audience in the suspense, as a knocking is heard...and more knocking. At this point, they must quickly retire to their bedchambers to appear as if they have been asleep. The immediacy of the situation is created withMacduff knocking at the castle and entering in the ensuing scene.

Early in the scene, suspense is built with confusion of off-stage voices and what  Macbeth hears or thinks he hears.  First, from off stage, Macbeth asks, "Who's there?" indicating that he thinks someone is about when there shouldn't be anyone except his wife.  Then he comes on-stage and asks Lady Macbeth if she heard the sounds. She is perplexed and doesn't understand because she only heard Macbeth.  Macbeth goes on to tell her he heard voices praying and one called out "Murder". Then, he says he heard a voice call out, "Sleep no more! Macbeth does murder sleep."  The voice goes on in this same vein according to Macbeth and he doesn't know who it was or where the voice came from.  In this high anxiety scene where Macbeth has just murdered Duncan, the confusion of voices and sounds creates a great deal of tension.

Macbeth opens with the witches and the audience knows that what will follow will be dramatic and unexpected, in keeping with the witches mantra that "fair is foul and foul is fair." (I.i.10) Even Macbeth's first appearance is on the battlefield and his connection to the witches is established as "so foul and fair a day I have not seen."(I.iii.38)  

Macbeth is set in Scotland and much of the drama takes place in the dark, whether it is under threat of a thunderstorm or in a castle. The darkness establishes Macbeth's own mood and creates a sense of foreboding. The scene is then set for chaos and evil. Macbeth, the audience knows, is very affected by circumstance and opportunity and his "vaulting ambition" will ultimately be satisfied as his belief in the witches prophesies and his own invincibility combine to cause Macbeth's final ruin.

The initial setting which reinforces the mystery surrounding the witches and the possible consequences if Macbeth "shalt be King hereafter"(I.iii.50) encourages Macbeth's delusions of grandeur. His confusion, but at the same time excitement at his improved prospects , enhances the tension created by this setting and, although he knows it "cannot be ill; cannot be good,"(131) it gives him "earnest of success."(132)  

Later, when his castle is the setting, Macbeth, with Lady Macbeth's constant aggression - masquerading as encouragement - succumbs to evil forces as "the bell invites me."(II.i.62) After he has killed Duncan, he is so affected by his surroundings that he can barely stop himself and continues his murderous activities, killing Duncan's servants and, even outside Lady Macbeth's knowledge, Banquo.

In order to continue, Macbeth needs some confirmation and again seeks out the witches in (a dark cave, a cauldron boiling) which sets the scene at the beginning of Act four, revealing that Macbeth is far from finished establishing his future. Macbeth becomes more tense the more he hears and demands to "be satisfied" (IV.i.103) failing which he promises "an eternal curse fall upon you." (105) He is even challenging the witches now, so overwhelmed by his surroundings.

Macbeth is already a confident soldier but knowing that he cannot be defeated "until Great Birnam Wood....shall come against him" (93) and no man "of woman born"(80) can harm him, Macbeth fails to recognize that these forces are conspiring  to create a tension that he is barely able to restrain. The environment is one he is so comfortable in, a battlefield and he will realise too late that the witches are nothing more than "juggling fiends."(V.viii.19)  

MacDuff is first introduced, although his presence is previously noted, when he comes to wake Duncan at Macbeth's castle. He jokes with the porter and seems relaxed until he discovers Duncan's body, revealing that "murder hath...stole...the life o' th' building."(II.iii.65-6) The audience sees how affected he is as he reminds the men, as they discuss the "gore," to "look to the lady."(118)He is immediately suspicious of "treasonous malice"(131). The setting then creates a tension of its own for MacDuff because he is noble and forthright and, in seeking to do the right thing is mindful of his surroundings.

It is also notable that the setting is what alerts MacDuff and makes him suspicious "lest our old robes sit easier than our new."(38) He is fully aware of his position and responsibilities and wastes no time in trying to settle the matter. He intends to return to Fife.

MacDuff's family are in Fife but his allegiance to the throne causes him to leave them and go after Malcolm in search of the truth, never expecting that he is exposing his family to danger. The setting in Fife makes him feel that his family is safe. He does enquire after them, aware of danger, especially after sharp criticism by his wife and when he hears of their deaths in "one fell swoop"(IV.iii.218), he is overcome with grief. He vows to avenge their death against "this fiend of Scotland."(232) 

Ultimately, MacDuff is also confident on the battlefield and he feels confident that he can overcome Macbeth in this setting - the battlefield. Tension is enhanced for MacDuff as Macbeth reveals his increasing madness. MacDuff, noble to the end, gives Macbeth an opportunity to "yield" and kills him when Macbeth refuses. 

MacDuff is once more in a setting that lends itself to his demeanour, where he can honor his King and fulfil his obligations, releasing him from all the tension.  

Lady Macbeth, Macbeth's "dearest partner of greatness" (I.v.12) has a drive and determination which would threaten most people and, indeed her husband. She is less affected by the setting at the beginning and it is more opportunity that creates tension for her. However, as soon as she hears of Duncan's imminent arrival, she is plotting and scheming "the fatal entrance of Duncan." The setting then becomes very relevant and does increase her confidence and so create some tension as Duncan will arrive "upon my battlements,"(36)-  her home. 

The audience sees Lady Macbeth's self-assurance when she takes control after Duncan's death and returns the daggers. Similarly,after Banquo's death, Macbeth is haunted by his ghost and, even though they are now in the palace at Forres, it is her domain as his Queen. She is able to allay the fears of guests when Macbeth is delusional, confirming that "the fit is momentary."(III.iv.55) Lady Macbeth takes in in her stride.  

As Lady Macbeth loses hold over Macbeth, she becomes increasingly affected. Although, she is still in her home, she is affected by her diminishing control over the situation. She cannot even "wash away" the imaginary "spot." A strong-willed, self-possessed person like Lady Macbeth can no longer cope in a setting where she is not controlling everything and the tension is enhanced, ultimately signalling her demise as she descends into madness.