bipole/dipole working correctly?

The problem is that your post is confusing. First, it would help if you posted the brand and model of speakers. Second, I don't know what you mean when you say "outward" and "inward". Bipole and dipole surround speakers (are you even asking about surround speakers?) have drivers that face to the sides - is that what you mean by outward? Real bi- and dipole speakers will not have drivers facing you (inward?) but often times they're not 100% dipoles and have a mono bass driver facing inward. Is that what you are referring to?

Ed

Take the two speakers and switch their positions on the wall. Put the left speaker where the right one is mounted and put the right one where the left one is now. Don't change the orientation of the drivers.

Reason? If they are truly dipoles, you may be creating a null in the center if you have 180 degree out of phase waves propagating towards each other. By changing left/right placement, you would reverse that effect and have in phase signals reinforcing each other and the sound should be dramatically different (louder). The out of phase half of the dipole would then be bouncing off your side walls and creating a sense of diffuse sound.

If your Polks are truly bipoles, reversing them should have no impact as the signals coming out of both sides will always be in phase give or take the arrival time at your ears. If you are seated equidistant from the left & right speakers phase differences should be nil.

Be aware that surround channels are not constantly active in either movies or multichannel music. In fact they are not active much of the time and when they are they may be handling sounds that are much lower in level than the main L/R channels or the center channel. The best way to test a multichannel level trim is with a white noise signal built into virtually every multi channel receiver and pre-amp.

Something obvious. Are the speakers fused? Is there a blown fuse or circuit breaker?

How do you have the trim set for the surrounds relative to the front and center channels? Turn on the test signal (aka white noise generator) on your receiver or preamp. Cycle through each speaker. Do the levels sound similar subjectively? If not, check the trim (level) in your reciever's setup routine.

If you haven't got them out of phase and it's not a trim problem and fuses aren't blown, check the speakers and amp channels by taking the surrounds and hooking them up to the front outputs for a minute. If they sound more lively, it's not the speakers. It may be the rear channel amps. Now take your front speakers and hook them up to the surround channels for a minute. Do they seem to have the same problem as your surrounds? More evidence that something is amiss with the surround channels other than your speakers.

Are the speaker wire connections for the surrounds well terminated and solidly attached on both ends? How long a run of wire did you use for the surrounds and what is the gauge of the wire? I use 12 gauge wire for all connections because it's pretty much an all purpose solution unless you have a really long run. A long run with light gauge wire may increase resistance to the point that your receiver can't deliver enough current to power the speakers effectively. Solution? Get a bigger pipe/wire.

Dipole: one driver sucks while the other driver blows

At the center line, between the two drivers, the sounds cancel each other and you have a null. Although I don't like dipoles at all

for home theater, this would be the configuration that THX recommends for SIDE surrounds.
Bipole: both drivers suck or blow at the same time

At the center line, between the two drivers, the sound is reinforced instead of cancelled and the net result

(in a properly designed unit) is a hemispherical soundfield, equal in all directions. This would be the proper setting for REAR surrounds. Even THX recommends this for Dolby 7.1. (This is also the configuration *I* would use for SIDE surrounds and is also the Dolby recommendation!)

In a surround application you're right but there are planar dipoles like Magnepan and Martin Logan that do indeed point one side of the dipole output directly at the listener and reflect the 180 degree out of phase back wave off the room boundaries behind the speaker. I use Maggie 3.6's as my main speakers in a 7.1 channel setup and I love em.

Yes, I realize that - in fact, that's why I added the question in parentheses about whether the OP is talking about surround speakers.

Ed

I think that they should be the same volume. Sounds like the speakers are broken or defective.

Ed

Say what?

The Polk LSiFX is a strange design. I have never seen a dipole/bipole like it

Usually one set of drivers are direct radiating (meaning, pointing at the listeneres head) These don't appear to be setup this way.

What you're describing is a bipole where both waves are generated in phase. Bipoles can be placed in either the left or right position since they are exactly the same.

A dipole on the other hand generates two waves that are 180 degrees out of phase and a null 90 degrees off axis where the out of phase waves meet. Dipole surrounds are mirror image pairs that have a specified left and right placement. So, if you aim two out of phase waves at each other and you're situated equidistant from the two sources, you've likely just generated a null where the waves meet which also happens to be where you're sitting. By reversing the speaker positions, you might put two drivers that are in phase facing towards the listener as intended by the dipole design. Assuming you had it reversed in the first place.

Since the OP specified these are mounted on the rear wall with one side facing the listener, the dipole phasing issue may be the problem. If they were on side walls, it wouldn't be as much of a problem.

You're right there. I had a morning brain lapse. :-D I already deleted it before your post when I realized my mistake. I knew better than that. I knew they had to be 180 out of phase, but reversed the image in my head when I typed it out.

But I still didn't understand your previous post. Although from what I understand these Polk LSiF/X do have a left/right side labeled on the back of them near the serial number. Like I said, I never seen a setup like this before. Its unconventional for a dipole/bipole mixed design.

Only the speakers pointing directly at the listeners head should be firing in bipole mode.

I would imagine all speakers would fire in dipole mode.

Not really unusual. These Polks are not the first dynamic driver, box surround speakers to offer both. There's usually a simple switch built into such a design that allows you to flip the phase on one set of drivers in each box 180 degrees to create a bipole or dipole as you wish. Once set to dipole mode, you just have to make sure you've got them mirrored correctly to avoid nulls.

I wish I knew how to upload a sketch. You'd get it instantly from a picture.

Planar speakers like my Maggies on the other hand are natural dipoles. When the front side is generating positive pressure the back side must generate negative pressure and vice versa. Dipoles can be very useful in a real world room. The back wave can provide a sense of space with 2 channel material and the nulls at the left and right side can minimize room boundary interactions with adjacent walls.

Definitive Technology has made a living out of bipole only main L/R box speakers with dynamic drivers as have many other speaker companies dating back to at least the 70's.

And then there's surrounds like mine that don't fit any of these categories but are also set up as a mirror image pair. But I'm too lazy to go into that description.

It's hard to imagine a setup issue causing this behavior in a surround speaker. And if the speaker demonstrates the same behavior in your rear channel, your front channel, and the store's setup, it's a safe bet there is something wrong with the speaker.

Don't be put off unconventional radiation patterns because of a defect in one sample of one product. Dipoles and bipoles can be very useful in some situations.

Happy hunting!

I can't say that I have personally heard the polk LSiFX but looking at them physically I would say they are a poor design for a bipole/dipole mix.

Bipoles should directly radiate to the sides of the ear. With the angled speakers of the LSiFX, even directly pointed at the head, you would be hitting the rear outside of the ear at a steep angle. This will cause roll off in the upper frequencies.

Most dedicated bipole bipole mixed speakers have a center firing high frequency driver which points at the side of the head, not the rear quarter. This is why I said the polks are an unconventional design.

I never liked mixed designs. bipoles should be at ear level, dipoles 1->2 feet above. It's really a sub optimal solution even for those with dedicated bipole drivers in the center firing at the sides of the heads.

I googled the speakers, and one thing I noticed is that they are not only Bi/Di Pole switcheable, but Bi-Wire able. I was wondering if the straps connecting the upper and lower portions of the x-over were all tightened properly. It could also easliy have been that the Bi/Di Pole selection switch was bad. Good luck with your next set of speakers.