Sound design
How to EQ Spotify before it reaches AirPlay
There is exactly one place in the chain where this can happen, and it is not in Spotify and not in the speaker. This page is about that place, and about the two settings worth changing before any EQ band.
Where processing can and cannot happen
Audio from Spotify to a HomePod passes through four hands. Only one of them is yours.
- 01
Spotify decodes the track
No equalizer on macOS or Windows — Spotify's EQ is a mobile-only feature. Nothing to configure here.
- 02
The macOS output device receives it
This is the only point you control. Whatever device is selected gets the audio as plain PCM and can do anything it likes with it before passing it on.
- 03
AirPlay encodes and ships it
Encoded to ALAC, timestamped against the group clock, sent. Past this point no Mac application can intervene.
- 04
The speaker does whatever it does
A HomePod applies its own correction. A Sonos applies Trueplay. A WiiM applies its device EQ. You get whatever settings that vendor exposes, and no more.
Six steps that matter, in this order
- 01
Set the Mac's output to SoundFerry
Spotify plays into it like any other output device. It needs no plug-in, no extension and no setting changed inside Spotify.
- 02
Open the Sound tab
It starts on Reference — everything bypassed, dither only. Nothing is done to your audio until you ask.
- 03
Turn on bass mono-ing first
Before touching a single band. Correlated low frequencies arriving in one room from two speakers cancel; mono-ing below about 120 Hz gets the bass back.
- 04
Cut before you boost
Find what is wrong and take it out. A 3 dB cut at 250 Hz fixes more rooms than any amount of boosting, and it leaves headroom instead of eating it.
- 05
Leave the limiter on
The 16-bit conversion at the end of the chain hard-clips at ±1. Latency is identical whether the limiter is engaged or not, so there is no reason to switch it off.
- 06
Wait two seconds before judging
AirPlay buffers about several seconds depending on settings and devices. Move a slider, count to three, then listen. Fighting the delay is how people end up over-correcting.
What is actually in the chain
12 parametric bands — peaking, low and high shelf, low and high cut, notch, band-pass — each assignable to left/right, mid or side, implemented from the RBJ cookbook in double-precision transposed direct form II. The curve on screen is drawn from the same equations the audio goes through, so it is a measurement rather than a decoration.
EQ and dynamics process audio before streaming. The delay before a change is audible depends on buffering, settings and the receiver.
CPU use varies with the preset, Mac and output configuration. Full technical detail →
Questions
Does the Spotify desktop app have an equalizer?
No. Spotify's equalizer exists on iOS and Android only. On macOS and Windows there is no EQ in the app at all, and there is no setting hidden anywhere that turns one on.
Why does the EQ have to happen before AirPlay?
Because once audio has been handed to AirPlay it is encoded, timestamped and gone. There is no point after that where a Mac application can intervene — the next thing that touches it is the speaker.
So the only place to shape it is upstream, on the Mac, while it is still an audio stream. SoundFerry sits exactly there: it is the output device Spotify plays into, and it processes before handing off.
Can I use eqMac, SoundSource or Boom for this?
Not for AirPlay. Those shape audio on its way to your built-in speakers or headphones, which is a different output device and a genuinely useful thing — but they are not what is sending a synchronised stream to four AirPlay speakers, and only one output device can be selected at a time.
Owning both is normal. See which Mac EQ covers what.
What about Spotify Premium or a higher streaming quality?
Neither changes anything here. SoundFerry takes the audio after Spotify has decoded it, so your plan and quality setting are upstream of everything on this page. Setting Spotify to its highest quality is still worth doing — it is just a separate matter.
Will this help a bass-shy HomePod mini?
Less than you would hope. A HomePod applies its own opaque correction and dynamic processing after receiving audio, so boosting the bass in the stream partly gets undone. It works much better on speakers that pass the signal through honestly — a WiiM into a real amplifier, an AirPlay 2 Sonos, an Apple TV feeding a receiver.
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.
How much delay is there?
The managed default audio path adds several seconds of delay. It is intended for listening rather than live instrument monitoring, gaming or video calls. Video playback may need delay compensation.
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.
What is in the free trial?
The trial lasts seven days and requires no payment card. An internet connection is required to start it, after restarting the app, and every 12 hours during use. The server manages expiry; changing the Mac clock does not extend it. Purchased licenses are verified offline.
Shape it once, hear it everywhere.
Every band, every preset, free for 7 days. $19 once.
- One-time purchase, no subscription
- Free updates within 1.x
- macOS 14+, Apple silicon