Coffee table sub????? (1 Viewer)

[Chris:-/OV]

Hi
These holidays I'm planning on building a coffee table sub. It's gonna be about 600(litres) and I want it to go down to 15Hz. I'm planning everything on WinISD but I was wondering if the plot should be smooth, flat or what?
I want to use it for movies to get a hell of a lot of bass out of them but I listen to hip-hop aswell so it should be able to shake the room. I have a neighbour who is very smart with speakers and speaker building but he's busy most of the time so I need help from you guys.
So should the plot be flat or can it have a bump at about 40Hz for the hip-hop music's bass to stand out or will this bump have a bad effect on movies?
I wanna put in 2 ports but I see that when i enter that I've got 2 ports into WinISD then the ports suddenly become longer even though there are more of them now?
Thanks
Chris

 

[Owen Bartley]

A flat response is generally more desirable for music and movies. Remember, you can always juice the bass on your receiver for boost. And if you're building a 600L sub I wouldn't worry about lack of bass, my ~210L Tempest shakes the whole house with movies AND music. What are you using for drivers? Amp? Its gotta be pretty serious in a box that big...

 

[TimForman]

Its gotta be pretty serious in a box that big...

Did you really mean 600 liters? That's not a coffee table that's a coffin! Actually it works out to about 142x68x60 cm internal.

 

[Chris:-/OV]

Hi
Yup its gonna be 600 LITRES. I want all the bass i can get. I have'nt chosen drivers for it yet but what do you guys think? 2 12" or 2 15"? What specs on the drivers should I look out for? .eg. Should the driver have a high SPL and XmaX?
Another question: So for car sub you would want a bump in the frequency at about 40Hz for the thumping bass?

 

[Andrew Pratt]

Chris you need to pick the driver(s) first then design the box/porting for ir (them). What drivers are avaiable to you?

 

[TimForman]

He may need to do both. A piece of furniture is expected to be a certain size but the particular driver(s) will need a certain volume. Shooting from the hip, two Tempests would work. Do you have access to something equivalent? Another alternative is to put tubes (Sonotube) inside the enclosure to achieve the correct volume or use baffles in a quarter-wave design like the old

Fried design.

 

[Chris:-/OV]

Hi
I can't get hold of any drivers for home use except for Celestion 12" drivers (model no: G12k-85) and tons of car subs (almost all of them except for Adire)
You guys say I can only start building the enclosure once I have the drivers but can't I build it so long because all that needs to be adjusted later is the port lengh?
Thanks
Chris

 

[Chris:-/OV]

Hi
Update:
I just found out that the Celestion drivers are used for guitar subs.(this model) but would it still be appropriate for the enclosure I want to build? (for home theater)
Chris

 

[Chris:-/OV]

Here's some specs on it:

Model:The G12K-85 Size:12” Power:85 Sens:99 Freq Hz:80-5.5k Use:Tight responsive sound Inc Vat:£53.00

Chris

 

[TimForman]

I just found out that the Celestion drivers are used for guitar subs.(this model) but would it still be appropriate for the enclosure I want to build? (for home theater)

I doubt it. Judging just on the measurements you provided (Fs=80) it will not go very low. Can you order something?
If you're not able to get a home audio sub driver you may have to go with a car sub. This will generally require a smaller cabinet but not necessarily. If you can get someone to provide you with the minimal parameters of the driver we can probably get you started. Unless you're really into trial and error.

 

[Chris:-/OV]

Hi
I'll get specs of a few car drivers that are available to me but what specs should I look at eg. should the fs be low, high, should the spl be high or low, should the xmax be high? etc.
Which brands would you recommend? Pioneer, Kenwood, Infinity, JBL, Earthquake, JL Audio, Sony, Hertz, Jamo? (These are some of the brands available to me)
Seeing that the box size reduces with car drivers should I also then rather get 15" drivers?
Will I still be able to get low frequency response down to 17Hz or so with car subs?
Thanks with the help
Chris

 

[TimForman]

Will I still be able to get low frequency response down to 17Hz or so with car subs?

That will be a challenge. Car subs in general are not designed to go that low, especially in a room. They are usually designed with the thought that they will be in a small space and benefit from cabin gain.

 

[Chris:-/OV]

Hi
Are there any other specs I should look out for?
Will I be able to use a car amp hooked up with a step down transformer because plate amps are very expensive and rare here in South Africa.
Thanks
Chris

 

[TimForman]

Will I be able to use a car amp hooked up with a step down transformer because plate amps are very expensive and rare here in South Africa.

I don't know why not.