Sorry, I did not write it clearly.
1. Without additional added amplifier, just use marantz, after A/B tests with and without the bi-amp connection. It seems that marantz sr8012 do makes better sound with Bi-Amp connection to the B&W 702s2. It seems that this way more "current/signal/power" are delivered into the speakers. Sounds very beautifully !
However, I have to turn up volume up to about, at least, 60% to really get that sound quality that I was expecting.
In a demo room of bestbuy, they are using two Mcintosh monoblocks driving the B&W speakers, the volume
only turned up to 30%, but the sound quality is wonderfully clear and fully. May be I missed many other factors :-(
So my way of catch up with this and trying to understand this, is to use two, cheaper but powerful and efficient, Bel Cato REF1000m monoblock, it can deliver about 500 ~ 600 W to the 8 ohms of the 702s2.
2. With added amplifiers: the pair of Bel Canto REF1000m, use the marantz as an amplifier. I used the jumpers linked the speaker connectors ends. So only one pair of cable connecting from one speaker to the one monoblock, Positive to Positive, Neg to Neg, No more Bi-Amp connection! All in stereo mode to compare.
There is no obvious improvement on the sound quality at same level of 60% volume as before. Not to mention at lower level of 30% volume.
3. Is the dB part of the volume control? Is the another part of volume control is to increase/decrease the current/signal/power into the speaker connection?
So 30% of the volume is: 30% = 30% dB of Max + 30% current/signal/power of Max?
4. I am not sure what is the way to describe the, added, amplifier effects. One way of my understanding is to use Pre-Amp volume to judge the, added, amplifier effects. Please help me to understand this better.
May be the whole addition is useless to achieve what I had hopeful. Then what is way achieve lower volume better sound quality for the whole system?