It's good to know in these times of rapid technological advance that not all items of recording equipment are drastically changing their appearance as well as heightening their performance. So, alongside the hard disk recorder, you'll still find that familiar metal shell with a diaphragm mounted inside, commonly known as a 'microphone', reacting in a traditionally analogue way as its diaphragm oscillates in direct response to the sound waves hitting it. Of course, until a digital counterpart is developed (if ever), the traditional microphone is under an ever-sharpening digital focus, so it's left to manufacturers like Beyer to continually redesign within the physical confines of the microphone body to yield the optimum result.

Within these constraints, the product must naturally fulfill a particular role. In the case of these TGX microphones - the 180, 280, 480, and 580 - Beyer see them as 'sound reinforcement' mics suitable for use on close vocals and close miked instruments, positioned close to the speaker cone of an instrument amplifier.

As PA mics, the TGX range should be capable of the following:
• Rough handling
• Feedback rejection
• Ability to cleanly transduce high volume levels
• Low handling noise
• Represent the sound source faithfully

But before immersing ourselves in the details of how the mics perform, I'd like to consider the improvements Beyer have made to this long established design.

Firstly, the output level of the microphones has been increased using 'enhanced magnetic field rare earth magnets'. As the mic's signal strength is derived from a coil of wire fixed to the back of the diaphragm moving in the circular gap of an annular magnet assembly, the use of more powerful magnets helps produce more juice - or as the manufacturer puts it: "Beyer's powerful rare earth magnets... provide increased field strength of 12,500 Gauss compared to 5,000 in other mics." (The term 'Gauss' refers to the unit used to measure magnetic flux density and may be more familiar to those of you using a demagnetiser (or degausser) to remove unwanted magnetic charge from your tape recorder's heads.

The next improvement is the use of Macrolon and Hostaphan for the diaphragms - to help extend the frequency response, cope better with loud audio signals (they can handle sound pressure levels, or SPLs, up to 140dB), and enhance the transient response. The 280 and 580 incorporate Hostaphan diaphragms, and the 180 and 480 use Macrolon. The essential difference seems to be that the Hostaphan helps improve/extend the low frequency response. Beyer liken the transient response of these mics to that of ribbon microphones which, due to their design, typically exhibit both great transient and (smooth) frequency response. This leads me to think that as ribbon microphone diaphragms are amazingly thin and delicate, typically measuring a few microns thick, the new materials used by Beyer are both thin but extremely durable. Because we're dealing here with dynamic mics, instead, the inherent frail characteristics associated with ribbon mics - like sensitivity to wind noise and external vibrations - are not in any way a problem. In fact, due to the operation of dynamic microphones, their main resonance (ie. the frequency at which the diaphragm naturally oscillates) lies in the mid-frequency band and is well damped. This means that wind and handling noise, which tend to manifest themselves as low frequency rumble, are absent. The well damped mid-frequency resonance in the Beyer TGX mics simply means that the amplitude of those oscillations decays more quickly, so creating neither low nor mid-frequency interference.

The reason for striving to improve the transient response is simply because it is this reaction of the diaphragm - to accurately capture the start of the sound - that gives the sound its identity. (Transient: 'a phenomenon which occurs during the change of a system from one steady state to another.') If the start or 'attack' phase is removed from a signal, it can make that sound almost impossible to identify. (In an experiment I conducted for a cassette series called 'The Elements Of Music', the attack of two different instruments playing a note of the same pitch was removed, making it impossible to judge which was the saxophone and which was the flute!)

Thanks to those technological advances I referred to earlier, the size of the internal components have been reduced, allowing still greater scope for shock protection, which further mechanically aids the rejection of low frequency interference.

Now let's return to our earlier preconceptions of how the mics should perform, to see if they were accurate. In fact, each of the TGX mics fulfills those categories to a different level of achievement. They are all very rugged, yet pleasantly light and well balanced; their rejection of feedback is tremendous, with each mic attaining the same gain before feedback sets in (nice to know that even if you opt for the cheaper 180 and 280 models, their feedback tolerance is similar to the more expensive mics in the TGX range). One other feature which goes some way to guarding them against feedback is their polar response - hyper-cardioid, making them least sensitive to sounds approaching from the rear (ie. 180 degrees).

FIELD TEST RESULTS

None of the review mics had any problem coping with the sound levels I threw at them, and even though I didn't have the opportunity to test them in a full-blooded PA rig, they didn't at all mind being subjected to the high energy output from a 200 watt Marshall stack. I did, however, find their response a touch 'shrill' (especially the 180 and 280), but I'd rather have the option of rolling off this brightness than boosting the high frequency content of a dull signal anyday - so no complaints there, really.

Handling noise, as you might expect after all I've said, was very good. It was apparent in solo tests but negligible relative to the output level.

And so to how the mics actually sound... The 180 and 280 are similar, apart from the 280's extended bass response. Both mics seem to output a lower signal than either the 480 or 580, and therefore sound weak in comparison. The 480 and 580 give a much fuller response, with the 580 giving the clearest response - especially for close vocal work - as the more accentuated 'proximity effect' of the 480 seems to muddy the sound. This proximity effect (also known as 'bass tip-up') accentuates the bass response and, to my mind and ears, therefore gives a distorted image of the source, tending to make it boom.

I find it a little strange that Beyer are marketing this effect as a positive benefit, saying that it gives the mic "punch" and "makes a singer stand out in live performance." Personally, I find it too intrusive - and certainly in a recording environment, too many cardioid/hyper-cardioid close miked sources can definitely cloud the overall result. Of course, there's nothing to stop the sound engineer rolling off some of that bass boost, or the vocalist holding the mic a few more centimetres away from the mouth, at which point the response becomes much flatter. Interesting that Beyer don't say anything about greater clarity!

On making direct comparisons between the top and bottom of the TGX range, the 580 and 180, the latter simply doesn't get a look in - but then as the 580 is about twice the price, I'm not surprised. Beyer promote the 180 as an "affordable option for young rock and rollers," but perhaps they should also consider the education market, as the mic meets the appropriate criteria, being of reasonable sound quality, very durable, and priced right for limited budgets.

All of the mics seem suited to instrument amplification, with the 480 and 580 giving the better results. It's conceivable that the 480 and 580 could be used for studio recording of percussion instruments, for example, or for the recording of guitar amps - possibly even for sampling of high level sounds. However, I think I'd draw the line at recording vocals, as even though the TGX mics are good for the applications they have been designed for, they are no match for the smoothness of capacitor mics in this particular role (but then Beyer don't suggest they should be).

SUMMARY

So, there you have it, two very tasty mics and a couple of reasonable ones which fulfill everything they were designed to achieve. I'd definitely recommend you try out the 480 and 580 models. You'll be satisfied with the results.

FURTHER INFORMATION

Prices (inc VAT): 180TGX £98.90, 280TGX £139.15, 480TGX £169.05, 580TGX £198.95.

Beyer Dynamic GB Ltd, (Contact Details).