Quick Answer: HDMI ARC (Audio Return Channel) lets a projector send audio back to a soundbar or AV receiver over the same HDMI cable used for video, instead of running a separate optical or analog cable. Support is far from universal — per BenQ’s own compatibility chart, only select current models carry full ARC/eARC, while many budget and older projectors have no ARC port at all. If audio isn’t coming through, the fix is almost always the same: use the port specifically labeled ARC or eARC, confirm HDMI-CEC is turned on for both devices, and check the cable is certified for the bandwidth you need.
Most people assume any HDMI port handles audio return the same way it handles video, and that assumption is the source of nearly every “picture works, sound doesn’t” support thread. This guide covers what ARC and eARC actually do, which projectors realistically support it, and the exact troubleshooting order that fixes it fastest.
By the numbers: Per BenQ’s own projector-lineup compatibility table, support splits into three real tiers — full ARC 5.1 + eARC 7.1 + Dolby Atmos on current models like the X500i, X3100i, and TK700STi; ARC-only (5.1, no eARC) on models like the X1300i and GP500; and no ARC support at all on budget models like the TH685P and GV30. Separately, eARC’s HDMI 2.1 bandwidth is high enough to carry Dolby TrueHD and DTS-HD Master Audio, formats standard ARC’s 5.1-channel ceiling can’t pass through at all, per the same BenQ guidance.
ARC vs. eARC vs. your other options
| Connection | Max audio | Cable needed | Best for |
|---|---|---|---|
| HDMI eARC | 7.1ch + Dolby Atmos/DTS:X | Certified Ultra High Speed (HDMI 2.1) | Current soundbars/AVRs on a projector that supports it |
| HDMI ARC | 5.1ch surround | Certified High Speed w/ Ethernet | Older soundbars, projectors without eARC |
| Optical (TOSLINK) | 5.1ch compressed | Standard optical cable | Projectors with no ARC port at all |
| Bluetooth | Stereo, device-dependent | None | Portables, outdoor setups, no cable run possible |
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If your projector doesn’t have a labeled ARC port, don’t chase a workaround cable — TOSLINK optical or a direct source-to-soundbar connection (below) are the reliable fallbacks. Setting up the audio side of a new build in general? Our best external speakers for projectors guide covers every connection type, and our best HDMI cable for projector guide covers the video-side cable itself.
Why ARC support is so inconsistent on projectors
Unlike TVs, where ARC has been close to a standard feature for close to a decade, projectors treat it as a mid-to-high-tier feature. BenQ’s own current lineup makes the split explicit: full ARC-and-eARC support (with Dolby Atmos passthrough) is reserved for models like the X500i, X3100i, X300G, X3000i, TK700STi, and TK700; a middle tier including the X1300i, TH685i, and GP500 carries ARC only, capped at 5.1 with no eARC; and budget-focused models like the TH685P, GV30, GS2, and GV1 skip audio return entirely. On the Epson side, the Home Cinema 2350 does carry ARC, but only on its HDMI 1 port — HDMI 2 is dedicated to the projector’s bundled Android TV streaming stick, so plugging a soundbar into the wrong one is a genuinely easy mistake to make on that model specifically.
The practical takeaway: don’t assume. Check your exact model’s port labeling or spec sheet before buying a soundbar around the assumption that ARC will just work.
HDMI ARC not working? Fix it in this order
- Confirm you’re using the labeled port. Most projectors with ARC have exactly one port that carries it, usually marked “HDMI (ARC),” “HDMI eARC,” or something similar to BenQ’s “Audio Return+” labeling. Any other HDMI input on the same unit is video-only.
- Enable HDMI-CEC on both ends. ARC rides on top of the CEC handshake between devices — if CEC is disabled on the projector, the soundbar, or both, the return channel won’t negotiate even with the right port and cable. CEC is sometimes labeled by a brand name (Anynet+, SimpLink, Bravia Sync) rather than “CEC” outright.
- Check the cable spec. A certified High Speed HDMI cable with Ethernet covers standard ARC; eARC needs a certified Ultra High Speed cable built for HDMI 2.1 bandwidth. An older or uncertified cable is a well-documented cause of choppy audio or a silent fallback to lower-quality compressed sound.
- Set the audio output mode correctly. In the projector’s audio settings, select ARC or eARC as the output (rather than leaving it on internal speakers) and set the format to Auto — if problems persist, forcing PCM output is a common diagnostic step to isolate whether the issue is the connection or a specific audio format.
- Power-cycle both devices. Unplug the projector and the soundbar/receiver for about 30 seconds, then power them back on — this resolves a meaningful share of ARC handshake failures that follow a firmware update or a power outage, without changing any settings.
No ARC port on your projector at all
This is the honest answer for a lot of budget and older home theater projectors: if there’s no port labeled ARC or eARC anywhere on the unit, don’t spend money hunting for an adapter that promises to add it — it doesn’t exist as a reliable retrofit. Two options actually work. First, run optical (TOSLINK) instead, which is still common even on entry-level projectors and soundbars and carries up to 5.1-channel compressed audio with no CEC handshake required. Second, and often simpler, connect your source — a streaming stick, cable box, or game console — directly to the soundbar’s own HDMI input, then pass a second HDMI cable from the soundbar through to the projector for video only; the soundbar decodes and plays the audio itself rather than waiting for the projector to send it back. If neither wired option is realistic for your room layout, Bluetooth remains the no-cable fallback, at the cost of the roughly 100-200ms of lip-sync lag covered in our external speakers guide.
The bottom line
HDMI ARC and eARC let a projector send audio back to a soundbar over a single cable, but actual support varies enormously by model — check your specific projector’s labeled ports rather than assuming any HDMI input works, since BenQ’s own lineup alone splits into full support, ARC-only, and no support at all. If audio still won’t pass through, work the checklist in order: right port, CEC enabled, certified cable, correct output setting, then a power cycle. No ARC port on your unit? Optical or a direct source-to-soundbar connection both beat searching for an ARC adapter that doesn’t meaningfully exist. Building out a full audio setup from scratch? Our best external speakers for projectors guide covers every connection type in one place, and if you’re troubleshooting a smart projector’s network setup at the same time, our how to connect a projector to WiFi guide covers that separately.
Guidance verified August 2026 against manufacturer ARC/eARC documentation and subject to change; check your specific model’s spec sheet for exact port support.