Velodyne Servo 1200 User manual

Vel od yne
OWNER'S MANUAL
Ser vo 1200
Subwo ofer System

SAFETY INSTRUCTIONS
f (LEtUlle $IIIICK
00 II!lT OPtN
A
CAUTION: To re duce the risk of electric shock, do not remove cover (or back), No user-serviceable parts inside. Reier
servicing 10 qualified service personnel.
The lightning flash with arrowhead svmbol. with in an equilateral triangle. is intended to alert the user to the presence 01
uninsulale d "dangerous voltage" within the product's enclosure that may be of su ffi cient magnitude to constl!ute a risk of
electric shock to persons.
The exclamation point within an equilalerallriangle is intended to alert the user 10 the presence of important operating and
mainte
nance (servicing) Instructions in the literature accompanying the appliance.
1, Aead Instructions- AUthe safety and operating instructions should be re ad before the appliance Is operated.
2. Retain Instructions -
The sale ty and operating Instructions should be re la ined for fu tu re relerence.
3. Heed
Warnings- All warnings on the appliance and in the operating i ns truclions should be adhered to.
4. Follow Inslructions - A
ll operating and use instructions should be followed.
5. W ater and Moisture - The appliance should not be used near w ater -for example. near a bathtub. w aS hbow l, kitchen
si
nk . laundry lub . in a weI basement. or near a sWimming pool. and the like.
6. Carls and Siands -The appliance should be used only with a cart or stand that is recommended by Ihe manufactUrer.
7. Wall
or Ceiling Mou nllng - The appliance shou ld be mounted to a wall or cell1rtg only as recommended by the
manufacturer.
8. Ventilation -The appliance
shoU ld be situated so thai !Is locallon or poSition does nol Interfere Wllh lis proper ventilation.
For example. the appliance should not be situaled on a bed. sofa. rug,
or similar surface that may block the ventilation
openings; or, placed
in a bUilt-in installation. such as a bookcase or cabinellhat may impede the flow of air through tl1e
ventilation openings .
9.
Heat- The appliance should be situated away from heal sources such as radiators. heat registers. stoves. or ot ef
ap pliances that produce heal.
10. Power Sources -The appliance should be connected to a power supply only of t he type described in the operating
instructions
or as mar ked on the appliance.
11 . Power·Cord Protecti on -Power-supply cords srould be routed so that they are not likely to be walked on or pinched by
items placed upon
or against them, paying particular attention to cords at plugs, convenience receptacles. and the point
where Ihey exit from the applia
nce .
12. Cleaning -The app liance should be cleaned only as recommended by the manufacturer.
13_ Nonu se Periods -The power cord of the appliance should be unplugged from the oulle! when left unused for a long
period of time.
14.
Object and Liquid Entry -Care should be taken so fhat objects do not fall and li quids are not sp illed into the enclosure
through openings.
15 . Damage Requinng Service -The applian ce should be serviced by qualified service personnel w hen :
a. The power-supply cord
or tne plug has been damaged ; or
b. Ob jects have fallen, or liquid has been spilled into the appliance: or
c. The appliance has been exposed 10 rain; or
d. The appliance does no! appear to operate normally or exhibits a marked Change Irl performance; or
e.
The appliance has been dropped, or the enclosure damaged.
16. Servicing - The user should not attempt to service the appliance beyond that described In the operat ing instructions.
All other servicing should be referred 10 qualified service persoflflel.

For Y ou r Re cord s:
Serial Number_ _ _ _ ________ _
Date of Purchase
______ _ ____ _
Name of Store ____________ _
OWNER'S MANUAL
VELODYNE SERVO 1200 SUBWOOFER SYSTEM
Congratulations on your purchase of a Velodyne Servo 1200 Subwoofer System. This system represents the
state of the art
in accurate bass reproduction. Read and follow the instructions below to insure safe and proper
system operation. Save this manual for future reference.
Warni
ng : To prevent fire or shock hazard, do not expose this equipment to rain or
moisture. To avoid electrical shock do not open speaker enclosure or amp chassis
cover. Please observe all warnings on the equipment itself. There are no user
serviceable parts inside. Please refer all service questions to your authorized
Velodyne dealer.
Prior
to installa tion : Please unpack the system ca refully. Remove all s ta ples used to seal the carton as they can
scratch the cabinet. Please save the carton and all packaging materials for future use. Record the serial number
in t he space provided above and both locations on the warranty card for future reference.
INSTALLATION
Your new Servo 1200 subwoofer system provides for a number 01 installation options. Read all the installation in -
formation below in order to determine which installation option is best tor your system. Rememberto perform all
installation procedures with system power turned off.
Input s, The Servo t200 is equipped with both speaker-level and line-level ster eo inputs. Use the LINE IN jacks
when connecting y
ou r subwoofer to a pre-amp, signal processor .o r line-level crossover. The FROM AMPLIFI ER
jacks connect directly to the speaker outputs of your integrated amplif ie r or receiver. Your amplifier section will
notice no additional loading effects when you use these in puts because of their high im pedance.
NOTE: Do nol use both line and speaker level jacks simultaneously.
High Pass Crossove
r. Because your satellite speakers cannot reproduce bass as accurately as the Servo 1200,
optimum system performance is attained by roll in g off th e low end response of your satellites. The Servo 1200 is
equipped wi th a high pass crossover lOr this purpose. To use t he crossover. simp ly drive your power am plifier or
satellites from the Servo 1200's outputs.
Interc
onn ec tio n Cables. When installing y ou r Servo 1200 us i ng FROM AMPLIFIER and TO SPEAKERS (as in
Figure 1) run the same quality speaker cable to your subwoofer as you do to your satellites. If the speaker level
cables to your Servo 1200 w ill not be driving any satellites, then a medium guage "zip cord ~ is sufficient to supply
the subwoofer alone.
Une level cables should b.e standard shielded phono cables. Always keep leads between you r pre-amp and
power amplifier as short
as pOSSible. If necessary. cables to t he subwoofer unit alone can be quite long (s ee
Figure 3).

IN STALLATION OF SERVO 1200 USING FROM AMPLIFIER INPUTS
Figure 1 shows how to connect your Servo 1200 to a receiver or integrated amplifier. When using the speaker
level terminal
s, note the right and left channel designations above t he terminals. Red speaker jacks are pos itive,
black speaker jacks are negative (common
).
SATELLITE SPEAKERS
AMP LI FIER OR RECEIVER RI
GHT
LEFT
R L
, --. + -
II '? '?
J U
I
M FROM
AMPLIFIER
qrrlp
II
J
117 VA C
50 1 60 HZ
2AMPS MAX
LINE
. ""'
0,0
0,0
NOTE:
+ -
lOW PASS
CROSSO VER
70
tr
" '"
'00
"
RED TER MINALS ARE
POSITivE. SLACK
TERMI NA LS AR E NEGA TIVE
S ER VO 12 00
REAR PANEL
Figure 1: Installation Us in g FROM AMPLIFIER Inputs
Caution: To avoid damage to your main a mpl if ie r be sure to make all spe aker
connections from RED (positive) to RED and from BLACK (negative) to BLACK. Be
surethai all connectionsaretight, and that there arenoloosestr ands or frayed wires.
- 2 -

I NS TA LL ATION OF SE RVO 1200 USI NG LINE INPUTS
Figure 2 shows how to install your Servo 1200 between a pre-amplifier and power amplifier. If you are con-
necting to the monaural subwoofer output of a surround sound decoder, then run a single phon~ ca ble from the
decoder's
sub oulto either the right or left LINE IN jack on the Servo 1200. Leave the unused input a·nd both
outputs disconnected.
PRE-AMPLIFIER POWER AMP LI FIER
MAIN OUTPUTS R L
eQ 0 . -
~~
~
R 0
~
~
I I I
LOW PASS
FROM LINE.
CROSSOVER
TO SPEAKERS AMPUFIER
r--
"
IAlGI-HI I LEn J
f';r~~ ':
IN OUT
j101~IOj
o 0 0 0
\B eG
tr
~
00 '"
' 00
'"
111 VAC
50160 HZ
lAMPS MA X
F ig ure 2: In sta ll ation Us in g LI NE Inputs
-3 -
SATEL LI TE SPEAKERS
RIGHT
,
11 99
LEFT
, -
SERVO 1200
RE AR PANEL

IN STALLATION OF S ER VO 1200
USING EXTERNAL CROSSOVER
Velodyne offers an optional external high pass crossover unit (part no. 80- 111 FIN) for those who wish to use
LINE IN/OUT but must locate their Servo 1200 away from system electronics. By installing the external crossover
near your electronics, all leads between your pre-amp and power amp are kepi as short as possible. High fre-
quency integrity is thereby maintained while enabling remote subwoofer installation (see Figure 3) .
The external crossover operates at line level only an d is characteristically similar to the high pass crossover
built into the Servo 1200.
PRE·AMP LI FIER POWER AMP
LI FIER
SOURCE INPUTS OUTPUTS INPUTS R L
..
0 000
, , H
~
0000
~
0
I
t-- shon leads ----+
I rL
' N," ' ",G"? ws", EXTERNAL CROSSOV ER
L- -o l E FT G
, ~"' G- l
f----- long leads
LOW PA SS
FROM
LI NE CROSSOVER
TOS PEAKERS A MP UFIER 1
.--
"
Ifl lGHT l1 LE FT I
r.;;:;l r.;;;::;;;I IN OIJT
,
~ 4<> ,0
~
1'1'1'1' 1
000 0; ~
00 ~
'00
"
117 VAC
""" "
2 AM PS MAX
Figure 3: In stallation With Optional EXTERNAL CROSSOVER
- 4 -
}
TO SATELLITE
SPEAKERS
S ER VO 1200
REAR PANEL

INSTA LL ATION OF TWO SERVO 12005 AS A STEREO PA IR
Although a single Servo 1200 will improve the performance of any audio system, many listeners demand the
additional pow
er and effect of stereo Servo 12005. Figure 4 shows stereo connection using speaker level inputs.
Note that one pair of input/oulpu
ll erminals remain unused on each unit. Stereo connections can also be made
with the line level
in puts.
SERVO 1200
(RIGHT)
'"0
TOS PEA~EAS
I A"'~; . ~ I
I A l(;t ll l~
"
"'
PS MA X
o 0
\ • -
t<>Gi
RIGHT SATELLITE
SPEAKER
o 0
I
RECEI VE R OR AMPLIFIER
LI NE
~ ow PASS
CROSSOVER
"
~
0 , 0
~
~ .
0 , 0 '"
..
A l
1;';& 1 ;1
I I
I
., l VA C
.... "
2 AM F'S M AA
10 SPE,*, ERS
~rw;tl r.
o 0
V
,/'
)
\ .-
§l
LEFT SATElliTE
SPEAKEA
Fi gure 4: Stereo SERVO 12005, Speaker Level
- 5-
I SERVO 1200
(LEFT)
LOW PASS
"' ~Efl
U"'
CROSSOVER
"
, =
~
0 , 0
rr
o 0 M •
0,0
'"
..
Non ,
RE D TEAM'NAlS ARE
POS IT IVE . Bl..AC II;
TERMlNALS"'R £C NEGATIVE

PLACEMENT
The Servo 1200 operates primar il y al frequencies below 85 Hz . These fr equencies are essentially non-dIrec-
tional such that you may place the subwoofer almost anywhere without degrading the stereo imaging characteris-
tics
of your main speakers.
When using a pair of Servo 12005 in stereo, it is preferable to place each subwoofer adjacenllo the satellite
of the same channel.
Keep in mind thaI frequency response and oulputlevel can be greatly influenced by placement, depending on
the acoustic properties of the listening room. Typ ically IheServo 1200 will sound louder next to a wall or in a
corner:
Ca u tio n: The Servo 1200 amplifier is buill lh to the woofer cabinet. Do not place
cabinet next to sources of heat such as furnace registers, etc. The power cord
should be routed in such a way that it will not
be walked on. pinched, or com-
pressed.
CONTROLS
The control panel on the front of your Servo 1200 includes a power switch, a power-on indicator lamp, and a
level control.
The power switch is a push-on/push-off type
and is located in the upper lett position of the pane l. The green
indicator lamp
comes on when the Servo 1200 is switched on and properly powered.
The subwoofer level control knob (lower right position)
is used to adjust the volume level of bass in formation
in relation
to the midrange and treble frequencies. We recommend that you begin listening with the level set at the
point midway between
MAXIMUM (funy clockwise) and MINIMUM (funy counter-clockwise). Play several selec-
tions of music and vary the subwoofer level unfll the bass matches the mids and highs to your satisfaction. Once
you set the subwoofer level, you simply use your system's main vol ume control and the bass proportion will
remain consistent.
The
LOW PASS crossover control is located on Ihe rear panel. II allows you 10 adjusllhe upper limit of the
Servo 1200's frequency response. For example, with Ihe crossover set at 60 Hz , the subwoofer begins rolling off
above this frequency.
Us ing this control you may match the Vetodyne precisely to your main speaker s. If you are
using very small bookshelf speakers you
may wish to raise the tow pass as high as 100Hz. If you own large full
range loudspeakers. you may
fi nd a lower setting more appropriate.
By fine tuning the level and crossover controls, you can create a seamles blend between the Servo 1200 and
your main speakers, with bass response and output tailored to your listening room and personal preference.
- 6-

CARE OF YOUR SUBWOOFER
We recommend usIng a clean damp cloth for cleaning the cabinet. Never use detergents or abrasives on your
Servo 1200.
The Servo 1200 may be left on continuously without fear of long-term adverse effects. We do recommend that
you turn off the unit during extended periods of nonuse.
PROTECTION CIRCUITRY
Your Servo 1200 is equ ipp ed wi th a spedal ciruil designed to protect the unit from damage. Either 01 the two·
condilions below will power the unlt down and keep it all lor 5 seconds after the fault is corrected.
1) "there is a significant drop in the line voltage.
2) If there is an input signal which momentarily exceeds the dynamic range of the unit.
TROUBLESHOOTING / SERVICE
Before seeking service for your Servo 1200, please re-check all system and power connections, Also con-
sider the protection circuit described above; you may only need to turn the volume down slightly.
II you determine that your unit requir
es service, then please contact your local Velodyne dealeL
The following conditions always require service by qualified personnel:
t) If the power cord is damaged
2) If the unit does not appear to operate normally or exhibits a marked change in performance
3) If the unit has been exposed to water
VELODYNE HGS SYSTEM
Velodyne's prime focus is in providing low distortion loudspeaker systems that impress the dedicated audio-
phile
as well as the casual listener. Velodyne developed its patented High Gain Servo (HGS) system to bring
nonlinear distortion down to unprecedented levels on its UlO-15 and ULD-18 high performance subwoolers. Yo ur
new Servo Series Subwoofer uses th is same HGS technology to reproduce the music you enjoy without the
excessive nonlinear distoritons that plague conventional loudspeaker desi
gns .
The Problem of Distortion
Nonlinear distortion is defined as any form of distortion that moves energy from one portion of the audio
frequency spectrum to another. When a single tone is applied to a nonlinear system, the result is harmonic
d
is tortion, in which some of the energy leaves the system at fnteger multiples of the onginal Input frequency.
When multiple tones are applied to the same system, intermodulation tones are produced, usually
as simple
combinations of the input frequenci es , Le., sums and differences of integer multiples of the applied tones. In
general. 3% nonlinear distortion is considered a reasonably small amount. This means that 3% of Ihe lotal energy
leaving a loudspeaker is at frequencies other than the intended pure tone applied to the input. Our tests, however,
indicate that about 0.5% nonlinear distortion at
normallislening levels must be achieved before the average
listener is truly affected by an improvement in bass response.
In the reproduction of deep bass notes, loudspeakers suffer from a "double-whammy" when it comes to
nonlinear distortion. First, most loudspeakers have much more than even 3% THD (Total Harmonic Distortion) al
-1-

low frequencies. Even at 1 watt drive levels, many loudspeakers have 8 to 10% THO at 40 Hz. With the 50 watt
drive levels needed to produce realistic bass intensity, these distortion figures rise to
as tonishing levels, Second,
the distortion products produced by a nonlinear woofer are much easier to hear than
is the fundamental fre -
quency. Consider a speaker driven at 30 Hz with 5% 3rd harmonic distortion. If the 30 Hz tone is 90 dB SPL
(Sound Pressure Level), equating to about 5 walls into a typical woofer, the 3rd harmonic, at 90 Hz. would
be
down 26 dB. or at 64 dB SPL. However, humans are more than 10 times as sensitive to sound at 90 Hz than at 30
Hz. The nonlinear distortion produced by a woofer must be weighted by the sensitivity function of the human ear.
Wilen this is done, it becomes clear that even a small percentage of harmonic distortion is unacceptable in a bass
driver.
It is also clear that high·order (3rd. 4th, 5th, etc.) harmonic distortion products are more serious than are
2nd harmonic distortion products. These studies have led to the conclusion that 0.5%
is the maximum tolerable
amount of nonlinear distortion for a bass driver. and the less distortion the driver produces. the more capable it is
of accurately reproducing live sounds.
Since most woofers today have at least 10% THO when 0.5% is the maximum tolerated, minor improvements
in woofer technology are essentially ineffective. Servo Series Subwoofers have about 90 times less nonlinearity
Ihan a lypi
call0 inch bookshelf speaker. They have aboul3times less distortion due to their greater size and
power handling capability, and about
30 limes less distortion due to the Servo feedback loop. The improvement is
even greater if one considers except io nally loud and deep tones such as organ pedal notes.
An interesting result of this reduced distortion is that much of the bass, when played over a servo Series
Subwoofer, seems to actually be reduced. The truth, of course, is thai the "missing" bass was never really there
on the source material. and was never intended
10 be played by the artist. Distortion products introduced by
conventional woofers actually make the entire bass spectrum sound louder.
Our Solution
The Velodyne Servo Series Subwoofer System produces sound in the same manner as any conventional
loudspeaker: a cone-shaped piston
is forced to move by means of a linear motor composed of a coil situated
between the poles of a very strong permanent magnet.
In the Servo Series, however, this linear motor IS a servo-
motor. meaning thai the motor is linked to the power amplifier as part of a control system. The basis for the control
action
is the signal obtained from an accelerometer which is rigidly fastened to the vOice Call. The strategy of
continuously monitoring the cone motion, and using this information
as the basis for the corrective action, is called
motional feedback. This feedback technique is illustrated in the system block diagram, Figure 5.
The signal into the system is a time varying voltage which is an exact analog of the desired acoustic output
from the loudspeaker. The accelerometer output contains sufficient information 10 deduce the actual acoustical
output of the woofer. The servo circuitry compares almost instantaneously how well the acoustic output matches
the command signal coming
in . If and wnen there is a deviation, the servo circuitry modifies the drive signal to the
amplifier so that the acoustic output from the speaker
is a true representation of the input.
In conventional loudspeakers, the drive signal into the speaker is virtually free from distorti on but the
speaker's acoustical output may be highly distorted.
In Servo Series Subwoofers, the speaker coil drive signal is
often highly distorted, or actually pre-distorted, in exactly such a way that the acoustical output from the speaker is
free tram distortion. Motional feedback has been used previously
in an attempt 10 make small woofers sound like
larger, more powerful ones. At Velodyne, the use of motional feedback is applied to make what is already a large
and powerful woofer achieve a level of performance that has never before been reached in a home entertainment
product.
HGS System Components
(Refer to Figure 5)
High a nd Low Pa ss Cr oss ove rs receive the incoming audio signals from your system pre-amp or power amp.
Frequencies above 85
Hz are diverted to your power amplifier while frequencies from the right and left channels
below 40 to 100 Hz (depending on lo w pass crossover setting) are summed to monaural and passed on to
subsequent stages
in the subwoofer.
Loop / Control Stag e. Incoming bass signals pass through a variable gain amplification stage designed to protect
the subwoofer from being overdriven (see Supporting Circuits below
). Wi th a bit of added filtering, the bass signal
is now ready to be compared with the feedback signal of the accelerometer. A composite signal is created which
compensates
for erroneous movement of the cone. - R-

I NPUT FAOM
HOST SYSTEM
I
SUPPO RTING CI RC UI TRY
I
PRE - AMPLIFIER
~ t
tl _/
~ IGH . "NO
H ~ :
t>
OW· PASS LOOP I CONTROL
- ~
~ ~~
CROSSOVERS
AMP
+
-",
HIGH-P A SS OUTPUT
C USTOM DR IVE R ACCELEROMETER
TO HOST SYSTEM
AND AM PLIfiER
POWEA AM PLIFIER
OR SPEAKERS
FE EDB A CK SIGNAL
Figure 5: Servo Series System Block Diagr am
Power Amplifi er. Tile Servo 1200's amplifiermust provide power for distortion correction as well as basIc music
reproduction.
Custom Driv
er , Although our HGS electronics play the most important role in redudng distortion, the Servo
Series driver musl be carefu
ll y engineered and constructed so as not 10 undo the work Ihal t he H GS eleClronics
have done. A large magnet and voice coil are used to improve sensitivity, the cone is specifically shaped to
reduce resonances, and ventilation ho les are used liberally to eliminate whistling no ises often associated wi th
long-travel operation (essent ial for producing low frequencies at listenable volumes).
Accele
rom eter. Perhaps the most cr itical component of the HGS system, the accelerometer measures the
motion of the cone and relays it back
to the loop circuits by means of an onboard charge amplifier and special
feedback circuitry.
S
upp o rting Circ uit s. A GAIN COMPRESSION ci rcuit evaluates the amplitude of the incomi ng bass signal. T he
gain compressor is directly linked to the control stage and can thereby limit input signal gain in or der to preve nt
amplifier clipping. If an extremely loud transient is detected, the gain compressor circuit will signal the COMPARA-
TOR circuit
to immediately shut down the subwoofer's power amplifier to r five seconds. The comparator circuit will
also shut down the power amplifier if
it detects problems with the power supply.
VE LODVNE, Servo 1200, lJLD·15, and UL D 18
are registered trademarks at Velodyne Acoustics, Inc.
Velodyne Acoustics,Inc.
1070 Commercial Street
San Jose C a., 95 11 2
( 408 ) 4 36 -06 88
- 9-

VELODYNE SERVO 1200 ™
SUBWOOFER SYSTEM SPECIFICATIONS
Type:
Power:
Stereo Input ~
Diameter:
Linear travel:
Voice COi l:
Magnet:
Cone:
Accelerometer:
High Pass:
Low Pass:
Rm sh;
Dimensions:
Volume :
Weight:
Grill:
Servo loop Gain:
Servo Loop Feedback Rate:
Maximum Distortion (25
Hz@ 104 dB):
Frequency Response:
Driver Resonant Frequency:,
Damping Facto r'
Protection;
Warranty:
Amplifier
Integrated Class AlB.
100 walts continuous RMS, 400 watts peak.
Une level sens itivity - 1 00 mV 11 OK nominal
Speaker level sensitivity - 1 volt nominal
Driver
12 inches.
~h6 " peak to peak.
Copper; 2
W' Diameter. 1 1" Length.
56 oz .
Resin impregnated fiber.
Piezo wi th integral amplifier,
Crossover
Passive, 85 Hz nominal. 6 dB per octave.
Active, Dual slope, adjustable from 40 Hz to 100 Hz.
Slope, 6 dB per octave initia l, 24 dB per octave ultimate.
Cabinet
Slack, Vinyl woodgrain
(H) 16 W
', (W) 18 1 /4", (D) 18 1 / .~ .
3000 cu. in.
601bs.
Slack Knit.
Servo
26 dB.
3500 corrections per second.
<. 5%
20 Hz low, 40 HZ - l 00 Hz high
(depending
on crossover setting).
<4 Hz
>1000
Low Voltage, Excessive Si gna l.
2 years.
Specifications ar e subJect /0 change wi/flout notice.