Bryston 10B-SUB, 10B-STD, 10B LR User Manual

10B

CROSSOVER

OWNER’S MANUAL

for Models

10B-STD, 10B-SUB & 10B-LR

INTRODUCTION:
The 10B crossover is available in three stock versions; 10B-SUB incorporating frequencies more
suitable to sub-woofer applications (40Hz to 500hz), 10B-STD which is more applicable to speakers
requiring frequency control in the mid-band and tweeter areas (70Hz to 4500Hz) and the 10B-LR,
which uses plug in resistor programming cards to set the crossover frequency. Both the 10B-SUB
and 10B-STD crossovers include a mode called Mono Low Pass (see below) which replaces the Two
Way Mono (Linkwitz-Riley) mode in older model 10B’s. The Two Way Mono mode (see below) is

retained in the 10B-LR allowing for very steep (non Linkwitz-Riley) 8th order lters.

MONO LOW PASS MODe (10B-SUB AND 10B-STD ONLy):

The 10B-STD and 10B-SUB crossovers generate a summed low pass output signal by rst summing

or adding together the left channel and right channel input signals to form a left plus right (L+R) sig­nal. If the MODE switch (located on the rear panel) is in the Mono Low Pass position then this L+R

signal is fed into both of the low pass lter sections (Left and Right) available in the 10B. As a result,

the common low pass output can be taken from either of the two low pass (LP) outputs; either left LP
out or right LP out. These outputs are designated as Left and Right for convenience only. If the low
pass output used is the one designated as the left channel, then the crossover frequency and slope

(or lter order) switches on the left side of the unit’s front panel (as viewed from the front) will control
the low pass lter parameters. Likewise, if the right channel low pass output is used, then the right
channel switches will control its lter parameters. There is no interaction between the two sets of con­trols. If one of the two low pass lters is not used, then settings of its crossover frequency and slope
switches are irrelevant and will have no affect on the performance of the other lter sections of the
crossover. The two high pass lter sections (left and right) operate independently in Mono low Pass

mode.

STeReO MODe:

As in the older versions of the 10B, the stereo mode provides two, two way crossovers wherein the
left input is fed into a separate low pass lter and a separate high pass lter, both of which are inde-

pendently adjustable from the front panel controls. Likewise, the right input signal is fed into a sepa-

rate low pass lter and a separate high pass lter, both of which are independently adjustable from
the front panel controls. All four lters have separate output connectors on the rear panel. There is no
interaction whatsoever between left and right channels or between low pass and high pass lters.

THRee WAy MONO MODe (10B-LR ONLy) :

Available only in the 10B-LR (Linkwitz-Riley lters), this mode is the same as in the older model 10B.
The four lter sections (two low pass and two high pass) of the 10B are combined to form a single
channel three way crossover providing one low pass, one mid or band pass and one high pass lter.
The mid (or band pass) lter is formed by combining the left channel high pass and the right chan­nel low pass lters into a single lter wherein the lower end of the pass band is determined by the left

channel high pass controls and the upper end of the pass band is determined by the right channel low
pass controls
Only the LEFT channel input is used in Three Way Mono mode. The left channel low pass output
provides the low pass output. The mid or band pass output is taken from the right channel low pass

output connector and the high pass is taken from the right channel high pass connector. All lter

slopes are 24dB per octave, Linkwitz-Riley alignment.

PROGRAMMING THe 10B-LR CROSSOveR:

The crossover points in the 10B-LR are set by inserting small programming boards (4 per channel)
each containing 2 resistors. See illustration “10B LINKWITZ-RILEY STEREO CROSSOVER” and on

page 7 and document “10B-FREQ-RES-TABLES.doc”

POWeR AMPLIFIeRS:

When power ampliers of different power capabilities are used, the woofers will likely be driven by
the most powerful amplier and the tweeters by the least powerful amplier since the woofers can
generally be expected to be less efcient. When power ampliers of equivalent power capabilities

are used in a bi-amped system, and when the power amps employ totally separate power supplies

for each channel (as all Bryston power ampliers do) it is desirable to place each power amplier as

close to its speaker as possible and use one channel to drive the woofer and the other to drive the
tweeter. Please note that if the power amps being used do not employ totally separate power supplies
for each channel, some envelope distortion between channels may occur since the power drawn from
the low frequency channel driving the woofer will usually be considerably greater than from the higher
frequency channel driving the tweeter.

POWeR AMPLIFIeR PLACeMeNT:

Where there is a considerable distance between the audio signal source and the speakers, it is

preferable to reduce the distance between the power ampliers and the speakers at the expense of
increasing the distance between preamp and crossover or crossover and power amplier. The low im-

pedance across the speaker lines is more likely to affect signal quality with distance than is the higher

impedance across the preamp to crossover, or crossover to power amplier cables.

BALANCeD veRSUS UNBALANCeD CABLING:

If the distance between the power amplier and crossover or crossover and preamplier is greater

than 30 feet, it may be desirable to use balanced cables to interconnect the two distant pieces of
equipment as this may reduce noise pickup. To facilitate this, the 10B crossover is available with bal­anced inputs and outputs (PRO versions) using 3 pin XLR connectors (outputs use male connectors,
inputs use female connectors). Pin 3 is the positive (non-inverted or Hot) signal, pin 2 is the negative
(inverted or neutral) signal and pin 1 is ground.

Where a long run of balanced cable is used to interconnect the preamplier to the crossover, and the
crossover is placed within a few feet of the power amplier there is no advantage in using a balanced
interconnection between the crossover and power amplier. Balanced cabling does not reduce noise;

it merely reduces the ability of the cable to pickup noise. The balanced output of a 10B Pro crossover
can easily be used as an unbalanced output by using XLR pin 3 (positive) as the HOT line and XLR
pin 1 as the ground line.
Since there is no phase inversion in the 10B, the negative XLR output pins (#2) can be used
in the same way to achieve the same effect and the output will remain un-inverted with respect to the
input. In other words, any signal that enters the negative XLR input pin (#2) will exit the negative XLR
output pin (#2) un-inverted with respect to the input. Similarly any signal that enters the positive XLR
input pin (#3) will exit the positive XLR output pin (#3) un-inverted with respect to the input. It is for

this reason that the 10B has not been changed to comply with the AES adopted XLR pin conguration

for balanced signals (pin 3 negative, pin 2 positive and pin 1 ground) and retains its original XLR pin­out of pin 3 positive, pin 2 negative and pin 1 as ground.

Note, however, that Bryston’s current production power ampliers do follow the AES conven­tion. As the above illustrations indicate, however, the 10B PRO models do not introduce any phase

inversion and thus can be used with either pin 2 hot or pin 3 hot balanced cable systems without
changing the phase relationships of the system.

CABLeS:

Bryston supplies a variety of stock audio interface cables and will supply reasonably priced semi-

custom cables (including adapter cables and cables with custom printed identication sleeves) upon

request. Bryston’s balanced cables employ double insulated, 100% shielded twisted pair cable with

24g stranded, tinned copper conductors and locking XLR connectors with metal shells and gold plat­ed contacts. Unbalanced cables use single conductor shielded co-axial cable with gold plated male

phono (RCA) plugs in metal shells.