Honey, my Volume Control Shrunk my Home Theater!
Pretend for a moment youâ€™re a customer. You just laid down your whole tax return on a new receiver or processor armed with the latest in THX post processing, Surround decoding and room correction. You operate with the idea that you will have limitless power and ungodly good audio. You take the system home, set it all up. It sounds greatâ€¦. until you attempt to turn the volume up and the pre/pro wont allow it due to a limitation in the volume control.
This is becoming a common issue with the latest crop of receivers and pre/pros today using a specific Volume Control IC. The list of processes that require headroom is quite long. It includes: THX, Subwoofer gain compensation (up to +8 dB), channel trims (up to +12 dB), downmixing (up to +11 dB of headroom in the worst case), Tone control, AutoEQ (up to 9 dB depending on the system), and others. So, in a worst case scenario (e.g. if you are in downmixing mode and the trim on your sub is near the max, or perhaps tone control is on) you will not be able to reach a master volume indication above 0 dB.
Allegedly there will be new Volume IC chips with higher headroom that will start to become available next year, but this is not something that can be adjusted in current models by firmware changes.
This issue has come full circle for me while conducting a review of a new high end Separates package costing in excess of $10k. so far I only see a few viable options:
3 options for the customer:
1. Turn off the room EQ if its boosting and keep all the trim controls below 0dB
2. Buy more efficient speakers
3. Send the receiver / prepro back and wait a year until manufacturers implement the newer ICâ€™s.
I will continue to report on this as I collect all of the facts and get the whole story. But right now, I sit with a monster amplifier that can pump the entire power supply into any speaker in my system if only I could get enough gain out of my preamp.