K&B Signal Solutions Concert Series Introduction

K&B Signal Solutions is a newcomer to the audio industry. A group of Mechanical Engineers set out to produce affordable and well performing cable products, snake oil free. One unique perspective they bring to the table is their very clever and practical terminations comprised in their new speaker cable known as the Concert Series . I know you have heard this before, what could possibly be unique or differentiate this company from the next cable company? It's called "Interconnection Modularity". This allows the end user to swap out cable terminations or add extenders to increase cable length without any needs for crimping or soldering. It is basically a "tool-less" design involving pressure applied by the end user to make the connections and terminations.

The Concert Series cable comes fitted with banana plugs which interfaced quite well with my Status Acoustics Decimo's . It has always been a challenge to say the least to find non compression style banana plugs that fit snugly on these speakers. The nice thing about this cable, is if the banana plug doesn't fully insert into the binding post, you can pull the PVC rubberized sleeving over the connector to make it fully flush.

K&B; Concert Series Design

The Concert Series cable is a basic 12 gauge twin feeder cable (or more popularly known as " Zip Cord "). However its cosmetics are dressed up via a slick wine color nylon sheath with a slidable strain relief PVC insulator to encase the terminated cable and ensure no metal contact area is exposed once fully pulled over the terminations. The terminations are gold plated brass alloy construction. The default base terminations are banana plugs which are soldered snugly to the cable.

Your cable termination choices are as follows:

• Banana Plugs (default) - used for pushing into back of binding posts of most amps and speakers.
• Splice Cable Connection - for seamlessly adding cable lengths via daisy chaining.
• Positive and Negative Fastons - popular when interfacing with raw speaker drivers.
• Flexible Pin Connector - similar to a gold coated wire which is easy to pass through a speaker's binding post before tightening down much like you would do with bare wire only there is no strand fraying to deal with since it is coated and self contained.
• Spade/Fork Terminations - popularized by many esoteric audiophiles though in my opinion usually more problematic then beneficial. In this case, the furnished Spade connector was not wide enough to accommodate any of the speakers I had on hand for review. I would have preferred an offering of different sized spade connectors or one adjustable one.

Editorial Note
Regarding Faston Connectors: The most common Faston size is .205". Many loudspeaker drivers, (IE. American, Chinese or European-made) also are spec'ed with .110 for the negative terminal. The American design engineers do this so that the assembly line workers can't mess up the polarity changes, if any, that are inherent on their specific design.

Regarding Spade Connectors: This spade- connector-too-small-to-go-around-the-threaded-terminal-shaft is an almost universal problem. Many of the Chinese-made terminals have threaded shafts large enough so that a hole, large enough to accept a banana terminal, can be drilled through the shaft. This allows the consumer to have banana plug wires and still crank them down much more securely than would be the case with just sticking them in the end of the terminal. According to K & B Signal Solutions, the original intent of this connector was to interface with car amplifiers.

K&B; Concert Series Measurements and Conclusion

The banana terminations are soldered onto the cable firmly as indicated by a rugged pull test we conducted.

Pictured above illustrates the Splice termination connecting two 12" Concert Series cable lengths and pulling the sliding sleeving over the connection to add stiffness and eliminate any conductor contact exposure to the outside world.

For the most part terminating the cable in this fashion was simple, though sometimes it was difficult to pull the default banana plug cable out of the sleeving after unterminating the cable. The workaround is to insert one of the Splice terminations to the banana termination and pull while holding onto the slidable strain relief.

I found the Splice termination to be particularly useful in situations where cable lengths need to be increased because of speaker repositioning or moving the gear to a different location. Rather than throwing away an existing cable, one can simply purchase an additional length and salvage the cables they purchased prior. I know what some of you may be thinking. Daisy chaining cables like this can degrade sound, especially if contact resistance is increased in the process. Rest assured however that this was not the case for this solution as our measurements revealed.

Measurements and Analysis

Using our Wayne Kerr 6420 Impedance Analyzer which graces our Test Equipment Laboratory , I measured all of the critical metrics which directly affect cable performance. The DC resistance of my first 12" cable length measured to be Rdc1 = 43.3 milliohms, while the second 12" cable length measured to be Rdc2 = 43.5 milliohms. If no added contact resistance is present by interfacing these two cables, then the total added cable length for the equivalent 24" cable should be Rdc1 + Rdc2 = 43.3 milliohms + 43.5 milliohms = 86.8 milliohms.

When I connected the two 12" cable lengths together via the Splice connection, I measured an equivalent DC cable resistance Rdceq = 85.3 milliohms which was 1.5 milliohms less than the sum of the two cables. Obviously this cannot be correct, unless the connectors exhibited superconductivity behavior (watch for some exotic cable vendor pushing this in the future ;) ).

What this did indicate however is that the Splice connectors were NOT adding any measurable contact resistance. The reason the daisy chained cable measured lower DC resistance than the sum of the two has to do with the precision of the milliohm meter internal to the Wayne Kerr Analyzer. The longer the cable length measured, the more accurate the measurement is since you are operating in a higher region of linearity of the test equipment.

Cable Metric Definitions

Cable Measurement Test Set-Up Notes

All of the above measurements were completed on a fully calibrated and certified, Wayne Kerr 6420 Impedance Analyzer . The 6420 was calibrated for full frequency bandwidths and for greater accuracy the measurements and calibration process was repeated twice for consistency.

All cable lengths measured were 12 feet and divided by their length for a normalized per foot measurement. At low frequencies the results illustrate Rs being lower than Rdc, which is inaccurate, as Rs tends towards Rdc as frequency approaches zero or DC. The LCR measurement derives Rs from signal phase and amplitude, while a DC meter measures exactly what it is looking for, thus this discrepancy is likely due to a meter resolution issue, as the meter in AC mode does not sport the high accuracy it would in DC mode. The cable should ideally be modeled as multiple parallel resistors, and those resistors treated as a lumped element in series with an ideal inductor.

Each resistor is a frequency dependent element, and the inner ones fall out as the frequency increases. It is important to note the difference in measuring techniques, and caution the reader not to attempt to derive any relationships with the two numbers, as the absolute accuracy between the methods has not been established. However, the rising trend of Rs vs frequency is indicative of increased Rac due to skin effect and should also be noted.

Inductance measured similarly to 12AWG Monster cables from Speaker Cable Face Off I . We see a minimization of internal inductance due to skin effect at frequencies above 20kHz. While this is measurable, it is not something that cannot be sonically detected in real world audio application nor is it cause for alarm since just about every speaker cable we measured, regardless of their price, appearance, or claim to fame for resolving skin effect exhibits similar behavior.

For a more detailed discussion on cable inductance, the reader is encouraged to review our article on Calculating Cable Inductance

The resistance of the K & B Signal Solutions Concert Series cable is about 12AWG at DC.

We see a rising AC resistance with frequency of about 20% and 20 kHz, again attributed to skin effect, but practically speaking a non issue for the application of high fidelity audio.

For a more detailed discussion on Skin Effect, see our article on Skin Effect Relevance in Speaker Cables

Capacitance about on par with 12AWG Monster Cable from Speaker Cable Face Off I . We see the capacitance decrease with frequency for two reasons, slight instrumentation error of measuring a distributed device (speaker cable) with a measurement tool designed to measure lumped elements (magnetics, electrical circuits, etc), and a decreasing dielectric constant with frequency. While many esoteric cable vendors and cable cult hobbyists would have you believe this is considered Dielectric Absorption and will again cause audible distress, the reality is most cables exhibit this behavior and it is not something that will cause deleterious effects on fidelity or performance of even the most demanding and revealing audio systems.

For more information on Dielectric Absorption, see our article entitled Debunking the Myth of Dielectric Absorption

Recommendations

If you are looking for me to describe a spiritual experience I had using these cables, you are reading the wrong publication. I only hear differences in cables that are poorly designed, and subsequently have poor corresponding measurements. The Concert Series cable from K & B Signal Solutions is not such a cable. If you are looking for an affordable cable comparable to a good quality 12AWG Zip Cord popularized by Monster Cable and other well known cable vendors, but with nicer cosmetics and the inclusion of a variety of terminations all of which can be implemented tool-lessly, than this may be the cable for you. If you envision yourself repositioning speakers and/or electronics in the future and desire to re-use your cables by simply adding more cable lengths by daisy chaining them via the Splice termination, than this is one cool feature you must have and one unique to the K & B Signal Solutions Concert Series speaker cables. In a world of cable hyperbole and nonsense, the K & B Signal Solution makes sense.

K & B Signal Solutions Concert Series Speaker Cables
MSRP: $80 for a 12" pair with terminations
http://www.knbsignalsolutions.com/

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Performance
Value