Yamaha YPG-635 User Manual

Owner’s ManualENKeyboard Stand AssemblyFor information on assembling the keyboard stand, refer to the instructions on page 10 of this manual.

10 DGX-630/YPG-635 Owner’s ManualSetting Upz The parts shown in the “Assembly Parts” illustration will be used. Follow the assemblyinstructions and s

100 DGX-630/YPG-635 Owner’s ManualSaving and Loading DataThis operation saves a user song (song numbers 031–035) to USB flash memory.1Make sure that a

DGX-630/YPG-635 Owner’s Manual 101Saving and Loading DataUser files as well as Style, Song, and Music Database files residing on a USB flash memory can

102 DGX-630/YPG-635 Owner’s ManualSaving and Loading DataThis procedure deletes User, Style, Song, and Music Database files from a USB flash memory.1Ma

DGX-630/YPG-635 Owner’s Manual 103Saving and Loading DataThis procedure deletes the User Song as well as Style, Song, and Music Database files transfe

Reference104 DGX-630/YPG-635 Owner’s ManualConnectionsq USB TO DEVICE terminalThis terminal allows connection to USB stor-age devices. Refer to “Prec

DGX-630/YPG-635 Owner’s Manual 105ConnectionsThe following functions become available when this instrument is connected to a computer.● Performance d

106 DGX-630/YPG-635 Owner’s ManualConnectionsBy connecting the instrument to a computer, the instrument’s performance data can be used on the com-put

DGX-630/YPG-635 Owner’s Manual 107Connections PC Mode ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● A number of MIDI settings need to be

108 DGX-630/YPG-635 Owner’s ManualConnectionsThis function lets you send the panel setup data to a computer. Before you record performance data to a

DGX-630/YPG-635 Owner’s Manual 109Connections Use Musicsoft Downloader To Transfer Songs From the Accessory CD-ROM To the Instrument’s flash memory ●

DGX-630/YPG-635 Owner’s Manual 11Setting Upx Attach the stand bases.Insert the joint connectors q into the stand boards as shown. The joint connector

110 DGX-630/YPG-635 Owner’s ManualConnections8Close the window to end the Musicsoft Downloader.9To playback a song stored in flash memory, press the [

ReferenceDGX-630/YPG-635 Owner’s Manual 111Accessory CD-ROM Installation Guide• The software and this manual are the exclusive copyrights of Yamaha C

112 DGX-630/YPG-635 Owner’s ManualAccessory CD-ROM Installation GuideIn order to view PDF scores, you will need to install Adobe Reader in your compu

DGX-630/YPG-635 Owner’s Manual 113Accessory CD-ROM Installation Guide Installing the USB-MIDI Driver● ● ● ● In order to be able to communicate

114 DGX-630/YPG-635 Owner’s ManualAccessory CD-ROM Installation GuideInstalling the driver on Windows 20001Start the computer and use the “Adminis-tr

DGX-630/YPG-635 Owner’s Manual 115Accessory CD-ROM Installation Guide10When using Windows XP Professional x64 Edition, the Support Module must be ins

116 DGX-630/YPG-635 Owner’s ManualAccessory CD-ROM Installation Guide Troubleshooting• Is the USB cable connected correctly?Check the USB cable conne

DGX-630/YPG-635 Owner’s Manual 117Accessory CD-ROM Installation Guide[Windows 2000/XP/Vista]1 Start the computer and use the “Adminis-trator” account

118 DGX-630/YPG-635 Owner’s ManualTroubleshooting For the InstrumentProblem Possible Cause and SolutionWhen the instrument is turned on or off, a po

DGX-630/YPG-635 Owner’s Manual 119TroubleshootingThe appropriate display does not appear when the [SONG], [EASY SONG ARRANGER], [STYLE], or [VOICE] b

12 DGX-630/YPG-635 Owner’s ManualSetting Upb Put the keyboard on the stand.Check the back-to-front orientation for stand, and care-fully place the ke

120 DGX-630/YPG-635 Owner’s ManualMessagesLCD Message CommentAccess error!Indicates the failure in reading or writing from/to the media or the flash m

DGX-630/YPG-635 Owner’s Manual 121MessagesOverCurrentCommunication with the USB device has been shut down because of the overcurrent to the USB devic

122 DGX-630/YPG-635 Owner’s ManualScoresThis demo is an example of how the Easy Song Arranger can be used to change styles throughout a piece.Hallelu

ScoresDGX-630/YPG-635 Owner’s Manual 123

Scores124 DGX-630/YPG-635 Owner’s ManualThis score is provided with the intent that the pitch will be corrected by the performance assistant technol-

ScoresDGX-630/YPG-635 Owner’s Manual 125

Scores126 DGX-630/YPG-635 Owner’s ManualThis score is provided with the intent that the pitch will be corrected by the performance assistant technol-

ScoresDGX-630/YPG-635 Owner’s Manual 127

128 DGX-630/YPG-635 Owner’s ManualVoice List Maximum Polyphony ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● The instrument has 64-note maxi

Voice ListDGX-630/YPG-635 Owner’s Manual 129● XGlite Voice/XGlite Optional Voice* List098 000 113 062 Big Band Brass099 000 113 063 80’s Brass100 000

DGX-630/YPG-635 Owner’s Manual 13Setting UpBe sure to do the following operations BEFORE turning on the power. Make sure that the [STANDBY/ON] switc

Voice List130 DGX-630/YPG-635 Owner’s Manual227 000 032 027 Jazz Amp228 000 000 028 Clean Guitar229 000 032 028 Chorus Guitar230 000 000 029 Muted Gu

Voice ListDGX-630/YPG-635 Owner’s Manual 131The voice number with an asterisk (*) is XGlite optional voice.366 000 035 087 Big Five367 000 000 088 Ba

132 DGX-630/YPG-635 Owner’s ManualDrum Kit List•“ ” indicates that the drum sound is the same as “Standard Kit 1”.• Each percussion voice uses one

Drum Kit ListDGX-630/YPG-635 Owner’s Manual 133Voice No. 131 137 138 139 140 141 142MSB (0–127) / LSB (0–127) / PC (1–128) 127/000/001 127/000/113 12

134 DGX-630/YPG-635 Owner’s ManualStyle ListStyle No. Style Name8BEAT1 ChartPianoPop2 BritPopRock3 8BeatModern4 Cool8Beat5 Classic8Beat6 60’sGuitarPo

DGX-630/YPG-635 Owner’s Manual 135Music Database ListMDB No. MDB NameALL TIME HITS1 Jude Hey2 New UK3 MyLoving4 All OK5 Buttercp6 JustCall7 CheepChp8

136 DGX-630/YPG-635 Owner’s ManualSongs Provided On the Supplied CD-ROMThe easy song arranger can only be used with songs that include chord data. Fi

DGX-630/YPG-635 Owner’s Manual 137Harmony Type ListNo. Harmony Type Description1 01(Standard Duet)Harmony types 01–10, 13 are pitch-based and add one

138 DGX-630/YPG-635 Owner’s ManualEffect Type List● Reverb Types● Chorus TypesNo. Type Description MSB LSB1 HALL1Reverb simulating the acoustics of a

Effect Type ListDGX-630/YPG-635 Owner’s Manual 139● DSP TypesNo. Type Description MSB LSB1 HALL1Reverb simulating the acoustics of a hall.102 HALL2 1

14 DGX-630/YPG-635 Owner’s ManualSetting UpThis jack is for connecting an optional LP-7 pedal unit. When connecting the pedal unit, make sure to also

Effect Type List140 DGX-630/YPG-635 Owner’s Manual60 SYMPHONIC1Adds more stages to the modulation of Celeste.68 1661 SYMPHONIC2 68 062ENS DETUNE(Ense

Effect Type ListDGX-630/YPG-635 Owner’s Manual 14199OD+DELAY1(Overdrive + Delay1)Overdrive and Delay are connected in series.95 17100OD+DELAY2(Overdr

Effect Type List142 DGX-630/YPG-635 Owner’s Manual134EP TC WAH(EP Touch Wah)EP Touch Wah 82 19135WH+DST+DLY1(Wah + Distortion + Delay1)Wah, Distortio

Effect Type ListDGX-630/YPG-635 Owner’s Manual 143171 EQ DISCOEqualizer effect that boosts both high and low frequencies, as is typi-cal in most disc

144 DGX-630/YPG-635 Owner’s ManualMIDI Implementation Chart YAMAHA [ Portable Grand ] Date:14-MAY-2007Model DGX-630

MIDI Implementation ChartDGX-630/YPG-635 Owner’s Manual 145Prog o 0 - 127 o 0 - 127Change : True # **************System Exclusive o o : Song

146 DGX-630/YPG-635 Owner’s ManualMIDI Data FormatNOTE:1 By default (factory settings) the instrument ordinarily functions as a 16-channel multi-timb

DGX-630/YPG-635 Owner’s Manual 147ATTENTIONSOFTWARE LICENSE AGREEMENTPLEASE READ THIS SOFTWARE LICENSE AGREEMENT (“AGREE-MENT”) CAREFULLY BEFORE USIN

148 DGX-630/YPG-635 Owner’s ManualSIBELIUS SCORCH LICENSE AGREEMENTBy installing and/or using this Product you (an individual or legal entity) agree

DGX-630/YPG-635 Owner’s Manual 149SpecificationsKeyboards• 88 Graded Hammer Standard keys (A-1–C7), with Touch Response.Display• 320 x 240 dots LCD di

DGX-630/YPG-635 Owner’s Manual 15Setting UpConnect the instrument’s USB terminal to the USB ter-minal of a computer, and you can transfer performance

150 DGX-630/YPG-635 Owner’s Manual+/– ... 16, 67 ...

IndexDGX-630/YPG-635 Owner’s Manual 151Measure ... 69Melody ...

152 DGX-630/YPG-635 Owner’s ManualLimited Warranty90 DAYS LABOR 1 YEAR PARTSYamaha Corporation of America, hereafter referred to as Yamaha, warrants

For details of products, please contact your nearest Yamaha representative or the authorized distributor listed below.Pour plus de détails sur les pro

U.R.G., Pro Audio & Digital Musical Instrument Division, Yamaha Corporation© 2007 Yamaha Corporation WM92600 XXXPOXXX.X-01A0 Printed in ChinaY

16 DGX-630/YPG-635 Owner’s ManualPanel Controls and Terminalsq [STANDBY/ON] switch ...page 15w [MASTER VOLUME] control ...

DGX-630/YPG-635 Owner’s Manual 17Panel Controls and Terminals#6 CONTRAST knob ...page 69#7 USB TO DEVICE terminal...

18 DGX-630/YPG-635 Owner’s ManualQuickGuideChanging the Display LanguageThis instrument allows you to select English or Japanese as the display langu

DGX-630/YPG-635 Owner’s Manual 19QuickGuideTry Playing a Variety of Instrument VoicesIn addition to piano, organ, and other “standard” keyboard instr

2 DGX-630/YPG-635 Owner’s ManualPLEASE KEEP THIS MANUALThis product utilizes batteries or an external power supply (adapter). DO NOT connect this pro

Try Playing a Variety of Instrument Voices20 DGX-630/YPG-635 Owner’s ManualYou can select a second voice which will play in addition to the main voic

Try Playing a Variety of Instrument VoicesDGX-630/YPG-635 Owner’s Manual 214Play the keyboard.Try selecting and playing a range of dual voices.Press

Try Playing a Variety of Instrument Voices22 DGX-630/YPG-635 Owner’s Manual3Select the desired split voice.Watch the highlighted split voice and rota

DGX-630/YPG-635 Owner’s Manual 23Fun SoundsThis instrument includes a range of drum kits and unique sound effects you can use for entertainment. Laug

24 DGX-630/YPG-635 Owner’s ManualQuickGuideThe MetronomeTurn the metronome on and start it by pressing the [MET-RONOME ON/OFF] button.To stop the met

The MetronomeDGX-630/YPG-635 Owner’s Manual 25In this example we’ll set up a 5/8 time signature.1Press and hold the [METRONOME ON/OFF] button for lon

The Metronome26 DGX-630/YPG-635 Owner’s ManualThis allows you to select whether the click sound has a bell accent, or plays only a click sound.1Press

DGX-630/YPG-635 Owner’s Manual 27QuickGuidePlaying StylesThis instrument has an auto accompaniment feature that produces accompaniment (rhythm + bass

Playing Styles28 DGX-630/YPG-635 Owner’s ManualYou learned how to select a style rhythm on the preceding page.Here we’ll see how to add bass and chor

Playing StylesDGX-630/YPG-635 Owner’s Manual 29When sync start is on, the bass and chord accompaniment included in a style will start playing as soon

DGX-630/YPG-635 Owner’s Manual 31. IMPORTANT NOTICE: DO NOT MODIFY THIS UNIT!This product, when installed as indicated in the instructions con-taine

Playing Styles30 DGX-630/YPG-635 Owner’s ManualStyles Are More Fun When You Understand ChordsChords, created by playing multiple notes at the same ti

Playing StylesDGX-630/YPG-635 Owner’s Manual 31—3-chord boogie-woogie—This progression provides varied harmonic backing with just three chords. When

Playing Styles32 DGX-630/YPG-635 Owner’s ManualThere are two ways of playing auto-accompaniment chords:● Easy Chords● Standard ChordsThe instrument w

DGX-630/YPG-635 Owner’s Manual 33QuickGuideUsing SongsWith this instrument the term “song” refers the data that makes up a piece of music. You can si

Using Songs34 DGX-630/YPG-635 Owner’s Manual3Listen to the song.Press the [START/STOP] button to begin playback of the selected song.You can stop pla

Using SongsDGX-630/YPG-635 Owner’s Manual 35Press the [DEMO] button.The demo song will start playing. Listen to some of the outstanding instrument vo

Using Songs36 DGX-630/YPG-635 Owner’s ManualThe following three types of songs can be used by the DGX-630/YPG-635.● Preset Songs (the 30 songs built

Using SongsDGX-630/YPG-635 Owner’s Manual 37This instrument is capable of display the scores of songs.Scores are displayed for the 30 internal preset

Using Songs38 DGX-630/YPG-635 Owner’s ManualIf a song contains lyric data, the lyrics can be made to appear on the display.No lyrics will be displaye

DGX-630/YPG-635 Owner’s Manual 39QuickGuideThe Easy Way to Play PianoThis instrument includes a performance assistant technology feature that lets yo

4 DGX-630/YPG-635 Owner’s Manual(3)-11 1/2PRECAUTIONSPLEASE READ CAREFULLY BEFORE PROCEEDING* Please keep this manual in a safe place for future ref

The Easy Way to Play Piano40 DGX-630/YPG-635 Owner’s Manual1Press the [P.A.T. ON/OFF] button.This turns on the performance assistant technology featu

The Easy Way to Play PianoDGX-630/YPG-635 Owner’s Manual 414Press the [START/STOP] button.Song playback will begin.The basic pattern will play repeat

The Easy Way to Play Piano42 DGX-630/YPG-635 Owner’s Manual1Press the [P.A.T. ON/OFF] button.This turns on the performance assistant technology featu

The Easy Way to Play PianoDGX-630/YPG-635 Owner’s Manual 434Press the [START/STOP] button.Song playback will begin.The left-hand keys you should play

The Easy Way to Play Piano44 DGX-630/YPG-635 Owner’s ManualSee page 48 for some hints on how to play melodies.1Press the [P.A.T. ON/OFF] button.This

The Easy Way to Play PianoDGX-630/YPG-635 Owner’s Manual 454Press the [START/STOP] button.Song playback will begin.Because the Melody type has been s

The Easy Way to Play Piano46 DGX-630/YPG-635 Owner’s Manual1Press the [P.A.T. ON/OFF] button.This turns on the performance assistant technology featu

The Easy Way to Play PianoDGX-630/YPG-635 Owner’s Manual 474Press the [START/STOP] button.Song playback will begin.The basic pattern will repeat. Lis

The Easy Way to Play Piano48 DGX-630/YPG-635 Owner’s ManualUse the Performance Assistant to Play Like a Pro!Here are a few hints for using the Chord

The Easy Way to Play PianoDGX-630/YPG-635 Owner’s Manual 49Make Use of the Score in the Melody Type.If you want to play the melody with the correct r

DGX-630/YPG-635 Owner’s Manual 5• Before connecting the instrument to other electronic components, turn off the power for all components. Before turn

50 DGX-630/YPG-635 Owner’s ManualLesson Flow:Select a song from the Piano Solo, Piano Ensemble category!The practice methods:● Lesson 1 ...

Select a Song For a LessonDGX-630/YPG-635 Owner’s Manual 51In this lesson, try playing the correct notes. Play the note shown in the display. The son

Select a Song For a Lesson52 DGX-630/YPG-635 Owner’s Manual4Start Lesson 1.Press the LESSON [START] button to select Lesson 1. Each time the LESSON [

Select a Song For a LessonDGX-630/YPG-635 Owner’s Manual 535Stop the Lesson modeYou can stop the Lesson mode at any time by pressing the [START/STOP]

Select a Song For a Lesson54 DGX-630/YPG-635 Owner’s ManualLearn to play the correct notes with the correct timing. Song playback tempo will vary to

Select a Song For a LessonDGX-630/YPG-635 Owner’s Manual 55Here’s where you can perfect your technique. The song will play at the normal tempo, minus

Select a Song For a Lesson56 DGX-630/YPG-635 Owner’s ManualUse this feature when you want to start again just ahead of a section on which you made a

DGX-630/YPG-635 Owner’s Manual 57QuickGuidePlay Using the Music DatabaseYou want to play music in your favorite style, but you’re not sure how to sel

58 DGX-630/YPG-635 Owner’s ManualQuickGuideChange a Song’s StyleIn addition to each song’s default style, you can select any other style to play the

Change a Song’s StyleDGX-630/YPG-635 Owner’s Manual 593Listen to the song.Press the [START/STOP] button to begin playback of the song. Move on to the

6 DGX-630/YPG-635 Owner’s ManualThe followings are the titles, credits and copyright notices for three (3) of the songs pre-installed in this electro

60 DGX-630/YPG-635 Owner’s ManualQuickGuideRecord Your Own PerformanceYou can record up to 5 of your own performances and save them as user songs 031

Record Your Own PerformanceDGX-630/YPG-635 Owner’s Manual 611From the MAIN display press the [SONG] button, then use the dial to select the user song

Record Your Own Performance62 DGX-630/YPG-635 Owner’s Manual3Recording will start when you play on the keyboard.You can also start recording by press

Record Your Own PerformanceDGX-630/YPG-635 Owner’s Manual 636When the recording is done ...◆ To Play Back a User SongUser songs are played back in th

Record Your Own Performance64 DGX-630/YPG-635 Owner’s Manual3Press the [+] button to clear the song.The clear-in-progress message will appear briefly

DGX-630/YPG-635 Owner’s Manual 65Backup and InitializationThe following settings are always backed up, and are maintained even when the power is turn

66 DGX-630/YPG-635 Owner’s ManualBasic OperationOverall DGX-630/YPG-635 control is based on the following simple operations.1 Press a button to selec

Basic OperationDGX-630/YPG-635 Owner’s Manual 672 Use the dial to select an item or valueWhen you select a basic function, the item corresponding to

Basic Operation68 DGX-630/YPG-635 Owner’s Manual● Display NamesAll operations are carried out while watching the display. A number of display types a

Basic OperationDGX-630/YPG-635 Owner’s Manual 69The MAIN display shows all of the current basic settings: song, style, voice.It also includes a range

DGX-630/YPG-635 Owner’s Manual 7Congratulations and thank you for purchasing the Yamaha DGX-630/YPG-635 Portable Grand!Please read this owner’s manua

Reference70 DGX-630/YPG-635 Owner’s ManualPlay with a Variety of EffectsThis feature adds harmony notes to the main voice.1Press the [HARMONY ON/OFF]

DGX-630/YPG-635 Owner’s Manual 71Play with a Variety of EffectsReverb lets you play with a rich concert hall type ambience.When you select a style or

72 DGX-630/YPG-635 Owner’s ManualPlay with a Variety of EffectsThe chorus effect creates a thick sound that is similar to many of the same voices bei

DGX-630/YPG-635 Owner’s Manual 73Play with a Variety of EffectsDSP is term of abbreviated form of Digital Signal Processor. The DSP effect can be add

74 DGX-630/YPG-635 Owner’s ManualPlay with a Variety of EffectsThis function adds sustain to the keyboard voices. Use it when you want to add sustain

ReferenceDGX-630/YPG-635 Owner’s Manual 75Handy Performance FeaturesYou can start the song/style by simply tapping the [TEMPO/TAP] button at the requ

76 DGX-630/YPG-635 Owner’s ManualHandy Performance FeaturesSometimes selecting the ideal voice to play with a song or style can be confusing. The One

DGX-630/YPG-635 Owner’s Manual 77Handy Performance FeaturesFive different master equalizer (EQ) settings are provided to give you the best possible s

78 DGX-630/YPG-635 Owner’s ManualHandy Performance Features◆ Large Pitch Changes (Transpose)The overall pitch of the instrument can by shifted up or

ReferenceDGX-630/YPG-635 Owner’s Manual 79Style (Auto-accompaniment) FunctionsBasic operation of the Style (auto-accompaniment) feature is described

8 DGX-630/YPG-635 Owner’s ManualSpecial Features of the DGX-630/YPG-635Graded Hammer Standard KeyboardThanks to our experience as the world’s leading

80 DGX-630/YPG-635 Owner’s ManualStyle (Auto-accompaniment) Functions1Press the [STYLE] button and then select a style.2Press the [ACMP ON/OFF] butto

DGX-630/YPG-635 Owner’s Manual 81Style (Auto-accompaniment) Functions7Press the [MAIN/AUTO FILL] button.When the fill-in is finished, it leads smoothly

82 DGX-630/YPG-635 Owner’s ManualStyle (Auto-accompaniment) FunctionsThe initial default split point is key number 54 (the F#2 key), but you can chan

DGX-630/YPG-635 Owner’s Manual 83Style (Auto-accompaniment) FunctionsWhen auto accompaniment is on (the ACMP ON icon is showing) and Synchro Start is

84 DGX-630/YPG-635 Owner’s ManualStyle (Auto-accompaniment) FunctionsTwo or more notes played together constitute a “chord”.The most basic chord type

DGX-630/YPG-635 Owner’s Manual 85Style (Auto-accompaniment) Functions Recognized Standard Chords● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

86 DGX-630/YPG-635 Owner’s ManualStyle (Auto-accompaniment) FunctionsIn “Play Along with a Style” on page 28 we described a method of playing styles

DGX-630/YPG-635 Owner’s Manual 87Style (Auto-accompaniment) FunctionsThe Dictionary function is essentially a built-in “chord book” that shows you th

Reference88 DGX-630/YPG-635 Owner’s ManualSong Settings1Press the [FUNCTION] button.2Use the CATEGORY [ ] and [ ] but-tons to select the Song Volume

DGX-630/YPG-635 Owner’s Manual 89Song SettingsEach “track” of a song plays a different part of the song—melody, percussion, accompaniment, etc. You c

DGX-630/YPG-635 Owner’s Manual 9Copyright Notice... 6Panel Logos ...

Reference90 DGX-630/YPG-635 Owner’s ManualMemorize Your Favorite Panel SettingsThis instrument has a Registration Memory feature that lets you save y

DGX-630/YPG-635 Owner’s Manual 91Memorize Your Favorite Panel Settings1Press the [MEMORY/BANK] button. A bank number will appear in the display when

Reference92 DGX-630/YPG-635 Owner’s ManualThe FunctionsThe “Functions” provide access to a range of detailed instrument parameters for tun-ing, setti

DGX-630/YPG-635 Owner’s Manual 93The Functions● Function Setting ListCategory Function Item Range/Settings DescriptionVOLUMEStyle Volume 000–127 Dete

94 DGX-630/YPG-635 Owner’s ManualThe FunctionsEFFECTReverb Type 01–30 Determines the Reverb type, including off. (See the list on page 138)Chorus Typ

DGX-630/YPG-635 Owner’s Manual 95The Functions* All these settings can be conveniently reset to their initial default values by pressing the [+] and

Reference96 DGX-630/YPG-635 Owner’s ManualSaving and Loading DataUSB flash memory is a memory medium used for storing data.When a USB flash memory is i

DGX-630/YPG-635 Owner’s Manual 97Saving and Loading Data Precautions when using the USB TO DEVICE terminalThis instrument features a built-in USB TO

98 DGX-630/YPG-635 Owner’s ManualSaving and Loading DataNew USB flash memory must be formatted before they can be used by this instrument. 1After

DGX-630/YPG-635 Owner’s Manual 99Saving and Loading DataThis operation saves a “User File” containing the registration memory data to a USB flash memo