General Asylum: REVIEW: Michael Green Designs Harmonic Feet Other by Jim Bookhard

What Are They? --

MGD Harmonic Feet are resonance control devices which are designed to replace the manufacturer installed feet on components (audio, video and professional) and couple a component to the surface beneath the component. In addition to ridding the component of mechanical energy, the Harmonic Feet will, as Michael Green of MGD describes, allow the component (and its inner components) to "harmonize" mechanically. This term "harmonize" will be more readily understood after reading about what is heard from their performance, and for a more complete technical explanation, you should ask their designer -- Michael Green. But, his basic description of how these devices work is that they "harmonize all the mechanical aspects of a component and of its parts".

In order to describe what these devices look like, visualize an MGD brass MTD (Mechanical Transfer Device), or any other cone. Now, at the "bottom" (pointed end of the cone), cut off about 1/4 inch of the brass so that from the side, the "bottom" of the cone now appears flat instead of pointed. Next, from the "bottom" end, ream out the cone, leaving a wall thickness of about 1/32 of an inch. The "top" of the cone remains flat, but a small screw hole is tapped for insertion of the original equipment footer screw from the bottom up into the component. Now you have some idea how a Harmonic Foot is designed and looks. From a two dimensional side profile view, a cone looks like a triangle and a Harmonic Foot would look like a trapezoid. The Harmonic Feet devices are well made, "weighty" and machined from solid brass.

Unlike the sharp pointed MTDs, the Harmonic Feet can stand on their ends by themselves which makes it easier to place them underneath components, if you do not screw them in, replacing the original equipment footers. Because the Harmonic Feet can be directly attached to components through the original footer screws and the surface contact area is larger, the component is less prone to movement when touched.

There are two versions of the Harmonic Feet -- "Small" and "Large". The "Small" Harmonic Feet are 3/4 of an inch tall and the top end has the same diameter as an MTD (one inch). The small end tapers to 1/2 inch in diameter. The "Large" Harmonic Feet are 3/4 inch tall, 1 1/4 inches in diameter at the top and taper down to 3/4 inches in diameter. Both are quite "weighty" and, like MTDs, are machined to their respective sizes from solid brass.

Using Harmonic Feet With "Clamped" Audio Components --

Although, there are plans for more "sizes" of Harmonic Feet, I have used the two currently available versions of the Harmonic Feet -- "Small" and "Large". When clamping components in my system, I have found that the configuration yielding the most preferable sound was when placing 3 MTDs underneath each component and one Harmonic Foot on top. The "Large" version Harmonic Foot yielded more harmonics than the "Small" version and presented a sound that more closely resembled the harmonics of real music from all my audio system components -- amps, CD player, preamp and tuner -- although I did not purchase enough of the "Large" Harmonic Feet, I actually preferred one "Small" Harmonic Foot on top of my Magnum Dynalab clamped tuner. Hearing a difference between both versions of the Harmonic Feet is easily demonstrated when clamping in the previous manner. As I said, I personally preferred the sound using the "Large" Harmonic Foot on top of the clamped component, but, again, this is a personal preference because I prefer a harmonically rich, yet detailed sound.

When listening to stereo speakers in the nearfield (around 4 1/2 to 5 feet away from the mid plane), a localization problem usually occurs on some recordings when there is music recorded on just one channel -- the phenomenon that is created is that the sound becomes localized right at the left or right speaker, rather than having a more "accurate" spacing in the soundstage. When listening to speakers much further away from the listener, this phenomenon does not occur. This will only occur when listening very close in the nearfield on some recordings and it depends on how the recording was mixed. When clamping, using one Harmonic Foot on top and three MTDs on the bottom of the components, this localization of sound on a few recordings turns into a sense of the instrument being accurately placed in the soundstage and sounds more realistic, even with speakers as close as 4 1/2 feet away. The overall soundstage is more coherent, instruments sound more real, front to back and side to side layering is improved and background details become more prominent in the musical presentation. Also, the detail is increased from the lowest bass through the highest frequencies. And, for those who think imaging is important, instruments are more accurately spaced across and within the soundstage with the Harmonic Feet in the system versus just using MTDs. Vocals are clearer, as are all other instruments.

The first and most noticeable improvement brought on by the use of Harmonic Feet is the improved harmonic structural fullness in the bass, with no bloat anywhere in the bass region. Bass "weight" in the lowest octave of bass response is increased and the mid bass sounds more natural.

"Clamped" vs. "Unclamped" CD player audio performance --

Using two "mechanically tuned" CD players (a Parasound C/DX-88 and a Marantz CD-67), I compared performance using 3 "Small" Harmonic Feet on an unclamped CD player (the Parasound) against a clamped CD player (the Marantz). By "mechanically tuned", I am referring to a recommended mechanical tweaking technique that Michael Green of MGD uses to get the best performance out of a component. The more "mechanically tunable" the component, the better this tweaking technique works. Components which have been properly mechanically tuned sound richer, have more accurate harmonic structures, more detail, possess no edginess to the sound and simply sound more musical. Even older CDs from the late 80s or early 90s take on an analog sounding quality. Mechanical tuning itself is a relatively simple procedure and involves "tweaking" the component chassis and circuit board screws as well removable of as any unnecessary wiring harnesses inside the component. My Marantz was mechanically tuned by Michael Green when I purchased it from him employing brass standoffs on the circuit boards and brass screws around the chassis and the transformer was refitted directly to the bottom chassis versus on the circuit board -- I personally mechanically tuned the Parasound myself, but it is not as extensively tweaked mechanically as the Marantz. Both have some unnecessary circuitry (i.e., headphone jacks output, which I do not use) disengaged. Some CD component transport screws can be tweaked while others cannot and this is "player dependent". When in doubt, it's best to leave the transport screws alone -- i.e., the Marantz transport screws can be mechanically tweaked, but the Parasound's cannot.

Each of the above players has outstanding sonic characteristics when mechanically tuned, clamped or unclamped. Using the MGD Justaracks with the MDF shelves (also mechanically tuned by using only hand tightening of the bolts supporting the shelves -- a "tightly" bolted together, rigid JustaRack will not yield the best sonic tonal characteristics from components placed on its shelves -- that's just the way they are designed by Michael Green; I have personally seen his JustaRack and it is very "loose", as are mine), the Parasound actually sounds better using just 4 MTDs on its chassis, when clamping. The Marantz sounds better using the one "Large" (again, this was my sonic preference) Harmonic Foot on top and three MTDs on the bottom configuration for clamping. When clamping the Parasound (which normally sounds better than the Marantz) using one "Small" Harmonic Foot on top and 3 MTDs on the bottom, the powerful bass of the Parasound flattened out, just like the sound you get when you overdampen a component chassis. The basic sonic signature of the Parasound is that of richness, detail and powerful bass. The basic sonic signature (prior to application of Harmonic Feet or MTDs) of the Marantz has it sounding somewhat less harmonically rich, a more extended top end and tighter bass than the Parasound's basic sonic signature. However, both players are capable or extraordinary detail, harmonic structures and soundstaging capabilities when properly mechanically tuned. As to which player sounds "better" is a matter of preference. When clamping the Marantz, using one "Large" Harmonic Foot on top and 3 MTDs on the bottom, the reverse of what happened with the clamped Parasound occurred -- the bass became fuller, richer and more accurate.

Since I like the sound of the clamped Marantz better than the Parasound, when clamped using MDF shelves, I left it clamped in my audio system. I placed the Parasound on a separate shelf, unclamped, with just 3 "Small" Harmonic Feet underneath. In a listening comparison, the performance of both players was too close to judge which sounded better. As a matter of fact, the two players now sounded remarkably alike, possessing similar sonic signatures. The Parasound sounded just as extended on the top end and the Marantz was just as rich sounding and possessed the same "weight" in the bottom end as the Parasound, while its top end was as mellow as the basic sonic signature of the Parasound.

The point of this subjective listening test was that experimentation with different configurations of Harmonic Feet and MTDs is encouraged to determine which sounds best on which component. Michael Green can help in assessing what configurations would be appropriate for any given component, including pro gear like (i.e., guitar head amps). In addition, what the component is resting upon must be taken into consideration. The Harmonic Feet will work well when placed on ANY hard surface. The MTDs tend to yield the best sonics on MDF and low mass hardwood surfaces.

"Unclamped" Audio/Video Component Performance --

In my small home theater in my bedroom (separate from my audio system), I tried the "Small" Harmonic Feet underneath every component to assess performance with each. The one sonic characteristic that stood out when used with every component was the dramatic increase in bass response and weight. The DVD player, the A/V processor, the crossover, the line conditioner and the subwoofer amp have all been "mechanically tuned", inside and out. The receiver's external chassis screws have also been tweaked. The Harmonic Feet can also be placed underneath a TV set, but mine weighs too much for me to singularly manage to place them up on the Harmonic Feet. The audio results I got were similar to my audio system -- better harmonics, deeper and more accurate bass, more detail, better vocal clarity and "larger" surround field effects than those yielded using just MTDs. On DVD videos, the sound improved similar to the sonic improvements I heard in my audio system. The apparent size/space of the room also enlarged sonically.

On video, the picture's colors were more pronounced on both digital cable (no DSS in my condo) and on DVDs. In addition, like the seeming contradiction in audio listening where bass got richer but remained tight, the picture not only got better in terms of color but also in terms of overall detail. More details, especially in background scenery, were brought out. Again, the point here is that underneath every component I placed the "Small" Harmonic Feet, there was an improvement in audio and/or video performance. Since I only purchased two sets of the "Small" Harmonic Feet, I finally left the two sets of the DVD player and the digital cable box, since those are the two "sources" in the home theater.

Conclusion --

The Harmonic Feet do not totally replace MTDs, as explained, when clamping components. But, when used on unclamped components, cones used alone cannot compete with the performance results of the Harmonic Feet. I compared them against Audio Selection Cones, Polycrystal coated brass cones, Simply Physics cones, original aluminum Tip Toes, TenderFeet, brass AudioPoints (which by the way, do not sound the same as MTDs -- the AudioPoints sound is slightly "cloudy" in close comparison) and the brass MGD MTDs. Unlike MTDs, the Harmonic Feet devices work much better with components that do not respond well to mechanical tuning or cones. One generalization that can be made about the Harmonic Feet is that they do not seem to be nearly as fussy about the weight of a component, in order to get good results, as cones are. As a matter of fact, they seem to work very well with higher mass components.In a comparison using MTDs versus Harmonic Feet under my digital cable box, MTDs made a small improvement sonically and visually to the picture, but the Harmonic Feet performance improvement was readily noticeable. They are designed to work under any device that has a motor, reportedly by Michael Green, making the device operate more efficiently, but I have not verified this by using them under any appliances nor my computer. But, I can say that they do bring you quite a few steps closer to the sound of real music and will definitely enhance your video experience.

REVIEW: Michael Green Designs Harmonic Feet Other Review by Jim Bookhard at Audio Asylum