Its a dual 10" subwoofer with a dividing wall inside, I've sealed it all up as tight as a drum with tons of silicone and then I added some weather stripping around the drivers to make it even more sealed, it could literally hold water.
I'm going to resize the holes to fit in two Focal RSB-300 drivers so please do the math for those drivers and not the existing two 10" drivers: FOCAL RSB-300 AUDITOR 12" / 30cm SUBWOOFER DUAL 4 OHM 300W RMS 30Hz-500Hz | eBay
Here are the info/specs sheets for the Focal RSB-300:
http://www.focal-america.com/wp-content/uploads/2013/12/FP_auditor_RSB_300_EN.pdf
http://www.focal-america.com/wp-content/uploads/2013/12/FT_auditor_RSB_300.pdf
I listen to mostly EBM/Industrial music.
I've got the dimensions that were taken from the inside for each compartment (there are two):
240mm deep
325mm high
420mm wide
I need the port width and length in mm.
Thank you!
I'm going to resize the holes to fit in two Focal RSB-300 drivers so please do the math for those drivers and not the existing two 10" drivers: FOCAL RSB-300 AUDITOR 12" / 30cm SUBWOOFER DUAL 4 OHM 300W RMS 30Hz-500Hz | eBay
Here are the info/specs sheets for the Focal RSB-300:
http://www.focal-america.com/wp-content/uploads/2013/12/FP_auditor_RSB_300_EN.pdf
http://www.focal-america.com/wp-content/uploads/2013/12/FT_auditor_RSB_300.pdf
I listen to mostly EBM/Industrial music.
I've got the dimensions that were taken from the inside for each compartment (there are two):
240mm deep
325mm high
420mm wide
I need the port width and length in mm.
Thank you!
Hi VenusFly,
It depends on what the characteristics of the woofers are. Some simply don't work well as ported drivers. As a rule of thumb, a ported box will generally be larger than the sealed one by 1.6x to 2x for a woofer that would work in either box type. Don't forget that the volume of the port subtracts from the total box volume as well.
So, to start you need to get the Thiel & Small parameters for the actual drivers and plug them into a speaker design program. It will spit out the volume and from there you add the volume of the speaker that will be in the box, the port(s) volume, bracing and for the acoustic damping material. Pink fiberglass is 10% by volume uncompressed. So add these volumes to the volume the program gave you and it will come out right almost every time. Note that some woofers really don't "like" a ported box, just as some woofers that work great in a ported box are unsuitable for a sealed enclosure.
This isn't a case where you drill two holes and stick a pair of premade plastic port tubes in those holes!
-Chris
It depends on what the characteristics of the woofers are. Some simply don't work well as ported drivers. As a rule of thumb, a ported box will generally be larger than the sealed one by 1.6x to 2x for a woofer that would work in either box type. Don't forget that the volume of the port subtracts from the total box volume as well.
So, to start you need to get the Thiel & Small parameters for the actual drivers and plug them into a speaker design program. It will spit out the volume and from there you add the volume of the speaker that will be in the box, the port(s) volume, bracing and for the acoustic damping material. Pink fiberglass is 10% by volume uncompressed. So add these volumes to the volume the program gave you and it will come out right almost every time. Note that some woofers really don't "like" a ported box, just as some woofers that work great in a ported box are unsuitable for a sealed enclosure.
This isn't a case where you drill two holes and stick a pair of premade plastic port tubes in those holes!
-Chris
Might be best to simply leave it as a sealed unit and put in the two 12" drivers then.
I removed the cotton wool that I put in there and it got louder and I didn't hear any resonance going on so I'm going to leave it as that. I had enough cotton wool in there (pulled out of a pillow) that it filled up the entire cavity inside. So not suprised it was quieter.
I also had it setup before where I stapled some flattened cotton wool to the walls inside the sub and it didn't remove anything of consequence. I certainly didn't hear any resonances in the wood once it was removed. So now its just got no foam inside of it at all, bare wood.
The loudest sound I heard was the air coming from the drivers.
I removed the cotton wool that I put in there and it got louder and I didn't hear any resonance going on so I'm going to leave it as that. I had enough cotton wool in there (pulled out of a pillow) that it filled up the entire cavity inside. So not suprised it was quieter.
I also had it setup before where I stapled some flattened cotton wool to the walls inside the sub and it didn't remove anything of consequence. I certainly didn't hear any resonances in the wood once it was removed. So now its just got no foam inside of it at all, bare wood.
The loudest sound I heard was the air coming from the drivers.
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Hi VenusFly,
I would put the padding back in.
If you have a look at 8" drivers, or some 10" drivers you will find that the box size will fit for one, and they will have much lower bass than 12" woofers will have. 12" woofers generally need a much larger box than a car can fit.
I think you would learn a lot by getting a box design program and play with existing drivers that you can find the specs on. Try different woofers in the program and have a look at the size of the box, and also the low frequency cut-off point. You might see a trend that supports what I just told you, but it's much better to learn this yourself.
I think that starting with new drivers in a new box is exactly what you should do, and I applaud your willingness to do so. What you end up with will outperform "canned" speaker systems.
Oh, don't mount power amps on speaker boxes. They will get shaken apart over time.
-Chris
I would put the padding back in.
If you have a look at 8" drivers, or some 10" drivers you will find that the box size will fit for one, and they will have much lower bass than 12" woofers will have. 12" woofers generally need a much larger box than a car can fit.
I think you would learn a lot by getting a box design program and play with existing drivers that you can find the specs on. Try different woofers in the program and have a look at the size of the box, and also the low frequency cut-off point. You might see a trend that supports what I just told you, but it's much better to learn this yourself.
I think that starting with new drivers in a new box is exactly what you should do, and I applaud your willingness to do so. What you end up with will outperform "canned" speaker systems.
Oh, don't mount power amps on speaker boxes. They will get shaken apart over time.
-Chris
Roger.
Funny I was told that two 12" would produce lower frequencies better than a pair of 10"'s.
Got any suggestions?
There is a prefabbed ported dual 12" sub on ebay for $145 shipped. I've bought one of their single 12" sealed boxes before and it performed really well.
Aerpro Unibox Dual 12" Subwoofer Box (Ub12d2) | eBay
I don't want to take up too much boot space, the current dual 10" fits perfectly under the rear parcel shelf with a couple of mm to spare.
This dual 12" sub seems to be about the same size. So maybe I should just stick with the dual 10" sub. If its no larger then it won't perform any louder than the current dual 10" that I've got.
Roger. I do have some spots free in the boot where I can mount some plywood and the amps to. It will be a bit of a pain but not impossible. I've got the place where the old factory cd stacker used to be, I can mount an amp onto a plywood shelf there with room to spare. But it would be for powering the subwoofer only.
Felt like you were getting into my brain just then. Felt weird. Because I've done that before. Had no issues but I never really pounded subs hard for long periods before. I got my fix at home with an 18" ported sub long ago. usually in the car I just listen for a little while then turn it down.
So I might stick with the dual 10"....
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Hi VenusFly,
It's been decades since I designed speaker boxes, so I am unfamiliar with what is available. Other members could really help with this. One thing is for sure though, the laws of physics have not changed, nor have the specifications. When I was designing boxes (a lot), I used a program that I wrote myself that gave me the basic information. Today's programs do the same thing, except that you can choose more varieties of box types.
Another fact. The higher the order of the box, the more sensitive it will be for different drivers (same make and model) and air density changes, I usually stuck with a B4 alignment, or sealed enclosure.
The 12" drivers will cut off a lot higher since they are in the same volume box (approximately), but the cone area is approximately double that of the 10". Smaller volume of air acting on a much larger area will raise the resonance, not lower it. The person who told you this is either wrong (in general he is), or has a much more expensive speaker in the 12" compared to the 10" you have.
My largest systems used either 10", 15" or 18" drivers. The 12" size was an unhappy collection of drivers as far as performance was concerned. The 10" woofer would often out-perform the 12", and the next two sizes up really outperformed the 12" size. So it just didn't make sense to use a 12" driver. You could get away with just a mid and tweeter with the 10", but the larger ones do require an upper bass driver as well.
Your single 12" would outperform the dual 12" in a ported box about the same size. The physics dictates this to be true. The higher cone area would give you more "slam", but absolutely wouldn't put out deeper bass.
-Chris
It's been decades since I designed speaker boxes, so I am unfamiliar with what is available. Other members could really help with this. One thing is for sure though, the laws of physics have not changed, nor have the specifications. When I was designing boxes (a lot), I used a program that I wrote myself that gave me the basic information. Today's programs do the same thing, except that you can choose more varieties of box types.
Another fact. The higher the order of the box, the more sensitive it will be for different drivers (same make and model) and air density changes, I usually stuck with a B4 alignment, or sealed enclosure.
The 12" drivers will cut off a lot higher since they are in the same volume box (approximately), but the cone area is approximately double that of the 10". Smaller volume of air acting on a much larger area will raise the resonance, not lower it. The person who told you this is either wrong (in general he is), or has a much more expensive speaker in the 12" compared to the 10" you have.
My largest systems used either 10", 15" or 18" drivers. The 12" size was an unhappy collection of drivers as far as performance was concerned. The 10" woofer would often out-perform the 12", and the next two sizes up really outperformed the 12" size. So it just didn't make sense to use a 12" driver. You could get away with just a mid and tweeter with the 10", but the larger ones do require an upper bass driver as well.
Your single 12" would outperform the dual 12" in a ported box about the same size. The physics dictates this to be true. The higher cone area would give you more "slam", but absolutely wouldn't put out deeper bass.
-Chris
I might give away the dual 10" sub and put in two 6x9 subwoofers on the rear parcel shelf to keep down weight in my car. This dual 10" is pretty heavy and I don't want weight over the rear springs, if anything I want nothing in the boot.
If I get some high powered deep excursion woofers it should produce an adequate amount of bass from the rear parcel shelf and work out cheaper in the end because I won't have to put in the subwoofer, I can just put them on the shelf.
If I get some high powered deep excursion woofers it should produce an adequate amount of bass from the rear parcel shelf and work out cheaper in the end because I won't have to put in the subwoofer, I can just put them on the shelf.
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They should pound somewhat having the whole boot for a box: (2) Rockville RVL69W 6x9" 600w Cast Aluminum Car Subwoofers Sub Woofers | eBay
I can always put both in and have the two 10"'s for loud bass and the two 6x9's for midbass and bass.
I can always put both in and have the two 10"'s for loud bass and the two 6x9's for midbass and bass.
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Hi VenusFly,
The woofers in the parcel shelf will not give you deep bass because the "box" they are in is leaky. Tried and went back to a sub box. In a sedan without fold down seats, it works a little better. Still, a real box with woofers works better.
You could consider using a pair of 8" woofers in the dual 10" box. Given the right woofers for that size, you might get down into the 35 Hz region (-3 dB), which is extremely low compared to what you have. Note that most manufacturers quote speaker response at the - 10 dB points.
-Chris
The woofers in the parcel shelf will not give you deep bass because the "box" they are in is leaky. Tried and went back to a sub box. In a sedan without fold down seats, it works a little better. Still, a real box with woofers works better.
You could consider using a pair of 8" woofers in the dual 10" box. Given the right woofers for that size, you might get down into the 35 Hz region (-3 dB), which is extremely low compared to what you have. Note that most manufacturers quote speaker response at the - 10 dB points.
-Chris
Hi Perry,
What frequencies does cabin gain operate over? I know when we installed boxes that did go right down to 30 ish Hz flat, they sounded a lot better than systems that depended on cabin gain.
-Chris
What frequencies does cabin gain operate over? I know when we installed boxes that did go right down to 30 ish Hz flat, they sounded a lot better than systems that depended on cabin gain.
-Chris
Too much cabin gain can make it difficult to get good, accurate sound but for systems that are essentially one-note-wonders, it can make them seem strong. The following is one example of cabin gain but it will vary greatly by vehicle.
http://www.bcae1.com/images/gifs/leap07.gif
http://www.bcae1.com/images/gifs/leap07.gif
Hi Perry,
I imagine you could EQ the bass response to take into account of cabin gain on a per vehicle basis. You have an advantage here as you would have a feel for this seeing the car.
-Chris
That's what I was thinking.
I imagine you could EQ the bass response to take into account of cabin gain on a per vehicle basis. You have an advantage here as you would have a feel for this seeing the car.
-Chris
Here is what I have to work with: (in the last pic notice the metal brackets, I can put a piece of MDF on there and mount my amp up underneath the rear parcel shelf.) The dual 10" sub can then fit right underneath it. I want to remove all of the carpet first though and add sound deadening material to the entire boot.
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You're in 8" territory with that size. By that, I mean that using the optimal box size for the drivers, you have enough room for a pair of 8" drivers. Before groaning that they are too small, understand that some will in fact get you down to around 35 Hz -3dB without cabin gain. They will be more efficient meaning you need less power to feel the tunes.
The best car I ever did used Peerless 8" woofers. It had the highest sound quality and went louder than most other speaker systems within range, like the 10" and 12" drivers. Using the same drivers I had a B2200 truck that took sound quality and SPL contests for at least 1/2 the summer without changes. The owner then tried the same thing with 10" drivers and basically it all fell apart. Not too bad for a home speaker that wasn't known for it's efficiency.
If you get a chance, use some speaker box programs and play before building anything. Prove what I am telling you. They may have special drivers these days that change the tables, but at least you will be picking the correct drivers and getting the best bang for your dollar - with no regrets. Speakers can be wildly different as to what box they need. You need to choose with knowledge instead of what someone wants to sell you.
-Chris
The best car I ever did used Peerless 8" woofers. It had the highest sound quality and went louder than most other speaker systems within range, like the 10" and 12" drivers. Using the same drivers I had a B2200 truck that took sound quality and SPL contests for at least 1/2 the summer without changes. The owner then tried the same thing with 10" drivers and basically it all fell apart. Not too bad for a home speaker that wasn't known for it's efficiency.
If you get a chance, use some speaker box programs and play before building anything. Prove what I am telling you. They may have special drivers these days that change the tables, but at least you will be picking the correct drivers and getting the best bang for your dollar - with no regrets. Speakers can be wildly different as to what box they need. You need to choose with knowledge instead of what someone wants to sell you.
-Chris
Ok.
I'm going to tackle two 8" drivers with this program: Sonosub - Free Speaker Design Software
It only does ported subs tho. So the search continues.
AJ Audio Subwoofer Box Enclosure Design Software - Sub Speaker Cabinet Building Program Downloads
Going to try ajsealed.exe
I'm going to tackle two 8" drivers with this program: Sonosub - Free Speaker Design Software
It only does ported subs tho. So the search continues.
AJ Audio Subwoofer Box Enclosure Design Software - Sub Speaker Cabinet Building Program Downloads
Going to try ajsealed.exe
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Found some moderatley-expensive but not out of reason 8" drivers: Alpine SWR-8D4 Type-R 8" Subwoofer | eBay
If I were to import some cheap Peerless drivers from the US they would cost about the same when shipping is included.
Here is the specs sheet: http://support.alpine-usa.com/products/documents/OM_SWR-8D2_8D4_EN.pdf
Here is the info for the box size diameter from the AJ Sealed designer: (I have no idea what I'm looking at)
If I were to import some cheap Peerless drivers from the US they would cost about the same when shipping is included.
Here is the specs sheet: http://support.alpine-usa.com/products/documents/OM_SWR-8D2_8D4_EN.pdf
Here is the info for the box size diameter from the AJ Sealed designer: (I have no idea what I'm looking at)
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