Control

Space (Reverb Decay)

Space sets reverb decay from 1.2 to 6.0 s, default 2.4 s. Learn how the tail is built, how its treble fades, how decay fits tempo, and lengths for each style.

Open the free editor: upload MP3, WAV, AAC, OGG or FLAC, adjust speed, reverb, bass, tone, width and space, then export MP3 or a ZIP of many tracks. Everything runs in your browser.

Space is the size of the room. It sets how long the reverb tail lasts, from 1.2 to 6.0 seconds, with a default of 2.4 s. It is the control that turns the same reverb mix into a tiled bathroom at one end or a cathedral at the other. The Haze Chamber preset sits at the short end on purpose. Most people who add reverb to a song for the first time reach for the mix slider when they want "more room" and end up with a wet mess. The room is this slider. This page covers how the tail is built, what the decay number means in practice, how it fits against the tempo of a slowed track, and which lengths suit which material.

What Space does in signal terms

The editor's reverb is a convolution reverb. It needs an impulse response, a short recording of how a space answers a single click, and it runs the song through that response. The editor does not ship with sampled rooms. It synthesises the impulse response in your browser every time you change Space, and the Space value is the length of the tail it generates.

How the tail is built:

• Pre-delay of 10 ms. The first 10 ms are silent. This tiny gap separates the direct sound from the first reflection and keeps the dry signal distinct from the tail.
• Early reflections. Five discrete echoes land at 11, 19, 31, 43 and 57 ms after the pre-delay, each quieter than the last. The right channel's reflections are offset by 1.5 ms so the two channels are not identical. These echoes are what give the ear a sense of walls at a particular distance.
• A noise-based tail. The late reverb is filtered noise with an envelope that falls from full level to silence over the Space duration. The curve is steeper than linear, so the tail loses most of its energy in the first half and fades gently at the end.
• High-frequency damping over the tail. A low-pass filter on the noise starts with its cutoff at 9000 Hz and sweeps down to 1200 Hz by the end of the tail. Early reflections are bright; late reflections are dark. That mirrors real rooms, where air and soft surfaces absorb treble faster than bass, and it is why the tail sounds warm rather than hissy.
• Normalisation. The whole response is scaled so its peak is consistent regardless of length. Changing Space changes the character of the tail, not the overall loudness of the reverb path.

One detail worth knowing: the envelope reaches silence at the Space value. Studio reverbs usually quote RT60, the time for the tail to fall by 60 dB, and a 2.4 s RT60 would still have a faint tail beyond 2.4 s. Here, 2.4 s means the tail is finished at 2.4 s. The numbers feel a little shorter than the equivalent RT60 on a hardware unit.

How damping changes with length

Because the cutoff sweeps across the whole tail, the Space value also controls how fast the reverb darkens. At 1.2 s the cutoff travels from 9 kHz to 1.2 kHz in just over a second, so the tail goes dark almost immediately. That is why the Haze Chamber preset sounds smoky even with a 54% mix. At 6.0 s the same sweep takes five times longer, so the first couple of seconds of the tail stay open and airy before settling. Long settings sound brighter in the early tail even though both end at the same 1.2 kHz.

Decay and tempo

The decay is measured in seconds of the output, after the speed change. Slowing a song does not stretch the tail, but it does move the beats apart. That changes how many beats a given decay covers:

A useful rule: a decay roughly equal to one bar sounds musical, because the tail from a downbeat has faded by the next downbeat. Shorter than a beat and the room feels small. Longer than two bars and phrases start to overlap, which is fine for ambient material and tiring for songs. The speed control page has the full BPM table if you want to work out your own bar lengths.

Decay versus feel

Read the third column with the first. As the decay grows, the mix that still sounds clear shrinks. That is the core trade: long rooms need to be quieter rooms.

How Space interacts with the other controls

Reverb. Covered above, but the short version is that these two are set together. Decide the size of the room, then decide how far from the source you are standing.

Speed. Slower playback spreads the beats, so a tail that was crowding a 120 BPM track breathes at 0.85x. If you set a decay at 1.00x and then slow the song, the tail will feel shorter relative to the beat. Set Speed first.

Tone. Tone sits before the reverb split, so a dark Tone feeds darker material into an already-darkening tail. At long decays with a very negative Tone the late reverb can turn to low-mid rumble. If a long Space sounds thick, raise Tone a little before shortening the decay.

Bass. Also before the split. A heavy bass boost puts a lot of low energy into the convolver, and low frequencies have the least damping in the tail. At 4 s and above with +10 dB bass, expect a boom under everything. Pull Bass to +6 or shorten Space.

Width. A longer stereo tail is more noticeable when widened. At 4 s and 1.4 width the room feels enormous on headphones.

Setting Space by ear

1. Pick Speed. Leave it.
2. Set Reverb to about 35% so the tail is clearly audible but not dominant.
3. Start Space at 1.2 s and listen to the snare or a vocal phrase ending. The tail should stop short.
4. Move to 2.4 s. The tail should now cover roughly a bar.
5. Move to 4.0 s. Phrases should start to overlap.
6. Choose the length where the end of one phrase just touches the start of the next. For dense songs that is shorter; for sparse songs longer.
7. Now fine-tune Reverb. You will often find you can raise it slightly at shorter decays and must lower it at longer ones.

Mistakes with Space

• Using Space to fix a wet mix. If vocals are buried, shortening the decay helps a little but lowering Reverb fixes it. Start with the mix.
• Maxing it because "epic". 6.0 s on a song with lyrics turns the chorus into a single chord. Save it for intros and ambient beds.
• Setting it before Speed. The relationship between tail and beat changes with every speed move.
• Ignoring the low end. Long decays plus heavy bass is the most common cause of low-mid rumble in slowed edits. Trim one or the other.
• Forgetting that Lift stores a decay too. Every preset keeps a Space value even at 0% Reverb. The Lift preset carries 2.2 s so the moment you add a little reverb to a sped up edit the tail is already a sensible length.

Space and the export

Export is MP3 at 96 kbps and 32 kHz, encoded in a web worker in your browser. Because the tail darkens toward 1.2 kHz and the encoder's 32 kHz sample rate caps content at 16 kHz, almost nothing in a long reverb tail is lost to the format. The export is fine for YouTube, TikTok and Shorts since they re-encode uploads. For a distribution master, use a WAV source in a DAW; the editor does not export WAV.