The Woofers are 15" paper cone type with extremely large and heavy 20 pound magnets, working on a 4" ribbon wound voice coil. This speaker, when used in a ported cabinet, has very high efficiency, and also an extended coverage from the bass into the lower mid range. Two are tied in parallel to offer even better bass response, which also results in a 4 ohm impedance, matching better with today's solid state amps. Part of the reason for the smooth response and low distortion of this system is this extended range aspect of the woofers.
The Mid-range Compression Driver has been super selected to be the sweetest sounding mid range and lower highs than any other driver of any type we have auditioned. It has a 1 7/8” diaphram, and a neodymium magnet assembly for very high efficiency, and smooth response covering from the mid-mid range up to the lower high range. The diaphragm is of a polymer type, which is much smoother and sweeter sounding than the typical aluminum or titanium metal for this part.
This is an unorthodox use for the typical home music system, which almost universally utilyze cone mid-ranges, but we have dared to depart from the doctrine, for the sake of musicality and sonic purity. Also, the typical practice of multiple midrange drivers, in order to get some “punch” in loud passages of music with cone drivers, is not necessary here. The single compression driver has way more “punch” that you will ever need, and lower distortion, at all levels of sound.
The Horn (See image at left) Linn Audio has recently developed a new, proprietary horn, made from all wood (smoother sounding than the typical plastic or aluminum horns) and totally free of any resonance problems. The shape of the horn is also unique. It is specifically designed for home audio use (most stock horns are intended for performance and theater use) in that it has a very broad polar dispersion (which is more characteristic of cone drivers) so that it does not "beam" high frequencies (again, typical of most stock horns) and thereby provides a very broad "sweet spot" for the listener.
It should be noted that engineers have long recognized that compression driver/horns have much lower distortion and more musicality than cone type midrange drivers. But manufacturers began to design away from them after the 1960’s, primarily due the high cost of compression drivers, vs. the cost of cone mid-ranges. But today’s high-end manufacturers have continued to specify cone midrange drivers, even when the lowest cost is not the primary concern. This, we believe, is just a “follow the leader” approach, and continues to be the practice because (it is believed) that this is what people are used to seeing, and expect in a system. We know what we hear, and have selected the compression driver/horn configuration for the Reference Granite based on long listening experience, and know “in our hearts” that a horn system is superior to cone midrange configurations.
A Few More Words About Horns: A 100% efficient speaker system has theoretically zero distortion. Horn systems are approx 20% efficient, cone speakers are 2% efficient. Horn systems are capable of giving a closer approximation of musical reality. With precision alignment, their performance achieves the highest performance in linearity, fidelity, dispersion, efficiency and power. Horn systems are expensive to manufacture. Quality compression drivers are machined to exact tolerances within microns. Unfortunately today, selling is driven by marketing, not consumer understanding.
So we think that our somewhat unorthodox employment of the compression driver/horn for the midrange in the Reference Granite Speaker system makes the most sense, in today’s high-end market, and is a big reason why we believe that there is no better sounding system on the market today, regardless of price.
Horns have very special properties, including lower distortion than conventional drivers, faster transient response than conventional drivers, and are easier to drive at high SPL's than conventional drivers.
Lower distortion at a given SPL: For an equivalent SPL, horns require a smaller diaphragm, and since distortion is directly proportional to the size of the diaphragm, a large diaphragm electromechanical transducer (conventional driver) has to move much more than a horned diaphragm in order to create the same SPL (sound pressure level). The larger the excursion, the worse the distortion. So, for a given SPL, a horn loaded system will generate much lower distortion than an electromechanical transducer.
Faster transient response: Since the diaphragm is smaller, it is lighter and thus it accelerates and decelerates faster. This, in the real world means superb, fast snappy transients. As the excursion of the diaphragm is very small as compared to an electromechanical transducer, the voice coil is much smaller and again, this translates to a lower moving mass and again, results in fast transients.
Higher SPL's with a given input wattage: Small voice coils also take full advantage of the flux in the pole piece gap. This increases the efficiency of the transducer allowing the amplifier to work with greater ease. Since the amplifier has more headroom and the driver handles peaks and high outputs more efficiently, horns are able to produce much higher SPL's before they distort.
Thus, in the normal operating range, horn designs are faster, more dynamic, have a better transient response, have less distortion, and are easier for an amplifier to drive than conventional driver designs.
So, with the use of a horn, you feel the music, you become part of the music, and the music becomes part of you. The full-range phase coherent wave front of horns produces a solid image and presentation, as opposed to the phase impaired, smeared, and diluted imaging of typical low efficiency conventional driver designs. Horns will never sound veiled or compressed. The performers will be there, in your room, performing for you in the same way and location as the original recording venue. If the performer was six feet from the microphone during the recording session, he will be six feet away from you when the performance is reproduced through your system, not fifteen feet behind the speakers. Why would one want the performers to be fifteen feet behind the speakers if that was not how the material was recorded? We want the performers to be in the same room we are in, in front of us, so that we can feel the music, front row center.
Due to their inherent benefits of low distortion, high efficiency, fast and accurate transient response, and wide dynamic range, horn loudspeakers provide a pure, unadulterated musical presentation, a more organic and natural recreation of the acoustic event. As a result, each different musical selection is portrayed with its own character and life, not that of the playback medium.
The Tweeter is a ribbon type, also with a very heavy and powerful neodymium magnet, which is unusual for tweeters. We have found that this tweeter is very smooth and not at all harsh, and brilliant without being fatiguing. It also has a good lateral coverage for flexibility in the sweet spot, and restricted vertical coverage to avoid room reflections. The efficiency is quite high, for a tweeter of this type, being similar to the woofers' 97 db, so that the system has a good sensitivity match of the two drivers. The best news is the very extended range of this device, which goes all the way up to 40,000 hz!
There are two 6" diameter ports in the cabinet front baffle, that are precisely placed on each cabinet at optimal positions for the best bass response, extended all the way down to 18 hz with no "bumps" along the way that can cause "boominess" in the low-end range of sound. The tubes are machined out of the same high-density MDF as the rest of the cabinet, and finished to match the surrounding cabinet surfaces, in order to give a pleasing consistent look to the entire cabinet front.