Timbre Matching: Can you tell me all you know about it?

[HornEd]

Some times I get more email on Klipsch subjects than I have time to respond to... so, here's my responses to PHIL O who took the succinctly comprehensive prize with, "Can you tell me everything you know about timbre matching?" To all those who asked about timbre matching... and any other Forum Friends or Phantom Lurkers who care to know... here are some IMHO comments. -HornED

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HornEd's initial email reply:

Probably not at this point in the aging process. But I can include some way-off-the-cuff comments (since I am wearing a short sleeved Klipsch polo shirt).

Every speaker has its own timbre profile, that is to say that it processes sound in a particular way. Even two exact speakers will have subtle timbre differences beyond those that occur from a difference in positioning. The proximity from reflecting surfaces also makes a difference... just do an A/B test with the same speaker close to the floor and then raised several feet from the floor and you can get an idea how its "voice" changes.

Since "timbre matching" is an attempt to make the "voice" of each speaker sound as much the same as possible... and since so many factors conspire to make the signature "voice" of any given speaker, the potential to find different pathways to the same "voice" can be amazingly complex from a loudspeaker engineering and specific listening room acoustics perspective.

Generally speaking, using six identical monopole speakers in a 6.1 format provides a simplistic approach to timbre matching... and that is what I did for my Home Theater using KLF-30 "Legends" in each spot. Obviusly, the center channel had to be modified so that the speaker array was horizontally oriented to properly anchor the sound to the screen. From a timber matching perspective, rotating the speaker and raising above the 65" RPHD screen created the greatest timber shift among the six speakers.

By "timber shift" I mean a change in the sound character as the same sound moves from speaker to speaker in a movie's sound pan. Badly timbre matched speakers make what should be a constant sound shift like the Doppler effect that can be heard when a freight train passes while you are standing at a given point tangential to the tracks.

While there is some lattitude to engineer and/or position smaller speakers so that they more closely approach the timber match of the mains (generally those to the left and right of the screen in an HT system). Realistically, the diminshed size of most center and surround speakers forces them below the acceptability line when it comes to timbre matching qualities.

And, of course, speakers that are designed to throw multiple sonic images around the room to deny the ears ability to make critical timbre matching judgements (such as WDST speakers and even more so in units that have no speakers facing the sweet spot... and much more so in dual broad range speakers that are out-of-phase). All of these techniques are engineered to increase one's sense of ambient sound at the expense of the realism that timbre matching can bring.

Remember, at best, digital sound is an illusionary series of air pressure fluctuations that strike your ear drums and body to create a "sound" in your mind. That realization is a strong argument for letting your "ears" be the judge as to what speakers you like in your listening area... realizing that all the stuff on the input side, from electronics to wire construction, can make a differnce.

Many audiophile grade speakers are not engineered to provide the closest possible match to the original sound in nature... but rather are built to create the sound that their consumer target is likely to buy. A good example of this is the success of Bose (although admittedly not a high end speaker) to become the most profitable speaker manufacturer in the world. Bose success is an example of manufacturing what people think they should be hearing by advertising and clever demo set-ups rather than using better quality audio components with the size that it takes to build audio accuracy. The arrangement of Bose cubes is designed to kill timbre matching potential rather than to enhance it.

Since location is a distinct part of the "voice" of any speaker and location is determined by sounds roughly over about 80Hz for a period of time (a fraction of a second) before almost the same sound can be heard from a different direction (as in the original sound being reflected from a surface in the listening area)... then one perceives the original sound as coming from a certain direction with all of its unique qualities as a speaker in a certain location. Ambient sound creates the notion that you are surrounded or, perhaps, engulfed by the sound all around you... and this effect can be created by broadcasting the same sound in a wide dispersion pattern so that your ears report to your brain than the sounds from many directions are too close to be considered other than one overwhelming sound all around you.

Most of the current "Home Theater" packages feature a subwoofer for the lows and larger speakers in the conventional stereo positions... a somewhat downsized center speaker to more easily fit atop a TV... and smallish sattelite speaker to provide the surround effect. This configuration is a throwback to the ProLogic era when the surround channel was really a narrow spectrum of auditory clues (considerably over 80Hz) that would fool your ear into associating the direction of the auditory clues with some of the sounds coming from your primary speakers.

A good example of this phenomenon can be experienced by having an excellent subwoofer that only puts out sounds below the range that the human ear can detect for location purposes (generally accepted as below about 80Hz but that depends upon the individual ear... and sadly, for me, its age and "sound milage!") If you then have six closely timbre matched speakers arranged in a 6.1 configuration, your brain will tell you that the low sound you hear is coming from the speaker that is playing the above 80Hz sounds naturally associated with the low sound.

What I am trying to say is that you will hear the rumble of a tank in the back of the room even if your subwoofers are in the front of the room... providing that the attendant over 80Hz sounds of tank rumblings are coming from a rear effects speaker! An even more dramatic example is a jet fly over that comes from the back to the front of the room... the deep throated jet roar will seem to migrate from the back to the front... even though all the really deep sounds are coming from the subwoofer that may be positioned (for the sake of illustration) in the middle of the room.

Remember, that much of the really bottom scraping bass that one can perceive comes as a change of room pressure on your skin surfaces and is especially effective on your chest cavity... and may below the range that your ears can perceive sound.

An additional to the issue of timbre matching question is the placement of speakers and their dispersion angles. Generally the angle of dispersion of a single cone or horn speaker needs some distance between it and the listener to cover a broad range of the room. That means that the sweet spot will be an area inside the direct radiating scope of the six main speaker positions. This combination along with a DVD engineered to get the best out of six timbre matched speakers will, IMHO, the finest audio experience. For it allows directional sound to be fully directional and, by having the same sound broadcast from every direction (balanced for where the source, if any, is to be) for virtually any level of ambient sound. Again, the more ambient sound the less directionality... the less directionality the less timbre is a factor... and the less "live" the sound becomes, IMHO.

Of course, putting identical speakers firing in different directions covers the room in shorter distances and makes the speaker system less dependant on room acoustics to recreate the original sound. But, of course, the original sound is not likely to be the one now replecated by a barrage of speakers aimed everywhere. However it is cheaper to make and market little ambient jewels than it is to build big mouth monopoles that speak more truth.

The often ridiculed sound altering electronics that make a room sound more like a huge stadium, or an intimate jazz club, or a cavernous cathedral are related to this issue of how much of what kind of sound is broadcast from which set of speakers. While such overt tricks being played on one's ears brings out the hostility in some... those same kind of tricks are played by most speaker manufacturers in their attempt to capture market share. And, let's face it, if they don't capture sufficient market share they will cease to exist in a competative economy... whatever the purest audio engineering points may be.

When Paul W. Klipsch heard Bell Labs "three channel stereo" long after he designed the first Klipschorn, he was enthralled with its "real life" rendition of concerthall sound. While, ideally he would probably have preferred three Klipschorns... his practical notions... and the aethetic sensibilities of his wife of that era... forced him to think of a whole series of speakers that first brought the LaScala as a cornerless Klipschorn... and, finally, the more difficult to build wife pleaser that was named Belle after his wife. Listening to a properly set up pair of Klipschorns with a Belle in the middle is an excellent example of timbre matching of somewhat dissimilar speaker designs orchestrated into a supurb listening experience... particularly for concert hall material where one's perspective is usually that of being in the audience.

In an HT environment, the challenge is to place the listener in a sweet spot and be able to hit him with the same sounding explosion or machine gun that seems to come, by design, from any particualr place in the room... or maybe right under his chair... or above his head! With full spectrum sound in all five or six non subwoofer channels available on modern DVD's, sound engineers are able to create more full scale reality than ever before... and that is where I believe we are headed as audio consumers as audio engineers increase their skill sets when making movies. What's slowing the process down... just the knowledge, experience and pocket money it takes to put together a really great, timbre matched sound experience.

Oh, yes, and the decline in popularity of the "Bose Bourgeois" as the epitomy of good sound which by their mishapen notion means itsy bitsy, teenie weenie, polkadot sized bikini speakers.

Thanks for the question, PHIL O, I might just put your answer on the forum since it raises an issue that people frequently right me about and I have less time these days to respond. -HornED

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HornED's timbre matching follow-up email to Phil O.

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Since "timbre matching" is an attempt to make the "voice" of each speaker sound as much the same as possible... and since so many factors conspire to make the signature "voice" of any given speaker, the potential to find different pathways to the same "voice" can be amazingly complex from a loudspeaker engineering and specific listening room acoustics perspective.

Generally speaking, using six identical monopole speakers in a 6.1 format provides a simplistic approach to timbre matching... and that is what I did for my Home Theater using KLF-30 "Legends" in each spot. Obviusly, the center channel had to be modified so that the speaker array was horizontally oriented to properly anchor the sound to the screen. From a timber matching perspective, rotating the speaker and raising above the 65" RPHD screen created the greatest timber shift among the six speakers.

By "timber shift" I mean a change in the sound character as the same sound moves from speaker to speaker in a movie's sound pan. Badly timbre matched speakers make what should be a constant sound shift like the Doppler effect that can be heard when a freight train passes while you are standing at a given point tangential to the tracks.

While there is some lattitude to engineer and/or position smaller speakers so that they more closely approach the timber match of the mains (generally those to the left and right of the screen in an HT system). Realistically, the diminshed size of most center and surround speakers forces them below the acceptability line when it comes to timbre matching qualities.

And, of course, speakers that are designed to throw multiple sonic images around the room to deny the ears ability to make critical timbre matching judgements (such as WDST speakers and even more so in units that have no speakers facing the sweet spot... and much more so in dual broad range speakers that are out-of-phase). All of these techniques are engineered to increase one's sense of ambient sound at the expense of the realism that timbre matching can bring.

Remember, at best, digital sound is an illusionary series of air pressure fluctuations that strike your ear drums and body to create a "sound" in your mind. That realization is a strong argument for letting your "ears" be the judge as to what speakers you like in your listening area... realizing that all the stuff on the input side, from electronics to wire construction, can make a differnce.

Many audiophile grade speakers are not engineered to provide the closest possible match to the original sound in nature... but rather are built to create the sound that their consumer target is likely to buy. A good example of this is the success of Bose (although admittedly not a high end speaker) to become the most profitable speaker manufacturer in the world. Bose success is an example of manufacturing what people think they should be hearing by advertising and clever demo set-ups rather than using better quality audio components with the size that it takes to build audio accuracy. The arrangement of Bose cubes is designed to kill timbre matching potential rather than to enhance it.

Since location is a distinct part of the "voice" of any speaker and location is determined by sounds roughly over about 80Hz for a period of time (a fraction of a second) before almost the same sound can be heard from a different direction (as in the original sound being reflected from a surface in the listening area)... then one perceives the original sound as coming from a certain direction with all of its unique qualities as a speaker in a certain location. Ambient sound creates the notion that you are surrounded or, perhaps, engulfed by the sound all around you... and this effect can be created by broadcasting the same sound in a wide dispersion pattern so that your ears report to your brain than the sounds from many directions are too close to be considered other than one overwhelming sound all around you.

Most of the current "Home Theater" packages feature a subwoofer for the lows and larger speakers in the conventional stereo positions... a somewhat downsized center speaker to more easily fit atop a TV... and smallish sattelite speaker to provide the surround effect. This configuration is a throwback to the ProLogic era when the surround channel was really a narrow spectrum of auditory clues (considerably over 80Hz) that would fool your ear into associating the direction of the auditory clues with some of the sounds coming from your primary speakers.

A good example of this phenomenon can be experienced by having an excellent subwoofer that only puts out sounds below the range that the human ear can detect for location purposes (generally accepted as below about 80Hz but that depends upon the individual ear... and sadly, for me, its age and "sound milage!") If you then have six closely timbre matched speakers arranged in a 6.1 configuration, your brain will tell you that the low sound you hear is coming from the speaker that is playing the above 80Hz sounds naturally associated with the low sound.

What I am trying to say is that you will hear the rumble of a tank in the back of the room even if your subwoofers are in the front of the room... providing that the attendant over 80Hz sounds of tank rumblings are coming from a rear effects speaker! An even more dramatic example is a jet fly over that comes from the back to the front of the room... the deep throated jet roar will seem to migrate from the back to the front... even though all the really deep sounds are coming from the subwoofer that may be positioned (for the sake of illustration) in the middle of the room.

Remember, that much of the really bottom scraping bass that one can perceive comes as a change of room pressure on your skin surfaces and is especially effective on your chest cavity... and may below the range that your ears can perceive sound.

An additional to the issue of timbre matching question is the placement of speakers and their dispersion angles. Generally the angle of dispersion of a single cone or horn speaker needs some distance between it and the listener to cover a broad range of the room. That means that the sweet spot will be an area inside the direct radiating scope of the six main speaker positions. This combination along with a DVD engineered to get the best out of six timbre matched speakers will, IMHO, the finest audio experience. For it allows directional sound to be fully directional and, by having the same sound broadcast from every direction (balanced for where the source, if any, is to be) for virtually any level of ambient sound. Again, the more ambient sound the less directionality... the less directionality the less timbre is a factor... and the less "live" the sound becomes, IMHO.

Of course, putting identical speakers firing in different directions covers the room in shorter distances and makes the speaker system less dependant on room acoustics to recreate the original sound. But, of course, the original sound is not likely to be the one now replecated by a barrage of speakers aimed everywhere. However it is cheaper to make and market little ambient jewels than it is to build big mouth monopoles that speak more truth.

The often ridiculed sound altering electronics that make a room sound more like a huge stadium, or an intimate jazz club, or a cavernous cathedral are related to this issue of how much of what kind of sound is broadcast from which set of speakers. While such overt tricks being played on one's ears brings out the hostility in some... those same kind of tricks are played by most speaker manufacturers in their attempt to capture market share. And, let's face it, if they don't capture sufficient market share they will cease to exist in a competative economy... whatever the purest audio engineering points may be.

When Paul W. Klipsch heard Bell Labs "three channel stereo" long after he designed the first Klipschorn, he was enthralled with its "real life" rendition of concerthall sound. While, ideally he would probably have preferred three Klipschorns... his practical notions... and the aethetic sensibilities of his wife of that era... forced him to think of a whole series of speakers that first brought the LaScala as a cornerless Klipschorn... and, finally, the more difficult to build wife pleaser that was named Belle after his wife. Listening to a properly set up pair of Klipschorns with a Belle in the middle is an excellent example of timbre matching of somewhat dissimilar speaker designs orchestrated into a supurb listening experience... particularly for concert hall material where one's perspective is usually that of being in the audience.

In an HT environment, the challenge is to place the listener in a sweet spot and be able to hit him with the same sounding explosion or machine gun that seems to come, by design, from any particualr place in the room... or maybe right under his chair... or above his head! With full spectrum sound in all five or six non subwoofer channels available on modern DVD's, sound engineers are able to create more full scale reality than ever before... and that is where I believe we are headed as audio consumers as audio engineers increase their skill sets when making movies. What's slowing the process down... just the knowledge, experience and pocket money it takes to put together a really great, timbre matched sound experience.

Oh, yes, and the decline in popularity of the "Bose Bourgeois" as the epitomy of good sound which by their mishapen notion means itsy bitsy, teenie weenie, polkadot sized bikini speakers.

Thanks for the question, PHIL O, I might just put your answer on the forum since it raises an issue that people frequently right me about and I have less time these days to respond. -HornED

[IndyKlipschFan]

Horn Ed

Now this is why I subscribe and add comments to this board. I actually learn something from my fellow Klipschers...and feel some time here off and on is soo worthwhile.

Great explanation!

[jtkinney]

What HE said. Good explanation. I notice the difference now that I have an all Heritage HT, even without a sub, over the mismatched Heritage, Reference and Synergy system that I had.

[Audible Nectar]

Bumpity!! I'm putting this toward the top - this deserves to be there for a while. It is required reading for all you HT gurus or wannabe gurus out there.

HornEd's approach to timbre matching was the approach I used when putting my HT together. I don't have 6 identical mains, but I did the best that I could based on space constraints (and of course, budget). I use Cornwall II's as mains, Academy Center, and Chorus as rear in a 5.1 setup. The Chorus shares the same tweeter/squawker as the Cornwall II, and works very well. I have found that taking the time to match timbre of speakers as close as possible provides a realism that I had previously only heard in the best of theaters.

Read it, obey it, and you'll enjoy your HT that much more. When purchasing those precious Klipsch for your HT-to-be, make sure to look to the future of your system, so that the timbre agrees amongst your family of Klipsch.

Once you hear a timbre matched system, anything else will seem - well, inadequate. When it's right, you know it. I equate timbre matching to tires on cars - driving on 4 different sized, profiled, and treaded tires doesn't give a very good ride. You might think it does, until you buy that matched set of four - and you discover how "off" the ride really was. Of course, proper speaker positioning (alignment) helps even more.

[Danartdis]

First of all, another brilliantly thought out and brilliantly composed response by HornEd. I just wanted to comment that I LOVE my little timbre-matched system. I have a small group of friends that gets together once per month for the Movie Of The Month Club. We take turns hosting and its a great way to get together and a great way to check out different approaches to HT. Recently I had one of the members over for a couple of beers and to watch a couple of DVDs. His comment to me after watching to Blade II at what must have been refernce level was "You've ruined movie night!" My response was "I guess you're going to have to upgrade" Thanks again to HornEd

Dan

[HornEd]

Thanks for the meaningful comments, Forum friends. Having raced Jaguars years ago, I found the tire analogy particularly meaningful. When you take a well made sports car over 100 mph it seems suddenly be on tip-toes... ultra sensitive to the shades and nuances that fine driving demands... and no where is that more true than where the rubber meets the road and its realization in the mind of the driver... it's life... it's death... it's a trip beyond the commonplace!

To maximize joy and minimize danger to the pilot... an unbelieveable amount of detailed work goes into setting up a competative road racing machine... and even more in the critical fine tuning process that includes engine, chassis and tires.

Fortunately, the potential danger to putting a home theater through its paces is limited to one's own hearing... and that of any neighbors within earshot. Putting together a truly timbre matched system can be done with any level of Klipsch speakers. I have even heard rumors that one can do it with other brands! (Just kidding, BobG and associates) Obviously, the better quality of the speakers in a timbre matched set... the more joy occurs where the sound waves meet sweet spot "ear road"... all the way to the brain... where the illusion of sound gets its full measure from our own ultimate device... our brain. (Oops, here's where we lose the Bose enthusiasts!)

Since writing my above answer, I have been experimenting with approaches to improve the size and character of the sweet spot in a given home theater. I have come to the realization that having an expontential or Tractrix horn with a narrow dispersion angle enhances the dynamic interaction of the center main with the right and left mains when sampling well mixed DVD's... particularly in dts presentations IMHO. The second realization was the inherent value of a 7.1 configuration to enlarging the sweet spot.

To those Forum folk and loyal lurkers with big screens, the size of the screen demands (for visual purposes) that we sit much further back than the distance required to get the best from our Klipsch speakers... which highlights the benefits of a vertically mounted mid-range horn such as that in the KLF-C7. Thus, my latest center channel conversions for floorstanding speakers feature vertically oriented mid-range horns. Again, this provides the opportunity to shape the sound hitting the sweet spot with a minimal disturbance to timbre matching.

For the last couple of years, I have been less enthusiastic about 7.1 configurations (except in very large rooms) than I might have been. I was a big fan of the sixth channel as a natural extension of re-creating sound as it occurs naturally... and for spectacular (if unnatural) special effects. But, since there are no distance from the screen constraints on the rear array, the challange becomes to enlarge the sweet spot by bringing it's rear closer to the rear effects speakers. By having two rear effects speakers, the dispersion angle of the speakers over a wider area if the speakers were ideally placed along the back wall to provide the widest array of coverage in tandum. In effect, a pair of rear effects speakers can cut the effective "ideal" distance from the rear effect speaker by about two-thirds... and even more when floorstanding speakers are "horizontalized" to take advantage of a wider dispersion angle of dual speakers in a single cabinet.

Even if only one converted floorstanding speaker is used, converting the woofers to be nearer the ends of the speaker helps widen the dispersion angle and moves the rear edge of the sweet spot further back in the room. In a similar vein, turning floorstanding speakers into surround speakers by remaking the motorboard for a horizontal presentation makes a wider dispersion angle to increase ambiance without sacraficing timbre matching or directionality.

A nice touch is to buy or build shelves that support surround or rear effects speakers in a horizontal position with enough clearance for ports to be effective. That brings up some New Year's "wishes" for the folks in Indy. Rear effects and surround speakers that more closely match mains in timbre... with the speaker built to be more narrow in depth than in width and with port configurations that do not demand a large distance between the wall and the back of the speaker enclosure. Also, make available storage cabinets for CD's, DVD's and/or electronics gear that would be designed to hold a horizontalized floorstanding speaker.

Bose has been a leader in taking compromised sound into little boxes. The door is open for Klipsch to take uncompromized sound into a more practical room configuration. I am truly amazed at how many really fine homes I am invited too (for other than acoustics reasons) in which a ton of money has been spent on a high end sound system that could be put to shame by a moderately priced Klipsch system properly modified and set-up.

This "sound stuff" is getting so exciting that it has become a whole new reason to hang around this planet a bit longer. Klipsch, it's to live for! -HornED