Rep Power: 0

I have a 12" rockford rfp4212 sub which is in a bandpass box right now. I was reading up on subs and enclosures and i was wondering if i should put it in a sealed or vented enclosure instead. I read that a sealed will sound clearer. If i change the box which one should i do sealed or vented, and should i just buy one or make it. Building it will be easy for me the only thing that will be hard for me is tunning a ported box.

Also i realized my sub isn't hooked up the way i thought it was and im wondering if the way it is hooked up is bad.

my amp is bridged 400x1 rms and 4ohms and my sub is daul voice coil and 4ohms x 2

the positive wire from the amp goes to the positive on one voice coil, and the negative from the amp goes to the negative on the opposite voice coil, and then the remaining two are connected by a wire. This setup is giving me a 8ohm load. Will that be ok with my amp

If i wire the positive on the amp to the both positives on the sub and the same with the negative it will give me a 2ohm load which is two low for my amp.

So what do i do should i only hook up one voice coil? Then it would be 4 ohm right?

 
Rep Power: 0

It is never recommended to run w/ just one voice coil of a sub.

You are right that its hooked up in series giving you an 8 ohm load. That makes the amp output around 275 watts instead of the full 400 watts. If you wire it in series so that you end up at 2 ohms chances are it will hurt the amplifier. Basically you have to live with it the way it is.

As far as a box, sealed is good. I have always gone sealed. Ported is good too. Ported boxes just have to be more exact. Port size and length are critical to the overall sound. Buying a ported box off ebay or something is a bad idea. In no way will the box be suited right for your sub. Generally building your own, or paying to have one built is the only option for a good ported box thats meant just for your sub.

Others on here can help come up w/ dimensions for a ported box.

 
Rep Power: 0

what happends if u run it in series, then bridge it on the amp?

 
Rep Power: 0

if i run it in series it will give me a 4ohm load, i just talked to a guy from rockford and he said to get a dvc 2ohm sub, that whay when i hook it up like i have mine now it will give me a 4 ohm load, then it will match my amp

So should i buy a new sub (dvc 20hm), or should i just leave it with the 8ohm load. I mean right now it sound pretty good, I would imagine it would be amazing if i take advantage of the whole amp.

Also is this a good sealed enclosure http://www.sounddomain.com/sku/RTE31612

And finally what does ohm mean, i mean how does it effect the sound?

 
Rep Power: 0

if u run parallel it will give you a 2 ohm load.
running series is what you have now, which is giving u an 8ohm load

then, bridge that to the amp, which should give you a 4ohm load

any techies wanna check to make sure this is right

OHM is the amount of resistance a speaker has. if an amp pushes (x) amount of power to a 4ohm speaker, with a 2 ohm speaker, the power will be doulbe, and with an 8ohm speaker, the power will be half.

this is a good site...i learned alot from it....it talks about the technical aspect of EVERYTHING audio.
http://www.bcae1.com/


as long as the box is made of strong wood (MDF, 3/4") is sealed up, is very solid, and matches the volume requied by your speaker....it should do the job
some insulation also helps as well.

 
Rep Power: 0

my amp is bridged and is giving me 4ohm

 
Rep Power: 0

so its hooked up properly then

 
Rep Power: 0

Sorry i confused series and parallel before.

Yes its hooked up correctly, however my amp is at 4 ohms and my sub is at 8 ohms. So im not doing any harm but im also not taking advantage of my amp, because instead of 400w rms, i am only drawing 200w rms now. So to fix the problem i will have to get a Rockford HE2 RFP4112 (which is dual voice coil at 2 ohms) So when i hook it up in series i will get 4ohm which will match my amp. Plus my amp is 400w rms 800w peak, and that is the rating of the above sub, so it should be a perfect match.

Now for one of the original question, what should i do about the box?

 
Rep Power: 0

Not to be an *** but lets be correct in how we say things.

The sub is dual 4 ohm. Wire it in series and it acts as an 8 ohm sub, in parallel it acts like a 2 ohm sub.

The amp is 4 ohm stable. The amp isn't any ohm, it just needs 4 ohms to be able to output the most wattage. It isn't 2 ohm stable when bridged, and therefor it can't be used when the sub is wired in series at a 2 ohm load. This would cause the amp to draw more current and output more power than it was designed to. This would most likely send the amp into thermal protection.

However when used as an 8 ohm speaker the amp is fine. All the 8 ohm means is that its harder to push the speaker. This makes the amp use less current and output less power.

Powerwise nothing is perfect. From 4 ohms to 8 ohms isn't really going to make the amp put out half the power. More than likely it will put out about 275 rms and 550 max. Not the perfect 400/800 that it could put out w/ a 4 ohm sub.

If you want, yes a dual 2 ohm sub, wired in series for a 4 ohm load, would make the amp work to its full potential. But the difference in sound wouldn't be very noticable. It takes double the power to achieve a 3db gain. So your sub will only likely be down a couple db.

Personally I'd make a custom ported box. It will make the sub sound a lot better. I assume the bandpass box is prefab. Prefab boxes are just a bad idea all the way around. Don't buy prefab bandpass or ported boxes. Have one custom made just perfect for your sub. You will like the results.

 
Rep Power: 0

should i make my own box or should i get one made, and where can i get one done in nj

 
Rep Power: 0

Any stereo shop should make a box for about $100 to $150.