I have 2 Alpine type R 12's. In a sealed box. I do not know if they are the 2 ohm or 4 ohm model. I am PRETTY sure they are DVC. My friend gave them to me and i don't know for sure. The back of the box has 2 red and 2 black outputs. One red and one black for each sub. I have no clue if they are wired at 4 ohms or 2 ohms and would like them wired at 2 ohms.
I want to make a ported box for them tuned at 32hz. If someone can tell me the dimension's of the box or lead me somewhere to figure them out.
After find out the dimensions and make the box i will take the subs out and find out if they are 4ohm or 2ohm and svc or dvc. and will need help wiring them at 2 ohms in the new ported box.
Well, each sub could be wired at 2 ohms, but the only overall impedance you can get is either 4 ohms or 1 ohm. This means you'd have to get either a 2 channel amp that puts out around 500RMS x 2 @ 2ohms, a mono amp that puts out around 1000RMS @ 4 ohms, or a mono amp that pushes out around 1000RMS @ 1 ohm. The cheapest route would most likely be getting a 1ohm stable amp such as the JVC KS-AR7501D or Polk PA1200. If you don't mind buying it refurbished you could also go with a RF Punch P1000-1bd from here. Or you can look elsewhere for a 1 ohm stable amp. As for port and slot vents, I think it's just a visual difference. Anyways, I don't think one has a benefit over the other. I'm not very good when it comes to building boxes, so I leave it to others come that department.
Would ajusting the length of a 6 inch or 4 inch pipe to equal the volume of the 5" pipe work instead of making the depth 14?
the volume of the 5" is 520.3262833
could i keep the 520.3262833 and have one 6" and make the length 9.2inchs.
That would keep the volumes the same
I just used a port calc,
would a 4" port at 6.95 inches
or a 6" port at 17.82 inches?
the problem would be getting the length that precise right. the only reason you added the 3/4" on the depth is to make the port easy to get the correct length.
mike b: Would ajusting the length of a 6 inch or 4 inch pipe to equal the volume of the 5" pipe work instead of making the depth 14? the volume of the 5" is 520.3262833 could i keep the 520.3262833 and have one 6" and make the length 9.2inchs. That would keep the volumes the same
Unfortunately for us all, that's not how port tuning works.
The volume of air inside the vent does not determine the tuning frequency. Larger ports must be longer to maintain the same tuning frequency, not shorter. At 9.2" length, the 6" port would tune your box to about 42hz. That's good for SPL, but the sound quality would be, well, bad. The good thing is that the larger port you use, the less noise the port will make.
If you want to maintain the first box size i suggested, use a 6" port with a length of 22 inches. The net volume would be reduced about 10%, but it's still within the volume range recommended by Alpine. Using a loose packing of Poly-fil would compensate for it, but you have to place it carefully around the port so it doesn't blow out of the box.
mike b: I just used a port calc, would a 4" port at 6.95 inches or a 6" port at 17.82 inches? the problem would be getting the length that precise right. the only reason you added the 3/4" on the depth is to make the port easy to get the correct length.
Your calculations aren't matching up to mine. Perhaps you are not deducting the volume of the port and subs... don't know. A single 4" port is not suitable for a pair of 12" subs. Don't drive yourself crazy trying to get the port to exactly the correct length. A half an inch off only represents a tuning shift of about half of 1hz.
I would have no problem adding that 3/4" and gettig the 6" at 18" long if i had that much left.. i already cut all the sides to correct length, i would have to get another sheet of MDF for 30 bucks when i am only adding 3/4 inch to one side. so i think i'll go with a 6" pipe 22" long, and add some poly fill. about the poly fill, only put it around the port?
mike b: I would have no problem adding that 3/4" and gettig the 6" at 18" long if i had that much left.. i already cut all the sides to correct length, i would have to get another sheet of MDF for 30 bucks when i am only adding 3/4 inch to one side. so i think i'll go with a 6" pipe 22" long, and add some poly fill. about the poly fill, only put it around the port?
On the contrary, place it in the corners of the box first and avoid having loose stuffing near the port. It's not necessary at all, so go without it until you're confident the subs are broken-in. Only use it after you've heard the box without it, so you can make a fair listening comparison. You may decide you prefer the box the way it is. It's not particularly well-suited for vented boxes, as it's difficult to keep it in place. An alternative is to staple 1" thick fiberglass to the walls of the enclosure, except for the subwoofer baffle(the wall the subs mount on).
Ok i will listen to it first, the subs are pretty far from new haha.
Is it a good idea to carpet the box? I read that you should put something between the sub and box (where you screw it on) and that carpet would be good.
Carpet makes a pretty lousy gasket. If the subs don't already have one, you can make your own easily enough with adhesive backed foam weather stripping. It's cheap and does a great job. If you do choose to carpet the box rather than paint it, cut away the carpet where the subs mounting ring attaches to the baffle. The way to do this and make it look nice is to carpet the whole box, put the sub in place, and then trace around the mounting ring with a box cutter or sharp knife, being careful not to damage the subs. Then you can lift the speakers out and pull up the excess ring of carpet.
Which amp would YOU choose?
Alpine pdx 1.1000
Rockford Fosgate Punch P1000-1bd
Hifonics BXI 1210D
ROCKFORD FOSGATE POWER T1000-1BD
Any input encouraged.
I'd choose the Hifonics, but then I'm the Clark Howard of the CF forums - i.e. I'm cheap.
I would say the T1000-1BD is the best quality of the bunch, the PDX is the most compact and stylish. I'd also look at the Sundown SAZ-1000.
Hope This Helps!!!
2002 Ford Focus Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs
Ok thanks!
I'm looking for a reliable amp that will make the type r's LOUD with good SQ! so far i have 2 votes on the rockford power amp... but that sundown looks pretty good for a good price.... idk about the quality of their amps though
mike b:idk about the quality of their amps though
I'd rate them higher than anything you are considering. One of our members had one and said they were actually stable to 0.75-ohms, but they didn't claim that officially. He also said they quoted power at 13.8V which is normal alternator output instead of 14.4 which is industry standard.
(I'm not sure they still do that, but I wouldn't worry about quality with them).
If i was to do 2 4" pipes what would the lengths be? thanks
mike b: If i was to do 2 4" pipes what would the lengths be? thanks
20.5 inches