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D. Dynamic Range 2
Published in Bob Katz, Robert E. Runstein, David Miles Huber, Bruce Bartlett, Jenny Bartlett, Danny Cope, Craig Golding, William Moylan, Roey Izhaki, Tom Hutchison, Paul Allen, Amy Macy, Russ Hepworth-Sawyer, From Demo to Delivery, 2013
Attack time is the time it takes for the compressor to implement full-gain reduction after the signal has crossed the threshold. Typical attack times used in music mastering range from 50 to 300 milliseconds (or longer on occasion), with the average used probably 100 milliseconds. Because digital compressors react with textbook speed, a digital compressor set to 100 milliseconds may sound similar to an analog compressor set to, say, 40 milliseconds; so it's probably better to remove all the labels on the knob (except slow and fast) and just listen! Release time, or recovery time, is how long it takes for the signal level to return to unity gain after it has dropped below the threshold. Typical release times used in music range 50–500 milliseconds or as much as a second or two, with the average around 150–250 milliseconds.18
Compression and Limiting
Published in Alexander U. Case, Sound FX, 2012
The concept behind attack time is straightforward: It should describe the length time it takes for the compressor to compress — the time it takes the gain change to reach the necessary level so that the user-defined ratio has been reached. An attempt to plot the gain of the compressor as it goes from its fully uncompressed state to fully compressed reveals the problem (Figure 6.8). The compressor might march directly from uncompressed to compressed (Figure 6.8a). It might begin compression slowly and accelerate into full compression (Figure 6.8b). It might begin attenuation quite quickly and approach the ultimate compressed state asymptotically (Figure 6.8c). It might wait some specified period of time and then snap instantly into compression (Figure 6.8d). Or, it might follow any path, however random, from uncompressed to compressed (Figure 6.8e). Attack time defies a single number description. Release time presents the same issue. The subtle variation in the shape of the gain change can have an audible result. In fact, this is part of what distinguishes one make and model of compressor from another.
The Mix
Published in Dave Swallow, Live Audio, 2012
Your attack and release settings work together and should be used together. They are audibly linked; once you start to change one, the other is affected because you are changing the way the instrument is working with the rest of the music. You should always start at the beginning of the waveform and work your way back. Set the threshold and ratio so that your compressor is in a constant state of compression, adjust the attack time, and then the release time. Once you are happy with how the compressor is holding your signal, adjust your ratio until you are happy with the amount of compression; then adjust your threshold until you are happy with when your compression is applied.
Security weakness of dynamic watermarking-based detection for generalised replay attacks
Published in International Journal of Systems Science, 2022
Changda Zhang, Dajun Du, Qing Sun, Xue Li, Aleksandar Rakić, Minrui Fei
To verify Theorems 3.1, 3.2 and 3.3, two finite-window-size tests (Huang et al., 2018) are, respectively, used to perform DW Tests 1 in (8) and 2 in (9), i.e. where and are two preset detection thresholds; T = 10 is the chosen window size. The values of and for simulation and experiments with are given in Table 3. Note that the reason of choosing a rather different is that it is expected to validate security weakness of DW-based detection even with big watermarking intensity. To further analyse the detection level, the detection rates and are defined as follows: where is the length of attack time interval (ATI); () is the size of () in the ATI.
Event-triggered resilient control for cyber-physical system under denial-of-service attacks
Published in International Journal of Control, 2020
Shan Liu, Shanbin Li, Bugong Xu
Figure 4 shows the event triggering time, the cyber state switching time and successful attack time. Figure 5 shows the state estimate and the transmitted state estimate after the event-triggered mechanism. We can see from these two figures that when the cyber system is at a better cyber state, which means there are less packet dropouts caused by the DoS attacks, the triggering happens less frequently, and the state estimate fluctuates more slightly.
An Attack on Hollow CAPTCHA Using Accurate Filling and Nonredundant Merging
Published in IETE Technical Review, 2018
Jun Chen, Xiangyang Luo, Jianwei Hu, Dengpan Ye, Daofu Gong
The attack speed is an important indicator to measure an attack method. The shorter attack time indicates that the security of a CAPTCHA scheme is worse. In addition, improving the attack speed of CAPTCHAs can reduce the time spent in the massive CAPTCHAs attack test.