What Are the Features of a Feedback Suppressor?
A Feedback Suppressor is an audio signal processing device used in the signal path of a live sound reinforcement system. It prevents audio feedback by adjusting the decay time and attack time of the feedback signal. The most common applications of a Feedback Suppressor include preventing audio feedback in loudspeakers and in music recording studios. It is also useful for use in live concerts. To learn more about the features of Feedback Suppressor, read on.
Dynamic filters
The Feedback suppressor has two modes of filtering: Standby and active. The standby mode reduces the time before feedback is detected, while the active mode increases the time before feedback is suppressed. Both modes are adjustable. You can adjust the Hold Time manually, or use the Up and Down Arrows to change the values. The active mode sets the time before the Dynamic Filter persists, and the standby mode sets the time before it is cleared. If you want to disable feedback suppression for a specific period, you can change the hold time.
In the active mode, the FBS is loaded into the processor block. The dynamic filters detect feedback frequencies and counteract them. This approach is ideal for systems that do not have feedback protection, but still need a feedback suppressor. This approach is known as the Load and Go mode and works on both systems. If you don’t use feedback protection, you can set the dynamic filters on the Load and Go mode.
When you disable the lock setting, the dialog will close. This will leave the five dynamic filters open. To engage the Bypass feature, click the Bypass button. This procedure will cause some feedback while it clears all the dynamic filters. You may have to press the Lock button a second time to make the Bypass mode active. The Bypass setting retains the detected filters but leaves the fixed ones in play. This feature is especially useful when you don’t want to deal with feedback all the time.
The lock option locks the current set of dynamic filters, preventing them from being overwritten. In addition, the Bypass option sets all dynamic filters to Bypass mode without affecting the fixed filters. There are many other options available, but the main function of the Feedback Suppressor is to eliminate feedback. However, it is vital to know the difference between the two modes, so you can make an informed decision. It is also crucial to note that the Lock setting is only temporary and intended for the initial setup of FBS.
Attack time
The attack time of a feedback suppressor sets the amount of time that a dynamic filter is active after feedback is detected. The longer the attack time, the fewer chances the dynamic filter will respond in a manner that you don’t want. On the other hand, the shorter the attack time, the less time feedback will be suppressed. Depending on your material, you can adjust these settings to optimize your workflow.
The attack and release time of a feedback suppressor are important to optimize the sensitivity of the hearing aid. These parameters determine the amount of gain that a hearing aid will provide, and they are measured in milliseconds. An attack time of about five milliseconds and a release time of 45 milliseconds will produce a steady-state output level of approximately 90 dB SPL. On the other hand, a longer attack and release time will result in less distortion and a comfortable listening level.
Decay rate
Determining the decay rate of a feedback suppressor is crucial for the proper control of the signal. A feedback suppressor is a device that reduces the feedback effect by reducing the amplitude of the emitted electron. The decay rate can be calculated by measuring the amplitude of the feedback signal. A decay rate greater than one would result in a weaker suppressor. For example, if a feedback suppressor can reduce the amount of emitted electrons by half, the effect of the feedback is significantly reduced.
Detection of feedback whistles
The term “feedback” refers to the high-pitched whine generated when a signal loop develops between an amplifier and a sound system’s input. The effects of feedback can be detrimental to your sound system’s loudspeakers, including distorted sound. Common sources of feedback include singers’ microphones, wireless microphones wandering into danger zones, improperly placed floor monitors, and air temperature fluctuations. If you’re having trouble with feedback in your sound system, try the following solutions:
The Automatic Feedback Suppression (AFS) algorithm monitors incoming audio for feedback, then places narrow notch filters at each frequency to reduce the gain of that frequency. These filters carve out the offending frequency with pinpoint accuracy while preserving the surrounding frequency spectrum. This entire process takes milliseconds, and is complete before a human ear can detect the anomalies. Detection of feedback whistles with a feedback suppressor can prevent feedback noise from affecting the quality of your performance.
The potential for feedback with harmonics must be balanced against weak harmonics in non-feedback sounds, as these will blur the area of accurate discrimination. A feedback whistle can also be a symptom of a poorly-sealed earmolds or tubing. In either case, a feedback suppressor can help you stop the feedback, or eliminate it altogether.
Another way to detect feedback whistles is to use a specialized microphone. The sensitivity of the microphone is a key factor in determining the frequency of feedback. Usually, the noise is created due to a mechanical malfunction. This malfunction usually requires a device to be returned to the manufacturer for service. If the malfunction is caused by an error in the hearing aid, a clinician can perform a minor repair in the office.
Using a feedback suppressor
A feedback suppressor is a device that processes audio signals to remove unwanted frequency peaks in a system. The suppressors available for live sound reinforcement use various techniques to achieve the desired effect. The oldest is frequency shifting, which introduces a varying shift in frequency to the system response. Typically, frequency shifting is implemented by using a frequency mixer. However, this technique only achieves modest gains before feedback, and causes noticeable pitch distortion. Another technique is adaptive filtering, which models the transfer function of a sound reinforcement system and subtracts the reinforced sound from the inputs.
A dedicated feedback suppressor provides additional headroom, often as much as 10dB. It uses a bank of narrow notch filters to detect feedback frequencies and deploy a filter to cut out the unwanted signal. Once connected to a signal, the feedback suppressor is a very versatile piece of gear, which is very convenient in a live setting. The feedback suppressor is also easy to use and flexible. Rather than having to manually select a frequency, it simply locks onto the feedback frequency and notches out the unwanted signal.