Axiom Home Page Forums General Discussion Technical Questions Subwoofer rattle normal?

Hi...

I recently bought an EP400 subwoofer. It works great at low volumes. However, I'm experiencing a phenomenon that I don't quite like when listening at medium to higher volumes, and I'm not sure if this is standard/normal for this subwoofer.

When listening at medium to higher volumes of bass heavy tracks, I can hear the aluminum woofer rattle at a much higher pitch than the sub-frequencies that I expect a subwoofer to make. It's a rattling that is layered on top of the bass - when I hear that, it makes me kind of cringe, like trying to walk on a sprained ankle (the 1st metaphor that came to mind). I don't know if the subwoofer is damaged, or if i'm further damaging it by playing it at this level, or if this is part and parcel with subwoofer performance. I honestly don't feel like i'm 'cranking' the volume with it! And this is a subwoofer - not exactly a light parcel... I'd hate to think of the postage cost to send it back. (sigh)

Any words of wisdom out there?

have you calibrated it with the other speakers, normally 75dB's using the receiver test tones or auto setup. You may be running the sub to hot, meaning you have the gain to high on the sub and/or receiver.

GC, as Randy indicated, if you have the sub calibrated correctly, i.e., you don't have it adjusted much louder than the speakers at a given volume, there should be no such rattling even at fairly high overall volume levels.

What's the cubic size of your room? I hope you are not trying to fill a large space with that sub. That would contribute to over driving it.

Rattling or even "fluttering" sounds during heavy bass passages can be contributed to many things including the driver bottoming out, port noise (is this sub ported?), poor assembly like loose screws securing the driver and or amplifier (air escaping) or even user setup like having the receiver subwoofer pre-out set too high which in turn clips the signal.

The sub is sealed.

I'd give Axiom a call.

I might have misread your initial post. If the EP400 uses some sort high pass brickwall filter, its possible what you are hearing is the sub ringing during those demanding bass tracks that dig low and loud.

It sounds like the same kind of noise I was hearing with the EP175 that I bought. Upgrading to an EP350 fixed the problem for me (or in your case downgrading to an EP350). It just wasn't enough subwoofer for the space so it kept bottoming out.

As BlueJays1 said... how big is your room? The EP400 is specifically designed to give you low bass in a small room only. If you're in a larger room, you might be pushing it too hard.

I would think the DSP would prevent damage from over-driving, but that doesn't change the fact that you might be misusing it if your room is larger than a bedroom.

There may be something wrong with your sub, but as others have said you may be over driving it. Depending on the size of your room, you may need to consider an ep500 or ep800. As Ken suggested I would contact axiom. If you decide to upgrade to a larger axiom sub you might ask if axiom can help with the return shipping on the 400 (it never hurts to ask!)

I'm using the EP400 in my bedroom, which, if memory serves me right, is 14'x11'... the height, I'm not sure, but it's pretty average for an apartment.

So did you calibrate it correctly as we asked above. Where do you have the gain setting on the sub and receiver? It should be matched to the other speakers using the built in mic, if you have one, or an SPL meter.

Please give me a call on our toll free number at 1.866.244.8796 and I can assist in troubleshooting the issue.

FYI, the iphone app store has an SPL meter that is fairly accurate. It is the ultimate ears app.

I doubt i'm over-driving it, though I'm no expert. I'm using it with M3 bookshelves and a vintage Marantz 2235b (35watt RMS).

I'll turn the receiver volume up less than 1/2 way (usually about 1/3), turn up the EP400 volume less than 1/2 way (usually about 2/5), and then play a bass heavy song (like dub music or hip hop) and when the subwoofer is really going in and out strongly, the rattling sound will start.

I've tried using both RCA and speaker-line to the subwoofer, and experience the same rattle at these volumes.

I've spoken to Brent and will give the EP400 a bit of an inspection. We'll see how that goes...

Are you sure its the sub?

I have an Outlaw sub and only have the volume on its amp turned to 1.75, yet when I turn up the volume with Bass heavy tracks I also get an annoying rattling noise...

I found taking the metal framed pictures off the wall resolved the Subwoofers issue

snazzed

For clarity: The picture frames were vibrating against the wall.

Sounds like something isn't right. Definitely contact axiom. For the $$$ you spent on an ep400 you should be more than satisfied with it's performance in a bedroom.

Edit: feel free to follow with comments about bedroom performance

I'm betting you are over driving the sub, it isn't meant to pound with heavy bass just fill in the lower end, not that there still couldn't be something loose but I would guess what ever is rattling was brought about by being over driven inspite of the DSP. Perhaps the DSP program is a little too lenient allowing too much movement.

Just thought I should let Brent know - I wasn't able to do the suggested inspection of the EP400 last night. Instead, took the gf out to see The Tea Party immediately after work, and then crashed at her place. Aw well...

Priorities, Dude.

Oooohhh, Charles gives a tongue lashing.




Likely with a mechanical cow tongue.

I don't have an actual beef with him?

I'm sure some of you might be interested to know the problem resolution, no?

Well... Brent had me poking around the subwoofer a bit to make sure no internal wires were rubbing/hitting against the aluminum woofer. None were. But during my checking, I noticed that when I pushed down on a certain area of the bulbous rubber ring that runs around the aluminum cone, that a 2 or 3 inch stretch of the outer lip of the rubber rim would push up a little bit. Upon closer inspection, I saw that that section of the rubber had become entirely unglued from the subwoofer chassis.

When I played some heavy bass tracks afterwards, I heard the same rattling as before. Then I continued playing the track while using my fingers to press down along the unglued rubber edge and... PRESTO, perfect bass!

Well, the following day I talked to JC (Brent was away) and was blown away by what a quick and trouble-free solution he offered... he'd just send me an entirely new woofer to install into the box. I thought I would've had to refurbish the thing myself with some super-glue, but no! Very, VERY impressive customer service!!!

So, in a few days, I should be up and running smooth, rattle-free bass. Yay!

Thanks Axiom!

this means no head rattling for you!

glad for you and enjoy!

:-)

Very good. An air leak around the driver could definitely cause rattling. Hopefully it fixes the problem. Nice work.

An air leak, yes; but more specifically, the flapping of unsecured rubber.

awesome, good to hear you got it resolved..

Rubber cement dude, not superglue.... But its a non issue now.. but next time if you ever have a subwoofer that the surround needs repair.

if it is not under warranty, that would be an option.

yup, that is how may manufactures attach the cone to the rubber/foam shroud... back in the day anyhow... there are probably stronger more specific types of rubber cement compound out now.

Excellent Axiom customer service, GC. From some places you might have got "Well then, as long as you hold your fingers there it sounds good, right?"