Purchased this sat nav a week ago. Trouble is that the voice level even on 100% is really low. Has anyone else had similar trouble? Last tom tom was loud and clear. Sounds as if on 10% but is on maximum. Tried different voices no difference. This is a real nuisance as my old tom tom was replaced as the sound vanished. Got this model as wanted something simple and similar to last one. Would appreciate any help on this.