Klipsch Heresy IV without the front grille showing the Tractrix horns

The Klipsch’s Heresy IV floortstanding loudspeaker hails from an original 1957 design made by company founder Paul W. Klipsch. Still going strong and retaining its heritage from Hope, Arkansas, the original Heresy got its name because Klipsch demanded a compact centre speaker be built to accompany a pair of Klipschorn floorstanders in a three-speaker stereo array. This was deemed to be a design ‘heresy’ for the brand and the name stuck.

Design

The Klipsch Heresy IV is a three-way configuration. A K-107-TI titanium diaphragm handles higher frequencies and is fitted with a phase plug to increase the sound dispersion. The 4.45cm K-702 midrange compression driver, featuring a polyimide diaphragm is ‘mated’ to a Tractrix horn designed to throw the sound far and wide. The thinking behind this Tractrix geometry is to reduce air turbulence as it enters the port, delivering sound more efficiently. Completing this driver array, an imposingly large 30.5cm K-28-E fibre-composite cone woofer handles the low frequencies. For the first time in the Heresy range, this updated version features a rear-firing bass port utilising the same Tractrix geometry. This new design arrangement claims to extend the low-end frequency range down to 48Hz – making the full frequency range a claimed 48Hz to 20kHz.

The rear port extends the low-end frequency response

Quality

These speakers are substantial and weigh in at a hefty 20.4kg each. The MDF cabinet feels a bit thinner than I expected, it is soft to the touch and seems to mark quite easily and I am a bit concerned about long-term wear. Available finishes include satin black ash, natural cherry, distressed oak, or American walnut wood. All finishes are priced at £3,500.

I was delighted with the way they look in my listening room and quickly posted a pic on our Insta channel of the pair newly installed. To my surprise, one follower commented saying ‘Oh, have you got your grandad’s old speakers?’, which I felt was a bit unfair considering the model’s classic old-school charm.

Measuring 64 x 40 x 34cm (HxWxD), the Heresys are around half the height I would usually expect for a floorstander and a good bit wider. Each cabinet comes fitted with its own slanted, riser base and you can easily move them out into the room for optimum positioning for critical listening, say, and then shove them back against the wall for a less obtrusive feel when the family arrives in the room.

The Klipsch Heresy IV riser base has an upward angle of 10 degrees to the horizontal, projecting the tweeter towards the listener

The riser base support angles the drivers upwards by about 10 degrees to point towards the listener’s ear level when seated. There are no spikes to isolate the cabinet from the floor and the underside of riser base support is smooth, making it easy to slide the cabinets into position on a carpeted floor.

Performance

Setting up

I set up the Klipsch Heresy IV in my lounge, which is 10 by 6 meters in size, and drive them via a Naim NAP 250 power amplifier fed by a NAC-N 272 preamplifier using a Naim XPS power supply. This combination of Naim electronics is one I know well and can deliver a wonderfully deep tone with plenty of energy and bounce as the music demands.

Forward

With the Naim electronics in the driving seat, the Heresy speakers sound ‘lively’ and ‘forward’. Rated at 2x 80W, there is plenty of power from the NAP 250 but the Klipsch speakers are particularly easy to drive due to their horned design and claimed sensitivity of 99dB. I am getting a big sound for the room but this is not a problem as I am compromising by not needing much volume and I can get a quality sound that I can comfortably listen to.

Listening to the speakers for the first time with familiar but heavily layered music tracks such as Pyramid Song and Pulk/Pull Revolving Doors from Radiohead’s Amnesiac album, the Heresys are less enjoyable and too crisp for my tastes. I get a similar reaction with some bigger orchestral classical pieces such as Rachmaninov’s 2nd Piano concerto – Decca CD, Concertgebouw Orchestra with Vladimir Askenazy – although I have to say, quieter pieces like Yo-Yo Ma’s Inspired by Bach The Cello Suites (Qobuz 16-bit/44.1kHz) and Daniel Barenboim’s Chopin Nocturnes – Deutsche Grammophon CD – are delivered beautifully and with clarity.

Where these speakers really get into their stride though is with guitar-led music, and Bruce Springsteen’s track The River takes me there every time. With the Heresy’s public address-style, horn-loaded configuration, this track reminds me of going to see Springsteen perform at Earls Court almost 25 years ago. The Weeknd’s Blinding Lights delivers another really enjoyable moment and the Heresys clearly excel with simple yet detailed recordings.

Resolution

In terms of their detail and delivery, the Heresy speakers are very impressive. Streaming Ezra Collective’s What Am I to Do? via Qobuz in 16-bit/44.1kHz, the detail in Loyle Carner’s humorous vocal is beautiful, as are the metallic cymbals near the end of the track. The high-hat towards the back of the soundstage is clear as are the many background interjections from the Collective throughout the track.

With T+A electronics

With the Klipsch Heresy IV speakers moved from the lounge into my larger listening space and driven by my resident T+A PA 2000 R integrated amplifier, the speakers show a little more refinement as the sound fills out the space and is able to breathe, making everything sound better.

In this space, live music recordings feel more dynamic and rhythmic, particularly with albums like Sam Cooke’s Live at the Harlem Club, 1963. The recording is known for its ‘raw’ sound with high levels of audience noise and chatter. The energy from the audience is palpable as it is projected through the speakers into my listening room, transporting me into their space and experience which feels fantastically realistic.

Similarly, Nils Loghren with his Acoustic Live album is another example of a vibrant live gig recording. Listening to Keith Don’t Go, the harmonics in the acoustic guitar and the almost incidental tap on the body of the guitar comes across really well. This is a live performance to listen to and enjoy, not just because of the excellent songwriting but also because of the recording itself – it is crystal clear with a spectacular insight into musicianship and engineering and shows just how good live recordings can sound.

The Synthesis Soprano integrated amplifier has a built in DAC

With tube amplification

It is something of a Klipsch heritage throwback perhaps, but many of the images on the company’s site often show the Heresy IV partnered with a valve amp. I have heard a lot about the brand’s valve amp partnerships and was keen to try one out with the Heresy and managed to secure the new Synthesis Soprano LE integrated valve amplifier. Priced at £1,349, the Soprano is rated at just 12W per channel, but despite the lower power output compared to the Naim and T+A solid-state amplifiers, the Heresys bounce along with the same amount of energy, dynamic response and fast rich bass.

Overall

There is no denying the energy and dynamism the Klipsch’s Heresy IV speakers are able to generate but as with all speaker designs, partnering equipment should be carefully considered. I achieved my best listening experience with the Heresys driven by a modestly-powered tube amplifier, and the pairing resulted in a clean delivery and a fraction less edge.

If you love listening to live recordings or rock‘n’roll, you really must hear your favourite tracks through these terrific speakers. They’re sound is more Springsteen than Radiohead, but in the right space and driven by a carefully chosen amplifier, they deliver the kind of engagement that makes you reconnect with your music, which after all is what it’s all about.

The Klipsch Heresy IV are available through Henley Audio at £3,500 a pair.  Henley also retail the Synthesis range of tube amplifiers, the 12W Soprano will be available in the summer (2021).