Boltgunlover,
I think you are mis-informed. The quality electronic hearing protection such as the Etymotic GSP-15 do not have a response time problem, They control sound by two methods; 1. the compressor amplifier responds instantly to sound and reduces the gain by up to 20 dB. This is for medium background noise. 2. for your or your neighbors gun which creates an impulse noise of 160 to 170 dB SPL but for a limited duration, the quality hearing protection limit the level of sound they can produce to about 117 dB SPL due to circuit design, choice of speaker and battery voltage. So, when your gun goes off, the amplifier tries to run the speaker up to 160 dB SPL but the designed in limitation limits the output to 117 dB SPL.. Simple, no time delay, just a limiter! This sound level is actually below what is transmitted through your Mastoid bone.
On the other hand, the quality hearing protection like the GSP-15 uses an analog amplifier which offers two important qualities; 1. the fidelity of an analog amplifier is essentially un-matched by digital amplifiers and, 2. the digital amplifiers have a minimum time it takes for the signal to propagate through the digital amplifier. This time is in the milli-second area and may not be matched in both ears. The end result is that the poor fidelity and time delay of the digital device does not allow proper "situational awareness" that an analog amplifier does. That means that if you are in law enforcement or the military, even using hearing protection (Analog!) you can still tell where "that noise" is coming from. Not so good with digital.
Check out how many digital hearing protectors have been tested and approved for a tactical environment! The GSP-15 has.