Axiom Home Page Forums General Discussion Technical Questions Understanding the EP600

Well, I finally got the sub set up, with the new amp. that Axiom shipped, since the first one was faulty (volume control not working).

Now that I have it set up, I would like to understand it a little more. There are a few things that are new to me, so maybe some of you could make it easier to understand what the 'features' are for, on the sub.

The 'Trim' and 'Phase' settings...what do they mean? What should they be set at (as a general default)?

What is the difference between phase of 0 deg. vs. 180 deg.?

What is the difference between 'Flat,' 'Load,' 'Full,' etc. on the trim settings?

Any advice/guidance would be great. And TIA for your help, suggestions.

i.

There should have been a pamphlet that was shipped with the sub that explains most of what your asking.

Here is a link to the HTML version of the manual.

http://www.axiomaudio.com/manual_ep500600.html

Thanks SQ...guess I must have missed the manual...while moving/packing/unpacking, etc. I will check the box, and meanwhile, thanks for the link to the document. Nice reading material for lunchtime.

See ya.

The EP600 is one of the finest sounding ported subs around. Those are all good questions which though well covered in the manual are not easy concepts to grasp at first.

Firstly Phase. Aside from the technical explanations, I like to think of it as a switch that synchronizes the in-and-out movement of your sub's woofer with the woofers in the main speakers or with the drivers in another sub. Depending on distance and time the in and out movements will be "in" phase or "out" of phase. Ideally they will all be moving together at the same time, though this is easier said than done particualrly if the sub and mains are positioned in different parts of the room. If the drivers are "out" of phase the resulting waves can cancel each other so pay particular attention to getting the woofers in phase even if that means moving the sub to a less preferable location. When subs are out of phase people often complain of weak bass. Try the phase switch in both 0 and 180 positions to see which position gives you the loudest bass at the prime listening spot. Invariably that is the best position for the switch.

Next Trim. The trim settings are a great feature which all subs should have but few do and is one of the great attributes of the Axiom subs. All rooms have room gain at lower frequencies which can result in a bloated response down low. The EP subs boost response above 33hz to compensate for the effects of room gain and flatten the response to compensate for the natural room gain. This feature is particularly useful to users who don't own an equalizer. I believe we will see more and more manufacturers incorporate trim settings into their designs and it is one of the many features which set the Axiom EP line apart.

The EP600 is a fabulously articulate sub and a tribute to Ian and Tom's ingenuity though it must be setup properly. If you don't have some diagnostic tools like an SMS equalizer, start with setting the trim flat and laying it in your prime listening position. ( I know its heavy but it will save you a trip to the weightlifting gym. )

Next crawl or walk around the room while playing a bass track you are familiar with the mains off until you find a place along the side or front wall where it sounds best. Place the sub there. Turn on the mains and flip the phase switch to where the bass sounds loudest. Next turn the mains off and measure the loudness with a radio shack metre.(You have to buy one, it is an essential item). Turn the trim switch up until there is less volatility in the metre. Adjust the crossover frequency at the receiver/processor to 1.5X the lowest +/-response of the mains. Measure and adjust the mains and subs volume to the same DB and enjoy.

^^ Thanks JM...I have been playing around with the settings, on the sub, and believe that I have found a happy medium where everything seems to be working in harmony.

I did buy an SPL meter, and have basically configured all of the HK's surround modes (took me a little while). I moved the sub to the left wall, and the mains closer together (I posted a pic of this in a thread a few days ago). So far, the bass has improved, and hits pretty hard. I have to keep it turned down some...since I might wake the neighbors (I am a late night type).

Other than that, I will take the advice above, and play around some more. At least I know the settings that I like, so far, so I can always revert back, if need be. Thanks again.

i.

Still waiting for the espresso to kick in so maybe I'm not hitting all cylinders yet.....but how would one "turn the mains off"? I have the HK7300 and am drawing a blank.

Also, what happens when you're stuck placing the sub in only one or two locations due to room configuration? Any tricks worth sharing in that regard Jake?

Not sure about the HK, but what I did is on my Denon Remote there is a "Front" button that cycles the use of A or B for the main channel. If you select B, and have nothing hooked to the B speaker terminals, you will get no sound out of the A speakers.

If you can't do it at the receiver, the universal solution is to pull a wire at the speaker connection.

Another technique which I use when dealing with these time domain issues is to tweak the sub delay at the receiver. While not a phase setting in the strict sense delaying the sub much more than measured distance will tighten the sound and also help get the woofers moving together. At a minimum add at least 3 ft or a metre to measured distance delay to account for the DSP in the EP600. Assuming the sub is in front of you, add still more delay regardless of distance if bass notes sound less distinct when the mains are on.

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Adjust the crossover frequency at the receiver/processor to 1.5X the lowest +/-response of the mains

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Or set it a couple of Hertz above the 3dB response point, depends on the speaker response and just how fast that dropoff is to a particular brand/model.

Alternatively you can have another individual turn up and turn down the sub crossover while you listen to material and decide where the bass gets too 'muddy' or overbearing (too much bass overlap with the main speakers) or when it gets too thin or lacking (an obvious bass hole).
Surprisingly the results should come pretty close to the 3dB response point. I have my EP350 set at the 55Hz mark with the M60s based on this adjustment and the bass is nice and smooth. Note the the 55Hz mark also conforms to the 1.5x concept.
No noticeable audible drop outs when testing with a bass frequency sweep so i continue to run my M60s as large, full range.

So Jakeman, your saying if the Denon has my EP500 at 27ft, when actually it is more like 13ft, I should add another 3 ft to the delay and make it 30ft?

I'm intersred in the reply to this also, since I also have my 500's delay set by Denons auto setup.

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Still waiting for the espresso to kick in so maybe I'm not hitting all cylinders yet.....but how would one "turn the mains off"?

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Unplug them.

Randy, my interpretation of John's suggestion is the same as Dave's. Since your Denon has already measured and compensated for time delays in the sub amp(leading some to complain that the longer measurement was "wrong"), no further manual correction is necessary.

I was trying to diagnose the odd surround effect i was receiving with DPL II and i needed to turn off my main speakers. Just by unplugging them you can get a real idea of the sounds that are sent to the surround speakers and really understand how 'supplementary' they are.
It was a neat effect to hear only the surround output.
We did the same for the subwoofers during the SVS and Axiom comparison. Again very interesting to hear only the bass notes during one's favorite song.

Right you are, chess. It's also interesting to do the reverse, i.e. use DPLII but disconnect all speakers but the mains to hear the effect of extracting varying amounts of the ambience and/or center material from them.

Just checking back into this thread but I see Dave and John already answered. Randy's Denon has already done the delay measurement so no need to add the 3 ft for the DSP. In my setup I add yet another 3 ft account for the processing of an SMS equalizer. My EP600s are 3,9metres from the main seat but I have them set at 6.0metres in the delay. It seems tighter to my ear there. Notwithstanding the Denon's room correction setting, I would suggest adjusting the delay manually up or down and listen if it tightens the bass further because it may help the overall phase with the mains.

John, if I'm not mistaking aren't you running a couple of EP600s placed mid-sidewall of your room?

I was home for the most of today and a played around with my single 600 quite a lot and I must say that the just aft of mid-sidewall placement in our 25'x14' room sounded extremely good ... I used the Rives test tone CD prior to moving the 600 but didn't manually graph or use the CD after moving it to the sidewall location. Prior to movement I did place the heavy beast in the listening position and walked/crawled around the room with the mains turned off, man I moved that 600 around so much today I thought I'd have a hernia but probably nothing more than due to time it ended up back in the right front corner. After a couple of more tries and tweaking I do believe the sub *may* end up mid-sidewall even though that isn't the ideal location for aesthetics ... but I have been informed that this is *my* room.

Rick. Sounds like you had a good workout moving that 100 LB behemoth around the room. Midwall placement is often a great sweet spot for flatter FR especially for single sub placements. A second sub across from that one on the far wall would really flatten it further as well as provide benefits with lower compression and distortion. Its why I always suggest people by subs in pairs. There was a technical paper by Harman that proved that dual subs in midwall placement was an excellent configuration, almost as good as quad subs. http://www.harman.com/wp/pdf/multsubs.pdf