I'm thinking about mounting my subs upside down. (With the basket facing away from the box, and the front of the sub facing towards the inside of the box.) Will I have to put the positive on the negative and the negative to the positive for the best sound? I've been doing research and got more confussed as I went along. If there is anyone that could help me I would appreciate it. Thanks

 

If im not mistaken dont subwoofers just make the sound "bmmm" and a lot of vibration, i dont think it matter where/how you mount it, and I dont think switching the wires is a good idea..


Watch some guy with real knowledge stomp all over me.

 

Well theirs a couple of factors. First, it doesnt matter it its "*** up" or normal, sound is the same. Now depending on if you have a 4ohm or 2 ohm sub , this than tells you your wiring possibilities. You would than want to buy a 1 ohm stable amp and wire the 4 ohm sub to 1 ohm. Here is how you would wire it.

 

All the two connections on any speaker do is establish phase. If you only have one subwoofer you can safely wire it either way, but one way may sound better than the other. Try both. There is no harm to the speaker or amp by hooking up the speaker "backwards" in this case.

Your instinct is right though. To maintain the same phase as if the speaker were mounted normally you'd reverse the connections if mounting the basket outside the enclosure.

 

Sorry, I shouda explained myself better. I have two Audiobahn subs that are Dual 4ohm. I made numerous phone calls and they said I should get a 2 channel amp and wire the amp with a 2ohm load for the best sound. I had a 1ohm stable amp picked out but I called Audiobahn and said it was too powerful and not nessescary. So is it safe to switch the wires if it's a dual 4ohm amp?

 

what kind of ****? too powerful at one ohm. probably cause its not rated to that ohm. Which means you should have gotten more capable speakers. What is the RMS on those? You should still be able to wire it anyway especially with two dual VC. Many possibilities. I bet you could wire it safely for 1 ohm. if the speakers are shitty than they will over work. If not then you will be pulling the most power out of your amp, which in my 17 year experience usually results in a better sound quality.

 

This is a dual 4 ohm speaker wired to present a 2 ohm load to the amp. You would do this for each speaker and connect each speaker to it's own channel on the amp. Ignore the "left" and "right" labels on this pic. Red is positive and black is negative.

 

A subwoofer, or any speaker for that matter has two functions: in and out. The polarity determines if the wave will start in or start out. Either way, it will make the same noise - but they all MUST be wired the same. If you have one wired normal, and one backwards, they will be out of phase, and sound really bad. multiple sub woofers mounted in the same box will cancel each other out if they are out of phase, as the peak and valley of the wave need to be seperated.

The main difference between "*** out" and normal mounted subwoofers is the volume. The closer to spec (on the theil/small sheet that came with the subs) you can get your enclosure, the better it will sound. Reverse mounted subs are most commonly mounted that way because they needed a little more volume to bring it up to spec.

 

Agreed.

Not always true. Phase establishes time. Speakers wired the same way are said to be in phase and a speaker wired backwards is said to be 180 degrees out of phase. Given a stereo pair of speakers you would never want one of those speakers wired out of phase from the other because they would have cancellation effects just as you described.

When we have a seperate subwoofer however we now have an additional source of sound that is in a different physical location from our main speakers. If there is a difference in distance from the listener's ear to the subwoofer and to the main speakers there can still be some cancellation and other ill effects at the listener's position due to time differences in the arrival of the wave fronts to your ears. You can alter time so to speak by reversing the phase on the sub or the main speakers. This will not effect how either sound by themselves, but it will effect how they sound together from your listening position.

A truly excellent subwoofer amplifier will have a **** that lets you adjust phase for exactly this reason. With speaker wires only you are limited to 0* or 180*. With a true phase adjustment you can typically set the phase from 0* to 90* and it can make all the difference. It all depends on the location of the speakers in relation to the ears of the listener.

 

If you are mounting two subs in reverse, which is sort of isobaric, you wouldn't need to reverse any phasing. If you mounted two speakers cone to cone, you'd need to reverse the phase on one speakers, so it would extrude when the other recedes. But since you are asking for a more basic installation, regular phase would work fine. Most two channel amps are 4-ohm or 2-ohm stable, so wire the subs to reach 2-ohm each. Dual 4-ohm subs can reach 2 or 4 ohms, and two of those wired up can reach a 1 ohm load (but that's only if you want to run a monoblock amp). Audiobahn also has specifications for sub enclosures using the method by which you mean to install your subs, I think they are on their website.

 

isoberic is SO hard to get right, but sounds great when you do.

 

depending on the style of surround on the sub, you might not get very good results if the surround hits the opening on the box, this could do damage to the surround.

whenever I mount a sub motor out, I use a mounting ring screwed in normally, and then mount the ring inside the box.

so you pretty much have to make a box around the sub... kinda a pain in the ***

and some subs make a lot of mechanical noise from the motor, which is usually baffled inside the box, beware of this

 

Alright thanks guys. I hooked everything up and it sounds good. Better than I was expecting. I did have to reverse the wires though, cause the normal way seemed like the subs were hitting a little late. Thanks for all the help.

 

Isobaric is incredibly easy to get right; there's no mystery to it at all. You figure out the volume required for a single driver then divide it in half if loading the enclosure with an isobaric pair.

The only true advantage to an isobaric setup is that you get to halve your enclosure volume. The downside is that you're running two drivers but only generating sound output from one. It's highly inefficient.

Where do you keep coming up with all these half baked theories?

 

Hey DamonB, what sounds better in a FD. A 10" or a 12"? I know their are many different variables but in terms of car space what is needed to achieve good sound and good bass. So i guess what im askin, is a 12" to much for the small space in an FD? And would a nice 10 get the job done?

 

It's really up to you. For me a single 10" is plenty in a small car, but for some it's not.

My home theater sub is a single 12" running on 250 watts and it will shake the house and play louder than I can stand for more than a couple minutes. Why anyone needs that much stuffed into a small car I can't grasp.

 

Ok, im gonna go with a 10" Alpine Type S then.

 

Isoberic is hard to get right, because the subs have to be sealed together pretty well, or it will sound bad. Isoberic sounds better because you get a tighter sound, more of a "thump", and it will be just as loud as if you did them both seperate.