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Gilmore Audio
(Affectionately known as "Speaker of Mass Destruction")

Gilmore 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 other, regardless of technology or price.   The secret is our very unique and unconventional speaker design.

Before we discuss available real-world speaker technology, we should first define The Perfect Loudspeaker (TPL).  Of course, we all know the TPL will never exist, but it's still quite entertaining to dream what it might be given enough technology and the ability to throw out the limitations of physics.

So, TPL should have no mass.  It should be capable of reproducing all frequencies from the sub-sonics to super-sonics with no frequency response variation.   It should be 100% efficient; meaning all power introduced into it should be directly converted to acoustic energy.

The TPL should not produce distortion of any type.  It should be capable of infinite sound pressure levels (SPL).  The TPL's dispersion should duplicate that of the original recorded instrument.   The speaker's parameters should not change as SPL increases.

So why do so many of today's speakers fail to reproduce the sonic illusion of the live event?  For the sake of our discussion, we will assume a state-of-the-art source, much like the performance of an actual master tape.   It makes no sense to talk about the best speakers without the best source.  

It seems most speakers have fallen into three main groups.  The first group is those that can often portray the illusion of the live event, but only at low or less than realistic sound pressure levels (SPL).  The second group can easily reproduce the dynamics of the live event, but fail at their attempt to convey the detail present in 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 of the original event.

The first group include the best planar technology loudspeakers.   Electrostatic (ESL) or planar m agnetic (PM) electrostatic often create a most believable illusion of the live event.  Their extremely low-mass drivers are capable of the very impressive reproduction of the detail, harmonic structure and nuance of the live event.  

Dynamic drivers, usually characterized by paper cones, or the like, have far too much mass to compete in this arena.  Given a driver with sufficiently low mass, the actual manufacturer of an acoustic guitar's strings can be identified.  The amount of rosin on a violin's bow can be perceived.  These are all characteristics of today's best driver technology.  

Sadly, with all the beauty these speakers can convey, they often fail miserably when they attempt to reproduce the dynamics of a live concert.  The typical SPLs encountered, front and center at the symphony, or even a small, intimate jazz combo, will average as much as 90 or 95 dB.  Along comes the whack of a drum, or the brash blat of a trumpet, and short-term SPL requirements will often require at least a 20 dB dynamic overhead.  

The best of the ESL, or ribbon speakers, will severely compress past 105 dB, so there's no possibility of reproducing the dynamics of the live event.  When trying to reproduce the dynamic power of a live rock concert, or music with deep synthesized bass, these speakers fail completely. A typical listening session starts with the volume turned up to a realistic level, only to be reduced rapidly when a demanding musical passage occurs.  

Adding insult to injury, most speakers in this group require very high input power levels and provide a very difficult load for many less capable amplifiers.

The second group includes the high efficiency dynamics and horn designs.  In most cases, the speakers in this group have no problem reproducing the dynamic range common in the most dynamic music.  

The excitement experienced at the live event is conveyed in part by reproducing an instrument's actual dynamics and is a wonderful and emotional experience. In this case, it's done at the expense of the detail that defines that instrument.  Dynamic speakers can't move enough mass quickly enough to convey the original musical event.  

Since horn speakers are a high-efficiency variation of a dynamic speaker, they don't have so much mass to move, but they a re limited by the associated coloration and limited dispersion of the actual horn itself (and often, by inherent resonances).  The horn loudspeakers introduce, to varying degrees, distortion not in the original recording, much like what happens to the sound of your voice when you cup your hands around your mouth.  

To their credit, speakers in this group are historically easy to drive and require little power to convey realistic dynamics.

The third group is sadly where the majority of speaker designs fall. This is what we call the "that which is, but should never be" category. These are the speakers that have no hope of reproducing the original event's detail or dynamics.  Most would consider this very strong assertion, yet there is great wisdom in the quest to understand the reasoning behind this assertion.

 Today's technology allows us lower mass materials than ever before.  No speaker can be considered state-of-the-art unless the radiating element approaches the same low mass as the air it moves.

We believe a radical new approach is needed.  Speaker design is rife with compromises.  It's high time traditional loudspeaker design is rejected in favor of an approach that bypasses so many of these design compromises.  

At Gilmore Audio, we don't believe in the endless attempt to work within the compromises of traditional speaker design.  Our designs are not revisited sixties or seventies technologies.   If we find a compromise, we do our best to reject the obsolete, flawed technology and find what's often a radical approach completely without compromise.        

The Technology (preliminary)

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 inch thick.  The Model 3 is only 5/8 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.

Mark Gilmore in Glacier Park, Montana summer 2003

 

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info@glacieraudio.com       P.O. Box 7668 Kalispell, MT,  59904  1-888-291-8501