Method, device and application for implementing audio delay effect based on impulse response sequence

Abstract

The application provides a method, device and application for realizing an audio delay effect based on a pulse response sequence, comprising: inputting a pulse response of desired delay effect audio data; preprocessing the pulse response of the desired delay effect, extracting N discrete pulse responses and a starting delay time corresponding to each discrete pulse response, and determining a main period of the pulse response sequence; respectively convolving an input audio signal with each discrete pulse response to generate a convolution signal corresponding to each discrete pulse response; calculating an actual delay amount corresponding to each discrete pulse response based on the starting delay time corresponding to each discrete pulse response, the main period of the pulse response sequence and a set adjustable target delay time; delaying the convolution signal corresponding to each discrete pulse response by the actual delay amount corresponding to each discrete pulse response to output N signals; mixing the output N signals to generate a final delay effect output signal, and acquiring a high-quality delay effect in real time.

Description

Technical Field

[0001] This invention belongs to the field of audio signal processing technology, and in particular to a method, apparatus and application for achieving audio delay effect based on impulse response sequence. Background Technology

[0002] Delay effects are among the most basic and important effects in audio processing, widely used in music production, film sound design, live sound reinforcement, and post-recording processing to create echo, spatiality, rhythm, and various special sound effects. Delay effects units (generally called delay effects or echo effects) are one of the most common audio processing units in music production, recording, and live performances. Existing delay processing methods are mainly divided into the following categories:

[0003] Simple digital delay: By delaying the input signal for a specific time before outputting it, and feeding back part of the output signal to the input, an echo effect is created. Its structure is simple, and the delay time and feedback amount are easy to control precisely. However, the echo pattern it produces is highly regular and monotonous, and the timbre is monotonous and lacks variation. It is difficult to simulate the complex and irregular reflection characteristics in a real physical environment, and its timbre shaping ability is limited.

[0004] Analog delay (such as tape delay, BBD delay): This type of delay is implemented through physical devices and has unique spectral characteristics and nonlinear distortion. However, analog delay devices have high maintenance costs, limited delay time ranges, and their unique tonal characteristics are difficult to accurately replicate using traditional digital delay algorithms.

[0005] Digital delay: This type of delay relies on digital signal processing algorithms and has precise time control capabilities, but lacks natural decay and complex timbre characteristics.

[0006] Convolutional reverb / delay: By convolving sound with impulse response (IR), spatial acoustic characteristics can be reproduced. However, it is often used for reverb. If it is directly applied to delay, the computational complexity is high, and the core delay parameters cannot be adjusted in real time. Once the impulse response is determined, the delay time, echo sequence and attenuation characteristics it represents are fixed. Users cannot flexibly adjust the core parameters (such as delay time and feedback amount) during real-time processing, which greatly limits its application in music creation and performance that require real-time interaction.

[0007] In summary, existing delay technologies have the following shortcomings:

[0008] Limited tonal shaping capabilities: All delay effects, except for convolution, rely on combinations of delay, filters, and feedback. The tonal possibilities are limited, and the combinations are fixed and periodic in time. Higher degrees of freedom in tonal design are not possible. For example, you cannot use the complex tone and timing of a ping-pong ball dropped on the ground as a delay effect.

[0009] Insufficient versatility: Different latency types require different algorithms or hardware support, making it impossible to replicate these diverse acoustic characteristics with a unified framework.

[0010] Limited real-time operability: Although traditional convolution methods can solve the problems of timbre realism and complexity, their inherent static processing characteristics make it impossible for users to dynamically adjust key parameters such as delay time and feedback in real-time applications, just like operating traditional delay effects, resulting in a serious lack of flexibility. Summary of the Invention

[0011] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method, apparatus, and application for achieving audio delay effects based on impulse response sequences.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] On one hand, the present invention provides a method for achieving audio delay effects based on impulse response sequences, comprising the following steps:

[0014] The impulse response of the input audio data with the desired delay effect;

[0015] The impulse response with the desired delay effect is preprocessed to extract N discrete impulse responses and the starting delay time corresponding to each discrete impulse response, and the main period of the impulse response sequence is determined.

[0016] Input the audio signal to be processed;

[0017] The input audio signal is convolved with each discrete impulse response to generate a convolution signal corresponding to each discrete impulse response.

[0018] Based on the initial delay time corresponding to each discrete impulse response, the main period of the impulse response sequence, and the set adjustable target delay time, calculate the actual delay amount corresponding to each discrete impulse response;

[0019] Delay the convolutional signal corresponding to each discrete impulse response by the actual delay amount, and output N signals;

[0020] The N output signals are mixed to generate the final delayed output signal.

[0021] On the other hand, the present invention provides an apparatus for achieving an audio delay effect based on an impulse response sequence, comprising:

[0022] The first module is used to input the impulse response of the audio data with the desired delay effect;

[0023] The second module is used to preprocess the impulse response with the desired delay effect, extract N discrete impulse responses and the starting delay time corresponding to each discrete impulse response, and determine the main period of the impulse response sequence.

[0024] The third module is used to input the audio signal to be processed;

[0025] The fourth module is used to convolve the input audio signal with each discrete impulse response to generate a convolution signal corresponding to each discrete impulse response.

[0026] The fifth module is used to calculate the actual delay amount corresponding to each discrete impulse response based on the starting delay time, the main period of the impulse response sequence, and the set adjustable target delay time.

[0027] The sixth module is used to delay the convolution signal corresponding to each discrete impulse response by the actual delay amount, and output N signals.

[0028] The seventh module is used to mix the N output signals to generate the final delayed output signal.

[0029] The above-mentioned method for achieving audio delay effects based on impulse response sequences is applied to guitar effects by pre-loading the method for achieving audio delay effects based on impulse response sequences into the DSP processing unit of the guitar effects unit.

[0030] On the other hand, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described method for achieving audio delay effect based on impulse response sequence.

[0031] On the other hand, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method for achieving audio delay effects based on impulse response sequences.

[0032] On the other hand, the present invention provides a computer program product stored on a computer-readable storage medium and including computer instructions that, when executed by a processor, cause a computer device to implement the steps of the method for achieving an audio delay effect based on an impulse response sequence described above.

[0033] Compared with the prior art, the technical effects of the present invention are as follows:

[0034] Traditional digital delays typically produce only regular, monotonous echoes. However, in this invention, the impulse response of the audio data used to input the desired delay effect can come from any real-world environment. For example, using the audio of a ball bouncing on stairs as the impulse response, the sound processed by this invention will produce a complex pattern resembling the ball bouncing on stairs. The impulse response can be a drumbeat, a vocal track, or any other sound. This invention can create delay effects based on any audio, achieving high-quality, real-time adjustable delay times that simulate complex spatial acoustics, while significantly reducing computational complexity and implementation difficulty.

[0035] Specifically, directly using a complete, long impulse response convolved with audio, changing the delay time would severely alter its spectral characteristics, leading to pitch changes and unnatural effects. Therefore, this invention proposes preprocessing the impulse response for the desired delay effect, extracting N discrete impulse responses and their corresponding initial delay times. This results in high timbre freedom; short IRs, acting as "timbre units," can be flexibly superimposed and combined to form arbitrary spectral characteristics, creating various effects previously nonexistent.

[0036] Furthermore, the input audio signal is convolved with each discrete impulse response separately to generate a convolutional signal corresponding to each discrete impulse response. Based on the initial delay time of each discrete impulse response, the main period of the impulse response sequence, and the set adjustable target delay time, the actual delay amount corresponding to each discrete impulse response is calculated. The convolutional signal corresponding to each discrete impulse response is then delayed by the actual delay amount, and N signals are output. The N output signals are then mixed to generate the final delay effect output signal. By discretizing the impulse response, high-quality convolutional delay effects can be obtained in real time. Convolving the input audio signal with each discrete impulse response separately requires far less computation than convolving with long impulse responses, significantly reducing the computational cost of convolution and making it suitable for real-time operation. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0038] Figure 1 This is a flowchart of a method for achieving audio delay effect based on impulse response sequence in one embodiment;

[0039] Figure 2This is a typical schematic diagram of a complete impulse response;

[0040] Figure 3 To Figure 2 The diagram shows the discrete impulse response extracted after preprocessing, and the starting delay time corresponding to each discrete impulse response. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] Reference Figure 1 One embodiment proposes a method for achieving audio delay effects based on impulse response sequences, comprising the following steps:

[0043] The impulse response of the input audio data with the desired delay effect;

[0044] The impulse response with the desired delay effect is preprocessed to extract N discrete impulse responses and the starting delay time corresponding to each discrete impulse response, and the main period of the impulse response sequence is determined.

[0045] Input the audio signal to be processed;

[0046] The input audio signal is convolved with each discrete impulse response to generate a convolution signal corresponding to each discrete impulse response.

[0047] Based on the initial delay time corresponding to each discrete impulse response, the main period of the impulse response sequence, and the set adjustable target delay time, calculate the actual delay amount corresponding to each discrete impulse response;

[0048] Delay the convolutional signal corresponding to each discrete impulse response by the actual delay amount, and output N signals;

[0049] The N output signals are mixed to generate the final delayed output signal.

[0050] The essence of a delay effect is a discrete impulse response. It consists of multiple short impulse responses distributed over time. The method for obtaining the impulse response sequence of the desired delay effect audio data is not limited; it can be obtained using standard impulse response testing methods, such as using a swept sine wave output through a delay effect and then deconvolution, or it can directly use some audio as the impulse response, such as a drum kit or the sound of a ball bouncing. An ideal delay effect should delay the sound multiple times, and the delay time should be adjustable in real time. Convolving a complete impulse response makes it difficult to stretch the convolution kernel in real time. Therefore, this invention preprocesses the impulse response of the desired delay effect, extracting N discrete impulse responses and the corresponding initial delay time for each discrete impulse response. This way, by simply adjusting the delay time of each discrete impulse response in real time, it can become a standard delay effect.

[0051] In one specific embodiment, extracting N discrete impulse responses and the corresponding start delay time for each discrete impulse response includes the following steps:

[0052] Set the sampling rate, analysis window length, and the number of discrete impulse responses N to be extracted;

[0053] The impulse response sequence is divided into a series of samples based on the sampling rate;

[0054] Starting with each sample of the impulse response sequence, a signal segment of one analysis window length is selected, and the energy value of the signal segment within each analysis window is calculated to obtain the initial energy value sequence.

[0055] Based on the initial energy value sequence, N discrete peak windows are found. The signal segment corresponding to the N discrete peak windows is a discrete impulse response. The time interval between the starting sample position of the peak window and the starting point of the impulse response sequence is used as the starting delay time of the discrete impulse response.

[0056] Reference Figure 2 , Figure 2 This is a typical schematic diagram of a complete impulse response, which can be seen to be composed of several sparse short impulse responses. Figure 3 To Figure 2 The diagram shows the discrete impulse response extracted after preprocessing, along with the start delay time corresponding to each discrete impulse response. The preprocessing steps provided in the above embodiment are used to... Figure 2 The impulse response shown is decomposed into several short impulse responses, and the initial delay time corresponding to each discrete impulse response, as well as the main delay time analyzed from them.

[0057] In one specific embodiment, the energy value of the signal segment within each analysis window is calculated using the following formula:

[0058]

[0059] in Therefore m The first analysis window with the starting point m + i Each audio sample value, i The value range is 0 to L , L The preset analysis window length, Representative with m The energy value of the signal terminal within the analysis window, starting from the point.

[0060] In one specific embodiment, based on the initial energy value sequence, N discrete peak windows are found. The signal segment corresponding to the N discrete peak windows is a discrete impulse response. The time interval between the starting sample position of the peak window and the starting point of the impulse response sequence is used as the starting delay time corresponding to the discrete impulse response. The process includes the following steps:

[0061] (i) Input the initial energy value sequence;

[0062] (ii) Find the analysis window with the largest energy value in the current energy value sequence and use it as the peak window found in this time;

[0063] (iii) Record the time interval between the starting sample position of the peak window and the starting point of the impulse response sequence as the starting delay time corresponding to the discrete impulse response, and extract audio data from the impulse response sequence starting from the starting sample position of the peak window with a length equal to the length of the analysis window as an extracted discrete impulse response;

[0064] (iv) In the current energy value sequence, with the peak window found this time as the center, set the energy values ​​within the length range of at least one analysis window before and after the peak window to zero or mark them as invalid. This can prevent the side lobes of the same peak from being found multiple times. A new energy value sequence is obtained, the current energy value sequence is updated, and the process returns to step (ii) until N discrete impulse responses and the start delay time corresponding to each discrete impulse response are obtained.

[0065] Next, the master period is located. Delay effects typically have a master period, such as 0.5s, meaning the effect repeats in 0.5-second intervals. This master period can be adjusted during use, manifested as adjusting the delay of the impulse response. Therefore, the master period needs to be analyzed from the impulse response sequence for display and adjustment by the user. In a specific embodiment, determining the master period of the impulse response sequence includes:

[0066] For each discrete impulse response, find the location of the maximum absolute value of amplitude within the audio data corresponding to the discrete impulse response, and take the time interval between the location of the maximum absolute value of amplitude and the start of the impulse response sequence as the peak delay time of the discrete impulse response.

[0067] Calculate the difference between each pair of peak delay times for all discrete impulse responses;

[0068] The peak value of the difference is statistically analyzed, and the peak value is used as the main period of the impulse response sequence.

[0069] In one specific embodiment, based on the start delay time corresponding to each discrete impulse response, the main period of the impulse response sequence, and the set adjustable target delay time, the actual delay amount corresponding to each discrete impulse response is calculated as delay(n)*d / D, where delay(n) represents the start delay time corresponding to the nth discrete impulse response, D represents the main period of the impulse response sequence, and d represents the set adjustable target delay time.

[0070] In another embodiment, an apparatus for achieving an audio delay effect based on an impulse response sequence is provided, comprising:

[0071] The first module is used to input the impulse response of the audio data with the desired delay effect;

[0072] The second module is used to preprocess the impulse response with the desired delay effect, extract N discrete impulse responses and the starting delay time corresponding to each discrete impulse response, and determine the main period of the impulse response sequence.

[0073] The third module is used to input the audio signal to be processed;

[0074] The fourth module is used to convolve the input audio signal with each discrete impulse response to generate a convolution signal corresponding to each discrete impulse response.

[0075] The fifth module is used to calculate the actual delay amount corresponding to each discrete impulse response based on the starting delay time, the main period of the impulse response sequence, and the set adjustable target delay time.

[0076] The sixth module is used to delay the convolution signal corresponding to each discrete impulse response by the actual delay amount, and output N signals.

[0077] The seventh module is used to mix the N output signals to generate the final delayed output signal.

[0078] The above-mentioned method for achieving audio delay effects based on impulse response sequences is applied to guitar effects by pre-loading the method for achieving audio delay effects based on impulse response sequences into the DSP processing unit of the guitar effects unit.

[0079] In one embodiment, the device for achieving audio delay effects based on impulse response sequences provided in the above embodiments is embedded in a guitar effects processor, and its hardware platform includes:

[0080] Input module: High-impedance guitar input interface with preamplifier and A / D conversion circuit;

[0081] DSP processing unit: Employs digital signal processing chips (such as SHARC DSP, ARM Cortex-M series) or FPGAs to run a method based on impulse response sequences to achieve audio delay effects;

[0082] Control module: knobs, foot switches, LCD screen, etc., used to adjust parameters such as delay time, feedback quantity, IR selection, and mixing ratio;

[0083] Output module: D / A conversion and low-impedance drive circuit, used for output to speakers or audio interfaces.

[0084] Playing a sweep signal from the guitar effects pedal's output, and connecting other devices, then connecting the other devices' outputs to the guitar effects pedal's input, recording feedback signals, and performing impulse response analysis, yields a clone of the other delay devices. This effect can then be used in real-time for performance and control. Real-time response: Due to the efficiency of short IR convolution, the entire system's processing latency is less than 5ms, ensuring immediate feedback for stage performances.

[0085] On the other hand, the present invention provides a computer device including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the method for achieving audio delay effects based on impulse response sequences provided in any of the above embodiments. The computer device may be a server. The computer device includes a processor, a memory, a network interface, and a database connected via a system bus. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device stores sample data. The network interface of the computer device is used for communication with external terminals via a network connection.

[0086] On the other hand, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, it implements the steps of the method for achieving audio delay effect based on impulse response sequence provided in any of the above embodiments.

[0087] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0088] Matters not covered in this invention are common knowledge.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of implementing an audio delay effect based on a sequence of impulse responses, characterized by, The method comprises the following steps: inputting a pulse response of desired delay effect audio data; preprocessing the pulse response of desired delay effect, extracting N discrete pulse responses and a starting delay time corresponding to each discrete pulse response, and determining a main period of the pulse response sequence, wherein determining the main period of the pulse response sequence comprises: for each discrete pulse response, finding a position of an amplitude absolute maximum value in audio data corresponding to the discrete pulse response, taking a time interval of the position of the amplitude absolute maximum value relative to a starting point of the pulse response sequence as a peak delay time of the discrete pulse response; calculating a difference between the peak delay times of all discrete pulse responses; and counting a peak value of the difference, taking the peak value as the main period of the pulse response sequence; inputting an audio signal to be processed; convolving the input audio signal with each discrete pulse response respectively to generate a convolution signal corresponding to each discrete pulse response; Based on the starting delay time corresponding to each discrete pulse response, the main period of the pulse response sequence and the set adjustable target delay time, the actual delay amount corresponding to each discrete pulse response is calculated as wherein denotes the starting delay time corresponding to the nthdiscrete pulse response, D denotes the main period of the pulse response sequence, and d denotes the set adjustable target delay time. delaying the convolution signal corresponding to each discrete pulse response by a corresponding actual delay amount to output N signals; mixing the output N signals to generate a final delay effect output signal.

2. The method for implementing an audio delay effect based on a sequence of impulse responses according to claim 1, wherein, The extracting of N discrete pulse responses and a starting delay time corresponding to each discrete pulse response comprises the following steps: setting a sampling rate, an analysis window length, and a number N of discrete pulse responses to be extracted; dividing the pulse response sequence into a series of samples according to the sampling rate; taking a signal segment of the analysis window length as a starting point of each sample of the pulse response sequence, calculating an energy value of the signal segment in each analysis window to obtain an initial energy value sequence; based on the initial energy value sequence, finding N discrete peak windows, the signal segment corresponding to the N discrete peak windows being a discrete pulse response, and a time interval of a starting sample position of the peak window relative to a starting point of the pulse response sequence being taken as a starting delay time corresponding to the discrete pulse response.

3. The method for implementing an audio delay effect based on a sequence of impulse responses according to claim 2, wherein, The energy value of the signal segment in each analysis window is calculated according to the following formula: wherein is the audio sample value within the analysis window having the starting point, has a value range of 0 to , is a preset analysis window length, represents the energy value of the signal end within the analysis window having the starting point.

4. The method for implementing an audio delay effect based on a sequence of impulse responses according to claim 3, wherein, based on the initial energy value sequence, finding N discrete peak windows, the signal segment corresponding to the N discrete peak windows being a discrete pulse response, and a time interval of a starting sample position of the peak window relative to a starting point of the pulse response sequence being taken as a starting delay time corresponding to the discrete pulse response, comprising the following steps: (i) inputting the initial energy value sequence; (ii) finding an analysis window with the maximum energy value in the current energy value sequence as a peak window found this time; (iii) recording a time interval of a starting sample position of the peak window relative to a starting point of the pulse response sequence as a starting delay time corresponding to the discrete pulse response, and taking audio data starting from the starting sample position of the peak window and having a length of the analysis window length from the pulse response sequence as a discrete pulse response extracted; (iv) in the current energy value sequence, centering on the peak value window found this time, setting the energy values in the range of at least one analysis window before and after the peak value window to zero or marking them as invalid, obtaining a new energy value sequence, updating the current energy value sequence, and returning to step (ii) until N discrete impulse responses and the starting delay time corresponding to each discrete impulse response are obtained.

5. Apparatus for implementing an audio delay effect based on a sequence of impulse responses, characterized in that Comprise: A first module for inputting an impulse response of audio data of a desired delay effect; A second module for preprocessing the impulse response of the desired delay effect, extracting N discrete impulse responses and the starting delay time corresponding to each discrete impulse response, and determining the main period of the impulse response sequence, wherein determining the main period of the impulse response sequence comprises: for each discrete impulse response, finding the position of the maximum amplitude absolute value in the audio data corresponding to the discrete impulse response, and taking the time interval of the position of the maximum amplitude absolute value relative to the starting point of the impulse response sequence as the peak delay time of the discrete impulse response; calculating the difference between the peak delay times of all discrete impulse responses; and counting the peak value of the difference value, taking the peak value as the main period of the impulse response sequence; A third module for inputting an audio signal to be processed; A fourth module for convolving the input audio signal with each discrete impulse response respectively to generate a convolution signal corresponding to each discrete impulse response; a fifth module, configured to calculate an actual delay amount corresponding to each discrete impulse response based on a starting delay time corresponding to each discrete impulse response, a main period of the impulse response sequence, and a set adjustable target delay time, wherein the actual delay amount corresponding to each discrete impulse response is calculated as wherein denotes the starting delay time corresponding to the nthdiscrete impulse response, D denotes the main period of the impulse response sequence, and d denotes the set adjustable target delay time; A sixth module for delaying the convolution signal corresponding to each discrete impulse response by the corresponding actual delay amount to output N signals; A seventh module for mixing the output N signals to generate a final delay effect output signal.

6. A guitar effects processor characterized by, The guitar effecter applies the method for implementing an audio delay effect based on an impulse response sequence as claimed in claim 1, and the method for implementing an audio delay effect based on an impulse response sequence is preloaded in the DSP processing unit of the guitar effecter.

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