Temple gongs!

As a child I was so fascinated of the Bell that sounds so majestic when gonged. Even today I get the same feel of astonishment when I hear it go "Gong". It would rather not surprise many, if I say I have been having various bell sounding tones for the message and call alerts on my mobile. The intention of visiting a temple besides the fact of offering my prayers , is accompanied by the joy of hearing the uninterrupted, reverberating, deep and sonorous sound from the bell(Ghanta). I recollect to have read this piece somewhere - "A well-designed bell produce long strains of the sound ‘OM.’" Surely it does sound like that if you could closely observe.
I had a question on mind from a very long time, ever since I realised that I was attracted to this sound emanated by the bell - Why do one ring the bell when he/she enters a temple?
Do we need to do this just to obey the rules bestowed by our elders? Definitely there should be a purpose.
Do we ring the bell to wake up the Sleeping God before we offer our prayers so that he accepts it without fail? Ain't this sounding funny?
Do we ring the bell to let him know, we are entering the temple as a pretext of seeking his permission. Shouldn't he be knowing that we are coming in? Isn't he called the "Antaryaami" and "Trikaala gyaani" (the one who knows everything).
Poured in a bit of time into this little research and what I have found so far have some explanations that satisfy my inner soul to accept the facts told, but rest are taken as a part of conceptual understanding.
As stated in the Agama shaastra, ringing of Bells in temples is to ward off the evil spirits and to attract the benefecial devataas. The most widespread belief is that the Bell is sounded to invite the deity to accept the worship and prayers offered.
Esoterically, sound of bell, cleanses our aura (energy body), and help mind to become receptive. On entering a temple , its a wake-up call for the person who rings the bell. The moment he/she takes off the pair of shoes - one shoe of ego and other of arguments, he/she stands beneath a Big Bell in the temple. He/She raise hands to ring the Bell harder so that all senses within gets awakened. Vibrations enter mind and heart. Entire emotions are concentrated within eyes, hands are folded with all selflessness as his/her personality.
Those who are not able feel the vibrations of ringing bell, keep banging it. :-)
Ringing the bell helps to create a positive, congenial atmosphere that is free from negative vibrations(which distracts both the mind and the body).
Bells had other reasons also -> as most of the old temples never had doors and were located near hills and forest there would have been distinct possibilities for animals, insects, birds to take shelter. But bell sound doesn’t allow any of the living creatures to sustain inside for a long time. This seems more logical while other explanations cannot ruled out either.
As long as I enjoy the bliss of the emanating sound of the bell ringing, I dont have to worry about why it needs to be gonged on entering a temple.
- Ashwini