Axiom Home Page Forums General Discussion Technical Questions trim settings on identical subs

Hi everyone,

One of my EP500s recently developed an intermittent popping sound and then became non-functional with the status light turning amber/yellow. Axiom sent me a replacement amplifier and I installed it last night. What I noticed was that I had to set the trim level to about 10 o'clock on the new amp in order to level-match it to the other EP500, which is set at 7 o'clock. Previously, both subs were level-matched at 7 o'clock on the trim. For those of you with two or more subs, I wanted to inquire about your thoughts and experience on the differences in trim settings. Thanks in advance and Happy Holidays !

P.S. I am in CT, where we are expecting 8-9 inches of snow today and another 3-4 inches tomorrow before a second storm comes on Sunday !

Did you notice if it was the same model amp before you installed it? I have noticed that on both of my EP500s, I have them at about 6:30 (which is very low). I would have liked a level adjustment with a little finer control (which it sounds like you may have now).

I assume the new amp is for an EP500 as they have "500" written with a white marker on the plastic cover in the back.

I would have thought that the same trim settings would give the same SPL level since the amps are presumably bench-tested for a particular level with regard to trim before being shipped out.

Hey John:
Yeah, I'm guessing that Axiom changed the knob setting / gain to give people a little more flexibility. I don't own one of their newer subs (so this is not a "knock" on Axiom), but I've always gotten a kick out of the marketing behind volume controls.

You want to offer, say, a range from -80dB up to +15dB for example. Why do most high-end manufacturers give you this total range with maybe a 70° turn of the knob? And cheaper units go from "mute" to clipping with a 30° turn of the knob. As a matter of fact, the cheaper the unit, the less "knob-turn" it takes to achieve full output.

I guess the marketing department has determined that people will feel an amp is not powerful if you have to turn the volume 3/4 of a revolution to achieve a "normal" volume.... and the cheapo manufacturers want to give a feeling of power by letting their inadequate amps crank really loud with just a little turn....

Of course, SOME flexibility has to be allowed for different (lower) input levels. If engineers were in charge instead of marketing people, we would probably see volume knobs with more "travel"...

Off the soapbox now.....

Anyway, I'm guessing that's what Axiom has done with newer sub amps....

I've owned a 500 and 600 (not at the same time) but the trim levels for the most part have been the same. Now, when I move the sub to say the back corner compared to the front wall, the trim will be a little different, my room is 31 x 30 x 9. I did have a replacement amp sent to me once for the 500, but it was the same in regards to the trim level. Maybe Axiom has recently changed something, not sure.

My 350 twins are at about 1 o'clock (different scale than the EP's)

Actually we'd probably find the knobs on the inside of the chassis, sealed away behind a set of plates with no other purpose, and which would only turn if the planets were aligned...


Off my soapbox now...

Update:
I am sorry to say that there is something wrong with the replacement amplifier. It simply does not have the same power as the other two amps; not even 50%. In “Full” setting with trim set all the way to maximum, the amp measures only about 78 dB on the SPL at best. My other EP500 would produce the same SPL at only 7 o’clock position and at 9 o’clock position, the SPL exceeds 90 dB and the house begins to shake. The original amp on the malfunctioning sub had the identical powerful performance as my other sub, and the SPL produced at each trim setting was identical between my two subs. This new replacement sub seems so significantly lacking in power that one can hear the obvious difference without even using an SPL meter. I just emailed Brent at Axiom. Will see if he replies over the weekend again; he replied on a Sunday before !

John - try unplugging your original ep500... and run just the new one without having the first one daisy-chained at the same time. I'm curious if output increases in that scenario. (I've seen that behavior with 600s)

Jason

Hi Jason,

Yep. I did that as well by connecting the LFE directly to sub-2 (with the replacement amp) rather than daisy-chaining the LFE from sub-1. Same low output.

well bugger... other than the obvious, which I'm sure you've done (changing cables, outlets, etc.), I'm out of creative ideas.

The other thing some people recommend is connecting an MP3 player directly to the sub with an RCA cord from the headphone jack just to confirm it's nothing weird your receiver is doing. (unlikely in your situation, but it's another quick test to rule out the receiver in any of the behavior if you get the same difference when using another source)

Jason

Dang, that does suck, you must have got the amp I sent back months ago. Just kidding. Anyway, I'm sure Axiom will make it right, you could call them as well, they man the phones until 11pm eastern I believe...

Hey Randy,

I just checked. Amp is from Axiom, not Emotiva...

haha, yeah, but over the years I've sent back 2 amps, one for my 500, and one for my 600 that went bad...maybe you got a refurbished one.

You may be right; not enough power for Randy may be more than enough power for someone else. But, Axiom should have expected that the A1400-8 has spoiled me to a point where no amp could measure up.

I want a 1400 bad...just don't think I can talk the boss into that one.

While the 1400 is one impressive beast, I am sure your Odyssey Khartago/Stratos Special Edition monos (if I recall correctly) should be no slouch either.

Please drop by for a listen if you happen to wander into CT.

(Am I hijacking my own thread?)

I do enjoy the Odyssey's, they are one finely built piece of audio equipment. I will say that the newer Denon's with the latest Audyssey features, and the new Sherwood Newcastle receiver coming out with Trinnov has me curious. I've tossed around the idea of selling my Odyssey's to upgrade to a newer receiver...

John, I wonder if you somehow ended up with an amp for the 350. I know you said it had a written 500 on the back but it could still be wrong. The 350 has half the power of the 500, so it makes sense that your dials are not in the same place.

Jay, the pictures of the amp for the 350 V3 look black and squarish. The amp for the EP400 and 500 is larger, champagne in color, and have "10123" written near the bottom to the left. The differences in appearance are not subtle.

I was just thinking it was a possibilty as the subs use the same enclosure so the 2 different amps would fit, but never really thought about the differences, as I never looked at the pics, I should have thought of that.

An amp with lower wattage should only be a few dB less powerful in output... it sounds like we're talking a much bigger difference than that....

I think so too. The difference is night and day between the replacement amp and the other amp on sub-1 (as well as what the currently nonfunctional amp-on sub-2- was capable of).

Now that you have two subs and two amps, are you up to putting the new amp in the working sub to rule out that it's not something other than the amp that is to blame in the second box?

That would at least save you from getting a second replacement amp and having the same problem if the problem turns out to be inside the "quiet" EP500.

Jason

I doubt that the problem is with the enclosure and the driver, but I will put the replacement amp in the working sub and see if I can duplicate the same low power output. Thank you for the suggestion, Jason. I will report back later today

That was my thought as I read through the responses this morning.

John - I agree... a long shot to be sure, but so is getting a replacement amp that doesn't work correctly!

Either way, you're dealing with long shots at this point.

Jason