At that SPL are you sure the ''crack sound" wasn't from the room coming apart ! LOL
On my SPL meter (Rat Shack ) placed at 12ft from the speakers, all I could handle was a reading of 92 DB. Stuff in the room was vibrating
and I could not hear the sound that you guys heard.
The gear first test :
Oppo 203 CD player direct to Pioneer SF-850 Active Crossover.
Two Quicksilver 60wt ea. mono block tube amps to Altec Horns w/ compression drivers. (high level)
Phase Linear 700 ser.2 full comp to (mid/low ) Altec 416-8b 15'' woofers.
Phase Linear 700 ser. 2 quasi to two Sea's 13'' DQ1w subs.
The gear second test :
Same gear except switched out the tube amps to a McIntosh SS 2505 on the horns.
The 3rd test :
I set up a simple Near Field system with speakers 8ft apart, listening distance at 6ft , 88Db on the spl meter
Still could not hear the crack sound.
The gear :
Oppo 203 cd player
Nad 3020 (pre amp section only)
McIntosh 2505 Amp
Kef LS3-5A speakers
A Headphone test might be the best way to go ?
This Shpongle gives me flash backs man !