

After you have found that downforce and loading are correct, it still can be that the low frequencies are not firm enough and that the mid and high frequencies have a fuzzy character and lack detail and definition. Or it may be just the other way round: the sound is muddy, has a heavy quality and lacks speed.

Lightness, speed, firmness and correct tonal quality, they all depend on the right choice of arm for your cartridge. Or to be more precise: the right combination of the effective arm mass and the level of compliance of the phono cartridge, which actually is the elasticity, the easiness with which the diamond tip can be moved.

As the techniques of recording and record production and manufacturing were improving through the years and attained unquestionable heights, the manufacturers of turntables were conducting research and were designing new turntables which incorporated specific solutions in order to make the record player function in such a way that it does not interfere with the delicate signal contained in the groove.

It was more and more apparent that the isolation from the environment plays a key-role and had to be improved. Vibrations from the motor should be eliminated completely. Mechanical feedback (resonances) via floors, cabinets and racks also should be minimized or possibly eliminated completely. Hence the introduction of the floating chassis which was first incorporated in the famous Acoustic Research belt-drive turntable devised by Mitch Cotter. His construction deals with these two problems in a most effective way. The cantilever of the cartridge functions as a spring. The resonance of this spring should be in the 8 to 12 Hz. band. The suspension of the turntable should be much lower so it will not interfere with the functioning of the cartridge. The use of springs is an effective solution. The (de-)coupling of platter and arm can also be achieved by means of rubber feet instead of supple springs. Another, very popular method applied to modern turntables is the use of cones or spikes. Because of the reduced contact surface of a spike, only very high frequencies can be transmitted and low frequencies are stopped completely. With large rubber feet the coupling of lower frequencies is taking place to a certain degree only, because of the large surface, and the midband and high frequencies may be damped somewhat. The complex recorded signal is picked up by the cartridge which should always be fitted firmly at the end of the arm. Never loosen the cartridge screws or place a thin plate of rubber, metal or other material in between the cartridge and the headshell. If you do, the result will be an incorrect attack and no real transient at all. Tonearm and cartridge are to be considered as an entity. The suspension of the turntable should have a very low frequency so it does not interfere with the music. The cantilever of the cartridge also functions like a spring and (de-) couples the arm at the cartridge's end from the record, platter and base, while at the other end the arm is fixed at the pivot (arm base). A heavy object needs a strong spring. Likewise heavy arms are only suitable for cartridges with a sturdy cantilever. In other words: a cartridge with a low compliance figure needs a heavy arm in order to obtain a fundamental resonance in the region of 8 to 12 Hz.

A lightweight arm needs to be matched with a supple spring, in other words a very compliant spring which is the cantilever of a high-compliance cartridge. The mass of the tonearm can vary from 4,5 gr. of an SME 3009 III to even 38 grams of the Fidelity Research FR-66S. And the Ortofon SMG 212 for instance has such a heavy counterweight that the use with moving magnet cartridges is not advised. That arm was meant for heavy Ortofon MC cartridges for which the step-up transformer was incorporated in the headshell. These Ortofons had a low compliance. The very heavy Fidelity Research FR-66S has an effective mass of 38 gr.

With the Fidelity Research moving coil cartridge FR1-Mk3F the resonance is very low: 6 Hz. Also the FR-64(S) arm has a mass of 30 gr which is still too heavy for a Denon DL-103 In all cases the resonance of the arm-cartridge-system should be kept outside the audioband and should not be disturbed by the fundamental resonance of the suspension of the turntable. There should be a clear division between turntable, arm and audio signal.

Turntable suspension: 2 to 4 Hz.



Arm-cartridge resonance: 8 to 12 Hz.



Audio band: 20 to 20.000 Hz.

Naturally you will consult the literature of the cartridge manufacturer and check reviews and technical tests in order to find out what arm mass is advised. Likewise you will try to find the best cartridge for a given arm. And: you can measure the cartridge-arm resonance by using a test record (if you have one) and see if it is in the right region. The question remains: What is the frequency of a specific arm-cartridge-combination that makes the system sound best? Is it 8 Hz.? 12 Hz.? Or somewhere in between, say 9.4 Hz.? This you can find out by carefully listening to the tests of a special technical record, or just the music you are used to. So if the sound is muddy, has a heavy quality and lacks speed, than the mass of the arm is too high. You can try to find a lightweight headshell and see if that helps. But you probably will come to the conclusion that the only thing you have to do is to buy a cartridge with a lower compliance which is suitable for the heavy arm, or buy a lighter arm suitable for the cartridge you already have. If the low frequencies are not firm enough and they miss power, and the high frequencies sound fuzzy not well defined, than the arm mass is too light for the cartridge you are using. Try a heavier headshell or even a heavier arm. In that case the situation is better because you just have to add a bit of weight to the arm. Sometimes a little piece of metal of just one gram glued on top of the headshell can already mean a significant improvement. After adding the weight you have to adjust the downforce and the antiskating force anew. Here also listening carefully will tell you if you have to add more or less mass. Another important factor is the distribution of the mass of the arm. If you find that the arm mass should be greater you should nevertheless take care that the added weight is distributed more or less evenly over the length of the arm. If the arm is too light to match the correct compliance of the cartridge, adding a little piece of metal to the headshell will lower the resonance and can improve the tracking, and the signal will show less distortion. In this way you can optimize the quality the functioning of the cartridge and the retrieval of the signal out of the groove so that the most natural sound will be heard through your speaker systems.

Do not think it is done in a minute or two. Take your time. Because after optimization you might think you did the job, until you listen the next day and find that it needs readjustment.

Good luck and good listening.

