An amplifier and speaker at full volume can be extremely loud, posing a risk to hearing and an annoyance to neighbors, and will often drown out other instruments in a mix in live shows.
To control the resulting response, a dedicated equalizer can be used to enhance or reduce specific frequency ranges.
The small volume of an isolation cabinet does not produce audible room reverberation, so the sound generally has to be enhanced with an electronic reverb.
A double-layer box with dead space between the layers still leaks audible bass, if typical plywood thickness is used.
A miked guitar speaker in an isolation cabinet is run into another channel of the mixing console.
Blowing a speaker is a possibility when using an isolation cabinet due to reduced audio perception levels.