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Positive Feedback ISSUE 30
march/april 2007


We sent out the same 20 questions to 50 manufacturers, the following are their responses. The intent of the survey is to address basic questions as to design along with any questions raging on various sites, while minimizing potential chest-thumping and friendly, or unfriendly, bashing of others....

Click here to read the other interviews in the series.


Darren Hovsepian and Terry Rossen of D.H. Labs
by PFO

PFO Why do cables make a difference? Interconnects, speaker, and AC cords?

Darren Hovsepian and Terry Rossen Anything in the signal path will make a difference, some not as much and some more to various degrees. An excellently designed and made, quality power cord will impact the sound of the music just as much as interconnects and speaker cables.

PFO What about metals ....copper versus silver versus gold versus what? What about blends?

DH/TR How the materials are processed is actually more important than which materials are used. The drawing and annealing processes have a major affect on conductor performance.

Non-ideal conductors can sound different from how the music actually sounded during in the Recording session or how the composer and artists thought it should sound. The differences can be additive or subtractive to the musical neutrality. Our cables are neutral and recording studios love our cables because they do not change the signal.

PFO What about dielectrics... Teflon versus what?

DH/TR From an electrical standpoint, a vacuum is the ideal dielectric for an audio cable. Air is virtually equal to a vacuum in this respect.  Of the polymers commonly used, Teflon is widely regarded as the best, due to its excellent electrical properties. However, the dielectrics used in audio cables also have physical properties that affect the performance of a cable. This is often overlooked, and it can have a major effect on the performance of shielded, low-level cables in particular. It also explains why some cables with good dielectrics (such as Teflon) often don't sound as good as they should. DH Labs actually uses different types of Teflon, depending on the cable.

Many years ago, DH Labs developed an exclusive dielectric that we call Air-Teflon Matrix. This is actually a honeycomb of PTFE (Teflon) and air. In addition to having dielectric properties that are far superior to solid Teflon, this material also has physical properties that were optimized for interconnect cables.

PFO What about no dielectric?

DH/TR Dielectrics insulate one conductor from another. Therefore some type of insulator is always required. The DH labs Air Matrix™ dielectric is about as close as you can get to no dielectric at all, because it is composed of 60% air.

PFO What about measurements... what do they tell us? What do they not tell us?

DH/TR Measurements can be very useful for digital cables, and can correlate very well with listening tests. Devising meaningful measurements for analog is more difficult.

PFO What about connectors... how important?

DH/TR We feel that the metallurgy of connectors is very important. However, the industry is only starting to recognize this. DH Labs has been making RCA plugs from pure, or nearly pure, copper for many years. In contrast, more than 99% of RCA plugs are still made from brass. It is an unfortunate truth that most cable “manufacturers” have no idea what alloys are used in their connectors, let alone anything about the plating.

PFO Why this geometry... ribbon, twisted, braded, spiraled...?

DH/TR The best geometry depends on the type of signal and the impedance of the circuit. Speaker cables operate in a very different environment from interconnect cables. Therefore there is no single best geometry.

PFO What about Cryo? What is going on with this?

DH/TR There does seem to be something to this. We believe it has to do with stress relief in the conductors. Unlike alloys (especially ferrous alloys), the fundamental crystal structure of a pure metals like copper and silver is not altered due to the application of cryogenic temperatures.

PFO Why shielding? Why not shielding?

DH/TR Shielding is only effective on certain types of noise. Noise caused by a magnetic field will pass through the shields on most cables, so the geometry of the inner conductors is still critical to overall noise rejection. Shielding can also increase the capacitance of a cable, so it has to be applied properly.

PFO What about run-in.

DH/TR This is mainly a phenomenon where, after signal has been applied for a certain amount of time, the (polar) molecules of the dielectric are able to align with the electric field of the audio signal more easily.

PFO How did you get into this?

DH/TR Back in his early years of college in the 80's, the founder of the rapidly growing D. H. Labs, Darren Hovsepian (The D.H. of D.H. Labs) began to create his own microphone cables by hand. He had recognized when changing the microphone cable when recording college choral groups, jazz ensembles and the college orchestra that the microphone cables where changing the way the recording sounded.

Darren listened to each feed with a different cable but same microphone; there was an immediate difference in the way the music had been recorded. As he was studying Electrical Engineering, he thought to himself that the changes in the sound were apt to be a different in the microphone's resistance and capacitance. He measured the differences and although the readings were similar between the two test cables, the actual sound was different.

He had determined during the comparison testing that the actual dielectric in the cables had an unmistakable effect on the quality of the sound. This conflicted with a previous notion from his Electrical Engineering studies that the cables dielectric should not have made a major effect on signal at audio frequencies. His ears showed him that the books were wrong. The testing led to the creation of several microphone cables that were amazingly open, clear, and true to real life from the recordings.

Darren continued to make his hand made cables for his own use until several others started asking him to make cables for their recording rigs and their stereo systems. All of his cables back then were entirely made by hand, an extremely tedious process which made selling the cables at a reasonable price near impossible. There had to be a better way. He wanted his designs to offer performance and affordability, the cornerstone of his current success. He researched manufacturing his exact designs for audio and video cables. All his lengthy research did pay off when an American manufacturing facility under contract with NASA offered the ability to put DH Labs Silver Sonic High Performance Audio and Video cables into production.

Many competing cable manufacturers were using oxygen-free copper at the time. Darren had also found that during the testing that North American conductor material made a difference in sound as opposed to material that is sourced from Asia. He began to experiment with ways of combining silver and copper as a conductor. Many people had thought that because silver is a better conductor that it naturally should be better in a cable design. But the surface of a silver conductor is also less damaged by the drawing or extrusion process, because silver is softer than copper.

Darren consulted with metallurgists for a method to achieve a mirror smooth surface to his conductors, which goes a long way toward preserving the minute low level acoustic detail which is most important in the recording of music. But pure silver conductors were very expensive. He found a solution to that expense by discovering a way that combined pure silver on the exterior and used a pure copper interior conductor. The ultra-smooth silver would be excellent in preserving the low-level detail in a recording, and the combination of silver and copper would allow the detail to be preserved along with the preservation of the pure copper. The perfect mirror surface could be drawn thin enough to his measurements over the pure copper conductor and be done in such a way to prevent the pure copper from ever oxidizing. Silver is largely immune from the degrading effects of oxidation that had been the plague of copper conductors. Using silver also increases the electrical conductivity of the conductor, and this conductor could be produced at a very reasonable cost for the consumer.

Hovsepian also found that if you can control the quality of materials close to home you can create virtually perfect cables and still maintain a reasonable cost. This is very rare in the cable industry. DH Labs sources virtually all of its materials from North America, while most other cable companies are outsourcing their complete product line from Asia to maximize profit margins.

D. H. Labs has many products today that use proprietary materials developed by Darren with the help of outside engineering and metallurgy companies. Darren invented a proprietary new Air-Teflon™ Matrix dielectric material for his cables that is actually 65% air which is a great improvement over pure Teflon. The higher amount of air in his Matrix approaches that of the dielectric constant of 1.4 which is a perfect vacuum, the ideal dielectric.

Darren worked two years on his High Copper Alloy metal which is utilized on D. H. Labs connectors. Most connectors in the cable industry are using brass or bronze. These are poor conductors since they are only 25% as conductive as copper. With the help of several metallurgists, D. H. Labs developed the HC Alloy which is 99.5% pure copper and .5 % other metals added as hardeners for strength and durability. The conductivity of the HC Alloy is 93% and almost 5 times that of a typical brass connector!

PFO What is your fundamental design philosophy/goal?

DH/TR To produce a neutral cable design that does not impart its own signature on the music signal.

PFO Why these?

DH/TR To allow the listener an open window to what the composer intended the music to sound. 

PFO How successful do you feel you have been at achieving the goals that you have set for yourself?

DH/TR We have been in business for over 15 years, without the need of a huge advertising budget. Word of mouth brings most of our customers to us. By not spending huge amounts of our budget on advertising, we pass the savings directly to our customers. This allows us to use the finest materials available/obtainable in North America in our cable designs. Our cables utilize the same or higher quality materials found in cables that cost 5 to 10 times more. Our cables are one of the absolute audio bargains in the world.

PFO How do you plan to push beyond what you have already accomplished?

DH/TR We are constantly designing new products that our customers will utilize now and into the future.

PFO Where is this all heading?

DH/TR DH Labs will continue with the best engineering, obtaining the finest materials, offering the most natural sound which allows the music to be heard as the artist wanted it to be heard. DH Labs offers cables that are true to the music without being stratospherically priced as other manufacturers. Our cables are listened to savvy music lovers and have become an ultimate high-end cable choice and recognized as the sonic bargain of the 21st Century.

We will continue developing and offering our cables and wire that allows the finest performance obtainable regardless of our customer's budget.

PFO Others that you admire?

DH/TR I have always admired Leonard Bernstein and his Young People's Concerts. As a youth I attended his live concerts at DAR Constitution Hall in Washington, DC. He provided me with my earliest appreciation and understanding of music.

Click here to read the other interviews in the series.