Axiom Home Page Forums General Discussion Advice from Axiom Owners EP350 or EP400?

Yea, it was funny when I figured it all out. I was standing there with a big smile on my face listening to my EP350 blasting me with bass. Then I thought...D*mn! I have to call JC @axiom right away...then I thought...Holy ****! I have to go on the forums and tell everyone I'm an idiot!

LOL...oh well...it's all good now * I'm lovin the 350.

Dana

Well, I don't know about any of you but I am certainly confused!

I have only 1 place to place my M80's. It sounds like to me that the bass you are now hearing is from the ports out of the back of the M80's now that they are closer to the walls. I understand sub placement having an effect because it picks up the walls and floor differently in different places. Seems to me a 300 watt ported sub should be heard WELL even if the mains are placed on your head.

I'm NOT convinced!

Bob, I thought the same as you. But since I have Google'd subwoofer placement and watched axiom video on subwoofer placement, seems to me (although, I'm proof I don't know alot) that speaker placement is absolutely critical.

Also Bob, since you're a PA guy, I did find this article by Peavey,

http://www.peavey.com/support/technotes/soundsystems/boundarycancellation.cfm

Dana:
While 'm glad that everything is working right, I'm surprised that the m80s would have enough output to cancel out your sub. In fact, moving the M80s closer to the wall would reinforce their bass, and theoretically cancel out more from the sub.

Did you ever play with the phase control on the 350 (because this is the type of situation that warrants that control)? It changes the "phase" of the sub output so it matches the other speakers. You don't, in effect, want one woofer "pushing out" while one next to it is "pulling in" because the sound wave created by either is inverse to the other and will cause cancellation. This is also why you want to make sure your speakers are wired correctly in terms of your "pluses and minuses".

Since I had so much fun creating the wiring diagram last week, this week I've made a "Phase Diagram":



(This may have been more than you needed to know, or too basic for you, but now I can copy and paste the text and graphic the next time someone has a question on the topic!

That's a great article and confirms what I stated. Placement of the "Sub" can be critical. Not the mains. Being involved with PA (somewhat) I have been in discussions of low frequency cancellation. That can happen with 2 subs and is a good reason NOT to have a system set to "large" where the mains are carrying the same frequencies as the sub. It is the very reason why you should be setting your system to "small" when using a sub.

A question that constantly comes up on the PA form I visit is when using a double 15" with a horn cab. The bottom 15" is considered a "quasi sub" that extends lower than the upper woofer yet no where what a real sub will produce. Now these folks want to place a sub underneath this speaker to get real bottom. There is way too much overlapping frequencies with this arrangement and usually gives a muddy low end rather than the big bottom that they are expecting using "extra bottom". This also goes along with the "small" settings in HT. There is also complaints of phase cancelling where ther is loss of bottom. But this cancelling happens more with 2 subs than with anything else.

If you had your system properly set-up with the small setting than you should have heard your sub no matter where it was placed and it should have been loud. My understanding of sub plcement in HT is more for smoothness and level frequency throughout the room (boominess). I still can't see the mains placement having anything to do with the loudness of the sub.

But I really am not that knowledgeable in any of this.

Nice diagram, Mark. Sometimes it's easier for us noobs to understand with straightforward drawings without so much of the technical "jargon".

Mark,

I did change the phase on the 350 several times and checked my wiring as well. I don't know for sure, but when I was having these issues, and I look back on it now, I see that the M80's are closer to the back wall and kinda more "in line" with the 350. Where as before, the M80's were either way in front of the 350, and due to the forward location of the M80's the sub was in line with the 350, but all away from the back wall. If that makes sense. It's hard to describe without posting a layout of my room with the before and after speaker locations.

Dana

If you're talking about co locating (stacking) two subs they will not cancel each other out. They will in fact have more output in this configuration.

If you have a SPL meter you can run some test tones through the EP350 and take readings on your SPL meter and see if there is any measurable difference between each phase setting. If there is leave the phase set to the one that produces the higher reading.

Bob, remember that he was running his M80s on large, which means they were producing frequencies down to about 30Hz--well into sub territory. I'm not sure why moving the sub didn't fix this either, but I don't know the particulars of his room, and I'm not an audio engineer.