Hardware Reviews

Klipsch Forte IV


It’s funny how, after all my years in evaluating both hardware and software in the home music replay industry, there are still some venerable (not old but respected and well-established) names that have not passed through my listening room. In the speaker line I’ve had most types here, including stats, planars, horns, infinite baffles, plasma and so on. I had not expected what I heard in the latest, though.

Some have said that Klipsch is an acquired taste, or you have to know them to like them, or  – well, any one of a number of caveats. No different from aficionados of ribbons, horns or electrostatics then, really. So I treated them just like any other speaker – (except that this time I also get to play with a flea-powered single ended 2A3 triode amplifier as well as some bigger amps).

Treat them just like any other speaker? Hmmm. What a mistake. Few designs are crafted the way the Klipsch have been. Not passive ones anyway. Usually speakers have (relatively) slow roll-off crossovers, relatively low efficiency drivers, and sit in boxes with a reflex port. The Forte IV is the latest in a line of what might be termed heritage speakers, dating back to 1988. This particular beast sports a three/four driver array (depending on how you view passive radiators). On the front panel is an all-new compression driver, the K-702 filling in the midrange, with a tractrix horn which Klipsch claims ensures exceptional detail and dynamics. The tweeter is also a horn, with a titanium diaphragm and a new phase plug that claims to give a wider, more accurate sweet spot. A 12-inch high efficiency bass driver completes the front-firing driver line-up, and a 15-inch passive radiator is sited on the rear panel – which, if you’re not careful makes picking the things up a bit tricky, as it is almost as wide as the cabinet.


The crossovers have steep-slopes, and compared with many other designs around today, the overall system efficiency is high, well over the 95dB/watt mark. Loud music with ease beckons. Having heard Klipsch at shows in the past I thought I had a pretty good idea what to expect – with the caveat that most show sounds are rarely anything like home listening when you’ve had the time to get everything set up as you want. Also, you don’t usually visit shows late in the evening when the world is quiet, the mains is clean and you can really settle into some music.

One other observation, before I get to the what they sounded like bit. I had the Natural Cherry with Salt and Pepper grille finish and have to say, the veneer was stunning. Just a nice sheen, and verging on the cuddly side, a bit like speakers from yesteryear. Not all glossy and shouty but carefully understated, with the grilles being a gentler alert to their presence in the room than the flat black of so many others. 

The other thing which struck me was their weight. For the size of their cabinet they were not as heavy as expected. I’m not sure what I did expect, but having helped my son cart his KEFs up several flights of stairs – which was definitely a two-man job – I found these to be far more manageable. They’re not light, but not heavy for their size either. I used them in two situations. For serious listening they were firing down the length of my main music room, being some eight feet apart, and about three feet from the rear wall, slightly toed in. Then, because my wife liked the look of them (that’s a first) I plumbed them into the system in the lounge where they were basically flat against the wall, either side of the TV, but still some six feet apart.


I’ve always been a fan of the Borodin string quartets played by, appropriately enough, the Borodin String Quartet. I’m also fortunate to have some test pressings from EMI dating back to the mid 80s (before EMI classical went totally digital) so these LPs really are something else. The eventual production LPs were ASD4100. 

At first the bass seemed to lack a little weight and presence, especially the lower registers of the cello. Moving the speakers around a little didn’t seem to change things much, but aside from that the presentation was as close to being at a concert as I’ve heard for quite a while. Winding up the volume past where is was sensibly listenable didn’t produce anything untoward, and the speaker managed to retain its composure; no shrill treble, no midrange harshness, but also, the bass began to warm up a little. 

Which made me wonder if they need a little more running-in before listening. So I stepped back, and for the next couple of days various radio stations were played, along with Spotify, just to see what happened. Seven single malt whiskeys later. No, I’m kidding.


Settling down again a couple of days later there was a very real opening up and deepening of the bottom end. The cello in the same recording was now much more focussed, had a warmth and depth, and was hugely more articulate than the first listening. The viola had acquired a richness which wasn’t quite so apparent before, and the violin was certainly more finely etched in the upper regions. This is progress.

I threw a bit of London Grammar (Truth is a Beautiful Thing) into the system to see what would happen. To say I was surprised would be an understatement. Hannah Reid’s voice was piercing but clear, supported so very cleanly by that achingly deep bass. As before I tried moving the speakers around a bit to see whether placement was a significant factor in their performance, but around three feet out from the rear wall in my room was just fine. A foot forward or back from that seemed to make little difference. The really noticeable things, though, was that with a high efficiency design the really small dynamic contrasts become even more critical, and breathe a different sort of life into the music. London Grammar proved a point, and thinking back to the Borodin which had gone before, the dynamic contrasts were much more akin to real life than in many systems.

Another well-known album hit the system – Miles’ Kind of Blue. Sadly it’s become somewhat hackneyed over the past few years, with a plethora of reissues, squabbles over the proper speed of the original and so on. However, it contains some of the most insightful and ground-breaking jazz on the planet, and sometimes, just sometimes one needs to take a breath, step back, and hear it as new again. So, late one evening, in the quiet and the dark, Miles came to town and played Kind of Blue for me. What a revelation. 


Before plugging the speakers in I had wondered about the steep crossover slopes, and marrying not one but two horns with a conventional driver, and adding a passive radiator. I should have had more faith, because if ever there was an album to dispel doubts, this was it. The space around the performers was tangible. The spittle on the trumpet mouthpiece was as real as you could hope for. It was sooo easy to listen into the mix and hear what was going on – not just what was being played, but the ambience, the atmosphere, the sheer immediacy of the music. These speakers are transparent, rivalling the best electrostatics in that department. They have bottom-end clout which would suggest there’s a separate outboard sub (nope), and as I have already commented, they have dynamic contrast sewn up. The sudden first notes from Miles can literally make you jump. It’s like he’s right there, playing to you. 

But there’s bass, and then there’s that almost subterranean low frequency stuff you get in large spaces, like cathedrals. Wonder how that comes across. A quick shufty through my recordings, and Elgar, recorded in Worcester Cathedral was put through its paces. 

This time the enormity of the cavernous space was clear for all to hear; such a contrast from the earlier more intimate environment of Kind of Blue. The choir was at a distance, with just the right amount of detail coming through, as if I was sitting somewhere back in the nave. The organ was really nicely balanced, and there was clear definition between the low organ pedal notes and the aural clues to the size of the space it was in – something that’s so difficult to achieve as any blurring of phase at the bottom end can completely muddy the aural picture.


Once again the dynamic contrasts were something which really put a smile on my face – somehow the music became effortless to listen to – a bit like it does live. It’s rare that you go somewhere to listen to acoustic music and want to turn it down. So for serious listening, these speakers, at this price, are something which are going to be very hard to beat. Admittedly they won’t fit on a bookshelf, though many (if they heard them) might wish they would. But they are a complete speaker. They are transparent. They go deep. They have an uncanny ability to make music sound real, and, just as real live music would, to make you jump (in a good way). They go low enough to satisfy 95% of the infra-bass freaks, and certainly low enough for lovers of organ music and genres akin to the London Grammar. And yet they can convey the utter beauty and charm of the most intimate classical music.

Ah but what of female vocals, an area so beloved of many audio lovers. Well, Janet Baker singing Elgar’s Sea Pictures(Sacred Music CSD3660) was simply sublime. Karla Bonoff has a tangible grit and sway to her voice which is unmistakeable. Joan Baez and her earthy pleadings similarly unique. Yes, they do female vocals too.

Another question on some peoples lips: OK, so they’re high efficiency. What amp will drive them? Well, I tried a humble (but nicely restored) pair of Heathkit MA-12 monoblocs. EL84s pentode valves in essentially the Mullard 5-10 circuit, but with Leak tendencies as well, squeezing out around 12 watts. Sublime. The Klipschs were easy to drive, dynamics seemed no less dynamic, and the listening was easy. The Heathkits weren’t quite as quiet as some amps – that’s one disadvantage of a high-efficiency speaker, any system noise will be that much more apparent, but they weren’t noisy enough for it to be a problem when listening until you really cranked things up, and then it was more likely to be noise at source in reality, than the amps themselves.


So down to 2.5 watts of a single 2A3 triode valve per channel. Well, I love the 2A3, so I suppose there’s a degree of bias there, however, these speakers are so sensitive that in terms of loudness and dynamic control there was little to choose between the MA-12s and the 2A3. Ultimate loudness was necessarily lower – the humble 2A3 can only do so much – but in other respects it packs more than enough punch with these speakers than would be needed in all but the largest of rooms. 

As for solid state – I felt (dangerous territory) that there was a slight shift in the sound quality. No better, no worse, just different, but again no less enjoyable. Dynamic contrasts were well handled, and ultimately the sound quality was far more dependent upon the amplification than the speaker. Give the Fortes a good clean signal and they would reproduce it as faithfully as possible. So I suppose the caveats are that power is not an issue, but a good quality system is important as the Fortes will reveal (not ruthlessly, but will reveal) any weakness along the way.

My advice – go and listen to a pair. Even if you can’t afford them, go and listen. They are incredibly good. They are even domestically acceptable, we put them into the sitting room, as part of the TV system, so they had all sorts of things thrown at them including the odd soap, a film or three, thrillers and Paw Patrol (blame the grand-daughter for that). 

They made dialogue much easier to understand and with films, especially something like Dunkirk with lots of bang and slam, or thrillers with a lot of low frequency content they were absolutely superb. Not sure I can run to affording two pairs (probably not one either), but if I could I would. They really do perform well, and are probably the nearest thing to a complete speaker I’ve had at home.


Type: horn loaded 3-way floorstanding loudspeaker
Crossover frequency: 650Hz, 5.2kHz
Drive units:
Bass: 304.8mm fibre-composite cone woofer, 381mm passive cone radiator 
Midrange: horn loaded 44.5mm polyimide compression driver 
Tweeter: horn loaded 25.4mm titanium diaphragm compression driver 
Nominal frequency response: +/ -3dB 38 – 20,000 Hz
Nominal impedance: 8 Ohms
Connectors: bi-wire binding posts
Sensitivity: 99dB @ 2.83v/1m
Dimensions HxWxD: 908 x 422 x 330mm
Weight: 32.7kg
Finishes: American walnut/salt & pepper grille, Natural cherry/salt & pepper grille, Black ash /salt & pepper grille, Distressed oak/lambswool grille
Warranty: 2 years

Price when tested:
Manufacturer Details:



floorstanding loudspeakers


Chris Beeching

Distributor Details:

Henley Audio Ltd
T +44(0)1235 511 166

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