The Way Ahead?
Ramsa's Miniature Condenser Microphones
Ramsa may not be a familiar name in the pro microphone world just yet, but engineer Dave Lockwood reckons they will be judging by their latest range of miniature electrets which includes both a headset and a mic that can handle an SPL of 158dB!
Ramsa may not be the most familiar name in the microphone world, but their newly-launched, innovative, miniature mic system may be set to change that, as recording engineer Dave Lockwood reports.
The idea of the miniature microphone is nothing radically new of course, but too often in the past their performance under demanding conditions has tended to match their diminutive stature, and whilst the benefits of greater performance mobility and reduced stage clutter have been obvious, often the trade-off has simply not been worthwhile. However, electret performance has advanced significantly in recent years, and new developments have seen a number of companies achieving the level of performance at which miniature systems become attractive to the professional user. The remarkable thing about Ramsa's offering in this field is that they have achieved this at a price that is within reach of all sectors of the market, and which should go a long way towards furthering the wider usage of clip-on miniature, and headset microphones.
All four mics in the Ramsa range are of the 'back electret' variety, in which the permanently charged element is not the diaphragm itself (as on early electrets) but the electret layer of the back electrode. This frees the mic designer to use a membrane material with more optimised acoustic characteristics. Although some prejudice still remains against what is still seen as essentially a 'budget' system, the modern electret can, in many instances, now provide a performance on a par with conventional 'true' condenser mics, at a significantly lower cost.
The four models use a physically very similar capsule, but with variations in audio performance, pre-amplifier system, and mounting capabilities. The tiny brass, matt-black finished capsule housing is only just over an inch long, and half an inch in diameter, with a very generous length of thin, fixed output cable leading to the special preamp connector. All the pre-amplifiers use standard three-pin male XLR output connectors, and feature belt-clips for mobile stage use. An ingenious mounting system is included, which features a flexible aluminium rod arrangement that can be bent, semi-permanently, to any required shape, with a miniature mic clip on one end and a heavy-duty, rubber-jawed clip for attaching directly to various parts of instruments, on the other.
The WM-S1E model is the smooth performer of the series, with a specified range of 50Hz to 18kHz. The response gently rises above 2kHz, and shelves through the upper-mid band, with a slight hump above 10kHz. The overall smoothness and extension of this response imparts a pleasing brilliance to the sound, but with none of the unnatural 'hard' quality of a typical 'presence peak' dynamic, or even some sloped-response condensers. In PA work, the absence of serious deviation in the mid band - and particularly the uniformity of the off-axis response - results in a significantly improved gain-before-feedback threshold, compared with many regular stage mics.
A high maximum SPL is specified (148dB @ 1kHz) allowing close miking of most sources. Although not specifically recommended for drums, I actually encountered no overload problems in this application, although the extension of the response and high degree of proximity effect exhibited, were in fact not always an asset - the alternative WM-S5 model seeming to have characteristics more effectively tailored to this type of usage. Cymbals and hi-hat were, however, quite excellent, with the extremely close pick-up possible giving excellent separation and undoubtedly helping to contribute towards an overall cleaner kit sound.
The smooth, extended HF region that enables the S1 to perform so well with cymbals recommends it for use in many other applications where a 'natural' sound is essential, such as acoustic stringed instruments or wind instruments. The excellent flexible mounting facility enables placements to be optimised to overcome the inherently unnatural effect of miking such instruments at very close quarters, even allowing some good results to be achieved with a violin - a notoriously difficult instrument to close mike effectively for PA purposes.
Experiments with acoustic guitar proved equally fruitful, the flexible rod arrangement making it possible to get the mic away from the sound-hole (which is not normally possible with a conventional clip-on mic), thus eliminating the unpleasant boominess associated with a very close miked acoustic guitar. My favourite placement, utilising an S1 pointing near the end of the guitar's fingerboard and an S5 pointed at the bridge, sounded stunning when panned apart and recorded in stereo, but could perhaps be considered something of an over-elaborate set-up for stage use!
As might reasonably be expected of a smooth condenser mic, the Ramsa S1 performed very well on acoustic piano, mounted just above the dampers about an octave above middle C - only I regretted that I didn't have a matched pair to run in stereo. One advantage of such a small system is that it permits, if necessary, keeping the lid closed when miking a grand piano in a band context, thus considerably aiding separation on an instrument that always causes problems in this area, both from a sound reinforcement and recording point of view.
Sensitivity of the S1 is good, quoted as an output level of -42dB (0dB = 1V/Pa @ 1kHz) and this, combined with the extremely close placements possible with this system, results in a very high output level in some applications. Bearing in mind that not all PA desks are equipped with a mic input 'pad' facility, the absence of any means of dropping the output of the pre-amp at source is perhaps regrettable, and could leave the user with an input overload in some circumstances - I certainly needed a padded input for some of the test sources.
Pre-amp output noise, which is sometimes a problem with electrets, is fortunately very low for this Ramsa model, the equivalent noise level at 74dB SPL (A-weighted) being 33dB, and with the low gain settings permitted by the high output level, pre-amp noise becomes insignificant in use.
The S1's slim, tubular pre-amp very much resembles a conventional microphone body, with an XLR connector at one end and the special 4-pin capsule connector at the other. Whilst light in weight, it seems fairly rugged, and should withstand rough treatment on-stage with no problems. Pre-amp output is a transformerless balanced system, and is, of course, low impedance (nominally 600 Ohms). Powering is by standard 48V phantom only, with no battery power facility being provided on this model, although others in the range will accept batteries or 'universal' 12 to 48V phantom.
Ignoring, for the moment, the fact that this is a miniature system, the Ramsa WM-S1 is essentially a very good sounding microphone, with a clean, open quality, and a smoothness that complements natural sound sources. It is at its best in the sort of situation where one would normally expect to employ a high quality condenser, where sensitivity and extension of response are among the most important factors. Although the physical/electronic properties and mounting facilities of this mic would certainly permit it to be used with just about any sound source, the response of the S1, unlike others in the range, does not seem to have been unduly tailored towards specific close-mike techniques, and as such is almost 'too good' in some PA applications where a more restricted response could be considered an asset.
The WM-S5 seems possibly to have been engineered to give peak performance in a more limited range of applications, rather than aiming for all-round excellence. Physically identical to the S1, the S5 has a more tailored response, slightly curtailed at both extremes, leaving a range extending nominally from 70Hz to 16kHz. The response is tilted, rising from approximately 5dB down at 100Hz, to roughly 5dB up at 5kHz, before tailing off smoothly above 10kHz. There is no presence peak as such, but the effect is nevertheless an attractively crisp, bright sound. Proximity effect, affecting mainly frequencies below 400Hz, is evident to a considerable degree, and can in fact be effectively used to 'tune' the low end response by varying the pick-up distance over a range of a couple of inches or so.
The overall response may be different, but the same tightly-controlled cardioid polar pattern as on the S1, is displayed, giving similar benefits in terms of separation and feedback suppression. The most remarkable feature of this model, however, is its specified maximum SPL figure of 158dB! In theory, this microphone should withstand close miking anything, and in practice I could find no source that gave it problems. The obvious application for this unit is in close miking drums; the flexible rod and clamp system is ideal for mounting directly onto the rim of a snare drum or tom-toms. This gives very high quality pick-up at close range, without the need for a tangle of mic stands, and with little danger of the mics themselves getting hit or getting in the drummer's way, as they are so small.
Transmission of mechanical noise by direct contact with the source is often a problem with such systems, but very little was actually evident during testing, the flexible rod possibly effectively damping mechanical shock and vibration, resulting in the particularly clean, uncoloured pick-up.
Sensitivity is again high, at -52dB (0dB = 1V/Pa), the resulting output on close miked snare drum certainly requiring the desk front-end to be protected from overload. An excellent deep, rock snare sound can be produced by very close placement perpendicular to a suitably damped snare head, with the sound able to be opened out to a less heavy quality if the mic is moved back a little, and angled slightly across the drum. The combination of two of these mics, an S5 on top and an S1 underneath, is even better, giving ultimate control over the balance of snare rattle, stick impact and thump.
Tom-toms were equally successful, with the variation in distance allowed by the flexible shafts proving an excellent innovation which enables significant tuning of the sound before touching any EQ!
The Ramsa S5 mic is certainly not restricted solely to drums however, for its response and dynamic capabilities also make it ideal for brass and reed instruments. Direct mounting onto the instrument not only gives players the freedom to move around in stage performance, but also has other more practical advantages, such as greater predictability of level due to the fixed relationship between the instrument and the mic, with no possibility of the player inadvertently going 'off-mic' at vital moments. In a large horn section, separation too would be considerably aided, giving immense benefits in the overall controllability of the sound.
For 'personal mic' use in this way, the user would presumably normally be expected to wear the pre-amp via its belt-clip. However, the very long (3 metre) length of thin, flexible cable leading to the capsule itself proved something of a nuisance, being susceptible to tangling, and the excess always needed to be carefully wound up and 'lost' somewhere on the wearer. As drum overhead use is perhaps the only application that could conceivably require the pre-amp to be mounted over 9-feet away from the capsule, a much shorter, perhaps even a miniature coiled cable, might have been a better idea, with the longer cable available as an accessory only when needed.
The pre-amp/power supply offered with the S5 appears to be identical to the S1 system, and similarly requires a full 48V of phantom power, offering a transformerless balanced output at 600 Ohms nominal impedance.
Ramsa's WM-S2 mic could perhaps be construed as being the 'budget' model of the range, for it is a little cheaper, and slightly under-specified in all departments, but in practice, it too has its specific areas of use.
Although the capsule appears externally identical to the others, the S2's pre-amp is a small, lightweight, rectangular affair with an XLR mounted at its base and a battery compartment that slides open to accept two AA size 1.5V batteries. Selection of phantom or battery power is automatic, with phantom taking priority, and the XLR incorporates a microswitch to disconnect the battery supply when not connected, thus, avoiding any possibility of unnecessary battery drain when not in use. A battery life of around 200 hours can apparently be expected when standard batteries are used.
The S2 specification states a frequency range of 120Hz to 15kHz, but in fact the response tails off considerably below 200Hz, and after shelving above 1 kHz, declines beyond 8kHz. However, in some PA applications this type of response can be exactly what is required, for the inevitable boosting of low frequencies provided by proximity effect in close mike placements, restores the bottom-end to something more closely approaching a flat response, whilst discriminating all the more effectively against spill from other more distant sources.
The S2 has been specifically designed for use with brass instruments such as trumpets and saxophones, and in practice seemed very well optimised for the reproduction of this type of 'midrange' instrument. Both the warmth and natural presence fundamental to the character of these instruments is retained, in spite of the close range pick-up.
Leaving aside the desirability, or otherwise, of the miniature clip-on mic, in this type of application I found the Ramsa WM-S2 undeniably subjectively preferable to the sound of any equivalently-priced conventional dynamic stage mic. If you happen to be already sold on the advantages of a miniature system, then this quality of sound is a bonus, and certainly makes this unit an extremely attractive proposition.
Quoted sensitivity is slightly lower than the other models, at -56dB (ref 0dB = 1V/Pa), but for permanent close-up use this is insignificant, as self-noise is also low, at 35dB (ref 74dB SPL) making for quiet operation at normal gain settings. The polar pick-up pattern is again impressively tight, the practical effect of this being evident in a uniform rejection of feedback at all frequencies and all angles ie. no nasty surprises when you walk in front of a monitor cab.
The price of incorporating battery power is presumably evident in the reduced maximum permitted SPL, specified at 138dB, although for the type of usage envisaged this is really quite sufficient. The S2, in fact, proved perfectly capable of use with drums and other percussion instruments, so perhaps only a snare drum and extremely over-the-top guitar stacks ought to be avoided with this highly cost-effective system.
The WM-S10 is an example of the currently fashionable headset microphone, and is therefore optimised for vocal usage. Apparently employing a pre-amp both physically and electronically identical to the S2, the capsule is located on the end of an unobtrusive adjustable arm, which is in turn mounted on a very lightweight 'open-plan' headset. A pair of very thin metal bands link the two small, adjustable, cushioned dummy ear-pieces, which are in fact designed to rest just above the ears. Apart from the sound, the vital thing about headset mics is that they should be comfortable and above all not fall off! This one could certainly be adjusted to feel secure, and reasonably comfortable, and although by the end of a long rehearsal I was glad to take it off, it is certainly a vast improvement on previous ones that I have tried. If you have a genuine need for this sort of thing I am sure that any minor discomfort would be more than offset by the benefits of the problems it solves. For multi-keyboard players, drummers, or even extrovert guitarists, headset mics like this have to be the way ahead, both for convenience and enhanced stage mobility.
Although a miniature foam pop-shield is provided with all the models, this was the only application in which I found it necessary to use one. Popping and blasting on vocals was quite severe without the shield, and to some extent with it in place. The addition of an extra shield over the top of the one provided alleviated the problem completely, but in normal PA usage would probably not be necessary as all but the most serious popping tends to get lost in the context of the overall sound of a live band.
The frequency response of the S10 headset system closely resembles that of the S2, and utilises in all probability the same capsule. Used very close to the mouth, proximity effect boosts the lower frequencies considerably, giving the artificial depth and warmth that singers tend to look for and expect in a vocal mic. The rising midrange and tailed-off bottom-end of the intrinsic response prevent the sound becoming unbalanced and muddy however, and the S10 in fact produces a surprisingly natural and well-articulated vocal sound, with a pleasing openness and clean quality that sets it apart from a typical dynamic vocal mic. I found the ensured permanent close proximity to the singer's mouth enabled gain settings to be more easily optimised, for with consistent output level guaranteed, less reserve gain is required, and feedback, already well-controlled by the tight polar characteristics of the mic, is thus further suppressed.
Sensitivity, quoted as -56dB (0dB = 1V/Pa), is more than sufficient for the envisaged close-to-the-mouth operation; the 35dB SPL (equivalent noise level at 74dB SPL) noise floor still leaving dynamic range in excess of 100dB. The maximum input SPL is a respectable 138dB for this model, and no problems were encountered in this area during normal vocal usage.
One of the less obvious advantages conferred by the usage of miniature headset mic seems to be a significant reduction in the pick-up of unwanted sounds when not actually in use for vocals. The enormous difference in spill level between an untended open vocal mic standing at the front of the stage, compared to a personal headset mic, can presumably be explained by the effect of the wearer's head permanently shielding the live side of the mic, even when not in use.
The WM-S10 headset mic can also be used in an innovative approach to miking instruments such as harmonica and flute, and for this purpose it has been made possible to mount the microphone arm on either side of the headset - a thoughtful touch.
All the Ramsa mics, except the cheapest of the four - the S2, are supplied in attractive, foam-lined rigid protective cases, and all except the headset system come complete with a full set of mounting accessories, including replacement aluminium rods which presumably have a finite life in use. A three-stage miniature boom arm, with a standard mic-stand thread on one end and the Ramsa mini mic adaptor on the other, is available as an optional accessory, and could certainly prove useful for hi-hat or drum overhead use where there is nothing much to clip onto.
The Ramsa miniature microphones proved able to perform to a very high standard in a wide variety of situations, and whilst the S10 headset and S5 seem obviously engineered to give peak performance in specific applications, the S1, regardless of its size, could certainly be regarded simply as a versatile, high quality, general purpose condenser mic.
I am sure that the extremely competitive pricing of this range will assist in overcoming any prejudice against an unfamiliar brand name and a concept that is only just beginning to gain widespread acceptance.
Although microphone choice so often tends to lead towards the familiar, with products of this quality, I would expect to see the Ramsa name rapidly become firmly established in this field.
RRP inc VAT: WM-S1 £109-99; WM-S2 £89-99; WM-S5 £119.99; WM-S10 headset £119.99.
Details from Ramsa stockists or from Panasonic/Technics UK Ltd (EMID), 300-SI 8 Bath Road, Slough, Berks SL1 6JB. Tel. (0753)34522.
Gear in this article:
Review by Dave Lockwood
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