Well-balanced

On a practical note, NAD has set the output from the FM tuner lower than from the DAB, with the latter already lower in level (at peak output) than most CD players.

Because of the compression of dynamics used in both radio systems, subjective results seem to be quite well-balanced against typical CDs.

Basic measurements of both sections suggest that technical performance is very good, though we have seen lower levels of ultrasonic output from FM tuners.

Mixed sound quality

DAB tuners vary considerably less than FM ones, and it was to the FM section that we turned first, in high hopes of hearing something revelatory. Maybe that was a high bar to set, but it's certainly true that we heard many things that we very much liked.

First, foremost and enduringly, we heard some remarkably clean radio reception. This was in part due to a decent rooftop aerial, a purchase we would highly recommend to anyone considering this or any other high quality FM tuner if circumstances permit.

Still, most tuners reviewed in these pages have been fed from the very same aerial, and in that context the M4 does stick out as one of the cleanest. Indeed, it makes a good stab with just the supplied indoor aerial, the usual T-ribbon.

FM performance

FM is capable of very good sound, but one of the toughest gremlins to eliminate is a degree of harshness, especially in built-up areas where multi-path distortion is a perennial problem.

Over the years, advances in the integrated circuits and tuner heads used in most FM tuners have helped considerably in this area, but good performance is by no means automatic. NAD must be congratulated on wringing some very fine subjective results from the components it uses in the M4.

With both BBC and commercial radio stations, we found the sound to be almost completely devoid of any such effect and, as a direct result, very informative and listenable in the long term.

Naturally, detail is well preserved in the sound because of this. Getting the ultimate in detail out of an FM transmission may be one trick beyond this model, and we do feel there is some justification left, in this parameter above all others, for the even high prices of a few dedicated FM tuners from Naim and others.

On the other hand, few of those models can manage to better the tonal balance of the M4, which is again very fine indeed. The bass is very extended, but without excess or lack of control, while treble is unconstricted: as the original designers of stereo FM realised, a band limit of 15khz is barely perceptible as a restriction if it is well implemented.

Competent DAB

Truly neutral midrange is exceptionally rare among tuners, but also hard to gauge because of the way recordings are processed. By putting into service our own FM generator, fed from a local CD player so that the reference is available at the flick of a switch, we became aware of a slight chestiness to the sound, something we've heard from many models.

However, we really do mean 'slight' and only with the most carefully prepared broadcasts on Radios 3 and 4 were we able to convince ourselves that we could pick it up in typical use and then only by listening specifically for it. To all intents and purposes, this is an evenhanded tuner, tonally speaking.

We've little to say about DAB here, save that it is clearly very competent and better than any current broadcast is likely to explore in detail.

It is admirably quiet and also well behaved, with no unpleasant surprises when re-tuning to a different station.

Cut above the rest

In terms of raw performance, the NAD M4 FM/AM/DAB tuner does not necessarily stand out from the best on offer in the sub-£500 bracket: clearly, the law of diminishing returns with tuners sets in.

But it is a very fine product and visually and ergonomically a cut above most and, of course, a perfect match to the rest of the NAD Masters range. We are happy to give it a warm, if not entirely unqualified, welcome.