Axiom Home Page Forums General Discussion Home Theater EP500 Settings

I've put my Axiom system together (M80s, EP500, VP150, QS8) a couple of weeks ago (they should be broken in by now, it's been around 100hours of movie/music listening). I'm very happy with the way my system sounds both for music and for movies. I was also quite amazed at how tight the bass is with the EP500. My previous sub was incredibly boomy and caused my walls to give off unpleasant vibrations that ruined the sound of the music. With the EP500 much more precise bass without the annoying vibrations, which I'm very happy about.

I have a couple questions though, first of all there is no Trim knob on the back of my Sub, but instead there is a Subsonic Filter switch (current set to off). Can someone explain why and what that means? Second is from most posts I've read when I was doing research before I bought my system, people with the EP500 had their volume knob set to 1/4 or so, and that's what it recommends in the manual. Most comments mentioned that any higher than that was overkill, and my room is fairly small, probably around 1000-1500 cubic feet, if that. However, when I let my 3808 do the auto calibration I have to set the volume on my sub to about 3/4 or even slightly more (the knob doesn't do a full circle so it's hard to tell exactly where it is set, but I would guess roughly 80%) for it to give me adequate bass. Basically if I leave the volume at about half, the receiver gain for the subwoofer would get set at +6db (I'm not sure if that's right or not because I read somewhere that you should try not to boost signals leaving your receiver by more than 6db). All my other speakers get set to anywhere between -1db and +2db which seems more reasonable. When I turned the knob to 3/4 it set my sub to -1db which I thought was more appropriate so I just left it at that. The other problem was that it still set the sub as being nearly 20ft away (maybe the signal was too quiet) when it was only 7ft or so from the mic, but that's sort of understandable because most auto systems are bad with sub distance.

Can someone explain to me why I'm having to set the sub volume knob so much higher than others? Is it because my receiver is sending a -1db signal, is it that my sub is not broken in yet or is the sub amp not working properly? Would it be better to set my receiver back to sending a +6db signal and lower the volume on the sub itself or does it make no difference. Is there any way I can check if my sub is working as it should. My previous sub was a 200W Soundstage sub and even with it I basically had the volume at 1/4 and the sub gain probably around 2 or 3db ( hard to tell on my old receiver) and it gave me the same loudness.

For the record, I feel the bass is absolutely adequate in both movies and music and I've double checked the settings with an RS SPL meter from the sitting position for each of the speakers at 80db using the test signal from the 3808 and the sub seemed to hit the 80db marks spot on as far as I could tell. The only reason I ask is because most people rave about how crazy this sub is at producing low bass and although I'm perfectly happy with the way it plays now I've never had moments where I really went like "Wow, that was insane" or had my walls shake or had to turn my sub down because it was too loud (which it seems like I aught to given my tiny room). I should also say that I'm by no means a bass nut, and I don't listen to nearly the levels that these speakers could be pushed to. If I had to guess I would say I might have hit 90db on a few occasions watching movies (my receiver was set to -16db) but I've never sat and watched a movie with an SPL meter out. It just seems that if the knob is already at 3/4 then how much more can I really push the sub. The highest I've ever gone on my receiver was -6db on a concert recording for maybe a couple minutes and although I could still feel the bass (coming from drums and cello) it seemed like the sound got lost in the loudness of the other instruments (could have also been a poor recording - it was David Gilmour In Concert on DVD).

I suppose the main reason I've decided to bring up these questions is that I've demoed my system for two people now and both have said that they feel it's excellent except for the fact that my sub is lacking bass. One mentioned that it wasn't loud enough and another said that it didn't have enough low end. This got me wondering if maybe there's something wrong with my EP500 or of course it could be that that's simply the way the source was mastered to sound. Obviously I wouldn't say either of these people were experts but it's still interesting that they would both say that.

Apologies for the long post and hopefully someone could put my worries at ease, I just want the best sound I can get out of my system.

As I commented recently in Guy's thread involving his EP500, the reason for deleting the Trim control(but still showing it on the site)is unclear, since in my own use(older EP500)I've found it to be quite useful in balancing the mid-bass with the amount of room gain which varies with room size(smaller rooms have more gain at very low bass frequencies).

The subsonic filter which is now switchable in or out(previously I understand that it was fixed at about 18Hz)has no apparent connection with the disappearance of the Trim control. They affect different frequencies. The subsonic filter sharply cuts response below about 18Hz to protect against very low frequency rumble causing a problem. Except in the rare case that it does cause a problem the filter should be left off. The Trim control boosted response in the mid-bass above about 35Hz by variable amounts to balance variable amounts of room gain at lower bass frequencies.

As to the increased volume control setting on the EP500 which is now apparently required as compared with the previous version, this can result from two possible changes: 1. the gain of the sub amplifier has been reduced; 2. more likely the volume control has been modified so that it lets less of the incoming voltage in at its lower rotation, and so a higher setting is necessary to let the same amount of voltage into the amplifier to be subjected to its gain. Whatever the reason might be, if adequate volume can be achieved with less than the max setting it shouldn't be a cause for concern.

Well Escaron I've said it before and I'll say it again, I don't feel Axiom subs are 'rap artist' subs. They are instead 'audiophile' subs. And because of that I think they come off sounding a little 'weak' to those who have grown accustomed to the many subwoofer manufacturers that substantially 'fatten' the response of their subs in the 30 - 100 hz range. You absolutely can buy subs that slam harder and pound louder than Axiom subs if that's what you like. And I have also made it clear that I don't fault anyone for their own preferences. If you or your friends like 'in your face' bass, then hey... go for it!

With the Axiom line of subs I think you find more accurate bass response. As I mentioned, it may seem like a step backwards when you've been listening to a 350 watt JBL downfiring 15 inch subs belting out bass tunes for the last few years. But once you grow accustomed to the way your EP500 accurately follows the bass line in such songs as 'I Believe I Can Fly' by R. Kelly, or 'Its Not Easy To Be Me' by Five For Fighting, you'll appreciate the finesse this subwoofer displays.

But in keeping with my own 'to each his own' belief, if you are underwhelmed by the audiophile approach to designing a subwoofer, send it back and get something that does shake the plaster off your walls and impresses the socks off of your friends!

Escaron, I have both the older version EP500 as well as the newer version and learned through posts here and through Axiom that they simply adjusted the volume control to produce less low end loading (e.g., at the 1/4 turn). Nothing to be worried about.

The receiver's declaration that the sub is 20 feet away is because the sub has digital sound processing thus causing the sound to take a little more time to leave the speaker - which in turn makes the receiver think it is further away than it actually is. The receiver consequently retards the other channels' timing so that the sound reaches your ears at the appropriate time. So, IMHO, you should not change the receiver setting to the physical distance (although others will likely argue with me on this point).

Break-in has nothing to do with the lack of bass, speaker nor subwoofers "break-in". This is due to improper calibration or in rare cases there is something wrong with the sub amp. Don't be worried about where the position of the subs volume knob is where you start getting good output (unless you absolutely run out) 3/4 turn and -1 on the receiver is fine as long a you are getting a proper reading from the SPL meter. If you want a little more output increase the -1 setting on the receiver to +2 or +3 and little adjustments on the 500 volume knob and see if that makes any difference.

It seems with the new amps need a little kickstart from the receiver to get going.

Do you know if there are any more threads on these forums that talk about the digital processing and how it effects distance settings for the sub? I didn't realize this phenomenon existed so I just set the distance manually to the actual physical distance of the sub. Should I be letting the receiver keep it's own settings then? As far as I've been able to tell with movies the bass is pretty well integrated with the effects and other speakers and it doesn't feel like it's arriving too late or anything with my current physical settings. Mind extrapolating on what you said?

If you search with key words sub distance and delay on this forum or better yet AVS' Audyssey thread you will find information (with some references to Axiom subs for the latter forum). I let my receiver keep its own settings which report at least double the subs actual distance). But it's what sounds right that counts so let your ears be the guide.

With a difference of only a few feet, you're not going to notice synchronization problems with onscreen action. What does happen in the cross-over range where there is some overlap there will be a difference in phase of the sound pressure wave as it arrives at the listening position. This can cause some muddiness in that range.

I emailed JC at axiom about this (I have a new EP500 also) and he did infact say they lowered the gain control making 12 0 clock possible. And he said to turn that filter on only when listening to music not for movies. But I have mine past 12 0 clock ALL THE TIME for everything. I can even put it at full volume and it isnt really all that loud. I was thinking it was my sherwood R772 but now it just the way the sub is. The thing is when I try to increase my bass with the channel level it doesnt get louder it gets kind of distorted which I didnt think was possible. Do you have the Denon 3808 that is the amp I am thinking of getting but if it isnt going to make a differance than I wont. Still it sounds good I have the Epic grandmaster 500 just not a ton of bass.

Is your Sherwood under warranty?