AKG microphones are among the most respected and widely used in the field of professional audio, and there can be few, if any, studios that do not use some models from their extensive and varied range. The D202 and D224 reviewed here, are high quality moving-coil, or 'dynamic' mics, with a cardioid pick-up pattern and extended frequency response.

Both these microphones use the 'two-way' technique developed by AKG as long ago as 1964, in which separate transducers are used for high and low frequencies, the outputs of the two elements being phased together by a built-in crossover network. As in a two-way loudspeaker design, this enables the transducers size to be optimised for the particular range of frequencies that it is intended to handle, resulting in a large diaphragm for bass frequencies and a smaller unit for high frequencies.

Operating on the 'pressure-gradient' principle, which exposes both sides of the diaphragm to sound pressure in order to achieve a directional effect by various phase cancellations, these models have additional rear ports or openings, near the base of the microphone body which provide a long low frequency rear sound path to eliminate proximity effect (the rise in bass response normally exhibited in close-up use of a cardioid mic). A well controlled cardioid pick-up pattern is produced, in which the frequency response is independent of working distance, and off-axis colouration is minimised.

D202E1

The D202 is quite a large microphone, measuring 8½" in overall length, and just over 2" in diameter at its widest point. The majority of the tapered body is made from a tough, rigid plastic material, but the mic has a distinctive appearance, largely due to the striking design of the rear sound entry slots protruding from either side of the metal base section, which also houses the XLR output connector and a recessed response switch. The diaphragm assembly is protected by AKG's very tough, but acoustically transparent 'sintered bronze' grille material, which is finished, like the body, in a non-reflective black.

Within the two-way transducer system, the low frequency diaphragm handles only the 20 to 800 Hz region, while the high frequency unit mounted in front of it, takes over from 800 Hz up to the nominal 20 kHz upper limit of the response. The design utilises a hum-cancelling coil to reduce external field interference. This is an additional coil, similar to the diaphragm coil, but wired out-of-phase; interference is picked up equally in both coils, but then cancelled out by the opposite phasing. A three position bass-cut switch is also featured, offering 0, 7 or 20 dB of attenuation at 50 Hz, to assist in reducing handling noise and other unwanted low frequency sounds.

Neutral

Subjectively the D202 has a rather 'neutral' tonal character, with no particularly prominent mid-band colourations, and a response that seems well extended at both extremes, but particularly smooth at low frequencies. The mic is well suited to a wide variety of applications; the BBC, for example, uses 202s extensively for speech pick-up, while in recording studios it is frequently encountered in use as a bass drum mic, where the smoothness of the bottom end of its response assists in achieving a 'tight', well controlled bass drum sound. The absence of any proximity effect is also useful in this application, as the bass response does not alter when the distance between the mic and the drum head is changed, so it's easy to experiment with different mic positions inside or just outside the bass drum.

The specified sensitivity, although not particularly high at -76 dBV, is about average for a mic of this type, but the 202 can withstand up to 128 dB SPL (sound pressure level), so close-miking of most sources will cause no problems.

Applications

The D202 performs well in all the areas where dynamic mics are traditionally preferred, such as close-miked drums, percussion and amplifiers, but it can also be used to good effect in the recording of brass and reed instruments, or the larger stringed instruments in multi-mic orchestral sessions. A wide-range dynamic, like the 202, can sometimes be usefully employed in preference to a condenser mic, for situations where the natural transient and frequency response of the condenser might result in a sound that is too 'hard' or 'brittle', such as with some types of tuned percussion (notably vibes) and with certain brass instruments, where overemphasis of upper harmonics, caused by close-miking, can cause much of the 'warmth' of the sound to be lost.

Although it is sometimes criticised as having a rather characterless or unexciting sound, I have always found the D202 to be a most useful and versatile mic, with a response that is well suited to many practical recording situations.

Interestingly, AKG once considered dropping the D202 from their range, and the model disappeared from their catalogues around 1980. The more expensive D224 was thought to offer a similar, but superior performance, while the D222, another 'two-way' design, was available at a more competitive price. However, the D222, despite a styling and finish that give it the appearance of a scaled-down 202, is not able to offer the same level of performance. The D202 continued to be in demand and has since been fully restored to the range.

D224E

The D224 has a rugged, all metal tubular housing, 7⅝" long and ⅞" in diameter, which is finished in an attractive, non-reflective silver, described by AKG as 'satin nickel'. Like the D202, this model is a two-way moving coil design, with separate transducers for high and low frequencies. It has a cardioid pick-up pattern, with a well maintained off-axis response, and no proximity effect, due to the distributed rear loading of the diaphragm assembly. A hum compensation coil is featured, to assist in rejecting induced interference, while mechanical noise, handling noise, floor vibration etc, or unwanted low frequency signal components, can all be reduced by a 50 Hz cut switch, which has -7 and -12 dB positions. Quoted sensitivity for the D224 is -78 dBV, and the advised maximum sound pressure level, for a THD of 0.5%, is 128dB SPL; the unqualified frequency response claimed by the specification being 20 Hz to 20 kHz.

The specifications of the two models are so similar as to suggest that the D224 might offer little more than a cosmetic upgrade from the D202, but in fact the HF response of the newer model seems subjectively better maintained and distinctly smoother. Although the basic character of the sound remains the same, the D224 produces superior results with wide frequency range sources, being excellent on most of the smaller brass instruments, and with drum kit use being extended to overhead/cymbals, or snare and hi-hat. The overall performance could be described as quite smooth and refined for a dynamic mic, with speech and acoustic instruments sounding clean and uncoloured, and percussion in particular having a fine incisive quality.

Like the D202, some LF handling noise is evident, although stand mounted use is envisaged for most recording applications. However, the relatively low sensitivity of this type of mic might need to be taken into account under certain circumstances, and close-up working is advisable with low level sources, in order to avoid noise problems arising through excessive mic-amp gain.

The D224 shares most of the inherent qualities that have made the D202 popular in the broadcasting field, although its rather more stylish, but unobtrusive appearance suggests a greater suitability for TV work.

Rather unusually, this mic is supplied with two foam windshields; under conditions where wind noise is a problem, additional protection is needed for the rear sound entry ports located just above the XLR connector, necessitating the fitting of a windshield at both ends of the mic!

The D202E1 and D224E have low impedance (200 ohms), balanced outputs, and as usual with AKG products, the quality of construction and finish of both models is very good, the mics being supplied in a useful, rigid, foam lined protective case, with stand adaptor and individual frequency response plot included.

Conclusions

These versatile AKG models offer a high quality audio performance, suitable for coincident-pair recording or close-miked techniques, combined with the intrinsic ruggedness and user convenience of dynamic mics. While the D224 has the superior overall performance, the D202 still finds favour in many applications and might perhaps be considered more cost-effective in some situations; but both models have something to offer and would certainly make a most useful addition to any microphone collection.

D202E1 £136.50+VAT (£156.97)
D224E £198.50+VAT (£228.27).

Further details from AKG Acoustics, (Contact Details).