Sennheiser RS 175-U – Wireless Over Ear TV Headphone System

Sennheiser RS 175-U – Wireless TV Headphone System

Taking home entertainment to the next level, Sennheiser's RS 175-U offers an impressive range of features in a compact, ergonomic package, so that you can enjoy music and television to the fullest. The RS 175-U wireless headphone system delivers rich, detailed sound through closed, circumaural headphones with exceptional digital wireless audio transmission and a range of up to 100 meters. With adjustable dynamic bass boost and two virtual surround sound modes, you can fully exploit the sound potential of your home entertainment system. The system supports both analog and digital audio inputs simultaneously, and the multi-purpose TR 175 transmitter functions as a charging cradle and docking station while supporting up to two pairs of headphones at once.

• Wireless, over-ear, closed circumaural headphone system with transmitter/charging dock
• Dynamic transducer with neodymium magnets
• Frequency response: 17 Hz – 22,000 Hz
• Digital 2.4 GHz wireless (8-FSK modulation), up to 100 m range
• Dynamic bass boost and two virtual surround sound modes (LO/HI)
• Battery: 2 × AAA NiMH rechargeable (1.2 V, 820 mAh), up to 18 hours operating time
• Transmitter inputs: optical digital and 3.5 mm analog; supports up to 2 headphones simultaneously
• Weight: HDR 175 approx. 310 g (incl. batteries)
• 2 Year Warranty

Highlights & Key Features

Digital Wireless Transmission
The RS 175-U uses innovative digital wireless technology operating in the 2,406 to 2,474 MHz frequency band with 8-FSK digital modulation and a maximum RF output power of 10 dBm. This provides crystal-clear, high-fidelity audio as you move from room to room, with an exceptional transmission range of up to 100 meters (328 feet) with free line of sight. The system uses automatic frequency management to ensure the best possible radio transmission and optimum co-existence with other wireless devices in its vicinity. If you leave the transmission range, sound drops out occasionally at first before the connection breaks down completely. If you re-enter within 5 minutes, the connection is automatically re-established; if you spend more than 5 minutes outside the range, the headphones switch off automatically. The transmitter should be placed at least 50 cm (20 inches) away from other wireless devices and not near metal shelves, reinforced concrete walls, or other metal structures that could decrease range.

Dynamic Bass Boost & Virtual Surround Sound
The RS 175-U features adjustable dynamic bass boost and two virtual surround sound modes for individual sound customization. The dynamic bass boost enhances the bass response and can be activated or deactivated via the BASS button on either the headphones or the transmitter, with a dedicated BASS LED indicating the current state. The two virtual surround sound modes — low (LO) and high (HI) — simulate external stereo speakers to create a more spacious and vibrant sound in the headphones. The two modes differ in the intensity of the generated surround sound effect and can be toggled via the SURR button on either the headphones or the transmitter. Surround sound LEDs on the transmitter indicate the selected mode.

Dual Audio Inputs & Input Switching
The TR 175 transmitter supports both analog and digital audio inputs simultaneously, allowing you to connect two audio sources — for example, a TV and a stereo hi-fi system — at the same time. The digital optical input (DIGITAL OPTICAL IN) accepts PCM audio signals only; surround sound formats are not supported, and the connected device's audio format must be set to "PCM" or "stereo." The analog input uses a 3.5 mm jack socket (ANALOG 3.5 mm IN). An AUDIO INPUT SELECTION switch on the transmitter lets you toggle between the digital and analog inputs. For audio sources with RCA outputs, a separately ordered RCA-to-3.5 mm adapter is required. For 6.3 mm (¼") headphone jacks, a separately ordered 3.5 mm-to-6.3 mm adapter is needed. The supplied optical digital cable is 1.5 m and the supplied stereo audio cable with 3.5 mm jack plugs is 2 m. Some TV models mute the internal loudspeakers when the transmitter is connected to the headphone socket; check the TV menu to see if this can be deactivated.

Multi-Receiver Transmission
The TR 175 transmitter supports up to two pairs of headphones simultaneously, allowing two listeners to enjoy the same audio source at their own preferred volume levels. Compatible headphones include the HDR 165, HDR 175, HDR 185, and HDR 195. Other Sennheiser wireless headphones (e.g. RS 11x series, RS 12x series, RS 160, RS 170, RS 180, RS 220) are not compatible and cannot be used. When simultaneously using different types of headphones, bear in mind that they will differ in both sound characteristics and operation. If one pair of headphones is being charged, you can pair a second pair by placing them as close as possible to the transmitter, switching them on, and pressing the Volume +/– buttons simultaneously for about 7 seconds.

Battery & Charging
The HDR 175 headphones are powered by two low self-discharge NiMH rechargeable batteries (AAA size, 1.2 V, 820 mAh) providing up to 18 hours of operating time. A complete charging cycle takes about 8.5 hours. Before first use, charge the batteries for at least 16 hours without interruption to optimize performance; the first charging cycle takes longer because it is used to determine the maximum capacity of the batteries. The intelligent battery charging technology charges the batteries both effectively and gently and prevents overcharging. When not in use, place the headphones on the transmitter's headphone holder to keep the batteries charged. When the batteries are almost empty, the HDR status LED lights red and you hear beeps in the headphones; the headphones switch off after a few minutes. When you remove the headphones from the holder, the Charge status LED on the transmitter indicates approximate operating time: green flashing patterns indicate capacity from 0–25% (up to 4 hours) through 75–100% (approx. 14 to 18 hours). Standard non-rechargeable AAA batteries (1.5 V) can also be used, but must not be placed on the transmitter's charging contacts.

Volume & Controls
The HDR 175 headphones feature Volume + and Volume – buttons on the ear cup for independent volume adjustment. When the minimum or maximum volume is reached, you hear a beep. The Power HDR button switches the headphones on (press for approx. 2 seconds) and off (press for approx. 2 seconds), and also serves as a mute toggle during use (single press to mute, press again or press a Volume button to unmute). If muted for more than 15 minutes, the headphones switch off automatically. If there is no audio signal from the transmitter for more than 5 minutes, the headphones also switch off automatically. Volume is adjusted to a low level before toggling between audio inputs to prevent hearing damage from sudden volume jumps.

Comfort & Design
The HDR 175 headphones feature a closed, circumaural (over-ear) design with an adjustable headband and snap-in locking mechanism for easy adjustment. The ear pads are replaceable by twisting counterclockwise to remove and clockwise to lock in place, with L (left) and R (right) markings for correct orientation. The headband padding is replaceable through the repair service. The ergonomic design ensures excellent wearing comfort for hours of use. The multi-purpose TR 175 transmitter functions as a charging cradle, docking station, and headphone stand. Varnish or furniture polish may degrade the feet of the transmitter, which could stain furniture; place the transmitter on a non-slip pad to avoid potential staining. Do not place headphones on a glass dummy head, chair armrest, or similar objects for long periods as this can widen the headband and reduce contact pressure.

Details & Specifications

MODEL INFORMATION
System model: RS 175 (RS 175-U)
Headphones model: HDR 175
Transmitter model: TR 175
Article number (SKU): 508676

HEADPHONE – AUDIO PERFORMANCE
Transducer principle: Dynamic, neodymium magnets
Type: Circumaural, closed
Frequency response: 17 Hz to 22 kHz
Max. SPL: 114 dB at 1 kHz, 3% THD (product page: 114 dB (1kHz, 100 dB))
Total harmonic distortion: < 0.5% at 1 kHz, 100 dB SPL
Magnetic field strength: 2.7 mT

WIRELESS
Transmission frequency: 2,406 to 2,474 MHz
Modulation: 8-FSK Digital
Signal-to-noise ratio: Analog input: typ. 85 dBA at 1 Vrms; Digital input: > 90 dBA
RF output power: Max. 10 dBm
Range: Up to 100 m (free line of sight)
Maximum simultaneously connected headphones: 2

BATTERY
Power supply / Battery type: 2 × low self-discharge NiMH rechargeable batteries, AAA size, 1.2 V, 820 mAh
Operating time: Up to 18 hours
Charging time: Up to 8.5 hours (first charge: at least 16 hours)

TRANSMITTER – CONNECTIVITY
Digital input: Optical (DIGITAL OPTICAL IN) — PCM only, up to 96 kHz sampling rate
Analog input: 3.5 mm jack socket (ANALOG 3.5 mm IN)
Audio input selection: Toggle switch on transmitter (digital/analog)

TRANSMITTER – POWER
Power supply model: NT9-3AW
Nominal input voltage / input current: 100–240 V~ / 100 mA
Power frequency: 50–60 Hz
Nominal output voltage: 9 V
Nominal output current: 300 mA
Power consumption: Operation typ. 4 W; Standby ≤ 0.3 W (without charging)

PHYSICAL SPECIFICATIONS
Headphones dimensions (W × H × D): Approx. 17 cm × 20 cm × 9.5 cm
Headphones weight (incl. batteries): Approx. 310 g
Transmitter dimensions (W × H × D): Approx. 12.7 cm × 23.4 cm × 2.3 cm

ENVIRONMENTAL
Operating temperature: 0°C to +40°C
Storage temperature: –25°C to +70°C
Operating relative humidity: 10% to 80% (non-condensing)
Storage relative humidity: 10% to 90%

POWER SUPPLY UNIT ENVIRONMENTAL
Operating temperature: 0°C to +40°C
Storage temperature: –40°C to +85°C
Operating relative humidity: 0% to 90% (non-condensing)
Storage relative humidity: 0% to 90%

COMPATIBLE HEADPHONES
HDR 165, HDR 175, HDR 185, HDR 195

INCLUDED ACCESSORIES
HDR 175 headphones
TR 175 transmitter
Optical digital cable, 1.5 m
Stereo audio cable with 3.5 mm jack plugs, 2 m
Power supply unit (NT9-3AW) with country adapters (EU, UK, US, AU)
2 × low self-discharge NiMH rechargeable batteries (AAA size)
Quick guide
Safety guide