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Quote:Originally Posted by j0hnnyyyy
im guessing you want me to change the volume to db reading on receiver, the steps were labeled a little different then what you guided me on the receiver but on music ill listen about -27db and movies a little bit louder it sucks because i live in an apartment and i use to blast my music around -15db and crazy neighbor almost came down breaking my door yelling turn my subwoofer off. so now i have to listen at a moderate sound or turn subwoofer off.
Johnny, I reckon you don't need an amp. Here's why...
Let's say the loudest you generally listen to movies and music is at master volume -15dB, but let's adopt MV -10dB as the loudest you'll ever get.
Now, SMPTE/THX/Dolby cinema reference calibration (which Audyssey adopts) stipulates that a -20dBFS
input signal is to produce 85dBSPL at the listening position (LP) for each main channel. This 20dB of "digital headroom" means that a peak output level of 105dBSPL at the LP for each main channel is theoretically possible (ie. with a 0dBFS input signal).
A system properly calibrated by Audyssey (and other auto set-up routines) has a total electro-acoustic gain set up to play at this reference level (-20dBFS --> 85dBSPL) when the MV indicates 0dB. Are you with me so far? So, at our maximum of MV -10dB (10dB below reference), the theoretical peak SPL expected to be produced at your LP is 95dBSPL (105dBSPL - 10).
Now, in typical residential rooms, sound pressure drops off at around 3 to 4dB each time you double the distance from the source (speaker). If I assume a longish 4m distance from your speakers to your LP and an average of 3.5dBSPL drop off per doubling of distance, you get a total drop off of 7dBSPL. This means that your B&W's will need to play at 102dBSPL at 1m distance to produce those 95dBSPL peaks at your LP.
Your B&W mains have a sensitivity of 90dBSPL with 1 Watt at 1m. So they require 12dB of gain from the amp to play those 102dBSPL peaks. Now, a doubling of input power from the amp is required for each 3dB increase in SPL, so 12dB of gain on 1 watt requires 16 watts. That's right - the maximum amplifier power required to produce program peaks at MV -10dB at a 4m listening distance, with your speakers is 16 watts
. If you cranked it up to MV -5dB (perceived as twice as loud as MV -15dB), 50 watts
would be required to produce 107dBSPL program peaks. If you turn it down to your indicated maximum of MV -15dB, a mere 5 watts
is being called upon to produce 97dBSPL peaks. In addition, all power requirements will be marginally reduced if your listening distance is less than the assumed 4m.
These power figures are for program peaks
and are still well below the continuous
power rating of the Denon X4000. It means that in your current situation at your preferred maximum levels, a power amp will make zero discernible difference and is not needed.
If you've got cash burning a hole in your pocket, spend it where you can make real sonic improvements: speakers and subs.