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ReProducer Epic 55

Active Monitors By Phil Ward
Published June 2022

ReProducer Epic 55

There’s more to ReProducer’s flagship speaker than its unusual looks!

German monitor brand ReProducer Audio Labs made their debut with the compact Epic 5 active monitor around two years ago, and we reviewed it back in SOS February 2021 ( To save you the bother of sorting through your back issues, I described it as “a classy little monitor that handles extremely well the design compromises inherent to small speakers, while at the same time offering a new option in the compact nearfield category”. So, yes, the Epic 5 acquitted itself very well. The question now is: can ReProducer pull off a similar success with the significantly more ambitious midfield Epic 55?

Even though the Epic 55 is rather larger than the Epic 5, ReProducer Audio Labs haven’t dialled back the innovative and distinctive industrial take on enclosure design that was such an intriguing and attractive feature of the Epic 5. If anything, the Epic 55 is yet more dramatic, with an aesthetic that, to my eyes, looks part Tim Burton‑era Batman and part stealth fighter. The appearance is genuinely striking and it received nothing but praise from those who happened to clap eyes on it while the monitors were in my possession. The constructional materials of the Epic 55 are similar to those employed on the Epic 5 and just as impressive: precision CNC‑machined aluminium plates create the angular front panels, while the multi‑faceted enclosure is constructed from MDF panels and finished in a finely textured dark‑grey paint. The Epic 55, and Epic 5 before it, go to prove that it is still perfectly possible to develop and successfully manufacture monitors that don’t conform to the rectilinear box norms. All you need is creativity, intent, and an enclosure manufacturer willing to work outside the box (see what I did there?).

The Epic 55 in profile. Note the lack of parallel surfaces.The Epic 55 in profile. Note the lack of parallel surfaces.In addition to being great to look at, the architecture of the Epic 55 makes pretty good electro‑acoustic sense. Firstly, the multi‑faceted enclosure shape creates a multitude of non‑perpendicular angles and non‑parallel internal surfaces, which ought to help suppress internal resonance. This is especially useful on a reflex‑loaded speaker like the Epic 55, because any need to fully fill the internal volume with wadding to damp internal resonance would probably also lower the Q of the reflex resonance to the point where its fundamental worth becomes questionable.

Secondly, the Epic 55 is a D’Appolito system, in which two bass/midrange drivers (one either side of the tweeter) work in parallel right up to the crossover frequency. A fundamental characteristic of D’Appolito systems is that their (portrait orientation) vertical dispersion narrows significantly through the midrange as the spacing between the bass/mid drivers results in off‑axis acoustic path length differences and consequently destructive interference. Line‑source PA speakers control vertical dispersion through exploiting the same phenomenon. There’s a school of thought that says such dispersion narrowing can be of benefit in monitoring applications because it tends to reduce ceiling and desk reflections (or, if the monitor is mounted in landscape format, side wall reflections) in the frequency band where the ear is at its most sensitive. However, the architecture of the Epic 55 takes the dispersion narrowing effect a little further, because its two bass/mid drivers are angled inwards by a few degrees. I’ll present some FuzzMeasure frequency response data a little later in the review to illustrate the narrow vertical dispersion of the Epic 55.


I’m getting a little ahead of myself. however, because there’s some more general description that I’ve not yet covered. Rather than arriving in a simple cardboard carton with crumbling polystyrene corners, the Epic 55s are shipped in individual flightcase‑style boxes, which, while perhaps not ‘tourworthy’, are undoubtedly a big step up from the usual packaging arrangement. Within the flightcases are tightly cut foam inners that hold the monitors securely in place (and actually make it quite difficult to get them out of the box). The foam inners also incorporate compartments for the screw‑in conical metal feet and optional decoupling pad accessories. But why, I hear you ask, does the Epic 55 need feet? It does so because it is reflex loaded by a couple of auxiliary bass radiators, ABRs for short, and these are located in its bottom and top panels,. So the feet, and the 30mm of clearance they provide, are necessary because if an Epic 55 is mounted in portrait orientation, the bottom radiator requires some space to do its thing.

The Epic 55’s auxiliary bass radiator, or ABR.The Epic 55’s auxiliary bass radiator, or ABR.

ABRs perform the same function as the much more common reflex port, in that they add a tuned resonance to extend the low‑frequency bandwidth of a monitor, but they also bring a few potential advantages. Firstly, if the magnet‑less driver employed for an ABR is appropriately engineered and able to provide generous linear diaphragm movement, it should offer better linearity to higher volume levels than a reflex port. As a result, ABRs don’t suffer the ‘chuffing’ noises or the more subtle compression effects to which ports can be prone. Secondly, the lower limit of port tuning frequency is often dictated by the interrelated constraints of the length of port that will fit in the enclosure, and the diameter of the port that will allow high airflow volume before the onset of turbulence. Lowering ABR tuning frequency, on the other hand, is simply a matter of adding a little more moving mass to the diaphragm. And lastly, ABRs fundamentally don’t suffer organ pipe resonance, and they potentially reduce the leakage of midrange energy from inside the enclosure. So why are ABRs not much more common? Well, they’re physically more complicated than a port to engineer into a monitor’s architecture, they’re more complex electro‑acoustically and, of course, they’re significantly more expensive than a port in terms of both development and manufacturing budget.

Away from Epic 55 ABRs and back on the subject of the feet, one issue that I appreciated just before installing the monitors on my shelf is that the 250mm front‑to‑back spacing of the feet is greater than the depth of the shelf. The problem becomes even more of an installation snag with any inward angling of the monitors. As a result, I was initially restricted to using the Epic 55 in landscape format. Epic 55 foot spacing with regard to monitor mounting is a fundamental installation quirk and one to bear in mind if, at the end of this review, you find yourself tempted.

My fix for the foot spacing issue, and one that enabled me to revert to portrait installation format, was to use a couple of 330mm square rigid ceramic floor tiles to extend the depth of my monitor shelf. It was a solution that generally worked well, although it did reveal a further quirk of the feet in that they are not intended to offer height adjustment, so unless the mounting surface is perfectly flat (the floor tiles happened to be slightly profiled), a degree of rocking can result. The compliant rubber pads also supplied as Epic 55 accessories can help fix that problem, however.

And speaking again of accessories, there’s one more supplied in each Epic 55 box: a magnetically attached fabric grille panel that optionally covers the upper ABR when the monitors are used in portrait format. I can see why ReProducer Audio Labs felt the grilles appropriate; they protect the upward facing ABR from dust or foreign bodies generally, but to my eyes they’re aesthetically the least successful element of the design and have a hint of afterthought about them.

Driving Force

I’ve not yet written about the drivers fitted to the Epic 55 so I’ll put that right now. ReProducer Audio Labs say that rather than being off‑the‑shelf OEM items, the bass/mid drivers were developed in‑house specifically for the Epic 55. They are nominally 120mm units, fitted with an aluminium diaphragm and dust cap. Behind the diaphragm, the magnet system incorporates a T‑shaped pole‑piece to focus and linearise the magnetic flux in the voice‑coil gap. The pole‑piece also incorporates a shorting ring and copper cap to reduce flux modulation distortion and voice‑coil inductance.

TAlongside the input gain knob are HF and LF trim controls.Alongside the input gain knob are HF and LF trim controls.he Epic 55 tweeter, also a bespoke unit, is a metal‑dome device fitted with a damped rear chamber, the purpose of which is to dissipate the energy radiated from the back of the diaphragm and to help lower the driver’s fundamental resonance. Lowering the fundamental resonance of a tweeter is useful, because it keeps that resonance away from the crossover region. And speaking of the crossover, it’s located at 2.5kHz, with relatively steep 24dB/octave filter slopes (the ability to implement steep filter slopes being one of the potential advantages active monitors have over their passive cousins).

The crossover is incorporated within the Epic 55’s fully analogue active electronics, and downstream of it are three channels of Class‑D amplifier power. The amps are rated at 75 Watts for the tweeter and 120 Watts each for the bass/mid drivers. The Epic 55 provides only a single balanced analogue input, on an XLR socket located on its rear heatsink and connection panel. Said panel is also home to three detented rotary knobs proving gain adjustment and low‑ and high‑frequency EQ. The low‑frequency EQ offers ±5dB adjustment in 1dB steps from 250Hz downwards, while the high‑frequency EQ offers the same adjustment range from 2.5kHz upwards. The final feature on the rear panel is a switch that engages or disengages the Epic 55’s auto standby function.

Graphic Detail

I promised to present some FuzzMeasure analysis of the Epic 55, so here goes. Diagram 1 confirms that, from 200Hz upwards, the Epic 55 presents a well‑controlled axial frequency response that typically falls between ±2dB limits. It also illustrates the effect of selecting ±2dB on each of the EQ knobs. It’s clear that both the LF and HF EQs operate over pretty wide bandwidths, all but offering a kind of EQ ‘tilt’ facility centred around 1kHz.

Diagram 1: The Epic 55’s frequency response, measured on axis and with the HF EQ turned up (green trace) and down (blue) by 2dB.Diagram 1: The Epic 55’s frequency response, measured on axis and with the HF EQ turned up (green trace) and down (blue) by 2dB.

Diagram 2 illustrates the horizontal (in portrait orientation) off‑axis frequency response of the Epic 55 at 20 and 40 degrees, and I’ve included it partly to throw into sharp relief what’s revealed in Diagram 3. First, however, the Diagram 2 horizontal off‑axis curves reveal nothing untoward or unexpected and are typical of the breed — the response starts to fall with frequency gently at 20 degrees and then more significantly at 40 degrees, with the added effect of the bass/mid driver becoming more obviously directional (hence the gentle suck‑out between 1kHz and 3kHz).

Diagram 2: Comparing the on‑axis frequency response (red) with measurements taken 20 degrees (blue) and 40 degrees (green) off axis horizontally.Diagram 2: Comparing the on‑axis frequency response (red) with measurements taken 20 degrees (blue) and 40 degrees (green) off axis horizontally.

Diagram 3 illustrates clearly the ‘D’Appolito effect’. It shows the Epic 55’s vertical (in portrait orientation) dispersion, again at 20 and 40 degrees away from the perpendicular. Even at just 20 degrees, the output through the midrange shows a distinct dip, while at 40 degrees off‑axis there’s a big hole. The hole is centred on approximately 1100Hz, which suggest that frequency corresponds to where the difference in the path lengths from the two drivers to the measuring mic is equal to half the wavelength — half a wavelength means a phase difference of 180 degrees, which will result in fully destructive interference. At that frequency, at that point in space, the outputs of the two bass/mid drivers subtract to near zero. If you do the secondary school trigonometry, that is exactly what you’ll find. The path length difference to the measuring mic works out at around 16.5cm, which is half the wavelength at 1042Hz — close enough for jazz.

The Epic 55’s on‑axis response (red), and measurements taken 20 degrees (blue) and 40 degrees (green) off axis vertically.Diagram 3: The Epic 55’s on‑axis response (red), and measurements taken 20 degrees (blue) and 40 degrees (green) off axis vertically.

There’s one more FuzzMeasure graph to describe before I move on to report on how the Epic 55 performed subjectively. The curves in Diagram 4 illustrate the result of placing the measuring mic very close to one of the bass/mid drivers and then to one of the ABRs.

Diagram 4: Close‑mic measurements of the ABR (green) and bass driver (red).Diagram 4: Close‑mic measurements of the ABR (green) and bass driver (red).

Primarily, I was intrigued to see the tuning frequency for the ABR, which can be identified by the location of the sharp suck‑out in the driver curve and the peak of the ABR curve. This shows the tuning frequency to be around 60Hz, which is slightly higher than I would have expected considering the Epic 55’s claimed low‑frequency bandwidth of ‑3dB at 40Hz. Perhaps of more interest, however, is that both curves show evidence of resonant features at around 630Hz and 900Hz. The ABR curve (green) shows the features more clearly. As the output rolls off following the 60Hz ABR peak, the curve gets slightly lumpier as bleed from the bass/mid driver begins to contaminate it. But then at 630Hz and 900Hz, two significant high‑Q resonances jump up. The features aren’t so apparent in the close‑mic bass/mid driver trace (red), but they are definitely evident in the shape of discontinuities in the curve. I repeated these measurements with a couple of different measuring setups and environments and got the same result each time, so I’m confident the resonant features are real.

I’ve illustrated the ABR response data again in the Diagram 5 waterfall plot showing how the output decays with time, and both features are again apparent. My best guess for the source of the resonant features is that they are perhaps caused by a top‑to‑bottom standing wave in the cabinet (the only two parallel surfaces of the cabinet are the top and bottom). Maybe a little more cabinet volume wadding would have helped, but of course, as I wrote a few paragraphs back, that would drop the Q of the ABR resonance.

Diagram 5: A waterfall response taken from the ABR.Diagram 5: A waterfall response taken from the ABR.

As to the subjective audibility of the resonances, they are very localised, high‑Q features and it’s unlikely that they’ll be specifically identifiable; there won’t be 630Hz and 900Hz tones audible on everything, for example. However, every monitor has a subjective tonal signature and the resonances will make a contribution to that of the Epic 55. It would be a better monitor if the resonances were dealt with, but to my mind as they stand they are primarily of academic interest. They’re not a deal‑breaker.

Listening In

And so to my subjective reaction to the Epic 55s. Although I started off with the monitors in landscape orientation, my thoughts here really refer to the much longer period of time that I used them in portrait orientation. My studio room is relatively wide, but more limited in ceiling height, so the advantage of the D’Appolito format for me is in suppressing ceiling and desk reflections. My initial feeling was of a very competent, well sorted monitor with no obvious quirks and a usable if bright tonal balance. I relatively quickly reached for the EQ controls and turned the tweeter down by 2dB.

The most striking subjective quality of the Epic 55 is its explicit, headphone‑like clarity through the upper midrange. It’s startlingly revealing of female voices, where it shows genuine high‑end monitor levels of detail and insight, accompanied by sharply focused stereo images and revealing portrayal of depth and perspective — reverb and room character is particularly well resolved. Listening to the Unthanks’ Mount The Air was a particularly revealing and rewarding experience, for example. I suspect there’s three phenomena responsible. Firstly, the inherent performance of the Epic 55 bass/mid driver appears to be extremely high (the efforts made within the magnet system to reduce distortion are probably significant here). Secondly, the Epic 55 enclosure construction is rigid and non‑resonant, and thirdly the D’Appolito suppression of midrange ceiling and desk reflections gives the direct sound more of a chance to dominate. The latter phenomenon is a somewhat double‑edged blade, however, because tight vertical dispersion does leave the Epic 55 slightly sensitive to vertical listening position. Let your head slump and some of the midrange clarity can dissipate.

Further down the midrange band towards the upper bass, the level of performance seemed to fall away a little to my ears, with a slight extra body, reminiscent of mild microphone proximity effect, becoming apparent on male voices and low‑mid instruments. It’s a minor flaw, though, and perhaps only apparent because the performance higher up the band is so impressive. I found a couple of dB attenuation on the Epic 55 LF EQ useful in my studio room to mitigate this effect, but that then left the overall balance a little mid‑prominent. I didn’t have the opportunity to try the Epic 55 with room optimisation apps such as Sonarworks, ARC, Trinnov or Dirac Live, but I’ve a feeling that the results would be particularly rewarding.

The tweeter fitted to the Epic 55 is the same device used in the Epic 5 and my thoughts on its subjective performance were much the same too. To my ears, while not delivering the ultimate in subjective detail retrieval and insight (for that you need something like the ribbon tweeter in the Mesanovic RTM10 that I reviewed in the July 2021 issue), the tweeter offers easily enough to keep the Epic 55 very much in the game as a useful mix tool. Just occasionally the tweeter made itself known through a slight thickness on sibilance (slightly ‘sh’ when it should have been all ‘s’), but, again, it’s a very mild effect and typical of many other tweeters fitted to many other monitors.

The low‑frequency band of the Epic 55 works extremely well to my ears. Subjectively it sounds as if the Epic 55’s designers chose to be relatively cautious in terms of extending the low‑frequency bandwidth, and that results in bass performance that’s accurate and informative rather than generous and attention‑grabbing. To my way of thinking, this is the right choice in terms of effective mix monitoring. And of course, being ABR rather than port‑loaded, there’s no hint of port compression or chuffing on the Epic 55. Furthermore, by not trying too hard in terms of LF bandwidth extension, the Epic 55 is able to play more than satisfyingly loud without sounding as if it has lost its low‑frequency grip on the music.

The most striking subjective quality of the Epic 55 is its explicit, headphone‑clarity through the upper midrange.

Some of the above might read as if I found the Epic 55 to be a mixed bag, but that’s not really the case. As with any monitor that’s built to a price, the Epic 55 has some idiosyncrasies, but its positives — particularly the genuinely high‑end midrange performance and well-judged, accurate bass, but also its fabulous, other‑worldly aesthetic — unquestionably outweigh any negatives. The Epic 55 is another monitor I was sorry to see the back of. And it’s another success for ReProducer Audio Labs.


If you’re seduced by the unique look of the Epic 55 then there’s an argument that it has no competition, but in a more rounded frame of mind you’d probably want to consider options such as the Dynaudio Core 7, Focal Twin 6 Be, PSI A14M, Genelec 8340A and Unity Audio Rock MkIII.


  • Detailed and informative midrange performance.
  • Great stereo imaging.
  • Well judged bass performance.
  • Unique aesthetic and great finish quality.


  • Slight low midrange coloration.


ReProducer Audio Labs surprised us a couple of years ago with the Epic 5, and now they’ve done it again with the Epic 55. It’s a unique aesthetic take on nearfield/midfield monitoring that also happens to be an extremely capable performer.


€3298 per pair including VAT.

$2999 per pair.