Velodyne Feedback
Dear Gary: We thank Mr. Hardesty for his review on the Velodyne HGS-12. After having read the review, I believe that your readers may be interested in hearing another view about the product in question. Some of the issues raised in the review leave some room for discussion. To that end, I would ask you to include the following remarks in your next edition. Mr. Hardesty has been in the audio industry for many years, and I have the utmost respect for him. I first met Mr. Hardesty in the spring of 1983 when I demonstrated one of the first CD players available in the USA for him. At that time he was the co-owner of a retail store called Havens & Hardesty located in Huntington Beach, California. However, regardless of the respect I have for Mr. Hardesty, I feel obligated to make a few remarks about his review of the Velodyne HGS-12. It is clear Mr. Hardesty is skeptical of the Velodyne High Gain Servo control system. Since its introduction in 1984, reviewers the world over, who have experienced the quality of out High Gain Servo controlled bass have been impressed. Here are a few samples of the comments made about the servo controlled subwoofer’s performance: “I’d rank the quality if not the magnitude of the small California Company’s achievement up there with Dolby noise reduction and the compact disc.” (Audio Magazine, November 1987) “For once an add-on subwoofer actually delivers true subwoofer bass with high quality and high quantity at the same time.” (Stereophile, October 1989) “As any audio buff would tell you, the name Velodyne is synonymous with high performance subwoofers.” (Audio Video Interiors, August 1994) “The bass was also clean and tight, avoiding the loose bloated quality people dislike about subwoofers. (Stereophile, October 1995) HGS-12 dB Keele “On the basis of it’s output alone, I’d rank the Velodyne HGS-12 in the top half of all the subwoofers I have ever tested, but it’s low distortion places it at or near the top of my list.” (Audio, June 1998) As you can see for the past 10 years, Velodyne subwoofers have been recognized as the best available by reviewers, retailers, and most of all, our customers. We are the benchmark by which all other subwoofers are measured. In his review, Mr. Hardesty makes a mention of the fact that our voice coil may in fact be out of the gap with our 1.25-inch excursion. In point of fact, our voice coils don’t go out of the gap because we use a dual tandem drive voice coil that is three inches wide and six inches long. It has mechanical peak to peak excursion of two-plus inches when outside of the box. However, the driver is limited to about 1.25-inches in the box because of the size of the cabinet. The dual-tandem windings of the voice coil are wired out-of-phase with each other, and in conjunction with the dual spiders, ensure the most linear motion. Our driver is built by us, in house, to very high standards. It is hardly an off-the-shelf OEM woofer, like many other subwoofer manufacturers use. We developed the machine that winds the voice coils and it is proprietary to Velodyne, and the only one of its kind in the industry. I would suggest that if Mr. Hardesty had a better understanding of the way our dual voice coil and servo control system operate, he might recognize its clear advantage. Our bass performance is acknowledged as being extremely deep, tight and accurate. Clearly his comments about pitch definition are without basis since it is in this area that the low distortion design, that we have pioneered, excels. Later in the same review, Mr. Hardesty, mentioned that the woofer sounded a little “slow.” This remark is an “oxymoron!” The speed of sound is fixed and is only effected by variations in moisture or altitude. For any given frequency the wavelength is also fixed. The only variable therefore would be the amplitude and time/phase. Typically the wavelengths of bass frequencies are extremely long and time/phase is hardly an issue. Our experience with servo-controlled subwoofers indicates that most of the problems Mr. Hardesty experienced, while trying to achieve a satisfactory blend, can be traced to placement issues or the setting of the low pass crossover to match the speakers concerned. Indeed our subwoofers have been satisfactorily matched with every brand of loudspeaker from Apogee to Wilson and anything between. The awareness of a subwoofer in the room, as Mr. Hardesty mentions in his review, can also be attributed to room placement problems. Many people think that bass is non-directional so you can place a sub anywhere you like in a room. That is a common misperception. In fact, proper placement of a subwoofer can dramatically improve or detract from the overall system performance. Nodes and cancellations, defined by room dimensions play an important role in the overall performance as well. Many writers, engineers and designers have written extensively on these issues so I will not go into them here. Suffice to say that when you have been making subwoofers for as long as we have, you are painfully aware of the placement issues. We thank you once again for the review and respectfully recommend that you consider our commentary. Thanks for your interest in Velodyne. PS. I would refer you to an article written by John Atkins (Contributing Technical Editor of Stereophile Magazine). His article on speaker design was published in the December 1998 edition of the magazine. The remark “oxymoron” was his, not mine.
Geoffrey Marks, Velodyne Acoustics, San Jose, California
Editor Gary Reber Comments:
Richard Hardesty has reviewed more subwoofers than all the writers put together that you credit. I trust Dick’s performance judgment implicitly. As a matter of fact, all the subwoofers reviewed thus far in this Widescreen Review series have been evaluated using the same equipment and room setting, and have been reviewed based on comparative experience listening to each sub. I asked Dick to respond to your letter. Audio Review Editor Richard Hardesty Comments: Readers who have followed my subwoofer series in Widescreen Review already know that I am aware of the speed of sound and I can calculate wavelengths at any frequency, so I won’t belabor those points. I have written extensively about room placement problems and how to overcome them, and I have discussed the design compromises that might result in a subwoofer that sounds like it lags behind the main speakers (often described as one that can’t keep the beat, or simply “slow”) or one that produces bass that sounds disconnected from the rest of the spectrum. Bragging about the length and girth of your voice coil former is irrelevant, and advertising a maximum excursion dimension that cannot be achieved is misleading. The only dimensions that matter are the length of the voice coil windings and the width of the magnetic gap, which are expressed (we hope accurately) in the specification for linear travel. That’s what I was trying to get across in the review. I have installed, adjusted and repaired (down to the component level) a number of Velodyne subwoofers over the years. I am completely familiar with the various types of servo control mechanisms (dating back to the early Infinity designs), and I am completely familiar with the dual-motor, push-pull voice coil concept,—the first examples of which appeared in some Vandersteen models as early as 1985. I fully understand the engineering that produced the HGS-12. I find it impressive and I said so in the review. It’s the sound that I didn’t like. This Velodyne subwoofer performs very well in many ways. It will play explosions and other sound effects with the best of them, as I stated in the review. I believe that there is a lot more to good bass than “loud and low” and I listened to music through all the subwoofers in the review as well. In my opinion, the HGS-12 is just an average performer when reproducing music, and at $2,000 retail I couldn’t recommend it. Here is my advice to our readers: While I don’t find the Velodyne subwoofers appealing for my own use, one of their models might be perfect for you. These reviews express my opinion. When it comes to your living room, your opinion is far more important than mine. You need to listen and decide for yourselves. I’ll tell you about two of the many methods that I used to evaluated the subwoofers in the review, and you can try these and see if you come to the same conclusions that I did. Then devise your own listening protocol for further exploration. Get a copy of Doug Macleod’s CD Come To Find from AudioQuest Music (or another disc that contains up-tempo, rhythmic musical selections) to take to dealer showrooms. Listen to cut #10, “Rollin’ & Tumblin” using a properly set-up M&K MX-700 powered subwoofer (or another model that received high marks for Rhythm and Pace). Now play this same cut using the Velodyne HGS-12 subwoofer. To my ears, after switching to the Velodyne subwoofer, the music sounded like it was being played at a slower pace and the individual musicians seemed to have lost much of their sense of rhythm. You may disagree. For those of you with computer-based test instruments, try this: using a sinusoidal tone-burst at about 30Hz as a stimulus to the HGS-12, compare the amplitude of the first cycle of output to the amplitude of those that follow. Draw your own conclusions.
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