A team of researchers have tested their tractor beam on beads up to five millimetres across. You also don't need speakers on all sides, which is good because there's no point in holding something in sound waves when you've trapped it in speakers first. They have tested there design from 30-40 centimetres away. They can hold and manipulate the beads with it. They're design was based on a similar experiment done in the University of Dundee. However their design could only pull an object towards the source of the sound.
A group of researchers in the University of Dundee have found a way to make sound wave turn a wheel, making a sonic screwdriver. This could be very helpful for hospitals doing ultrasound scans for example if they needed to get through the skull they would be able to be more precise and accurate. Sadly it can't fight Daleks yet but it still is one step more to making science fiction, science fact.