This series is like embarking on the Ark. Not in the sense that there is anything ancient about the microphones involved, but just that it's two of a kind each month. Two of an AKG kind this time; the new D 300 series features three mics and the D 330 BT is discussed here. Also, and going back a few years since it first became available, we have the famous D 202.

AKG's D 300 series are described as 'musician's microphones for vocalists'. Apart from the D 330 BT with bass and treble frequency contour switching, there are the D 320 B with bass only switching and the plain D 310. The latter is cardioid in pickup pattern whereas the former are both hyper-cardioid. The D202 has indeed been in the AKG range for many years, in fact I get the impression that they have tried to 'phase it out' having produced a smaller version, the D 222, but it seems that demand prevents its demise. It is a unique cardioid having two moving coil transducers, one for low frequencies and the other for high frequencies — sort of loudspeaker woofer and tweeter in reverse. A three position bass roll off switch is provided. There is a further two-way microphone in the AKG range, the D224.

I am trying to make these reports essentially practical, emphasising the user aspects. Where possible, I try to involve them in the activities current at the time. This latter aspect proved possible this month as we shall see. Apart from that, I start by lining up the pair specific to each report with two other mics, to maintain contact with the wider mic world, and subject each in turn to a variety of sound sources and even abuses, recording the results at 15 ips with Dolby A on a Revox B77.

To deal with the common aspects first. Both are Cannon plug equipped and can be used balanced or unbalanced, depending how the connection is made to the amp or mixer. In current parlance both are 'low' impedance (300 ohms) requiring connection to pre-amps with an input impedance three to 10 times that figure.

AKG D202

I've owned a pair of these fine microphones for half a dozen years or more. It was, in fact, these which brought home to me the need to buy quality at this vital start of the recording chain. Since then I've added the superb AKG C414 capacitors, various Calrec capacitors, and have access to that ultimate in mic technology, the Calrec Soundfield. Initially I used the D202s as crossed pairs, and things were such a step forward over the cheapies I'd been using that the memory of the improvement is still with me. Now the D202s are regularly used as solo reinforcement in classical orchestral and choral recording, infill mics in brass band sessions (euphoniums always face away from the main crossed pair!), bass drum miking in multi-mic pop situations, and up to now for the overdubbing of the vocals in that field.

In the basic test line-up I took the opportunity to add one of my long-standing D202s. This was to find out if any noticeable differences could be heard. There were none! Actually it is difficult to know just how 'new' the test sample is as it did not carry a serial number. Years ago the mics were supplied with machine run individual response curves and it would have been nice to see the curve for the test sample, but there was'nt one in the carrying case. I assume they are still usually issued?

As indicated earlier I have frequently used a D202 for vocal overdubs. This I would do at some 18 inches as I basically do not like overclose miking. The opportunity arose to invite Anita and Chris of 'The Crew' to come along and try the mics in the test line up, by redoing the vocal overdubs to the backing tracks still on the shelf. I can now say that at the rather dry acoustic of my treated listening room the need for a 'vocal' mic instead of the 'flat response' type was very evident. In fact, Anita very much liked the D330 BT. Originally, however, we deliberately operated in a bright acoustic for the overdubbing, and this brings out a point I can't help repeating — a given mic's on axis and off axis characteristics will affect the detail nature of the sound acquired. So in a way, I say what price copious published response curves? They cannot do much to really inform one how a mic will sound — there is only one real way, use the thing. It's even more difficult for someone attempting what I am doing, and I am not sure that response curves would assist.

Back to the D202. The mic does not have the usual proximity effects of directional microphones; the sound character does change close to, but there is not the bass rise normally experienced. Could be due to the dual moving coil design and the long, resistance terminated path behind the low frequency unit. Some EV mics are similarly arranged and they have reduced proximity effects.

AKG D330 BT

I partnered this with the Beyer Soundstar Mk II from a previous survey so as to retain my bearings. It is obvious that the AKG hasa more forward vocal presence; this at the minimum setting of the three available. The response should not be seen as treble lifts but as broad peaks between about 3kHz and 10kHz. The switch indications might indicate the former, as can be seen in the mic's photograph, but then it would be difficult to show the true state. The mic is versatile in the bass region also, as there is a similar three-position switch operating in this area. Its purpose is to cancel the proximity rise of close usage, and this it does in its mid position, but I find the cut overdone in the third position. Somewhat like a telephone call in sound in my view! I certainly am cheered to find that the subjective results tie in very well with what I would expect from the curves on AKG's user instructions. The third switch position curve is already some 4dB down at 1kHz, and it certainly sounds like it with a noticeable reduction in signal level.

As mentioned earlier, Anita Tedder of The Crew was taken with the D 330 BT. She and Chris offered some pointers on the design features of vocal mics from their stage performance point of view. Mesh headed mics appeal, and preferably these should be silver coloured as it greatly helps in finding the right place to sing to when faced with the glare of the stage lighting. Also the tapered body shape of many vocal mics meets with their favour. The AKG D330 BT mic has a tapered body and silver coloured mesh head!

Some of the AKG booklets are full of great detail on mics in general and their individual designs. Perusal tells me that the D330 BT has 'two counterphased acoustic transducers: one receiving sound: the other picking up impact and handling noise only'. Sounds like a good idea, so I set about comparing the handling noises of all the recently surveyed mics. First of all I made sure that the mixing desk sensitivities were adjusted to give similar acoustic signal levels, and then a 'standard' handling sequence was devised. The AKG comes out way ahead of the rest with some 15dB improvement over the average, and some 10dB over its nearest rival, the Calrec CM656D.

Quite evidently the AKG D330BT has had a lot of thought put into its design. The styling involves circular rings behind the mesh head which are part of a necessity — they-conceal the opening to the diaphragm rear common to all cardioids. The top ring unscrews allowing easy dismantling, down to the plug in transducer assembly. The stand clip supplied looks and feels indestructible, it being made of a hard yet flexible 'rubbery' plastic.

Overall I can predict the D330 (and the others in the D300 series) becoming as long lived and respected as the D202 has become in its continuing lifetime.