Performance Improvements
Detail: North Creek Crossover Components are as free of parasitics as modern technology allows. Consequently, the amount of information passed through the North Creek crossovers and to the drivers is far greater than through the original crossovers. This does not change the tonality of the loudspeaker, nor does it alter its overall character. There is simply more "there" there.
Texture: Because of the increased level of information, every nuance of each instrument is clearly revealed. The amount of rosin on the bow, the endless shimmer of a cymbal, the snap of a drum head; subtleties that when absent limit the illusion. Our networks are far more revealing, and far more convincing.
Sound stage: The subtle ambiance and dimensional cues that recreate a believable sense of space tend to be absorbed by parasitics within the stock crossover components, resulting in a sound stage that is locked in the plane of the loudspeakers and bordered by the driver positions. Elimination of these parasitics moves the sound stage behind the loudspeakers and recreates a tremendous sense of volume from those recordings where the information is present. Sound stage width, height, and depth are greatly improved.
Focus: Although there is no mathematical basis to define image focus, correct sizing and stability of specific images is at least partially a product of driver matching and intercomponent variation in the crossover network. B&W matches the raw drivers at their factory to within 1 dB, which is excellent. Component variations within the factory networks are ±5%, which also can amount to ±1 dB of variation. The result is possible variation of up to 4 dB within left/right pairs. Believe it or not, this is considered quite good for a production loudspeaker.
The North Creek Networks are constructed of raw components hand matched to ±1%, 500% better than the stock network. The resulting maximum left/right pair variation is dominated by driver variation and limited to 2.2 dB.
Our level of pair matching, the clarity of our crossover components, and the excellence of the original design gives the updated loudspeaker extraordinary focus. On properly recorded performances, the precision, correct sizing and placement of individual performers is unprecedented.
Dynamics: Loosely defined as the difference between the loudest and quietest sound of a passage, the dynamics of the stock loudspeaker are constrained by the dynamic instability of the components in the original network. This is called dynamic compression, and can be detected as a lack of impact in the low end, hardness and a lack of clarity in the midrange, and in the upper frequency range as a masking of detail. Dynamic compression occurs both with transient information that is much louder than the average playback level, and with continuous mid-level playback.
One source of dynamic compression in the stock networks is sand cast resistors, which have a temperature coefficient (Tc) of about 400ppm/°C; that is, their resistance increases substantially when they operate at higher temperatures. Because they heat up instantaneously as current passes through them, they have a higher resistance to loud sounds than they do to quiet sounds - so they let proportionally less of the loud sounds through. North Creek Resistors have a Tc of less than 50ppm/°C, 800% better than sand cast resistors, and are not a source of dynamic compression.
The stock 801 and 802 crossover networks also use ferrite cored inductors throughout. Ferrite cored inductors suffer from dynamic compression through a phenomenon known as hysteresis, where energy is wasted through switching the magnetic direction of the ferrite. So much energy is lost in this manner that if one were to put their ear against the inductor during a musical passage, one would hear the core "humm along," acting precisely like a solenoid.
The North Creek Crossovers use strictly air-cored inductors, and absolutely do not suffer from hysteresis distortion. So when a bass drum goes "boom" through the stock crossover, it goes "WHAM!" through the North Creek version.
Harmonic Integrity: The most endearing quality of the stock 801 and 802 is their natural overall presentation of the musical event. This can at least be partially attributed to their ruler-flat frequency response, excellent dispersion, and extremely broad bandwidth.
Because the North Creek Crossovers are not redesigns of the original units, they do not change any of these characteristics. However, because they let so much more information through, the harmonic integrity of the loudspeakers is improved.
Musicality: This is the one true measure of a loudspeaker, and in this aspect, beyond all others, the North Creek Crossovers excel. The modified 801 and 802 become much more involving, much more convincing, and much more enjoyable. In short, they are much more musical loudspeakers. Everything that the originals do so well, they will now do better.
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