hey everyone,
ive been looking everywhere on the net to find an enclosure that i can create for my home theatre system.
ive already made the 'wicked one' from decware, but just recently ive discovered that some measurements were off which is why the sub didnt sound really REALLy nice, which is really dissapointing for me as that sub took so long to make.
the equipment that i have are
2 x 10" Response XL subs
1 x 350wrms (4ohm) jaycar home amp
and a lot of wire + a hundred or so screws
I have been trying really hard to understand howto find measurements and such for a subwoofer enclosure that i can make but its just taking too much time and i really dont trust myself to come to any conclusion about dimensions when it comes to something that im so new in.
ANY measurements or any links to sites that can help an idiot make an enclosure would be so so soooooooo very much appreciated.
The specs of the subs are :
-Nominal impedance: 4 ohms (both 8ohm coils in parallel)
-Power rating: 200WRMS (total for both coils at 4ohm)
-Sensitivity at 1W@1m: 87.31dB
-Voice coil resistance (Re): 3.5 ohms
-Resonant frequency (Fs): 24.38 hz
-Mechanical Q factor (Qms): 2.639
-Electrical Q factor (Qes): .337
-Total Q factor (Qts): .299
-Equivalent volume (Vas): 73.19Lt
-Cone Area: 0.0346 sq meter
-Voice Coil Diameter: 50mm
-Xmax: 10.5mm
Speaker dimensions: A 260, B 246, C 240
Thanks,
lach
ive been looking everywhere on the net to find an enclosure that i can create for my home theatre system.
ive already made the 'wicked one' from decware, but just recently ive discovered that some measurements were off which is why the sub didnt sound really REALLy nice, which is really dissapointing for me as that sub took so long to make.
the equipment that i have are
2 x 10" Response XL subs
1 x 350wrms (4ohm) jaycar home amp
and a lot of wire + a hundred or so screws
I have been trying really hard to understand howto find measurements and such for a subwoofer enclosure that i can make but its just taking too much time and i really dont trust myself to come to any conclusion about dimensions when it comes to something that im so new in.
ANY measurements or any links to sites that can help an idiot make an enclosure would be so so soooooooo very much appreciated.
The specs of the subs are :
-Nominal impedance: 4 ohms (both 8ohm coils in parallel)
-Power rating: 200WRMS (total for both coils at 4ohm)
-Sensitivity at 1W@1m: 87.31dB
-Voice coil resistance (Re): 3.5 ohms
-Resonant frequency (Fs): 24.38 hz
-Mechanical Q factor (Qms): 2.639
-Electrical Q factor (Qes): .337
-Total Q factor (Qts): .299
-Equivalent volume (Vas): 73.19Lt
-Cone Area: 0.0346 sq meter
-Voice Coil Diameter: 50mm
-Xmax: 10.5mm
Speaker dimensions: A 260, B 246, C 240
Thanks,
lach
hey guys,
yeah ive plugged it into winisd but in the diagram it shows only 1 sub in the enclosure and it doesnt seem to change when i choose 2 driver configuration.
i also wanted to know if it makes a huge difference if i just put 2 drivers in the front of the enclosure like side by side and just double the room inside the enclosure??
in the specifications it tells me that the recommended size for a vented enclosure is :Cabinet Dimensions (internal): 502(H) x 314(W) x 194 (D) mm
does this mean that if i double the dimensions and just wack 2 subs in beside each other and add an extra port taht it will work?
i really am pretty new to this sought of thing, but im really enthusiastic its just i have no one else around to help me out when i have a question.
thanks,
lach
yeah ive plugged it into winisd but in the diagram it shows only 1 sub in the enclosure and it doesnt seem to change when i choose 2 driver configuration.
i also wanted to know if it makes a huge difference if i just put 2 drivers in the front of the enclosure like side by side and just double the room inside the enclosure??
in the specifications it tells me that the recommended size for a vented enclosure is :Cabinet Dimensions (internal): 502(H) x 314(W) x 194 (D) mm
does this mean that if i double the dimensions and just wack 2 subs in beside each other and add an extra port taht it will work?
i really am pretty new to this sought of thing, but im really enthusiastic its just i have no one else around to help me out when i have a question.
thanks,
lach
>but in the diagram it shows only 1 sub in the enclosure and it doesnt seem to change when i choose 2 driver configuration.
====
For a given alignment, adding a driver requires that you double the Vb and vents.
====
>i also wanted to know if it makes a huge difference if i just put 2 drivers in the front of the enclosure like side by side
====
This isn't a good plan since it will cause excessive vibration unless it's extremely massive, so mount them bipolar (on opposite sides) to cancel them out.
====
>in the specifications it tells me that the recommended size for a vented enclosure is :Cabinet Dimensions (internal): 502(H) x 314(W) x 194 (D) mm
====
OK, not being familiar with this particular driver, I assume you're quoting published specs which may be very inaccurate, so any design based on them could be way off.
If they were mine, I'd try them in ~2.84ft^3 net, tuned to ~25Hz. IOW after the drivers and vent volumes are deducted, though some folks just add 10%, bumping it up to ~3.124ft^3. This equates to inside dims of 28.38" x 17.53" x 10.84". Due to the long vents required if tubular, I would use a shelf vent 1.25"H x 6.75"W x 12.25"L on one of the other sides opposite the drivers.
====
>i really am pretty new to this sought of thing, but im really enthusiastic its just i have no one else around to help me out when i have a question.
====
Well, there's plenty of help on the net......quite a bit of it is even accurate nowadays.
GM
====
For a given alignment, adding a driver requires that you double the Vb and vents.
====
>i also wanted to know if it makes a huge difference if i just put 2 drivers in the front of the enclosure like side by side
====
This isn't a good plan since it will cause excessive vibration unless it's extremely massive, so mount them bipolar (on opposite sides) to cancel them out.
====
>in the specifications it tells me that the recommended size for a vented enclosure is :Cabinet Dimensions (internal): 502(H) x 314(W) x 194 (D) mm
====
OK, not being familiar with this particular driver, I assume you're quoting published specs which may be very inaccurate, so any design based on them could be way off.
If they were mine, I'd try them in ~2.84ft^3 net, tuned to ~25Hz. IOW after the drivers and vent volumes are deducted, though some folks just add 10%, bumping it up to ~3.124ft^3. This equates to inside dims of 28.38" x 17.53" x 10.84". Due to the long vents required if tubular, I would use a shelf vent 1.25"H x 6.75"W x 12.25"L on one of the other sides opposite the drivers.
====
>i really am pretty new to this sought of thing, but im really enthusiastic its just i have no one else around to help me out when i have a question.
====
Well, there's plenty of help on the net......quite a bit of it is even accurate nowadays.
GM
Tuning a vented box is very easy. Cut off a piece of PVC tube of dia 2.5 inches and 4.1 inches long, cut a hole in the front baffle or back of the box and insert this tube into a 54Litres box and your bass response will look roughly like what is shown in the black graph.
If you prefer to use a smaller box, the red graph is optimal response. With a box of 27Litres internally, use a tube of 2 inch in dia and roughly 7.8 inches long and you will be tuning the box to 33Hz and the character of your bass output will look roughly like the red line.
For sub-woofers, bandpass designs are very popular. This simulation shows your response XL is also well suited for bandpass. With a -3dB at 36Hz and 95Hz and a box of only 28Litres, makes a very appealing sub-woofer.
If you prefer to use a smaller box, the red graph is optimal response. With a box of 27Litres internally, use a tube of 2 inch in dia and roughly 7.8 inches long and you will be tuning the box to 33Hz and the character of your bass output will look roughly like the red line.
For sub-woofers, bandpass designs are very popular. This simulation shows your response XL is also well suited for bandpass. With a -3dB at 36Hz and 95Hz and a box of only 28Litres, makes a very appealing sub-woofer.
Attachments
could someone also tell me whether it matters if i change the dimensions to suit my room conditions? still keeping the volume consistent of course but would doing so alter any resonating features (anything??) of the enclosure?
if i was to use a tube vent though, what would the required size of it be?
thanks again,
lach
if i was to use a tube vent though, what would the required size of it be?
thanks again,
lach
As long as the volume of the enclosure's interior is kept the same, I don't see a problem. However, if you make the depth of the enclosure too small you don't allow the rear-wave work to it's fullest use {especially in a vented enclosure}. Too small, meaning less than three inches behind the driver.
> whether it matters if i change the dimensions to suit my room conditions? still keeping the volume consistent of course but would doing so alter any resonating features (anything??) of the enclosure?
As far as the bass response goes: you can adjust the relative dimensions over a very wide range.
A cube would use the least plywood, if you could get plywood in any size.
In a wide-range woofer, you almost never want a literal CUBE. Each dimension has a resonance, typically upper mid-bass or mid-range. If all three dimensions are the same, that resonance gets very strong, and even packed stuffing may not mute it. I would compute a cube, then make one side 0.8X and another 1.25X (1.25 by 1.0 by 0.8) because that gives a nice spread between dimensions and spreads the resonances.
In a true SUB-woofer, not getting any upper bass, a cube or near-cube is often not a problem.
In practice you want dimensions a bit under 16", 24", etc, to make the most use of a 4x8 sheet.
If your room dictates otherwise, do what fits.
When the long dimension gets to be 2 or 3 times longer than the short dimension, you tend to be buying a lot of lumber and you also tend to need a lot of bracing on the long sides.
You get in trouble if you go VERY long-and-skinny: don't make one dimension 10 feet because it will start to work like an organ-pipe instead of a bottle resonator. (There is a whole separate school of theory for long-skinny pipes; it is not as developed as the "box" types and I doubt it has any core advantage, though it does have attractions.)
The internal volume is important but not real critical. See MCP's plot of two boxes, one TWICE as big as the other. Above 50Hz there is "no" difference (+/-0.5dB), and the biggest difference is only 3.5dB and about one note wide.
However the internal volume is critical when you try to calculate the PORT. Especially when you get to very over-sized boxes. You can use excess volume and tune-up the low-end by leveraging that excess volume, but the more leverage you use the more fussy the tuning becomes. I've never had any luck predicting port sizes, I always resort to tests. Run a sweep tome 20-80Hz and put your ear close to the port. If you sweep down from 80 to 20, you will hear sound from the woofer cone, then that fades and is overwhelmed by sound from the port, then that fades. The maximum port-output frequency is the tuning, and should match the number in your bass-reflex program or formula.
As far as the bass response goes: you can adjust the relative dimensions over a very wide range.
A cube would use the least plywood, if you could get plywood in any size.
In a wide-range woofer, you almost never want a literal CUBE. Each dimension has a resonance, typically upper mid-bass or mid-range. If all three dimensions are the same, that resonance gets very strong, and even packed stuffing may not mute it. I would compute a cube, then make one side 0.8X and another 1.25X (1.25 by 1.0 by 0.8) because that gives a nice spread between dimensions and spreads the resonances.
In a true SUB-woofer, not getting any upper bass, a cube or near-cube is often not a problem.
In practice you want dimensions a bit under 16", 24", etc, to make the most use of a 4x8 sheet.
If your room dictates otherwise, do what fits.
When the long dimension gets to be 2 or 3 times longer than the short dimension, you tend to be buying a lot of lumber and you also tend to need a lot of bracing on the long sides.
You get in trouble if you go VERY long-and-skinny: don't make one dimension 10 feet because it will start to work like an organ-pipe instead of a bottle resonator. (There is a whole separate school of theory for long-skinny pipes; it is not as developed as the "box" types and I doubt it has any core advantage, though it does have attractions.)
The internal volume is important but not real critical. See MCP's plot of two boxes, one TWICE as big as the other. Above 50Hz there is "no" difference (+/-0.5dB), and the biggest difference is only 3.5dB and about one note wide.
However the internal volume is critical when you try to calculate the PORT. Especially when you get to very over-sized boxes. You can use excess volume and tune-up the low-end by leveraging that excess volume, but the more leverage you use the more fussy the tuning becomes. I've never had any luck predicting port sizes, I always resort to tests. Run a sweep tome 20-80Hz and put your ear close to the port. If you sweep down from 80 to 20, you will hear sound from the woofer cone, then that fades and is overwhelmed by sound from the port, then that fades. The maximum port-output frequency is the tuning, and should match the number in your bass-reflex program or formula.
Some bass is very airy, like bandpass subs. Some gives good punch but lacks the vibration. Yet others are able to "throw" longer distances. Apart from all these, there is also a question of room interaction and the quality of the driver.
A good approach is to get a test box done cheaply and listen to it with different tube lengths. Effectively, you will be tuning the sub to your room. If it is to your liking, proceed to make a proper box. Otherwise, make another test box and more listening. If still not to your liking, consider changing woofers.
A good approach is to get a test box done cheaply and listen to it with different tube lengths. Effectively, you will be tuning the sub to your room. If it is to your liking, proceed to make a proper box. Otherwise, make another test box and more listening. If still not to your liking, consider changing woofers.
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