# Harsh static/noise at beginning of calls when Background Sound is enabled **URL:** \ **Category:** Support Help\ **Tags:** telephony\ **Created:** [September 6, 2026, 2:12pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615 "2026-09-06T14:12:31Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![adam1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/adam1/32/2610_2.png) [@adam1](https://community.retellai.com/u/adam1)\ **Post date:** [September 6, 2026, 2:12pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/1 "2026-09-06T14:12:31Z")
Has anyone else recently started experiencing a harsh static/distorted audio burst at the beginning of Retell phone calls when Background Sound is enabled? My agents were working normally a couple of weeks ago, but recently I started hearing a very unpleasant burst of static/interference immediately after the call connects, before the agent begins speaking. I did several A/B tests and found that the issue appears to be related to Retell’s Background Sound feature: - Background Sound enabled → harsh startup noise - Tried multiple background sounds → issue occurs with all of them, although some are worse than others - Tried several background sound volume levels → issue remains - Background Sound volume set to 0 → noise disappears - Background Sound set to None → noise disappears I initially suspected Twilio/SIP/network quality, but the issue is reproducible and consistently disappears when Retell Background Sound is disabled. Has anyone else noticed this recently? I’m especially curious whether this could be a recent change/regression in Retell’s background-audio mixing or whether certain carriers/codecs are having trouble with the background audio. If you’ve experienced this, did you find a solution other than disabling Background Sound? ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 7, 2026, 12:08pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/2 "2026-09-07T12:08:24Z")
Hey @adam1 Thanks for the detailed A/B testing and reproduction steps. Since the issue consistently occurs only when Background Sound is enabled, Could you please share a recent **Call ID** where the static/noise occurred? Best Regards. ---
**Author:** ![adam1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/adam1/32/2610_2.png) [@adam1](https://community.retellai.com/u/adam1)\ **Post date:** [September 7, 2026, 6:04pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/3 "2026-09-07T18:04:32Z")
Thanks, Mark. I’ve provided two recent Call IDs for comparison: - One call with Background Sound enabled, where the harsh static/noise occurs at the beginning. - One call with Background Sound disabled, where the startup noise does not occur. Hopefully comparing the two calls helps isolate the issue. Please let me know if you need any additional Call IDs or testing from my side. call\_6f6e87b4be98eea0dc7f761a2be call\_00c8a1039424714a3c485a70649 ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 7, 2026, 6:20pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/4 "2026-09-07T18:20:15Z")
Hey @adam1 I’ve escalated your request to the relevant team. As soon as I receive an update from them, I’ll let you know promptly. Thank you for your patience. Best Regards. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 9, 2026, 12:45pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/5 "2026-09-09T12:45:30Z")
Hey @adam1 Thanks for your patience. We reviewed the separate audio channels and found that the agent’s speech track is clear, while the startup noise appears on the incoming caller audio track. We’ve attached both recordings for reference. The left channel contains caller audio, and the right channel contains the agent’s speech. Could you try one call with Background Sound enabled and another with it disabled while using headphones, and let us know whether you still hear the noise? If it persists, could you share a recording of what you hear on the receiving phone, along with the call IDs? Recordings : [Recordings - Google Drive](https://drive.google.com/drive/folders/1LnPDeDyWwy1_MVISlR5OY9S17TucxQFk?usp=drive_link) Best Regards. ---
**Author:** ![adam1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/adam1/32/2610_2.png) [@adam1](https://community.retellai.com/u/adam1)\ **Post date:** [September 12, 2026, 11:51am UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/6 "2026-09-12T11:51:18Z")
Hi Mark, sorry for the delay. I completed the additional A/B test using headphones as requested. With Background Sound enabled, the harsh startup noise is still present and is very loud through the headphones. With Background Sound disabled, there is no startup noise at all. Both tests were performed using the same receiving phone/headphones and setup, with Background Sound being the only setting changed between the calls. I’ve included the Call IDs for both tests and a Google Drive link of what I’m actually hearing on the receiving phone when Background Sound is enabled. Hopefully this helps narrow it down. Background Sound ON: call\_8d5bee9da677c6e00eaa6f2f7b1 Background Sound OFF: call\_62260afc34e0356b6bbe0b0368f > **[call with static noise at start.m4a](https://drive.google.com/file/d/1pL_cWCTDfDo3inDnj551hdBSGcTbqkjO/view?usp=sharing)** > > Google Drive file. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 12, 2026, 1:02pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/7 "2026-09-12T13:02:07Z")
Hi @adam1 Thanks for completing the additional tests and sharing the Call IDs. I’m checking this with the relevant team now. As soon as I receive any update, I’ll let you know promptly. Thank you for your patience. Best Regards. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 14, 2026, 2:04pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/8 "2026-09-14T14:04:46Z")
Hey @adam1 Team just tried to call your agent, and could not reproduce the harsh startup noise. Could you share a few details about your test setup? What phone, calling app, and carrier are you using? Does it also happen when calling from a different phone or network? Best Regards. ---
**Author:** ![adam1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/adam1/32/2610_2.png) [@adam1](https://community.retellai.com/u/adam1)\ **Post date:** [September 14, 2026, 9:54pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/9 "2026-09-14T21:54:52Z")
Hi Mark, Thanks for checking into this. My test setup is an iPhone on the AT&T cellular network, using the standard iPhone Phone app. I also tested from a second iPhone and was able to reproduce the same harsh startup noise. That phone was also on the AT&T network, so I haven’t yet tested from a different carrier/network. On both devices, the behavior has been consistent: with Background Sound enabled, I hear the harsh startup noise; with Background Sound disabled, the noise is not present. For now, I’m fine keeping Background Sound disabled on these agents, so this isn’t preventing me from moving forward. I mainly wanted to report it since the behavior appears consistently tied to enabling Background Sound on my end. If it would be helpful for troubleshooting, I can also test from a different carrier/network when I have access to one. Thanks again for looking into it. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 15, 2026, 12:38pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/10 "2026-09-15T12:38:44Z")
Hey @adam1 Thanks for the additional details and for running the tests on multiple devices. I’m checking this with the relevant team now. As soon as I receive any update, I’ll let you know promptly. Thank you for your patience. Best Regards. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 15, 2026, 12:43pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/11 "2026-09-15T12:43:00Z")
Hey @adam1 We reviewed the audio stream in the packet capture for the call and didn’t hear the harsh startup noise in that capture. We’ve reproduced it on AT&T but haven’t reproduced it on Verizon so far. Attached the audio stream screenshots for call\_8d5bee9da677c6e00eaa6f2f7b1. (first is what we received, second is what we sent.) From the screenshot, we can confirm that the sharp voice is not from out end. This suggests it may be related to carrier. For now, if the issue is still there and consistent, keeping Background Sound disabled is a reasonable workaround. Best Regards. ![image](https://canada1.discourse-cdn.com/flex008/uploads/retell1/original/2X/4/4398d211b71edaff7e1eefbd5fbe1937d17036a3.jpeg) ![image](https://canada1.discourse-cdn.com/flex008/uploads/retell1/original/2X/8/8fd4567d9df3de1aa99228e70e1432755d093397.png) ---
**Author:** ![adam1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/adam1/32/2610_2.png) [@adam1](https://community.retellai.com/u/adam1)\ **Post date:** [September 15, 2026, 1:17pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/12 "2026-09-15T13:17:28Z")
Hi Mark, Thanks for the detailed investigation. That makes sense, and it’s helpful to know that your team was also able to reproduce the issue on AT&T but not Verizon. For now, I’m comfortable keeping Background Sound disabled on these agents since that completely eliminates the issue and allows me to move forward. I appreciate you and the team taking the time to reproduce it and review the packet captures. If you end up identifying anything further regarding the AT&T behavior, I’d definitely be interested in the findings. Thanks again for looking into this. ---
**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\ **Post date:** [September 15, 2026, 2:33pm UTC](https://community.retellai.com/t/harsh-static-noise-at-beginning-of-calls-when-background-sound-is-enabled/3615/13 "2026-09-15T14:33:40Z")
Hey @adam1 Thanks for the detailed update. I’m glad you have a temporary workaround by keeping Background Sound disabled. I’ll keep an eye on this with the team and let you know if we receive any further findings regarding the AT&T behavior. Thanks again for your patience and for helping us troubleshoot this. Best Regards.