JBL S4700 Floorstanding Loudspeaker Review
AUD $27,000 RRP
Since its birth in 1946, JBL has been a significant player in the loudspeaker world, making notable contributions to studio monitoring and sound reinforcement for cinemas, concert halls, rock concerts and music festivals. It has also made quite a reputation for itself in domestic hi-fi equipment, especially in its native USA. To any audiophile reading this review, this great marque needs no introduction.
JBL's Synthesis S4700 is one of seven floorstanders in the high-end JBL range, and at AUD$27,000 is just about affordable to well-healed hi-fi junkies. Measuring 1060x500x370mm, it is physically quite large – meaning that you'll need a suitably big residence to house this loudspeaker – and at 55kg it's heavy enough for you to require a private osteopath should you ever decide to move it. Think of this speaker as being like a small fridge in size and a compact home safe in weight. For this reason, unboxing a pair of these is not a task for the timid – so you'll undoubtedly require assistance of the human variety, if not the medical!
True to JBL tradition, your money buys you a large three-way loudspeaker that's quite different to most of its price rivals. It houses a hefty 380mm bass unit, a 45mm high-frequency compression driver and a smaller 19mm ultra-high frequency compression driver, in a horn arrangement. The bass unit comes in below 800Hz and uses a strong cast aluminium frame with heavy-duty dual 75mm voice coils and a neodymium magnet; its cone is made from pure pulp. Both higher frequency compression drivers use titanium diaphragms, with the larger driver also being Aqua-Plas coated to improve damping. These are located within a single dual horn assembly with custom horn shapes for each of the drivers. The larger midrange driver works between 800Hz and 12kHz, after which the tweeter takes over. The cabinet is bass reflex loaded, with a rear-facing tuned port.
Claimed frequency response is 38Hz to 40kHz (-6dB) which is a very wide range indeed. The power handling is said to be 300W RMS, so it can be paired with some very powerful amplifiers, yet the quoted 94dB (2.83V@1m) sensitivity means it can also play loud with some pretty low powered ones too. The quoted 6-ohm nominal impedance is fairly standard, so this will be an easy load for practically any amplifier out there, and particularly friendly to valve amps thanks to its gloriously high sensitivity.
Its loudspeaker binding posts are doubled up for bi-wire or bi-amplified connectivity. I tried a few pairs of single wired cables to both mono and stereo power amplifiers, both tubed and solid-state, with a good deal of success and little fuss. The S4700 comes fitted with thin brass connection strips between the binding posts and although these worked well enough, inserting short Cardas Audio bi-wire jumpers made a noticeable improvement to the sound.
With a very large, wide dispersion pattern of radiating sound thanks to those high-frequency horns, the S4700 is reasonably easy to position within the listening room – with some caveats. It prefers a larger room to a smaller one and should be positioned a least a couple of metres away from your seating position. A pair of these loudspeakers really drives a spacious room well, but can quickly overpower medium-sized ones if they're positioned too close to the rear boundary wall - I'd suggest at least a metre away from any wall. With its rear-firing port, the amount of bass reinforcement put back into the room is proportional to the distance to the room boundaries.
During the review period, I used the S4700 in two different large listening rooms, one 5x9m and the other 6x8m. They're an imposing speaker with a presence that's hard to ignore. Most of my listening was done using Cary Audio electronics; the excellent DMS-600 network streamer as a source, connected to the two-box Cary SLP-05 Class A triode preamplifier and CAD-805 single-ended Class A tubed monoblocks. Using the high-end, heavy-hitting set of electronics suited the JBLs very well. I also used a Mark Levinson ML5802 solid-state integrated but preferred the Cary Audio tube gear.
It didn't come as a complete surprise to discover that the JBL S4700 sounds vast. It has so much of everything – scale, drama, dynamics, bass slam and detail, plus a sense of complete unflappability and grip. Indeed listening to Claude VonStroke's Who's Afraid of Detroit? with a generous amount of volume was almost an out-of-body experience. The S4700 has the ability to provide ground-shaking bass with no apparent limit to how hard it can punch or how loud it can play. My ears gave up before the loudspeakers did, which is a rarity. Even when thumping away at full tilt – with the sweet sensation of air hitting my chest as if I was stood in front of a PA stack at a rock concert – the midband and treble clarity remained surprisingly composed. These horned compression drivers do a marvellous job of keeping up with the speed and ferocity of the bass drivers, delivering copious quantities of easily discernible detail.
Another track that came alive was seeya by Deadmau5. The bass guitar sounded palpable when listening through those huge JBL bass drivers, which provided a solid foundation to the song. The kick drum was clearly separate in the mix from the bass guitar and had such speed and solidarity that it was amazing to hear. Conversely, it wasn't all about tight extended bass, because the rest of the track proved equally special. Colleen D'agostino is the female vocalist on this song, with a voice that suits it nicely. She soared delicately above that earthquake of a bass line, maintaining a great sense of poise as the JBL held nothing back.
Give this loudspeaker a clean signal through a neutral amplifier, and it delivers pure music right back at you. I swapped out a single cable and immediately heard the difference very clearly. The Synthesis S4700 demands to be at the end of a high-quality system and should be paired with the best electronics available. This done it will tell you what's on the recording, and what's not. For example, Yello's The Expert had far less bass compared to the Deadmau5 track, showing that this speaker only reproduces what it's told to.
This isn't just any old big banger, though. It can be subtle and smooth too when called upon so to do. I cued up nineteen sixties folk ensemble Peter Paul and Mary singing Don't Think Twice, It's Alright – a live recording in Japan from way back in 1967. Their voices extended well beyond the speakers, but not in an overblown way – I heard a realistic image of the three performers on a live stage. The guitar work was detailed and delicate, and a believable part of the performance. Indeed this was one of the finest renditions of this track that I've heard, with all of the scale and accuracy that make a performance sound utterly realistic.
With Aventime by Agnes Obel, the cello and plucked strings sounded suitably real with depth, definition and detail; the song came over as smooth yet true to the timbre and tone of the instruments. Those horns do a fantastic job of dispersing the soundstage throughout the listening room, much like an actual live performance. The result is that these loudspeakers can make a straightforward track sound grander, larger and more lifelike than you might think, while continuing to be just plain good old fashioned fun. With Sophie Ellis Bexter's Heartbreak (Make me a Dancer), I couldn't stop my feet tapping. I duly consider it to be one of the most enjoyable loudspeakers I've heard for a long time.
To my ears, the JBL S4700 is one of the world's greatest loudspeakers – at this price point, or anywhere near it. If you have a large enough room to fit a pair of them in, along with suitably high-quality amplification, preferably using single-ended valves with good cables, then you're in for a musical treat, as they make everything energised and alive. Better still, you don't have to turn up the volume, as this speaker has a wonderfully easy and unstressed feel at low levels, so it's not just for headbangers. If there's such a thing as a hi-fi fun factor, then this one goes up to eleven.
For more information, visit JBL.
Starting his first audio consultancy business in the early ’80s whilst also working professionally in the electronics industry, Mark now splits his time between professional reviewing and AV consultancy.