Boss Paul Jewell was frustrated by the manner of the goals Ipswich conceded in the defeat at Luton.
Defender Janos Kovacs headed both goals as the Hatters won 2-0 win at Kenilworth Road on Saturday.
It was Town's first defeat of the pre-season campaign and Jewell told the club's official website: "They were two bad goals, two free headers from set-pieces. That's certainly not the first time I've said that and it's something we are trying to put right."
He added: "We were much better in the second half than in the first and their keeper made three or four outstanding saves. If we had scored one then we would have gone on to win the game.
"There were some positives to take. Massimo (Luongo) did well again and we passed the ball well. It's always disappointing to lose but it's about working towards the first game of the season."