The KLH Model Five is a three-way acoustic-suspension floorstander that revives one of the most storied names in American loudspeaker history and applies contemporary driver and cabinet engineering to a design philosophy first popularized in the late 1950s. For the experienced listener, the Model Five is an object lesson in how deliberate engineering choices, sealed-box loading, treated pulp-paper cones, an aluminum dome tweeter, and a user-adjustable high-frequency control, all combine to produce a specific and repeatable sonic character. This deep dive breaks down every element of that engineering and, just as importantly, teaches you how to read the specifications so you can match the speaker to your amplifier and your room.
The Core Engineering: Acoustic Suspension
What is acoustic suspension, and why does KLH use it?
Acoustic suspension is a fully sealed cabinet design in which the trapped air behind the woofer acts as a spring that controls the cone's motion, and KLH uses it because it is the defining engineering principle of the brand. In a sealed enclosure there are no ports or vents, so the compliance of the enclosed air becomes an active part of the woofer's suspension system. That air spring is highly linear, which means the cone is restrained symmetrically as it moves in and out. The audible result is very tight, accurate, low-distortion bass that stays clean even at high volume. KLH, founded in 1957 by Henry Kloss, helped bring this topology to prominence, and the modern KLH Audio company builds the Model Five specifically to carry that sound forward.
What are the trade-offs of a sealed box versus a ported design?
The main trade-off is that acoustic-suspension designs tend to have slightly lower sensitivity than ported designs, so they reward a capable amplifier. A vented box uses a tuned port to reinforce output near the tuning frequency, which can extract more apparent bass and higher efficiency from a given cabinet, but often at the cost of group delay and less controlled low-end behavior below the tuning point. The sealed Model Five gives up a little efficiency in exchange for a gentler low-frequency roll-off, superior transient control, and deeper extension from a comparatively compact cabinet. In practical terms this means the Model Five sounds composed and articulate in the bass where a ported peer might sound looser or boomier, and it is why the amplifier pairing discussion later matters so much.
The Drivers: Materials and Design
What is the woofer made of, and why does it matter?
The woofer is a 10 inch pulp-paper cone loaded in the acoustic-suspension configuration, and the material matters because treated paper pulp is light and inherently well-damped. A light cone accelerates and stops quickly, which aids transient accuracy, while the self-damping nature of paper suppresses ringing and breakup modes that can add coloration. KLH voices this pulp-paper cone for a natural, uncolored tone rather than an artificially etched or hyped presentation. Paired with the air-spring loading of the sealed box, the 10 inch woofer delivers bass that is both extended and disciplined.
What does the reverse-roll rubber surround do?
The reverse-roll rubber suspension is a surround oriented to control cone motion more precisely and lower distortion. The direction of the roll influences how the surround stores and returns energy as the cone travels, and reversing it helps keep the cone's excursion linear and symmetrical. Combined with the linear air spring inside the sealed cabinet, this surround geometry is part of why the woofer produces such low-distortion output across its operating band.
What is the midrange, and why a dedicated 4 inch driver?
The midrange is a 4 inch pulp-paper cone, and a dedicated midrange exists because the Model Five is a genuine three-way design that hands the critical vocal and instrumental band to a driver optimized for it. By offloading midrange duties from the 10 inch woofer, the design keeps the large cone focused on bass, where its mass and area are assets, while the smaller 4 inch cone handles midrange frequencies with the light, agile behavior that band demands. The shared pulp-paper material also keeps the tonal character consistent between the woofer and midrange, so there is no abrupt change in voicing as the music passes from one driver to the next.
Why an aluminum dome tweeter instead of a soft dome?
The tweeter is a 1 inch anodized aluminum dome, chosen because the metal dome is light and extremely rigid for extended, detailed treble. Rigidity pushes the dome's primary breakup mode well above the audible range compared with softer materials, allowing the aluminum dome to behave as a true piston across its passband and reproduce fine high-frequency detail cleanly. The anodizing further stabilizes the surface. The result is treble that reaches the full 20 kHz upper limit of the speaker's stated response with resolution and air, while the adjustable Acoustic Balance Control lets you keep that detail from becoming fatiguing in a bright room.
Crossover, Tuning, and the Acoustic Balance Control
Where does the crossover split the signal, and why there?
The crossover divides the music at 380 Hz and 2,850 Hz, sending the lowest frequencies to the 10 inch woofer, the midband to the 4 inch midrange, and everything above to the aluminum dome tweeter. The 380 Hz lower crossover point is deliberately low, which keeps the male vocal fundamentals and the body of most instruments on the dedicated midrange rather than the large woofer, preserving clarity and dispersion. The 2,850 Hz upper crossover hands off to the tweeter well below the ear's region of peak sensitivity, so the transition happens where the human ear is more forgiving of any phase or level discontinuity. Together these frequencies partition the audio band so each driver operates where it performs best.
What does the Acoustic Balance Control do?
The Acoustic Balance Control is a 3-position switch on the speaker that raises or lowers the high-frequency level in small steps, letting you tune the brightness to your room and your taste. It is a KLH signature carried over from the original Model Five. In a room with hard floors, glass, and bare walls that emphasize treble, you can step the level down for a more relaxed balance. In a heavily furnished, carpeted, curtain-lined space that absorbs the highs, you can step it up to restore air and presence. This is a genuinely useful voicing tool that lets the same speaker sound correct in acoustically different rooms without external equalization.
Cabinet, Bracing, and Physical Design
Why does the sealed cabinet need to be so well built?
A sealed cabinet must be airtight and rigid because the enclosed air is an active part of the woofer's suspension, so any leak or panel flex directly degrades the bass control. If the box loses its seal, the air spring softens and the tuning shifts. If the walls resonate, they radiate energy that muddies the sound the drivers are trying to produce. The Model Five is built to preserve the integrity of that sealed volume, which is central to why acoustic-suspension bass sounds as tight and low in distortion as it does. Each cabinet weighs 44 pounds, or 52 pounds with the riser base, and that mass reflects solid construction.
What does the slant-riser base actually accomplish?
The included slant-riser base is an angled plinth that tilts the speaker back slightly to time-align the drivers at seated ear height, while also adding stability. Because the woofer, midrange, and tweeter are physically offset on the baffle, tilting the cabinet helps the acoustic output of the three drivers arrive at your ears in better time coherence. With the riser the speaker stands 34.25 inches tall; without it the cabinet is 26 inches tall, which is worth knowing if you intend to place it on a different surface or integrate it into existing furniture.
What finishes and cosmetic options are available?
The Model Five is offered in English Walnut, Nordic Noir, and West African Mahogany, with grilles that attach magnetically. These finishes reflect the real-wood-veneer heritage of the KLH name, and the magnetic grilles let you listen with the drivers exposed or covered without visible mounting hardware. The 10 year warranty backs all of it.
Reading the Specifications: Amplifier and Room Matching
What does a sensitivity of 90.5 dB mean in practice?
A sensitivity of 90.5 dB (2.83 V at 1 m, in-room) means the speaker produces 90.5 decibels of output at one meter when fed the standard 2.83 volt reference signal, which is a genuinely efficient figure for an acoustic-suspension design. Sensitivity tells you how loud the speaker plays for a given amount of power. Because sealed designs often sacrifice some efficiency for their bass quality, seeing 90.5 dB here is reassuring, as it means the Model Five does not demand extreme amplifier power to reach satisfying levels. That said, headroom always helps a sealed box deliver clean transient peaks in the bass.
What does the 6 ohm nominal impedance with a 3.5 ohm minimum tell me?
The 6 ohm nominal impedance with a 3.5 ohm minimum tells you the electrical load the speaker presents to the amplifier, and it indicates a load that most competent amplifiers will drive comfortably while still asking for a stable output stage. Nominal impedance is an average figure, but the minimum matters because that is where the amplifier must supply the most current. A 3.5 ohm dip is moderate and manageable, though it is why pairing the Model Five with an amplifier that is comfortable delivering current into lower impedances will give you the most effortless dynamics. Within the KLH range this is a friendlier load than the 4 ohm Model Seven, which asks more current of the amplifier.
How much amplifier power should I use?
KLH recommends 20 to 200 watts, which gives you a wide and practical window for amplifier selection. The 20 watt floor confirms the Model Five is efficient enough to sing with modest power, while the 200 watt ceiling shows how much clean headroom the drivers and sealed alignment can absorb. For an acoustic-suspension speaker, erring toward the upper portion of that range is worthwhile, because generous power reserves let the woofer's air spring do its job during demanding bass passages without the amplifier clipping. Any high-quality amplifier that lands within this window and remains stable into the impedance minimum is a sound match.
What does the 42 Hz to 20 kHz frequency response imply for placement?
The stated response of 42 Hz to 20 kHz (plus or minus 3 dB) tells you the speaker reaches genuinely deep bass and extends fully to the top of the audible treble, and the 42 Hz bottom end has direct implications for placement. Because sealed boxes have a gentle low-frequency roll-off rather than the steeper cutoff of a ported design, room boundaries reinforce the bottom octaves in a predictable way. Placing the Model Five closer to a wall will lend additional low-frequency reinforcement, while pulling it into the room tightens and leans out the bass. Use that behavior, alongside the Acoustic Balance Control for the treble, to dial the tonal balance to your space.
Where the Model Five Sits in the KLH Lineage
How does the Model Five relate to the Model Three, Four, and Seven?
The Model Five is the three-way floorstanding heart of KLH's acoustic-suspension lineup, positioned above the smaller Model Three and Model Four and below the larger Model Seven. It carries the direct lineage of the original Model Five, including that signature Acoustic Balance Control, and reintroduces the classic three-way floorstander with modern drivers and cabinetry. The Model Seven scales the concept up with a larger woofer in its own sealed sub-enclosure and a more demanding 4 ohm load, while the compact models bring the sealed-box philosophy to smaller rooms. The Model Five sits in the sweet spot of that family, offering full-range floorstanding performance rooted entirely in the sealed-box engineering that defines the brand.
Conclusion
The KLH Model Five is a cohesive expression of acoustic-suspension design, from the linear air spring behind its 10 inch pulp-paper woofer to the rigid aluminum dome tweeter and the room-adaptive Acoustic Balance Control. Every specification, the 90.5 dB sensitivity, the 6 ohm load with its 3.5 ohm minimum, the 20 to 200 watt window, and the 42 Hz to 20 kHz response, points back to the same engineering intent: tight, low-distortion, honest sound that rewards a capable amplifier and thoughtful placement. Backed by a 10 year warranty and the heritage of one of America's storied loudspeaker names, the Model Five earns its place at the center of the modern KLH range.