Positive Feedback ISSUE 54
Image Stabilizers/Sound Diffusers
as reviewed by Kent Johnson
One of the most impressive demonstrations at last Fall's Rocky Mountain Audio Fest was found in the Grant Fidelity room. As demo tracks played, Ian Grant moved a pair of his Image Stabilizers in and out of the center area behind the equipment.
When the Image Stabilizers were moved into position, the center image became more focused, richer, easier to understand, and, seemingly, louder. When they were removed, these improvements disappeared leaving the system—regardless of what components were in use—sounding slightly faded by comparison. The theory behind the stabilizers is that they block indirect sounds, such as reflections coming off of the speaker cabinets, from interfering with the direct sounds coming from the drivers themselves. This has the effect of making the center image sound noticeably clearer.
This effect was readily heard by every person who was in the room. I did not encounter any visitor who failed to hear a difference. It was a surprisingly unsubtle and wholly positive change.
I requested a pair of the Image Stabilizers for review and in late-January they arrived.
As I used these components—between and behind my speakers—they are considered Image Stabilizers. Used in other room locations and ways, they are considered Sound Diffusers, hence the duality of the name.
Each stabilizer measures approximately 23.5 inches high by 21.25 inches wide by 4.75 inches deep. (Their actual measurements are in millimeters as they are made in China by Nobility Furnishings Design. I find inches easier to visualize.) The weight per stabilizer is 21.5 pounds. The fit and finish is superb. The corners are mitered box joints and they fit flawlessly. The finish is dark walnut, which works fine in my room as nothing coordinates anyway. The price is $275 per stabilizer
I asked for two stabilizers due to the height of my Magneplanar MG1.6 speakers. I think most floor standing speakers will require a pair as well. A single stabilizer should work well with small monitor speakers but will require a stand of some sort to raise it to speaker height.
The front of each stabilizer is a series of five pairs of scientifically-calculated recessed openings, each measuring approximately 21.75 by 1 5/8 inches. The outer two openings are recessed approximately 3/8 inch from the front edge of the stabilizer. Each successive pair is farther back by approximately ¾ of an inch ending with the middle pair at a depth of 3.75 inches.
Unlike every other piece of equipment that I have reviewed these do not require any burn-in time. So it was possible to try them in my system immediately.
I began by simply stacking the pair of stabilizers as close to the rear wall as the speaker and AC cabling allowed, centered between my speakers. This placed them about 60 inches behind a plane through the Magneplanar 1.6s.
The stability was good but not great. I have carpet over an uneven concrete floor. I was not worried about the stabilizers toppling over; I was worried that I would inadvertently bump into them and send them down on the amp stand. I have some homemade spiked speaker/equipment bases that I made from 2.5-inch thick cutting boards. The spikes allow these boards to be firmly in contact with the concrete beneath the carpeting, so I put one in place and repositioned the stabilizers on top of it. (You can see it in the photo.) This base, and blue masking tape, made it easy to make repeatable small adjustments in the position of the stabilizers.
The base helped stability quite a bit. It also raised the stabilizers slightly, which I think was also a positive in my set up.
I began listening with the Rudy Van Gelder remastered version of Dexter Gordon's Gettin' Around (Blue Note 0946 3 37757 2 5). This recording places Mr. Gordon inside the left speaker, the piano and vibes in the center, the drums in back of the piano (they extend pretty much speaker to speaker), and the bass to the right of center.
With the stabilizers in place, the piano, which is fairly low in level even when it solos, had better center-image focus and seemed very slightly louder. Its lines were easier to follow. The difference was pretty subtle but definitely positive. The vibraphone also sounded more three-dimensional with the stabilizers in place. Dexter's trumpet, on this recording, had a slightly abrasive quality to its sound that I found somewhat odd, given how well he is recorded on other RVG reissues.
Ann Hampton Calloway's Signature CD (N-Coded Music NC-4227-2) exhibited more precise low-level detail than I had noticed before enhancing the already excellent realism of her performance.
The biggest improvement I heard came while listening to "A Song for Francesca" from Gothic Voices (Hyperion GAW21286). Gothic Voices consists of five vocalists who sing in various combinations—solo, duo, trio, etc. There was noticeably better clarity to each voice with the stabilizers in the system. By clarity, I mean not only intelligibility but a better sense of the voice occupying a clearly-defined three-dimensional space within the central soundstage while being separated from the other voices around it.
These same sorts of improvements were heard to varying degrees with all the music that I listened to.
At this point, I began to move the stabilizers forward in small increments. When they were located about 50 inches back from the plane of the MG1.6s, there was an overall improvement in focus, not only for the central image, but for the entire soundstage itself. The abrasiveness that I had noticed on the Dexter Gordon CD was almost entirely ameliorated. There was a better sense of the overall performing space being inhabited by the Gothic Voices.
It happens that my speakers are almost exactly 100 inches apart, center-to-center, and the stabilizers were now half that distance behind them.
I continued to move the Image Stabilizers forward and found no improvement over the next foot or so. It appears that the sweet spot for them is a distance behind the speakers about half that of the speaker's distance apart—at least in my room.
I continued to listen to a lot of different recordings while moving the stabilizers in and out of position. I also experimented with the orientation and alignment of the stabilizers, which did not produce any benefits over simply stacking them facing directly forward. Regardless of the changes I made the Image Stabilizers continued to produce improvements to the sound when in place. And these improvements continued to be fairly subtle. This subtlety concerned me and led to a basic question in regard to what I was doing.
Was using the MG1.6s a good idea? They are dipoles and do not have the same sort of sound radiation pattern as a front firing box speaker (such as was used at RMAF). In theory, at least, dipoles have no sound emanating from their sides. Perhaps listening to a more conventional box speaker would result in sonic improvements similar to those that I had heard at RMAF.
I set up the FritzSpeakers Carbon 7 Monitors that I had reviewed in PFO Issue 50. These are very good sounding speakers with a wide frequency range and excellent soundstaging.
I again listened to a variety of music while moving the stabilizers in and out of the system and again heard the same sort of positive results that I had heard with the Magneplanars and to about the same degree.
As a result of all this listening, I concluded that the position of the Image Stabilizers in the room is what matters, not the type of speaker in use. As to the subtly of the changes I was hearing, they were what they were. I have spent a lot of time doing painstaking setup and adjustment; I would expect my room and system to perform better than a typical hotel suite.
The Group Listens
While I am perfectly comfortable writing about what I hear, I am never averse to having some other ears involved in the process.
As it happened, I had some members of the Gateway Audio Society coming over to hear my system. This was the perfect opportunity to get some additional feedback—they aren't shy about expressing their opinions—as to how the Image Stabilizers were affecting the sound of my room.
The GAS members all have very good systems and are experienced listeners. I got to play Ian Grant and move the Image Stabilizers in and out of the system as they listened. The Magneplanar 1.6s were back in the system at this point.
I was somewhat surprised by how unanimous their opinions were (knowing this group). There was complete agreement that the stabilizers in the system were improving the sound. These listeners used “more focused” almost universally when describing what they heard. Other comments noted that the sound seemed richer and more three dimensional. There was a minor dissent on one track where a listener felt that the improved focus traded off against a slight chestiness from the male vocalist. This was, however, only on one of the tracks to which we did comparison listening. All of the other listening we did during the day was with the Image Stabilizers in place. This never elicited any negative comments.
The GAS members also contributed a number of suggestions for experimentation with the stabilizers that time simply has not permitted pursuing. Among the suggestions was using them in corners, front and back of the room; at the point of first reflection on the walls; and even behind the listening position. We did try them, briefly, oriented horizontally between the speakers, an arrangement that I would not recommend.
It was gratifying to hear my own descriptions of the sound of the Image Stabilizes repeated almost verbatim by people whose ears I respect.
The Grant Fidelity Image Stabilizers never failed to make a positive contribution to the focus and overall soundstaging of my system. They also look attractive and impart an impression of professionalism in both their design and construction.
My own listening has left me of the opinion that how much of an improvement they provide will be dependent upon how good the acoustics of a listening room already are. The more difficult the room acoustics; the potentially greater the benefits.
Having gotten used to what they do for the sound of my system, I am not going to give them up. With some patience and experimentation, I think every listener will find a place in their room where these components will improve the overall sound whether used as stabilizers or diffusers. In fact, I am giving serious consideration to getting a second pair and hearing what additional benefits they can bring to my set up. Per dollar, they are stunningly effective for an audiophile accessory.
Absolutely recommended. Kent Johnson
I received an email from Ian Grant of Grant Fidelity after this article was published gently suggesting that I really should listen with the stabilizers against the front wall of my listening room. This is the position in which they were designed to be located. I had only gotten them within about 16 inches of my front wall due to the presence of my AC and speaker cables.
I did some rearranging and got the stabilizers against the wall, centered between my speakers. I listened to them in that position, in the position that I had settled upon, and with them out of the system. The stabilizers worked very well against the wall but I still felt there was a very nominal improvement in image focus where I had located them—a distance behind the speakers about half that of the speakers' distance apart. Both positions were clear improvements over no stabilizers at all.
I am not trying to be obstinate here and I am most definitely no expert on room acoustics. This is where they sounded best to me, in my room. I should point out that I have the luxury of placing my Magneplanar MG1.6 speakers just over seven feet from the front wall—a pretty substantial distance out into the room. Ian was concerned that my positioning of the Image Stabilizers was allowing sound waves to pass behind the stabilizers rendering them ineffective. I am wondering if, at the wall, the waves may be passing in front of them?
Definitely, the starting point for setting up the Image Stabilizers is against the wall, centered between your speakers. Listen to them in that position long enough to get a good feel for the improvement that they make. Then, if you feel like it, move them forward to any other positions that seem worth trying. The right position is the one where the central image is best focused and has the most body.
I am certainly not done experimenting with these components. If I find other positions/uses in which they offer worthwhile sonic improvements, I will pass that information along. Call me psychic but I think you will see GF's Image Stabilizers all over RMAF this fall.