Why does the output have a tail added?

Because a reverb continues after the source stops. The comb loops keep recirculating until the feedback is damped away, so the output is the source length plus two seconds to hold that decay. Cutting it at the end of the source would clip the tail off mid-decay.

What does damping actually change?

How much high frequency is lost on each pass through the comb loops. With heavy damping the tail goes dark quickly, which reads as a large distant hall; with light damping it stays bright, which is the plate character. It is the control that decides the colour of the tail rather than its length.

Why is the reported decay only an estimate?

Because it is computed from the size and feedback settings rather than measured from the rendered audio. It is close enough to choose settings by, and it is honest about being an approximation, but a real time to fall sixty decibels would have to be measured from the output.

Is mix at zero really dry?

Yes, exactly. At zero the dry signal passes through untouched, which is a useful reference point: set the control to zero, apply, and compare against the file you started with to confirm nothing else has changed.

How much reverb should I use on a vocal?

Under forty percent is the usual advice, which leaves the words in front of the space rather than inside it. If the voice starts to sound distant, the mix is too high; if the tail is audible as a separate sound, the decay or the size is too long.

Reverb Simulator

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Reverb Simulator puts a room around a recording using the classic algorithmic topology rather than a recording of a real space. Four damped combs and two allpasses build a tail whose length and colour you set.

What is Reverb Simulator?

Choose a file, set the four controls, and apply; the result is a WAV as long as the source plus the tail.

The controls:

A room size from half to double, defaulting to one, which scales the comb delays and therefore the spacing of the early reflections.
A sustain figure from sixty to ninety percent, defaulting to seventy five, which is the feedback in the comb loops.
A damping frequency from one to eight kilohertz, defaulting to four, in steps of two hundred and fifty hertz.
A mix from nothing to everything, defaulting to thirty percent, with nothing meaning an exact dry passthrough.

The topology is the one Manfred Schroeder described in 1961: four parallel comb filters, each with its own delay and a damped feedback path, then two allpass filters in series to smear the result into something that does not sound like a set of discrete echoes. That combination is what still defines what people mean by an algorithmic plate. The parallel damped combs are where the tail comes from: each one recirculates its own delayed copy of the signal, and the feedback determines how long it takes to decay, so the sustain control is really a decay length control. Damping is applied inside each comb's loop, so each pass through the filter discards a little high frequency, which is why a real tail gets darker as it fades and why damping is what makes the difference between a bright plate and a distant hall. The size control changes the comb delays themselves, which moves the spacing of the early reflections and so changes the perceived dimensions of the room rather than merely its decay. The reported decay figure is deliberately described as a rough estimate, because it is computed from the size and feedback settings rather than measured from the rendered tail, and the output is exactly the source length plus two seconds, allowing for the tail to run past the end of the material. What the tool is not is a sampler of real rooms: it has no early-reflection pattern from an actual space, so it will not convince anyone that a voice was recorded in a cathedral, but it will put a smooth, tunable space behind anything.

What it does not do:

No convolution with a real impulse response, so it cannot reproduce a specific space.
No pre-delay control.
The decay figure shown is an estimate from the settings rather than a measurement.
No separate control of early reflections and tail.
No modulation of the tail, so long decays can sound slightly static.
Output is sixteen bit WAV with two seconds of tail appended.

Use it for the ordinary job of putting a little space behind a dry recording: a vocal that needs to sit back, a drum bus that wants glue, or a synth that needs to sound less like it was made on a laptop. When the aim is to match a specific room rather than to invent one, the convolution reverb uses a measured impulse instead, and when the question is which decay length will not fight the tempo, the reverb time calculator answers that before any processing happens.

How to use Reverb Simulator

Drop an audio file onto the panel and wait for it to decode.
Set the room size and sustain for the decay length you want.
Set the damping for how bright the tail should be, and the mix for how much of it to hear.
Apply the reverb and download the WAV, which includes two seconds of tail.

When to use Reverb Simulator vs related tools

Reverb Simulator is the tool for adding an invented space behind dry material with full control of its decay and colour. Convolution Reverb uses a measured impulse response instead, which is the right choice when a specific space has to be matched. Hallway Room Simulator is the quicker one-purpose option, and Reverb Time Calculator works out the decay figures that will not smear across the beat.

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