Ashdown NFP-1

British bass‑amp brand Ashdown’s debut monitor is inspired by the classic BBC LS3/5a. How does it compare with the real deal?

If, like me, you’re a bass player, it’s likely that you’re already familiar with the Ashdown brand and its iconic but, in truth, almost completely gratuitous signature illuminated VU meter. You may even own one of the company’s backline products or have used one in a rehearsal studio somewhere. And although Ashdown do manufacture products aimed at six‑string guitar players (and, actually, a whole bunch of other often attractively idiosyncratic musical bits and pieces), it’s as a purveyor of bass backline for which the company, founded by Mark Gooday in 1997, are best known. But now, and much to my surprise, Ashdown have added a range of four active nearfield monitors to their catalogue — and they are really intriguing. The range comprises two two‑way, compact, closed‑box monitors, the larger of which sports twin bass/mid drivers in a D’Appolito format, and two similarly configured but slightly less expensive reflex‑loaded monitors.

The Ashdown monitors were announced in early 2021, but the Covid pandemic and the “frictionless trade” that’s followed the UK leaving the European Union delayed their arrival in the flesh. I’m now writing this with a pair of the smaller, closed‑box NFP‑1 models, one on either side of my DAW on my monitor shelf — illuminated VU meters and all. The NFP‑1 is a genuinely compact little monitor, not far off BBC LS3/5a dimensions. It’s built around a nominally 130mm bass/mid driver and a 28mm soft‑dome tweeter. Both drivers are sourced from Italian specialist manufacturers Sica. Sica drivers are more often seen in PA and backline products, including some Ashdown bass cabs and combos, than in studio monitoring or hi‑fi speakers, but the company are long established and generally very well respected for their transducer technology and engineering. Sica are an unusual choice for monitor drivers, but potentially a very smart one.

Driving Force

The NFP‑1 bass/mid driver incorporates a relatively conventional‑looking coated ‘paper’ diaphragm, however it features some distortion‑reducing refinements in its magnet system, and its diaphragm surround is unusual in that it comprises two small concentric roll elements rather than a single large one. As I’ve written before in these pages, the surround is where much of the heavy lifting is done in terms of the audio quality that any driver required to cover both bass and midrange frequencies can deliver. This is because the requirements of the surround at low frequencies, where it has to move forwards and backwards with as little damping and hysteresis as possible, are very different from its requirement at midrange frequencies, where it has to provide non‑reflective absorption of the mechanical energy travelling outward through the diaphragm. Getting the surround right in those terms is a challenging engineering task that demands no little skill, so the use of a complicated double‑roll surround on the NFP‑1 bass/mid driver suggests that the challenge has been acknowledged, and it augurs well.

The Sica tweeter incorporated in the NFP‑1 is a conventional‑looking 28mm‑diameter soft‑dome unit, incorporating a shallow waveguide element that will increase its axial sensitivity slightly and, at the same time, narrow its high‑frequency dispersion a little. Its 28mm diameter, rather than the more usual 25mm, appears to continue the trend that I’ve mentioned a couple of times recently for dome tweeters to get a little bigger. The advantage of a larger‑diameter tweeter is that it can operate to a lower frequency without increased distortion or thermal compression. The disadvantage is slightly more restricted dispersion above, say, 10kHz.

The crossover between the two drivers is at 3kHz with relatively steep 24dB/octave filter slopes and a little (100µS) delay added to the tweeter feed to ‘time‑align’ the output of the two drivers on the perpendicular forward axis. Electronics within the NFP‑1 are fully analogue, incorporating a Class‑A/B amplifier topology and a traditional linear power supply. The amplifiers are rated at 105 Watts for both mass/mid driver and tweeter. Intriguingly, the bass/mid amplifier of the NFP‑1 incorporates an optical compressor in series with the driver. Now, equipping a monitor with a compressor might at first thought seem a bit, well, ill‑considered, but its role in this case is simply to offer the bass/mid driver some ‘soft’ protection from overdriving. Furthermore, almost all monitors compress the signal as they get louder, in particular through voice‑coil temperature rise, so making a decision to add some more deliberate control of the process isn’t as leftfield as it might initially sound. Of course, I wouldn’t be writing in such terms about the NFP‑1 compressor if I thought it were significant subjectively, but I only felt I heard a hint of the compressor when the monitors were working at a volume level way higher than is useful in a mix context. In normal use the compressor seems innocuous.

Cabinet Meeting

Around the back of the enclosure is the usual heatsink and connection panel. Along with a mains power socket, the NFP‑1 is fitted with only analogue signal inputs. Balanced XLR and TRS jack, and unbalanced jack and RCA phono, are offered. An earth‑lift switch is provided to offer a potential fix for hum problems on the unbalanced inputs, and a gain control and balanced/unbalanced input selector switch complete the rear‑panel facilities. My usual gripe about continuously variable controls making it difficult to match the volume of a stereo pair unless the controls are maxed out is appropriate here.

The NFP‑1’s heatsink and control/connector panel.Having mentioned the rear panel, I’ll go on to describe the rest of the cabinet. Unusually for its spot in the market, the NFP‑1 cabinet is constructed entirely of Baltic birch ply with internal surfaces damped by the application of fibrous panels. The NFP‑1 cabinet is several steps above the usual plain MDF construction and, thanks also to it being divided internally so that the electronics live in a separate isolated space (generally a very good thing), it feels extremely rigid and non‑resonant. This, to my mind, is a great start. Put any decent drivers and amps in a cabinet that doesn’t play along with the music and you’ve won a significant part of the battle. The fundamentally low levels of coloration in the human voice range that a well‑behaved cabinet helps so much to realise means that the overall tonal balance of a monitor can be steered towards neutral accuracy, rather than being ‘voiced’ in order to mask or draw attention away from a particularly audible panel resonance.

The cabinet’s atypical nature doesn’t stop at its construction: it’s finished on its sides, top and bottom with what appears to be a laminated linen‑style fabric. The finish is unusual, and to my mind, looks and feels really classy. Who says there’s no alternative to black textured paint for an affordable monitor? The front‑panel appearance of the NFP‑1 is also somewhat out of the ordinary. The drivers and VU meter are framed by a painted bezel component that’s available in either black or white. Units with a white driver bezel come with a contrasting black driver panel, while those with a black bezel have a brushed‑aluminium driver panel.

BBC Sounds

I mentioned earlier that the front‑panel dimensions of the NFP‑1 are not far off those of the classic BBC LS3/5a monitor. This is actually no coincidence. Dave Green, the Ashdown engineer responsible for the conception and development of the new monitor range, is an admirer of the LS3/5a and sees the NFP‑1 as potentially able to play the same role of a tonally accurate, low‑coloration monitor in compact studio spaces.

The NFP‑1 and its inspiration, the LS3/5a.

I began to investigate the reality of Dave Green’s modern‑day LS3/5a aspirations for the NFP‑1 by capturing a little FuzzMeasure data. Diagrams 1 and 2 illustrate the basic low‑frequency characteristics of the NFP‑1, measured using a mic positioned very close to the bass/mid driver diaphragm.

Diagram 1: A close‑mic measurement of the NFP‑1’s frequency response, from 20‑300 Hz.

Diagram 1 shows the frequency response from 20 to 300 Hz and reveals that the NFP‑1’s bass bandwidth is notably extended for a small closed‑box monitor, with a ‑3dB point of around 58Hz. At 18dB/octave, the NFP‑1’s low‑frequency roll‑off is slightly steeper than the natural 12dB/octave of critically damped closed‑box systems, which suggests that EQ incorporated within the active electronics is used to modify the natural response shape of the bass/mid driver in the (approximately) 6‑litre cabinet. The extended low‑frequency bandwidth is also almost certainly partly a result of the EQ.

Diagram 2: The NFP‑1’s group delay, 30‑200 Hz.

Diagram 2 shows the NFP‑1’s group delay. Group delay is the technical term for the in/out latency that arises due to the various high‑ and low‑pass filters inherent to electro‑acoustic systems. Group delay typically both increases at low frequencies, and rises still further in response to the steepness of a system’s low‑frequency high‑pass filter (or addition of electronic and electro‑acoustic filters). Many people believe that the higher level of group delay typically displayed by reflex loaded speakers is significant in contributing to their characteristic low‑frequency subjective performance. The NFP‑1 group delay in the musically important octave between, say, 100 and 50 Hz rises from about 5 to around 14 ms. Although perfectly reasonable, and nothing to be concerned about, the group delay is slightly higher than I’d expect of a closed box monitor. The electronic EQ probably makes a contribution to this.

Diagram 3: The NFP‑1’s frequency response, measured on axis (red trace), 20 degrees above (yellow) and 20 degrees below (blue).

Diagram 3 illustrates the NFP‑1’s axial and ±20‑degrees vertically off‑axis frequency responses. The axial response is tidy and well controlled with no obvious issues. The vertically off‑axis curves show a well‑managed crossover region with the usual (and pretty much unavoidable) crossover suck‑out engineered into the below‑axis response (with the monitors oriented tweeter on top). The above‑axis response actually looks a little flatter than the axial response. I think if I were using the NFP‑1 in a studio installation that left the monitors located slightly above head height, I’d be tempted to try them turned upside down. And if a pair of NFP‑1s were to be installed in landscape mode, they would best be oriented with the tweeters inside. I also checked the NFP‑1 horizontal dispersion with FuzzMeasure but doing so didn’t reveal any surprises or problems.

Diagram 4: The on‑axis responses of the Ashdown NFP‑1 (red trace) and Rogers LS3/5a (green).

Late on during the review period I was fortunate to be able to borrow a pair of contemporary Rogers BBC LS3/5a monitors, so the final FuzzMeasure curves, Diagram 4 and 5, illustrate an axial frequency response and a low‑frequency comparison of the NFP‑1 and LS3/5a (with its front grille fitted as intended). Diagram 4, the axial response comparison, firstly illustrates the 1kHz hump that is partly responsible for the LS3/5a’s subjective character, and secondly reveals that, apart from the hump, the NFP‑1 and LS3/5a aren’t far apart in terms of axial response shape. Between, say, 1.5kHz and 10kHz the difference is typically around 1.5dB.

Diagram 5: Close‑mic measurements of the NFP‑1 (red) and LS3/5a (green), from 20‑300 Hz.

Diagram 5 shows close‑mic low‑frequency measurements of the NFP‑1 and LS3/5a. The NFP‑1 clearly offers significantly more bass bandwidth than the LS3/5a. Where the ‑3dB for the former occurs at around 58Hz, for the latter it’s 85Hz. In mix and music terms this is a significant difference, however it does mean that, even though the NFP‑1’s bass/mid driver has a somewhat greater bass diaphragm area, it will have to work much harder than the LS3/5a’s bass/mid driver.

NFP-1 In Use

And so to listening. As usual I played through the usual roster of old favourites and familiar mix sessions, and also as usual, had the NFP‑1 playing in the background in the studio room for much of the review period. Initial impressions were of noticeably extended bass bandwidth given the compact dimensions, combined with a slight midrange emphasis and marginally bright overall balance. It was also clear from pretty early on that the levels of cabinet coloration were very low, and that presentation of midrange mix detail was of a very high order. The NFP‑1 sounded immediately like a monitor that I could work with and have confidence in.

Following those initial impressions, my longer‑term feelings about the NFP‑1 changed very little, other than increasing admiration for its fundamental electro‑acoustic quality. I did make one small beneficial change to the way I had the monitors installed, however. As you’ll perhaps have noticed from the photographs, the NFP‑1 has laterally offset tweeters and I began listening with the tweeters located innermost. Swapping the monitors to locate the tweeters outermost, putting the listening position slightly off the perpendicular tweeter axis, usefully softened the slightly hard tweeter character and balance a little.

The NFP‑1 sounded immediately like a monitor that I could work with and have confidence in.

One hugely positive element of the NFP‑1 that never ceased to impress me was its natural way with voices and acoustic instruments, and I’m strongly of the opinion that the design and manufacturing effort invested in cabinet construction is an important factor in this respect. Mentioning the NFP‑1 cabinet though brings me to its subjective comparison with the LS3/5a, because a significant amount of the latter’s qualities come from its cabinet engineering. A direct comparison with the LS3/5a was both fascinating and rewarding. The LS3/5a is particularly well known for its ability to reproduce human voice recordings with uncanny realism, and while the NFP‑1 doesn’t to my ears pull off quite the same trick, its performance against the LS3/5a is genuinely very strong. It has a remarkably similar overall tonal balance and presents material with a similar dynamic character and stereo perspective — until something with significant low‑frequency content comes along, and then the NFP‑1 reaches places that the LS3/5a can’t.

Back to the NFP‑1’s low‑frequency performance, its bass is remarkably extended for such a compact monitor and, being a closed‑box design, it’s free of subjective port issues. Bass is secure in terms of pitch, and it keenly reveals the dynamics of kick drums and bass guitars, but to my ears it has one issue, and that’s volume level. Most of my listening was done at what I consider to be sensible and comfortable nearfield mix volume levels (typically floating between 65 and 75 dB SPL A‑weighted at the listening position, now you ask), but raising the level significantly with material containing substantial low‑frequency content revealed that the NFP‑1 can audibly run out of bass power handling. If pushed beyond reasonable mix volume levels, the bass performance begins to lose its dynamic qualities and to sound a little loose. While I’ve described this as an ‘issue’, in truth it’s more a consequence of the NFP‑1’s compact dimensions and reasonable price. Show me a similarly compact closed‑box monitor that doesn’t suffer limitations of low‑frequency volume level, and I’ll show you a monitor that’s much less affordable than the NFP‑1.

I had little idea of what to expect from the Ashdown NFP‑1, and it turned out to be a really pleasant surprise. Its extended low‑frequency bandwidth combined with closed‑box bass dynamics, extremely low vocal‑band coloration and a well‑judged overall balance makes for a genuinely convincing proposition. A small studio environment feeding on a diet of material that doesn’t demand huge volume levels would be the perfect environment. Just so long as you’re happy staring at a couple of illuminated VU meters...