Originally Posted by N8DOGG
Geez man. 85 dB's is dolby reference right? yes.
No, 85 dB is the THX reference level used by theaters. That's why it's used by home theater owners, to try to match the theater experience, as I pointed out in my first post here.
Do all receivers have the ability to play at reference? no why? because different speakers and different rooms with determine if your system can play at reference. Why would you calibrate your system for reference if you system cannot hit reference? You wouldn't.
That's true. But just because a particular system can't be calibrated to the standard reference level doesn't mean it doesn't exist. You can calibrate to any particular level you want, and it would be a benefit over not calibrating, but that wasn't the point I was originally trying to make. Re-read my first post and you'll see that I said exactly the same thing (that 85 dB is specifically used because it's the THX reference level). I got derailed because it sounded like in your other posts you were talking only about level matching the speakers. I guess I shouldn't have been as specific about THX reference level for calibration, but as I pointed out first thing in my first post that's the level most people use for a specific reason.
With audyssey and audyssey pro, you set a mic up, run it and the software on the pro will allow you to do set the system curve. It's all done by computer and your avr. The user does pretty much nothing but move the mic around and hit start and stop. The user can change things like distance, speaker size, crossover point if they want but it's generally better if left alone. The pro software will then set the reference point of the system. It's always 0 but it's changed to be 0 by the calculations it's made. Could be 10 dB's more than factory. So like I said, I and audyssey changes the reference point for each system. Some units, you can't change the 0 and the new reference may be -12 from 0. It's noted and the user will have thier own dolby reference point of 85dB's.
I understand how Audyssey works, I have just never used it. I have used Pioneer's MCACC which is similar. I'm not sure I understand your discussion on changing 0. They way I understand these systems to work is that they set the overall AVR output to -0 dB, and use the individual speaker cuts & gains to get the desired SPL at the listening position (along with delay correction and EQ for room correction).
Are you saying you would have -12 dB be the reference point because the amp is too powerful for the speakers and -0 dB would cause damage to them, or at least cause distortion? That makes sense. I'm not sure just how much individual levels can be cut, and it probably varies by processor, so if you can't cut the individual level enough I guess you do what you have to.
85dB's is the average volume, not the max.
Reference is freaking loud, although some peoples systems can handle it fine, other cannot handle the peaks and distort or clip.
All your doing is picking link off the net. How bout you actually go do it, then you will have some more insight.
The link I chose is Audyssey's site where their engineers answer questions from users. They specifically state that their system calibrates -0 dB to 75 dB SPL. Maybe it fails gracefully if it can't, I don't know. The similar Pioneer calibration routine I have used steps the left front channel up in volume until it distorts. If it hits 75 dB SPL first, it uses that. If it doesn't, it uses the max to set the other speakers. It sounds like from your description Audyssey may do the same.
85 dB is the average SPL, you're right. I forgot about that. 105 dB is the max, and 115 dB for Dolby Digital for the LFE because it's mixed at +10 dB to the other channels. I agree that it is insanely loud for home use. Most people listen at best at half that volume or a bit less. That's why systems like Audyssey & Pioneer MCACC use 75 dB SPL as the reference level (because -10 dB is half the perceived volume, in case anyone is curious).
Also, it's kind of asinine and unhelpful to the conversation to suggest I'm just grabbing links off the internet. I have calibrated speaker systems. I haven't used Audyssey, which is why I've said as much and went to the company itself for the information I posted. The other link was simply to provide more information about THX reference levels and calibration, as, again, it seemed like you were discussing level matching earlier in the thread and calling that calibration.
Anyway, I think the conversation has run it course. It's a wild tangnt for the OP, who is probably best served by your original advice to just do it at a comfortable max volume.