No, Digital servos are very noisy under load. This is common and causes no problems or harm other then to your nerves. There are a few ways around this. You can use analog servos that run very quiet, add a servo helper to keep the load on the serve down (a simple spring works nice) or wrap sound proofing around the servo like Dynamat/ sound proofing wrap. I've used Dynamat and this works great.

It's possible that the servo is attempting a load that is heavier than it's designed for. Over time it may fail. Can you lessen the load or use a stronger designed servo ?

Well it's a pretty light light, a little plastic piece and another servo. Can a servo carry its own weight?

As @dschulpius has more experience with these servos than I do it appears that your servo is working as it should and it can support its own weight. Most pan and tilt cameras have a similar arrangement.

Well, Robot-Doc could be correct also. If your servo is overloaded it will fail. Also, I'm no expert. This is just what I have read in this and other forums. Just passing along learned info with a tad of personal experience behind it.

I did add a helper spring to my High Power Servo. It's lifting about 15 lbs and it stopped buzzing.

Thanks Dave!....Helper spring or bungee cord ! ..and you can measure the torque with a SCALE...fish or DIY.

I'd go with analog servos for shoulder joints.

Near all servos are loud... It's how they work - and you'll never really be able to stop it. Unless you wrap it in some sound dampening material.

Servos are loud because of their design. A servo is a little motor. And the little motor has gears. The gears add torque to the motor's output. If you turn the motor a few rotations, the output shaft of the servo will turn a tiny little bit. This allows the servo to move heavier objects with precision. The servo circuit knows what position the servo is in by a little potentiometer. When the output shaft moves, the potentiometer does also. The EZ-B sends a signal to the servo and tells it what position to hold the potentiometer in. When you apply load to the shaft, the potentiometer notices and sends a pulse to the motor. The motor moves to attempt and hold the position. The motor will move back and forth rapidly to hold the position.

And voila, your buzzing noise