The 800 Series' Dilemma

The B&W 801 was originally designed as a cost-no-object, no-compromise studio monitor1. The design team set performance goals that were dictated by studio needs, and developed within those parameters the loudspeaker that has become the most successful studio monitor in history.

Even though many 801's made their way into the homes of audiophiles, incarnations of the loudspeaker up to and including the Matrix 2 were manufactured with studio performance the foremost concern. It was not until the Anniversary - Limited Edition and Series 3 that the needs of the audiophile were considered, and even then only partially addressed.

Requirements of the studio dictated that several performance compromises were made in producing the B&W 801. The foremost requirement was dependability, and to address this the protection circuitry was developed. This circuitry is present in the signal path at all times, and its presence is clearly audible, yet for most audiophiles the circuitry rarely (if ever) comes into play.

The second compromise was mobility. The monitors had to be easily relocated, hence they were supplied on casters and the crossover network was constructed on a small circuit board located beneath the woofer cabinet. This also meant the crossover components had to be as small as possible, and be located on the board along with the protection circuitry. Hence, the B&W crossover is constructed of small ferrite cored inductors and electrolytic capacitors, instead of the better sounding but less space-effective components. The space limitation also lead to the inductor field interactions and current limitations well documented elsewhere2.

Our approach to the B&W 801 and 802 is from a loudspeaker designer's point of view. Rather than work to improve the performance of the existing systems, we eliminated the studio from the design process. This gave us the freedom to develop our crossover networks without any size, space, or weight constraints. The result is the North Creek Complete Crossovers, which are complete replacements of the original units.

The North Creek Complete Crossovers for the B&W 801 and 802 yield improvements in every aspect of the original. Sound stage, focus, impact, detail, clarity; these are all enhanced. The low end becomes deeper, tighter, more textured, and more controlled. The midrange purity rivals any other loudspeaker regardless of technology. The top end is smooth, sweet and extended without a hint of grain. The trade off is size, as the North Creek Crossovers must be externally located in dedicated cabinets and require significant floor space.

The B&W 801 and 802, with the North Creek Complete Crossovers, become two of the most musical transducers ever made.

1) New developments in loudspeaker system design- the B&W 801 monitor, John Bowers, presented by G. J. Adams at the Consumer Electronics Show Chicago, June, 1979.

2) Audio Magazine, November, 1990 review of the B&W 801 Series 2.

The Complete Crossovers

for the B&W 801 and 802

The North Creek Music Systems Complete Passive Crossovers are complete replacements of the factory units. Every detail of the original designs have been analyzed and re-evaluated from the audiophile's point of view, and the resulting replacement networks, completely redesigned for 1996 and manufactured in our own facilities, are no-compromise products that bring these loudspeakers into an entirely new performance envelope.

The North Creek Crossovers consists of three physically and electrically independent networks per channel, one for each driver. These networks are constructed from 1% hand matched components where the matching is done on a component level before the subassemblies are constructed. Matching is also verified during final testing. The maximum variation in left/right networks is less than ±1%, five times tighter than original production.

The North Creek Networks are completely hard wired. No circuit board and foil conduction paths are used; rather, solid copper bus bar or inductor leads make main connections. This construction method results in a minimum of connections both in and out of the signal path, maintaining signal integrity.

Global star grounding is also used throughout the networks. Each element tied to ground has a unique signal path directly to the negative binding post. As the networks must also be bi-wired, this approach results in separate low and mid/high ground paths all the way to the amplifier terminals. This topology completely eliminates ground crosstalk between low and mid/high portions of the network.

In the case of the B&W 801, the North Creek Crossover may also be ordered with the woofer impedance compensation circuitry provided in the Series 2 and Anniversary Edition, but eliminated in the Series 3. This circuitry allows for 2dB of adjustment in mid-bass level. Those who bi-amp or have mid-sized listening rooms may find this level of adjustment invaluable. The circuitry may be added at a later date and can also be added to existing Series III's.

Lastly, the networks are provided in separate, external cabinets measuring 6" x 12½" x 21", one per channel. Removal of the crossover from the loudspeaker cabinet isolates the components from structure-born vibration, and the enclosures are spiked to the floor to provide a solid mechanical ground. The cabinets are handsomely finished in brushed matt black, and solid 3/4" hardwood to match the main loudspeaker is optional. Each network requires over 2500 feet of copper and weighs an average of 40 pounds per cabinet.

Each enclosure is provided with a dedicated cable to link the crossover to the driver cabinet. The cable is terminated with high quality, gold-plated spades. These are connected to a replacement back cup fitted with the mating mil-spec, gold-plated binding posts. Color-coded wiring is also provided to connect to the 801 internal wiring inside of the cabinet base.

The majority of raw materials used throughout the networks are from our regular inventory, and their complete descriptions may be found in our "Loudspeaker Products" catalog. These include 12 and 10 AWG Music Coilå air core inductors, the legendary Crescendo film and foil capacitors, high voltage, high frequency polypropylene film capacitors manufactured for us by Sprague-Dearborn, and mil-spec, 1% tolerance Ohmite power resistors. All North Creek components have been selected purely by subjective evaluation for their enduring quality and sonic excellence. In most cases, these components were developed for U.S. Military applications and are Mil-Spec rated. Lastly, the crossovers are 100% made in the USA from US sourced materials.

The North Creek Music Systems Complete Passive Crossover Replacements for the B&W 801 and 802 are not redesigns of the original crossovers. The circuit topology and component values are identical to the original Series III specifications, and the essential character of the loudspeakers remain unchanged.

The North Creek Crossovers are completely new crossovers, manufactured with the finest passive components and representing a no-compromise approach to passive crossover design and manufacture. These are the ultimate upgrades for the B&W 801 and 802.

B&W incorporated the protection circuitry into the Series II crossover to prevent premature failure of the driver units, reducing studio down-time and the recurring need for driver replacements. This circuitry was not developed for the audiophile, however, and the relays in the signal path severely compromise the signal integrity. Most performance upgrades, including those provided by B&W, begin with removal of this circuitry. Our Complete Passive Crossover replacement eliminates all of the protection circuitry. This is absolutely necessary to achieve the ultimate performance from the loudspeaker. However, elimination of this circuitry also makes the drive units more susceptible to failure. Therefore, those considering the Complete Passive Crossover Replacement should seriously evaluate their listening habits.

The single rule with protection circuitry is: if you use it, you need it.

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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Our Guarantee

North Creek Music Systems guarantees that you will be 100% satisfied with your crossover. If you are not completely satisfied, for any reason whatsoever, please return them within 45 days from date of installation. We will fully refund your original charges.

Warranty Information

The North Creek Crossovers for the B&W 801 and 802 are warranteed for three years from date of purchase. For that period we will, at our option, repair or replace factory defective components. North Creek Music Systems' liability is limited only to replacement of defective parts. No other liabilities or obligations are written or implied.

B&W, 801, 802Ø and Matrix are trademarks of B&W Loudspeakers.

Music Coil, Ultra-CAP, "Design Without Compromise," and "Simply Better Technology" are trademarks of North Creek Music Systems.

This publication is copyright © June 1995 , June 1997, December 2005 by North Creek Music Systems.