In most cases there is a connection between tinnitus and a damaged
inner-ear. This damage is due to noise, which has damaged the outer hair
cells. Then the auditory system and mainly the brain reacts by sending
"signals", which we are heard as tinnitus. In most cases it is the high
frequency area in the inner-ear, which is damaged and therefore are
connected to hearing loss. This hearing loss can be measured by a
audiogram, but in many cases it the hearing loss not possible to measure
in usual ways. Then you must be measured regarding OAEs (otoacoustic
emissions), which are those "sounds" that the inner-ear sends. If no such
sounds are not registered within a frequency area, then you have a hearing
loss.

Wearing ear plugs protect you from having more hearing loss - at least for
some years. Ear plugs do not in any way lessen you tinnitus sound. Hearing
aids can compensate the hearing loss and in some cases lessen the tinnitus
sound. But you take off the hearing aids, the tinnitus sound is there like
before.

There are no quick fix for tinnitus. Personally I believe that a sound
therapy is to prefer compared to all other treatments, like drugs,
acupuncture etc.