Page 2 - Important Safety Instructions; WA R N I N G; AV I S
2 Important Safety Instructions 1. Read these instructions.2. Keep these instructions.3. Heed all warnings.4. Follow all instructions.5. Do not use this apparatus near water.6. Clean only with dry cloth.7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructi...
Page 3 - Precautions; For Canadian Models
3 Precautions 1. Recording Copyright —Unless it’s for personal use only, recording copyrighted material is illegal without the permission of the copyright holder. 2. AC Fuse —The AC fuse inside the unit is not user- serviceable. If you cannot turn on the unit, contact your Onkyo dealer. 3. Care —Occ...
Page 4 - Speaker Precautions; Placement
4 Speaker Precautions Placement • The subwoofer cabinet is made out of wood and is therefore sensitive to extreme temperatures and humidity, do not put it in locations subject to direct sunlight or in humid places, such as near an air condi-tioner, humidifier, bathroom, or kitchen. • Do not put wate...
Page 5 - Make sure you have the following items:; Introduction; Controlling Other Components; Others
5 Contents * To reset the AV receiver to its factory defaults, turn it on and, while holding down the [VCR/DVR] button, press the [ON/STANDBY] button (see page 66). Package Contents Make sure you have the following items: HT-R370 * In catalogs and on packaging, the letter at the end of the product n...
Page 6 - Package Contents; —Continued; Speaker Package HTP-370
6 Package Contents —Continued Speaker Package HTP-370 Front speakers(SKF-370 L/R) Center speaker(SKC-370/SKC-370C) Surround speakers(SKR-370 L/R) Subwoofer (SKW-370) Speaker Package Accessories Speaker cable for front speakers 11 ft. (3.5 m) Speaker cable for center speaker 10 ft. (3 m) Speaker cabl...
Page 7 - Features; HTP-370 Speaker Package; SKW-370 Bass Reflex Subwoofer
7 Features HT-R370 AV Receiver • 110 Watts/Channel @ 6 ohms• 100 Watts/Channel @ 6 ohms (IEC)• 120 Watts/Channel @ 6 ohms (JEITA)• H.C.P.S. (High Current Power Supply) Massive High Power Transformer • Dolby Digital and Pro Logic II *1 • DTS and DTS Neo:6 5.1 *2 • Music Optimizer *3 for Digital Audio...
Page 8 - Front Panel; g h i j k l m
8 Front & Rear Panels The actual front panel has various logos printed on it. They are not shown here for clarity. The page numbers in parentheses show where you can find the main explanation for each item. a ON/STANDBY button (35) Set the AV receiver to On or Standby. b STANDBY indicator (35) L...
Page 9 - AUX INPUT; Display; a b
9 Front & Rear Panels —Continued For detailed information, see the pages in parentheses. t Input selector buttons (38) Select the following input sources: DVD/BD, VCR/DVR, CBL/SAT, AUX, TV/TAPE, AM, FM, CD. u AUX INPUT PORTABLE (30): Used to connect a portable Audio player. For detailed informat...
Page 10 - This; Rear Panel; k l
10 Front & Rear Panels —Continued a DIGITAL IN COAXIAL These coaxial digital audio inputs are for connecting components with a coaxial digital audio output, such as a CD player or DVD/BD player. They’re assignable, which means you can assign each one to an input selector to suit your setup. See ...
Page 11 - See pages 15–34 for hookup information.
11 Front & Rear Panels —Continued m CBL/SAT IN A cable or satellite receiver can be connected here. There is composite video input jacks for connecting the video signal, and there are analog audio input jacks for connecting the audio signal. n VCR/DVR IN/OUT A video component, such as a VCR or D...
Page 12 - Speaker Package; Rear
12 Speaker Package ■ Rear a Speaker terminals These push terminals are for connecting the speaker to the HT-R370 with the supplied speaker cables.The supplied speaker cables are color-coded for easy identification. Simply connect each cable to the same-colored positive speaker terminal. b Keyhole sl...
Page 13 - Remote Controller; SETUP button; Controlling the AV receiver; button
13 Remote Controller For detailed information, see the pages in parentheses. a ON/STANDBY button (35) Sets the AV receiver to On or Standby. b REMOTE MODE/INPUT SELECTOR buttons (38, 62–65) Selects the remote controller modes and the input sources. c TONE, +, and – buttons (40) Used to adjust the to...
Page 14 - Installing the Batteries; Replace the cover and push it shut.; Aiming the Remote Controller
14 Remote Controller —Continued Notes: • If the remote controller doesn’t work reliably, try replacing the batteries. • Don’t mix new and old batteries or different types of batteries. • If you intend not to use the remote controller for a long time, remove the batteries to prevent damage from leaka...
Page 15 - Enjoying Home Theater; You can use two sets of speakers with the AV receiver:; Speaker set A; can be used in another room and offers 2-channel stereo playback.; Speaker Sets A and B; Speaker Set A: Main Room
15 Enjoying Home Theater You can use two sets of speakers with the AV receiver: speaker set A and speaker set B . Speaker set A should be used in your main listening room for up to 5.1-channel playback. * While speaker set B is on, speaker set A is reduced to 2.1-channel playback. Speaker set B can ...
Page 16 - Connecting the AV receiver; Speaker Connection Precautions; ohms or higher; Connecting the Speaker Cables; Connecting Your Speakers; Unscrew the terminal.
16 Connecting the AV receiver Speaker Connection Precautions Read the following before connecting your speakers:• You can connect speakers with an impedance of 6 ohms or higher . If you use speakers with a lower impedance, and use the amplifier at high volume levels for a long period of time, the bu...
Page 17 - OTHERS
17 Connecting the AV receiver —Continued OTHERS The following illustration shows which speaker should be connected to each pair of terminals. 1 Strip 3/8" (10 mm) of insulation from the ends of the speaker cables. (Supplied speaker cables are already stripped.) 2 While pressing the lever, insert...
Page 18 - Wall Mounting
18 Connecting the AV receiver —Continued The speakers can easily be wall mounted by using the keyhole slots. To prevent the speaker from vibrating against the wall, attach two of the supplied thick rubber stoppers to the rear of each speaker. To mount the front or surround speakers vertically, use t...
Page 19 - Connecting the Indoor FM Antenna; The supplied indoor FM antenna is for indoor use only.; Connecting the AM Loop Antenna; Connecting Antenna; North American Model
19 Connecting the AV receiver —Continued This section explains how to connect the supplied indoor FM antenna and AM loop antenna, and how to connect commercially available outdoor FM and AM antennas.The AV receiver won’t pick up any radio signals without any antenna connected, so you must connect th...
Page 20 - Connecting an Outdoor FM Antenna; • Outdoor FM antennas work best outside, but usable; Using a TV/FM Antenna Splitter; Connecting an Outdoor AM Antenna
20 Connecting the AV receiver —Continued Connecting an Outdoor FM Antenna If you cannot achieve good reception with the supplied indoor FM antenna, try a commercially available outdoor FM antenna instead. Notes: • Outdoor FM antennas work best outside, but usable results can sometimes be obtained wh...
Page 21 - Optical Digital Jacks; About AV Connections
21 Connecting the AV receiver —Continued • Before making any AV connections, read the manuals supplied with your other AV components. • Don’t connect the power cord until you’ve completed and double-checked all AV connections. Optical Digital Jacks The AV receiver’s optical digital jacks have shutte...
Page 22 - Video Connection Formats; Connecting Audio and Video Signals to the AV receiver; Which Connections Should I Use?; Video Signal Flow Chart; Audio Signal Flow Chart
22 Connecting the AV receiver —Continued By connecting both the audio and video outputs of your DVD player and other AV components to the AV receiver, you can switch the audio and video signals simultaneously simply by changing the input source on the AV receiver. The AV receiver supports several co...
Page 23 - About HDMI; , so TVs and displays; About Copyright Protection; Connecting Components with HDMI
23 Connecting the AV receiver —Continued About HDMI Designed to meet the increased demands of digital TV, HDMI (High Definition Multimedia Interface) is a new digital interface standard for connecting TVs, projectors, DVD/BD players, set-top boxes, and other video components. Until now, several sepa...
Page 24 - Audio Signals; on, otherwise no HDMI signal will be output.; Making HDMI Connections
24 Connecting the AV receiver —Continued If you have an HDMI-compatible player, you can connect it to the AV receiver with an HDMI cable. ■ Audio Signals • Audio and video signals received via inputs other than the HDMI IN jacks are not output by the HDMI OUT. • Audio and video signals received via ...
Page 25 - Connecting a TV or Projector; Step 1: Video Connection
25 Connecting the AV receiver —Continued • With connection , you can listen to and record audio from your TV. • To enjoy Dolby Digital and DTS, use connection or . If your TV has no audio outputs, connect an audio output from your VCR or cable or satellite receiver to the AV receiver and use its tun...
Page 26 - Connecting a DVD/BD player
26 Connecting the AV receiver —Continued • With connection , you can listen to and record audio from a DVD. • To enjoy Dolby Digital and DTS, use connection or . (To record as well, use and , or and .) • If your DVD/BD player has main left and right outputs and multichannel left and right outputs, b...
Page 27 - Connecting a VCR or DVR for Playback
27 Connecting the AV receiver —Continued With this hookup, you can use the tuner in your VCR or DVR to listen to your favorite TV programs via the AV receiver, which is useful if your TV has no audio outputs. • To enjoy Dolby Digital and DTS, use connection or . Connecting a VCR or DVR for Playback ...
Page 28 - Connecting a VCR or DVR for Recording; Make the video connection; Step 2: Audio Connection; Make the audio connection
28 Connecting the AV receiver —Continued Notes: • The AV receiver must be turned on for recording. Recording is not possible while it’s on Standby.• If you want to record directly from your TV or another video source without going through the AV receiver, connect the audio and video outputs from you...
Page 30 - Connecting a Portable Audio player; Step 1: Make the audio connection
30 Connecting the AV receiver —Continued Connecting a Portable Audio player Connection AV receiver Signal flow Portable Audio Player AUX INPUT PORTABLE Analog audio Line output AUX INPUT PORTABLE AUDIO LINE OUT a Step 1: Make the audio connection . a Portable Audio Player a
Page 31 - Turntable with an MC (Moving Coil) Cartridge; Connecting a CD Player or Turntable
31 Connecting the AV receiver —Continued ■ CD Player or Turntable (MM) with Built-in Phono Preamp • With connection , you can listen to and record audio from the CD player. • To connect the CD player digitally, use connection or . ■ Turntable (MM) with no Phono Preamp Built-in A phono preamp is nece...
Page 32 - • With connection; Choose a connection that matches your recorder (
32 Connecting the AV receiver —Continued • With connection , you can play and record. • To connect the recorder digitally for playback, use connections and , or and . Connecting a Cassette, CDR, MiniDisc, or DAT Recorder Connection AV receiver Signal flow Cassette, CDR, MD, or DAT recorder TV/TAPE I...
Page 33 - If Your iPod Supports Video:; Connecting an RI Dock; • Connect the RI Dock to the AV receiver with an
33 Connecting the AV receiver —Continued ■ If Your iPod Supports Video: Connect your RI Dock’s audio output jacks to the AV receiver’s CBL/SAT IN or VCR/DVR IN L/R jacks, and connect its video output jack to the AV receiver’s CBL/SAT IN or VCR/DVR IN V jack. ■ If Your iPod Doesn’t Support Video: Con...
Page 34 - Auto Power On/Standby; Connecting Onkyo
34 Connecting the AV receiver —Continued With u (Remote Interactive), you can use the following special functions: ■ Auto Power On/Standby When you start playback on a component connected via u , if the AV receiver is on Standby, it will automatically turn on and select that component as the input s...
Page 35 - Turning On the AV receiver; Turning On and Standby; Up and Running in a Few Easy Steps; If you did, see “Changing the Input Display” on page 37.
35 Turning On the AV receiver ON/STANDBY ON/STANDBY RECEIVER STANDBY indicator Turning On and Standby On the AV receiver, press the [ON/STANDBY] button. On the remote controller, press the [RECEIVER] button, followed by the [ON/STANDBY] button. The AV receiver comes on, the display lights up, and th...
Page 36 - First Time Setup; Component Video Input Setup; Use the Up and Down [; Digital Input Setup
36 First Time Setup If you connect to a COMPONENT VIDEO IN, you must assign it to an input selector. For example, if you connect your DVD/BD player to COMPONENT VIDEO IN 2, you should assign it to the DVD/BD input selector. Note: This procedure can also be performed on the AV receiver by using its [...
Page 37 - Changing the Input Display
37 First Time Setup —Continued Notes: • Make sure you also set your digital sources to send out a digital signals. Please refer to the digital sources’ manual. • This procedure can also be performed on the AV receiver by using its [SETUP] button, arrow buttons, and [ENTER] button. If you connect an ...
Page 38 - Basic Operations; Basic AV receiver Operation; Speaker Set B; Start playback on the source component.; See “Using the Listening Modes” on page 47.
38 Basic Operations Basic AV receiver Operation 1 Use the AV receiver’s input selector buttons to select an input source. To select an input source with the remote controller, Press the [RECEIVER] button, and then press its INPUT SELECTOR buttons. 2 To turn the speakers on or off, use the AV receive...
Page 39 - You can adjust the brightness of the display.; To unmute the AV receiver,; press the remote; To cancel the sleep timer,; repeatedly until the SLEEP indicator disappears.; To check the remaining sleep time,; Setting the Display Brightness; Muting the AV receiver
39 Basic Operations —Continued This section explains functions that can be used with any input source. You can adjust the brightness of the display. You can temporarily mute the output of the AV receiver. To unmute the AV receiver, press the remote controller’s [MUTING] button again, or adjust the v...
Page 40 - Bass; Using Headphones; Displaying Source Information
40 Basic Operations —Continued 7 For private listening, you can connect a pair of stereo headphones (1/4-inch phone plug) to the AV receiver’s PHONES jack. Notes: • Always turn down the volume before connecting your headphones. • While the headphones plug is inserted in the PHONES jack, the speakers...
Page 41 - • If noise is produced when fast forwarding or; Using the Music Optimizer
41 Basic Operations —Continued The Music Optimizer function enhances the sound quality of compressed music files. Use it with music files that use “lossy” compression, such as MP3. Note: The Music Optimizer function only works with PCM digital audio input signals with a sampling rate below 48 kHz an...
Page 42 - Listening to the Radio; AM/FM Frequency Step Setup; Use the Left and Right [
42 Listening to the Radio For AM/FM tuning to work properly, you must specify the AM/FM frequency step used in your area. Note that when this setting is changed, all radio presets are deleted. Note: This procedure can also be performed on the AV receiver by using its [SETUP] button, arrow buttons, a...
Page 43 - Tuning into AM/FM Radio Stations; Auto Tuning Mode; Listening to AM/FM Stations
43 Listening to the Radio —Continued With the built-in tuner, you can enjoy AM and FM radio stations and store your favorite stations as presets for easy selection. Tuning into AM/FM Radio Stations ■ Auto Tuning Mode When tuned into a station, the TUNED indicator appears. When tuned into a stereo FM...
Page 44 - Tuning into Stations by Frequency; Displaying AM/FM Radio Information
44 Listening to the Radio —Continued ■ Tuning into Stations by Frequency You can tune into AM and FM stations directly by entering the appropriate frequency. Displaying AM/FM Radio Information 1 Press the [AM] or [FM] button to select “AM” or “FM”, followed by the [D.TUN] button. (Actual display dep...
Page 45 - Deleting Presets; Presetting AM/FM Stations; The preset number flashes.; select a preset from 1 through 40.; See the next section.
45 Listening to the Radio —Continued You can store a combination of up to 40 of your favorite AM and FM radio stations. Deleting Presets Selecting Presets Presetting AM/FM Stations 1 Tune into the AM or FM station you want to store as a preset. 2 Press the [MEMORY] button. The preset number flashes....
Page 46 - Recording; • The surround sound and DSP listening modes cannot; Recording the Input Source; Prepare the VCR for recording.
46 Recording This section explains how to record the input source and how to record audio and video from separate sources. Notes: • The surround sound and DSP listening modes cannot be recorded. • Copy-protected DVDs cannot be recorded.• Sources connected to a digital input cannot be recorded. Only ...
Page 47 - Using the Listening Modes; Selecting on the AV receiver; Selecting the Listening Modes; • The Dolby Digital and DTS listening modes can
47 Using the Listening Modes For a description of each listening mode, see “About the Listening Modes” on page 51. Selecting on the AV receiver ■ [MOVIE/TV] button This button selects the listening modes intended for use with movies and TV. ■ [MUSIC] button This button selects the listening modes in...
Page 48 - Mono/Multiplex Sources; : Available Listening Modes; Listening Modes Available for Each Source Format
48 Using the Listening Modes —Continued Mono/Multiplex Sources ✔ : Available Listening Modes Listening Modes Available for Each Source Format The Speaker layout illustration shows which speakers are set to active in the “Sp Config” setting (see page 52). The LISTENING MODE button illustration shows ...
Page 49 - Stereo Source
49 Using the Listening Modes —Continued Stereo Source ✔ : Available Listening Modes Listening Mode Button Speaker layout Direct ✔ ✔ ✔ Stereo ✔ ✔ ✔ Mono ✔ ✔ ✔ PLII Movie ✔ ✔ PLII Music ✔ ✔ PLII Game ✔ ✔ Neo:6 Cinema ✔ ✔ Neo:6 Music ✔ ✔ Orchestra ✔ Unplugged ✔ Studio-Mix ✔ TV Logic ✔ Game-RPG ✔ Game-A...
Page 50 - Multichannel Sources
50 Using the Listening Modes —Continued Multichannel Sources ✔ : Available Listening Modes Listening Mode Button Speaker layout Direct ✔ ✔ ✔ Stereo ✔ ✔ ✔ Mono ✔ ✔ ✔ Dolby Digital/DTS/DTS 96/24 ✔ ✔ Orchestra ✔ Unplugged ✔ Studio-Mix ✔ TV Logic ✔ Game-RPG ✔ Game-Action ✔ Game-Rock ✔ Game-Sports ✔ AllC...
Page 51 - Use this mode when playing game discs.; Onkyo Original DSP Modes; Use this mode when playing role playing game discs.; About the Listening Modes
51 Using the Listening Modes —Continued The AV receiver’s listening modes can transform your listening room into a movie theater or concert hall, with high fidelity and stunning surround sound. Direct In this mode, audio from the input source is output directly with minimal processing, providing hig...
Page 52 - Advanced Setup; Common Procedures in Setup Menu; Speaker Settings; Large; Subwoofer
52 Advanced Setup Note: This procedure can also be performed on the AV receiver by using its [SETUP] button, arrow buttons, and [ENTER] button. This section explains how to check the speaker settings and how to set them manually. Common Procedures in Setup Menu SETUP RECEIVER qwer ENTER NumberButton...
Page 53 - This setting only applies to the speakers that you specified as “; Double Bass; Double Bass function off.; Unit
53 Advanced Setup —Continued Crossover (Crossover Frequency) This setting only applies to the speakers that you specified as “ Small ” in the “3. Sp Config” on page 52. To get the best bass performance from your speaker system, you need to set the crossover frequency according to the size and freque...
Page 54 - EQ
54 Advanced Setup —Continued 5. Level Cal (Speaker Levels Calibration) You can set the volume level of each speaker so that all speakers can be heard equally at the listening position. A pink noise test tone is output by the front left speaker. Notes: • Speakers that you set to “No” or “None” in the...
Page 55 - Audio Adjust Settings; Multiplex/Mono Settings
55 Advanced Setup —Continued With the Audio Adjust functions and settings, you can adjust the sound and listening modes as you like. Audio Adjust Settings 7. Audio Adjust Multiplex/Mono Settings Input (Mux) Main: The main channel is output (default). Sub: The sub channel is output. M/S: Both the mai...
Page 56 - Audyssey Settings
56 Advanced Setup —Continued Audyssey Settings Audyssey EQ™ is based on the same core technology as Audyssey MultEQ ® that is used for automatic correction of room acoustics. Audyssey EQ uses time-domain filters to correct problems that arise from speaker drivers and enclosures and is calibrated to ...
Page 57 - This section explains items on the Hardware menu.; Hardware Setup; Remote ID; The Remote indicator flashes twice.; Tuner; See “AM/FM Frequency Step Setup” on page 42.
57 Advanced Setup —Continued This section explains items on the Hardware menu. T-D (Theater-Dimensional) Setting LstnAngl (Listening Angle) Wide: Select if the listening angle is 40 degrees (default). Narrow: Select if the listening angle is 20 degrees. With this setting, you can optimize the Theate...
Page 58 - Using the Audio Settings; Repeat this step for the other settings.; Tone Control Settings; Small reduction in dynamic range.; CinemaFILTER
58 Advanced Setup —Continued You can change various audio settings by pressing the [AUDIO] button. Using the Audio Settings RECEIVER AUDIO qwer 1 Press the [RECEIVER] button followed by the [AUDIO] button. 2 Use the Up and Down [ q ]/[ w ] buttons to select an item. 3 Use the Left and Right [ e ]/[ ...
Page 59 - Audyssey Dynamic VolumeTM; See “Dyn Vol (Dynamic Volume)” of “Audio Adjust Settings” on page 56.; Music Optimizer; Music Optimizer on.; Speaker Levels
59 Advanced Setup —Continued Audyssey Dynamic Volume™ Dyn Vol See “Dyn Vol (Dynamic Volume)” of “Audio Adjust Settings” on page 56. EX.BASS EX.BASS is a technology that have developed by experiments and listening tests to reproduce a natural deeper bass.When you turn the mode on, you can get dynamic...
Page 60 - Onkyo RI Dock with; Entering Remote Control Codes; The codes are organized by category.
60 Controlling Other Components You can control your DVD player, CD player, and other components with the AV receiver’s remote controller.To control another component, you must first enter that component’s remote control code to a REMOTE MODE button.This section explains how to enter remote control ...
Page 61 - Resetting the REMOTE MODE Buttons; cable and an; Resetting the Remote Controller
61 Controlling Other Components —Continued Remote Control Codes for Onkyo Components Connected via u Onkyo components that are connected via u are controlled by pointing the remote controller at the AV receiver, not the component. This allows you to control components that are out of view, in a rack...
Page 62 - Controlling a DVD Player, or DVD Recorder
62 Controlling Other Components —Continued By pressing the REMOTE MODE button that’s been programmed with the remote control code for your DVD player (HD DVD, Blu-ray, or TV/DVD combination), you can control your player with the following buttons. The [DVD/BD] button is preprogrammed with the remote...
Page 63 - Controlling a CD Player, CD Recorder, or MD Player
63 Controlling Other Components —Continued By pressing the REMOTE MODE button that’s been programmed with the remote control code for your CD player, CD recorder, or MD player, you can control your player with the following buttons. The [CD] button is preprogrammed with the remote control code for c...
Page 64 - When Using an RI Dock:; Controlling an RI Dock
64 Controlling Other Components —Continued By pressing the REMOTE MODE button that’s been programmed with the remote control code for your RI Dock, you can control your iPod in the RI Dock with the following buttons. The [DOCK] button is preprogrammed with the remote control code for controlling an ...
Page 65 - PLAY MODE button; Rewind and Fast Forward [; Controlling a Cassette Recorder
65 Controlling Other Components —Continued r PLAY MODE button Selects play modes on components with selectable play modes.Works as a Resume button when used with a DS-A2 RI Dock. s RANDOM button* Used with the shuffle function. * Buttons marked with an asterisk ( * ) are not supported by 3rd generat...
Page 66 - Troubleshooting; Power
66 Troubleshooting If you have any trouble using the AV receiver, look for a solution in this section. If you can’t resolve the issue yourself, contact your Onkyo dealer. Can’t turn on the AV receiver • Make sure that the power cord is plugged into the wall outlet properly. • Unplug the power cord f...
Page 68 - Can’t control other components
68 Troubleshooting —Continued • If the AV receiver is installed in a rack or cabinet with colored-glass doors, the remote controller may not work reliably when the doors are closed. • Make sure you’ve selected the correct remote controller mode (pages 13 and 62–65). • Make sure to set the same ID on...
Page 69 - Specifications; Amplifier Section; Video Inputs
69 Specifications Amplifier Section Video Section Tuner Section General ■ Video Inputs ■ Video Outputs ■ Audio Inputs ■ Audio Outputs Specifications and features are subject to change without notice. Rated Output Power All channels: 110 watts minimum continuous power per channel, 6 ohm loads, at 1kH...
Page 70 - ch Home Theater Speaker Package
70 Specifications —Continued 5.1ch Home Theater Speaker Package ■ Passive Subwoofer (SKW-370) ■ Front Speaker (SKF-370) ■ Center Speaker (SKC-370) ■ Center Speaker (SKC-370C) ■ Surround Speaker (SKR-370) Specifications and features are subject to change without notice. Type: Bass-reflex type Passive...
Page 71 - Memo