Axiom Home Page Forums General Discussion Technical Questions SPL Meter

Yep know all about that did it with my old sub although it ended up back in the same place.

This EP500 is a big bugger and I will be struggling just to get it to my seating position.

My main concern will be fine tuning it once it's in it's new home.

I've been wondering; if trying a sub crawl, does it matter which direction the sub is pointing?

The direction the sub points can affect in room response. I get a better overall response with my sub firing forward in its current position compared to firing into the center of the room.

What is it's current position?

For the most part the subs frequencies waves come out omnidirectional below 80hz or so, so in my opinion it does not matter much which way the driver is facing. Think of it this way, if you throw a pebble into a pond, watch the ripples expand out in all directions.

I could be wrong, but...

My understanding of sound is that all sound waves follow the "pebble in the pond" model, not just low frequencies. That is to say, they all emanate from a point, and travel spherically outward.

The difference is human ears. Human ears have trouble pinpointing sound generation points in the low frequency bands.

Graeme, you say you are not blown away and have set the sub up acorrding to the manual. Is the sub level matched to the speakers with pink noise playing? if so try adding a couple more db to the level for the sub, but the idea for the sub is to not be 'blown away' but it should just be filling in the lower end the speakers are not good at reproducing. You really shouldn't notice a sub is even on during music only during movies.

Currently it is on the right side of the room on the wall facing towards the front of the room. By turning it 90 degrees (shoulda paid attention to that thread) I significantly reduced the 70Hz null and somewhat reduced my ginormous 50somethingHz peak. I can't say it was a night and day audible difference, but it was definately measurable.

Fred - agreed, the direction makes a difference due to the way the sound reflects when facing different directions in your room (think of a rock in the pond that the ripples bounce off -> move the rock, the reflections come back from a different direction). [Can everyone keep up with my ueber-scientific explantions?)

With that said, I've never heard anything close to a night & day difference from changing the direction of the sub either, but when graphing the response of the sub facing forward versus sideways, there are differences.

It's worth trying a different direction if you're trying to find the most linear response in a given position, but it is unlikely to cause a huge difference.

Jason

Keep in mind that any difference may not be due to the direction that the driver is pointing, as such, but that the distance of the cone from room boundaries will vary because of this and may be the variable that's significant.