PASS
SR2 Owners Manual Rev 0.2
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The “SR-2” (second Son Of Rushmore) loudspeaker is Pass
Laboratories third entry into the often-confusing world of
loudspeakers, a world fraught with claims of new technology and
brilliant technological breakthroughs. Pass Laboratories claims no
inclusion of special technology in the SR-2, only Nelson Pass’s
meticulous attention to detail, a strong commitment to using the
finest available parts and the love of experiencing the finest in
recorded music in your own environment.
The first Pass Labs loudspeaker was “Rushmore” a no compromise
system built around what we sincerely believed were the finest,
high efficiency drivers available anywhere in the world. Those
drivers were mated to four purpose built class A amplifiers,
electronic crossovers and level controls into a self contained, all
encompassing package.
Rushmore was an uncompromising product that relied on us, the
maker, having complete control over all aspects of the listening
chain with the exception of the source and material.
The Rushmore aimed for high dynamic contrast and control with
very low distortion. This was achieved with the finest quality
“strong motor” drivers intimately coupled to single-ended Class A
amplifiers. The result was a stunning display of clarity and
dynamics.
Realizing that many customers already have favorite electronics or
appreciate the opportunity to choose and substitute electronics and
cables as their preferences change. Pass Laboratories set out to
design a new family of passive speakers that would accommodate
a wide variety of customer owned electronics with as little
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compromise of the Rushmore’s acoustic characteristics as
possible.
Like Rushmore and the SR-1 the Pass Laboratories SR-2 started
with premiere examples of the loudspeaker driver makers art; the
highly regarded Nextel series of drivers from Seas of Norway. Each
SR-2 loudspeaker system contains one each of the following SEAS
loudspeaker elements;
29 mm soft dome “HEXADYM” tm magnet tweeter
18 cm midrange driver
26 cm long excursion woofer
All of these Seas drivers have very long excursion diaphragms of
carefully engineered paper and textile, low mass, under-hung voice
coils and substantial copper faraday rings in the motor assembly.
These advanced and costly design features in the Nextel drivers
assure very low, non-linear distortion and excellent transient
response.
The crossover elements are carefully selected premium domestic
units, chosen both for their sonic characteristics and technical
merit.
Each loudspeaker element and crossover in this single piece 3 way
system is hand wired, inspected and tested in the Foresthill
California factory of Pass Laboratories, assuring our meticulous
personal attention to quality control.
We at Pass Laboratories want you the listener to enjoy this hobby
in all its aspects. If you want to do nothing but listen to the music
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then we say sit back and enjoy the “SR-2” Loudspeaker for what it
does. If you want to enjoy the equipment we say sit back and enjoy
the “SR-2” for all the things it lets you do.
Unpacking
Your SR-2 system comes double boxed with each cabinet in it’s
own pack. W ithin the double box, each speaker sits in rigid foam
top and bottom trays that facilitate unpacking by a single person.
We do not suggest that you attempt to separate inner and outer
boxes.
Starting with the two large boxes, arrows on the box pointing up:
Carefully cut the tape securing the flaps on the outer box. Open
outer box and repeat for the inner box. Carefully open both of the
boxes exposing the upper and lower foam trays containing the
speakers.
At this point you should be viewing speakers in their normal upright
position. They may be unpacked inverted, but are more stable if
upright at this point.
Grasp the bottom foam tray and slide the tray, with speaker out of
the double box. Remove the top tray and cloth sock, exercising
caution so as to not damage the speakers grill covers in this
process.
Place top tray next to SR-2 cabinet. Lay speaker on its side,
balancing the cabinet squarely upon the top tray, cushioned and
protected against scuffing by the cloth sock. With the speaker on
it’s side, level and balanced upon the top tray remove the bottom
foam tray.
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Once the bottom tray is removed, place the SR-2 speaker cabinet
upright in the intended location. Place all packing into the now
empty boxes and save for later use.
The SR-2 speaker cabinets each have bi-wire input connectors and
it is strongly suggested that the customer bi-wire or bi-amp the
speakers with wire of their choice.
Speaker wire is a very personal preference; please discuss cable
options with your dealer if you do not already own cables that you
favor. Pass Laboratories has included a set of jumper cables to
allow temporary operation of the speakers with a single run of
speaker cable; we strongly suggest dual runs of cable.
During extended listening sessions with the SR-2 product, most
listeners sonically favor bi-wiring or bi-amping. For those so inclined
you are also free to actively bi-amp with an electronic crossover.
Active bi-amping through an electronic crossover such as the Pass
Laboratories XVR1 allows ample freedom to select separate
amplifiers of disparate gain for woofer and mid-range / tweeter. If
you intend to use the electronic crossover option, please contact
the factory for suggested crossover settings.
If you are using the preferred method of bi-wiring with two pairs of
speaker cables from the power amplifier, then you must remove the
supplied jumper wire. Failure to remove the jumper wire when biwiring or bi-amping places your amplifiers at risk.
Please keep in mind that the speaker cabinets are polarity
sensitive. The positive speaker terminals on both pairs of speakers
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need to attach to the positive terminals of the power-amplifier. The
negative speaker terminals on both pairs of speakers need to
attach to the negative terminals of the amplifier. Maintaining proper
signal polarity is critical with all bi-wired speakers. Failure to
maintain consistent polarity between the speakers and amplifier will
be cause all manner of ills from collapsed and diffuse soundstage
to greatly marginalized frequency response. If bi-amping with a
combination of inverting and non inverting power amplifiers then
take care to wire speakers in correct acoustic rather than correct
electrical polarity. (NOTE: Pass Laboratories amplifiers historically
are all non-inverting designs.)
Position and adjustment
It is difficult to provide absolute instructions for speaker placement;
but we can give suggestion as to good starting points. Optimal
results with the SR-2 as with most speakers are frequently
achieved with subtle changes of physical location.
Rule of the first however is that the room in which you listen is
perhaps the most significant of all audio components in the
reproduction chain. Speakers can be made to work satisfactorily in
poor sounding rooms, but it is much easier to achieve success in
an acoustically correct room.
The ideal room is neither overly reflective nor overly absorptive. In
a good sounding room, the absorptive elements tend to be at
reflection points of the sidewalls, floor, ceiling and space behind the
speaker. High ceilings or at least absorptive ceilings lend
themselves to more natural sounding spaces. Reflective floors,
while not ideal are less disruptive typically than highly reflective
ceilings.
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Diffusion generally is a good thing and excellent listening rooms
typically have diffusion in abundance. Great sounding rooms are
either large enough or absorptive enough to discourage strong
standing waves in the listening area. Good sounding rooms that
present a proper spatial image tend to be very symmetrical in
layout, left to right.
Under these idyllic room conditions speaker placement is frequently
a simple task. In an idyllic world the speakers would be well out in
the room, typically about 1/3 the distance of the rooms front to back
dimension. The listener would be at mid point in the room or
slightly to the rear of mid-point. The listener and the speakers
would form an equilateral triangle, such that the distance speaker to
speaker would be identical to the distance from either speaker to
listener. The distance from speaker to sidewall would be unequal
to the distance from the speaker to the back wall. To solidify the
acoustic image placement in stereo or multi-channel recordings at
the listening position the speakers will typically be toed in slightly
toward the listening position, rather than square with the rear and
sidewalls. The tweeter height of the speaker will be either at the
same height as the listener’s ear or in some way angled as to
achieve an equivalent result. The SR-2 cabinets have adjustable
feet, front and rear to optimize apparent driver height.
Lucky are the very few listeners who have well placed equipment in
a well-engineered dedicated listening space either by design or
happenstance. For the rest of us we have the Pass Laboratories
SR-2. The Pass Laboratories SR-2 Loudspeaker was built to
address less than perfect rooms and less than perfect speaker
placement.
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Of primary concern was a speaker that would be spectrally
balanced throughout the room rather than only in a very narrow and
defined “sweet spot”. The SR-2 was specifically built to those
parameters.
Once the speaker position and cabinet tilt is optimized for apparent
tweeter height the listener will need to adjust the level controls for
optimal results. In a symmetrical room, the adjustments for left and
right cabinet would be identical, asymmetrical rooms may require
disparate settings of level controls or left and right speakers.
Optimal level settings will be arrived at only by careful listenin g to a
variety of source material while making small adjustments. Avoid
setting that enhance only one select recording
On the rear of the SR-2 cabinets are 2 level controls. One level
control on the woofer and one level control on the tweeter. All
controls are 3 position switches that select fixed values. Mid
position is considered “Normal”, UP (clockwise) increases the level
of the drivers associated with a control. DOWN (counter-clockwise)
decreases the level of the drivers associated with a control.
Conditions indicated clearly at each switch by + /- silkscreen logo.
The level control on the woofer controls the lower bass and midbass level in the room. This control should be adjusted to optimize
bass in room while minimizing undesirable bloom and boom of low
frequencies.
The upper of the two level switches, selects one of three tweeter
levels. Mid position typically for neutral rooms, up or clockwise for
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rooms which are otherwise lacking in high frequency and down or
counter-clockwise for rooms which tend to sound too bright.
If the listening room allows the listener to be directly on axis with
the drivers and the room is neutral in character then the most likely
setting of this control will be either the mid position or perhaps the
clockwise or lower position. Rooms that require the listener to sit
off axis to the speakers and rooms that have a surfeit of absorptive
surfaces frequently require this control be in the up or
counterclockwise position. Rooms that sound bright and those with
a multitude of hard reflective surfaces typically require this control
be set in the down or clockwise position.
The suggested settings are just that… and nothing more. There is
no substitute for listening and personal judgment. We encourage
users of this product to experiment with level settings and fine
movements of speaker position until the most accurate or pleasant
combination of spectral balance and soundstage are achieved.
Specifications
Passive 3-way design, bi-amp enabled
Impedance: 6 ohms
Sensitivity: 86 dB / watt / meter
Floor space required: 16-1/2 inches wide x 24 inches deep
Overall height: 43 inches
Shipping weight 165 lbs each
And ETC.
We thank you for your confidence, and hope that you enjoy it for
many years.
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If you have any questions or comments, please don’t hesitate to
contact us.
service@passlabs.com
www.passlabs.com
Tel (530) 367-3690
Fax (530) 367-2193
Pass Labs
P.O. Box 219
24449 Foresthill Rd.
Foresthill, CA 95631
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