Can anyone suggest how this would be modeled?
Drivers would likely be the 18 sounds 18LW2400.
see here for a picture/configuration.
New Push-Pull 15" - Speakerplans.com Forums - Page 1
Targets are-
1) -3db at 30hz and 120hz,
2) 600l max cab size (preferably smaller)
3) max 600mm in one of the dimentions (can get through doorways)
Winisd, gives a calculation for 6th order bandpass, but I don't know if listing 2 drivers simulates what I'm doing or not.
Drivers would likely be the 18 sounds 18LW2400.
see here for a picture/configuration.
New Push-Pull 15" - Speakerplans.com Forums - Page 1
Targets are-
1) -3db at 30hz and 120hz,
2) 600l max cab size (preferably smaller)
3) max 600mm in one of the dimentions (can get through doorways)
Winisd, gives a calculation for 6th order bandpass, but I don't know if listing 2 drivers simulates what I'm doing or not.
Hi
Targets are- 1) -3db at 30hz
It's not going to happen, or even close in that box !
See the graph from New Push-Pull 15" - Speakerplans.com Forums - Page 5 https://dl.dropboxusercontent.com/u/64726577/PushPull_LR48@150Hz.PNG
WinISD does do 6BP, & PP but not as shown in your link.
I would consider 2 X Reflex or Tapped Horns 🙂
Targets are- 1) -3db at 30hz
It's not going to happen, or even close in that box !
See the graph from New Push-Pull 15" - Speakerplans.com Forums - Page 5 https://dl.dropboxusercontent.com/u/64726577/PushPull_LR48@150Hz.PNG
WinISD does do 6BP, & PP but not as shown in your link.
I would consider 2 X Reflex or Tapped Horns 🙂
PPSL is not what you mean if you want PP, that's a whole other thing and impossible in a 6th order BP box.
I hate abbreviations and that's one of the reasons (easy misunderstanding or wrongly used), but... everybody uses them...😉
I hate abbreviations and that's one of the reasons (easy misunderstanding or wrongly used), but... everybody uses them...😉
maybe just model back chamber as a normal BR
as for calculating the front slot(bandpass), I suggest to look at the bandpass mids in a Danley synergy/unity horn
6th order may not be far from it, just more widebanded .... that is if your actual slot load really works like that
-3dB at 32hz (with a Q=2 32hz high-pass filter).
Will handle 2.4KW on sine wave without exceeding x-max, probably 5KW on typical program material.
The 103.7dB/2.83V/1M at 50hz includes about 3dB of boost from the Q=2 32hz filter.
8 cu ft net volume for the drivers, about 2'x2.5'x3' external using 3/4" ply.
Might look like an OHM PUKK 218 (or my 31hz PPSL).
This is only 425L gross, you might play around with a bit bigger box size if you like, but your Fs is a bit high for 30hz tuning. 10 cu ft net tuned to 30hz doesn't look too bad, 20" long ports, -3dB at 30hz.
---------------------
Driver Properties
Name: 18LW2400
Type: Standard one-way driver
Company: Eighteen Sound
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Fs = 35 Hz
Qms = 7.2
Vas = 230 liters
Cms = 0.108 mm/N
Mms = 191.6 g
Rms = 5.852 kg/s
Xmax = 9.5 mm
Xmech = 25 mm
P-Dia = 394.9 mm
Sd = 1225 sq.cm
P-Vd = 1.164 liters
Qes = 0.32
Re = 5 ohms
Le = 1.35 mH
Z = 8 ohms
BL = 25.66 Tm
Pe = 1200 watts
Qts = 0.306
no = 2.971 %
1-W SPL = 96.88 dB
2.83-V SPL = 98.92 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 10 cu.ft
Fb = 30 Hz
QL = 5.911
F3 = 29.91 Hz
Fill = minimal
No. of Vents = 2
Vent shape = rectangle
Vent ends = one flush
Hv = 10.75 in
Wv = 4 in
Lv = 19.9 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 30 Hz
Qx = 2
Will handle 2.4KW on sine wave without exceeding x-max, probably 5KW on typical program material.
The 103.7dB/2.83V/1M at 50hz includes about 3dB of boost from the Q=2 32hz filter.
8 cu ft net volume for the drivers, about 2'x2.5'x3' external using 3/4" ply.
Might look like an OHM PUKK 218 (or my 31hz PPSL).
This is only 425L gross, you might play around with a bit bigger box size if you like, but your Fs is a bit high for 30hz tuning. 10 cu ft net tuned to 30hz doesn't look too bad, 20" long ports, -3dB at 30hz.
---------------------
Driver Properties
Name: 18LW2400
Type: Standard one-way driver
Company: Eighteen Sound
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Fs = 35 Hz
Qms = 7.2
Vas = 230 liters
Cms = 0.108 mm/N
Mms = 191.6 g
Rms = 5.852 kg/s
Xmax = 9.5 mm
Xmech = 25 mm
P-Dia = 394.9 mm
Sd = 1225 sq.cm
P-Vd = 1.164 liters
Qes = 0.32
Re = 5 ohms
Le = 1.35 mH
Z = 8 ohms
BL = 25.66 Tm
Pe = 1200 watts
Qts = 0.306
no = 2.971 %
1-W SPL = 96.88 dB
2.83-V SPL = 98.92 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box w/ Active HP Filter
Shape: Prism, square (optimum)
Vb = 10 cu.ft
Fb = 30 Hz
QL = 5.911
F3 = 29.91 Hz
Fill = minimal
No. of Vents = 2
Vent shape = rectangle
Vent ends = one flush
Hv = 10.75 in
Wv = 4 in
Lv = 19.9 in
-----------------------------------------
Active 12 dB/oct. HP Filter
Fx = 30 Hz
Qx = 2
Last edited:
Hi Djk,
Im having difficulty understanding the internal configuration of the box for this- a 6th order bandpass makes it impossible to see the drivers- so how does this work so that the drivers are visible??
Im having difficulty understanding the internal configuration of the box for this- a 6th order bandpass makes it impossible to see the drivers- so how does this work so that the drivers are visible??
Simple, it's not a bandpass in the frequency range that it is normally run in.
6th order=vented box with EQ
BP6A=parallel tuned bandpass
BP6B=series tuned bandpass
The PPSL may be applied to sealed, OB, vented, etc.
6th order=vented box with EQ
BP6A=parallel tuned bandpass
BP6B=series tuned bandpass
The PPSL may be applied to sealed, OB, vented, etc.
There's not much path between the two sections of the box, and the slot on one side, vents on the other, make it look more like 2 coupled tuned boxes.
Basically, a neat looking design that would be prone to misbehavior. Classic PPSL design would be vastly preferred.
Basically, a neat looking design that would be prone to misbehavior. Classic PPSL design would be vastly preferred.
OHM has left a little space between the drivers so they can use Neo magnet drivers as well as ferrite.
The dual 12, 15, and 18 family, all with Neo magnets.
My 31hz version, the cabinets and drivers date back to 1988.
An externally hosted image should be here but it was not working when we last tested it.
The dual 12, 15, and 18 family, all with Neo magnets.
An externally hosted image should be here but it was not working when we last tested it.
My 31hz version, the cabinets and drivers date back to 1988.
Last edited:
The area between the "top" driver and the vent in the Ohm seems very small- I'd think that'd introduce some misbehavior.
I always use as big a vent as I can fit in the box (or a PR).
Pasi (OHM), says their double 18 is tuned so low there is little program material down there.
My original prototypes had the same vent area as the slot area for the driver plenum.
Pasi (OHM), says their double 18 is tuned so low there is little program material down there.
My original prototypes had the same vent area as the slot area for the driver plenum.
Pasi has some reason for doing it that way, but refuses to share his thoughts. I have no idea why he did it that way.
I like his choice of BMS drivers, but the MSRP of the boxes seems a bit steep.
I like his choice of BMS drivers, but the MSRP of the boxes seems a bit steep.
I'm no BassBox expert, but if I may bring attention to a few things I noticed:
...Without the active EQ applied. (middle image, blue trace)
Once the active filter/EQ is applied (middle image, magenta trace), they will be exceeding xmax by over 5mm at 40Hz (and over 7mm at 21Hz) at 2400W input. Taking power compression into consideration, we move down about 2mm.
With the 10 cu. ft. box, xmax increases by ~2 more mm. Halve the power in and excursion reduces by ~2mm. Always a compromise.
(Excursion plots comparing enclosure volumes (8 ft3 vs 10 ft3) w/1200W & 2400W w/djk's input information shown below)
-3dB at 32hz (with a Q=2 32hz high-pass filter).
...Without the active EQ applied. (middle image, blue trace)
Once the active filter/EQ is applied (middle image, magenta trace), they will be exceeding xmax by over 5mm at 40Hz (and over 7mm at 21Hz) at 2400W input. Taking power compression into consideration, we move down about 2mm.
With the 10 cu. ft. box, xmax increases by ~2 more mm. Halve the power in and excursion reduces by ~2mm. Always a compromise.
(Excursion plots comparing enclosure volumes (8 ft3 vs 10 ft3) w/1200W & 2400W w/djk's input information shown below)
Attachments
You have to turn off the EQ to see how much power it can handle vs excursion.
When you enter 2.4KW with the EQ on and a Q=2 the excursion curve is drawn with 6dB of boost, or 9.6KW input.
When you enter 2.4KW with the EQ on and a Q=2 the excursion curve is drawn with 6dB of boost, or 9.6KW input.
Thanks for chiming in, djk. That's some much needed info. It's also the answer I was after some year(s) ago in the other PPSL thread when inquiring about a driver's power handling capabilities vs BassBox's EQ.
So, check excursion w/o EQ; check freq response & output w/EQ. "Poifect!"
At 2.4KW input with the filter & EQ applied, how much power are the drivers seeing at the cutoff freq?
So, check excursion w/o EQ; check freq response & output w/EQ. "Poifect!"
At 2.4KW input with the filter & EQ applied, how much power are the drivers seeing at the cutoff freq?
The reason may be very simple. The PUKK 218 has 10 handles... I believe the slot and port are shaped and positioned so he can fit handles on all sides without having to put them in the port or slot. It is possible that the appearance has priority over minor misbehavior. What do you think?
An externally hosted image should be here but it was not working when we last tested it.
- Status
- Not open for further replies.