have a question on the NES length counters.

A particular sound channel is silenced upon the Length counter reaching 0. This logically means that if a game wrote to $4015 and enabled Square 1 channel, unless they had previously entered a value into Square1's Length counter, the sound channel would still be silenced, and I'm guessing that the Square Wave 1 bit in the
$4015 register would also be set to 0. Is this correct?


Is there another sound doc besides NESSOUND written by Brad Taylor? His doc is good, but it leaves some questions unanswered.