Compliance

Phono Cartridge and Tonearm Matching

MC Phono Cartridge Compliance

What is Compliance?

Compliance in phono cartridges, is a measure of the stylus' (cantilever) 'flexibility' or 'softness' of the suspension. It's a way to see how easily the stylus responds to record groove undulations.

Cartridges with higher compliance will track record grooves more accurately allowing for distortion free playback even with a low tracking force. Often referred to as low tracking force cartridges, high compliance cartridges are now quite common, with a typical tracking force of approximately 2 grams. Dynavector's phono cartridges are designed with this standard in mind.

Compliance in Dynavector Phono Cartridges

There are two primary methods when measuring a phono cartridge's compliance, static and dynamic.

Compliance in Dynavector is measured statically, a method that sees how a stylus deflects in a static (0Hz) state. On the other hand, dynamically measured compliance is a method that sees how a stylus moves in response to a vibrating force of either 10Hz or 100Hz. Since the stylus' (cantilever) vibrational characteristics change with frequency, the values will differ by method.

What is the Ideal Compliance Value

Unfortunately, there is no single specific ideal value but in Dynavector we believe that a compliance value between 10–15mm/N is a good range that will match well with most tonearms. Historically, during the peak eras in the 1960s and 1970s, there was a perception in the market that "higher compliance should be better". However, it is now apparent that the most crucial factor is finding the right balance (matching) between the flexibility (compliance) of the phono cartridge and the tonearm with careful calculations. Thus, modern cartridges now opt for a more moderate compliance rather than extreme high levels.

Phono Cartridge Compliances when Matching with Tonearms

Lowest Resonant Frequency (\(f_0\))

One important indicator that you must consider when matching a phono cartridge and tonearm is the lowest resonant frequency (\(f_0\)). It refers to the frequency at which a cartridge and tonearm will most likely vibrate. It's a crucial value for you to understand how well your system will reproduce low frequencies and how well the cartridge matches to your tonearm.

This is a physical property that can be calculated based on the effective mass of the tonearm, the mass of the headshell (including screw and washer), the mass of the cartridge, and the compliance value of the cartridge.

Even if you are unfamiliar with the term "lowest resonant frequency (\(f_0\))," you may have heard general guidelines such as "light tracking cartridges should be used with low mass arms and heavy tracking cartridges should be used with high mass arms," or empirical knowledge such as "heavy tracking cartridges require high mass arms to reproduce low frequencies."

Effective Mass of a Tonearm

Unlike the total weight of a tonearm, effective mass is a value that represents the inertial mass (ease of movement) of the tonearm during operation. It is a crucial factor that influences how a tonearm responds to the vibrations of the record groove.

To put it simply, if you gently but quickly move the finger lift of the headshell up and down or side to side, you can feel the difference in inertia.

Effective mass is not solely determined by the external appearance of the tonearm, such as its length or thickness. It is also influenced by factors like the material and thickness of the arm pipe, bearing structure, and damping. Thus accurate measurement of effective mass requires specialized equipment.

Lowest Resonant Frequency (\(f_0\)) Calculation

The lowest resonant frequency (\(f_0\)) can be calculated using the following formula:

\[ f_0 = \frac{ 159 }{ \sqrt{ m \cdot c } } \]

\(m\): Effective mass of tonearm + mass of headshell, screw, washer and cartridge

\(c\): Compliance of the cartridge in mm/N* (Note: 1 mm/N = 1 x 10^6 cm/dyn)

159: The constant 159 is a conversion factor to Hz. Calculation derives from 1,000 ÷ 2π

In general, a phono cartridge and tonearm that gives a lowest resonant frequency (\(f_0\)) within 8Hz - 12Hz is considered an optimal match.

Calculation Example

As an example, let's calculate the XX-2A's lowest resonant frequency (\(f_0\)).

XX-2A's has a compliance of 10mm/N and weighs 9.3g. When mounted on an arm with an effective mass of 12.5g and a headshell weighing 11g the lowest resonant frequency (\(f_0\)) is approximately 8.8Hz.

As another combination example, if the same cartridge is mounted on a different arm with an effective mass of 9g and a headshell weighing 8g the lowest resonant frequency (\(f_0\)) is approximately 9.8Hz.

Both combinations fall in to the recommended range of 8Hz～12Hz, indicating a good match. However, it's important to note that the difference in (\(f_0\)) between 8.8 Hz and 9.8 Hz will result in variations to low/high-frequency responses, as well as the overall balance in sound.

Challenges of Phono Cartridge and Tonearm Matching

What happens if the Lowest Resonant Frequency (\(f_0\)) is too High or too Low?

The lowest resonant frequency (\(f_0\)) tells us the lowest bass sound your turntable can reproduce with that phono cartridge and tonearm combination.

● If Lowest Resonant Frequency (\(f_0\)) is too High

A lowest resonant frequency (\(f_0\)) of 13Hz and above will limit your turntable's ability to reproduce low frequencies, resulting in less powerful and deep bass sounds as well as reduced accuracy when reproducing large amplitude signals.

This typically occurs if a low compliance phono cartridge (a relatively stiff cartridge) is paired with a low mass tonearm.

● If the Lowest Resonant Frequency (\(f_0\)) is too Low

Since a low resonant frequency (\(f_0\)) means that your turntable can reproduce lower frequencies better you may think 'the lower the better'. Unfortunately, it's not that simple. If the lowest resonant frequency (\(f_0\)) is lower than 7Hz the cartridge becomes overly sensitive and may reproduce record warps and other imperfections, which can mask higher frequencies and introduce unwanted noise.

This typically occurs if a high compliance phono cartridge (a relatively soft cartridge) is paired with a high mass tonearm.

Other Challenges

To achieve the best possible sound quality, it is essential to match a phono cartridge and tonearm that falls in the optimal lowest resonant frequency (\(f_0\)) range of 8Hz and 12Hz.

Yet, there are still challenges when trying to achieve the optimal (\(f_0\)). For example, not all tonearm manufacturers provide detailed specifications regarding the effective mass. Another challenge comes from the fact that a phono cartridge's compliance will change due to environmental factors such as temperature, further complicating the process of matching cartridges and tonearms.

Dynavector Phono Cartridges and Tonearm Matching

Dynavector's MC phono cartridges are designed to match with most low - moderate mass tonearms. However, the optimal match can vary depending on factors such as the mass of the headshell and personal sound preferences. Therefore, please adjust the combination to suit your system setup.

You may also enjoy matching with Dynavector's innovative tonearm DV 507MkII. It is a mass-separated bi-axial inertia controlled tonearm with different effective masses in the horizontal and vertical plane. This tonearm structure allows sufficient low-frequency response and extended high-frequency reproduction with most cartridges, including Dynavector cartridges. If you are having trouble matching your tonearm with a cartridge, especially with low-frequency reproduction, we recommend the DV 507MkII.