stereo = runtime->channels == 2;
        w_16 = snd_pcm_format_width(runtime->format) == 16;
 
-       if (!extra && stereo) {
-               start_addr >>= 1;
-               end_addr >>= 1;
-       }
-       if (w_16) {
-               start_addr >>= 1;
-               end_addr >>= 1;
-       }
-
        spin_lock_irqsave(&emu->reg_lock, flags);
 
        /* volume parameters */
        struct snd_emu10k1 *emu = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_emu10k1_pcm *epcm = runtime->private_data;
+       bool w_16 = snd_pcm_format_width(runtime->format) == 16;
+       bool stereo = runtime->channels == 2;
        unsigned int start_addr, end_addr;
 
-       start_addr = epcm->start_addr;
-       end_addr = snd_pcm_lib_period_bytes(substream);
-       if (runtime->channels == 2) {
-               start_addr >>= 1;
-               end_addr >>= 1;
-       }
-       end_addr += start_addr;
+       start_addr = epcm->start_addr >> w_16;
+       end_addr = start_addr + runtime->period_size;
        snd_emu10k1_pcm_init_voice(emu, 1, 1, epcm->extra,
                                   start_addr, end_addr, NULL);
-       start_addr = epcm->start_addr;
-       end_addr = epcm->start_addr + snd_pcm_lib_buffer_bytes(substream);
+       start_addr >>= stereo;
+       end_addr = start_addr + runtime->buffer_size;
        snd_emu10k1_pcm_init_voice(emu, 1, 0, epcm->voices[0],
                                   start_addr, end_addr,
                                   &emu->pcm_mixer[substream->number]);
        struct snd_emu10k1 *emu = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_emu10k1_pcm *epcm = runtime->private_data;
-       unsigned int start_addr, end_addr;
+       unsigned int start_addr;
        unsigned int channel_size;
        int i;
 
-       start_addr = epcm->start_addr;
-       end_addr = epcm->start_addr + snd_pcm_lib_buffer_bytes(substream);
+       start_addr = epcm->start_addr >> 1;  // 16-bit voices
 
-       channel_size = ( end_addr - start_addr ) / NUM_EFX_PLAYBACK;
+       channel_size = runtime->buffer_size;
 
        snd_emu10k1_pcm_init_voice(emu, 1, 1, epcm->extra,
                                   start_addr, start_addr + (channel_size / 2), NULL);