Klipsch Heritage: Range Overview

Very few loudspeaker lines have survived unbroken since the 1940s, and fewer still are made in the same town by the same company. The Klipsch Heritage range began in 1946 when Paul W. Klipsch started building the Klipschorn in Hope, Arkansas, and the current models are still assembled there, built to order, with book-matched veneers and sequential serial numbers so that a pair leaves the factory as a matched set.

What makes the range worth understanding as a whole is that it is not a conventional ladder of small-to-large boxes. Every model is horn loaded to some degree, and the real distinction is how much of the frequency range gets a horn. That single decision drives sensitivity, cabinet size, placement requirements and, in the end, what kind of amplifier you should be shopping for. This article works through the seven current models, from the compact Rebellion bookshelf to the Jubilee, and explains what actually changes as you move up.

Sensitivity first: why these speakers are different

Before comparing models, it is worth being clear about why horn loading matters, because it determines system matching more than it determines taste.

A horn is an acoustic transformer. It couples a small, light diaphragm to a large volume of air, which means the driver converts far more of the electrical input into sound and far less into heat and cone excursion. The practical consequences run through everything else:

• Sensitivity. The Heritage models range from 99dB to 105dB at 2.83V/1m, with the Jubilee’s drivers quoted higher still. For context, a typical modern floorstander sits around 87dB to 89dB. A 99dB speaker needs roughly a tenth of the power for the same output.
• Amplifier choice. At these sensitivities, a well-made low-watt single-ended triode amplifier is a serious proposition rather than an eccentric one. Low-power valve designs work here because they are never asked to leave their comfortable operating range.
• Distortion at real listening levels. Because the drivers barely move, they stay in the linear part of their travel. Dynamic peaks arrive without the compression you hear from a small cone working hard.
• What you hear. Attack transients keep their leading edge, a snare crack sounds like a snare crack, and there is a sense of unforced scale at low volume that conventional designs struggle to match.

The trade-off is honesty about the rest of the system. A high-sensitivity speaker amplifies amplifier hiss, mains hum and a noisy phono stage just as efficiently as it amplifies music. These are not speakers to pair with a compromised source.

Where the range starts

Klipsch Rebellion

The Klipsch Rebellion is the newest model in the range and the only standmount, drawn from Paul Klipsch’s 1958 Model H concept, a design that never reached volume production at the time.

It is a two-way, which makes it structurally different from everything above it. A K-81-EP 8-inch woofer works into a bass reflex cabinet with a rear Tractrix flare port, and above 715Hz everything is handled by the K-702 compression driver on a K-703 Tractrix horn with Mumps contouring. That driver is worth noting: it is the same unit used as the dedicated midrange in the Heresy IV, Forte IV and Cornwall IV, here asked to cover the treble as well. The consequence is a single source from the upper bass to the top of the audible band, with no crossover anywhere near the region the ear is most sensitive to, which is the same argument the Jubilee makes at the other end of the range.

Sensitivity is 95dB, the lowest here but still six to eight decibels above a conventional standmount. Quoted response is 60Hz to 20kHz at plus or minus 3dB, reaching 45Hz at the minus 10dB point, and maximum continuous output is calculated at 115dB. The cabinet is 485mm tall in 18mm MDF with real wood veneer, at 14.5kg per speaker, and magnetic cloth grilles are supplied.

One specification deserves attention before you plan a system around it. Impedance is 8 ohms nominal but drops to 3.3 ohms at 170Hz, which is a genuine load in the upper bass. Unlike the rest of the range, this is not an obvious partner for a low-power single-ended valve amplifier. A well-made transistor integrated, or a push-pull valve design with a 4 ohm tap, will give you the grip in the bass that the driver is capable of.

Buy Klipsch Rebellion at Premium Sound – £2,699

The compact three-way models

The next three models share an architecture: a direct-radiating woofer in a conventional cabinet, with horn-loaded midrange and treble above it. They give you most of the Heritage character without the footprint of a full bass horn.

Klipsch Heresy IV

The Klipsch Heresy IV traces back to 1957, when Paul Klipsch proposed a compact speaker to sit between two Klipschorns as a centre channel. The name came from a colleague’s reaction to the idea.

At 630mm tall on its removable slant riser, it is the smallest speaker here by a wide margin, and the easiest to accommodate. The current version pairs a K-28-E 12-inch fibre-composite woofer with a K-702 1.75-inch polyimide compression midrange on a K-704 Tractrix horn, and a K-107-TI 1-inch titanium compression tweeter. Sensitivity is 99dB, impedance 8 ohms, and the crossover points sit at 850Hz and 4500Hz.

The significant change in the IV is the rear Tractrix port, the first port in the model’s history, which extends the bottom end by close to 10Hz and takes the quoted response down to 48Hz. That is still the shallowest bass extension in the range, and in a large room the Heresy IV will want a subwoofer if you listen to organ music or electronica. In a normal British living room, and particularly on a stand or riser that puts the horns near ear height, it plays with a directness and a rhythmic grip that its size does not suggest. It is also the most placement-tolerant model here, happy roughly a foot from the wall behind it.

Buy Klipsch Heresy IV at Premium Sound – £4,699

Klipsch Forte IV

The Klipsch Forte IV solves the Heresy’s bass limitation without going to a much larger cabinet. It uses a K-281 12-inch woofer on the front baffle and a KD-15 15-inch passive radiator on the back, a combination that trades a little immediacy for a lot of extension. Quoted response is 38Hz to 20kHz at plus or minus 3dB, the tightest tolerance figure in the range.

A passive radiator behaves like a port with a mass instead of a column of air. It has no port noise and no chuffing at high levels, and it lets the designer tune the bass alignment lower than the cabinet volume would otherwise allow. The 15-inch radiator here is larger than the driver powering it, which is what buys the extension.

The midrange is the same K-702 compression driver as the Heresy, here on a K-703-M horn, with a K-100-TI titanium tweeter on a K-79T horn above it. Crossover points move to 650Hz and 5.2kHz. Sensitivity stays at 99dB and the cabinet is 908mm tall with a 422mm width, so the footprint is modest for what it does.

The Forte IV has a reputation as the balance point of the range, and the reasoning holds up: full-range bass, a slim footprint, and tolerance of positions closer to walls than the Cornwall will accept. The rear radiator does mean it needs some breathing room behind it, so treat 200mm to 300mm as a starting point and adjust by ear.

Buy Klipsch Forte IV at Premium Sound – £6,099

Klipsch Cornwall IV

The Klipsch Cornwall IV dates from 1959 and takes its name from the two ways you can site it: in a corner or against a wall. It is the largest of the direct-radiating models, and the point at which the range starts to feel genuinely large-scale.

The woofer steps up to the K-33-E 15-inch fibre-composite unit, the same driver used in the bass horns of the La Scala and the Klipschorn, here loaded by a ported cabinet with front-firing Tractrix ports. Response is quoted at 34Hz to 20kHz, and sensitivity rises to 102dB, which is only a decibel or two below the fully horn-loaded models. Crossover points are 700Hz and 5000Hz, and the network borrows its voicing from the Klipschorn and La Scala.

Those two figures together are the argument for the Cornwall. You get output and dynamic ease approaching a fully horn-loaded speaker, from a cabinet that is 965mm tall and 643mm wide and does not need a corner. The front ports also mean it tolerates being close to the wall behind it, which is why it remains the practical choice for people who want the big Heritage sound in a room that cannot host a La Scala.

Buy Klipsch Cornwall IV at Premium Sound – £8,249

The fully horn-loaded models

Above the Cornwall, the bass driver stops radiating directly into the room and starts working through a folded horn. Cabinet volume increases sharply, and so does efficiency in the bass, where it is hardest to achieve.

Klipsch La Scala AL6

The Klipsch La Scala AL6 arrived in 1963 as a portable public-address speaker, commissioned so that a gubernatorial candidate could be heard outdoors. It has been a domestic speaker for most of its life since.

It is horn loaded across all three ways. The K-33-E 15-inch woofer sits behind a folded bass horn, the midrange uses a K-55-X 2-inch phenolic compression driver on an exponential horn, and the treble comes from a K-771 1-inch polyimide compression driver on a 90 by 40 degree Tractrix horn. Sensitivity is 105dB, crossover points are 450Hz and 4500Hz, and each cabinet weighs 91kg.

The low crossover point matters more than the headline sensitivity. At 450Hz, the horn takes over below the fundamental of most female voices, which means the entire vocal range is horn loaded and reproduced by a single driver. The result is a midrange with unusual coherence and very low distortion, the quality Paul Klipsch was chasing when he said that the midrange is where we live.

The trade-off is the bass. The folded horn in a cabinet this size cannot be long enough to reach the bottom octaves, and the quoted response stops at 51Hz. Some owners run the La Scala with a subwoofer for exactly this reason, though a fast, well-integrated one is needed to keep up.

Buy Klipsch La Scala AL6 at Premium Sound – £15,499

Klipsch Klipschorn AK7

The Klipsch Klipschorn AK7 is the original, in continuous production since 1946 and still the design the rest of the range is measured against.

The classic Klipschorn used the room’s corner as the final section of its bass horn, with the cabinet open at the back. From the AK6 generation onwards the low-frequency horn is fully enclosed, so the speaker no longer depends on the walls to complete the horn path, though it is still specified in eighth-space and still sounds most convincing tucked into a corner. Quoted response is 34Hz to 19kHz with 103dB sensitivity, and impedance is 8 ohms with a 4 ohm minimum at 50Hz.

The AK7 brings two changes worth noting. The midrange moves to a K-1133-HP 3-inch compression driver on the K-406 Tractrix horn, an inch larger than the AK6 driver, which increases the compression ratio at the horn throat and with it the available output. And the crossover points are the lowest of any passive model here, at 380Hz and 2900Hz, which keeps the horns working across the widest possible span.

There is also a redesigned rear input panel with both passive and active inputs plus a passive output, built to accept the optional Heritage Active Crossover. That unit was tuned specifically for the Klipschorn by Roy Delgado, and it applies time and phase alignment along with EQ correction, technology developed for the Jubilee. It is the single most significant upgrade path available in the range, and worth budgeting for if you are buying at this level.

Buy Klipsch Klipschorn AK7 at Premium Sound – £21,999

Klipsch Jubilee

The Klipsch Jubilee was Paul Klipsch’s last project, begun as a successor to the Klipschorn and finished by Roy Delgado after his death. It departs from the rest of the range in two structural ways.

First, it is a two-way. A single K-693 7-inch titanium compression driver with a 5-inch voice coil handles everything above 340Hz, which means the whole midrange and treble comes from one source with no crossover anywhere near the ear’s most sensitive region. Below that, dual K-283 12-inch woofers work into a patented horn-loaded vented enclosure, combining the efficiency of a horn with the extension of a vented alignment. Quoted response reaches 18Hz.

Second, the crossover is active and mandatory rather than optional. The Jubilee is supplied with its own active crossover and requires separate amplification for the high and low sections, with recommended power of 100W to 400W for the HF and 300W to 1200W for the LF. Sensitivity is quoted at 110dB for the high-frequency driver and 107dB for the low.

Running the crossover before the amplifiers rather than after them removes the passive network from between amplifier and driver entirely. The amplifier sees the driver directly, damping improves, and the designer gains precise control over time delay and phase between the two sections. This is the reason the Jubilee can hold a coherent image at levels where most systems begin to fall apart.

It is also 1752mm tall and needs a room to match, along with four channels of amplification. This is a project rather than a purchase, and it should be treated as one.

Buy Klipsch Jubilee at Premium Sound – £44,999

Which one suits your room

• Small rooms, or a first step into the range on stands: Rebellion. The only standmount here, and the one model that works on a shelf or in a system where floorstanders are not an option. Budget for solid stands and an amplifier with real current delivery.

• Rooms under about 20 square metres, or shelf and cabinet placement: Heresy IV. It is the only model here that works genuinely close to a wall and at low listening heights, and it is the natural partner for a low-power valve integrated.
• Most British living rooms, wanting full-range sound without a large footprint: Forte IV. The passive radiator delivers the extension the Heresy lacks and the cabinet is narrow enough to be unobtrusive.
• Larger rooms, or listeners who want scale and dynamic headroom without a corner-mounted speaker: Cornwall IV. 102dB sensitivity and a 15-inch woofer in a cabinet that can sit against a wall.
• Midrange purity above everything, in a room with good corners or long walls: La Scala AL6. Consider budgeting for a subwoofer if your listening runs to large-scale orchestral or bass-heavy electronic music.
• A dedicated listening room with usable corners: Klipschorn AK7, ideally with the Heritage Active Crossover as a planned second stage.
• A dedicated room, four channels of amplification and no upper limit: Jubilee.

Practical matters

Two points apply across the whole range.

The first is amplifier noise. At 99dB to 105dB, any hiss or hum in the chain is audible from the listening position when the music stops. This is not a fault in the speakers, it is the price of the sensitivity that makes them work, and it means a quiet preamplifier and a clean phono stage matter more than they would with a conventional design. It also means power is rarely the constraint. Amplifier quality, not amplifier watts, is where the budget should go.

The second is placement, particularly toe-in. Horns are directional by design, and the Tractrix profiles used across the range are specified with defined coverage patterns. Small changes in toe-in produce large changes in tonal balance and image width. Start with the speakers aimed at a point slightly behind your head, then adjust in small increments and listen for the moment the centre image locks and the top end stops sounding forward.

Get the amplifier matching and the toe-in right, and what these speakers do becomes obvious very quickly: music arrives with the effortlessness of a real instrument in the room rather than a reproduction of one, at any volume you care to use.