In response to 1) Yes it does play Loudly with few watts. But it does not play at low to normal volume very well. So to me perhaps JA did not speak to quality of the low volume sound: see #3 I may just not understand all he did say.
He is a very knowledgeable person for sure, so he must know full well that power not used has no effect. If the speaker plays very loud with a few watts, the untapped power reserve will just be there on reserve, and will have no effects whatsoever until it gets tapped, i.e. used. Let's say you only need 10 W to get you 105 dB (ref level) peak at you mlp, 105 dB peak is so loud that you will not likely tolerate when listening to orchestral classical or jazz music. Then a 125 W amp will be operating well below its limit most class AB amps tend to have low distortions from about 2 to 5 W and up, and started to increase gradually from about 50 to 70% of its rated output.
Your Sony's measurements are not available online but take a look of the 5400ES's:
Sony STR-DA5400ES A/V Receiver HT Labs Measures | Sound & Vision (soundandvision.com)
You can see that this Sony actually has a very flat curve, THD increased very gently, to about 0.007% when it started to "clip", at about 125 W.
It is very possible that in terms of accuracy/transparency, the internal amps of the higher end Sony ES amp would perform better than you Anthem entry level power amp. That does not mean it would sound audibly different in a blind tests. THD+N is just one criteria albeit an important one, and low THD typically is a good indicator that IMD would be low too. Also, the distortions at low output level seems excellent, so I doubt you have to worry about the highly audible crossover distortions either.
2) Settings and configuration I believe are correct.
I did use a Y connector from Sony Front speaker Pre-outs in order to utilize the 4 channels of the Anthem.
Since you have to turn the volume up when not bi-amping, I would suggest perhaps one set of the connections and/or cables may be bad in some way. If you are using RCA connectors, you really should inspect each and everyone carefully. There is good reason to have to turn volume up simply going from single amp to biamp, unless you forget to put the jumper back but that would be so obvious, that you would have notice right away.
3) I reviewed the link with JA's measurements and respectfully cannot really understand it well enough to determine it that measurements change from low to high volume. Also with all do respect having been in an orchestra a jazz band and rock band, I have faith in listening with my ears regardless of what a measurement may tell me to hear. I won't doubt the measurement but I know when something is missing or amiss.
Which part of his measurements are you referring to?
Regardless, as I mentioned before, you probably, say even likely heard what you heard, but I highly doubt the difference was from passive bi-amping. So to me, this not about debating whether biamp vs not is worth it, but more about troubleshooting, there is something not right, I am 100% sure of that, but obviously I can't prove it, just wish I was there to find the real issue/culprit.
SACD of Rush Counterparts 1st song Animate. Low level drums were almost hidden, Geddy's voice a bit muffled not clear or bright. Once volume was increased to minimum of 52, drums did begin sound clear and normal and so did Geddy but tweeters did seem to have some distortion and were not perfectly clear as when bi-amped. So, Could it be a bad speaker wire? Why would it be corrected and back to normal.
I will try it again and make sure the wires and jumpers are on there correctly.
It was rather late last night. Fresh ears would also help. I will also switch to DB volume instead of 0-99.
Yes it could be bad wires, and/or bad connections, it might have been partially "corrected" at higher volume if the "bad" isn't really very "bad", but bad enough to increase the overall resistance between the power amp binding post to the speaker terminals to the point damping factor becomes so low that you are able to hear the results. That's just one scenario and there are likely other unknowns. At higher volume, whatever the issues are, would still be there but the adverse effects might have become less obvious with the higher output voltage.
I mention damping factor as an example of what could have been affected, the real cause(s) could be more complicated.
Damping Factor: Effects On System Response | Audioholics
I had believed that a Powerful amp at low volume could easily drive speakers clearer at a low volume than a lower powered amp and I had thought this experiment meant that this was likely what was happening.
That is absolutely one of those many forum myths. Such claims are just claims, that cannot be back up with scientific facts. Ask
@VMPS-TIII about his 60 W Hegel amp lol!1 And I am talking about SS amps, let alone many nice sounding tube amps rated <100 WPC. Yes a 300 W amp vs a 150 W amp will make a difference of 3 dB, but if the need is only 50 W under worst case condition, then either amp can drive the load easily and effectively. If your need is 150 W, then okay the 300 W would likely be able to do a better job, all else being equal, because its output would remain "cleaner" during the peak demand moments.
I did buy an SPL meter but haven't used it or learned enough as to what it meant yet.
I saved the link to the calculator and will get those when I get a chance. I may have to work this weekend so it will take a little while. Will work on that and let you know Thanks again Peng.
Your questions and suggestions are greatly appreciated.
Of course, take your time, its just a hobby, work has to take priority for sure. As I said, this, to me is more about troubleshooting. If you do happen to have some bad connections and/or cables then once that's fixed, you may be in for another treat of improved sound quality whether you bi-amp or not.
