2000cm2 SMo=9600cm2
Vf=40L Len=2.55m T=0.9
Horn 'W2' Node=21
STh=9600cm2 SMo=1.06m2
Len=25cm Conical
x=0 y=0 z=0 HAngle=0 VAngle=0
dEdge=2.28m Reflection