Direct answer
For the Bose QuietComfort Earbuds II, output routing, volume/mute, app, Bluetooth profile and cable/HDMI path should be separated. First, select the device explicitly and play a system test tone.
What this covers
- Bose QuietComfort Earbuds II (870730)
- Bose product; Bluetooth multipoint, app generation, wired input and spatial/ANC features vary.
- The specific fault this record addresses: connects but has no sound
What it does not cover
- ×The same symptom on a different Bose product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
Audio is routed elsewhere
What separates it The accessory shows as connected while sound plays from the phone or another device.
How to confirm Connection and audio routing are separate. Select the accessory explicitly as the output.
- 2
The volume is at zero on one of several controls
What separates it Silence with the volume apparently up, where the accessory has its own volume separate from the source.
How to confirm Many accessories keep an independent volume level. Raise both.
- 3
The audio format is not supported
What separates it Silence on specific content only, typically Dolby Atmos or DTS.
How to confirm Set the source's output to PCM or stereo as a test. If sound returns, the format was the problem.
- 4
The device is connected in the wrong Bluetooth profile
What separates it Silence, or very poor quality, with a call application running.
How to confirm A headset switches to a low-bandwidth two-way profile when a microphone is in use. Quitting the call application entirely restores playback.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Whether the accessory is selected as the audio output, as opposed to merely being connected.
- Whether silence affects everything or only specific content, which points at audio format.
- Which input a soundbar is set to.
- Whether a call application is running.
Select the accessory explicitly as the audio output
ReversibleConnection and routing are separate; a paired device can sit silent while audio goes elsewhere.
Raise the volume on both the source and the accessory
ReversibleMany accessories keep an independent volume level from the device driving them.
Set the source's audio output format to PCM or stereo as a test
ReversibleIf sound returns, a surround format was being sent that the accessory cannot decode.
Test with a different source device
ReversibleThis separates the accessory from the phone, computer or television driving it.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- 870730. Bose product; Bluetooth multipoint, app generation, wired input and spatial/ANC features vary.
- Type — ANC Bluetooth earbuds (battery)
- Bose's standard flagship-ANC earbuds (no Immersive Audio — that is the Ultra) with a charging case. Battery/ANC/Bluetooth and earbud-specific symptoms (fit, tips, case contacts) apply.
- Fit & CustomTune
- Fit bands plus ear tips, with CustomTune calibration at insertion; ANC and bass depend on the seal, so wrong-sized tips/bands are the usual cause of thin sound or weak ANC.
- Case & battery
- Buds charge in the case; dirty case contacts leave a bud starting low. ANC on at high volume shortens runtime.
- Power path
- Internal or removable battery. Every capability that costs current — night vision, higher stream quality, longer recordings, frequent events — is paid for in runtime, so a change in behaviour after a settings change is usually a power consequence rather than a fault. Cold weather reduces usable capacity sharply.
- Symptom boundary
- This record covers Bose QuietComfort Earbuds II when it connects but has no sound. A different symptom on the same hardware, or this symptom on a different Bose product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !Stop for distortion accompanied by heat, or any burning smell.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. Bose Support publishes this as "QuietComfort Earbuds II: no audio from product". Bose's own article for this symptom on this product. The title here is read from the article's URL slug: support.bose.com serves the <title> "Customer Support" on every page, so there is no published title to copy. Probed 2026-08-23: 200 against a hard-404 control, which is what discriminates on this host. What that article does not carry is the model boundary — it is written for a product line, and 870730 is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
One of my Bose QC Earbuds II won't charge in the case.+
Clean the charging contacts — earwax and lint on the bud's contacts and the matching pins in the case are the common cause of one bud not charging, so wipe both with a dry cotton bud. Make sure the bud seats fully in its slot (a magnet should pull it in). If a bud still will not charge or connect, reset the earbuds per Bose's steps and re-pair. The buds also pair to each other, so a dropped link between them can leave one silent.
It says connected but there's no sound.+
Connecting and being selected as the output are two different things, and a device can be connected while audio continues to play elsewhere. Open the sound output settings and select the accessory explicitly. If that is already right, set the source's audio format to PCM or stereo as a test — silence on specific content only is almost always a surround format the accessory cannot decode.
Does this answer apply to every Bose model?+
No. It is scoped to 870730. Bose product; Bluetooth multipoint, app generation, wired input and spatial/ANC features vary.
What should I record before troubleshooting no sound or connected?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing no sound, connected. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Stop for electrical noise, heat, sparks or severe distortion.
Answer for the exact device and software version shown above.