Sound design
An equalizer that runs before the air, not after it.
macOS gives you no system-wide EQ, and nothing whatsoever between your Mac and an AirPlay speaker. SoundFerry puts a full studio chain there — 12 parametric bands, dynamics, width, limiting and real loudness metering — on everything the Mac plays.
The gap this fills
Search for a Mac equalizer and you will find plenty that work on your built-in speakers or your headphones. Search for one that shapes what leaves the machine over AirPlay and the list is close to empty, because the audio has already left the Core Audio graph by the time AirPlay touches it.
SoundFerry sidesteps that by being the output device. Everything the Mac plays is captured at the top of the chain, processed in double precision, and only then handed to AirPlay. Every speaker in the group receives the tuned signal.
Which matters most when the speakers are honest ones. A WiiM Amp into bookshelf speakers in an untreated room is exactly what a parametric EQ was invented for.
The whole chain
Input gain → EQ → dynamics → width → delay → reverb → output gain → limiter → metering → dither → 16-bit → AirPlay.
Stage 1
Parametric EQ — 12 bands
Peaking, low/high shelf, low/high cut, notch and band-pass. Each band assignable to L/R, mid or side. RBJ cookbook designs in double-precision transposed direct form II — the curve you see is drawn from the same equations the audio goes through.
Stage 2
Dynamics — 1 or 3 band
Fourth-order Linkwitz-Riley crossovers with a matching all-pass on the low band, so a flat setting really is flat. Soft-knee gain computation in dB, program-dependent release, stereo link continuously variable 0–100%.
Stage 3
Stereo width + bass mono
Mid/side width control with a mono-below frequency. Sending correlated bass to speakers in different rooms is how you get cancellation through wall reflections; this is the fix.
Stage 4
Delay and reverb
Independent left/right time, ping-pong, and low/high cut inside the loop so repeats narrow instead of muddying. Reverb is an 8-line FDN with a Hadamard feedback matrix, pre-delay, 10-tap early reflections and modulated read positions — the RT60 you dial is the RT60 you measure.
Stage 5
Look-ahead limiter
Limits peaks before audio is sent to the selected output group. Test levels and timing on your setup.
Stage 6
Dither + metering
AirPlay's pipe is 16-bit and that conversion is the only lossy step in the chain. TPDF dither decorrelates the quantisation error and second-order noise shaping (NTF
(1 − z⁻¹)²) moves it up — about 10 dB less noise below 6 kHz, measured. Loudness and true peak per ITU-R BS.1770-4.
Presets, for when you do not want to think
| Group | Presets |
|---|---|
| Venue | Club · Live house · Outdoor festival · Concert hall · Jazz club · Arena · Cathedral |
| Correction | Reference · Audiophile · Vocal clarity · Warm vintage |
| Scene | Late night · Background music · Podcast & spoken word |
Default is Reference — every effect bypassed, dither only. Nothing is done to your audio unless you ask for it.
Questions about the sound
Does macOS have a system-wide equalizer?
No. The Music app has one and it applies only to Music. There is nothing that touches Spotify, a browser tab or VLC, and nothing at all that shapes what goes out over AirPlay.
What does the equalizer actually do?
Group-wide EQ, dynamics and reverb process the shared audio before it reaches the speakers. The same processing applies to every selected output.
Can I set a different EQ per speaker?
SoundFerry applies EQ to the group as a whole. It provides per-speaker delay adjustment, but does not provide a separate EQ for each speaker.
Does the EQ add latency?
EQ and dynamics process audio before streaming. The delay before a change is audible depends on buffering, settings and the receiver.
How much CPU does the whole chain cost?
CPU use varies with your Mac, enabled effects and output configuration. We have not published a representative release benchmark. Check playback on your own setup.
Can I hear my changes immediately?
EQ and dynamics process audio before streaming. The delay before a change is audible depends on buffering, settings and the receiver.
Is this a loudness enhancer?
No, and it is worth being blunt about it. Reverb on an already-reverberant recording, in a room with its own reflections, sounds worse. The venue presets are an effect, not an improvement. The correction presets and the EQ are the parts that make a real speaker in a real room sound right.
If you use a boosting preset, leave the limiter on — 16-bit conversion hard-clips at ±1.
How much is it, and is it a subscription?
19 USD buys a perpetual license for version 1.x. Updates such as 1.0 to 1.1 are included. Version 2.x requires a separate purchase, with pricing not yet decided. There is no subscription. Other currencies are converted from the USD price.
Tune it for your room, not for a spec sheet.
Every band, every preset, 7 days free. $19 once if you keep it.
- One-time purchase, no subscription
- Free updates within 1.x
- macOS 14+, Apple silicon