Building an audio phase adjuster to adjust a range of signals

[ocacoustics]

My colleagues and I are building a phase adjuster for LFN (Low Frequency Noise) audio signals. Since we would like to be able to adjust a range of signals that encompasses a range of around 50-400 Hz, an op amp-driven, analog solution would not be economical, nor efficient. Since we need to be able to adjust a range of frequencies, we are looking at a digitally converted solution utilizing potentiometers. If a digital device is not feasible, can anyone describe how to construct an analog solution for real-time phase adjustment?

Has anyone had any experience in this area?
Does anyone know of any resources one can use to construct the aforementioned device?

Thanks in advance.

 

[WaterRocketBoy]

Sounds like you need a Digital Signal Processor to apply a complex Finite Impulse Response (FIR) filter to your sound. The taps of the FIR would be calculated by Fast Fourier Transform applied to the desired response, i.e. the gain and phase desired for each frequency in your range. The sampling rate of your system governs the number of amplitude/phase bins that will fall within the desired range of frequencies. An apodizing function must be applied to the desired response vector before applying the FFT. This is required to control undesired energy.

Your system must also have an analog input and output with appropriate (analog) anti-aliasing filters to reject products between the sample frequency and the signals being processed. Some mechanism must be provided to control the desired response vector from the controlling source (humans?).

 

[ravenprp]

It sounds like you have a clear goal in mind for your phase adjuster and have already explored different options. It's great that you are considering the efficiency and cost-effectiveness of your solution.

One possible analog solution for real-time phase adjustment could be to use a variable phase shifter circuit. This circuit would use a combination of capacitors and resistors to shift the phase of the signal. By adjusting the values of the components, you can control the amount of phase shift. This can be done for a specific frequency range by choosing appropriate component values.

Another option could be to use an all-pass filter circuit. This type of circuit can also be used to shift the phase of a signal, and by adjusting the cutoff frequency, you can control the range of frequencies that are affected. It may require some fine-tuning to achieve the desired results, but it can be a cost-effective solution.

As for resources, there are many online sources and books available on analog circuit design that could be helpful in constructing your phase adjuster. You can also reach out to electronics forums or communities for advice and support from experienced individuals.

I hope this information helps, and I wish you success in your project. Good luck!