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Wednesday
Feb 18 2015

Several Hundred Words About Timbre, Or, Did You Know the LS50 Is Also Available As A Center Channel?

One of the more elusive terms in the audio world (and in music in general) is the word timbre . First of all, if someone starts explaining TIM-bur to you and they are not speaking exclusively about a forest or a logging operation, run away and leap unabashedly into the arms of your nearest audio expert who knows the word is pronounced TAM-bra (it's a French word).

According to the Oxford Dictionary of the English Language:

  1. timbre
    [ ˈtambər, ˈtäNbrə ]
    NOUN
    noun: timbre · plural noun: timbres
      the character or quality of a musical sound or voice as distinct from its pitch and intensity

Three Things We Need To Concern Ourselves With When It Comes To Sound

  1. Pitch (the note being played, or how high or low the frequency of a sound is)
  2. Intensity (the volume of a sound)
  3. Timbre (the subject of this blog piece)

Let's Listen To Some Examples Of Pitch And Timbre

In the above video that I borrowed from the Internet, we can easily hear the differences in pitch within the two examples. The intensity (or volume) is constant. In the first example there are three synthesized flute notes, two have the same pitch and one has a different pitch, but all three examples display the same timbre.

In the second example, there are four different synthesized voice notes and there are some other subtle differences. All four have the same intensity, so we need not worry about volume. But if you listen to the character on the left, you can immediately tell that the character is female (as compared to the male constant we are comparing to). In this case, not only is the pitch different, but so is the timbre of the note. That difference in timbre is what allows our brains to process the auditory sensation as being distinctly female when compared to the male constant. When listening to the third choice as compared to the constant (the character on the right) it is easy to tell that the pitch is obviously different, but there is also a slight difference in timbre, which again allows our brains to process the note as being different from the constant.

What all of this means is that when listening to music, or any other audio program, our brains contrast and compare three things while processing what we are listening to: pitch, volume and timbre.

Now let's listen to some examples of different instruments playing the same note (pitch) with a graphic representation of the sound-waves created. By actually seeing this presented graphically it becomes clear what timbre is, and how important it is.

A couple of disclaimers: All of the notes here are re-produced electronically. What this means is that the natural instrument will have (typically) more detail, air (space) and quality within the frequencies created, but for our purposes this illustration is fine. Also, the use of this video in no way endorses the content on the original website of the producer of the video, but is used here strictly for educational purposes under Fair Use.

Here's the Point

The point is, we hear a lot of gobbledygook about timbre matching when it comes to speakers, and the simple fact of the matter is, timbre matching is extremely important.

As important as timbre is in distinguishing a violin playing an 'A' from a banjo playing the same 'A', your speakers need to be able to accurately and articulately make that same distinction when re-producing those notes. Equally important to that, if your speakers are not timbre matched, the violin in say, your left channel, will sound markedly (and annoyingly) different from the same exact violin playing in your right channel.

Certainly, you want to timbre match your front three speakers (Left, Center, Right) as closely as you can, and if you listen to a lot of music that is mixed to 5.1 (or higher), timbre matching the rear speakers is equally important. If you are going to use your system to listen mostly to movies, timbre matching the rears to the fronts is not as important, but you should definitely stay as close as possible to the timbre of the fronts.

That Means

Your front three should be the same brand and model (or series) speaker whenever possible, and your rears should match as much as is reasonable. You can certainly have a mis-matched pair of rear speakers (relative to the fronts, not to each other) and your movie watching will be acceptable, but you will absolutely notice the difference when you timbre match every speaker in the system.

From series to series, KEF speakers are timbre matched, ensuring amazing articulation from channel to channel. To up the ante a bit, we have also begun offering our LS50 in a single speaker package for use as a dedicated center channel, so now it's possible to have a 5.1 (or higher) system made up entirely of our incredibly popular LS50.

So, as you put together your dream home theater or music listening system, when deciding on your speakers, remember, timbre and accuracy are every bit as important as is power handling.

Jack Sharkey for KEF

Wednesday
Jul 16 2014

C Series: You Can Afford To Listen To Music That Sounds Great

This morning, while fighting with my updated Norton Internet Security subscription to get my Spotify account to stream, it occurred to me that the quest for good sound is more about the journey than it is about the final destination. I still listen on occasion to the same music I listened to in college and high school, and even though I can hear it all with far more clarity and definition than I could back then, my enjoyment of the music itself hasn't really changed all that much. The point is, for me, it's about the music and the technology just helps me get my fix.

A Short List of Things I Wanted When I Got Out of School

  • A Yacht
  • A Datsun 280Z or a Lincoln Mark IV (even though the Lincoln was kind of old by then)
  • A job in a recording studio in Manhattan
  • A girlfriend who didn't dig me just for my money
  • An outrageous stereo

Seriously, what could have been better than being a long-haired punk tooling around in one of these? This.

Here's What I Got

  • An afternoon on the Circle Line (you New Yorkers will get it)
  • A six year old Buick Century with no AC and a power steering leak
  • A job with a soulsucking computer company fixing things I knew nothing about and cared about even less
  • A girlfriend who not only didn't dig me for my money, she didn't dig me for any reason but stuck around for the money (what little of it there was) anyway
  • A turntable from JC Penney, a second hand receiver that needed a magnetic cartridge pre-amp and a pair of AR-18s

Yachting is a state of mind. Yeah but, the twenty-nine dollar 8-Track I bought at Pep Boys played my Clash tapes quite nicely.

Here's What Happened Eventually

  • I bought a canoe I hardly ever use
  • I wrecked the Buick (and my back) during an unfortunate incident involving ice and a telephone pole
  • I spent 12 years doing something I absolutely hated but got paid for, so what the hell?
  • I wised up about the girlfriend when I realized I was paying more for her Fashion Bug credit card balance than I was paying for my own albums and concert tickets
  • I used those little AR-18s through the New Romantic, New Wave, Synth Punk and Hair Metal phases of the 80s almost right into Grunge

( I'd show you a picture of the canoe sitting in my backyard on the stand I built for it, but then you might be able to use Google Earth to find out where I live )

Today, I have a very nice stereo system, thank you very much. To some people who hear it, it's amazing while to others it's fairly humble. No matter, because whether I'm listening to some scratchy old Brit Metal record or streaming Shabba Ranks from my XM/Sirius, it sounds great to me.

I've always considered myself a music lover more than an audio hobbyist, but my love of music wound up putting me on the same path as those guys who don't really like music all that much but who are totally caught up in the gadgets they play their Dark Side of the Moon albums on. I don't think one is better or worse than the other, but I do think a lot of people are turned off to enjoying really superior sound in their homes because they think they have to become audio geeks first – or they think they can't afford it.

My humble little 35W JVC receiver with the off-brand turntable and those little AR-18s served me well for a long, long time. But as my budget grew, my ability to listen to music that sounded great also grew. Notice I didn't say my "stereo grew" because it's never really been about the components to me. Today, I'm a pretty lucky music lover because I have access to some really superior product and I get to be around the best of the best on a regular basis, but I still have a kid in college and car payments and stuff that though I try to ignore, always seem to require my monthly attention. Just like pretty much everyone else.

But like beer, food and air, music is a life staple to me. Just like pretty much everyone else.

Here at KEF, we're known for our flagship speakers, The Reference and Blade , and our R and Q Series because of how fabulously they perform, but we also understand that not everyone (yours' truly amongst them) is in a position – or has the desire – to satiate their need for music with top of the line gear.

C Series. They're Not As Good As The Reference

Right, they'll also cost you $279.00 for a pair of bookshelf speakers. But that $279.00 pair of bookshelf speakers will absolutely amaze you with their ability to reproduce your music without breaking your bank. Seriously, I put virtually no effort in and I found a Yamaha receiver for $249.00 that would match perfectly with these speakers. You can start today by plugging your phone or computer into the receiver and for $528.00 you are actually going to be able to hear music that sounds really, really good floating around the air in your room – the way music was meant to be heard. I agree that music through headphones or earbuds is okay for some uses, but when's the last time you actually enjoyed listening to pre-recorded music in a room? And no, by pre-recorded I don't mean that [ Insert Name of Corp Pop Ingenue Here ] concert you went to last week. By the way people, please stop listening to music on the speakers that come with your computer, it's ruining your life. Normally, I would write a spiffy little paragraph about our awesome X-Series Digital Computer Speakers right now, but that's not what this piece is about, so let's just move on.

The C-Series doesn't have KEF's famed Uni-Q , but let's be real here for a second, not buying a system because you can't afford the best is like walking because you refuse to buy the car you could afford instead of the BMW you want. With technology the way it is today, you can get yourself a great entry-level system at a price you can afford, so start your music-loving journey sooner rather than later and see where it takes you.

Sure, KEF has built its reputation as the high-end leader in the loudspeaker industry, but we did it one step at a time – just like anything else of quality, it takes a lot of steps to be successful. Our years of experience and commitment to offering quality products has allowed us to manufacture a brilliant line of affordable speakers with the same DNA as our $30,000 offerings.

A Quick Overview of the C-Series

  • Aluminium dome tweeter with 'tangerine' waveguide which disperses sweet, natural sound with stunning clarity evenly throughout your listening space
  • Ultra rigid enclosures and magnetic shielding guarantees unrestricted freedom of positioning
  • Gold plated terminals for improve acoustic definition with better connections to your cables
  • Invisible keyhole wall mounting system gets rid of ugly brackets to wall-mount bookshelf models
  • KEF's 5 Year Warranty
  • Click here for more information on our C-Series line of speakers

Check them out, you'll be surprised at how much speaker you can buy for not a lot of money.

Jack Sharkey for KEF America

Wednesday
Jun 18 2014

Let's Talk About Cables

Here's a cute story in case you're not sure where I'm going to go with this piece:

recently commented on the London Heathrow Hi Fi Show, saying that among the cables selling for up to £30,000 for 6 metres, they found [a competitor] demonstrating their latest speakers to great enthusiasm. The orange speaker cables looked oddly familiar. When asked about it, the recording engineer demonstrating them (who'd used the speakers as monitors while recording Saint-Saen's complete works for piano & orchestra, Gramophone's Record of the Year), said of the cables:

"Yes, they would look familiar if you have a garden. Before the show opened we went over the road to the DIY superstore and bought one of those £20 extension leads that Black & Decker sells for electric hedge-cutters. They are made from good, thick copper wire, look nice and sound good to me. The show's been running for three days and no one in the audience has noticed..."

I recently remodeled a room in our house, turning it into a den of sorts and installed a second audio system in it. It's not a big deal system, just an old receiver, an old CD player and a pair of two-way bookshelf speakers I've had laying around forever. I keep a box of cables that I've acquired over the years in the basement. In it, I can find anything from IEC power cables to special XLR cable adapters I've made to the cheap little RCA cables that come with your new amps and DVD players and stuff.

I needed a power cord for the old receiver and an eight foot speaker cable run for the audio system in the den, so down to the box I went. Much to my non-surprise I found a ten foot run of ( insert name of major cable manufacturer here ) that I've had hooked up to various systems since 1991, or have recently just let lay around in the basement. It's safe to say the cables are broken in. I also found a nice 1 meter IEC cable for the receiver.

But let's say I wasn't a electronic gizmo pack rat and I couldn't find these things...

[Cue Dream Sequence Segue Music]

Audiophile Dream Sequence

Here I am, in our Audiophile Dream Sequence doing a search on the Googleyweb for audiophile cables. Specifically right now I am searching for an IEC cable for my receiver. The reader should also take note that in this dream sequence I am sitting in a Ferrari Testarossa and tooling around the south of France while cracking wise with Scary Spice and my neighbor's dog (who is sitting in the front seat).

During my Internet search (which does not in any way interfere with my driving) I come across this fabulous power cable product on eBay:

A used, 2 meter power cable that is selling for $688:

The ( name of cable ) applies ( name of manufacturer's ) latest ( name of technology) technology to significantly advance the audio performance of AC wiring. It uses six close tolerance 16AWG, 99.99999% oxygen-free copper conductors, each covered by an 85 micron layer of extruded silver, suspended in a dual mono-filament matrix and enclosed in the (name of technology) shield.

The result is a new level of power transmission efficiency coupled to superb mechanical damping and rejection of external RFI/EMI interference. The separate, solid-core conductors eliminate strand interaction, hot spots, and other artifacts that can degrade performance, while the extreme precision with which the (name of technology) tubes are manufactured and arranged ensures complete consistency in performance. Let (name of manufacturer) feed your system and get ready for improved noise floor and resolution, increased transparency, dynamic range and freedom from grain, more believable sound staging, more natural life and musical dynamics, and a breathtaking range of tonal colors.

Suddenly the music will step away from the system producing it, taking on a life of its own, becoming a real performance all because the power on which your system depends is cleaner and arriving quicker.

  • Insulation: High purity class 1.003 Fluorinated Ethylene Propylene (FEP)
  • Construction: (name of technology and (name of technology) mono-filament design
  • Conductors: 7 x 15 AWG solid core conductors
  • Material: 80 microns of silver over 99.999999% OFC
  • Capacitance: 19.0 pF/ft
  • Connectors: IEC/Wall Plug (US)
  • Propagation: 86% the Speed of Light
  • Overall Shield Coverage: 100%

With a nifty downshift and a wry smile to my neighbor's dog (who is wearing goggles), I click the buy tab and solve my power problem.

Next, Scary apparently gets annoyed at having to sit in the back seat and she suddenly morphs into my 2nd Grade teacher who didn't like children as much as she liked bourbon. We pull into a scenic overlook as I continue my search. Lo and behold I find a nice $950 pair of speaker cables that fit most snugly into my budget. A little overwhelmed from the marketing schpiel in the power cable copy, the speaker cable copy is much more straight-forward and trustworthy:

Constructed of pure silver over a stabilizing strand of oxygen-free copper, woven into our patented hollow oval geometry in an oval-coaxial configuration.

I'm rather liking that my new speaker cables are oval rather than round because everybody knows that round cable is inherently flawed because it " has high levels of current bunching, [and] skin effect phenomenon ," (at least that's my new speaker cable manufacturer says). However, the thought occurred to me that I might not have the time to devote to breaking in my speaker cables (what with working and eating and binge-watching Game of Thrones and all), so I decided it would be a good idea to pay someone else to do it for me.

I didn't find a separate company that breaks in speaker cables, but I did find a company that built a special machine to do it for you before they ship your cables to you (allow an extra 5 to 7 days). I immediately changed course and went with this manufacturer who will allow me to pay an extra couple of hundred dollars to break-in my new $1200 pair of 2 meter speaker cables.

Convinced I was buying exactly what I needed, I hit the buy tab and then suddenly realized (a la Elvis Costello) that I needed a volume knob for my receiver because it was old and it broke.

Still in my dream and finding myself alone at an Internet Cafe in the middle of Red Square in Moscow populated with Water Buffalo, I do a quick Interweb search for "$485 wooden volume knob" (remember, we're in a dream, so that makes sense) and lo and behold, shazam! Look what I find:

"Dynamics are better and overall naturalness is improved. Here is a test for all you Silver Rock owners. Try removing the bakelite knobs and listen. You will be shocked by this! The signature knobs will have an even greater effect…really amazing! The point here is the micro vibrations created by the volume pots and knobs find their way into the delicate signal path and cause degradation (Bad vibrations equal bad sound). With the signature knobs micro vibrations from the C37 concept of wood, bronze and the lacquer itself compensate for the volume pots and provide (Good Vibrations) our ear/brain combination like to hear…way better sound!!"

Because my cables will inevitably find themselves laying on the floor, I also bought a pair of cable bridges to isolate my new speaker cables from mechanical vibrations.

All set with only the best in audio cables (for you continuity error lovers out there, ignore the fact that I didn't even worry about component inter-connect cables during my dream), I found myself falling, Super Mario-like, into a doughnut shop in Aurora, Illinois.

Luckily, right before I fell into a vat of Boston Creme, I woke up.

Now That We're Awake and Reasonable, Let's Talk About Power Cables

The power cable I bought in my dream claimed it was 99.99999% oxygen-free.

Claim: Scientists have found a way to reduce the oxygen in copper alloys which theoretically increases the conductivity of the cable.

Truth: Conductivity specifications for regular old C11000 ETP copper (Electrolytic-Tough-Pitch) is exactly the same as the conductivity spec for more expensive C10200 Oxygen Free copper (OFC). Super-expensive C10100 copper which is highly refined with virtually no impurities and an oxygen level of 0.0005% boasts a full 1% in increased conductivity , which means absolutely nothing at the power and frequency levels we're talking about. While it is true that purer copper will take longer to corrode or pit, we're talking over the course of years into decades for that corrosion to occur to a point that it messes with your audio signal in an environmentally stable environment like your house.

As far as insulation and construction goes, take a minute and walk outside and look up at the utility pole outside of your house. See those steel cables up on the top? That's where your power comes from. Then it goes into your house and magically squirts out of the wall socket. If you think a good insulator, etc. is going to clean that power up, I've got some cable I'd like to sell you. And anyway, highly paid, educated people we call electrical engineers design circuits to filter the power inside of the individual components in your system. Spend the money on good components that are well-designed on the inside and you won't have to worry about how clean the power is on the outside.

But Let's Not Forget Propagation

Without getting too involved in Velocity Factor, or Velocity of Propagation (VOP) , and the speed of a signal in a cable, let's just say this: Theoretically, a signal such as a radio signal or electrical impulse moves at the speed of light in a vacuum. It has a Velocity Factor of unity or 100%. Sticking a signal in a cable slows it down. A typical VOP for a standard cable used for audio applications is around 80%. Eighty per cent of 186,000 miles per second is 148,800 miles per second which seems pretty fast. In fact, delay over a cable is inversely proportional to its VOP, so for our purposes a cable with a VOP of 80% introduces a signal delay of 20% from one end of the cable to another. In high-frequency applications where the wavelength approaches the propagation delay or in critical systems like navigation systems, a delay of 20% is unacceptable. In the power cable going into your stereo, the signal is pretty much constant (60Hz) so the delay is meaningless. In an audio system if the delay is uniform and doesn't cause a shift in phase, then it is also not an issue.

Oval Speaker Cables Or Something Like That

Current Bunching

Claim: Due to things like cable resonance and current return flow, electrons "bunch up" or slow down while traveling along a conductor or cable. This makes your music sound sucky.

Truth: Current bunching is a thing, but mostly between the P and N layers of a semiconductor and the effect can really cause you problems along the " standard c-direction of the nitride semiconductor lattice. " In audio applications, not so much. If current bunching were really a problem those high-frequency hi-hats in your favorite Parliament Funkadelic record would always by a beat or two behind the groove.

Skin Effect

Claim: Skin effect causes high frequency signals to travel on the outside of the cable reducing the fidelity or something bad that you should spend more money to avoid.

Truth: Alternating currents (like audio signals) do indeed tend to gravitate toward the outside of a conductor ( skin effect ), but this is pretty frequency related. At microwave frequencies conductors that basically look like pipes are used because the signal only travels on the outside. But at the very upper limit of the audio spectrum (20kHz) the skin effect is so small as to be negligible (assuming a normal cable run as found in a normal house). At 20kHz a 22AWG cable "uses" 100% of the conductor while a 12AWG cable (common audio size) "uses" 75% of the cable. But, there is more "skin" or outside surface on a 12AWG cable then on a 22AWG cable, so the net effect is negligible at worst.

Capacitance and resistance of the cable is what is going to get you, but if you are buying quality cable from a reputable manufacturer (not a snake oil purveyor), the capacitance and resistance will be well within proper bounds.

Speaker Cable Break-In

Claim: The atomic elements of a piece of wire endure tremendous stress when forced through a die at thousands of pounds of pressure and then are suddenly cooled upon extrusion. This stress creates an impediment for the electrons as they begin their journey along the conductors when first put into service.

Truth: Ummm, even if this was a thing, you could just plug your cables in and let them play for a few milli-seconds and that would go away. Like everyone else, I hate when my atomic elements are stressed out, but it never seems to last long and my atomic elements, like those in a cable, are pretty able to shake off all that stress.

Claim: The insulation absorbs energy from the conductor when music is playing. This energy-absorption causes the dielectric's molecules to re-arrange themselves from a random order into a uniform order. When the molecules have been rearranged, the dielectric will absorb less energy and consequently cause less distortion.

Truth: Ummm, besides making my head hurt trying to understand what exactly this manufacturer is trying to say, any re-arranging of molecules is going to happen nearly instantaneously and not cumulatively, meaning that the molecules in a cable are not trained to stand around in a specific order by your amplifier.

Claim: Purer material requires less break-in, but silver "seems to require even more break-in" than does copper.

Truth: Ummmm, I have no idea what any of this means except that this is really convenient for a company selling a cable break-in service with their special cable break-in machines because silver is also more expensive than copper, so if you're going to spend the money on silver you might as well get the cables broken in so they'll sound great out of the box. If you have actually heard a difference between cables that were broken in versus cables that were not broken in, please drop me a line and I'll give you equal time to 'splain yourself.

My New Favorite Thing In the World! A Special Wooden Volume Knob To Make Your Stereo Sound Better!

Claim: Volume and control knobs vibrate and send those vibrations back into the audio circuits which messes up your sound. These special wooden knobs send "good" vibrations that you will find pleasing to hear back into the audio circuitry. Heck, if the vibrations are going to be there, you might as well get the most out of them!

Truth: Hahahahahahahahaha!

The Cable Bridge

Claim: Cables resonate! At $229 each, it's well worth the price to keep the floor from vibrating and resonating with your funk.

Truth: Among the sillier things, as if the wooden volume knob isn't silly enough, that I've seen is the Cable Bridge that purports to prevent mechanical vibrations from interfering with the music that is otherwise happily traveling along in your speaker cables. The manufacturer suggests two per cable (regardless of length or floor composition). Even though some folk claim that speaker cables resonate in the audio range, cables are distributed elements, therefore they should be considered to react like an infinite number of inductive elements, which in turn makes the resonant frequency of the cable go to infinity (and beyond).

As far as music in a speaker cable being susceptible to the plodding footsteps of your clod-like teenager who insists on walking to the refrigerator while you are listening to Dark Side of the Moon, that's all in your head.

The Skinny

I use the best cables I can afford based on the system I am setting up. There are some excellent cable manufacturers who design cables and insulators to be tough, resilient, with low capacitance and resistance, and who design terminations to be equally tough and tarnish- and corrosion-resistant. If you've got the money, you should buy them and keep your system filled with quality components.

Keep your cables as short as possible, but not shorter, and remember that the transducer (speaker) is the mechanical device that will affect your music the most. Spend your money on your speakers and your amps first. High-end cables look very cool and add a certain panache to your system, but you can enjoy your music plenty without them.

We audio enthusiasts often suffer from hearing what we want to hear, regardless of what we are actually hearing. So as always, if it sounds better to you, then it is in fact better. If $8500 speaker cables make your music sound better and you've got the $17,000 to buy them (for the pair), go for it. If all you can afford is a spool of 12AWG from Home Depot but you love your music when you listen to it, that's what matters ain't it? In fact, I'd rather listen to music on your system (in case you were thinking of inviting me over) because first and foremost, listening is about the music.

A Cute Story To End This Rather Bloviated Piece

Bobby Owsinki is a renowned producer and engineer who writes a brilliant Blog about trends and developments in the music industry with a concentration on the pro-audio side. He tells a great story about a switch on a console in a recording studio:

I worked in a studio once that had a 3-way toggle switched on a panel at the edge of the console. The switch wasn't wired to anything (the console's previous owner installed it), but a bunch of us decided to label it anyway in the middle of blowing off some steam during an especially long session. The Aphex process ( read here for more on Aphex the process, not the company) was especially hot during those days, so that's what we labeled the top position. Someone had the bright idea to label the bottom position as "B-phex" (there was no such thing), and the middle position was off.

You wouldn't believe the number of clients that swore that B-phex sounded much better than either Aphex or Off. Sometimes they would even fight over which sounded better, with some swearing that Aphex was brighter and more natural than B-phex, or vice versa. Even after I told them in a laugh, they still claimed they heard the difference between the positions of the unconnected switch.

Driving around the south of France in a Ferrari with Scary Spice and my neigbor's dog is the product of an over-active imagination and possibly the burrito I had for dinner last night. Unfortunately, the audio devices I talked about in this piece are real (even though the knob company has since gone under), and are damaging to anyone who loves music and audio, either on my end of the business or on the consumer's end of the business.

I may raise the ire of some, but as a guy who works for a legitimate audio manufacturer that cares deeply about music and the science of sound, I feel I have an obligation to let people know that there are some in our industry who are completely willing to take advantage of the fact that most people do not understand the science involved in recreating music and sound.

Jack Sharkey for KEF America

Disclaimer: The opinions expressed in this piece (and in the dream sequence that makes up a major part of this piece), are mine and mine alone and they do not reflect the opinions of anybody else but me. That being said, even though the opinions in this piece are pretty spot on, if you feel the need to yell at anyone about the opinions expressed in this piece, by all means drop me line (you can click my name above and send me an email).

Thursday
May 29 2014

1563 Words About Bi-Wiring

In today's episode we're going to take an in-depth look at bi-wiring. This article (and yesterday's article about bi-amplification) are simply technical looks (salted with some of my own opinion) on the subject, and aren't really meant to offer advice either way.

Tell Me Bi-Wiring Isn't Just A Ploy To Get Me To Buy More Cable

Bi-wiring is the use of two separate cables from the same amplifier to the MF/HF and the LF terminals, respectively, on your loudspeakers. While I can't tell you how to spend your money, I can give you some information to help you make a good choice for yourself.

Here's The Theory

In a bi-wired system the single output of the amplifier is connected separately to the MF/HF crossover and the LF crossover through the use of the separate terminals for each on the back of your speaker cabinet.

Because of electrical reactance, this separation creates a de facto filter because the cable connecting the MF/HF presents a higher impedance to the amplifier during low frequencies while the cable connecting the LF presents a higher impedance to the amplifier during high frequencies. Therefore, high frequencies will tend to travel through the cable connected to the MF/HF crossover and low frequencies will travel through the cable connected to the LF crossover. We are reminded that electrical current will pick the path of least resistance (or in this case impedance and reactance).

People Who Swear By Bi-Wiring Say This:

There are some who say that horizontal bi-amplification sounds better not because of the separation of the amplifiers but because of the separation of the cables feeding the speakers from the amplifiers . This is believed to happen because of the Hall Effect developed with low frequencies.

Technical Definition of Hall Effect For Those Of You Who Really Aren't That Interested:

The Hall Effect is the magnetic field developed across a conductor that is transverse (perpendicular) to the voltage on that conductor blah blah blah and is defined as the ratio of the induced electric field to the blah blah magnetic field and something to do with electrons, holes and ions and other stuff that Edwin Hall discovered in 1879 but nobody cared about until it really messed up early semiconductors.

Basically, electrical conductors (in this case cables) become magnetically charged as a result of the electrical energy running through them. This is why you're never supposed to run cables parallel and perpendicular to each other.

Proponents of bi-wiring claim that the MF and HF benefit the most because the low current MF and HF signals do not have to travel on the same wire as the high-current LF energy. This leaves the HF and MF free from the disruption caused by the high-current LF field fluctuations and CEMF.

Some people who swear by bi-wiring also claim that you can choose cables that are specifically designed to operate with specific frequencies, further enhancing your sonic reproduction.

Others claim that you can hear an enhanced "airiness" or more well-defined soundstage with bi-wiring. I have experienced this, but in all honesty after a while every song I listened to - regardless of the production and mix - started to sound identically "airy" so I'm not sure if I was listening to an improvement or a sound effect caused by the wiring. I will say that after a while it began to irritate me, but I still can't say for sure if I was actually hearing an irritant or making one up through my own psycho-acoustic response. In either case, the effect was subtle and whether it was "good" or not was strictly subjective.

People Who Will Make Fun Of You For Bi-Wiring Will Say This:

  1. There is no electrical difference between a run of standard gauge cable from your amp to the two terminals on a speaker cabinet and a single run of cable from the amp to one terminal that has a jumper to the other terminal. Meaning: If bi-wiring were actually a thing, the jumpers on your speaker's terminal plate would indeed perform the same function as two separate cable runs.
  2. Counter Electro-Motive Force (CEMF) from a woofer will be at such a small current (and at the same frequency the woofer just produced) that any current that washes back into the crossover circuit will be either a) inconsequential, or b) filtered out by the MF/HF crossover (like it was designed to do). Read more about CEMF at )
  3. Due to skin effect on the cable, higher frequencies tend to travel on the outside of the cable and lower frequencies on the inside, but this is all baloney anyway because the frequencies found in music aren't high enough to produce any appreciable skin effect.
  4. And anyway, due to certain principles of superposition , signals with differing frequencies don't interfere with each other. If you think of a musical passage traveling through a wire as a bunch of different frequencies all busily speeding toward your speaker on separate missions, bi-wiring would have some merit, but that's not how musical passages travel down cables.
  5. And double anyway, that's why you need a crossover in the first place: To separate all of those busy little signals from each other into frequencies the specified loudspeakers can reproduce without going pop . Or buzz .

So Is Bi-Wiring Better Or Not?

Yes. And No. And I don't know. It depends on who you talk to. Half the people you talk to will swear by it, half the people you talk to will ridicule you for even thinking about it, and half the people you talk to about it will offer no opinion whatsoever.

Higher-end, quality speakers generally come with two sets of terminals, and two distinct signal paths to the respective crossovers, because the end user of a speaker deserves the opportunity to figure out what sounds better for him or herself.

Caution! Opinion Below

Again with the opinions.

Personally, from a current flow and superposition point-of-view, I don't really buy into the principle that frequencies will seek out the proper cable run because of the impedance presented on that cable. The impedance is constantly changing and so is the superpositioned signal. Because of superpositioning, I also don't view the signals created by a cymbal as finding its own path on a cable separate from the signal created by a kick drum.

I can admit to having experienced a difference with bi-wiring compared to mono-wiring a set of loudspeakers, but as I explained above, what I was hearing was not the music but the speakers and set-up which I found distracting and somewhat unpleasant, under those specific circumstances. I have also done A-B comparisons with bi-wiring in several other instances and I didn't hear a difference.

And I don't really even know if what I heard was real or the result of my own psycho-acoustic interpretation. And before you go shouting I knew it! you have your own psycho-acoustic interpretations of the things you hear as well. Which brings us back to the constant struggle in the audio world: separating the subjective data our brains think our ears are hearing from the actual physics of what we are hearing.

Here's Some Good Advice Concerning Cables No Matter Which Way You Choose To Go

Regardless of whether you bi-wire or mono-wire your system, your speaker cables should be the same length. Cable runs of differing lengths can present phasing issues and imaging deficiencies.

To reduce the chance of picking up noise along the way, the shorter your speaker cables the better. If necessary for aesthetics and wife approval, it's better for your line cables and interconnects to be longer so you can make your speaker runs as short as is practicable.

Use the same type speaker cable for all runs, whether you are going bi-wire or mono-wire. Different cables may have different physical make-ups and those differences may result in sonic inconsistencies. In the frequency ranges we're talking about, a cable that transmits 80Hz well will very likely transmit 10,500Hz equally well, but a cable that has more of one type of metal in it may wind up sounding completely different than a cable with a different physical makeup.

Use the best quality cable you can afford, not less and not more, and never use smaller (higher number) than 12AWG cable for a standard two channel loudspeaker setup. Smaller gauges can be used for rear channels in small systems or for certain custom installation configurations like sub-6" speakers in low-power systems.

In spite of my acknowledgement above that physical composition does indeed have an effect on sonic response, I'll save my thoughts on cable construction etcetera for some other article some time when I am not so concerned about hurting people's feelings.

So, In Conclusion

It's not a big technical challenge to experiment with bi-wiring and all you'll be risking financially is another set of speaker cable runs. Have some fun, try it out (do your A to B comparisons with the same music). Maybe you'll love it, maybe you'll hate it, or maybe you won't hear any difference. I really can't tell you anything more than that KEF offers bi-wire/bi-amplification terminals on most of its passive product in order to give our customers the options they may want, so have at it. Maybe you'll hear something you like.

Jack Sharkey for KEF America

Tuesday
May 27 2014

1611 Words About Bi-Amplification

Today, I'm going to talk to you about bi-amplification. I would like to do it in a straight-forward, easy to write, easy to read, fun and exciting manner.

That's not possible.

But here goes.

First, Let's Clear Up Some Confusion

Bi-wiring and bi-amping are not the same thing. Also, what you probably think of as bi-amping is probably not actual bi-amping.

Multi-amp: All frequencies are run through the pre-amp and amplifier and are presented at the speaker terminal

Bi-amp: LF and MF/HF (or LF/MF and HF) are split into two signal paths prior to the amplifier before presenting two separate signals (LF and MF/HF or LF/MF and HF) at the specified speaker terminal

Tri-amp: LF, MF and HF are split into three signal paths prior to the amplifer before presenting three separate signals (LF,MF,HF) at the specified speaker terminal

An active subwoofer being sourced by a receiver's sub out is a basic form of bi-amping. A tri-amped front-of-house system. HF, MF and LF. Picture copyright Wagtechsound.

Now that you're less confused, let's move on...

Actual Bi-Amping

Bi-amping (and tri-amping) is pretty much a necessity in the pro-audio world. This is because the amount of power needed to make all of those lip-synching artists sound so loud in your local hockey arena could make your head explode (literally and figuratively).

Without bi- and tri-amping that insane amount of power would be exponentially greater. This is because in multi-amped systems passive crossovers are used and passive crossovers suck up an amazing amount of power and turn it into heat. Couple that with the need for concert audio systems to be somewhat modular to adjust for differences in hall and arena sizes (not to mention outdoor gigs), and the only feasible way to make an act sound decent without shutting down the local power grid is to tri-amp or bi-amp the audio.

This is accomplished through the use of active crossovers and people who know how to set them. Active crossovers are placed between the source and the amplifier and are individually adjusted for the speakers that make up the lows, mids and highs (think about the link between the amplifier and your CD player at home or the digital file reproducing your favorite artist's vocals while she dances and pretends to sing at that concert you just spent a fortune on).

If you are not using an active crossover between the source and the amplifier, you are not actually bi-amping anything, but to make you feel better the audio gods have coined the term "passive bi-amping." To truly bi-amp your home system, you will have to remove the passive crossovers from the speaker cabinets and use a line-level active crossover in the signal chain above the amps. But if you've spent a fortune on a good pair of speakers with well-designed passive crossovers, it seems kind of dumb to pull the crossovers out in order to save a few watts of power or reduce some theoretical intermodulation distortion (IM).

Also, keep this in mind: Unless you are pulling out the passive crossovers and replacing them with a well-tuned and highly stable active crossover network, and then tuning that active crossover properly with the proper test equipment, the power benefits you are gaining will probably not be worth the extra money.

In terms of intermodulation distortion, you are basically replacing one circuit that may or may not cause IM with another circuit that may or may not cause IM. If you've bought a decent pair of speakers with a well-designed passive crossover network you may not realize any noticeable gains, and in fact, unless you know how to set an active crossover, you are more than likely causing more harm to your overall sound quality than if you had just left your system alone.

What About Power?

A passive crossover uses inductors, resistors and capacitors. Capacitors not so much, but inductors and resistors take a lot of the power they receive and turn it into heat before it gets a chance to be turned into sound. This is why systems in commercial venues need to use active (electronic) crossovers to get the job done. So, if you're "bi-amping" your home system but still using the factory installed passive crossovers, the gain in power efficiency you were looking for when you went to bi-amp in the first place will be negligible because of all of those energy-to-heat-transferring resistors and inductors. Granted, the MF/HF may be powered with a lower power amp, therefore creating less chance for harmonic distortion, but if you're going to run that low power through a passive network, you're going to need to increase the output current to keep up with your low frequencies.

Of course, then you have to concern yourself with matching the volume of the HF with the volume of the LF so you can listen to your music as it was intended to be listened to. This factor is often overlooked, but to my ears it's a pretty major thing.

Also, if you are not splitting the frequencies before the power amp you are not reducing the stress of frequency-related loading within the amplifier circuit and power supply as the amps are receiving the full frequency range. This means that the amp is producing the full frequency range and presenting it to the speakers regardless of what you want it to do.


Horizon tal and Vertical Bi-Amping

In spite of all of this, you say you are still willing to see if a bi-amped system is right for you. Okay. Are you going to horizontally or vertically bi-amp your system? And does it matter?

In a horizontally bi-amped system, one stereo amp powers both (L & R) bass drivers and one stereo amp powers both (L & R) MF/HF drivers.

In a vertically bi-amped system, one stereo amp is used for the MF/HF and LF (L channel) and another stereo amp is used for the MF/HF and LF (R channel).

In both cases, you can think of it in terms of having four separate amplifiers.

Theoretically, a vertical system will be more efficient because the heavier loading of the lower frequencies is split between two amps (and subsequently two power supplies). Meanwhile, some people like the horizontal system because they can use one type of amp that may work better with high frequencies (like a nice low-power tube amp) and one type of amp that works better with low frequencies (like a meatier high-power solid state amp). Unfortunately, like most things in life, this sounds really neat on paper but in the real world there are unintended consequences that may cause you more aural grief than sonic joy.

  • Getting the signal levels of the two different-type amps to match is extremely hard to do without the right measurement equipment. Therefore, you may not be listening to your music with the intended balance between the highs and lows.
  • It is very difficult to get two different amplifiers with two separate sonic characteristics to play nice with each other in the midrange area (where most of the musical information resides).

So once again, if you are considering bi-amping your system, tread carefully and do as much research as you possibly can before taking the plunge. You may be better off spending your money on a really good, clean, 250WPC amp, than buying 2 125WPC amps.

There are still benefits to bi-amping (if all of the above is taken into consideration). Those benefits are:

  • Transient signals are less likely to be present within a frequency range and are therefore less likely to cause amp overloading and clipping.
  • Reduced intermodulation distortion (IM) (frequencies that are not harmonically related and that develop non-harmonic frequencies which translate to the ear as distortion).
  • Reduced interference from CEMF (counter electro-motive force). CEMF can be developed by a hard-working LF driver that theoretically "pushes" electrical energy back to the crossover or MF/HF drivers. Basically, as a driver moves back and forth, it produces a current in the voice coil. During a quiet passage immediately following a loud passage some of this CEMF may potentially interfere with other frequencies.

Caution! Opinion Below

Opinions are like bad breath, they float around and are generally something to avoid, but here's my subjective thought on bi-amping a home music system:

Unless you are willing to spend seriously large amounts of money, then you are willing to take out the crossovers that were designed for - and installed - in your speakers, and are then willing to take the time to properly set your active crossovers, I'd spend my money on a really good pair of speakers and a really good amplification/pre-amplification system and just go ahead and enjoy the music.

Can you benefit somewhat from even a passively bi-amped system? To an extent, but the return on your investment isn't enough to convince me you shouldn't just spend your money upfront on a decent to really good multi-amped system.

Another thing to consider: Our engineers spend an enormous amount of time and money getting our passive crossovers set precisely for the cabinet volume and driver configuration of our speakers so you don't have to.

There will be some who swear I am dead wrong here, but that's okay. A lot of this comes down to what we think we hear and there is nothing wrong with that, but what you've got now are the technical reasons for going one way or the other.

Take note here that monoblock systems are not bi-amped systems and aren't covered by this article.

Tomorrow I'll take my life further into my hands amongst the audio-cognoscenti as I discuss the pros and cons of bi-wiring your system.

Jack Sharkey for KEF America