Originally Posted by audiovideoholic
Why is anything over 128db clipped in the digital domain? I run songs and demos all the time well into the 140s but have never noticed any distortion or other funky stuff. I set my signal chain up optimally and it still allows me to play that loud.
And why wouldn't the signal just go past the (theoretical) 0dbFS like normal with a WAV file since I have changed it in my optimization? I have just never heard clipping and I play at levels well above 128db just like many others here do. Heck most of us run a 20db house curve and still crank it well past MV reference (125db on subs). I just don't get it as long as the system's gain structure is setup to max out the amps? That is how I set it up and never an issue.
I just find that statement incorrect especially when mixing pro and home audio gear.
I'm not the best person to fully explain this but, I will give it a try. Our avr's will produce a maximum signal a 0 db. Any thing less for the digital signal is a -4 or -6 db for example. In other word the gain control is telling how close to reference we are producing the signal. In theory we can't exceed 0 db. unless something happen.
Boosting above reference the signal has to undergo alteration. In hard clipping the signal is squared of and any info that is not clipped is just lost. Soft clipping, re-quantization can occur to fill in the missing signal. This were avr's may differ in their processing ability This should sound OK. Beyond the soft clipping several things start to happen, the amp produces excessive current and power, VC damage, XO damage or amp damage can occur or, there will be an increase in harmonic distortion.
This is one of the reasons some of the guys have mega systems and so many subwoofer. In essence, they are compensating for each of the above problems to run their system safely. In short, you can't produce what is not there and movies are based off a reference standard digital signal. Quantiztion of the signal is different from reproducing the pure signal. A signal meant to produce 70 db at reference is clipped beyond 70 db but, it not as likely to cause problems.
Because the signal is digital, this can be thought of as an independent variable other than just the spl. This was the way I interpreted things from my readings. Maybe someone else will chime it with some more info on the topic.
All clipping is not bad and can allow us to push our systems beyond reference. This does not mean care should not be take and equipment damage is possible. WAV files that undergo quantization cab exceed 0 db and not be overtly distorted. This is not the same with movies and I don't know if there is a rock solid number to hang your hat on.