Yesterday I had the pleasure of welcoming both Jay "jakewash" and Mark "doormat" to my home.
Jay stopped in to return my A1400 which he was demoing for the past month and Mark stopped by to check out the EP800's.
I will leave them to post any general comments / thoughts they may have. Jay did mention that he thought the Denon amp may be muffling the sound slightly on the highs compared to the Axiom amp. A short discussion resulted and it was decided a A / B comparison was warranted. Jay had to leave because of commitments and Mark and I decided to do the comparison.
We went to a 2 channel setup
We would listen to a number of tracks switching speaker connections during songs to try and hear any differences we could make out.
1) Sound levels dB's were different
Axiom was louder by about 2 dB
2) We could not really hear the muffling Jay was referring to
There may be a difference but the switching would need to be immediate to catch this difference if any

Conclusion
We decided a PROPER A / B would be needed since what we were doing wasn't accomplishing our intended goal. Flawed because of:
a) A proper switch is required to do the immediate amp switching. The switch would need to allow for level matching the 2 amps.
b) Same cabling connections. We were using XLR's off the Denon and RCA's off the Axiom
c) This is more of a question. How to properly detect any audible differences (REW ?)
If anyone has any guidelines for a proper A / B test let me know. I am going to find the switcher first.

That's it for now and the rambling
After the long weekend I hope Jay and Mark will give their impressions

Mel N.

I hope to hear from the sub demo king " Jay" on his impressions of the EP800

I would think only your ears are required to detect audible differences. Otherwise, I think you're referring to measurable differences. You may ask Alan for tips on material to use for comparison purposes.

I guess I didn't ask the question properly and will try again
If you are A/ B ing 2 amps and your ears are telling you that there is something that is different between the 2. How can a person measure that sound difference. I mentioned the REW because if you graphed both amp setups would the graphs give you any info in relation to the differences in sound your hearing.
This is all new to me because I would expect there would be no noticeable changes.
Still on a search for a switch which will allow for this test.

would this be of any help? there is a free version. Just plug a mic in a laptop and analyze what's coming out. You should be able to see what's coming out of both setups.

Thanks for the link I will check it out

First, I would think you need to know what it is that is affecting the sound. In amps they talk about clipping, distortion, slew rates and the like as affecting sound quality.

Now, you can measure the difference in distortion between two amps (if you have the right equipment), but how do you know that specifically is audibly affecting the sound the amp produces?

I seem to remember Tom Cumberland talking about slew rates and cliping when I asked him about the A1400 and sound quality. I keep hoping that Alan will jump in to one of these discussions as I think that he is probably the best one on the boards to address this topic.

First I have to say the pics of Mel's system do not do it justice, it is absolutely gorgeous.

I felt the highs were not as open sounding with the Denon amp as I had heard with the Axiom amp at my house, but I was pretty much only in 2 channel for my listening and we had multichannel for the 40 minutes I was listening at Mel's. My room being samller could be the biggest issue for the differences I could hear as well as my 3808 might just have had a problem which could be why it died.

I would have to say the EP800 IS the sub I had been looking for, too bad I didn't wait a year longer before I bought. It has all the low end vibes my PB13 does and that beautiful all encompassing, rich texture, yet smooth sounding, the rest of the EP series has as well. Well done Axiom.

Mel,

Here is the switch I am using for my A/B speaker test. It also has source A/B. You need to be sure to turn OFF the prev. amp (or speaker) BEFORE turning on the new amp (or speaker). I don't know if issues would arise, but after Jay's story, I wanted to be careful. It does have a protection circuit, but decreased SPL on speakers about 1.5-2 dB. No idea what else the prot. circuit might influence, so I left it off.



I don't recall what I paid for this 10+ years ago, but it must have been inexpensive for ME to buy it.

dude, you need to learn how to resize your pictures a little smaller..

Mel, just a brief comment on amplifier comparisons(which really should be double-blind to have validity). If as you say the Axiom amplifier was about 2dB louder(apparently because of higher gain with the same voltage input), this would easily be enough to explain a report(not that you made such)of "wider sound stage" (which amplification as such has no ability to accomplish), clearer highs, stronger bass(both highs and lows are more prominent at a higher listening level), and other differences which amplification doesn't affect. This is why one of the basic requirements in blind testing of amplifiers is that the levels be matched to within 0.1dB.

dude, how about asking nicely?

Its all good, Dave and I go wayyy back.

John, IMO, double blind listening only needs to happen to ascertain which one prefers; and as they, or myself were only interested in any auditory differences, a simple switching back and forth just to see if there is a difference was all that is needed and in my case, in my room, with my 3808 vs the Axiom amp the difference was noticeable even at the same SPL readings. I even went so far as to have the meter mounted on the tripod beside me and I would adjust the volume to match while playing through the songs, I still had deeper bass output and wider taller soundstage with the Axiom amp than my 3808 alone.

Mel is running the Denon seperates which are with out a doubt worth more then my 3808 and as they were unable to notice the difference I am willing to bet it has a similar output level/sound quality as the Axiom amp, unfortunately for me my 3808 does not.

Hello Onn,

Buddy, you have to be the luckiest son of a gun to be able to test too amps of that quality. Personally, who cares about the slight differances, no disrespect intended, i would put your 4 m80 fronts and sides on the Denon and the rest on your axiom and your in Audio Heaven.. you may need an addition 17,000 sq ft of land around your house not to scare the neighbors into thinking that their bleeding ears is an act of God. My God Man..2 ep800's...8.3 on the Richter scale...and all in that liquid wood finish...

Peter
I have given Randy so much well, poop in the past, I have it. IT coming!

But Randy, dude, that switcher is 1 1/2' wide !!!!

I do need to Learn that !

Back in car on iPhone. Not to worry, wife is driving.

First off, thanks for the demo, Mel!

Secondly, for the following three hrs I couldn't bring myself to listen to my car stereo.

Third, you were actually pretty close to convincing me to drop another 7500 on my system. Fortunately (unfortunately?), after spending all that time in my crappy, dying car, I'm thinking maybe I should put at least half of that into new transport (with a better sound system).







So maybe just the 800.

As far as the totally unscientific A/B went, even with the slightly higher dB on the Axiom (with neither system being in any way stretched, probably only pumping out 1 or 2 watts) I could not detect any difference in sound quality between the two. I could not hear anything lacking from either source, except, maybe, Jay's "sparkling highs".

I think A/B testing is only effective at differentiating between relatively gross differences.

IMHO, you have to live with a component for a while. If you sense the magic, you will listen to that system more than one which lacks it.

I think some, if not all the differences I could hear has more to do with my room and setup than anything else. I sit closer to the speakers, my M80s are much closer to reflective walls and are not nearly as wide set as Mel's.

I have been wondering how much different Mel's system would sound with the M80's sitting in the spot occupied by the EP800's and vice versa. I think having the M80s more in direct line with the listener (more like my set up) may present the more pronounced treble I was refering to, or just a bit more toe-in on the speakers in their present positions.