A Reality Check Article
Hsu Research HRSW10V Subwoofer:
More bass, more music
A Reality Check Article
Hsu Research HRSW10V Subwoofer:
More bass, more music
My need for subs was forced upon me when I was trying to sell the Sound Lab A-2X electrostatic speakers to someone more willing than I to invest further in the system. I wanted to move on to other things. See the review of the Sound Lab A-2X speakers in a previous issue. Not surprisingly, three initially very interested individuals were discouraged by the sound of these speakers. The last prospect, who owns double Quad ESL's (the original 57's in stacked pairs) with a Janis subwoofer for each side, had originally visited to find out whether the A-2X could stand on its own merit as a full range speaker. He had hoped to downsize. His hopes were quickly extinguished. The Sound Lab A-2X sounded horrible I must admit. Three individuals echoing my exact sentiments provide corroboration. But the third individual also left me with some pearls of wisdom. One of his parting suggestions was that I get at a subwoofer to realize the true bounty of the A-2X. With this in mind, I turned to subwoofers.
Discovery
My first stop was to look at reviews from my stockpile of magazines. I also consulted Sound Lab. The Muse subwoofers were highly regarded by the press. Sound Lab mentioned them as well. The trouble is the Muse subs are very expensive. Unable to justify such an extravagance on an untested set up, I looked at other alternatives and finally obtained for a 30-day home trial a Velodyne VA1512 with a 12" active front firing woofer, a 15" down firing radiator, and 250wpc internal amp.
Several years ago I attended the Stereophile HiFi show in San Francisco, and was impressed by the Hsu Research subwoofer. For your information, Hsu subwoofers are only available direct from the manufacturer (ph. 800/554-0150). After several telephone conversations and faxes, I acquired a Hsu Research HRSW10V, a compact and more economical alternative to the tried and tested HRSW12V that has been favorably reviewed by many audio publications. I ordered the subwoofer with the 250w amp option. My choice was prompted by two reasons--cost and domestic harmony. The 10V is approximately $200 less than the 12V. It is also smaller, hence less obtrusive. Considering the other furniture in the family room which is where I have stationed the Sound Lab speakers, I thought that this would be more aesthetically fitting. Harmony at home has a higher priority to me than audio.
Description
As the least expensive subwoofer in the Hsu line, the HRSW10V uses a 10" woofer and comes only in one finish--with the Zolatone granite top and black grill cloth. You have three options in purchasing a subwoofer from Hsu Research. You can buy the subwoofer by itself sans the Hsu external amp, with their 150w amp or 250w amp option. For your information, their amps come with an equalization function to enable the sub to reach down to 25 Hz. Hence, while you may be able to save by using an extra 150w amp that you may have lying around your house, the caveat is with your amp the HRSW10V will not go as low as specified. It was stated that the lower limit would then be around 30 Hz.
The HRSW10V subwoofer is housed in a cylindrical enclosure measuring 18.5 inches in diameter and 17 inches in height with the black anodized aluminum spiked feet attached. The subwoofer weighs 30 lb., the amp which is a separate unit is 13 lb. The standard crossover frequency is 91 Hz, with optional frequencies set by plug-in modules for the following frequencies: 28, 34, 34, 51, 62, 75, 108, 131, 155 Hz. For fidelity, a fixed frequency approach is superior since it eschews signal deterioration that would have resulted from the use of a potentiometer. The following controls are provided along with the amp: subwoofer volume level, phase (0, 180 degrees), crossover (in/out), and soft-clipping. There are also provisions for line and speaker level (full-range signal) inputs and one line level (high pass signal) output.
Connections
The preferred manner of connection is full biamplification. In this mode, bass frequencies are excluded from the main speakers, relieving them and the main amp from the hardship of handling the lower frequency range. It is this freedom from stress that provides the potential for the subwoofer and amp/crossover system to elevate the performance of the main speakers and bring these to an altogether higher level.
Biamping requires that your system have preamp outputs and main amp inputs. For separate pre and power amps, this is given. Integrated amps or receivers must have pre-out and main-in jacks.
The HRSW10V can also be connected for bass augmentation. For receivers and integrated amps that do not have a pre-out or a main-in, the subwoofer can be fed speaker-level signals. The subwoofer's amp, with its controls, has the built in flexibility to accommodate the use low pass and THX outputs. All of these modes of connection are succinctly explained in the instruction manual.
Reference equipment
The following components were used to evaluate the HRSW10V: Audible Illusions Modulus 3 tube preamplifier, Classe' DR-9 amp, JVC XL-Z1050 compact disk player, Inouye Line Conditioner, Promethean Bandpass Interconnect, Linn Sondek LP12 turntable with Valhalla, Linn Ittok LVII tonearm and Linn K18 cartridge, and Kimber 8TC speaker cable. I had the system playing for about two hours before reviewing the subs.
How does a sub sound?
Not much. It just goes bam-bum-um-umm and so forth. Pretty uninspiring really. Some might question a subwoofer's functional value given its limited range of frequency output. The Velodyne sounded the same and slightly tighter. I suspect this is because of its front firing woofer. Nevertheless, I opted to return it and stay with the Hsu HRSW10v for two reasons: (1) I had surmised that the Hsu uses a better quality speaker and (2) its provision of a separate amp/controller unit. With the Hsu, you only need one set of wires to the sub. You can co-locate the main and subwoofer amp, and use use short interconnects. I don't think that it's a good idea to have a lot of long wires (power cord, interconnects in and out, and speaker cables) snaking along with the sub. There are complications that are not readily apparent --the additional cost for longer interconnects and cables, signal degradation, placement limitation, and possible hazard of having all these wires in someone's path.
How did the HRSW10V perform?
Famously, to my relieved ears. It did take some time, patience and several tweaking sessions to determine the right volume level and position for the subwoofer. To my surprise, the 10V despite its relatively small size is able to produce solid, articulate, and extended bass--bass that can be viscerally felt on appropriately recorded material. To my even greater surprise, it integrated splendidly with the Sound Lab A-2X. I have often heard that electrostatics are both finnicky and more difficult to match with subs because of their speed. It must be my lucky day!
I realize that placement has a large bearing on integration. So for starters, I followed the recommendations outlined in the instruction manual. In the end, I found the arrangement where the subwoofer is right in the middle of the two A-2X speakers with myself about eight to ten feet in front of the subwoofer as the ideal position. The Sound Lab A-2X's require breathing space to really sing so this may not be the ideal positioning for your system. Take the time to fit the subwoofer to your main speaker and your environment.
A friend of ours who had helped me pick up the A-2X at the Dallas/Fort Worth airport when they first arrived from California, happened to drop by for a neighborly chat. He was amazed at the metamorphosis brought about by the addition of the HRSW10V. Here is canvas of sound that even I could not have envisioned possible from a small cylindrical enclosure and a set of electrostats that I had nearly given up on as a lost cause. From such ignominy, here I now feast hour upon hour with a stream of LPs that were previously hideous with the A-2X. It was a real awakening, an epiphany if you will. The Sound Lab A-2X has a plethora of musical talents after all. Oh what a difference a sub makes. What a difference the HRSW10V makes.
Conclusion
The individual who had originally sent me on the path toward the utility of subwoofers had a second part to his suggestion. He averred that a second subwoofer, a stereo arrangement, will provide an additional 30% sonic improvement. Frankly, I am at this point satisfied with the use of a single HRSW10V. Not having tried a pair, I cannot however criticize or confirm the wisdom of his assertion. Given the relatively small investment required to obtain this incremental performance and the small footprint of the HRSW10V, I am tempted to spring for another one. Thanks Hsu Research for coming up with this sonic bargain ($800 retail for sub and 250w amp). Highly recommended.
by Rome Castellanes
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