I'v been browsing through the messages - a ton of excellent projects and ideas here! I thought I might get some pointers/help on a project I am starting to put together.
I have a 8" Kicker Comp. speaker (originally a car stereo sub) that runs a 4ohm and I want to build a small sub box for my home theater system. (I already have some 3/4" MDF and the speaker, so the only thing to add would be an amp once the box is done).
heres some specs off Kicker's newest 8" sub, this is an older model so there may be slight differences, im sure.
Vas 0.75
Qts 0.547
Fs 36.8
Qms 10.179
Qes 0.578
Pmax 100
Xmax (mm)7.5
SPL 84.5
The box I am thinking about building would put the sub downward firing with a vent at the top (?) of the box in the back (?). My ideal box size looks to be somewhere around 1.18cuFt (I used spreadsheets found online to do my calcs.)
I posted a rough sketch (MS Paint) of what it should look like.
My questions are this:
1) is there much difference in downward firing vs. side or top mount for home theater? I was told there was by a sub salesman at a store, but he may have just been trying to sell me something 🙂
2) I had planned on using a vent (width of box) for looks and tuning - is this a good idea or should I stick with a port. I think I want to go ported instead of sealed to get a little lower response from the sub.
3) Does it matter where the vent is located and can it have a 90° bend in it? (again, according to my calcs, my vent should be 2" high by 10" wide by 14" long for proper tuning (~45hz)) - if I want to try tuning it to 40hz then the port would need to be almost 20"long - is that getting out of hand??
4) Do I need anything underneath the sub (it would be on a carpet)
5) is this a good idea (the box type etc.) for this sub? I've also thought about side mounting so the vent does not need to be as long.
Thanks for any and all responses!!! Any inaccuracies in calcs, etc. are to be expected as I am fairly new at the math behind sound.
Mike
I have a 8" Kicker Comp. speaker (originally a car stereo sub) that runs a 4ohm and I want to build a small sub box for my home theater system. (I already have some 3/4" MDF and the speaker, so the only thing to add would be an amp once the box is done).
heres some specs off Kicker's newest 8" sub, this is an older model so there may be slight differences, im sure.
Vas 0.75
Qts 0.547
Fs 36.8
Qms 10.179
Qes 0.578
Pmax 100
Xmax (mm)7.5
SPL 84.5
The box I am thinking about building would put the sub downward firing with a vent at the top (?) of the box in the back (?). My ideal box size looks to be somewhere around 1.18cuFt (I used spreadsheets found online to do my calcs.)
I posted a rough sketch (MS Paint) of what it should look like.
My questions are this:
1) is there much difference in downward firing vs. side or top mount for home theater? I was told there was by a sub salesman at a store, but he may have just been trying to sell me something 🙂
2) I had planned on using a vent (width of box) for looks and tuning - is this a good idea or should I stick with a port. I think I want to go ported instead of sealed to get a little lower response from the sub.
3) Does it matter where the vent is located and can it have a 90° bend in it? (again, according to my calcs, my vent should be 2" high by 10" wide by 14" long for proper tuning (~45hz)) - if I want to try tuning it to 40hz then the port would need to be almost 20"long - is that getting out of hand??
4) Do I need anything underneath the sub (it would be on a carpet)
5) is this a good idea (the box type etc.) for this sub? I've also thought about side mounting so the vent does not need to be as long.
Thanks for any and all responses!!! Any inaccuracies in calcs, etc. are to be expected as I am fairly new at the math behind sound.
Mike
Attachments
Looks like a great idea
Looks good. As far as the port, well, try to keep the port away from an inside wall approx. the same distance as the width of the port.
As far as were to put it, usually (I have found) put it on the same face as the driver, if you don't want to do that, move the port to take advantage of "wall loading, or corner loading" basically fire the port against a wall/corner...have to play with distance though.
Have fun, she should slam!
Rino
Looks good. As far as the port, well, try to keep the port away from an inside wall approx. the same distance as the width of the port.
As far as were to put it, usually (I have found) put it on the same face as the driver, if you don't want to do that, move the port to take advantage of "wall loading, or corner loading" basically fire the port against a wall/corner...have to play with distance though.
Have fun, she should slam!
Rino
port?
So what you're saying here is that instead of putting the port against the top wall of the speaker that I should set it down a few inches? Is that correct?
In the vented designs I looked at the vent was flush against the wall (used part of the wall as one wall of the vent, actually). I like this as it would save wood.
Mike
So what you're saying here is that instead of putting the port against the top wall of the speaker that I should set it down a few inches? Is that correct?
In the vented designs I looked at the vent was flush against the wall (used part of the wall as one wall of the vent, actually). I like this as it would save wood.
Mike
Hey Mike
You have the correct idea about using a "slot port", they work very well. The only thing I am saying to consider is to make sure that the end (inside the enclosure) of the port isn't working directly against a wall. The rule of thumb is to keep the end of the port (the inside of the enclosure end) a minimum distance away from it's parallel wall. Say you were to use a 4" round port, keep the port a minimum of 4" away from a parallel wall.
/-------space 4" from wall------/PORTPORTPORTPORTPORT/
Wish I could draw it better for you...can't figure how to do that on here yet.
Hope this helps
Rin
You have the correct idea about using a "slot port", they work very well. The only thing I am saying to consider is to make sure that the end (inside the enclosure) of the port isn't working directly against a wall. The rule of thumb is to keep the end of the port (the inside of the enclosure end) a minimum distance away from it's parallel wall. Say you were to use a 4" round port, keep the port a minimum of 4" away from a parallel wall.
/-------space 4" from wall------/PORTPORTPORTPORTPORT/
Wish I could draw it better for you...can't figure how to do that on here yet.
Hope this helps
Rin
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