The function of a turntable is to
To achieve this
The function of a tonearm is to
Support the cartridge at the correct height and angle so as to allow the cartridge to track in the centre of the groove all the way to the centre of the LP maintaining that correct position.
To achieve this many obstacles need to be overcome
As one can see from the aforementioned, the functions of a Tonearm is not such a simple job.
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Irrespective of the type and size of your main speakers, a Velodyne Subwoofer, or better still a pair of Velodyne Subwoofers will give you an extra octave or two of base.
The latest range DD Plus Subwoofers are the most accurate transducers I have heard. Fully computer controlled, the owner for the first time will hear a true flat response from 20hz from his/her system. Be aware once you hear a true flat response you will not be content with other systems.
There is a Velodyne Subwoofer to suit all requirements and budgets.