REL Acoustics Speaker Stampede User Guide

USER MANUAL  
STAMPEDE  
AND  
STRATA 5  
REL Acoustics Limited  
North Road, Bridgend Industrial Estate  
Bridgend, CF31 3TP  
Great Britain  
Telephone: +44 (0) 1 656 768 777  
Fax: +44 (0) 1 656 766 093  
 
REL Acoustics ST 5 User Manual  
WELCOME  
Thank you for buying a REL “ST” range Sub-Bass system. This manual contains important  
safety information as well as helpful advice and should be carefully studied before integrating  
the sub-bass system with your sound system.  
The new ‘ST’ range of REL sub-bass systems represents a radical advance in technical  
design. The adjustment of level, phase and crossover is achieved through new  
microprocessor controlled circuitry, eliminating the need for multiple control knobs. Each  
model offers the remote control of all calibration adjustments, enabling the user to set-up the  
sub-bass system easily and more accurately from the listening position. All these settings can  
be saved into memory and recalled at any time. Most adjustments are available from the  
remote, but a few adjustments that are normally only set on installation are only available  
from the front panel.  
Reliability, quality of construction and performance of REL products is maintained and  
enhanced by the innovative design of the latest ‘ST’ series of REL sub-bass systems.  
STAMPEDE AND STRATA 5  
Stampede and Strata 5 are designed as closed box systems. For their cabinet volume and  
drive unit, this arrangement offers the best compromise between extension and power  
handling. With smaller cabinets, the addition of a port to make it a reflex design can result in  
excessive port noise, which manifests itself as ‘chuffing’ when very low frequencies, such as  
organ pedal notes, are reproduced. Worse, a small cabinet will not extend down as deeply as  
its closed box alternative.  
The cabinets are manufactured from 30 mm thick MDF (Medium Density Fibreboard). This is  
the material of choice when the very highest quality is demanded. There can be no substitute  
for weight and density in the quest for accurate low frequency reproduction.  
Stampede and Strata 5 offer microprocessor control of all functions, either via the remote  
control or the encoder on the front control panel. Remote control makes it easier for the user  
to set-up the sub-bass system from the listening position.  
For optimum performance we believe the electronics, cabinet and the drive unit should all be  
designed to work together.  
All REL amplifiers are fully DC coupled to avoid phase shifts and compromises in their  
performance. The line level and filter stages are fully regulated to ensure total isolation from  
the power amp stages. The filter stages are unique, bespoke designs which utilise the highest  
quality components. The capacitors are high quality nitrogen filled polystyrene types of 1%  
very close tolerance and indefinite life. The use of very close tolerance components also  
ensures consistency of performance throughout the life of each model. Although digital  
control is used, the audio signals only pass through analog circuits, thus ensuring no digital  
hash is added to the signal.  
Great care is taken to star-earth the circuit boards to maximise sound quality.  
There is further filtering of the higher frequencies to ensure optimum performance at all  
settings of the ABC (Active Bass Controller). The built-in power amplifier is uses ultra-rugged  
audio grade MOSFET output devices. High quality smoothing capacitors offer long life with  
very low ESR (Equivalent Series Resistance). The transformers are ultra-quiet audio quality  
low-loss toroids, specially manufactured to REL’s strict specifications. Great care has been  
taken to deliberately over-engineer all REL products to ensure unparalleled reliability.  
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REL Acoustics ST 5 User Manual  
MAIN FEATURES OF THE NEW ‘ST’ SERIES  
1.  
2.  
3.  
Microprocessor control with memory for all functions  
Dedicated digital readout for all functions  
All components are of superior quality in order to achieve long life and long term  
consistency of sound quality  
4.  
5.  
6.  
All cabinets made from 30mm thick MDF  
Superior wood veneer finishes are available for all models  
Set-Safe® circuitry ensures a high standard of protection if the sub-bass system is  
overloaded  
IMPORTANT SAFEGUARDS  
1. Read all of these instructions.  
2. Save these instructions for future use.  
3. Unplug the sub-bass system from the wall socket before cleaning with a damp cloth. Do  
not use liquid or aerosol cleaners.  
4. Do not use near water.  
5. Always position the sub-bass system on the floor.  
6. The sub-bass system should only be connected to the power source indicated on the  
panel of the amplifier.  
7. Only use the power cord supplied or one of similar quality and construction.  
8. Do not allow anything to rest on the power cord. Position the power cord so that it cannot  
be stepped upon.  
9. For added protection during a lightning storm, or for long periods of system inactivity,  
unplug the sub-bass system from the wall socket.  
10. Avoid spilling any kind of liquid on the sub-bass system.  
11. Do not attempt to service the sub-bass system yourself. In removing the amplifier, you  
may be exposed to dangerous voltages. Refer all servicing to your dealer.  
12. Unplug the sub-bass system from the wall socket and refer to your dealer under the  
following conditions:  
a. When the power cord or plug is damaged.  
b. If liquid has been spilled on the system.  
c. If the system does not operate properly after following the operating instructions.  
d. If the system has been dropped and damaged.  
e. When the system exhibits a profound change in performance.  
WARNING  
This sub-bass system is heavy. To avoid risk of injury, take care when handling.  
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REL Acoustics ST 5 User Manual  
Worldwide Warranty  
In addition to any local warranty, which may be offered by your Distributor or Retailer, REL  
offers you a conditional three-year Worldwide Warranty.  
The conditions of this warranty are:  
1. That the warranty shall be for a term of three years from the date of purchase.  
2. That the warranty is ineffective until registration is received by REL.  
3. That the product is not exported from the country of purchase for at least eight weeks  
after purchase.  
4. That any claim is accompanied by the necessary proof of purchase.  
5. That the product was purchased from an authorised REL dealer.  
6. That the product has not been abused or modified in any way.  
The Warranty is transferable provided REL has been notified prior to the transfer.  
Notification must include the model, serial number, name and address of original purchaser  
and the name and address of the new owner. The Warranty will be valid for the remainder of  
the original period of Warranty.  
This Warranty is offered in good faith and is in addition to any statutory rights or existing  
Warranty that may be offered locally.  
To register for this Warranty, which is offered at no extra cost to you, please complete and  
send the card enclosed or complete and send the Warranty card on the REL web-site:  
Note: If you have purchased more than one sub-bass system, please send a card for each  
one.  
SERVICE AFTER WARRANTY  
UK customers please contact your dealer in the first instance before returning any product  
directly to REL. Should the unit need to be returned for any reason, all carriage costs will be  
payable by the customer. Losses or damage caused during transit are at the customer's risk.  
Overseas customers please refer to the list of distributors on REL’s website.  
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REL Acoustics ST 5 User Manual  
REAR AMPLIFIER PANEL  
CE  
IEC Mains socket and  
On/Off switch  
~ 220-240 VAC 50-60 HZ  
FUSE 2A/T  
DC TRIGGER.  
3.5mm jack 5 to 12 Volts  
5-12V DC TRIGGER  
Strata5  
LFE INPUT.  
150 WATT MOSFET SUB-BASS SPEAKER SYSTEM  
Phono socket. Used to connect  
the sub-bass system at low level  
to the sub/LFE output of the  
AV  
R
LFE LEVEL  
PROTECTED BY  
amplifier/processor/receiver  
Page 13  
HI LEVEL  
HI LEVEL INPUT  
Neutrik Speakon socket. Used  
to connect the Sub Bass System  
at high level to the main  
speaker output terminals of  
amplifiers. Pages 11and 12  
MADE IN GREAT BRITAIN  
Strata 5 amplifier panel shown, Stampede amplifier panel is the same.  
REMOTE CONTROL  
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REL Acoustics ST 5 User Manual  
Most functions are accessible via either the remote or the front panel. Standby and the  
memory are only accessible via the remote. Display timeout, display brightness and DC  
trigger are only accessible via the front panel.  
To prevent accidental changing of parameters once they have been set, the manual  
encoder on the front panel can be electronically locked. To lock the control first press F2  
and then F1 in sequence, the display will read FP 0F (front panel off), to reactivate the front  
panel encoder press F2 and F1 in sequence again, the display will read FP on (front panel  
on).  
Used to raise or lower the volume when  
using the LFE input. Range 00 to 99  
as displayed on the digital readout on  
main control panel.  
Used to raise or lower the volume when  
using the high level input. Range 00 to 99  
as displayed on the digital readout on  
main control panel.  
Used to set the upper roll off point in the  
range 16 to 99 Hz as displayed on the  
digital readout on the main control panel.  
LFE MUTE  
MEMORY  
Single channel graphic equaliser, - 9dB to  
+ 9dB at 80Hz.Display will read –9 ….0….9  
Used to store user preset preferences. See  
below for detailed instructions on how to  
store and recall settings.  
Used to mute the LFE input. Display will  
read LF on or LF oF. Press again to switch  
LFE input back on  
Used to put the sub bass system into  
standby mode. Display shows Stby, press  
again to bring out of standby.  
Used to change the phase from 0 to 180  
Degrees. NOTE: The display will read  
0 and 18.  
Memory Functions  
There are four memory locations for the user to store preferred settings, these are:  
Position 1 Using the MEMORY button in conjunction with the LFE + and – buttons  
Position 2 Using the MEMORY button in conjunction with the HIGH LEVEL + and – buttons  
Position 3 Using the MEMORY button in conjunction with the FREQUENCY + and – buttons  
Position 4 Using the MEMORY button in conjunction with the SLAM/DEPTH + and – buttons  
To Store User Settings  
First select the settings for each function which satisfy your particular requirements, for  
example you may wish to store the settings for two channel use and another set for 5.1 home  
cinema use. When the correct settings are chosen then press the MEMORY button, and one  
of the four memory location + buttons, the settings are now stored in this memory position.  
To recall these settings press the memory button and the relevant memory location – button  
in sequence. The above procedure can be repeated for the other memory locations  
All settings can be stored in memory, including those accessible only via the front panel.  
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REL Acoustics ST 5 User Manual  
Display of Memory Function  
1st. memory position store. Press MEMORY the display will show Pr – (Profile)  
Press LFE + button, the display will show Pr –1 and the settings  
will be stored.  
1st. memory position recall. Press MEMORY the display will show Pr – (Profile)  
Press LFE - button, the display will show Pr 1 and the settings  
will be recalled.  
Repeat the above procedure for memory positions 2,3 and 4 using the HIGH LEVEL,  
FREQUENCY and SLAM/DEPTH + and – buttons.  
For memory position 2 display will show Pr –2 to store and Pr 2 to recall  
For memory position 3 display will show Pr –3 to store and Pr 3 to recall  
For memory position 4 display will show Pr –4 to store and Pr 4 to recall  
CONTROL PANEL  
DISPLAY  
ENCODER  
All the functions shown on page 9 and 10 are available via the remote control and the  
encoder on the front control panel.  
When using the front control panel, the functions are accessed by sequential presses of the control  
knob, the function being displayed on the two left hand digits of the seven-segment display. When the  
required function is accessed, the value can be adjusted by rotating the control knob, the value being  
displayed on the two right hand digits of the seven-segment display.  
FACTORY DEFAULT SETTINGS  
Before the MEMORY positions are programmed with the user’s preferences they are all pre  
programmed with factory defaults as follows:-  
LFE  
30  
HIGH LEVEL  
FREQUENCY  
SLAM/DEPTH  
LFE MUTE  
30  
30  
0
Off  
PHASE  
0
DISPLAY TIMEOUT  
DISPLAY BRIGHTNESS  
DC TRIGGER  
Off  
Max (10)  
Hi  
To reset factory defaults, switch off the unit by means of the rear mains ON/OFF switch.  
Then switch back ON as you hold in the encoder knob on the control panel, continue to hold  
the knob in until the decimal point on the right hand digit appears. You will now have reset to  
the original factory defaults.  
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REL Acoustics ST 5 User Manual  
CONTROL PANEL DISPLAY  
The following options are available via the remote control and the encoder on the control panel.  
LFE input volume. Select by pressing LFE + or – buttons  
on the remote control or pressing the control knob on the  
control panel until ‘LF’ shows on the display.  
Adjust level by pressing the + or – buttons on the remote  
control or rotating the control knob on the control panel.  
Level will show in the range 00 to 99  
High Level input volume. Select by pressing + or –  
buttons on the remote control or by pressing the control  
knob on the control panel until ‘Hi’ shows on the display.  
Adjust level by pressing the + or – buttons on the remote  
control or by rotating the control knob on the control panel.  
Level will show in the range 00 to 99  
Frequency. Select the roll-off frequency by pressing the +  
or – buttons on the remote control or by pressing the  
control knob on the control panel until ‘Fr’ shows on  
display.  
Adjust cut-off point by pressing the + or – buttons on the  
remote control or by rotating the control knob on the control  
panel.  
Slam/Depth. Select the Slam/Depth option by pressing the  
+ or – buttons on the remote control or by pressing the  
control knob on the control panel until ‘Sd’ appears on  
display.  
Adjust level of Slam/Depth by pressing the + or – buttons  
on the remote or by rotating the control knob on the control  
panel.  
LFE MUTE. Select the LFE MUTE option by pressing the  
LFE mute button on the remote control or by pressing the  
control knob on the control panel until LF appears on the  
display.  
Change the state to on or off by pressing the LFE MUTE  
button on the remote control again or rotating the control  
knob, the display will read LF on or LF oF.  
MEMORY. This function is only available via the remote  
control.  
For operation see pages 7 and 8  
Phase. Phase is selected by pressing the button labelled  
PHASE on the remote control, display will read Ph 0 or Ph  
18 representing 0 degrees or 180 degrees.  
Phase can also be selected by pressing the knob on the  
control panel until Ph is displayed, the 0 degrees or 180  
degrees is selected by rotating the control knob.  
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REL Acoustics ST 5 User Manual  
Use this function to lock the control panel encoder, this will  
prevent user settings being changed accidentally.  
Press MEMORY and then LFE MUTE buttons, display will  
read FP on or FP oF. FP on means front panel control active,  
FP oF means front panel control locked.  
Pressing the standby button on the remote control switches the  
sub bass unit in or out of standby mode.  
Press the STANDBY button and the display will read Stby  
briefly and then default to just four flashing dots. Another press  
of the STANDBY button will bring it back to life.  
ADDITIONAL FUNCTIONS  
(Only available via the encoder on main control panel)  
Display Time Out. Enables the display to be  
turned off after a pre-set time or left on  
continually.  
- - indicates ‘always on’ or select 1 to 59 seconds  
for display off. Select by pressing the control  
knob until ‘dt’ appears on the two left hand digits,  
rotate knob to set value as displayed on the two  
right hand digits.  
Display Brightness. Adjusts the display  
brightness from 01 ‘dim’ to 10 ‘full brightness’.  
Select by pressing the control knob until 'br'  
appears on the two left hand digits, rotate knob to  
set value as displayed on the two right hand digits.  
DC TRIGGER. Custom install feature. Used for  
remote control of sub by other equipment.  
Select by pressing the control knob until ‘tr’  
appears on the two left hand digits. Rotate knob to  
select value Hi or Lo. Please consult your dealer  
on use of this feature.  
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REL Acoustics ST 5 User Manual  
CONNECTING UP  
Always switch off your system before disconnecting any wires  
To enhance connection versatility, the “St” range has a range of separate inputs depending  
on the model, see page 8.  
To connect to the power amplifier using the UNBALANCED Neutrik high  
level input.  
To engage the Neutrik Speakon plug, insert fully into socket and rotate clockwise until locked.  
To remove the Neutrik Speakon plug, grip body of plug, place thumb on chrome lever, move  
lever backwards and rotate plug anti-clockwise (counter-clockwise in the US) a quarter turn  
and withdraw.  
The high level input* is designed to accept the stereo (two channel) signals from the speaker  
terminals of your receiver, integrated amplifier, or power amplifiers. This has the advantage  
of ensuring that your sub-bass system receives exactly the same signal as the main  
speakers, and ensures that the character of the bass from the main system is carried forward  
into the sub-bass. This is a very important factor in the successful integration of your sub-  
bass with the main system and works with the REL’s ABC circuitry to ensure a superior result.  
*This input is labeled “Hi LEVEL”. This is the recommended means of connecting the  
sub for two-channel use.  
Supplied Neutrik Speakon High level Interconnect  
HI LEVEL input  
Release lever  
YELLOW  
BLACK  
RED  
+
L
-
+
R
-
Amplifier main speaker outputs  
High Level connections should be made to the same binding posts as the main speakers.  
Connect as shown above. Red to the amplifier’s primary right speaker red terminal, yellow to  
the amplifier’s primary left speaker red terminal and black to one of amplifier’s primary  
speaker black terminals (not both).  
Plug the Neutrik Speakon plug into the HI LEVEL Neutrik socket.  
The output level can be adjusted by one of two methods:  
1.  
2.  
By using the remote control: press the buttons marked HIGH LEVEL ‘+‘or ‘-‘. The  
front control panel will show ‘Hi’ on the two left hand digits. The volume level can be  
adjusted up or down by pressing the + or – buttons. The display will show 00 to 99 on  
the two right hand digits.  
By using the encoder control on the front control panel: press the control knob to  
select ‘Hi’ on the two left hand digits, rotate control knob to select the value in the  
range 00 to 99 on the two right hand digits.  
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REL Acoustics ST 5 User Manual  
To connect to MONO BLOCK power amplifiers using the High Level  
Neutrik UNBALANCED input  
To engage the Neutrik Speakon plug, insert fully into socket and rotate clockwise until locked.  
To remove the Neutrik Speakon plug, grip body of plug, place thumb on chrome lever, move  
lever backwards rotate the plug anti-clockwise (counter-clockwise in the US) a quarter turn  
and withdraw.  
Supplied Neutrik Speakon High level Interconnect  
RED  
HI LEVEL input  
Release lever  
BLACK  
YELLOW  
+
-
+
-
L
R
MONO  
BLOCK  
MONO  
BLOCK  
SPK OUT SPK OUT  
PRE AMPLIFIER  
GROUND (see below)  
High Level connections should be made to the same binding posts as the main  
speakers  
Using a single sub-bass system, connect as shown above. Connect RED to right monoblock  
speaker positive (red) terminal, connect YELLOW to left monoblock speaker positive (red)  
terminal. The BLACK should be connected to ground at the pre amplifier. If the pre amplifier  
does not have a dedicated ground terminal, then use one of the chassis screws at the rear of  
the pre amplifier.  
NOTE: MAKE SURE THAT ANY CHASSIS SCREW THAT IS CHOSEN IS NOT  
CAPTURED ON THE INSIDE WITH A NUT AS THE NUT COULD DROP INSIDE THE UNIT.  
The output level can be adjusted by using one of the two methods described in the last  
section.  
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REL Acoustics ST 5 User Manual  
To connect to the amplifier/processor/receiver using the phono to phono  
LFE interconnect  
Phono to Phono Interconnect.  
To sub/LFE output of  
Amplifier/Processor  
Sub LFE  
Input  
Connect as shown above using a phono to phono interconnect. Plug one end into  
the sub/LFE output on the amplifier/processor and the other end into the LFE LEVEL  
input on the sub-bass system.  
The output level can be adjusted by one of two methods.  
1. By using the remote control: press the buttons marked LFE LEVEL ‘+’ or ‘-‘. The front  
control panel will show ‘Hi’ on the two left hand digits. The volume level can be adjusted  
up or down by pressing the ‘+’ or ‘-‘ buttons and the display will show 00 to 99 on the two  
right hand digits.  
2. By using the encoder control on the front control panel: press the control knob to select  
‘LF’ on the two left hand digits, rotate control knob to select the value in the range 00 to  
99 on the two right hand digits.  
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REL Acoustics ST 5 User Manual  
REL SET-UP MADE SIMPLE  
REL designs are not traditional subwoofers, but true sub-bass systems. A REL is designed to  
augment the performance of “full range” speaker systems, to provide linear response down to  
below 12 Hz (Studio III, -6 dB down at 9 Hz). Therefore, for the moment, set aside everything  
you’ve been taught about subwoofers and how they are integrated into a stereo or theatre  
system. REL’s set-up and positioning differs from other subwoofers. A REL will take  
advantage of physics and room acoustics to provide deep pressurisation of the kind no  
ordinary sub-woofer can deliver. It’s important that you bring to the set-up process a  
willingness to do things a little differently in order to obtain these superior results. The result of  
your labours will be an utterly seamless integration of genuine sub-bass to a sound system,  
regardless of the main speaker’s low bass capability.  
Two Things Before You Begin  
A.  
It is helpful to know that you will almost always connect the REL to the input on the  
rear panel labelled “Hi Level.” This connection is made using the supplied cable, the  
bare leads of which connect to the speaker output terminals of the power amplifier.  
The easy connection at the REL is completed with a Neutrik Speakon connector. The  
purpose of connecting to the speaker output terminals is one of the unique secrets of  
REL’s success. By connecting to the REL’s High Level input from the amplifier, you  
build forward the sonic signature of your main system, including the tonal balance  
and timing cues. In this way, the REL shares the signal that is fed to the main  
speakers.  
B.  
When possible, the REL should be placed in one of the corners behind the speakers.  
A REL sub-bass system will deliver true LOW bass pressurisation, not the mid-bass  
that most competitors settle for. Low bass pressurisation below 30Hz is best derived  
from corner placement, where the most linear and efficient low bass can be  
generated.  
Basic set-up should take no more than ten to fifteen minutes to accomplish once connected.  
Connecting  
High Level connection: using the enclosed cable with the Neutrik Speakon connector  
is always the first choice. By connecting to the amplifier’s speaker outputs the sonic  
signature of the entire amplification chain is folded into the signal for the sub, thereby  
keeping timing and timbre cues consistent. This connection can be made without  
affecting the performance of the amplifier because the sub-bass system’s amplifier  
input impedance is 10,000 ohms. This method also avoids the detrimental effects of  
additional electronics in the amplification chain.  
The High Level hook up procedure is explained above.  
Positioning  
The optimal position for a REL is in one of the corners behind the main speakers. This  
position provides 9 dB of acoustic amplification and allows for the most linear true low bass  
wave generation.  
The Process  
To begin the set-up process, choose a piece of music that has a repetitive bass line, which is  
very low in frequency. Cut 4 from the soundtrack to Sneakers (Columbia CK 53146) has a  
repetitive bass drum throughout, which gives you plenty of time to move the woofer around.  
The recording venue was quite large for this recording, and therefore it has a very deep and  
large-scale bass signature. This type of recording is perfect for the set-up process, and  
should be played at the highest reasonable level expected for system playback.  
With the REL remote control, adjustment of each stage is simplicity itself to achieve.  
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REL Acoustics ST 5 User Manual  
Trying to ignore all other music in the cut, listen for the bass drum and its effect on the  
listening room.  
1. Phase Orientation: Once in the corner we need to adjust for phase. This may be the  
single most critical step, and because it really is quite simple, it is often over looked  
by even the most experienced audiophiles. The right phase is whichever position is  
the loudest or fullest. While playing music with true low bass, adjust the crossover to  
a point where the sub and the speaker are sure to share frequencies (40Hz for big  
speakers or 60Hz for smaller speakers). At this point turn the gain so that both sub  
and speaker are roughly equal in volume and then, using the “Phase” button on the  
remote control, change from 0 to 180 degrees (this shows as 0 and 18 in the display).  
Select the option that sounds loudest or fullest from the listening position. At this  
setting, the sub-bass system is working in harmony with your main speakers,  
reinforcing bass, and not cancelling it. Don’t be surprised if the chosen position  
shows as 180 degrees “out” of phase. Within your room/system it is IN phase.  
Alternatively the phase can be changed using the control knob on the front of the  
cabinet. Although perfectly feasible, the remote is the preferred method as the  
assessment can be done from the usual listening position and is the more accurate  
way of achieving the best result.  
2. Room Orientation: Next, if space allows, try two different orientations of the woofer  
relative to the wall. First, while playing the set-up cut, place the REL with the  
connection panel parallel with the rear wall. Second, place the REL with the  
connection panel parallel with the sidewall. As with phase, the orientation which  
yields the most output is the best position for that room. This process simply positions  
the driver to most efficiently drive the room. In some instances there may be little  
difference, at which point aesthetic concerns may override performance concerns.  
3. Placement: The next step is to determine precisely how far out from the corner of the  
room the sub should be placed to achieve the most efficient output, as well as the  
lowest frequency extension. With the sub fully into the corner and continuing to play  
the music, slowly pull the sub from the corner on the diagonal, equidistant from both  
side and rear walls. Do this a couple of centimetres (an inch) at a time. At a certain  
point (sometimes a matter of only a few centimetres, in rare cases up to 25  
centimetres or more) the sub will audibly go lower, play louder, and if it truly locks on  
to the room and is fully pressurising it, the air around the sub will seem to be  
energised, stop right there! This is the correct position for the sub.  
Crossover and gain settings  
The last stage of the set up is crossover and gain. You will require an acoustically recorded  
track preferably with bass instruments and vocal. What we are looking for here is a seamless  
crossover and integration between your main speakers and the sub-bass system. Firstly you  
will need to set a rough volume level. To do this leave the crossover where it is and simply  
play the system varying the volume until you have a happy medium between the speakers  
and sub, the sub will sound obvious still but this is just the start.  
Next reduce the frequency to minimum (16Hz). Using the same track, gently increase the  
frequency 1 Hz at a time. What you are listening for is the point where the sub begins to  
sound obvious within the system (usually somewhere between 20Hz and 33Hz with most  
loudspeakers). Once you find the point where you can hear the sub over the response of the  
speakers reduce the setting by 1 to 3 Hz This is not an exact science, but what we want is the  
sub to be invisible within the system sonically. In short we increase the REL until you can  
hear it and then reduce until you cannot.  
Finally adjust the volume to taste. This generally will be by 1 or 2 positions. And that’s it. All  
that’s left is to open a good bottle of wine, relax and enjoy.  
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REL Acoustics ST 5 User Manual  
Hint: There is a tendency among audiophiles to set the crossover point too high and the gain  
too low when first learning how to integrate a REL with the system, the fear being one of  
overwhelming the main speakers with bass. But in doing so, the resulting set-up will be  
lacking in bass depth and dynamics. The proper crossover point and gain setting will increase  
overall dynamics, allow for extended bass frequencies, and improve soundstage properties.  
Please note: gain must be adjusted in conjunction with crossover changes. In general, when  
selecting a lower crossover point, more gain may need to be applied.  
Theatre and Film Applications: For DolbyDigital or other surround sound theatre systems,  
once the standard set-up for two-channel outlined above is complete, the LFE output from the  
processor or receiver should be connected to the low-level input and appropriate gain  
adjustments made. Keep phase consistent with what was selected during high-level set-up.  
For this configuration, you must set the processor to the “large” or “full range” setting for the  
left and right speakers in order for the REL to receive the bass signal via the high-level cable.  
In this setting, the REL provides support for both the left and right speakers for two-channel  
listening, and support for the LFE when movies are playing. Most processors will allow you to  
defeat the subwoofer output when listening in the two-channel mode, however, if this is not  
the case, simply press LFE Mute on the remote (or via the control panel) and save the setting  
to memory for future stereo use. The effect of this set-up is one of greatly increased dynamics  
in the mid-bass range; no bass bloat; and a greater degree of space and timing from the  
Foley effects. For an even greater sense of space and impact, a second woofer connected in  
parallel to the centre channel will prove to be a dramatic improvement as well. And if that is  
not enough for you, a rear sub, both to support the rear channel speakers as well as to evenly  
distribute LFE through the room, truly completes the full-range sonic picture for state-of-the-  
art film reproduction.  
Some rooms, notably in houses of wooden construction, can sound bass “light”. To  
overcome this disadvantage, the new RELs offer variable Slam and Depth. Simply adjust the  
+ and buttons marked Slam and Depth on the remote, or navigate to the display using the  
front panel encoder and adjust to compensate for the room.  
Of course, some rooms,  
especially smaller brick built ones, may be bass heavy at around the mid bass area, in which  
case reduce this effect by again using the Slam and Depth control.  
Remember that all these settings can be saved into memory.  
Note: Some processors output a signal from their LFE socket, even when playing a CD in  
Stereo mode. In the past little could be done, now using the remote, simply mute the LFE.  
This is recommended for Stereo mode listening and can be saved along with the other  
options.  
Other Tips: Generally speaking, do not use the supplied spikes. RELs work on the principle  
of the driver being in a high-pressure zone relative to the floor. Spiking the REL will decouple  
the woofer from the floor, which will lean out the bass response. If the floor is an older, very  
“springy” floor, spikes can be useful in reducing the influence of the REL on the floor. A  
heavy stone slab under the REL will further improve performance. Even if you intend to use  
the spikes, do NOT insert them until completion of the set-up process. After which, subtle  
adjustments to crossover and gain may be necessary  
16  
 
REL Acoustics ST 5 User Manual  
RUNNING IN  
Care taken over running in will be rewarded by many years of pleasurable use. Both the  
electronics and the drive unit will benefit from an initial period of carefully controlled use.  
Possible damage may be sustained by running in the unit at too high a volume setting over an  
extended period. On the other hand, by taking a little care over this initial period - about 24  
hours of actual use - a longer life with a higher potential eventual performance is assured.  
OVERLOAD PROTECTION  
REL sub-bass systems are designed as true sub-bass generators. They are designed to  
reproduce those exceptionally deep notes that are felt rather than heard. They will attempt to  
do this at whatever volume level you set. If the volume is set too high, no damage should  
result because the built-in electronics will limit the cone movement. This electronic control is  
called Set-Safe®. It constantly and instantaneously monitors the output from the power  
amplifier and is totally transparent in operation until required. This means it has absolutely no  
effect on the sound quality of any REL Sub-Bass System until an overload is detected.  
Ordinarily an overload would cause the power amplifier to go into clipping with resultant loss  
of control over the drive unit. Apart from being sonically offensive, this can cause drive unit  
damage. Set-Safe® detects the point of incipient clipping and reduces the signal level to  
ensure actual clipping does not occur.  
Even without Set-Safe®, overload would be a difficult thing to achieve because REL sub-bass  
systems have particularly high current amplifiers and very powerful drive units specifically  
designed for high sound pressure levels.  
From our tests, we believe it would be very difficult to deliberately damage a REL sub-bass  
system. Nevertheless, anything can be damaged if sufficient effort is made. Although  
everything possible has been done to minimise damage from moderate attempts at  
overloading, there can be no defence against those individuals who deliberately and  
perversely abuse the device. Such damage is NOT covered by Warranty. Please remember,  
a REL sub-bass system is there to supplement your main system, not to overwhelm it!  
CARE AND POLISHING  
Brittex (sprayed) finishes:  
These are best maintained by careful dusting with a lint free cloth. Alternatively, a soft  
bristled brush may be used to sweep off any dust falling on the surface. If objects are to be  
placed upon the top, it is advisable to use a small mat to protect the surface and to avoid the  
risk of rattles.  
Wood veneer finishes:  
Dusting as above, plus the occasional polishing with a good quality furniture polish for the  
wood veneers. Treat the finish as you would any other piece of quality furniture in your home.  
17  
 
REL Acoustics ST 5 User Manual  
POWER SAVING EFFICIENCY  
All REL sub-bass systems are designed for maximum power efficiency, when operational and  
also when at rest.  
REL circuitry is designed for “power starvation” operation when no signal is present. However  
it remains at maximum readiness to respond immediately to a sudden transient signal, such  
as an explosion in a movie, even after an extended period of rest and at whatever level.  
REL’s maximum power efficiency should not be likened to ‘auto power on/off‘ systems, which  
‘power-down’ after a set period of rest (up to 10-15 minutes) and which need time to power-up  
again when required to reproduce a sudden transient. They invariably fail to respond to the  
leading edge of that transient. There is also the possibility of ‘auto power on/off‘ systems  
remaining inoperative during quiet listening sessions.  
It is not necessary to switch the REL sub-bass system off between listening sessions; leaving  
it switched on will not significantly shorten its life. On the other hand, sound quality will not be  
affected if the system is always switched off. Power consumption in the quiescent (no signal)  
state is negligible. REL’s power starvation technology uses less than 4W when idle (less than  
1/25th the power of a standard light bulb).  
The system is perfectly safe under all normal domestic circumstances as it is fully protected  
by internal fuses and an external mains fuse, located in the sliding drawer of the mains input  
socket. There is also a spare fuse inside this drawer.  
18  
 
REL Acoustics ST 5 user manual  
SPECIFICATIONS  
MODEL  
STAMPEDE  
Closed box loading  
16Hz to 99Hz  
STRATA 5  
TYPE  
Closed box loading  
ROLL OFF  
16Hz to 99Hz  
-3dB 18Hz  
IN ROOM RESPONSE  
INPUT CONNECTORS  
-3dB 18Hz  
Neutrik Speakon – High  
Level  
Neutrik Speakon – High Level  
Phono - LFE  
Phono - LFE  
GAIN CONTROL RANGE 80dB  
80dB  
AMPLIFIER TYPE  
DC Coupled Mosfet  
Microprocessor Controlled  
DC Coupled Mosfet  
Microprocessor Controlled  
Digital readout for all functions  
Electronic lock for manual encoder to prevent accidental changes  
INPUT IMPEDANCE  
HIGH LEVEL TWO  
CHANNEL  
UNBALANCED  
LOW LEVEL (LFE)  
UNBALANCED  
100K Ohms  
10K Ohms  
100K Ohms  
10K Ohms  
INPUT SENSITIVITY  
LOW LEVEL  
50mV  
50mV  
HIGH LEVEL  
500mV  
500mV  
SLAM AND DEPTH  
DRIVE UNIT  
-9dB to +9dB at 80Hz  
8” Heavy Duty Long Throw  
100 Watts RMS  
-9dB to +9dB at 80Hz  
10” Heavy Duty Long Throw  
150 Watts RMS  
POWER OUTPUT  
WATTS  
PHASE  
0 and 180 Degrees  
0 and 180 Degrees  
MAINS INPUT VOLTS  
(COUNTRY SPECIFIC)  
PROTECTION  
110 Volts or 230 Volts  
Depending on country  
Set – Safe for driver  
protection  
110 Volts or 230 Volts  
Depending on country  
Set – Safe for driver protection  
MAINS FUSES  
2 Amp semi delay for  
230Volts  
2 Amp semi delay for 230Volts  
4 Amp semi delay for 110 Volts  
4 Amp semi delay for 110  
Volts  
DIMENSIONS WxHxD  
INC. FEET AND  
COINTROL  
280 x 400 x 290  
324 x 464 x 334  
NETT WEIGHT KGS  
13.4  
23.2  
26.1  
GROSS WEIGHT KGS  
15.4  
SUPPLIED ACCSESSORIES  
MAINS LEAD  
Yes  
Yes  
Yes  
Yes  
NEUTRIK SPEAKON  
INTERCONNECT  
(HIGH LEVEL)  
PHONO TO PHONO  
INTERCONNECT (LFE)  
SPIKES  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
USER MANUAL  
REMOTE CONTROL  
(WITH BATTERIES)  
19  
 
REL Acoustics ST 5 user manual  
20  
 

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