Acoustic Energy Pro Sub/Sat 5.1

They fit all of that in there?

by AVForums
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Acoustic Energy Pro Sub/Sat 5.1
SRP: £3,094.00
Acoustic Energy Pro Sub/Sat 5.1

Introduction

The boundaries between the disparate worlds of professional and consumer audio have been blurring for some while now. Some manufacturers have always traded on the kudos they feel they gain from their pro audio associations, whilst others barely even hint at ranges, apparently hidden from the mass market. For the most part, this is a marketing decision based on what the manufacturer believes are its core customers beliefs and, to a larger degree, whether they have a presence in both markets – There's no point in bigging up studio style sound if you don't make pro orientated loudspeakers for instance.

Then again, there has always been a certain element in the hi-fi community that, for some reason, believe that a product designed to withstand the rigours of a studio will lack the delicacy and finesse of a ‘true’ hi-fi loudspeaker that isn’t expected to play at high SPLs, eight hours a day, day in day out. Indeed the pro boys aren’t worried about fancy veneers, or speaker grills (speakers are for listening to, right?) and don’t want a speaker voiced to be pleasant, as much as to be ruthlessly transparent and as easy on the ear, at the end of the day as it was at the beginning.

It is perhaps an indication of my personal preference that I'm not sure why some would think that any or all of those qualities need to be mutually exclusive and, indeed, Acoustic Energy are one such manufacturer that doesn't appear to think this needs be the case either. Their very first product, the AE1 was a studio monitor that quickly found favour in consumer households precisely because it was a very revealing design that played 'music' and their pro and consumer lines have enjoyed the shared heritage, to a greater or lesser degree ever since.

The Pro Sub Sat package reviewed here is a fine case in point; it is first and foremost a studio mastering tool - used by such luminaries as John Olive, the sound designer of the Harry Potter, Mummy/Mummy Returns & Reign of Fire films to name a few. The fact that it is designed for the closer confines of the smaller mixing room means it will fit very neatly into the similar sized spaces of a typical domestic living room and further interest is garnered, in comparison to the previously reviewed Neo V2 domestic package, due to a fair amount of shared DNA.

Tech stuff – Pro Sat Satellites

Acoustic Energy Pro Sub/Sat 5.1

The shared DNA is principally in the driver line up of the Pro Sats. The Vifa XT-25 ring radiator tweeter and the 130mm mid bass driver are basically as described in a Neo Version 2 review, so, to cut down on repetition, I'll leave you to read that review for a more in-depth look at the drivers. It's the way they're employed in the Sats that is altogether more interesting. Even in this day and age of ever shrinking loudspeakers, the six litre cabinet (220mm x 150mm x 180mm, HxWxD) is very compact and, given the space required to actually fit the drivers, couldn't be much smaller. As it is, the tweeter is mounted in an attractive aluminium casing that protrudes above the cabinet. This rather nice detail, and the way it keys with the mid/bass driver surround, takes your eye off the fact that the otherwise very square edged 12mm MDF cabinet is finished in a utilitarian 'pro' black vinyl wrap of unremarkable construction. Internal bracing is limited to a single, vertical solid panel that seals off the rear quarter of the cabinet from the front. More on why later.

The choice of a sealed cabinet that can be much smaller than it's ported equivalent is the key here, as the Pro Sats are really designed to work in conjunction with the Pro Sub to provide real low frequency extension and, as such, simply don't need to try and squeeze mega bass output from their bijou dimensions. This frees up the sealed cabinet to major in what sealed cabinets do best; namely provide a flat phase response, free of the shifts caused by the output of the port within the audible pass band and therefore deliver a tight, transient response for increased dynamic attack and a short impulse response to deliver equally quick decay. Simply put, the point of the sealed alignment is to make the entire frequency range that the Sats cover start at the exactly the same and stop as quickly as possible once the sound does.

Acoustic Energy Pro Sub/Sat 5.1

Looking at the rear of the Sats cabinet, the reason for the separate compartment, entirely sealed off from the volume occupied by the drivers, becomes apparent. Rather than the usual pair of speaker binding posts, the rear panel is that of an amplifier or, to be precise, two amplifiers and an active crossover, for this is a true active bi-amplified speaker. That is unusual in domestic audio or, at least I feel more unusual than it should be, because it delivers some manifestly obvious benefits. To understand the benefits, you first have to understand the compromises typically endured by normal passive speakers. A passive crossover is best understood as a pair of electrical filters that are fed the same signal by your amplifier. Their job is to filter out frequencies, below a chosen point - in the case of the tweeter and above a certain point in the case of the mid bass driver, with the two resulting filter slopes crossing over at a point that should allow the frequency range to progress smoothly as possible between the two drivers. The values of the electrical components chosen are defined by the electrical parameters of the drivers, with which they work, as the two are considered part of the same electrical circuit.

The problem, and this is what makes crossover design a bit of a dark art, is that the electrical values of the driver change not only with frequency and volume, but also with temperature and, thus, a short sharp burst of a given frequency can have a very different effect on the driver to a sustained burst of the same, or even a different effect depending on whatever the other frequencies are being played at the same time. This means the combined value of the driver/crossover circuit is dynamic - never constant and thus, the effect of the circuit formed by the driver and crossover, becomes somewhat of a moving target with the phase response and distortion varying to a greater degree than that of the driver, alone, being played those frequencies without a crossover in the way. This is the first issue that an active crossover seeks to overcome because, as it is placed before the amplifier - instead of after, it is presented with the fixed load of the amplifiers input. Combine that with the fact that it is working at line level voltages, with very low current flow, and you can chose smaller components with tighter values to engineer a more precise and consistent crossover that does not change, regardless of the program or levels at which it is being played.

The amplifier is happy too, because it can be engineered specifically to meet the demands of the driver with which it is to be partnered, quite unlike a normal amplifier that has to do what it can to drive whatever speaker the end user chooses to 'match' it with. It need not be any more powerful than the driver (in a given cabinet) requires, which brings the side benefit of amplifier and driver protection - the amplifiers output can be set to prevent overdriving the driver and, likewise, the pair set to close down if one or the other exceeds pre-set thermal limits. It's normally very hard, if not impossible, to damage an active speaker. Furthermore, the amplifier matched to the load of the driver, maintains a much tighter grip over its motion - there is no crossover in the way to dilute its electrical grip on the driver. This also makes for a very efficient transfer of power from amplifier to driver as there are no lossy components in the way presenting an electrically more difficult and, therefore, thermally more wasteful barrier which tends to make active speakers more efficient. How much more efficient seems to vary depending on who you are listening to, with opinions varying from 10 to 50%. Even assuming a middle ground, for the sake of argument, actives always seem to go louder with less strain off less power than their passive counterparts. I was certainly able to drive the Pro Sats to comfortably higher levels than the Neo 1's, for instance, and whilst the latter had the benefit of over 200w per speaker from my power amp, the Pro Sats make do with a 25w amp for the tweeter and 50w for the mid bass.

The active amplifiers, in this instance, are ICE Power modules (a proprietary technology of Bang & Olufsen) that broadly fall under the banner of 'digital' pulse width modulation amplifiers. Discussion of PWM verses MOSFET Class A or A/B amplifiers could fill a website or forum in its own right (and frequently does), but one of the chief benefits, accurately claimed, is that PWM amps are typically 90% power efficient. I was slightly surprised that the rear of the Pro Sats was notably warm, even at idle, although not a great deal warmer after a good hammering. On the plus side, as I am lazy when it comes to turning things off, it meant they were generally into their warmed boogy zone pretty much from the off.

Rear panel connections obviously don't include speaker binding posts, connections to the outside world being provided by a balanced XLR or RCA phono input. There is a 3 pin IEC power socket and On/Off switch, but no auto signal sensing option. This may not matter in a commercial studio and , as mentioned, doesn't bother me much but some will quite rightly think this to be a sin of omission. Sure, you can just employ RF controlled power sockets between the wall and the power cable, but I'd like to see this domestically orientated feature added. That goes for the missing driver grill too - another feature betraying the pro-audio roots. Again, it's not something that bothers me - my two year old has been 'trained' to ignore daddy's speakers but, unlike the Auto On/Off situation, it's an omission that is less easy to overcome. That said, the Pro Sats are designed to work pretty much hard up against a wall and the base of the cabinet comes pre-drilled to accept dedicated wall mounts so, more than with most speakers, the Pro Sats - which need mounting quite high due to their short stature -beg to be wall-mounted, which may sidestep the problem to a degree.

The final piece of the Pro Sat picture is the provision of a small panel of dip switches, on the rear, that can adjust certain parameters of the active crossover. Treble can be adjusted from flat to either +2dB, to account for either an over-damped room acoustic and/or increased seating distances, or -2dB for use in the extreme near field such as a desktop computer speaker. There is also a dip switch for adjusting the low frequency response from ‘Normal’ (bottom end response limited to 90Hz) and ‘Extended’ which is the natural extension of 75Hz. AE quote the +/-3dB limits at 100Hz to 40kHz so the Normal and Extended response settings seem to assume some amount of boundary gain. The ‘Normal’ response is really a feature for use in conjunction with the Pro Sub that would typically apply to studio use, rather than the already bass managed environment of a home theatre processor/receiver, but it would have use in a pure stereo setup devoid of bass management facilities. The remaining control is a 0dB/-3dB/-6dB sensitivity switch to account for the varying output levels of mixing desks – I set it to 0dB as that worked best in conjunction with the levels of my system, but experimentation would be in order.

Although the Pro Sats could be employed ‘full’ range in a BBC LS3/5a sort of way, as the ‘Extended’ response when mounted close to a boundary isn’t bad (I measured useful extension to 50Hz in room at moderate volumes), they are really designed to be used in concert with a subwoofer, hence the accurate description of them as satellites – This is a term often misused to describe small speakers but, in fact, just means a bandwidth limited speaker and that doesn’t preclude them being very large!

Tech Stuff - Pro Sub Subwoofer

Acoustic Energy Pro Sub/Sat 5.1

The subwoofer is the matching Pro Sub, which again sports an array of features potentially limited in an HT application, I’ll run through them in a moment. The Pro Sub is, again, a sealed active design, differing slightly from the norm in employing a pair of 250mm nominal diameter drivers in an opposed push-push configuration to cancel the forces applied by the drivers to the cabinet. Oddly, given their sibling satellites lack them, the Pro Sub drivers have grills. The cabinet is again the de rigeur studio textured black, but in concert with the heavily radiused cabinet edges, and grills, the overall impression is of a very tidy and discrete 350mm cube.

Turning to the rear and the 200w (RMS) plate amp again displays an array of features with a studio bias. The usual, single, LFE input is present in both RCA phono and balanced XLR varieties but so are balanced XLR in and outputs for the five satellite channels. The reason for this is that the five main speaker channels are designed to be fed full-range to the suboofer that will then pass through the signal to the satellites, thus working as a full range speaker. In a studio where you are mixing channels as full range, this is required – you need to be able to hear and mix the entire bandwidth of each discrete channel. At home, where the bass from each channel is redirected to the sub by the processor/receivers bass management, it’s of less use. That’s not to say it’s redundant – in a dedicated stereo setup where the pre-amplifier signal is full range only, it opens up the possibility of adding bass managing to a stereo signal.

Other controls, on the rear panel, include dip switches for 0/180deg phase invert and to set the frequency (70 or 100Hz) of the low pass filter, to be used in conjunction with the corresponding filter on the Pro Sats. The continuously sweepable gain control is a tiny screwdriver adjustable affair rather than the more normal knob but, as I set this to the correct level once, and thereafter made minor adjustments to taste using the processor’s channel gains, it’s less of an issue than it might seem.

Setup

Acoustic Energy very kindly supplied enough balanced and single ended to balanced adaptor cables so that I was able to run every configuration intended and probably a few besides. I did, for the sake of completeness, run the full six cables to the sub from the processor and then connect the five satellites to the sub, as intended in its full studio configuration but this threw up two problems; one was that the space-saving advantage of loosing a multichannel power-amp from my rack was immediately undone by a phenomenal amount of cabling running around the joint. Admittedly, you would get cables custom made to your own lengths, if the system were yours and two, if you are employing an external subwoofer EQ device (as I do), you are restricted to EQing the LFE soundtrack, as the main speaker channel bass is no longer redirected via the processor's subwoofer output as it would be when setting the speakers to ‘Small’, in the processor/receivers internal settings. As a result, I rewired the satellites and sub direct to their relevant outputs on the processor, set the sub's crossover to maximum, the Sat's extension to 'Extended' and all listening was accomplished thus configured.

Acoustic Energy Pro Sub/Sat 5.1

It should be noted that if you have pre-wired your room for normal speaker cables, they are now redundant and you’ll have to work out a way of dragging through or hiding a potentially thicker line level interconnect. It’s also worth noting that you will need to have a power socket near to each speaker which through luck, rather than design, I do.

The Sats are intended to be used close to a boundary, be it a mixing desk or living room wall and, unsurprisingly, they worked best as close to the wall as three inches of XLR plug and power cable would allow. This proved quite interesting as I measured the response (as per usual whilst positioning) and, as a result of the very short reflection path from the speaker to the rear wall, the frequency response from about 300Hz down to 50Hz was staggeringly flat and once toed in directly toward the listening position, the midrange and treble response was very even too. With the sub just to the left of the front left speaker and EQ’d to take out the room’s remaining bass booms, the nett result was one of the flattest responses I’ve ever seen in my room, with a response pretty much within +/-2dB from 25Hz to 10kHz at the listening position. I don’t normally mention the in-room response of speakers but the graph displayed on my screen was so flat, it created a “What have I done wrong?” moment. As it turned out, I hadn't erred.

Whilst I left the frequency response of the three front satellites set to ‘Extended’ with treble at ‘0dB’, the rears were mounted higher overhead, toward the rear corners of my room which caused a little too much lower mid/upper bass reinforcement and a slightly dull treble. A direct radiating speaker like this is designed to be at the same height as the fronts, but my current room doesn't allow this. I opted for +2dB on the treble and the ‘Normal’ restricted bass extension setting. The result was a better tonal match with the fronts and is a trick you'd struggle to match with traditional passive speakers.

Listening - Music

If I had to characterise the sound of the Pro Sat/Sub system, I’d say that it’s one of real hear-through clarity combined with extraordinary composure, the latter point more reminiscent of a much larger speaker with a lot more amplification in tow. It was certainly an interesting listen with the Neo V2s, with which the Pro Sats share so much DNA, fresh in my memory. The presentation is so far removed as to clearly demonstrate why so much cobblers is talked about driver choice. That’s not to say better drivers don’t make a difference - it’s just that how you employ them is probably more important. Whereas the Neos had what I felt to be a well judged balanced and refined treble for their price point, the same tweeter in the Sats sounds altogether more expensive and polished. Natural levels of detail are really cranked up a notch without exacerbating sibilance through an unnatural emphasis in the frequency response. The treble just sounds altogether better integrated and composed, like a layer of excessive effort and glare has been removed. It’s much the same story with the mid-bass driver that dynamically punches far harder than it’s size suggests it has any right to and it translates to an ease and naturalness to vocal reproduction, in particular.

Sounds that can appear to be a bit edgy, or voices that have enough power to sound borderline 'shouty' turn out to be nothing of the sort through the Pro Sats. This is a quality that I’ve noted with actives before and it’s related to the advantages the active crossover brings to bear; it's possible to use much steeper crossover slopes to integrate the drivers that crucially means less output is being asked of either driver, in the part of the range where it's cone or dome breakup modes start to contribute. The result is far less distortion, at all volume levels, and it was notable how comfortable the Sats sound cranked up. Don't get me wrong, you're not going to lift the roof off a large open plan penthouse but, in the more humble confines of the average living room, the output is plenty. The Pro Sats also maintain their impressive expression and clarity at low levels. Most metal coned loudspeakers I've used seem to have a point in the volume range above which they seem to wake up. Not so with the Sats and they make for a very communicative listen even late at night with the family in bed.

Fortunately, this clarity and insight does not translate into a speaker that forensically dissects music into an emotionless experience. Sure, they're superb at allowing you to hear instruments in the back of a mix that somehow normally get lost in the background noise – the sound gels into a very pleasing whole that lets you appreciate the finer mixes, without savaging some dodgier stuff. The separation between instruments is aided by their laser like image focus, resulting from a phase correct and constant crosser point and, in no small part, a very small cabinet. As mentioned, the cabinet isn't massively constructed but all of the panels are so small that it is impressively inert and the driver spacing is as close as you can get without becoming a coincident source driver. The net result is that performers stay locked in position, fore and aft, as well as across the soundstage and don't seem to defocus as the music gets louder and more complex.

The success in achieving such a large scale sound from diminutive boxes, is in no small part due to the Pro Sub which handles the bottom two octaves of output in a ,usually, seamless fashion. The Pro Subs upper bass output is very clean which aids the seamless transition to the Sats and generally it's a nimble, tuneful box well suited to delivering a high quality rendition of bass guitar and the like.

Acoustic Energy Pro Sub/Sat 5.1

Listening - Multichannel

Unsurprisingly, given that all five speakers are identical, tonal matching is absolutely spot on with the front soundstage as coherent as you will hear. Sounds and effects that pan across the front of the room do so smoothly and with absolute continuity, their positioning enjoying the same precision that was enjoyed by musicians in stereo. Again, as with the reproduction of music, vocal clarity is a strong point which is a big plus against the often more frenetic and less ordered backdrop of a movie soundtrack. In those more crowded moments, it's easier to pick out strands of individual sounds or voices in a crowd and it reduces the sheer wall of noise effect that overwhelmed speakers can deliver.

Movies aren't all crash-bang-wallop and indeed some movies lack room shaking effects altogether. I know, it surprised me too, but the happiness the Sats showed with low level music, manifested in resolving low level detail in subtle foley effects - the stuff that makes an atmosphere real. I don't know why it took me so long to get round to spinning up the Blu-ray of Duncan Jones' 'Moon', but the backdrop of serene tension is painted by the subtle hums and whirs of the moonbase machinery and very rarely does it take centre stage, which is left to the dialogue. The foley artists art is laid bare with small effects - way out stage left or right clearly portrayed and precisely pinpointed in space.

That said, as someone used to the diffuse reproduction of surround channels through di/tri-polar speakers, monopole rears are a very different experience. As a method of clearly hearing the information in the surround channels they're extremely effective but, perhaps as a limitation of my rectangular room, the continuity of sounds passing from the front to rear of the room did suffer from a slight gap in the middle. I ameliorated this to a large degree by pointing the speakers directly forward at the front wall to introduce a greater bias toward reflected, rather than direct radiated sound. I advise experimentation which would be true with most speakers in most non textbook Dolby/THX rooms which is, after all, most rooms. On the plus side, and as previously mentioned, its possible to provide a superb tonal match by using five identical speakers, so the flip side to the diffuse surround coin is that the surround effects are a better tonal match which makes the surround channels sound a bit less obvious than usual.

Of course no movie session would be complete without an explosion or two and I wasn't about to resist, so old favourites were dusted off in preparation for some good old alien/autobot/panda style fun and violence. And blimey, I'm still stunned by how hard such small speakers punch from the upper bass up through the midrange. It's clearly not as a result of limitless power reserves or huge drivers so the dynamic prowess can be blamed on the phase precision of the active crossovers and lack of smeering introduced by the passive alternative. In Kungfu Panda (Yes, again!) there is a short sequence where a long line of archers release arrows in quick succession progressing toward the screen. I've heard many (larger) speakers turn the wooden twangs into a more metallic snap as each arrow release gets closer and louder but the Pro Sats lapped it up without a hint of hardness and delivered a savage dynamic edge to the effect.

This resistance to coarseness makes for a very easy, unfatiguing listen, at high levels, as indeed does the natural, unforced tonal balance that still manages to deliver a delightfully shiny metallic tinkle to bullet casings dropping on a hard floor, without setting your teeth on edge when a glass bowl shatters, such as the notoriously borderline example in the magnificent House of Flying Daggers.

I generally found the slight softness, in the lower registers of the Pro Subs pass band, to be less noticeable with movies with a decent enough crunch factor in evidence. Clearly, the deepest effects aren't going to be on the cards and the Pro Sub made no attempt to torture itself trying which is the right compromise in my book. You have to pay a lot more and/or accept a much larger box to make these effects a tactile reality, so this should be considered a point of note rather than a case of damning with faint praise. It's a good little sub and a fine match in terms of the package.

Acoustic Energy Pro Sub/Sat 5.1

Verdict

7
AVForumsSCORE
OUT OF
10

The Good

  • Compact dimensions
  • Mounting flexibility
  • Room integration control
  • Refinement
  • Overall performance, regardless of size

The Bad

  • No grills on Sats
  • Setup a bit more involved than usual
  • No Auto ON/OFF
  • No colour options

Acoustic Energy Pro Sub/Sat 5.1

This is tricky. Based on pure performance terms, this is a superb package but it loses points in terms of domestic acceptability. A bit like being the best dancer on the show, but being marked down because you're a northern farmer - incredibly competent, but a bit annoying. The lack of grills, unlike the lack of an auto power off - which can be circumvented with remote control power switching for a small fee, is a domestic issue. I'm a tech head but I accept that having drivers permanently on display isn't something that my other half wants. If grills are present, I can always whip them off for critical listening but that option isn't offered with the Pro Sat/Sub and it will thus rule itself out of contention for many people.

Shame. Because for want of a ha'porth of tar this is a solution that offers a huge level of performance and I doff my hat to AE for offering the package up in spite of the potential issues. Many manufacturers wouldn't offer the chance to bestride the divide between consumer and pro, so the choice is yours and at least the choice is there.

I also worry that traditional hi-fi/AV dogma will prevent many people from considering such a package. There is this bizarre idea that certain amps suit certain speakers and that, for some reason, an amplifier and speaker designed in total isolation from each other can somehow result in a perfect match. With very careful consideration maybe they can come close, but what a package like the AE Sat/Sub package demonstrates is that, when the design of the drivers and amplifiers are considered part of a harmonious whole, the result of the sum of the parts can transcend the raw paper specs of either and by more than a small amount.

Integrating the power amplifiers with the speakers isn't blocking off an upgrade avenue - another aspect of active speaker design that seems to worry people. It is, in fact, removing a passive speaker crossover which is an impediment to amplifiers and drivers delivering their full potential. The other benefit of going active is that it more or less removes issues of power amplification matching and quality because, to a large degree, the latter is a function of the former and when you come to upgrade, it's an upgrade like any other, except you're not about to find that your new speakers are too much of a handful for your old amps.

So, with a few notes of the domestic variety, what we have is a discrete package of superb performance, within it's limits, and you can't really criticize a speaker that fits in the palm of your hand for not filling church halls. When you consider that each Pro Sat costs approximately £400 and includes two power amplifiers and an active crossover, it's clear we're dealing with a system that scores very highly on the value scale. Picture the entire system at a shade over £3000 with a £1000 processor and then for rooms of modest dimensions you will be getting a standard of reproduction that will take £4k worth of AV Receivers and passive speakers to the cleaners. Give it a try.

Best Buy

Scores

Sound Quality

.
.
.
7

Build Quality

.
.
.
7

Verdict

.
.
.
7

Value For Money

.
.
.
7
7
AVForumsSCORE
OUT OF
10

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