Delay Effects

Effects built with delay lines.

class tiliqua.dsp.delay_effect.PingPongDelay(*args, src_loc_at=0, **kwargs)

2-channel stereo ping-pong delay.

Based on 2 equal-length delay lines, fed back into each other.

Delay lines are created external to this component, and may be SRAM-backed or PSRAM-backed depending on the application.

Members:

• i (In(stream.Signature(data.ArrayLayout(ASQ, 2)))) – Stereo sample pairs into ping-pong delay.

• o (Out(stream.Signature(data.ArrayLayout(ASQ, 2)))) – Stereo sample pairs out of ping-pong delay. One per input.

__init__(delayln1, delayln2, delay_samples=15000)

delayln1delay_line.DelayLine

First delay line, must have max length > delay_samples, and have been created with DelayLine.write_triggers_read == True.

delayln2delay_line.DelayLine

Second delay line, must have max length > delay_samples, and have been created with DelayLine.write_triggers_read == True.

delay_samplesint

Length of each ping-pong section in samples.

class tiliqua.dsp.delay_effect.Diffuser(*args, src_loc_at=0, **kwargs)

4-channel shuffling feedback delay.

Based on 4 separate delay lines with separate delay lengths, where the feedback paths are shuffled into different channels by a matrix mixer.

Delay lines are created external to this component, and may be SRAM-backed or PSRAM-backed depending on the application.

Members:

• i (In(stream.Signature(data.ArrayLayout(ASQ, 4)))) – Sample array into the delay effect.

• o (Out(stream.Signature(data.ArrayLayout(ASQ, 4)))) – Sample array out of the delay effect. One is produced per input.

__init__(delay_lines, delays=None)

delay_lines[delay_line.DelayLine]

Array of 4 delay lines used for feedback. Each delay line must be at least as long as the corresponding entry in delays.

delays[int]

Fixed tap delay of each feedback path - one for each delay line. If not provided, some default tap lengths are used.

class tiliqua.dsp.delay_effect.Boxcar(*args, src_loc_at=0, **kwargs)

Simple Boxcar Average.

Average of previous N samples, implemented with an accumulator and delay line. The accumulator sums all incoming samples, and we subtract an N-sample-delayed version of the incoming signal. This is the same as taking the average over the last N samples, requiring no multiplies but instead requiring space for N samples.

Can be used in low- or high-pass mode.

Members:

• i (In(stream.Signature(sq))) – Samples into the boxcar averager.

• o (Out(stream.Signature(sq))) – Samples out of the boxcar averager, one produced per input.

__init__(n=32, hpf=False, sq=ASQ)

nint

Delay line size and window length of the averager.

hpfbool

High-pass mode - if true, the average value is subtracted from the last sample and we emit the difference, rather than emitting the average value itself. Almost no extra cost, useful for other applications.

sqfixed.SQ

Fixed-point type used for underlying inputs, outputs and storage.