Help! HT Sub Box Build & amp!

[Torgus]

this may be the wrong section but i thought you guys might have some ideas for me...

What box design should i design for these 12s?

I have 2 12'' RFR 1812 that are used.

http://www.fortunecity.com/sky....html <-- i assume these specs are correct.

Model RFR-1812
Description 12" Punch Power Woofer
Nominal Impedance 8 ohms
Re
(DC Resistance) 7.08 ohms
Power Handling
(RMS/Peak) 600/1200 W
Sensitivity 88.0 dB
Fs 27 Hz
QMS 3.24
QES 0.51
QTS 0.44
Sd
(Cone Area) 83.71 in2
Vas 3.5 ft3
Xmax 0.4 in
Voice Coil Diameter 4 in
Mounting Depth 5-19/32 in
(14.21 cm)

This is going to be a HT box.

I was thinking 7 cubes tuned to around 15hz? does that sound about right? or should it be around 20-25? also how large should the port be? any advantage to 1'' MDF? less box flexing? Should i make supports in the box as i'v seen other do to stop flexing?

Also i would need an amp to push them. does anyone have any suggestions? it looks like i need around 1200rms @ 4...everything i find online is over 1k for that much power. any ideas on a cheaper solution?

I'm hoping these will be extremely loud...thoughts?


oh and to finish the box i figured some textured dark grey spray paint and some rubber feet. i'd like to make the box into the coffee table but if i mount glass above it will it shake like crazy?

 

[Torgus]

I also toyed with the idea of a Dual-Reflex Bandpass. It would keep the woofers safe from damage that way...

anyways i think i foudn an amp for them:

http://www.zzounds.com/item--BEHEP4000

if i read it right that should be 700rms x2 at 8ohms right? and then 2k x1 @4ohms. which is good if i ever decide to pugrade to some nice fancy 15s. like maybe two FI Q 15s...

 

[lsiberian]

this may be the wrong section but i thought you guys might have some ideas for me...

What box design should i design for these 12s?

I have 2 12'' RFR 1812 that are used.

http://www.fortunecity.com/sky....html <-- i assume these specs are correct.

Model RFR-1812
Description 12" Punch Power Woofer
Nominal Impedance 8 ohms
Re
(DC Resistance) 7.08 ohms
Power Handling
(RMS/Peak) 600/1200 W
Sensitivity 88.0 dB
Fs 27 Hz
QMS 3.24
QES 0.51
QTS 0.44
Sd
(Cone Area) 83.71 in2
Vas 3.5 ft3
Xmax 0.4 in
Voice Coil Diameter 4 in
Mounting Depth 5-19/32 in
(14.21 cm)

This is going to be a HT box.

I was thinking 7 cubes tuned to around 15hz? does that sound about right? or should it be around 20-25? also how large should the port be? any advantage to 1'' MDF? less box flexing? Should i make supports in the box as i'v seen other do to stop flexing?

Also i would need an amp to push them. does anyone have any suggestions? it looks like i need around 1200rms @ 4...everything i find online is over 1k for that much power. any ideas on a cheaper solution?

I'm hoping these will be extremely loud...thoughts?


oh and to finish the box i figured some textured dark grey spray paint and some rubber feet. i'd like to make the box into the coffee table but if i mount glass above it will it shake like crazy?

Have you even designed the enclosure yet?

Let take it a step at a time. I'm sure TLS or someone could get you the proper size. After that you will want to design a box with proper bracing and venting. If you do it right you should end up with a pair of very impressive subs. Much better than any commercial sub.

There are two option for the box. You can use cabinet grade birch or ply. There is already a topic on this I started in the DIY area. It links to a longer discussion, but basically ply is lighter more rigid and considered less dangerous to work with from a lungs POV. You will still want to wear all the appropriate protection. Just read like crazy and you will find many of your answers.

 

[Torgus]

My enclosure should be rather simple. one vent on the side, nothing fancy.

So MDF isn't preferred? I come from a car audio background and basically everything is made out of MDF.

Have you even designed the enclosure yet?

Let take it a step at a time. I'm sure TLS or someone could get you the proper size. After that you will want to design a box with proper bracing and venting. If you do it right you should end up with a pair of very impressive subs. Much better than any commercial sub.

There are two option for the box. You can use cabinet grade birch or ply. There is already a topic on this I started in the DIY area. It links to a longer discussion, but basically ply is lighter more rigid and considered less dangerous to work with from a lungs POV. You will still want to wear all the appropriate protection. Just read like crazy and you will find many of your answers.

 

[annunaki]

I also toyed with the idea of a Dual-Reflex Bandpass. It would keep the woofers safe from damage that way...

anyways i think i foudn an amp for them:

http://www.zzounds.com/item--BEHEP4000

if i read it right that should be 700rms x2 at 8ohms right? and then 2k x1 @4ohms. which is good if i ever decide to pugrade to some nice fancy 15s. like maybe two FI Q 15s...

Band pass is very tricky to get right. It is actually easier to damage woofers due to distortion being masked with the woofer cone inside the enclosure completely.

The huge increase in size, to do it right; tune low with a wide enough acceptable bandwidth, also negates the use for the small gain in efficiency.

 

[annunaki]

My enclosure should be rather simple. one vent on the side, nothing fancy.

So MDF isn't preferred? I come from a car audio background and basically everything is made out of MDF.

MDF is plenty acceptable. It is cheaper, heavier, and does require a tad more bracing than 13 ply birch.

2-1/2 to 3 sheets of MDF can be had for the price of one sheet of 13 ply birch in my area. It makes the choice simple if one can deal with the trade offs.

I would not mind using birch if it was less expensive. I simply use more bracing and get the same or better results.

 

[annunaki]

this may be the wrong section but i thought you guys might have some ideas for me...

What box design should i design for these 12s?

I have 2 12'' RFR 1812 that are used.

http://www.fortunecity.com/sky....html <-- i assume these specs are correct.

Model RFR-1812
Description 12" Punch Power Woofer
Nominal Impedance 8 ohms
Re
(DC Resistance) 7.08 ohms
Power Handling
(RMS/Peak) 600/1200 W
Sensitivity 88.0 dB
Fs 27 Hz
QMS 3.24
QES 0.51
QTS 0.44
Sd
(Cone Area) 83.71 in2
Vas 3.5 ft3
Xmax 0.4 in
Voice Coil Diameter 4 in
Mounting Depth 5-19/32 in
(14.21 cm)

This is going to be a HT box.

I was thinking 7 cubes tuned to around 15hz? does that sound about right? or should it be around 20-25? also how large should the port be? any advantage to 1'' MDF? less box flexing? Should i make supports in the box as i'v seen other do to stop flexing?

Also i would need an amp to push them. does anyone have any suggestions? it looks like i need around 1200rms @ 4...everything i find online is over 1k for that much power. any ideas on a cheaper solution?

I'm hoping these will be extremely loud...thoughts?


oh and to finish the box i figured some textured dark grey spray paint and some rubber feet. i'd like to make the box into the coffee table but if i mount glass above it will it shake like crazy?

That is an old(er) sub, It is not real linear much past a few mm's for excursion as it has a fairly standard motor design. It will be best suited for a vented application.

I recognize the model number. I would suggest a single EP2500 at a minimum for those subs, they are not real efficient.

If I have time, I will try to model them for you.

 

[Torgus]

yes they are older subs. i got them for free for doing a FULL car audio install on a friend's g35. i was impressed with the specs when i read them. at 1st i figured they were really nothing special. but after doing some research i was happy with what i was given. i'v been told by many people that these we basically top of the line back in their day. i think when i get them running in the house it will sound awesome. If i do another build i'm going to use 15s or 18s most likely as you can't beat more cone area. after i tackle this i'm going to build some nice stereo speaker boxes. but i need to do more research before i figure out what speakers to use in em.

i'll def make a build thread for these subs. the second it's not cold i start working on them.

mdf it is!

i agree about the bandpass. i was looking into it but it seems like it's more work then it's worth. i'm going to use a simple hinge and make a front plat to protect the woofers. or a subwoofer grill. can't decide. http://www.parts-express.com//pe/showdetl.cfm?&Partnumber=260-440

 

[Torgus]

bizump!

so anyone have any comments on tuning to 15hz and making the box 7 cubed? good or bad?

i'v decided on 1'' MDF and a bit of bracing. should be enough so i can mount a pane of glass on top of the box with some spacers...

 

[annunaki]

These are a terrible choice for HT, no offense. They are an SPL type woofer designed for tuning in upwards of 30hz or higher. In a 7.0ft^3 enclosure tuned to 20hz they exceed xmax beginning at 52hz!!

Unless there is an error with the T/S parameters, they simply cannot be recommended for home use!

Sorry chap, better luck next time

 

[Torgus]

Thx for the info. What about using these in two stereo towers just for bumping the house stereo. I don't know what i'll use for the mids or tweeter yet but i have some ideas...say have them tuned down to to 35 hz? sound good?

i'll have to do some research on what the best cheapest 15 is. Ever modeled a 15'' Type R? they are cheap and take a beating...decent xmax if i remember correctly...

These are a terrible choice for HT, no offense. They are an SPL type woofer designed for tuning in upwards of 30hz or higher. In a 7.0ft^3 enclosure tuned to 20hz they exceed xmax beginning at 52hz!!

Unless there is an error with the T/S parameters, they simply cannot be recommended for home use!

Sorry chap, better luck next time

 

[annunaki]

I will have to model the sub again to see what the best enclosure would be.

The Alpine Type-R usually models fairly well. However, it does not play extremely low (if memory serves me correct), approx 26hz tune or so on the 12" was about as low as it could be tuned.

What type of budget would you be looking at for a 15" driver?

 

[Torgus]

$150 for each one give or take a few bucks.