[sake]

Found another solution. Sound after first respawn with short delay. But thanks anyways.

PHP Code:

#include <amxmodx>
#include <amxmisc>
#define VERSION "1.0"

new names[32][18]

public plugin_init()
{
    register_plugin("chi", VERSION, "sake")
    register_event("ResetHUD", "greetings", "be")
}

public greetings(id)
{
    new name[18] 
    get_user_name(id, name, 17)
    for(new i = 0; i < 31; i++)
    {
        if(strcmp(name,names[i],18) == 0)
        {
            return PLUGIN_CONTINUE
        }
    }
    set_task(0.2, "dummy", id)
    if(strcmp(name,"C.h.i",5) == 0)
    {
        names[id] = "C.h.i"
        client_cmd(0, "spk jnr/chi.wav")
        show_hudmessage(0,"Hallo, ich bin der C.h.i vom Teamspeak!")
    }
    else
    {
        names[id] = name
        new message[] = "Welcome on the Server, "
        strcat(message,name,100)
        strcat(message,"! Play fair!",112)
        show_hudmessage(0,message)
    }
    return PLUGIN_CONTINUE
}

public client_disconnect(id)
{
    names[id] = ""
    return PLUGIN_CONTINUE
}

public dummy(id)
{
    return PLUGIN_CONTINUE
}