Alan Lee was superb for Ipswich, scoring twice and making two more goals, days after signing a new contract, while Franny Jeffers, who Town wanted to sign but joined the Owls instead, didn't get a look-in against the side he was on loan to last season.
Town were in front after 80 seconds through a Lee penalty and they dominated throughout, only taking their foot off the gas in the last few minutes to allow Wednesday a barely-deserved consolation.
Ipswich were awarded a penalty just 35 seconds into the campaign when Wednesday skipper Lee Bullen pulled down Pablo Counago and Lee confidently sent Lee Grant the wrong way from the spot.
It was 2-0 on 11 minutes when an offside-looking Lee escaped down the right flank and whipped over a perfect far-post cross for Gary Roberts to volley beyond the helpless Grant.
Incredibly Town's third meaningful attack produced another goal on 25 minutes when Counago won the ball off Frankie Simek on the halfway line and fired an angled ball into the path of Lee, whose angled volley bounced over the arms of the diving Grant.
Wednesday finally threatened when Steve Watson almost got on the end of a Marcus Tudgay pass, before Tudgay was given a sight of goal when Jeffers had a shot blocked, but he dragged his angle shot well wide.
Jon Walters had an effort deflected over after more good Counago play and he then came close with a close-range header which a grateful Grant dropped on close to the line.
Simek was booked for diving after falling to the ground following a burst into the box and he then crossed for Tudgay to head firmly but straight at Neil Alexander.
The second half was understandably quieter, although Ipswich continued to hold sway with Lee twice going close to a hat-trick, steering an Owen Garvan cross just wide and almost capitalising when Grant spilled a low cross.
Lee was involved again when Town scored their fourth on the hour, playing in Walters down the line and he crossed for an unmarked Counago to coolly beat Grant.
Tommy Miller almost steered home a Counago lay-off after a neat 1-2 between the returning pair before a stream of substitutions disrupted the flow of the game.