Amp choices and wiring questions

[Ru Dawg]

OK, I'm pretty much settled on a Q-logic bandpass box and 2 12" Infinity Perfects.

First questions is if I wire the subs in parallel to create a 2 ohm load, then the total RMS power I can feed them will be the sum of each sub (350+350) which is 700watts RMS....correct?

Second, the closest amp I can find to get 700 watts @ 2 ohms is an Audiobahn which puts out 600 @ 2ohms...is this enough or will it under power this setup.

Third, if a 2 channel amp is rated at 350watts bridged @ 4 ohms...would that make it 700watts bridged @ 2 ohms?

Am I making any sense???????????? LOL!!!

Also...what about the Perfects...any better suggestions?

 

[KeyserSoze]

1. If you wire the subs together in parallel, you are correct that you can give them 700 watts total.

2. Using that audiobahn amp will not hurt your subs as long as you keep the subs from distorting. You could also go with more than 700 watts. Many people have been giving their perfect pair 1200 watts. That may be a little extreme but if you go to 800 you will probably be ok.

3. The amp might make twice as much power @ 2 ohms than 4 but not necessarily. You would need to check them specs on the amp to find that out for sure, or check with the manufacturer. You might also want to check to make sure that the amp you get can support a 2 ohm load.

The perfects are good subs, just use common sense, and they will last a long time.

 

[aerialist001]

Good questions. I don't have a clear answer for you but I will tell you what I do know. I have to perfect 10's (sound great) with an ifinity beta digital 100 amp. The amp is 2-ohm stable. This is where it gets interesting: You are correct that when you wire your speakers in parallel the load will be 2 ohms. However when you have a two channel amp and are using it in bridged mode the amp sees only half the resistive load, or 1 ohm. The amp is not stable at 1 ohm and will (I did it) shut down via it's over current protection ciruitry. To solve this I had to wire my speakers in series giving them an 8 ohm load, then the amp saw only 4 as I am using it in bridged mode. So I am not sure if the speakers are getting 100 watts each or 200 each because although the amp is in bridged mode I beleive your power is only doubled if it sees a 2 ohm load. This is impossible to achive with two speakers. As a note, this is not a huge amp, but the perfects are extremely efficient (high dB output even at lower power levels) and sound amazing on this amp. The only way your amp can see a 2 ohm load in bridged mode is with a single 4 ohm speaker (or a pair of speakers wired in parallel in series with another pair of speakers wired in parallel...). So in conclusion if you are looking for max power I would suggest buying two amps, one for each sub no more than 300 watts each bridged at 2 ohms. So (2) 150x2 bridgeable amps would provide plenty of power to rattle all the nuts and bolts out of your car. (To eliminate the hatchback rattle that you will have see my response to the "rear hatch rattles" post.)

Hope this helps,
Todd

 

[leenjen]

if the Audiobahn amp is rated at 600 watts, it will put out much more. my Audiobahn A275HC with an ACAP2 puts out over 1000 watts RMS. and it is rated at 600 watts @1ohm.

as far as bandpass goes, you will get a very narrow frequency range. a ported box will give you much better sound while providing plenty of SPL. you could just buy a large sealed box and port it yourself.

 

[Brian's98XLT]

If you are going to run alot of power I would recommend a small sealed box for them . Infinity recommends a 1 cubic foot sealed box for them, so you would want a type 1 Q-logic box.
As far as running a amp 2 ohms bridged make sure it is stable at that rating. I would recommend a mono amp for your subs. Rockford, MTX, Kenwood or Alpine all make some nice mono sub amps that will run 2 ohms all day without a problem. The problem with bridging a amp is that your damping factor goes down and the distortion goes up. Which usually ends up in crappy sounding bass.

 

[ExploreThis95]

The Infinty 12" Perfects should be put into a sealed enclosure with 1.25 of air space. The 1.0 that Infinity recommends is not enough. I have tried both enclosures and noticed a tremendous amount of difference in the quality of the sound. I am also using the Rockford Fosgate Power BD1000 which puts 500 wtts rms into each sub. You can never have too much power...just make sure you listen for distortion.

 

[mrsteve]

Please don't put those subs in a bandpass box. If you really want a bandpass box buy some cheap subs; you really won't notice a difference in the sound. If you really want the Perfects put they in a sealed or ported box.

Also there is such a thing as too much power. When you send so much power that the voice coil frys along with the rest of your sub, and smoke starts to come out from the port in your box you've got too much power. Many people say the Perfects will handle anything you can throw at them so some people are sending 1000 watts RMS to a single 12" thinking it'll sound even better with that power. Once you send the sub enough power so that it reaches it's full excursion you don't need to send anymore. All it really will do is cause heat.

Steve

 

[JTang]

As with the above posts, you'd be absolutely wasting your time and money putting high end subs in a bandpass box. High end subs are meant to play high end, accurate *tight* bass, or at least the ones you are purchasing. The whole design of a bandpass box is to manipulate the sound in an echoing chamber till the waves hit the right frequency to escape from the ports, hence the echoey booming rumble of bandpass. All you'd be doing is killing the very intent of the Infinitys. If you really want bandpass, you just need a sub with long excursion that can take a lot of abuse, but don't need to spend the extra cash on accurate reproduction.