JPH046080Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a reverberation adding device, and uses multiple delay circuits with equal delay times to obtain characteristics that are approximately close to ideal reverberation characteristics, with a long period at the beginning and short periods from the middle to the latter half. The purpose of the present invention is to provide a reverberation adding device that can add reverberation.

FIG. 1 shows a block system diagram of an embodiment of a conventional reverberation adding device. In the figure, an audio signal input to terminal 1 is taken out from terminal 2 via resistors r ₁ and r ₂ , while a mixing amplifier 3, a delay circuit using BBD (hereinafter referred to as BBD) 4, and a feedback circuit It is delayed in loop 5 and taken out from terminal 2. This one has a loop delay time of T due to BBD4.
Then, the attenuation characteristic of the signal taken out from terminal 2 is as shown in Fig. 2, and the delay time nT (n=1, 2,
3, .

Incidentally, as shown in FIG. 3, the natural attenuation characteristic for obtaining a reverberation effect is preferably a characteristic in which the period is relatively long at the beginning of reverberation, and the period gradually becomes shorter as time passes. FIG. 4 shows a block system diagram of another example of a conventional device capable of obtaining damping characteristics close to those shown in FIG.

In FIG. 4, the signal from the amplifier 3 is delayed and extracted through a loop of DDBs _{6 1} , 6 ₂ . . . 6 _o having different delay times, a resistor R _op , and a feedback circuit 5. The resistors R ₁₀ , R ₂₀ , . The delay times of each of BBD6 ₁ to 6 _o are set so that they are not integral multiples, and are set to R ₁₀ <T ₂₀ . . . <T _op .

In this case, each delay time of BBD6 ₁ to 6 _o is T ₁
〜T _o , the amount of feedback in the feedback loop of the resistor R ₁₀ with the minimum resistance value is large compared to other loops, so the delay time T ₁ of BBD6 ₁ that returns through the resistor R ₁₀
The attenuation characteristics as shown in FIG. 5 are obtained by a complex combination of reverberation caused by the delay times T ₂ to _{T 0} . However, this method requires many BBDs, each with a different delay time, and the reverberation period is dominated by the first stage loop, making it difficult to make the initial reverberation period sufficiently large. There were drawbacks such as the smaller the number, the stronger the two tendencies were.

The present invention eliminates the above drawbacks, and the sixth
One embodiment will be described below with reference to the drawings.

6 and 7 respectively show a block system diagram and a specific circuit diagram of an embodiment of the reverberation adding device according to the present invention, and in each figure, the same components are designated by the same numbers and symbols. All BBDs used in the present invention have equal delay times, and the ones shown in FIGS. 6 and 7 use two-stage BBDs. An appropriate number of BBDs may be provided depending on the desired damping characteristics.

BBD7 ₁ and 7 ₂ are connected in series, and their connection point is connected to the input of feedback circuit 5 via feedback resistor R ₁ , while the output of BBD 7 ₂ is connected to the input of feedback circuit 5 via feedback resistor R ₂ . It is connected to the. BBD
If the number of stages is greater than this, the number of resistors may be increased accordingly, and in either case, the relationship is set such that R ₁ >R ₂ >.... The other configurations are the same as the conventional device.

The circuit shown in Fig. 6 is connected to amplifier 3, BBD7 ₁ , 7
₂ , resistor R ₂ , feedback circuit 5, closed loop with resistor r ₂
(1), amplifier 3, BBD7 ₁ , resistor R ₁ , feedback circuit 5,
Closed loop (2) with resistance r ₂ , BBD7 ₂ , resistance R ₂ , R ₁
Let's consider the closed loop (3) divided into three closed loops. If each delay time of BBD7 ₁ and 7 ₂ is T, then in loop (1) only, the signal is BBD7 ₁ and 7 ₂
The period is 2T, 4T, 6T, ... 2nT (n = 1, 2, ...
). Next, in loop (2) only, the signal passes through only one _BBD71 and is extracted, so the period is 1T, 2T, ... nT, and this loop (2)
When used alone, only the characteristics similar to those of the conventional device shown in FIGS. 1 and 2 can be obtained.

However, if we consider these two loops (1) and (2) as a combination, in an even period of 2nT, the output of loop (2), which has a large resistance R ₁ , and this loop (2)
Since the output of loop (1) that does not pass through is combined, the combined output level is relatively high.
In the odd cycles of 3T, 5T, ..., the signal that has passed through the loop (2) with the resistor R ₁ is always taken out, so its level is relatively small, and the attenuation characteristics of the loops (1) and (2) are as follows. The result is as shown in FIG.

In this case, if the value of resistor R ₁ is too small, the output of loop (2) will be greatly involved, and the 8th
As is clear from the figure, the odd-numbered cycles caused by loop (2), especially the initial level of reverberation, are greatly involved, resulting in the
The characteristic attenuation becomes close to that of a period of nT, and does not have the ideal attenuation characteristic shown in Figure 3, in which the period at the initial stage of reverberation is large and the period gradually becomes smaller as time passes.

In addition, since the level of odd-numbered cycles in the early stage of reverberation is relatively high, there is a clear transition from reverberation with an even-numbered cycle of 2nT to reverberation with a cycle of nT that includes odd-numbered cycles, making the reverberant sound unnatural. It is.

However, in reality, there is a loop (3) in addition to these two loops (1) and (2), so the output from loop (1) actually includes the signal that passed through loop (3). Therefore, even if the value of resistor R ₁ is set to a relatively large value, the combined output level of loops (1) and (3) can be made large, and by setting the value of resistor R ₁ to a large value,
As shown in FIG. 9, the level of odd-numbered cycles at the initial stage of reverberation can be kept low. As a result, it is possible to obtain characteristics that are closer to the ideal characteristics shown in Figure 3 than the characteristics shown in Figure 8, and moreover, in the early stages of reverberation, the level of odd-numbered cycles is slightly lower because loops (2) and (3) are combined. However, the transition from reverberation with an even number period of 2 nT to reverberation with a period nT including odd number periods is not as clear as in the case shown in Fig. 8, and a natural reverberant sound can be obtained.

As is clear from Figure 9, in the early stages of reverberation, the period
2nT, and from the middle to the end of the period, a reverberant sound with a period of nT can be obtained, and characteristics substantially close to the ideal characteristics shown in the third diagram can be obtained.

As mentioned above, the number of stages of the BBD is not limited to two, but may be set as appropriate depending on the desired attenuation characteristics. determined (eg 3:1 for 3 BBDs).

Also, the resistance values of resistors R ₁ , R ₂ ... are R ₁ > R ₂ >...
It is not limited to..., and may be set as R ₁ ≒R ₂ ≒ depending on the number of BBD stages and desired attenuation characteristics.

As mentioned above, the reverberation adding device according to the present invention has a plurality of delay circuits connected in cascade, each having an equal delay time, to the input terminal, and a feedback resistor whose value is larger or approximately equal to that of the previous stage at each connection point. Since one terminal of the feedback resistors is connected in parallel to create a closed loop equal to the number of delay circuits, and the other terminal of each feedback resistor is connected in common, the period is relatively long in the beginning, and the period is relatively short from the middle to the latter half. It is possible to obtain reverberation with a ratio according to the number of stages in the short delay circuit,
Compared to conventional devices that use multiple delay circuits, each with a different delay time, and are provided with a feedback resistor whose value is set to be smaller in the previous stage, it is possible to use the same type of delay circuits. It has features such as being able to be constructed at low cost, allowing for a large initial period of reverberation, and being able to obtain characteristics substantially closer to ideal reverberation characteristics than conventional devices.

[Brief explanation of the drawing]

1 and 2 are block diagrams and reverberation characteristic diagrams of an example of a conventional device, respectively. FIG. 3 is an ideal reverberation characteristic diagram, and FIGS. 4 and 5 are block diagrams of other examples of conventional devices. A system diagram and its reverberation characteristic diagram, Figures 6 and 7 are a block system diagram of an embodiment of the device of the present invention and its specific circuit diagram, and Figure 8 is a diagram when the two closed loops in Figure 6 are considered. The resulting reverberation characteristic diagram, FIG. 9, is a reverberation characteristic diagram obtained by the device of the present invention. 1...Input terminal, 2...Output terminal, 5...Feedback circuit, ₇₁ , ₇₂ ...Delay circuit using BBD, _R1 ,
_R2 ...Feedback resistance.

Claims (1)

[Scope of utility model registration request] A plurality of delay circuits each having the same delay time are connected in cascade to the input terminals, and one terminal of each of the feedback resistors whose value is larger or substantially equal to that of the previous stage is connected in parallel to each connection point. A reverberation adding device in which a number of closed loops are provided, and the other terminals of the respective feedback resistors are commonly connected and connected to an output terminal.