The origins of KLH Audio
KLH Audio Loudspeakers. KLH is an American company founded in 1957. Due to many innovations, they rapidly became the largest loudspeaker manufacturer in the world. They employed over 500 people and made over 30,000 loudspeakers per year.
KLH has pioneered many innovations. For example, They made the first high-selectivity FM receiver, with the Model 8. They also made the first full-range electrostatic loudspeaker. Moreover, they made the first Dolby-equipped reel-to-reel tape recorder. They have made some of the best-selling speakers in the world starting with the model 5. We also take a look at two of the most groundbreaking KLH speakers from the past.
The KLH Model 5 stand-mount speakers
The KLH model 5 is an acoustic suspension speaker. It is one of the most sought-after speakers among audiophiles. Consequently, it is still in production. The latest version has real wood veneers and cast aluminium speaker baskets. Notably, the design was developed by Henry Kloss one of the founders of KLH.
The KLH model five comes with three beautiful finishes. These include English walnut, West African Mahogany and Nordic Noir, giving you a choice to match any decor. Additionally, the Walnut version has a gorgeous stone washed linen grille cloth. The iconic mid-century design still has one of the most accurate and linear cabinets available today. The three-way acoustic balance control allows you to tailor the sound for difficult acoustic environments. The dedicated midrange driver has a die-cast aluminium frame and the tweeter has an aluminium face plate. Finally, the crossover has thirteen components including high quality iron-core inductors and Mylar capacitors.
Two way, KLH Model 3 bookshelf speaker
The latest KLH model 3 is a compact bookshelf speaker with a big sound. It can rival the biggest floor standers with its acoustic suspension design and audiophile performance. The diminutive size allows for placement closer to the wall or even on a bookshelf. it is the perfect solution for a smaller room. The Model 5 also comes with a slant riser base. Next, we look at one of the key historical speakers developed by KLH.
What is acoustic suspension?
Acoustic suspension, also known as closed or sealed box, is a type of speaker that does not have a bass port, hence it is airtight. They provide less bass for a given power but have reduced distortion. An acoustic suspension speaker was brought into production by Henry Kloss who gave his initial to KLH. This was later developed into the Model 7 in 1960. Acoustic suspension speaker cabinets have greater control over the bass response than bass-ported designs. However, they are less efficient than bass reflex designs, of the same volume. As a result, they need more power to drive them. The main advantage is less phase delay and accuracy problems. The Model 7 came out in 1960 and had some interesting features.
The historical model 7, from 1960
The aim of the Model 7 was to give better deep-bass response than the preceding Model six. As a result, it was twice the volume. The problem was that it needed more power to achieve this. Consequently, this led to greater distortion. However, there was a trade-off between deeper bass and the level of distortion. This only became a factor at higher volumes.
As most people listed at moderate volumes, it was not considered to be too much of a problem. The model sevens had two tweeters which gave them a wide dispersion and clear highs. The spacious sound was well-liked but not many were sold due to their price and size.
KLH electrostatic Model 9
The KLH model 9, Audio magazine October 1960.
The KLH Model 9 is a legendary speaker amongst audiophiles. The electrostatic design is highly sough after and considered to be the best sounding speaker ever made. The Model Nine was almost six feet tall but only 3″ deep. It had a hardwood frame that held it’s fabric grille in place. Notably there were two sets of radiator panels, one each for bass and treble. It had a built-in power supply and step up transformer in the base. The PSU produced 6KV. The panel layout was mirrored. The tweeter dealt with frequencies above about 2kHz while eight large diaphragms dealt with the rest of the frequency range. Notably, they needed careful positioning to get the best effect.
What is an electrostatic speaker?
Electrostatic speakers work in a completely different way than cone loudspeakers. They use a thin flat diaphragm that is made of a plastic material coated with something conductive, such as graphite. The diaphragm is mounted between two electrically conductive plates, known as grids. There is a small air gap between them. This allows the diaphragm to move the air to either side, to generate sound. This design can provide orders of magnitude less distortion than cone designs. However, it needs high voltages to operate. The surface of the diaphragm must have a constant and even charge. This is done by having the surface exhibit a high resistance.
The diaphragm is held at several thousand volts above the grids. The grids are driven by the audio signal in antiphase via a step up transformer. This causes the diaphragm to be modulated by the music. Electrostatic speakers are bi-polar in that the sound comes from both sides.
Advantages include very low distortion and a wide frequency response due to the low mass of the diaphragm, compared to a coned speaker. They can be full-range designs without a crossover. Disadvantages include difficulty of placement and a lack of bass response. They tend to have a higher bass roll-off than conventional speakers. They do however sound more natural with no booming. Finally if you are really into your bass, the current Kendal model is for you.
The KLH Kendal bass reflex floor-stander
The KLH Audio range also includes the Kendal speaker, a flagship model in the modern KLH range. It is a large, 3-way, bass reflex floor-stander. Detail is natural and bass is deep. There are two woven Kevlar bass units along with a 5.25″ mid-range unit. Moreover the tweeter has braided leads and an Aluminum dome. The faceplate is also metal and aids with linearity. The Kendal has 250 Watts of power handling and is available in walnut and black finishes.