AnsweredAssumed Answered

Hiss and Squeal on SGTL5000 via I2S

Question asked by Eugene Tyler on Nov 14, 2014
Latest reply on Nov 25, 2014 by Fabio Estevam

We are having problems with background hiss and a squealing sound when

playing sound through a KITSGTL5000EVBE connected to an i.mx6 MCU.  After

the actual sound plays, the hiss becomes more evident and a squealing

sound is heard that changes frequency until the SGTL5000 is powered down

by Alsa.  The i.MX6, which is housed on a MSC Q7 module, is running Linux

3.0.35 built from Yocto Dora with the MSC BSP layer.  Other than changes

to direct the I2c control traffic to the correct muxed output, there are

no changes to sgtl5000.c or imx-sgtl5000.c. 


To eliminate the possibility of the hiss and squeal being present on the

I2S data line, the i.MX6 I2S Data out line was disconnected and the

SGTL5000 I2S Data In was shorted to ground.  This did not reduce the hiss

or squeal. 


We use aplay to duplicate this issue, which occurs every time we play

any sound. For example: aplay Side_Left.wav


Has anyone experienced undesired sound artifacts when using the SGTL5000,

especially in the KITSGTL500EVBE?  If so, what steps did you take to

resolve the issue?