When selecting a phono cartridge for a given model turntable, it is important to select one that is a good match for the tonearm it will be used on. Some criteria to consider during the cartridge selection process are more obvious than others, and perhaps the most often overlooked of these is cartridge compliance. Compliance (think of compliance as being the inverse of stiffness) refers to the springiness of the suspension system that is attached to the stylus cantilever at the cartridge end of the cantilever. In addition to holding the cantilever in place securely and at a predetermined angle, the suspension system performs additional crucial functions: It supports the weight of the cartridge and associated tonearm, it holds and aligns the moving magnets or coils which are part of the signal generating system, and it manages the rapid movement of the vibrating stylus at the record end of the cantilever. The stylus suspension system must be firm enough not to collapse under the weight of the cartridge and tonearm, but at the same time be compliant enough to allow the stylus to respond quickly to the widely varying audio signal embedded in the record groove walls, then return to its resting position once that signal has passed. The complementary compliance of a stylus suspension system works in unison with the effective mass of the tonearm to help the cartridge trace the signal accurately, while subjecting the stylus and record to the least amount of wear.

Cartridge compliance is also a determining factor in what the resonant frequency of the tonearm/cartridge combination will be. Some of the vibrations from the vibrating stylus assembly will reach the tonearm/cartridge assembly and cause it to resonate, or ring. This resonance occurs within a narrow band of frequencies, but it is important to manage where this band of frequencies falls. If the resonant frequency of the system happens to fall within the same range as some outside influences such as turntable rumble or footfalls, which we cannot manage, a large rise in amplitude (volume) at those frequencies may occur. This rise in amplitude can colour the sound of the music and/or affect the tracking performance of the tonearm/cartridge assembly. The preferred resonant frequency range is from 8 to 11 Hz, with 7 to 12 Hz being the absolute limits. Footfalls usually occur around 6 Hz. Carefully matching a cartridge’s compliance to the effective mass of the tonearm it will be used on will ensure that the resonant frequency of the combination falls within the acceptable range. There are various formulas for calculating the resonant frequency, but we recommend using the Cartridge Resonance Evaluator, available online at vinylengine.com. Knowing some of the general specifications for your tonearm and the cartridge you are considering will help you determine which cartridge models are suitable matches for your turntable.

Begin by entering the Tonearm Effective Mass in the box on the Cartridge Resonance Evaluator. Note that this figure should include the mass of the headshell, but not the cartridge. If the effective tonearm mass figure for your tonearm includes the mass of a cartridge that may have been provided with it, simply subtract the weight of the cartridge and any mounting hardware associated with the cartridge from this figure to determine the effective mass of the tonearm with headshell alone. Click Submit. Next, in the table that appears, locate the row that represents the compliance of the cartridge you are considering. Note that this calculator uses dynamic compliance measured at 10 Hz in its calculations. Some cartridge manufacturers, including Audio-Technica, measure dynamic compliance at 100 Hz. Compliance at 10 Hz will be higher. To use this calculator, multiply compliance at 100 Hz x 1.7 to convert it to compliance at 10 Hz. Next, find the column which represents the weight of the cartridge plus the associated cartridge mounting hardware (we figure half a gram for 2 screws with nuts). The resonant frequency for this tonearm/cartridge combination will be found where the row and the column intersect.

For example, we have a tonearm with an effective mass of 13 grams including the headshell. The cartridge, including the mounting screws with nuts, weighs 9 grams. The compliance of the cartridge is 10 cu @100 Hz, so we multiply 10 cu x 1.7 to find compliance at 10 Hz, using the result, 17 cu, for our calculation. The resonant frequency of this tonearm/cartridge combination is found where row 17 and column 9 intersect, and it is 8 Hz. This cartridge is a good match for this tonearm because the resonant frequency of the combination falls within the preferred resonant frequency range of 8 to 11 Hz.

If you have any further questions about matching a cartridge to your turntable, please contact us.