REL Strata II - User Manual

REL
Operating Instructions
for the
Strata II
Sub-Bass System
REL Acoustics Ltd
North Road, Bridgend Industrial Estate,
Bridgend, Mid Glamorgan, CF31 3TP.
United Kingdom.
Telephone: 01 656 768 777; International: +441 656 768 777
Fax: 01 656 766 093 International: +441 656 766 093

Summary

Operating Instructions

WELCOME

World Wide Warranty

Details REL's 3-year conditional worldwide warranty for the end user.

Service After Warranty

Instructions for contacting dealers for service and handling return costs.

Handling Warning

Cautionary note about the weight of the item and risk of injury.

Connecting Your Strata II

Connect to Power Amplifier

Explains connecting via loudspeaker outputs using Neutrik Speakon.

Connect to LFE or Preamp Output

Describes connecting to LFE or preamp outputs using phono sockets.

Setting Up and Running-In

Setting Up Procedure

Guide on initial testing, phase reversal, gain, and filter adjustments.

Running-In Procedure

Recommends a period of controlled use for electronics and drive units.

Care of Your Strata II

Instructions for cleaning and maintaining the unit's finish.

Some Dos and Donts

Specifications

Please Note

UK Operation

Details specific mains plug, fuse replacement, and wiring for UK operation.

Important Wiring

Explains the importance of correct wire-to-terminal connections for mains power.

Overview

1. Important Technical Specifications
2. Usage Features
3. Setting Up and Running-In
4. Maintenance Features
5. Safety and General Guidelines
6. Supplied Accessories

The REL Strata II is a sub-bass system designed and handcrafted by REL Acoustics Ltd in the United Kingdom. Its primary function is to enhance the low-frequency reproduction of an audio system, providing deep, accurate bass that is felt as much as it is heard. The Strata II aims for seamless integration with main loudspeakers, addressing challenges in bass reproduction and room matching for various room sizes and configurations.

Important Technical Specifications:

• Type: Reflex Extended response
• Enclosure Volume: 40 litres
• Input Connectors: Neutrik Speakon and twin phono sockets
• Bass Cut Outputs:
  • Cut below 50Hz
  • Cut below 100Hz
  • (Both measured into 10k ohms impedance)
• Gain Control Range: 80dB
• Amplifier Type: DC coupled complementary Mos-Fet
• Input Impedances:
  • High Level: 100K Ohm Unbalanced (Neutrik Speakon)
  • Low Level: 10K Ohm Unbalanced (RCA Phono)
• Power Output: 60 Watts R.M.S.
• Drive Unit: Magnesium chassis, long throw 25cm
• Frequency Range: 20-120Hz (upper frequency dependent upon user settings of ABC. Lower limit is room dependent).
• Phasing: Positive, or reversed. Phase Switch Position 1 gives Forward Cone Movement for Positive Input.
• Mains Input: 220 - 240V (or 110 - 120V in certain markets) via fused I.E.C. standard socket.
• Fuse:
  • 1 x 630mA semi-delay (220 - 240V)
  • 1 x 1.25A semi-delay (110 - 120V)
  • Spare fuse in sliding drawer. Replace only with similar type.
• Dimensions: 416 x 518 x 310mm (W x H x D), approximately 16.5 x 20.5 x 12 inches.
• Weight: 18Kg, approximately 39lbs.

Usage Features:

The Strata II offers two primary methods for connection to an audio system, emphasizing flexibility and optimal sound integration:

1. Connection to the Power Amplifier (High Level Input): This is the preferred method for achieving the highest possible sound quality. It involves connecting the Strata II directly to the loudspeaker outputs of the power amplifier using the supplied Neutrik Speakon signal interconnect. This ensures that the Strata II receives the exact same signal as the main speakers, promoting superior system integration. The Strata II effectively "bi-wires" from the power amplifier, with specific connections for right, left, and a single black wire for earthing to maintain the system's star earthing arrangement. This method, combined with the Strata II's Active Bass Controller (ABC), provides sophisticated control over sub-bass integration. For Dolby AC3 equipment, both high and low-level inputs can be used simultaneously: the full-range signal from speaker outputs for integration with the front system, and the sub-bass effects from the LFE output. Multiple Strata II units can be used for greater dynamic range and bass extension in such setups.

2. Connection to a Dedicated Sub-Woofer (LFE) Output or Preamp Output (Low Level Input): This method utilizes the Strata II's phono sockets. It can connect to an LFE output (if available), a television's headphone audio output, or a spare pair of preamp output sockets. An optional phono-to-phono interconnect may be required. If a separate preamp and power amplifier are used, the preamp's output can be routed through the Strata II to cut bass to the main speakers. This is recommended only when maximum power handling capability is prioritized over main signal purity, as it may affect the main signal. It's important to note that if the NEUTRIK SPEAKON input is used, there will be no output from these phono sockets.

Setting Up and Running-In:

• Spike Installation: Screw the supplied spikes into the steel inserts in the sub-woofer's feet and level them. Do not overtighten; use the lock-nut to secure them.
• Initial Placement: For initial setup, the Strata II can be placed in any convenient position to test controls. For the loudest and deepest bass, positioning it with its back to a wall or in a corner is recommended.
• Phase Reversal Switch: The Strata II features a phase reversal switch (positions 1 and 2) to partially cancel frequencies around the crossover point. Users should listen to both positions and choose the one that provides the tightest and cleanest bass. Position 1 indicates positive phase.
• Active Bass Controller (ABC): This unique feature allows for precise adjustment of the sub-bass frequency.
  • Initially, turn both filter controls fully clockwise (maximum bandwidth) and adjust the gain control to match sound levels with the main system.
  • Then, reduce both filters to their minimum position.
  • Increase the gain control until deep bass is heard.
  • Slowly increase the coarse control one step at a time. If a position is too much, reduce it and then increase the fine control notch by notch until a good match is achieved. Readjust the gain control as needed.
  • The ABC helps compensate for room acoustics, allowing the user to hear very low frequencies properly.
  • The "SWITCH POSITIONS" table (Coarse, Fine, Frequency Hz) provides a guide for setting the upper frequency limit, ranging from 30Hz (Coarse 1, Fine 1) to 120Hz (Coarse 4, Fine 4). The lowest operating frequency is unaffected.
• Running-In: An initial period of approximately 12 hours of carefully controlled use is recommended for both the electronics and drive units. During this time, avoid running the unit at excessively high volumes to prevent permanent damage to the driver, which is not covered by warranty. Proper running-in ensures a longer life and higher eventual performance.

Maintenance Features:

• Cleaning: The high-quality finish can be maintained with an occasional wipe with a damp cloth or by sweeping off dust with a soft-bristled brush.
• Protection: If objects are placed on top of the unit, a small mat is advisable to protect the surface and prevent rattles.
• Durability: The Strata II is designed and engineered for a lifetime of use.

Safety and General Guidelines:

• Water Protection: Always protect the sub-woofer from getting wet.
• Earthing: Ensure the panel is correctly earthed via the three-core mains cable. Relying on the signal ground for earthing is insufficient.
• Mains Lead: If the mains lead is lengthened or shortened, ensure wires are correctly terminated before switching on.
• Fuse Replacement: In case of fuse failure, replace it only with an identical one of the same rating and characteristics. Replacements are available from the supplier. Do not use without the fuse cover.
• Warranty Void: Do not attempt to remove the panel or the drive unit from the enclosure, as this will void all warranties.
• Control Force: Never force the switches or gain control beyond their natural stops.
• Modifications: Do not attempt to modify the design or place objects into the reflex port.
• Power On/Off: It is not necessary to switch off the unit between listening sessions; leaving it on will not significantly shorten its life. Switching it off will not harm sound quality. Quiescent power consumption is negligible.
• Safety: The unit is fully protected and safe under normal domestic circumstances.
• UK Operation: The apparatus is supplied with a fitted three-pin mains plug with a 5 amp fuse. If the plug is cut off, it must not be reused and should be safely disposed of to avoid electric shock. Wiring colours for mains leads (Green and Yellow for Earth, Blue for Neutral, Brown for Live) must be connected to the corresponding terminals (E/earth symbol, N/Black, L/Red) in a replacement plug.
• Compliance: The product is CE marked and complies with EN 50081-1 (EN 55022 class B, IEC 801-4), as well as BS EN 60065 1994 (clauses 9 & 10) for class II construction. It also satisfies relevant safety tests for consumer use when operated within manual guidelines.

Supplied Accessories:

• Mains lead
• 10-metre Neutrik Speakon interconnect
• Operating manual
• Set of spikes

REL Strata II Specifications

General

Brand	REL
Model	Strata II
Category	Subwoofer
Language	English