This week we reviewed the Klipsch Heresy IV loudspeaker, the fourth generation of the iconic three-way speaker created over 60 years ago. This last version brings its fair share of innovations, among which are new speaker drivers, a modified crossover filter and a bass-reflex enclosure. This is the first time a Klipsch Heresy loudspeaker has implemented this type of enclosure. Sold for €3,790 a pair, will the Klipsch Heresy IV manage to outperform the previous versions?
Klipsch Heresy IV: the brand
The Klipsch saga began in the late 30s when Paul Wilbur Klipsch began developing his first speakers inside a small hangar in Hope, Arkansas. Met with great enthusiasm from his audiophile friends, Paul Wilbur Klipsch decided to found his company and commercialize his first loudspeaker, the Klipschorn, in 1946. This patented model was developed for a very specific purpose: to reproduce the emotion of a live concert at home. This feat was achieved thanks to the integration of a 15” low frequency driver, a 2” midrange driver with a compression chamber, and a 1” tweeter with a compression chamber and Tractrix horn. This model was so successful that more than 70 years after its release, the sixth generation of this speaker is still in the brand’s catalog under the reference Klipsch Klipschorn AK6.
In 1957, Klipsch introduced the first version of the Klipsch Heresy loudspeaker, a 3-way model made to accompany a pair of Klipschorns and deliver the center channel in high fidelity. This novel idea didn’t find an audience and was quickly abandoned in favor of a classic stereo configuration. The speaker then became an instant success and went through multiple revamps, the latest of which is the Klipsch Heresy IV, which we are reviewing today.
Today, Klipsch is also a major player in the movie theater speaker market. It all began in 1980 when the brand designed a digital sound system for John Allen. In this system, each channel was reproduced by a Klipsch MCM loudspeaker, an exceptional model equipped with a 15” subwoofer, a 12” Tractrix horn-loaded midbass driver and a titanium Tractrix horn-loaded tweeter.
After gaining a solid reputation for professional movie theater audio systems, Klipsch set out to conquer the home theater market in 1992 with the release of its first in-wall speakers, the Klipsch IW 100 and IW 200, followed by the first Klipsch Rebel 8 surround speakers in 1996.
The early 2000s were a pivotal moment for Klipsch. The American brand continued to produce its iconic hi-fi and home theater speakers, but expanded its product range to cater to new ways of listening to music. As a result, the brand now has an extensive catalog featuring hi-fi headphones, Bluetooth headphones, true wireless in-ear monitors, smart speakers, wireless speakers, and soundbars.
Klipsch Heresy IV: packaging & accessories
The Klipsch Heresy IV come in two large cardboard boxes in which the speakers are held in place by two polystyrene blocks. Each speaker is protected by a synthetic cloth and comes with a magnetic acoustic grill. Also included is a user guide which explains how to get the speakers out of their box. First, open the top of the cardboard box. Each speaker is placed upside down, so you simply have to turn the box over to easily pull it off.
Klipsch Heresy IV: presentation
Design
The Klipsch Heresy IV retains the extremely appealing vintage design of its predecessors. It is fitted with a removable slanted riser base which allows you to place it on a stand or directly on the floor. The only minor difference is that the front part of the base is straight, whereas the base of the Heresy III was slightly curved.
Like all the other speakers in the Heritage Range, the Klipsch Heresy IV compact speaker is entirely handmade in the Klipsch workshop located in the United States. The cabinet is made of 2cm-thick plywood covered with a damping resin with a granular finish on the front and back panels. The rest of the cabinet is covered with a natural wood veneer. The wood veneer used for each pair of Klipsch Heresy IV is systematically cut from the same tree trunk. The cabinets are thoroughly examined so that the two loudspeakers which make up a pair are almost indiscernible. The two speakers that make up a pair follow the exact same path in the factory and are labeled with sequential serial numbers.
The speaker drivers of the Klipsch Heresy IV are concealed behind a wide acoustic grill made of polymer fibres and emblazoned with the Heresy logo. This grill features a magnetic fixation system, which makes it very easy to take off if you want the speaker drivers to be visible.
Speaker drivers
The Klipsch Heresy IV is a three-way model fitted with three speaker drivers, two of which are horn-loaded.
Low frequencies up to 850Hz are handled by a large 12” (30cm) fiber composite cone woofer that has a surround with small folds and light moving parts.
This woofer is loaded in a bass-reflex enclosure, which is a first for a Klipsch Heresy loudspeaker. The port is located under the loudspeaker terminals and allows an extended response in the lows. The frequency response of the Klipsch Heresy IV in the lower end of the sound spectrum goes down to 48Hz, while the previous model reaches 58Hz. Moreover, this port features the iconic Tractrix technology used to optimize the airflow while reducing the noise it generates. On paper, this design promises deeper lows. However, it is essential to leave some space between the speakers and the rear wall in order to preserve the overall sound quality.
The frequencies between 850Hz and 4500Hz are handled by a new K-702 midrange driver. This model was already used for the very high end Klipsch Cornwall IV. This compression driver features a 1.75” (44.5mm) polyimide diaphragm and is horn loaded in order to extend the listening area. The manufacturer announces extremely detailed mids with an exceptional dynamic range.
Past 4,500Hz, a 1” (25mm) K-107-TI Titanium diaphragm compression driver takes over up to 20kHz. It features a brand new wide dispersion phase plug. The tweeter is loaded in a compression chamber and a Tractrix horn. The listener can therefore enjoy a more accurate and wider listening area.
Acoustic horns
Using horn-loaded drivers is no novelty for Klipsch. It actually has been the brand’s trademark for over 70 years. The American manufacturer has perfected the mastery of acoustic horns to mechanically amplify the sound of loudspeakers and naturally increase their sensitivity. Each horn-loaded driver enjoys a significant increase in sensitivity and gains a few precious decibels. The Klipsch Heresy 4 has a sensitivity rating of 99dB at 1m for 1 watt. However, despite this high sensitivity rating, it is recommended to use a relatively powerful amplifier (100 watts minimum) to drive these speakers efficiently.
New crossover filter
The crossover filter used for the Klipsch Heresy IV compact speaker has been entirely revamped. It is based on the steep slope, 3-way filters used for the iconic Klipsch Klipschorn, Klipsch La Scala and Klipsch Cornwall. It features high-end components and its design has been optimized to keep signal deterioration to an absolute minimum throughout its path. This results in a more precise and realistic sound, increased sensitivity, and optimized power handling.
Dual binding posts
The Klipsch Heresy IV speaker is equipped with dual binding posts, which makes bi-wiring and bi-amping possible. These binding posts are mounted on a solid aluminum plaque decorated with the Klipsch and Heresy logos. Audioquest Star Quad Type 4 speaker wire is used for the internal wiring that connects the binding posts to the crossover filter and the crossover filter to the drivers. This high-end model features solid conductors in long grain copper (LGC) to preserve and transfer the entire audio signal, without coloring or altering it.
Key specifications
- Speaker type: 3-way bass-reflex enclosure
- Cabinet: medium density fiber
Speaker drivers
- Lows: 12” (305 mm) K-28-E with composite fibre cone
- Mids: K-702 compression chamber driver with a 1.75” (44.5mm) polyimide cone, loaded in a K-704 Tractrix Horn
- Highs: 1” (25mm) K-107-TI titanium tweeter loaded in a Tractrix horn
Measures
- Nominal impedance: 8 ohms
- Cutoff frequency: HF: 4500Hz – LF: 850Hz
- Power handling: 100W RMS (400W peak)
- Frequency response: 48Hz – 20kHz (± 3dB)
- Sensitivity: 99dB /1W/1m
- Max SPL: 116dB
General
- Dimensions with stand (WxHxD) : 39.4x63x33.7cm
- Weight: 20.4kg
Klipsch Heresy IV: testing conditions
For this review of the Klipsch Heresy IV loudspeakers, we first connected them to a Rega Aethos amplifier using Viard Audio Silver HD12 HP speaker wire. This amplifier is a solid-state model capable of delivering up to 2x125W at 8 ohms over a wide bandwidth. We then connected the speakers to a McIntosh MA252 amplifier, which has a power rating of 2×100 watts at 8 ohms, using QED XT40i speaker wires. We listen to music using a Pioneer UDP-LX500 Blu-ray player, a Rega Planar 3 turntable connected to a Thorens MM08 using Viard Audio Premium HD cables, and 24-bit/96kHz compatible network player to stream music from Spotify and Qobuz.
Klipsch Heresy IV: listening impressions
We started listening to the Klipsch Heresy IV speaker by playing Eric Clapton’s Unplugged album. With this acoustic live session, the Klipsch Heresy IV delivered an incredibly rich sound. We were able to hear a plethora of details that we hadn’t before noticed with this album, even though we had listened to it many times. The various notes played on the acoustic guitar were delivered in a very natural manner and with great clarity. Even the most subtle nuances are perceptible. The sound stage was spacious and all the different instruments were accurately reproduced. The British singer’s vocals sat right in the middle of the sound stage and remained extremely natural at all times. Even when we turned the volume up excessively high, the Klipsch Heresy IV maintained perfect control of the different frequency ranges.
We then listened to Nothing Else Matters by Metallica to test the speakers with a different musical genre. The highest notes of the guitar solo felt a bit projected. However, the listening experience with the Klipsch Heresy IV remained lively and dynamic. Percussions were extremely clear, the lows were tight and perfectly under control. This feat is possible thanks to the 12” driver’s rigid cone. However, this characteristic also prevents the Klipsch Heresy IV from reproducing very low frequencies (below 48Hz), but each impact was perfectly heard and felt.
Klipsch Heresy IV: compared to…
Klipsch Heresy III: the sound signature of the Heresy III is quite similar to that of the Klipsch Heresy IV. The new bass-reflex enclosure brings more character to the lows, without affecting the responsiveness of the speaker in this frequency range. The rigid cone ensures tight and dynamic lows which always remain perfectly under control.
Magnat Transpuls 1500: sold for €1,090, this loudspeaker made by Magnat is a three-way model loaded with a 15” woofer, a 7” midbass driver and two horn-loaded tweeters. When it comes to the listening experience, the Magnat speaker offers more powerful and deep lows. This frequency range is less responsive and not as tight as it is with the Klipsch speakers. The Magnat’s ability to accurately reproduce the sound of instruments is also inferior to that of the Klipsch speakers.
Klipsch Forte III: the Klipsch Forte III are the big siblings of the Klipsch Heresy IV. They are bigger and therefore have the capacity to deliver more powerful lows thanks to a 12” driver coupled with a 15” passive radiator. Their frequency response in the lows goes down to 38Hz, while the Heresy IVs are limited to 48Hz. The mids and highs are also extremely accurate, which results in an even higher level of detail than with the Heresy IV. However, a fairly large room is necessary for these speakers to reach their full potential.
Klipsch Heresy IV: conclusion
The Klipsch Heresy IV lives up to the previous models from the Heresy range. It retains the design and sound signature of the iconic series while bringing extra clarity and in the mids and a better response in the lows thanks to its bass-reflex enclosure. The lows are deeper, more powerful but remain under control. The Klipsch Heresy IV loudspeaker particularly shines with acoustic recordings and is able to reproduce extremely subtle nuances in voices and instruments. Play a live recording and simply close your eyes to feel like you are there. However, despite a high sensitivity rating of 99dB, the Klipsch Heresy IV should be paired with a powerful and dynamic amplifier to develop the entirety of its potential.
What we liked
- The vintage look
- The clarity and the accuracy of the sound
- The control of the lows
We would have liked
- Smoother highs (although this may be a matter of preference)
Thank you for sharing your info.
If the speaker has a 99 dB sensitivity (it does), AND can handle 100 watts (it can: 100 – 400 watts for this speaker), then, it should have a maximum SPL of AT LEAST 119 dB (at 100 watts), and 125-ish dB peak SLP (at 400 watts). To account for the missing 3+ dB error, are there maximum-excursion or some other issues of which we are not being informed?