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Well I woke up this morning to find the second replacement driver sitting on my door step... that was nice. I called and talked to JC about the phase issue I'm having and asked if the 800 was designed to be 'in-phase' or 'out-of-phase', and surprisingly, he didn't know right off hand. So he said he would talk to Tom and get the right answer from him.

I know when I push one speaker in the other pushes out. But that's what it should do as it is a sealed enclosure (and air tight at that!). Pushing the one cone in displaces the air pushing the other cone out. So if that's the case, could they work in-phase in a sealed enclosure??? If it's air tight it wouldn't seem like they could work together going in and out at the same time... could they???

Anyhow, pray for me and my EP800!!!




P.S. (I was playing a wide variety of music this morning watching the cones to see if it's just a trick of the eye making it look like they're out of phase, or what. After close observation I can definately say that they are out of phase! They simply do not move in and out at the same time together).

The volume of the 800 is enough that the pressure inside the box will change when both drivers are pushed out or pulled in.

Ported boxes can be smaller, and play louder because you can hear the back pressure wave from the cone.

Sealed boxes need to be larger so there enough volume of air to be easily compressed, but can be more punchy because the air acts as a spring.

So yeah, pushing one cone in will make the other move out as the box will try to maintain the same volume. But when they both are being driven there's enough energy from the amp to slightly compress or decompress the enclosure.

Of course all that is assuming both speakers are supposed to be in phase. I think they really should with how close they are to each other there would be a lot of cancellation if they were running out of phase. But I'm only an armchair speaker designer.

That was pretty much what I was thinking.

Micah,

The woofers in the EP800 and all conventional speakers operate in phase, whether or not it's a sealed or a ported system. If the two EP800 woofers were out of phase, there would be zero output, or virtually that.

Since you have installed a replacement woofer and amplifier yourself, you might have inadvertently reversed the connections to one woofer.

I'm sure you've already spoken to JC, but for the benefit of others, I'll post Ian's method of verifying if woofers are in or out of phase:

"If you want to check that you got the woofer installed correctly, remove the amp and disconnect the speaker wires from the back of the amp. Using a 9-volt battery, touch the speaker wires to the battery posts following positive to positive and negative to negative. Hold the wires to the battery connection. Both woofers should move out and stay there. If one moves out and one moves in and they stay there then the one moving inwards is out of phase. If one cone moves out and one moves in but returns quickly to the centre position then that woofer is not working at all."

You won't damage the woofers using a 9-volt battery.

Regards,
Alan

One other thing, Micah:

If one of the woofers in the EP800 cabinet wasn't working, it would appear to be operating out of phase because of the air pressure in the cabinet from the working woofer. In other words, as the working woofer cone moved inwards, the non-working woofer cone would move outwards.

Alan

Yes I just talked to JC & he was going to send me that test via email. I will try that out tonight. If they are indeed in-phase then looks can definately be deceiving!!! Because looking at them from a multitude of different angles while they were really working hard, my fiancee & I both thought they seemed to be working opposite of eachother.

But the test should tell us if that's the case or not.

(bury's face in hands)...



Well, it's still there.


Installed the second new woofer, played it all day long (played it fairly low for the first few hours. Second few hours turned it up to about -20, then I started to push it a bit harder) with music, sounded great. After putting a good 7 hours of playing time on it, I gave it a break. Then I put in 'Iron Man' (my reference LFE DVD) and started to play the cave scene... the crackling sound is still there, and I might add, it actually sounds a bit worse with the new driver... WTF??????

Ok, time for the phase test. Could they have sent this big guy to me with the speakers out of phase??? It seems highly unlikely, the bigger question in my mind is, are they both playing, or is there a bad connection allowing only one to play? The single driven cone would move the undriven cone with the moving air inside the box, creating the appearance of two drivers running out of phase.

I shall conduct the test immediatelly. If they are indeed out of phase I will be shocked. If only one driver is being pushed, then I think it's time to box this guy up and ship it back to be replaced with a new unit. I think I've exhausted my ability to troubleshoot the problem. Time to see if another unit exhibits the same 'popping' sound as mine does. I would love it if SRoode would make his way east to check this out with me. Perhaps bring one of his 800's along to see if I can get his to do the same thing, or if his would just blow mine away!!!

That would be interesting!

You sure have more patience than I do, that sucker would have been sent back by now. I am surprised how much I have read on problems with their subs. For what's out there in the 800s price range you could get a whole lot of sub (subs) for less, I'm sure.

It might be worth it to return it/refund it so Axiom can run this sub through some testing. It would ultimately benefit both parties in the long run.

I would agree with that Doc. Micah, you've shown a lot of patience but it's not really you're problem to fix(great if it's a simple fix...but) and as Doc points out, it should be tested at the factory.