Smell-O-Vision did not work as intended. According to Variety, aromas were released with a distracting hissing noise and audience members in the balcony complained that the scents reached them several seconds after the action was shown on the screen. In other parts of the theater, the odors were too faint, causing audience members to sniff loudly in an attempt to catch the scent. These technical problems were mostly corrected after the first few showings, but the poor word of mouth, in conjunction with generally negative reviews of the film itself, signaled the end of Smell-O-Vision. A 2000 Time reader survey listed Smell-O-Vision in the “Top 100 Worst Ideas of All Time”.

https://en.wikipedia.org/wiki/Smell-O-Vision