I have an EP500. I bought it about 5 months ago. I use it exclusively for home theater. My receiver is a Denon 4311. The sub is great however I have a recurring issue that really annoys me.

On occasion, something will happen to the sub and it will play at a much reduced volume. This usually happens when I power up the equipment although it may have occurred while watching a movie once. The fix is a sub power cycle.

I only run the home theater a couple of hours during weekdays and longer on weekends.

You see I never know when I turn on the equipment if the sub is OK or not so for the last couple of months I have taken to playing back a 35 Hz tone at my normal listening levels to ensure the sub is ok. The fact that I have to do this just bugs the hell out of me.

Has anyone ever had this problem? I am not sure what the cause can be but one thought is that maybe a protection circuit kicks in to reduce volume and somehow gets stuck.

To make matters worse, the sub makes a buzzing/vibrating sound at about 40Hz which is also very annoying. I did open tickets for both issues and I have removed the amp looked around for anything obvious.

Anyway the sub is awesome but I am really quite disappointed to the point that I am considering getting rid of it and getting another non-axiom. I also have QS4s which are very nice and was planning to get fronts and a center to replace my Polks but that won't happen now I think.

Any advice would be most welcome.

what is the level of "a 35 Hz tone at my normal listening levels" ?
what is your "normal" level in dB SPL ?

are you running Audyssey in "evening" or "night" mode, this is called Dynamic Volume. Have you calibrated all your speakers using an SPL meter or using Audyssey?

What did Axiom have to say? They're usually quite good with problems like this.

On the buzzing sound, I'd just double check that it's the sub doing it and not something in the room.

If it IS the sub, take the driver out and make sure one of the wires isn't touching the cone or something like that.

Hello - please call us via the toll free number 1.866.244.8796 so we can resolve your issue.

It may not be the sub at fault, and actually a Denon setup issue. I would still make sure you have Dynamic Volume turned off.

I would turn off audyssey all together of it is on

no way not all togethor, mine sounds actually a lot better with Audyssey and Dynamic EQ on, Transformers never sounded so good, bass in all seats awesome.

Thanks for all the replies. Sorry for not responding sooner, I just got back home from Europe.

I do use Audyssey and I think it is great. I leave Dynamic EQ always ON and Dynamic Volume I keep on Day and at times may turn OFF. I have of course calibrated with Audyssey. I also have a meter that I have used in the past but I have come to trust and rely on Audyssey.

I leave the EP500 volume at mid level. My normal listening level on the Denon is 55% (absolute). After Audyssey does it's calibration, I bump up the sub level about 3db.

Also, I use a RCA cable to the sub. The RCA to 1/4 Phone adapter that plugs into the XLR combo socket which was shipped with the sub really didn't in my opinion provide a good connection so I bought a proper RCA to XLR adapter which fits nice and tight. I really hoped this would cure the drop out but it didn't.

When I say I play a 35 Hz tone at normal levels I mean, I want to feel the sound. I am not over driving the speaker. I check the cone throw and it looks quite OK. With an EP500 I expect to feel the sound and when it works properly, it sounds very nice (when not buzzing/vibrating).

I am pretty sure the buzzing/vibrating originates from the sub because if I press on the back amplifier panel near the high level in (top right), the buzzing almost completely stops. It must be something loose but I did remove the amplifier and everything looked tight. It will almost always vibrate when I play a low frequency tone which you know I don't really mind as long as I don't hear it when watching a movie but I have heard it watching movies.

A few mentioned to turn off Audyssey but I completely disagree, I have had it with two Denons over the last couple of years and it works real well especially with the 4311. Dynamic EQ ON with Dynamic Volume on Day works awesome at low and high listening levels.

I never use Dynamic Volume unless it is late at night, not to wake the kids upstairs, but like you I enjoy Audyssey.

it sounds like you have a problem with your sub...

You know I really had to force myself to use Dynamic Volume, it just seemed so wrong to do so... But you know, I find it just sounds better with it on. I find that bass comes across better with it on. I use it most of the time.

"I am pretty sure the buzzing/vibrating originates from the sub because if I press on the back amplifier panel near the high level in (top right), the buzzing almost completely stops."

you put the finger very near the source of the problem, now you need to put it at the exact spot, figuratively.

I had a 500 once with the same problem, at certain frequencies I heard a buzzing type nose. It took me forever to figure out that when I applied pressure to the amp, near the top as well, it would stop. I believe axiom said air must be escaping around the seal. You could try tightening up the bolts around the perimeter.

Have u called axiom yet?

Yes I have. They are sending me a new amp. I am very anxious to receive it and test it out.

Update: Axiom decided to send me a whole new unit You really can't ask for much more than that.

Nice!!

Good deal!