Hi ,
I'd love some help with a Sub project I want to build.
I've got 4 Morel 222 drivers available doing nothing.
The specs are as follows :
Fs=31Hz
Re=5.2ohms
L=0.5mH
Xmax=3.5mm
Qms=3.74
Qes=0.95
Qts=0.75
Vas=70litres
Cone=219cm2
Power=120W
Z=8ohm
When I plug the figures into my software it suggests ridiculously
large enclosure sizes >1000litres ??
Can anyone suggest an enclosure design utilizing these drivers
sealed/bass reflex/bandpass.....I don't mind. Good low bass , but
not "boomy" for use with HT & Music.
Thanks
Andrew
I'd love some help with a Sub project I want to build.
I've got 4 Morel 222 drivers available doing nothing.
The specs are as follows :
Fs=31Hz
Re=5.2ohms
L=0.5mH
Xmax=3.5mm
Qms=3.74
Qes=0.95
Qts=0.75
Vas=70litres
Cone=219cm2
Power=120W
Z=8ohm
When I plug the figures into my software it suggests ridiculously
large enclosure sizes >1000litres ??
Can anyone suggest an enclosure design utilizing these drivers
sealed/bass reflex/bandpass.....I don't mind. Good low bass , but
not "boomy" for use with HT & Music.
Thanks
Andrew
With that kind of Q, go for a sealed box
When Qc = 1.25, box volume is 3.5 ft3.
If you do a compound woofer configuration, the box will have two woofers in it and be 1/2 original enclosure size, 1.75 ft3. Efficiency will be that of a single woofer (assuming a 4 ohm parallel connection).
-andy
btw, if you can make it any larger than 1.75, i would recomend that you do so
I've never done anything with woofers with that high of a Q value, if anyone has any other suggestions please share.
When Qc = 1.25, box volume is 3.5 ft3.
If you do a compound woofer configuration, the box will have two woofers in it and be 1/2 original enclosure size, 1.75 ft3. Efficiency will be that of a single woofer (assuming a 4 ohm parallel connection).
-andy
btw, if you can make it any larger than 1.75, i would recomend that you do so
I've never done anything with woofers with that high of a Q value, if anyone has any other suggestions please share.
Okay, here are some suggestions.
Four boxes of different configurations. Two are 2 cu ft,
two are 3 cu ft.
Red. 3 cu ft. Closed box. Least output of the four.
Orange. Bandpass. 3 cubic ft total. 1.5 cu ft front chamber, 1.5 cu ft rear chamber. Tuned to 48 Hz.
Lt. Blue. Bandpass. 2 cubic ft total. 1.2 cu ft front, .8 cu ft rear. Front tuned to 60 Hz.
Dark Blue. Bandpass. 2 cubic ft total. .7 cubic ft front. 1.3 cu ft rear. Front tuned to 48 Hz.
Note that the bandpass boxes exhibit higher sensitivity and/or bass extension than the sealed.
Except for the dark blue, the depressions in the middle are not so unmanageable-2 or 3 db. Bear in mind that when a bandpass is near a corner, the tuning frequency is emphasized most of all, and that will fill in the middle depression.
The front chamber can also be tuned with a 10" or bigger passive radiator.
If you want less than 2 cubic feet, let me know,
but you are not going to get anywhere near 30 Hz output if it is smaller than that.
I have never built a bandpass box, but with the extra output it seems to put out, I plan to soon. I have also never used a passive radiator, but I understand the principles. I have built plenty of sealed and ported enclosures.
The graphs are only there to give you an idea of some possibilities.
Good luck!!
Four boxes of different configurations. Two are 2 cu ft,
two are 3 cu ft.
Red. 3 cu ft. Closed box. Least output of the four.
Orange. Bandpass. 3 cubic ft total. 1.5 cu ft front chamber, 1.5 cu ft rear chamber. Tuned to 48 Hz.
Lt. Blue. Bandpass. 2 cubic ft total. 1.2 cu ft front, .8 cu ft rear. Front tuned to 60 Hz.
Dark Blue. Bandpass. 2 cubic ft total. .7 cubic ft front. 1.3 cu ft rear. Front tuned to 48 Hz.
Note that the bandpass boxes exhibit higher sensitivity and/or bass extension than the sealed.
Except for the dark blue, the depressions in the middle are not so unmanageable-2 or 3 db. Bear in mind that when a bandpass is near a corner, the tuning frequency is emphasized most of all, and that will fill in the middle depression.
The front chamber can also be tuned with a 10" or bigger passive radiator.
If you want less than 2 cubic feet, let me know,
but you are not going to get anywhere near 30 Hz output if it is smaller than that.
I have never built a bandpass box, but with the extra output it seems to put out, I plan to soon. I have also never used a passive radiator, but I understand the principles. I have built plenty of sealed and ported enclosures.
The graphs are only there to give you an idea of some possibilities.
Good luck!!
Attachments
Found some more information which may help someone to help me !
The drivers were used in a Morel model MLP307 , 2 wired in parallel in a box with total of volume ~ 45 litres.
Each driver had it's own compartment of ~ 22 litres and each
compartment was rear vented with a aperedic?? port (not sure how to spell it) - (not a bass reflex port !)
These speakers had good low down performance , that's why I
thought of using these drivers.....
My "Spouse Factor" concludes that my sub needs to be built under
the coffee table , so I've got about 92 litres to play with.
So I'm trying to make the best of the available drivers & room space.
Many Thanks
The drivers were used in a Morel model MLP307 , 2 wired in parallel in a box with total of volume ~ 45 litres.
Each driver had it's own compartment of ~ 22 litres and each
compartment was rear vented with a aperedic?? port (not sure how to spell it) - (not a bass reflex port !)
These speakers had good low down performance , that's why I
thought of using these drivers.....
My "Spouse Factor" concludes that my sub needs to be built under
the coffee table , so I've got about 92 litres to play with.
So I'm trying to make the best of the available drivers & room space.
Many Thanks
Well, I don't know that much about aperiodic vents, but here is a page that explains things:
http://www.snippets.org/ldsg/boxes.php3#APERIODIC
Frankly, I think I would use one speaker in a 3 cubic foot bandpass enclosure, but that's just me.
I have seen other aperiodic designs using 2 chambers but have no link. I will post the link if I come across it.
Good luck.
http://www.snippets.org/ldsg/boxes.php3#APERIODIC
Frankly, I think I would use one speaker in a 3 cubic foot bandpass enclosure, but that's just me.
I have seen other aperiodic designs using 2 chambers but have no link. I will post the link if I come across it.
Good luck.
aperiodic vents
damp resonance impedence the same way adding 100% fiberglass fill does, according to Vance Dickason. This increases the effective size of an enclosure.
Do you plan to use all 4 woofers?
the bandpass idea is feasible, only large. How would the compound woofer setup compare soundwise? Could one design a coumpound woofer bandpass sub? I will see if I can find out.
andy
damp resonance impedence the same way adding 100% fiberglass fill does, according to Vance Dickason. This increases the effective size of an enclosure.
Do you plan to use all 4 woofers?
the bandpass idea is feasible, only large. How would the compound woofer setup compare soundwise? Could one design a coumpound woofer bandpass sub? I will see if I can find out.
andy
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