freddi said:
If you make a new script, the only thing written in it is
System 'S1'
I forgot to mention, you have to copy my script and paste it <<after>> the words System 'S1' in the new script. If you delete those words or paste my script before them, it wont work.
You could also change the frequency values in the F5 menu to something like 10-500 to skip the not so interesting high frequencies.
thanks - that does look interesting - how do you think it compares to the other models?
http://img66.imageshack.us/img66/6193/thwg1ok3.gif
http://img66.imageshack.us/img66/6193/thwg1ok3.gif
Well I will have to say the sound quality at the moment varies with spl and frequency, as I didn't brace the cab internaly as agressively as I should have but the spl performance should be close to what was graphed but it buzzes in some spots.
As far as, My listening and measuring seem to confirm that there is a bit more 2nd harmonic distortion (subjectively not objectionable sounding) around 20dB down, 3rd Harmonic distortion apears to be stupid low I think I measured something like 40 or 50dB down.
It definately sounds the best between 21-60Hz. The prototype makes a little noise in the 60-70Hz range which is due to lack of bracing. Its hard for me to judge the full qualilty of the sound as It is currently in a warehouse full of tools and shelves of things that rattle and buzz. And the little blue sky moitor speakers that I have are up stairs in a loft to monitor some of my source material.
From up there the quality of the LF is pretty nice, I can feel every LF tone through the loft, and most of the buzzning and rattling can't be heard.
From my own observation, I think my BS-212's that I built (A pair of 12cu' cabs housing 2 lab 12's each mounted push pull) Have much lower 2nd harmonic distortion, which makes some of the 20-30Hz tones seem more transparent. And I can get more clean SPL out of them at 20Hz (until vent velocity gets to high) than I can out of this TH prototype.
Mind you the pair of BS-212's can't do what the TH can do SPL wise from 22Hz on up without at least 2kW. The TH has an 800watt driver in it now.
Also I think my sealed quad lab 12 sub did pretty good down to and bellow 20Hz with lots of EQ, quite a lot of impact but can't compete with either the BS-212 or TH for SPL until about 50Hz.
I won't give a conclusion on over all sound quality until I get it well alligned and balanced with some full range boxes. Listening to the sub by it self doesn't really give any clear indication of SQ other than I didn't brace it good enough. Though I probably wouldn't ever need to use it that loud in a home environment so its not a total loss as a prototype.
I susspect that people will find it more "Musical" than a speaker with less 2nd harmonic distortion, and It does hit pretty hard probably due to the boost in sensitivity in the 70's.
I'm excited I have enough head room available that I can develop some sort of equal loudness curve EQ for the bottom end.
I like it, I think it would be great in almost any audio application that the space is available in.
Though my experience in small houses with lots of sub bass is, dishes rattling and studs vibrating apear louder than some of the low fundamental tones that are causing the disturbance.
Anyhow-
I give it thumbs up. I just want to push that knee down a bit more. I like to hit my 20 with authority.
Antone-
As far as, My listening and measuring seem to confirm that there is a bit more 2nd harmonic distortion (subjectively not objectionable sounding) around 20dB down, 3rd Harmonic distortion apears to be stupid low I think I measured something like 40 or 50dB down.
It definately sounds the best between 21-60Hz. The prototype makes a little noise in the 60-70Hz range which is due to lack of bracing. Its hard for me to judge the full qualilty of the sound as It is currently in a warehouse full of tools and shelves of things that rattle and buzz. And the little blue sky moitor speakers that I have are up stairs in a loft to monitor some of my source material.
From up there the quality of the LF is pretty nice, I can feel every LF tone through the loft, and most of the buzzning and rattling can't be heard.
From my own observation, I think my BS-212's that I built (A pair of 12cu' cabs housing 2 lab 12's each mounted push pull) Have much lower 2nd harmonic distortion, which makes some of the 20-30Hz tones seem more transparent. And I can get more clean SPL out of them at 20Hz (until vent velocity gets to high) than I can out of this TH prototype.
Mind you the pair of BS-212's can't do what the TH can do SPL wise from 22Hz on up without at least 2kW. The TH has an 800watt driver in it now.
Also I think my sealed quad lab 12 sub did pretty good down to and bellow 20Hz with lots of EQ, quite a lot of impact but can't compete with either the BS-212 or TH for SPL until about 50Hz.
I won't give a conclusion on over all sound quality until I get it well alligned and balanced with some full range boxes. Listening to the sub by it self doesn't really give any clear indication of SQ other than I didn't brace it good enough. Though I probably wouldn't ever need to use it that loud in a home environment so its not a total loss as a prototype.
I susspect that people will find it more "Musical" than a speaker with less 2nd harmonic distortion, and It does hit pretty hard probably due to the boost in sensitivity in the 70's.
I'm excited I have enough head room available that I can develop some sort of equal loudness curve EQ for the bottom end.
I like it, I think it would be great in almost any audio application that the space is available in.
Though my experience in small houses with lots of sub bass is, dishes rattling and studs vibrating apear louder than some of the low fundamental tones that are causing the disturbance.
Anyhow-
I give it thumbs up. I just want to push that knee down a bit more. I like to hit my 20 with authority.
Antone-
hi Antone - was the high H2 due to the driver? what power levels produced that high of 2nd harmonic? That might make it too "phat" -- H2 30 or more dB down would be much better.
(btw -MaVo's LAB12 TH script with DIYMA12 looks poor - I'd like to see his schematic vs enclosure sketch for the simplified script)
DIYMA in same enclouse - I think
http://img47.imageshack.us/img47/5025/thwg1diyma12kq7.gif
Freddy
(btw -MaVo's LAB12 TH script with DIYMA12 looks poor - I'd like to see his schematic vs enclosure sketch for the simplified script)
DIYMA in same enclouse - I think
http://img47.imageshack.us/img47/5025/thwg1diyma12kq7.gif
Freddy
yeah - that's a bit optimistic too.
ya know, regarding high H2, can't find graph yet, but according to an old post my 11.2 cubic foot Yorkville UCS1 pipehorn at 20vrms & 50Hz had 10dB higher H2 than a 103g mms Eminence 18" with qt=0.26 in an 8 cubic foot Karlson box. AT 50Hz the K had a bit more ouput for same voltage drive. (UCS1's input Z was higher)
at 34Hz and small signal neither box is usable--the pipehorn had 15dB higher H3. It sounds "phat" and I won't use it. A vented box could be cleaner at home levels. Edgar's monolith with Dayton 295-070 is fairly clean to its nominal 40Hz cutoff. The Karlson seems to damp cone motion.
did you measure H2 outdoors?
Freddy
ya know, regarding high H2, can't find graph yet, but according to an old post my 11.2 cubic foot Yorkville UCS1 pipehorn at 20vrms & 50Hz had 10dB higher H2 than a 103g mms Eminence 18" with qt=0.26 in an 8 cubic foot Karlson box. AT 50Hz the K had a bit more ouput for same voltage drive. (UCS1's input Z was higher)
at 34Hz and small signal neither box is usable--the pipehorn had 15dB higher H3. It sounds "phat" and I won't use it. A vented box could be cleaner at home levels. Edgar's monolith with Dayton 295-070 is fairly clean to its nominal 40Hz cutoff. The Karlson seems to damp cone motion.
did you measure H2 outdoors?
Freddy
I included two 90 degree bends in the model and cleared it up a bit. To use it, copy it in an new akabak script after the System 'S1' line. Since the manual isnt very usefull concerning the accoustic mass, i am rather guessing what could be right. But then again, changing the acoustic mass only changes the high frequency response shape and the overall efficiency of the box. The model represents the geometry of the TH made by for example William Cowan. Tapping the driver into the horn is not supported (for this, use my first model posted some pages earlier)
You can play with the input data in Def_Const or the Def_Driver data.
Def_Driver 'Lab12'
dD=25.2cm |Piston
fs=33Hz Mms=146g Qms=13.32
Bl=15Tm Re=4.29ohm Le=1.48mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 26e-2; | The outer driver diameter
Hornlength = 400e-2; | The overall length of the horn including the ducts around the driver
Box_z = 32e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 10e-2; | Throat Area = Box_z * Throat_x
Mouth_x = 30e-2; | Mouth Area = Box_z * Mouth_x
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='Lab12'
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}
You can play with the input data in Def_Const or the Def_Driver data.
Def_Driver 'Lab12'
dD=25.2cm |Piston
fs=33Hz Mms=146g Qms=13.32
Bl=15Tm Re=4.29ohm Le=1.48mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 26e-2; | The outer driver diameter
Hornlength = 400e-2; | The overall length of the horn including the ducts around the driver
Box_z = 32e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 10e-2; | Throat Area = Box_z * Throat_x
Mouth_x = 30e-2; | Mouth Area = Box_z * Mouth_x
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='Lab12'
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}
re: new model - maybe Cowan would run a mathcad to compare and help pick how much complexity on akabak is really needed to do 20-200Hz?
re: distortion - found the graph - ucs1 pipehorn had >20dB worse H2 than my smaller and lighther karlson with 18" at 20vrms/50Hz
20vrms-50Hz commercial pipehorn vs Karlson
http://img80.imageshack.us/img80/8623/ucs1vsk1820v50yg5.jpg
would the waveguide model work for these mutual load cases?
re: distortion - found the graph - ucs1 pipehorn had >20dB worse H2 than my smaller and lighther karlson with 18" at 20vrms/50Hz
20vrms-50Hz commercial pipehorn vs Karlson
http://img80.imageshack.us/img80/8623/ucs1vsk1820v50yg5.jpg
would the waveguide model work for these mutual load cases?
An externally hosted image should be here but it was not working when we last tested it.
"would the waveguide model work for these mutual load cases?"
Sure. Check the AbAbak manual on page 65 and following. There is a great example how to simulate a bandpass box. You can see how to translate a box into akabak models. Your pictures contain some ducts for the rear volume, an accoustic mass for the 90 degree bend, waveguides for the expanding structure and a radiator.
Cowans 30hz horn with the 830500 driver:
http://img260.imageshack.us/img260/7550/830500ft6.jpg
What do you think about the accuracy?
Sure. Check the AbAbak manual on page 65 and following. There is a great example how to simulate a bandpass box. You can see how to translate a box into akabak models. Your pictures contain some ducts for the rear volume, an accoustic mass for the 90 degree bend, waveguides for the expanding structure and a radiator.
Cowans 30hz horn with the 830500 driver:
http://img260.imageshack.us/img260/7550/830500ft6.jpg
What do you think about the accuracy?
G'day MaVo
You've done a great job with your tapped horn model in AkAbak. The results appear to be close to my measurements, which were done with the mic in the center of the mouth. The Mathcad model was difficult to use and didn't offer anything that your model doesn't. The ability to include path length between the driver and mouth is very useful and should be included in your model. It is one of the variables one can use to fine tune a tapped horn.
I am starting to doubt the 830515 measurements I made. They were made quickly one evening and never repeated. I always thought the 830515 should work better in a 30Hz tapped horn than a 830500. I was very surprised when my measurements showed me this was not the case. Your model shows the 830515 to be a better performer and that matches my gut instinct a bit better.
Keep up the good work.
William Cowan
You've done a great job with your tapped horn model in AkAbak. The results appear to be close to my measurements, which were done with the mic in the center of the mouth. The Mathcad model was difficult to use and didn't offer anything that your model doesn't. The ability to include path length between the driver and mouth is very useful and should be included in your model. It is one of the variables one can use to fine tune a tapped horn.
I am starting to doubt the 830515 measurements I made. They were made quickly one evening and never repeated. I always thought the 830515 should work better in a 30Hz tapped horn than a 830500. I was very surprised when my measurements showed me this was not the case. Your model shows the 830515 to be a better performer and that matches my gut instinct a bit better.
Keep up the good work.
William Cowan
Hey Freddi,
I just revisited my THD sweeps and I'm actually Better than 30-40dB down for the 2nd Harmonic (measured at mouth unclear what power level is I didn't check) I would like to take more accurate measures outdoors soon.
I'm around 70dB down for 3rd Harmonic distortion which is RETARDED LOW !!!!!
I will have to post my dimensions so we can try and see if response I got can on my proto type final can be recreated in aKaBak.
Antone-
I just revisited my THD sweeps and I'm actually Better than 30-40dB down for the 2nd Harmonic (measured at mouth unclear what power level is I didn't check) I would like to take more accurate measures outdoors soon.
I'm around 70dB down for 3rd Harmonic distortion which is RETARDED LOW !!!!!
I will have to post my dimensions so we can try and see if response I got can on my proto type final can be recreated in aKaBak.
Antone-
MaVo said:
Using your model, here's the response of Cowan's 30hz tapped horn with an MCM 55-2421 woofer. The sensitivity is poor, but for $25, the response goes VERY low.
I'm going to reduce the size and see if I can bump the efficiency.
http://www.spicealley.net/~johnv/trash/55-2421-in-30hz-horn.jpg
Patrick, you may want to re evaluate your driver sensitivity, you didn't adjust your input voltage.
.707 Volts is not 1 watt unless your runing some really funny low impedance. And change the view window.
Its about 2.8V for 1W @ 8Ohms and about 2V for 1 Watt at 4Ohms.
But also you need to take a look at your Xmax numbers, around rated power.
Antone-
.707 Volts is not 1 watt unless your runing some really funny low impedance. And change the view window.
Its about 2.8V for 1W @ 8Ohms and about 2V for 1 Watt at 4Ohms.
But also you need to take a look at your Xmax numbers, around rated power.
Antone-
Tapped Horn For Dummies (part 1 of 3)
I have an idea -
What if I post a "tapped horn for dummies?"
This would be a tapped horn that ANYONE with a $40 circular saw can build... In fact you could probably build it with a handsaw!
In order to make it super-simple to build, I'm going to make it out of sonotube. Sonotube is cheap, easy to work with, and rigid. To make it dead-simple to build, I'm NOT going to taper the horn. So it's going to be a simple resonant pipe. Picture a sonotube with a divider down the center, and you have the general idea.
In order to make it accessible, I'm going to use my favorite cheap sub driver, the MCM 55-2421. For $25, there's no better sub driver.
First things first though...
Tom Danley often uses two subwoofers in his designs, and models them as a SINGLE sub. For example, the lab sub uses two twelve inch woofers. I'm going to do the same with my "tapped horn for dummies." I am going to use a PAIR of eight inch woofers.
Why two you ask?
By using two woofers, we double our power handling, and halve xmax for the same volume as a single eight. Can't beat that right?
But we have to figure out the parameters for a pair of drivers, instead of one.
Luckily I have a spreadsheet that does this. This spreadsheet allows you to model one, two, even four woofers as a single unit. It takes care of all the parameters for you (BL, VAS, SD, etc...)
Here it is:
www.spicealley.net/~johnv/diyaudio/050107/ts.xls
I have an idea -
What if I post a "tapped horn for dummies?"
This would be a tapped horn that ANYONE with a $40 circular saw can build... In fact you could probably build it with a handsaw!
In order to make it super-simple to build, I'm going to make it out of sonotube. Sonotube is cheap, easy to work with, and rigid. To make it dead-simple to build, I'm NOT going to taper the horn. So it's going to be a simple resonant pipe. Picture a sonotube with a divider down the center, and you have the general idea.
In order to make it accessible, I'm going to use my favorite cheap sub driver, the MCM 55-2421. For $25, there's no better sub driver.
First things first though...
Tom Danley often uses two subwoofers in his designs, and models them as a SINGLE sub. For example, the lab sub uses two twelve inch woofers. I'm going to do the same with my "tapped horn for dummies." I am going to use a PAIR of eight inch woofers.
Why two you ask?
By using two woofers, we double our power handling, and halve xmax for the same volume as a single eight. Can't beat that right?
But we have to figure out the parameters for a pair of drivers, instead of one.
Luckily I have a spreadsheet that does this. This spreadsheet allows you to model one, two, even four woofers as a single unit. It takes care of all the parameters for you (BL, VAS, SD, etc...)
Here it is:
www.spicealley.net/~johnv/diyaudio/050107/ts.xls
"what about the simplified model with only a few lines of script?
Freddy"
i made the sim with the following script. I figured the variables out of William Cowans schematic of the 30hz horn. When calculating the length of the horn, only take into account the straight parts without the bend, since the acoustic mass i used in the script should handle it. Thats why the length is 330cm.
I included the parameters for one of the "tapped horn for dummies" drivers for Patrick Bateman. It shouldnt be too complicated to simulate the horn with two drivers. For this i can again point to the manual on page 65 and following where a box with two drivers is simulated, taking into account the physical distance between the drivers, which could be more accurate than changing the TS parameters and handle it as a single one.
Def_Driver '830500'
dD=26cm |Piston
fs=18.1Hz Mms=166.3g Qms=3.7
Bl=17.6Tm Re=3.5ohm Le=4.2mH ExpoLe=0.618
Def_Driver '55-2421'
dD=26cm |Piston
fs=29.1Hz Mms=59.78g Qms=14
Bl=12.99Tm Re=3.4ohm Le=2.47mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 26e-2; | The outer driver diameter
Hornlength = 330e-2; | The length of the horn including the ducts around the driver - not including the length of the 180 degree bend.
Box_z = 32e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 10e-2; | Throat Area = Box_z * Throat_x
Mouth_x = 30e-2; | Mouth Area = Box_z * Mouth_x ... The area radiating into the listening room
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='830500' | Write the name of the driver which should be simulated here
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z}
Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z}
Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}
Freddy"
i made the sim with the following script. I figured the variables out of William Cowans schematic of the 30hz horn. When calculating the length of the horn, only take into account the straight parts without the bend, since the acoustic mass i used in the script should handle it. Thats why the length is 330cm.
I included the parameters for one of the "tapped horn for dummies" drivers for Patrick Bateman. It shouldnt be too complicated to simulate the horn with two drivers. For this i can again point to the manual on page 65 and following where a box with two drivers is simulated, taking into account the physical distance between the drivers, which could be more accurate than changing the TS parameters and handle it as a single one.
Def_Driver '830500'
dD=26cm |Piston
fs=18.1Hz Mms=166.3g Qms=3.7
Bl=17.6Tm Re=3.5ohm Le=4.2mH ExpoLe=0.618
Def_Driver '55-2421'
dD=26cm |Piston
fs=29.1Hz Mms=59.78g Qms=14
Bl=12.99Tm Re=3.4ohm Le=2.47mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 26e-2; | The outer driver diameter
Hornlength = 330e-2; | The length of the horn including the ducts around the driver - not including the length of the 180 degree bend.
Box_z = 32e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 10e-2; | Throat Area = Box_z * Throat_x
Mouth_x = 30e-2; | Mouth Area = Box_z * Mouth_x ... The area radiating into the listening room
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='830500' | Write the name of the driver which should be simulated here
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z}
Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z}
Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}
I don't have to change the "mass" parameter do I???
Here's what I used, but it's different than what you posted. The drivers are in series, which raises the BL. It's also a different enclosure - it's basically a seventy two inch long sonotube divided in half.
If you ask me the response is pretty darn good. And anyone could build this in under two hours!
###########################################
Def_Driver '55-2421x2'
dD=24.4cm |Piston
fs=30.95Hz Mms=119.58g Qms=12.29
Bl=25.08Tm Re=6.8ohm Le=4.84mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 25.4e-2; | The outer driver diameter
Hornlength = 335e-2; | The overall length of the horn including the ducts around the driver
Box_z = 12.7e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 12.65e-2; | Throat Area = Box_z * Throat_x
Mouth_x =12.75e-2; | Mouth Area = Box_z * Mouth_x
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='55-2421x2'
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}
Here's what I used, but it's different than what you posted. The drivers are in series, which raises the BL. It's also a different enclosure - it's basically a seventy two inch long sonotube divided in half.
If you ask me the response is pretty darn good. And anyone could build this in under two hours!
An externally hosted image should be here but it was not working when we last tested it.
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Def_Driver '55-2421x2'
dD=24.4cm |Piston
fs=30.95Hz Mms=119.58g Qms=12.29
Bl=25.08Tm Re=6.8ohm Le=4.84mH ExpoLe=0.618
Def_Const | all sizes in centimeters
{
| Input Data
DriverSize = 25.4e-2; | The outer driver diameter
Hornlength = 335e-2; | The overall length of the horn including the ducts around the driver
Box_z = 12.7e-2; | The depth of the box (z is constant - x & y get bigger from throat to mouth)
Throat_x = 12.65e-2; | Throat Area = Box_z * Throat_x
Mouth_x =12.75e-2; | Mouth Area = Box_z * Mouth_x
| Experimental Data
Mass = 1.85/(Throat_x+((Mouth_x-Throat_x)/2));
Mass2 = 1.85/Box_z; | I dont know which dimension fits the accoustic mass of the bend. One can try both, "Mass" will be used in the calculation, "Mass2" will be ignored.
}
| Horn Modell
System 'Tapped Horn'
Driver 'D' Node=2=0=100=105 Def='55-2421x2'
Duct 'D1' Node=100 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Duct 'D2' Node=100=101 WD={Throat_x} HD={Box_z} Len={Driversize/2}
Waveguide 'W1' Node=101=102 WTh={Throat_x} HTh={Box_z} WMo={Throat_x+((Mouth_x-Throat_x)/2)} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
AcouMass 'Bend1' Node=102=103 Ma={Mass}
AcouMass 'Bend2' Node=103=104 Ma={Mass}
Waveguide 'W2' Node=104=105 WTh={Throat_x+((Mouth_x-Throat_x)/2)} HTh={Box_z} WMo={Mouth_x} HMo={Box_z} Len={(Hornlength/2)-DriverSize} Conical
Duct 'D3' Node=105=106 WD={Mouth_x} HD={Box_z} Len={DriverSize}
Radiator 'Rad1' Node=106 WD={Mouth_x} HD={Box_z}