So I took my girls 09 sv to the mechanics because when we start the car we hear a consistent noise coming from the pulley area. He says he checked all of them
and they are spinning fine so drive it until it breaks. We changed the belt and the same thing is happening. We went for a drive, she took hers and I took mine. As she accelerated I could hear it get louder as her speed increases and got slower and quieter as she slowed down. I’m taking a guess that the mechanic just didn’t know what he’s talking about or the job was too much for him to handle so would I be right to change the tensioner and idler pulleys or does this sound like a different issue? Thank you

 

Some basics we have found over the years.
1.) OEM belts are quiet and stay that way. Others get noisy quickly.
2.) The tensioner spring gets weak over the years
3.) Idler pulleys are easy to replace
4.) Noise has many different "sounds"

To answer directly, it could be the pulleys, but it could also be the Power Steering Pump, AC idler or even the Alternator. But...you mention the sound changes with SPEED not RPM. This leads me to think it is more around the wheel bearing or half shaft or even something stuck in the wheel well or even a bad tire.
If it is pulleys or belt related, you will hear it change with the car parked and revving the engine.

 

I think the Lt. summed it up well. If anyone knows the 7th gen, it's the Lt., he has taken his to the moon and back, in miles, literally.

 

Thank you, I ended up spraying the upper idler pulley with a bp blaster lubricant and the noise stopped so I replaced the upper idler pulley took about 15 minutes