Assuming you use a low-resistance (think thick) speaker cable, you can get away with different lengths. An extra 15 feet of high-resistance cable could result in some FR imbalance between channels. But given that one of your runs is 35 feet, you should be using a low-resistance cable anyway.
Speaker wire - equal length or shortest?
If you have to make the choice between running wire of equal length to your speakers or to run the shortest run possible what should you do? My components are located
on the side of my listening room. The distance to the far speaker is twice the distance to the close one (roughly 35 feet vs 20 feet) What should I do? (re-locating my equipment or speakers is not an option at this point)
on the side of my listening room. The distance to the far speaker is twice the distance to the close one (roughly 35 feet vs 20 feet) What should I do? (re-locating my equipment or speakers is not an option at this point)