Axiom Home Page Forums General Discussion Technical Questions EP350v2 versus EP350v3 specs

So I just spent three minutes measuring. I threw on a 50Hz tone, cranked my Denon's s LFE output to max (+12) and cranked the Denon's main gain.

With the 600 disconnected, I was measuring 5V rms on the cable. With the 600 connected, I measured 1.5V rms (not good). Doing the math, the 600's input impedance is about 43% of the Denon's output impedance. Again, not good. To prevent significant loading, the 600's impedance should be at least 10 times larger than the Denon's.

So, the 600 is loading the Denon's output too much. I suppose one solution to daisy-chaining is to crank the sub gain on the receiver and turn down the gain on the back of the 600. Give that a try.

mojo, what is causing this?

is the denon at fault (not supplying enough output voltage) or si the ep 600 at fault here?

I would say it is the Axiom as Mojo and I have daisy chained other subs together OK as long as we left the 600 out of the loop.

Jason's right. But I blame myself. I should have known better and asked the question on input impedance before I bought it. I can't beat myself up too hard though because I could have never imagined that the 600's input impedance would have been this low. It's rather unusual.

I suppose this is one way of ensuring that the receiver output can never saturate the sub .

Does the 500 have this same problem?

It will be interesting if someone from Axiom will shed some light on this issue.

I've placed my 600 back up front below my center channel because it looks cool. I place one 350 to the right side shorter wall below the acoustic panel. The other 350 is on the left full wall about 1/2 back and next to my back row of seating.

I have the gold plated adapter at the receiver splitting the 600 on on cable and the twin 350's are daisy chained currently. With the receiver on 0dB level, the 600 is at about 6 o'clock on the gain to achieve 73dB, the 350's are about 2-3 o'clock which is very high to achieve the same dB's, but with the 600 hooked to the Denon I don't have much options.

What is interesting is that Jakeman originally told me to set each sub individually 5 dB (70 versus 75) below the other speakers, when all combined they will be slightly above the others, about 78. I remember Ian stating in his video to set the first sub the same SPL as the speakers, then introduce the other subs. He went on to say most would expect a 12dB gain I think, because of the 2 additional subs, but because the RS meter is not showing you what is going on below 50hz, it is misleading, an your gain is in the higher frequencies.

I noticed when listening to music today the subs were not impressing me. So this time I calibrated the subs individually, but at the same SPL as the speakers, about 73dB. What is interesting is that I didn't get the same 8-10dB increase as before when they were all running. This time I ended up with about a 3dB gain combined or about 76dB's. For whatever reason things sound better overall now.

Not sure if it is different placement, with the 350's on the side walls and the 600 up on front stage, no sure.

Anyway, I took some pictures of graphs from each seat to show you the changes, will start a different thread for that.

Interesting results, Randy. With the two 350s daisy-chained, no problem, as was expected. However, with the 600 added to the daisy-chain, the issue previously described appears, for reasons difficult to fathom. Adding the 600 would of course further lower the overall impedance of the setup because of the parallel nature of the connection, but this wouldn't seem to be so critical. Possibly Ian can shed some light on the 600's operation, as was mentioned in a previous post.

Yes John, I put togethor an email to Brent and JC, who are going to forward it on to the two Chief Engineers, Ian and Tom.

The results were also the same if I split the signal at the receiver.

Yes, that's as would be expected, since splitting at the receiver sub output with Y connections is electrically the same as the split done internally in the subs when daisy-chaining.

Incidentally, on another point, it would still seem to me that with the 600 front and center that the 350s would be best placed in the left and right rear corners.

The problem is that the back wall is a walkout to our back yard. I could get one to the rear let corner, but not sure how I would route the cable over/under the door and trim to the other corner. I was not thinking when I wired the basement to run extra coax runs to the rear wall locations.