This is a byproduct of digital inputs and multiple formats - any receiver has to know what format an input is in so it can properly decode it, and it must be allowed at least a moment after the signal starts to identify that signal. In some cases, you can have an input that just assumes it will always get the same signal (such as PCM for a CD input) and avoid any signal acquisition delay, although that can still backfire (such as DTS CD's). In other cases, the receiver must have a chance to analyze the incoming signal and tell if it is PCM stereo, Dolby 2.0, Dolby 5.1, Dolby EX, DTS 5.1, DTS ES, or something else. It can be very quick, but if it will allow any of those inputs to exist then there must be at least a very short signal acquisition delay. It can be short (the 990's is easily under half a second), mild (the 970 and 1070 reportedly land at under a second), a bit on the long side (the 950 clocks in at a second or more as I recall), or even longer (Emotiva's LMC-1 reportedly can experience a 2 to 3 second delay).