I just received twin EP-350 V3 subs. They replace my older EP-175 and I'm using them with M22's and tube amplification.

They sound great. I had to set them up reverse phase (which I thought unusual, as they are set up next to my mains), this has been confirmed by low bass test tones.

My question is this: After I start a record or CD, the Subs wake-up and the pilot light goes green. However, the subs seem to take a minute or so to warm up and actually turn on. If I put my ear next to the driver, I can hear a faint mechanical noise. ??

I assume this is normal as both subs behave the same way. I can't imagine both behaving abnormally. Is a voice coil warming up? Is there enough voltage to wake up but not really get going? I can force them on it seems by raising the volume for a few seconds or using a small battery to the leads. With the old EP-175, once they went green, they were "on"

Anyone experience this?

Thanks

Dave

The noise your talking about is normal, my twin 350v3's do the same thing the first time they receive a signal. I think it will do this no matter if you have the auto-on feature enabled or not.

If your subs are up near your mains, you should use 0 phase, in fact, in most situations it is recommended to use 0 phase even if subs are placed around the room, I would not really on bass tests.

Hang on, hang on. This is at low volumes, correct? If you have the signal turned up when you turn on the receiver, does it still happen?

When you say a mechanical noise, if you stick your ear up next to it, does it sound like the signal's actually coming through, but it's several octaves too high and waaaaay too quiet?

How long does it take to go away?

I'm asking all this because I'll be shipping my EP350 back to Axiom shortly because of a problem like this (I don't think mine ever flips on if it's doing it, though), and I'd rather not waste their postage if it's normal!

Thanks Sirquack

Thats what I fiqured.

As far as the phase goes, I found it hard to believe as well. I double checked with the battery test (I look for the first initial transient movement of the cone). In both cases positive terminal of the battery to positive terminal at the back of the amp (with phase at zero) yielded backwards transient of the cone. Vice-versa when reversed. I checked with 25, 31, 40, 50, 63, and 80 Hz tones. No question, bass is twice as loud and tight.

I think the drivers must be wired out of phase.

Boy, I do like these subs though.....I even find myself listening to hip-hop all of the sudden.

Kcarlile,

I'm running the high-level (speaker-level) inputs from a tube integrated. There is enough current to wake up the subs (green light on), but it's as though it takes a minute or so to have the driver warm up. Its a faint "mechanical noise"....I assume to be voice coil hum.

Are you running a reciever with subouts? If so goose your output to the subs.

Ken, the sound sounds like R2D2 at a very low level and only last less than a second. It has been some time since I did any testing, but I was thinking I heard the noise the very first time I played anything, whether the Auto mode is on or off. Either way, I think the noise is normal and something internal waking up. I know Alan talked about a special/nifty little circuit built into these new 350's the gooses the performance and makes it Almost as good as a 500 in some respects.

OK, definitely different from what I'm hearing, then. Mine does come on instantly if the output volume is high enough... oh well, it's going back to its home for a little visit next week.

Mine just comes on. What am I doing wrong??

I have to disagree with you here, I have a similar setup and notice a significant improvement with inverted polarity on my subs. If you cant hear a difference then you should probably leave the phase the same but theres certainly no reason to if you can hear a difference.

Agreed. The reason for the phase switch is so you can "sync up" the phase (peaks and troughs) of the sound in the overlapping range covered by both the sub and the mains near the crossover point. Put it where it sounds best if your sub isn't in the same general area as the mains.

Ya know, I've never messed with that on my sub. Perhaps I should try it.

Some people like a variable phase dial. I find having a 0°/180° polarity switch covers enough ground. Having the drivers in sync is mandatory.

I agree with SirQuack...In most situations drivers facing the same direction and on the same plane, 9 times out of 10 you'll find 0° phase your best option (all drivers in the system are pushing and pulling in unison). However, there are situations (I believe my drivers are wired backwards or the amplifier in the sub inverts polarity) where even room acoustics can create problems. Trust your ears. If your ears do not hear any difference leave it at 0° and don't sweat it.

Another way to micro-adjust the phase of your sub is to play with the "subwoofer distance" in your receiver. Phase issues is the reason why often tools like Audissey does strange thing with subwoofer distance.

My statement comes from what Ian, Alan, and Chris (Audyssey), and I believe Dr Toole, say you should do in most situations. I've played around with phase until I'm blue in the face, graphs up the ying yang, etc. Phase, is only one component of how a speakers works within a room. Placement, room size/dimensions, etc. also affect FR. In all the testing I've done with 3 subs and many many placements, I always get better results using 0 phase.

I agree, as long as you actually HAVE room to move the sub. Not everyone has multiple positions available. When you don't it is nice to have subwoofer distance as fallback (no need for fancy dial on the sub itself where 0/180 is quite enough).

The problem with variable phase dials is that AFAIK nobody has ever made a "variable phase" circuit, it's a "variable delay" labelled as variable phase.

Ideally I guess you would have both; a switch to invert and introduce a 180 degree phase shift in all signals no matter the frequency, and a variable delay for fine tuning. Then again, since AV receivers frequently have the variable delay covered...

... (light slowly flickers on) I guess that's why the switch is standard these days

Woulda never gone off if you had a UPS.