This month I have had the opportunity of testing two more microphones from the extensive Audio-Technica range - the Pro 5L, which is the premier model in the 'Pro Series', and the ATM 10 from the established and respected 'Artist Series'.

Cardioid

The Pro 5 is a moving-coil cardioid design, shaped along fairly traditional lines, apart from the subtle use of a slightly reversed taper close to the head, which adds to both comfort and stability in hand-held usage. A very tough wire mesh ball-end is employed, incorporating a multi-stage filter for protection against vocal 'popping' and wind noise, with both the ball-end and the mic body being finished in a functional matt black. The rugged, two-stage body is easily disassembled to facilitate servicing and repairs, although the very high standard of internal construction indicates that this should be an infrequent requirement.

A low profile on/off switch is provided, sensibly recessed, and located well down the body, away from the normal holding position. The review model is designated Pro 5 'L' to indicate its low impedance (250 ohms) output, (the high impedance version, Pro 5H, in fact uses the same microphone, but with a cable-mounted matching transformer), with the integral three-pin male XLR connector wired for balanced operation and standard phasing, with Pin 2 'hot', Pin 3 'cold', and Pin 1 ground.

Characteristics

The frequency response of the Pro 5 is specified as 50Hz to 15kHz, with a performance that offers a useful, but not excessive, degree of boost in the important upper midrange area, whilst frequencies below 500Hz are considerably affected by the proximity effect inherent in most cardioid mics. Close-up use provides the expected boost in the 100 to 200Hz bass region, lending warmth and power to vocal sounds, and complementing a rise in the presence region, around 3 to 4kHz, to maintain a reasonably balanced overall response. The high frequency area is adequately smooth for a mic of this type, and free from any serious peaks that could contribute towards feedback problems, with the response finally declining above 10kHz.

The unidirectional, or cardioid, pick-up pattern of the Pro 5 offers effective front to back discrimination, but the off-axis response does display some colouration and a noticeably narrower acceptance at high frequencies. However, this is not a serious deficiency in a vocal mic that will, of course, be used almost exclusively for close-up work.

In PA vocal applications this model produces a full, but well-articulated sound, displaying a fine resistance to feedback, with an initial onset of 'ringing' well outside the mid-band, which can therefore be more easily 'tuned out' without adverse effects, even with limited EQ facilities. Stage vocal mics are hardly renowned for their neutrality, but the design of the Pro 5 has managed to avoid most of the more offensive colourations that seriously limit the performance of some examples. The rising midrange imparts sufficient presence to give clarity and definition, but without seeming excessively hard or aggressive, whilst the degree of bass roll-off inherent in the distant response compensates just sufficiently for the excursions of proximity effect, to leave the bottom-end sounding full, but controlled.

The Pro 5 could be considered suitable for miking up amplifiers and a variety of instruments for sound reinforcement (PA), provided that the characteristics of the frequency response are borne in mind; sounds that consist predominantly of midrange frequencies, such as guitars, saxophones, and some parts of the drum kit, will be reproduced well, whereas bass guitar and bass drum really require a superior low frequency performance, and snare drum and cymbals would benefit from a smoother and more extended top-end.

Similar limitations apply to the use of the Pro 5 in recording situations with the most wide-range sources, notably acoustic piano which always tends to reveal the extent of any colouration present in a mic, best avoided. However, in less demanding applications, close-miked drums, brass, guitar and keyboard amplifiers, this model will perform quite acceptably, even enhancing some sources with a little additional 'colour'.

Under stage conditions, the integral wind/blast screen performs well, with no 'popping' being evident on explosive consonants, but as usual, the closer scrutiny of the studio environment indicated that an additional foam screen might be of benefit when recording vocals. The shock-mounting of the diaphragm is certainly adequate, suppressing all normal handling and impact noises to a reasonable level, including the subjectively more prominent upper frequency content of both cable noise and handling effects.

Sensitivity is about average for a moving-coil vocal mic, quoted at -76dB (0dB=1W/μbar @ 1kHz), equivalent to an open circuit voltage of 0.16mV for 74dB SPL, which is certainly sufficient for any of the envisaged close-miked applications.

Summary

The presentation of the Pro 5 is fairly basic, just a simple compartmented cardboard box, but in this instance, perhaps this indicates that most of the cost of production has gone into the quality of the product itself, for in suitable applications, this model gives a very commendable performance in return for its £75 price tag. A reasonably long (5 metre), decent quality XLR-F to XLR-M mic cable is included, along with a stand adaptor, making the Audio-Technica Pro 5 a well-equipped and attractive competitor in this congested area of the market.

Electret

The ATM 10 is an omnidirectional (equally sensitive to sounds from all directions) 'electret' condenser microphone, which utilises the fixed charge back-plate method of construction that has enabled the performance of modern electrets to genuinely rival that of conventional condenser systems. The obligatory, on-board, impedance matching preamp is powered by an internal 1.5V AA size battery, but the current drain of the FET design is so low that battery life is specified at an impressive 5000 hours!

The microphone's slim and elegantly shaped housing, which widens towards the head, is capped with a lightweight wire mesh grill. It has an on/off switch located at the base of the shaft, with the attractive appearance being completed by a low-reflectance metallic finish. The output is low impedance (described as "600 ohms nominal, matches 150 to 1kOhm inputs"), and balanced, with the integral three-pin male XLR connector providing compatible phasing via the accepted, pin 2 'hot', pin configuration.

An omnidirectional microphone, being purely a 'pressure transducer' (as opposed to the 'pressure-gradient' principle from which directionality is derived), presents fewer problems and requires less design compromise than an equivalent cardioid model, where the tuned ports necessary to achieve the directional characteristic can result in phase and frequency response deviations, causing an audible effect known as 'cardioid colouration'. Although this will not be evident from the specifications, it can be plainly demonstrated in a side by side comparison of similar quality cardioid and omnidirectional models, where the omni will invariably sound more open, transparent and natural.

The ATM 10 has a nominal frequency range of 40Hz to 18kHz, with a gentle bass roll-off over the last octave (40Hz - 80Hz) that effectively avoids rumble and other low frequency (LF) problems without losing any significant musical information. A gently rising response above 2kHz, also makes for enhanced clarity and presence. Proximity effect is completely absent in this type of mic, so the bass response remains constant, regardless of the working distance. However, the ATM 10 does exhibit a degree of directionality, with off-axis pick-up proving less sensitive to high frequencies, but this is to some extent a feature of all omnis, being due to the shadowing effect of the housing, which is, in practice, unavoidable.

Applications

The modern, multitrack recording technique, involving repeated overdubbing, encourages the use of omnidirectional mics, for with only one instrument usually being recorded at a time, directional discrimination is not needed in order to achieve separation of sounds. The subjectively 'cleaner' sound of an omni can therefore be used to good effect with virtually any instrument, with the distance between the mic and the source used to control the amount of 'acoustic' (room ambience) to be included in the sound.

For overdubbing lead guitar tracks, especially heavy rock solos, I find that the use of an omni, placed at some distance from the guitar amp/speaker in a good room, is the most effective way of conveying the sense of 'loudness' needed to complement the musical style. It is interesting to note how a track that contains a degree of natural ambience will always seem to sound bigger and louder in a mix than a 'dry' track, presumably due to the presence of psychoacoustic 'clues' that in some way help the brain to establish the true scale of a sound source.

Although many early electrets had severely restricted dynamic capabilities, the ATM 10 is specified as able to handle up to 125dB SPL, and certainly displayed no problems with loud amplifiers or instruments, even at close range.

Backing vocals, using a number of singers, are often more easily recorded by grouping the performers around a single omnidirectional microphone, using distance for balancing the blend of voices. It seems to produce a more natural blend of voices which require less compression, with the added advantage of reducing the possibility of an individual singer going seriously off-mike.

The smooth, open sound of the ATM 10 is well suited to any vocal or instrumental source which requires a 'natural' recorded sound, with mic placement often proving much simpler than when working with a cardioid, provided that the slight HF beaming is properly taken into account. In recording tests, brass, reed and wind instruments were all reproduced well, with notably fewer problems arising from level differences between upper and lower registers, than when directional mics are used with these types of instruments.

Lead vocal overdubbing can be performed with an ATM 10, provided that the good inherent insusceptibility to 'popping' is further assisted by an additional foam shield, to counteract the really excessive blasting that can occur with some singers. The complete absence of any proximity effect facilitates the intimate quality of very close range recording, without the unnatural thickening of the sound that this often causes. Audio-Technica's ATM 10SM package, which includes their very impressive shock-mount adaptor, and an appropriate foam popshield, might perhaps make a highly cost-effective main vocal mic for a budget multitrack facility, for I feel it would consistently produce superior results in this application, than an equivalently priced moving-coil cardioid.

Sensitivity (-64dBV, open circuit voltage 0.62mV) was more than adequate in all of the tested applications, whilst output noise was impressively low, and gave rise to no problems, even with wide dynamic range material, miked at a distance.

Summary

Given appropriate usage, this mic is capable of giving a most impressive performance, and seems to offer excellent value, when the low £59 price is taken into account. The advances that have been made in electret technology, and the inherent qualities of the omnidirectional mic, assist in making the ATM 10 worthy of serious consideration for many types of recording situation. The ATM 10 is supplied in a rigid protective carrying case, complete with stand adaptor and battery, although no lead is included with this model. A phantom powered version is also available, for those who don't like to rely on batteries, designated the ATM 10R, which will accept any level of supply between 9 and 52V, with no alteration in performance.

Conclusions

Audio-Technica mics are always competitively priced, but this cannot always be taken as an indication of limited performance, for both review models perform their intended functions most effectively, and can be regarded as offering excellent value.

Further details on the above microphones or any of the Audio-Technica range can be obtained from UK distributors: John Hornby Skewes & Co Ltd., (Contact Details).