The Absolute Sound disects SAM

[ogs]

It's a lot more noticeable on stand mounts David. The bass goes deeper(Lower in frequency) but not louder.

I used it with a stand mount, the Dynaudio Contour 1.3 SEs I was using before I swapped to Focal Sopra 2s, and I've used it with the Sopras. I actually find the change that concerns me, the hardening of tonal character I mentioned above, is more noticeable with the Sopras, I can't recall noticing it with the Contours. I also think it became more noticeable after the CI board upgrade to my then 130 so I wonder if there was something in the change in the OS when we got the CI board which had an effect on SAM in some way, did they change something which interacts with SAM in some way?

I think there is an increase in loudness as the % setting increases but I also think that there may well be a reinforcement of our perception of lower frequencies when their phase angle is more closely matched to the phase angle of their overtones and it's possible that what I'm hearing is partly a result of low fundamentals being more in phase with their higher frequency overtones.

I have not thought very deep about this, but I believe SAM is a "closed system" in the sense that the DSP gets detailed info on voltage, current and frequency going to the speaker continuously. This is compared to the SAM profile for the speaker and the DSP makes adjustments accordingly. So SAM depends on a lot of information from the amp stages it is part of - and would not work standalone on an 'unknown' amplifier. ADH does something similar. In the drawing below the CTRL signal is embedded in the feed from the Class-A stage to 'cancel out' unwanted things in the Class-D stage. The CTRL signal is changing with level. Same with DPM. Power demand is calculated continuously based on the music signal and volume level and the power supply delivers based on this.