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Interview with JBL's Greg Timbers


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http://positive-feedback.com/interviews/greg-timbers-jbl/

 

Maybe someone could explain in layman's terms exactly what he means below, i.e., "esoteric discrete analog stuff".

 

"By using FIR filters, amplitude and phase can be manipulated independently so this constraint can be overcome. The hardware in the DEQX is very well implemented indeed, but it is no match for the esoteric discrete analog stuff. Still, the complete amplitude and time correction easily overcomes this handicap and has given me the best of both worlds. I now have all of the detail, dynamics, smoothness and spacial attributes I have been searching for with the ability to do room correction and frequency shaping as I wish.  It is a win-win for me." 

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Maybe I missed it,  but is there a more detail about the passive/active crossover control he used? Did he effectively implement the active and the passive in the same signal path? 

Also, was he bi-amping with tube HF and solid state LF?

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Yep keep scanning down until the comments section, it gives all the components.

Quickly -

4x Parasound JC1 amps, one for each woofer

2x Quicksilver 120's for the midrang

2x Pioneer Elite A 20 for ultra high freq.

So in short yes, a blend of SS and tubes.

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[Original article in positive feedback:  http://positive-feedback.com/interviews/greg-timbers-jbl/]

 

My favorite parts of the interview that might appeal to other Klipshers, as well:

 

"Dynamics will make or break the loudspeaker system. Live music is dynamic as hell and this is one of the most difficult attributes to reproduce. Compression exists at all stages of the reproductive and recording chain. Of course, loudspeakers have the most but it is apparent in electronics as well ...

 

Where do you see the ‘sweet spot' to be in a speaker? That is the midrange, bass, treble, sound staging, efficiency, etc.)?

As I mentioned, I believe that solid Dynamic behavior is most important to get lifelike sound. Dynamics require high efficiency since transducers are pitiful in energy conversion. I also believe that sound staging is extremely important. I think natural midrange and bass presentation precedes the treble range. Of course all things have to be balanced! ...

 

How has the sound of speakers changed over the years? Many yearn for the speakers of the past over those of today… what has changed? Distortion, materials, focus on sound characteristics?

Speakers have generally become smoother, more 3-dimensional and much smaller. This means that they are less dynamic on the whole and rather toy like compared to good stuff from the 60s and 70s. Unlike electronics, miniaturization is not a good thing with loudspeakers. There is no substitute for size and horsepower. Nothing much has changed with the laws of physics in the last 100 years so what it takes to make dynamic life-like sound is unchanged. ... Now that power is cheap, size and efficiency has been thrown out the window because you can always apply more power. Unfortunately, more power does not make up for lack of efficiency. Today's speakers range between 0.1% to maybe 0.5% in efficiency. (On a good day) 60s and 70s stuff was more like 1% to 10%. With most of the losses gong to heat, turning up the power on a small system with small voice coils and poor heat management is definitely not equivalent to a large high efficient speaker.

 ... However, the big Altec's, JBL's, Klipsch's and Tannoys of the day would still fair well today with a little modernization of the enclosures and crossovers ...

Today's multi-channel home theater setups let a bunch of small toy loudspeakers and a sub or two sound pretty big and impressive to the average Joe. I think speakers have mostly become a commodity and small size and price are what counts the most now. The few high-end brands left are struggling for market share in this age of ear buds."

 

Well said!

 

 

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14 minutes ago, garyrc said:

Dynamics will make or break the loudspeaker system. Live music is dynamic as hell and this is one of the most difficult attributes to reproduce. Compression exists at all stages of the reproductive and recording chain. Of course, loudspeakers have the most but it is apparent in electronics as well ...

 

The music tracks themselves are the source of 99% of the compression described above...trust me.  If you were to source recordings without applied compression, you probably wouldn't be concerned about this in such large transducers.

 

I'm not sure what compression in the setup is left except perhaps the direct radiating woofers, which will produce group delay (sounding like compression) and real compression distortion at some SPL, along with copious amounts of AM distortion.  JBL apparently hasn't made a horn-loaded bass cabinet since the mid-1950s.  When you listen to good horn-loaded bass bins (without midbass directivity issues) vs. direct radiating woofers, you'll hear what I'm talking about. 

 

14 minutes ago, garyrc said:

Speakers have generally become smoother, more 3-dimensional and much smaller. This means that they are less dynamic on the whole and rather toy like compared to good stuff from the 60s and 70s.

 

Unlike electronics, miniaturization is not a good thing with loudspeakers. There is no substitute for size and horsepower. Nothing much has changed with the laws of physics in the last 100 years so what it takes to make dynamic life-like sound is unchanged...

 

Now that power is cheap, size and efficiency has been thrown out the window because you can always apply more power. Unfortunately, more power does not make up for lack of efficiency. Today's speakers range between 0.1% to maybe 0.5% in efficiency. (On a good day) 60s and 70s stuff was more like 1% to 10%. With most of the losses gong to heat, turning up the power on a small system with small voice coils and poor heat management is definitely not equivalent to a large high efficient speaker.

 

...However, the big Altecs, JBLs, Klipsches and Tannoys of the day would still fair well today with a little modernization of the enclosures and crossovers...

Amen.

 

14 minutes ago, garyrc said:

Today's multi-channel home theater setups let a bunch of small toy loudspeakers and a sub or two sound pretty big and impressive to the average Joe. I think speakers have mostly become a commodity and small size and price are what counts the most now. The few high-end brands left are struggling for market share in this age of ear buds.

 

The pendulum swings.  As the economy actually recovers from the Great Recession, enabling larger and more widespread disposable incomes, so will the market for new loudspeaker designs that incorporate the technological advantages of the last 40-50 years, and perhaps away from the intense current nostalgia of the mid-1950s to late-1970s.

 

Chris

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21 hours ago, Chris A said:

The music tracks themselves are the source of 99% of the compression described above...trust me. 

 

In my home studio I make drumset recordings that use no dynamic compression at all anywhere in the recording chain, and I used CDs of some of these recordings to audition various speakers when I worked at Harman. (In fact, one of the transducer engineers had me make him a copy of one of these recordings so he could use it during his evaluations, since it's almost impossible to find commercial recordings that don't incorporate dynamic compression, often so severe that the difference between loudest and softest sounds might be only around 10dB!) These uncompressed recordings ruthlessly exposed the differences in realistic-sounding presentation between higher-sensitivity speakers and lower-sensitivity ones.

 

As a rule, the higher a speaker's sensitivity the more faithfully it will reproduce the dynamic contrasts that distinguish the experience of listening to live music from listening to reproduced music. At close-to-realistic playback levels (lower-sensitivity speakers simply cannot play as loud as a real drumset would be in the room) the lower-sensitivity speakers just didn't sound as "real" — if you turned your back and walked away it was easy to tell you were listening to a recording. But higher-sensitivity models playing at the same 'almost-real' volume presented those dynamic contrasts more realistically, and were much better able to make you think you were listening to a real drumset when you had your back turned.

 

But the difference between high- and low-sensitivity speakers really becomes obvious when you turn the volume control down. As you lower the listening volume the lower-sensitivity speakers compress the music's dynamic contrasts more and more, until most of the music's subtle dynamic cues are gone (they all sound at the same volume) and the music sounds more and more like it's coming through a transistor radio. That's why some speakers simply don't "open-up" until you really crank the volume up on them. The higher the speaker's sensitivity the less susceptible they are to this phenomenon. That's why Klipsch speakers* sound much more like live music even when you're listening to them at much-lower-than-realistic volume levels: They continue to reproduce the music's dynamic contrasts without compressing them.

 

It's hard to make this comparison using commercial recordings unless you're aware of the "provenance" of their recording/mastering chain. If you can find recordings with a dynamic range that approaches that of live music they can be valuable tools for sorting out which speakers make music sound more real and which don't. 

 

*As well as higher-sensitivity JBLs, older Altecs and a few others.

 

FYI, I bring this up in this thread because I discussed the subject of dynamic compression at different listening volumes with Greg Timbers a couple of times while I was working at Harman. He told me that a good example of its importance to realistic-sounding music reproduction is when you're walking though a mall at Christmas time and hear music playing in the distance. He said that even at a distance it's always easy to tell if the music you're hearing is live or a recording, because live music will be full of dynamic information while a reproduced recording simply doesn't contain the same amount or type of dynamic contrasts. A recording/reproduction system that gets that dynamic information right will sound more like live music.

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Interesting comments.

 

The sensitivity of a speaker is overlooked in todays market of cheap wattage, but it is very important, especially (as pointed out above) in low volume (dB) situations. One of the reason I love my La Scalas and Bozaks - only a watt or three are needed and they are "clean" at low volumes.

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