5 Replies Latest reply on Nov 29, 2019 2:53 AM by AnjanaM_61

    a2dp sink noise




      I tested the A2DP sink function using "snip.bt.a2dp_sink" in WICED-Studio-6.4.


      Program to CYBT-343026-01, connect the I2S output to the DAC (NXP UDA1334A), and output to the headset for playback.


      The sound output has a noise, once every four seconds, pronounced like "po".


      I have tried programming to CYW920706WCDEVAL and the situation is the same.


      Is there any experience in solving this? What parameters can be improved?

        • 1. Re: a2dp sink noise



          Can you please confirm the sampling frequency DAC is tuned to ?

          Please note the frequencies supported by 20706 is 44.1 & 48 KHz as mentioned here: PCM/I2S Clock setting in CYW20706


          Can you please check and confirm?




          • 2. Re: a2dp sink noise



            I tried to switch A2D_SBC_IE_SAMP_FREQ_44 and A2D_SBC_IE_SAMP_FREQ_48, only 44.1KHz can be played.

            I think it is working at 44.1kHz.


            I tested the BT_AUDIO_A2DP_SBC_MAX_BITPOOL parameter and I adjusted it to 16~40.

            The noise is changed once every four seconds and becomes non-periodic noise (about 3 noises in 1 minute).



            *   codec and audio tuning configurations


            /*  Recommended max_bitpool for high quality audio */

            #define BT_AUDIO_A2DP_SBC_MAX_BITPOOL   53


            /* Array of decoder capabilities information. */

            wiced_bt_a2dp_codec_info_t bt_audio_codec_capabilities[] =



                    .codec_id = WICED_BT_A2DP_CODEC_SBC,

                    .cie =


                        .sbc =


            //                (A2D_SBC_IE_SAMP_FREQ_44 | A2D_SBC_IE_SAMP_FREQ_48),    /* samp_freq */

                            (A2D_SBC_IE_SAMP_FREQ_44),                                /* pairing success and playback */

            //                (A2D_SBC_IE_SAMP_FREQ_48),                              /* cannot pair device */

                            (A2D_SBC_IE_CH_MD_MONO   | A2D_SBC_IE_CH_MD_STEREO |

                             A2D_SBC_IE_CH_MD_JOINT  | A2D_SBC_IE_CH_MD_DUAL),      /* ch_mode */

                            (A2D_SBC_IE_BLOCKS_16    | A2D_SBC_IE_BLOCKS_12 |

                             A2D_SBC_IE_BLOCKS_8     | A2D_SBC_IE_BLOCKS_4),        /* block_len */

                            (A2D_SBC_IE_SUBBAND_4    | A2D_SBC_IE_SUBBAND_8),       /* num_subbands */

                            (A2D_SBC_IE_ALLOC_MD_L   | A2D_SBC_IE_ALLOC_MD_S),      /* alloc_mthd */

                            BT_AUDIO_A2DP_SBC_MAX_BITPOOL,                          /* max_bitpool for high quality audio */

                            A2D_SBC_IE_MIN_BITPOOL                                  /* min_bitpool */





            • 3. Re: a2dp sink noise

              Hi Felix Tang,


              Can you please confirm if the noise issue is still there?

              We had tested the same A2DP sink example with another codec as mentioned in the blog :WICED Studio Bluetooth Forums

              But there was no noise issue.

              I think you may have to check on the codec configurations which you are using.




              • 4. Re: a2dp sink noise

                Hi Anjana,


                The noise problem exists on CYW920706WCDEVAL and CYBT-343026-01.

                I tried to move the original a2dp_sink to 20719-B1_Bluetooth (EVB: CYW920719Q40EVB_01) and the noise problem disappeared.


                I want to use the Azurewave AW-BT304(CYW20719) instead.

                However, there are distinctions between CYW20719-B1 (wiced) and CYW20719-B2 (modus). With CYW20719-B2 developed by MODUS, is there an example of "a2dp sink"?

                • 5. Re: a2dp sink noise

                  Hi Felix Tang,


                  I am sorry , unfortunately we are not promoting CYW20719 B1/ B2 for Audio profiles. Only A2DP source is supported.

                  Our Audio solutions are CYW20706 and CYW20721 modules .

                  Please contact your local FAE for the details.



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