What Is Sidetone? CW Pitch, Rig Menus, and Headset Mic Monitoring

Sidetone means two different things, and this site is named after one of them

Type "sidetone" into a search bar and you'll land in one of two different worlds. In Morse code (CW) operation, sidetone is the tone a transceiver plays back to the operator's own ears every time the key goes down — how a CW operator hears what they're sending, independent of whether the signal is actually reaching the air. In telephony and headsets, sidetone is the deliberate feedback of your own microphone audio into your own earpiece or ear cups, so a caller doesn't feel like they're shouting into a void. Both meanings share one root idea — hearing your own transmitted audio, routed back to you locally — and both matter if you operate CW, use a headset for calls, or both.

In CW, sidetone is the tone you hear while you key

When a CW operator presses a key or paddle, the transceiver does two things at once: it keys the transmitter (so the signal goes out over the air), and it generates a locally produced audio tone fed to the operator's speaker or headphones. That second part is the sidetone. According to Wikipedia's entry on the topic, in amateur radio and wireless telegraphy, sidetone provides audible feedback of a continuous-wave signal as the operator sends Morse code, serving as feedback to the operator that what they are sending is what they intended.

This matters for a few reasons. Sidetone is diagnostic — uneven spacing, an off keyer weight, or a sticking paddle contact usually shows up in the sidetone before it's ever noticed on the air. Kenwood's TS-590S manual makes the same point, noting you can use the sidetone to confirm that your key contacts are closing and the keyer is functioning, or to practice sending without putting a signal on the air. And because a radio's sidetone and its receive audio typically share the same pitch, matching the two is normal operating practice, not a cosmetic preference.

Why CW pitch matters — matching your sidetone to your receive offset

A receiver tuned to the exact frequency of an incoming CW signal — "zero beat" — would produce a tone at 0 Hz, which is inaudible. Yaesu's FT-891 Advance Manual explains the fix plainly: "the receiver is offset several hundred Hz (typically), to produce a beat tone that can be heard. The BFO offset associated with this tuning (that produces the comfortable audio tone) is called the CW Pitch." On many rigs that same tone doubles as the transmit sidetone: Kenwood's TS-590S manual states that "the frequency of the sidetone and RX pitch are equal and selectable," and Elecraft's KX2 manual says its sidetone pitch "is also the pitch of CW signals when centered in the receiver's passband" — change one, and you change both.

Practically, this means an operator who sets their sidetone/pitch to, say, 600 Hz will also hear incoming signals at roughly 600 Hz once properly tuned in — a deliberately comfortable, consistent reference tone rather than an arbitrary beep. Elecraft's KX2 manual notes that "500-700 Hz is typically used with headphones," though the manufacturer-published adjustable ranges run considerably wider, as the table below shows.

Sidetone menu names and ranges on three widely used rigs

Every manufacturer names and ranges this control a little differently, and the control for pitch (frequency) is often split from the control for volume (level). The specifics below come straight from each maker's own manual.

A few things stand out once you line these up. All three published ranges sit inside roughly 300–1050 Hz. All three also separate the pitch control from the level (volume) control — on the FT-891 and TS-590S that's a distinct menu item with its own name ("MONITOR" and "Sidetone volume"); on the KX2 it's the same physical knob repurposed, with a tap to switch functions. None of the three labels the control simply "tone" — all three menu names include the word "pitch."

Sidetone level vs. "monitor" — same idea, different labels

If you've moved between brands, the terminology mismatch is one of the more confusing parts of CW setup. Elecraft's KX2 Owner's Manual describes the shared control directly: "Tapping the knob switches its function to MON (monitor volume level). In CW mode, this turns on the sidetone... In SSB mode, you'll hear your microphone audio." In other words, on that rig, "monitor" is simply the generic name for "how loud is the feedback audio," whether that feedback happens to be a CW sidetone or your own SSB voice.

Yaesu's FT-891 Advance Manual uses "MONITOR" the same way for CW: "The CW sidetone audio level may be adjusted by setting 'MONITOR.'" Kenwood's TS-590S menu, by contrast, spells out "Sidetone volume" as its own named setting, distinct from the "CW RX pitch/TX sidetone frequency" entry that sets the tone itself. None of this changes what the control does — it's always a volume knob for the tone in your ear — but it explains why a menu-diving operator moving from an Elecraft rig to a Kenwood one might go looking for "MON" and come up empty.

QSK, semi break-in, and how your sidetone behaves

Sidetone's behavior changes depending on how your transceiver handles transmit/receive switching. In full break-in, commonly called QSK, the radio is fast enough to switch back to receive in the tiny gaps between individual dots and dashes. As Wikipedia's entry on QSK operation describes it, QSK is "an operating mode in which the transmitting station can detect signals from other stations between the elements (dots and dashes) or letters of the Morse transmission" — meaning another station can, in principle, interrupt you mid-character, and you'd hear it.

Semi break-in is slower by design. Rather than switching on every element, a semi break-in radio holds the transmitter keyed for a short "hang time" after you stop sending, then drops back to receive. Yaesu's FT-891 Advance Manual frames this hang time as "the functional equivalent of the 'VOX Delay' adjustment used on voice modes," adjustable from 30 milliseconds to 3 seconds on that rig, with a 200 ms default. You'll still hear your own sidetone normally while sending during that hang time — what changes is how quickly the receiver comes back afterward. The Wikipedia QSK article notes that a semi break-in station, relying on VOX-style switching timed for human speech, "simply cannot hear in the short duration between the Morse code signals and words" — full break-in's entire value is closing that gap.

Practice oscillators: sidetone without a radio

Sidetone isn't exclusive to transceivers. A code practice oscillator is essentially a sidetone generator with no transmitter attached — a small box with a key jack, a tone circuit, and a speaker, built purely so a learner can hear their own sending without putting a signal on the air. MFJ's classroom-oriented MFJ-554, for instance, is described on its product page as producing "a true pure sinewave sidetone with no trace of harsh keyclicks," with a "400-1000 Hz tone control" and a separate volume control — the same pitch-versus-level split found on full transceivers, just packaged for practice rather than operating. For a beginner working through code speed before ever keying a transmitter, a practice oscillator's sidetone is functionally identical to what they'll hear on a rig later — the same feedback loop, minus the radio. If you're building code speed from scratch, a structured path through the fundamentals covers the practice-oscillator stage in more depth.

Sidetone in telephones and headsets: hearing your own voice

Outside of amateur radio, "sidetone" describes something nearly everyone has experienced without naming it. Wikipedia's sidetone article defines the general concept plainly: sidetone is "audible feedback to someone speaking or otherwise producing sound as an indication of active transmission." In a telephone handset specifically, that means "sound picked up by the telephone's transmitter (mouthpiece) and instantly introduced at a low electronic signal level into the receiver (earpiece)" of the same handset — a small, deliberate echo of your own voice, mixed in at low volume.

The amount of sidetone a phone injects is tuned, not accidental. The same Wikipedia entry puts typical land-line sidetone at 8% and cellular at 4% (a figure it flags as needing a citation), and notes that too much sidetone can cause users to speak softly. Too little sidetone and talkers tend to raise their voice, a behavior the article says is sometimes called "cell yell"; and because sidetone is expected, its absence can make users believe the call has been dropped.

Mic monitoring on gaming and office headsets

The same idea shows up under a more casual name on modern headsets: mic monitoring. Corsair's own explainer on the feature describes sidetone as a function where "the audio captured from the microphone, i.e. your voice, is rebroadcast through the earcups back to you in real-time." Corsair gives two reasons manufacturers build this in. One is volume control — hearing your own voice through a closed headset makes it obvious when you've started talking too loudly for the room, which Corsair says matters as much for not disturbing roommates as for not shouting down a voice-chat server. The other is comfort: closed-back headsets and ear cups muffle outside sound, including your own voice, in a way open-back headphones don't, and sidetone restores some of that natural self-awareness so speaking doesn't feel disorienting.

The same logic applies to anyone wearing a headset for long calls: hearing your own voice makes it easier to keep your volume in check without lifting an ear cup. Whatever the product, the goal is the same feedback loop telephone handsets have offered for more than a century.

SSB voice monitor: the telephony meaning on your own transceiver

Amateur radio actually has a second, voice-mode version of sidetone that borrows directly from the telephone/headset concept rather than the CW one. On rigs like the Elecraft KX2, the same monitor control that sets CW sidetone volume also sets how much of your own microphone audio gets mixed into your headphones during SSB transmission — the manual's language above, "In SSB mode, you'll hear your microphone audio," is describing mic monitoring in the same sense a headset user would recognize. It serves the identical purpose: letting an operator judge their own speaking level, processing, or EQ settings in real time without a second receiver or a buddy on the other end giving a signal report. New operators sorting out their first station's audio chain — sidetone included — generally find it faster to work through a first-weekend setup guide than to reverse-engineer every menu alone.

FAQ

Is sidetone the same thing as the signal I'm actually transmitting? No. Sidetone is generated locally by the transceiver (or, for voice modes, mixed in from the microphone circuit) and fed only to the operator's own speaker or headphones — it tells you what you're sending, not what the other station is hearing. The actual over-the-air signal depends on your antenna, power, and propagation, none of which sidetone reflects.

Why do CW sidetone and receive pitch usually move together? Because on many rigs it is one shared setting — Kenwood's TS-590S manual, for example, says the sidetone and RX pitch frequencies "are equal and selectable." As Yaesu's FT-891 manual explains, a receiver tuned to exact zero beat on an incoming signal would produce an inaudible 0 Hz tone, so the receiver is offset by several hundred Hz to produce a tone you can actually hear.

Can I turn sidetone off entirely? On most transceivers and practice oscillators, yes — sidetone volume typically has an OFF or minimum setting, as seen in Kenwood's TS-590S "Sidetone volume" menu (OFF, or 1–9). Operators monitoring an external speaker sometimes turn it off, though beginners are better served leaving it on while learning.

Why does my headset's sidetone sound delayed or echoey? One common cause is where the mic signal is being mixed back in: monitoring routed through the connected computer or phone's audio software, rather than handled in the headset itself, can add a noticeable delay. If your headset offers a sidetone or "mic monitoring" level setting, lowering it — or checking whether your OS is adding its own separate monitoring on top of the headset's built-in version — is the usual fix.

Does a louder sidetone make my signal stronger? No. Sidetone volume is purely local feedback for the operator; it has no effect on transmitter power, modulation, or how the signal is received elsewhere. The only way to judge actual signal strength is a report from the receiving station, not how loud you sound in your own headphones.

Gear names, menu labels, and ranges above are drawn from each manufacturer's own published manual (checked October 2026); menus shift across firmware revisions, so confirm the current map against your rig's manual before relying on a setting name.