因为音效均为几秒的音频，首先考虑了AudioToolbox，但是发现戴耳机会出现音量太小的问题。每次都需要重新再改变音量控制键才可以。因此，舍弃了AudioToolbox的音效播放方式。
以下为AVAudioPlayer播放音效：
代码取自https://github.com/owlcoding/SimpleAudioPlayer
在多组合音效做了简易修改：
下面为代码.h 部分

#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>

typedef void(^CompletionBlock)(BOOL);

@interface AVAudioPlayerWithCompletionBlock : AVAudioPlayer

@property (nonatomic, copy) CompletionBlock completionBlock;
@end

@interface HBAudioService : NSObject<AVAudioPlayerDelegate>{
    SystemSoundID soundID;
    int audioCount;
    NSURL *url;
    NSMutableSet *players;
}

@property (nonatomic, strong) AVAudioPlayer *player;
@property (nonatomic, strong) NSArray *audioFile;
@property (nonatomic,assign) NSInteger currentIndex;
@property(nonatomic,assign)SystemSoundID audioSoundID;//播放文件标识

+ (HBAudioService *)shared;

/*
 The method
 + (AVAudioPlayer *) playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops withCompletionBlock:(CompletionBlock)completion;
 
 the loops parameter works like this:
 any negative number - sound keeps playing in a loop over and over
 0, 1 - sound is played once
 2, 3, etc - sound is played twice, 3 times, etc-times :)
 */
+ (AVAudioPlayer *) playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops withCompletionBlock:(CompletionBlock)completion;

/*
 The methods below just call the
 playFile: volume: loops: withCompletionBlock:
 */
+ (AVAudioPlayer *)playFile:(NSString *)name;
+ (AVAudioPlayer *)playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops;
+ (AVAudioPlayer *) playFile:(NSString *)name withCompletionBlock:(CompletionBlock)completion ;

+ (AVAudioPlayer *) playLoopedFile:(NSString *) name;

+ (void)stopPlayer:(AVAudioPlayer *)player;
+ (void)stopAllPlayers;
+ (void) playFiles:(NSArray *) filesList withCompletionBlock:(CompletionBlock) completion;

@end

下面为.m部分

#import "HBAudioService.h"
@implementation AVAudioPlayerWithCompletionBlock

@end

static HBAudioService *_manger = nil;
@implementation HBAudioService

static HBAudioService *sharedInstance = nil;

+ (void)initialize
{
    if (sharedInstance == nil)
        sharedInstance = [[self alloc] init];
}

+ (HBAudioService *)shared
{
    //Already set by +initialize.
    return sharedInstance;
}

+ (id)allocWithZone:(NSZone*)zone
{
    //Usually already set by +initialize.
    @synchronized(self) {
        if (sharedInstance) {
            //The caller expects to receive a new object, so implicitly retain it
            //to balance out the eventual release message.
            return sharedInstance;
        } else {
            //When not already set, +initialize is our caller.
            //It's creating the shared instance, let this go through.
            return [super allocWithZone:zone];
        }
    }
}

- (id)init
{
    //If sharedInstance is nil, +initialize is our caller, so initialize the instance.
    //If it is not nil, simply return the instance without re-initializing it.
    if (sharedInstance == nil) {
        self = [super init];
        if (self) {
            //Initialize the instance here.
            players = [NSMutableSet setWithCapacity:1];
            self.currentIndex = 0;
        }
    }
    return self;
}


- (AVAudioPlayer *) playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops withCompletionBlock:(CompletionBlock)completion
{
    NSString *filePath = [[NSBundle mainBundle] pathForResource:name ofType:nil];
    if(!filePath) {
        return nil;
    }
   
    NSError *error = nil;
    NSURL *fileURL = [NSURL fileURLWithPath:filePath isDirectory:NO];
    AVAudioPlayerWithCompletionBlock *player = [[AVAudioPlayerWithCompletionBlock alloc] initWithContentsOfURL:fileURL error:&error];
    player.volume = vol;
    player.numberOfLoops = loops;
    // Retain and play
    if(player) {
        [players addObject:player];
        player.delegate = self;
        player.completionBlock = completion;
        [player play];
        return player;
    }
    return nil;
    
}


- (void) playFiles:(NSArray*) filesList withCompletionBlock:(CompletionBlock) completion
{
    if (self.currentIndex < filesList.count) {
        [self playFile:filesList[self.currentIndex] withCompletionBlock:^(BOOL completed) {
            if (self.currentIndex < filesList.count) {
                self.currentIndex++;
                [self playFiles:filesList withCompletionBlock:completion];
            }else {
                if (completion) {
                    completion(YES);
                }
            }
        }];
    }
}


- (AVAudioPlayer *)playFile:(NSString *)name {
    
    return [self playFile:name volume:1.0f loops:0 withCompletionBlock:nil];
}
- (AVAudioPlayer *) playLoopedFile:(NSString *) name {
    return [self playFile:name volume:1.0f loops:-1];
}
- (AVAudioPlayer *) playFile:(NSString *)name withCompletionBlock:(CompletionBlock)completion
{
    return [self playFile:name volume:1.0f loops:0 withCompletionBlock:completion];
}

- (AVAudioPlayer *)playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops {
    
    return [self playFile:name volume:vol loops:loops withCompletionBlock:nil];
}


- (void)stopPlayer:(AVAudioPlayer *)player {
    if([players containsObject:player]) {
        player.delegate = nil;
        [players removeObject:player];
        [player stop];
    }
}

- (void)stopAllPlayers {
    NSSet *pls = [NSSet setWithSet:players];
    for (AVAudioPlayer *p in pls) {
        [self stopPlayer:p];
    }
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayerWithCompletionBlock *)player successfully:(BOOL)completed {
    
    if (player.completionBlock) {
        player.completionBlock ( completed );
    }
    player.delegate = nil;
    [players removeObject:player];
}

- (void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error {
    //TRC_DBG(@"audioPlayerDecodeErrorDidOccur %@", error);
    player.delegate = nil;
    [players removeObject:player];
}

+ (AVAudioPlayer *)playFile:(NSString *)name {
    return [[HBAudioService shared] playFile:name];
}

+ (AVAudioPlayer *)playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops {
    return [[HBAudioService shared] playFile:name volume:vol loops:loops];
}
+ (AVAudioPlayer *) playFile:(NSString *)name withCompletionBlock:(CompletionBlock)completion
{
    return [[HBAudioService shared] playFile:name withCompletionBlock:completion];
}
+ (AVAudioPlayer *) playFile:(NSString *)name volume:(CGFloat)vol loops:(NSInteger)loops withCompletionBlock:(CompletionBlock)completion
{
    return [[HBAudioService shared] playFile:name volume:vol loops:loops withCompletionBlock:completion];
}
+ (AVAudioPlayer *) playLoopedFile:(NSString *) name
{
    return [[HBAudioService shared] playLoopedFile:name];
}
+ (void)stopPlayer:(AVAudioPlayer *)player {
    return [[HBAudioService shared] stopPlayer:player];
}
+ (void)stopAllPlayers {
    return [[HBAudioService shared] stopAllPlayers];
}
+ (void) playFiles:(NSArray *)filesList withCompletionBlock:(CompletionBlock)completion
{
    [[HBAudioService shared] playFiles:filesList withCompletionBlock:completion];
}