First sub enclosure build design - will it work?

[Blimsters]

Hi there,

I'm new to the forum, and pretty much new to car audio. I've done a few basic installations in the past (replacing speakers, head units, wiring in amps etc), but I wouldn't say I've 'designed' a system before and have certainly never ventured into any of the theory of it. I've decided to put a bit more effort into improving the sound in a recently purchased car (2006 Alfa Romeo 159), including building a subwoofer enclosure. I'll outline my plans below, and if anyone has any feedback or suggestions they would be very welcome, mainly I would like to know if there are any major issues with it that I'm unaware of, since as I mentioned I'm new to the theory and design side of it.

I'm taking a fairly low-power budget approach, but would would still obviously like it to sound as good as possible. I've ordered a JL Audio 10W0v3-4 10" 4ohm woofer and am leaning towards pairing it with a Kicker Key 500.1 amp, it's compact size putting it ahead of other options with similar features and outputs. For the box, I'm trying to go for a ported enclosure that's as compact as possible, and allows for a bit of experimentation with positioning. It's also pretty basic in terms of construction for ease of making.

Other design considerations include:

• The front and back of the box are both inclined at 14 degrees, which is the angle of the back of my rear seats. This gives the option of positioning the speaker facing either towards or away from the seats, possibly with the ski hatch open.
• The end panels protrude out at the front (as well as the bottom and rear) by about 2" to also allow for the option of a down-firing orientation, and the gaps created allow for air flow under and around the box, which I figure may affect the sound if the ski-hatch is open. The space on the rear also provides the option of mounting the amp there. The slight inclines on the bottom of the end panels is to allow for the shape of my boot.

Specs of the design: (I based the volume and tuning frequency on JL Audio's product page - https://www.jlaudio.com/products/10w0v3-4-car-audio-w0v3-subwoofers-92165 - others figured out with a bit of maths and SubBox)

• Enclosure internal volume: 32.5 litres (factoring in port and speaker displacement)
• Port area: 80cm^2 (4cm height)
• Total port length: 72.5cm
• Tuning frequency: 30Hz

I'm sure there are more optimal approaches, but I've tried to work with the practicalities and flexibility mentioned above. I've added some pictures of the design below. The fourth image is a variation that's taller and shallower, but the same principle.

Thanks for reading, any comments or suggestions welcome.

Click to read more...

 

[Buck 5,000+ posts]

What’s the vehicle, where is the box location going to be in the vehicle, and what kind of music are you listening to/what response do you want?

 

[Blimsters]

What’s the vehicle, where is the box location going to be in the vehicle, and what kind of music are you listening to/what response do you want?

Thanks for the very quick response. It'll be going in the boot of a 2006 Alfa Romeo 159 hatchback saloon without rear folding seats, so aside from the ski hatch the boot is pretty much sealed from the cabin. I listen to mainly electronic music, a variety of genres, but I'm more interested in deep bass rather than it being 'punchy', and much more bothered about clarity and sound quality than volume. I do realise that a larger speaker and enclosure would perhaps be preferable for this, but I still want use of most of my boot so after a fair bit of research I'm hoping I'm arriving at a reasonable compromise.

 

[Buck 5,000+ posts]

Thanks for the very quick response. It'll be going in the boot of a 2006 Alfa Romeo 159 hatchback saloon without rear folding seats, so aside from the ski hatch the boot is pretty much sealed from the cabin. I listen to mainly electronic music, a variety of genres, but I'm more interested in deep bass rather than it being 'punchy', and much more bothered about clarity and sound quality than volume. I do realise that a larger speaker and enclosure would perhaps be preferable for this, but I still want use of most of my boot so after a fair bit of research I'm hoping I'm arriving at a reasonable compromise.

You seem to have a fairly good grasp on what you're doing. I listen to a lot of electronic; 30 hz will be a great tuning to emphasize lows and smooth out the response.

Tell me what frequency bandwidth you want, like 25-60 hz, 30-80 hz, and convert your box specs for this dumb American into inches and cubic feet to make it easy for me, and I'll tell you what I think. It sounds like you're very close to where you want to be.

 

[Blimsters]

You seem to have a fairly good grasp on what you're doing. I listen to a lot of electronic; 30 hz will be a great tuning to emphasize lows and smooth out the response.

Tell me what frequency bandwidth you want, like 25-60 hz, 30-80 hz, and convert your box specs for this dumb American into inches and cubic feet to make it easy for me, and I'll tell you what I think. It sounds like you're very close to where you want to be.

Thanks for the comments, that's reassuring.

Whenever I'm testing out some new speakers or headphones, some of the first albums to go on are things like Panda Dub - Shapes and Shadows, Two Fingers - Stunt Rhythms, Tetra Hydro K - Labotomie, Drumspyder - The Mother Rune... I could go on, but anything from those will give you an idea. Basically stuff with a lot of sub-bass, so I'd like the subwoofer to be picking up the bottom end. The car actually had decent-sized door speakers as standard (6.75"), which I've upgraded to some that in theory have a response down to 40Hz, so they can do some of the work too.

We pick and choose our measurement systems over here (surely the only place in the world that dispenses fuel in litres and then measures its consumption in miles per gallon), so here's the 'corrected' specs:

• Enclosure internal volume: 1.15 ft^3 (factoring in port and speaker displacement)
• Port area: 12.4 (4cm height)
• Total port length: 28.5"
• Tuning frequency: 30Hz

 

[Buck 5,000+ posts]

Thanks for the comments, that's reassuring.

Whenever I'm testing out some new speakers or headphones, some of the first albums to go on are things like Panda Dub - Shapes and Shadows, Two Fingers - Stunt Rhythms, Tetra Hydro K - Labotomie, Drumspyder - The Mother Rune... I could go on, but anything from those will give you an idea. Basically stuff with a lot of sub-bass, so I'd like the subwoofer to be picking up the bottom end. The car actually had decent-sized door speakers as standard (6.75"), which I've upgraded to some that in theory have a response down to 40Hz, so they can do some of the work too.

We pick and choose our measurement systems over here (surely the only place in the world that dispenses fuel in litres and then measures its consumption in miles per gallon), so here's the 'corrected' specs:

• Enclosure internal volume: 1.15 ft^3 (factoring in port and speaker displacement)
• Port area: 12.4 (4cm height)
• Total port length: 28.5"
• Tuning frequency: 30Hz

Yeah, that seems fine to me.