Audio glossary

Please visit this site for a glossary of audio terminology:
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Sound Lab

Why Electrostatic Loudspeakers?

A perfect loudspeaker would have the ability to move air effectively, yet have no mass of its own. Mass translates to coloration in reproduced sound because of mechanical distortion. Today's best loudspeakers have diaphragms that actually weigh less than air. The perfect loudspeaker is now within our grasp. Sound Lab's Electrostatic Loudspeakers (ESL) utilize diaphragm materials that were originally developed for the space program, and are just a few millionths of an inch thick. They have one of the lowest moving masses of any loudspeaker technology.

Another advantage of ESL tec hnology is that the driving force is distributed evenly, over the entire membrane. Conventional dynamic loudspeakers present the driving force, via a voice coil, only to the perimeter of the voice coil itself. This mechanical force is then coupled from the voice coil to the remainder of the diaphragm. For this coupling to occur, the diaphragm must be quite robust. This translates to a high mass diaphragm and all the mechanical distortion products that are a result of not driving the diaphragm evenly over its entire surface.

The larger surface area of Sound Lab's ESL driver can reproduce all frequencies from low bass to the super-sonic frequencies. No crossover is required; so all the limitations of crossovers used with dynamic driver technology can be avoided. In this manner, phase linearity distortion and amplitude variation, common to speakers with crossovers, can be avoided.

The Line-Source

Sound Lab speakers are based on a speaker topology known as the line-source. The best way to introduce radiated sound into a room is with a line-source because it more closely approximates the experience of a live musical event. A perfect line-source would extend all the way from the ceiling to the floor. In reality, the line-source in your listening room need not be quite that large appreciate the same results. With a line -stage, the sound level is the same, no matter whether you are in a sitting or standing position. As you move around in the room, the neither speaker tends to dominate the other. Also when you move closer to the line-source, the music doesn't seem to get that much louder. These are all characteristics shared with the live musical event.

Distributed Resonance

Sound Lab has a patented technology that helps eliminate two of the common problems with dipole speakers. This technology is known as "Distributed Bass Resonance" (DBR). Dipole speakers have resonant peaks at their lowers frequency extremes. They also suffer from cancellation, since the sound emanating from the front and the rear of the dipole speaker is 180 degrees out of phase.

DBR Technology divided the ESL panel into many smaller sections, thus avoiding the resonance problems with a large, uncontrolled ESL panel. This methodology effectively controls dipole cancellation in the bass region.

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Gilmore Audio

Gilmore Audio speakers are the direct result of a long-term dream. The dream is to reproduce the live musical event in the home environment. Although this dream may never be recognized in our lifetime, we believe that our speakers come closer to this goal than any others, regardless of technology or price. The secret is our unique and unconventional speaker design.

Of course, we all know the perfect loudspeaker (TPL) will never exist, but it's entertaining to dream what it might be, independent of any real-world constraints. TPL should have no mass, be capable of reproducing all frequencies from subsonics to ultrasonics with no frequency response variation. It should be 100% efficient (all power introduced into it should be directly converted to acoustical energy) and should not produce distortion of any type. It should be capable of an infinite sound pressure level (SPL) at all frequencies. TPL's dispersion should duplicate that of the original recorded instrument. The speaker's parameters should not change as the SPL increases.

So why are so many of today's speakers incapable of reproducing the live event? For the sake of our discussion, we will assume a state-of-the-art source much like the performance, such as an actual master tape. It makes no sense to talk about the best speakers without a comparable source. It seems most speakers fall into three main groups. Group One speakers portray an illusion of the live event, but only at low or less-than-realistic SPLs. Speakers in Group Two reproduce live event dynamics, but fail to convey t he detail of the original performance. The third group is "that which is and should never be." In this group, there is no hope of ever reproducing the original dynamics or detail.

Group One includes the best planar technology loudspeakers. Electrostatic (ESL) or planar magnetic (PM) electrostatic often create a most believable illusion of the live event. Their extremely low-mass drivers create impressive reproduction of live event detail, harmonic structure and nuance. Given a driver with sufficiently low mass, the manufacturer of an acoustic guitar's strings can be identified. The amount of rosin on a violin's bow can be perceived. These are nuances that today's best drivers can reproduce, except for dynamic drivers, usually characterized by paper cones, have too much mass to compete in this arena. Sadly, with all the beauty these planar speakers convey, they often fail miserably in their attempt to reproduce live concert dynamics. Typical SPLs that are encountered front and center at the symphony, or with a small, intimate jazz combo, average as much as 90 to 95 dB. Along comes the whack of a drum or the brash blat of a trumpet and a 20 dB dynamic overhead is required. The best of these speakers, severely compress past 105 dB, so there's no possibility of recreating the dynamics of the live event. In trying to reproduce the dynamic power of a live rock concert, for example, or music with dee p synthesized bass, they fail completely. A typical listening session starts with the volume turned up to a realistic level, which must then be reduced rapidly when a demanding musical passage occurs. Adding insult to injury, most speakers in this group require high input power levels and provide a difficult load for many less capable amplifiers.

Group Two are the high-efficiency dynamic and horn designs. As we mentioned, most dynamic drivers can't respond quickly enough to convey the detail of the original musical event. Horn speakers, for example, are a high-efficiency variation of a dynamic speaker and essentially suffer from this same limitation. To their credit, speakers in this group are historically easy to drive and require little power to convey realistic dynamics because they are so efficient. But the excitement of the live event is conveyed at the expense of the detail that defines the instruments being played. In addition, they are limited by the associated coloration and limited dispersion of the actual horn itself (and often, by inherent resonances). To varying degrees, horn loudspeakers introduce distortion not in the original recording, much as cupping your hands around your mouth "distorts" the sound of your voice.

Group Three is where the majority of speaker designs fall. We call this the "that which is, but should never be" category. These speakers have no hope of reproducing the original event's detail or dynamics.

Thus far, speaker design has been rife with compromises. For example, no speaker can be considered state-of-the-art unless the radiating element approaches the same low mass as the air it moves. Today's technology provides such materials. Yet, many less desirable options are employed. We believe a radical new approach is needed that bypasses current design compromises. The Gilmore Audio speaker employs many proprietary, unique and innovative technologies and designs to create a musical experience that represents the best of all worlds: the transparency and detail of the finest electrostats, the dynamic capabilities of sound reinforcement speakers and the ability to play remarkably deep, responsive and authoritative bass without a subwoofer! The Gilmore Audio speakers represent a paradigm change.

Welcome to the future and the new look of great sound.

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The Technology

Gilmore speakers are all full-range, planar, line-source dipoles.  

The Model 2 is down 3 dB at 17 Hz and the Model 3 is down 3 dB at 22 Hz. No subwoofers are required. In fact, many subwoofers do not have such a robust low-frequency extension.  

Gilmore audio speakers are planar designs. All drivers are mounted in the same plane on a single, very relatively thin panel. They do not have a conventional enclosure. The Model 2 panel is 1 1/8 inches thick.   The Model 3 is only 5/8" of an inch thick.

The speaker is a dipole, so it radiates sound equally from the front and rear of the panel. The Model 2 is 66 inches tall and the Model 3 is 44 inches tall. The speaker's drivers are arranged in a topology known as the line-source, since they launch a very tall vertical wave front. Sound is radiated over almost the entire vertical length of the speaker.

The Gilmore speakers can be experienced at Glacier Home Listening Rooms and affiliated dealers.

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