Podcast Academy

By Paul Figgiani

My first direct exposure to Aphex signal processing gear was based on the complexity of a large scale project that I was hired to produce some time ago. This project consisted of multiple conference sessions that were recorded directly to mini-disc. Each segment contained problematic dynamics and variations in levels that in most cases would create a potential post production nightmare. The audio required RT transfer to my workstation.

Prior to this, Doug Kaye consistently referred to the Aphex 320a Compellor™ as his IT Conversations “secret weapon.” This was the processor that Doug used to pre-process most of the submitted raw source audio for IT Conversations prior to post production, and slated for subsequent publication. The Compellor™ is a classic device that performs compression, leveling, and limiting. It was exactly what I needed to maximize efficiency for the project at hand. I purchased one, and Aphex became an instant favorite.

It’s no secret that the Aphex 230 Vocal Processor has become the dream piece within this community. It is a fantastic device that offers high quality results. However in my opinion there are two potential obstacles: cost and complexity.

In terms of cost, the $600+ price tag may be considered too steep for those who may be on a tight budget. It’s important to note that the Aphex 230 is a single channel device. If a producer requires multiple channels of independent processing, individual 230’s would be necessary. Once again, cost becomes a major concern. Please note that I am not suggesting that this device is overpriced by any means.

In terms of complexity, I honestly believe that *most* of the producers opting for the 230 are finding that it is a professional device that requires a good amount of understanding at various levels in audio [vocal] processing in order to achieve optimum results. Lastly, knowledge of proper system integration is essential. The point is that it may not be for everyone.

Considering these factors, I often recommend dual channel dynamics processors as opposed to single channel vocal strips. I realize they do lack processing flexibility. However the dual channel processor approach is worth considering if you need to process two mics independently with very little fuss. Aphex offers a wonderful variation to the 230. I’m referring to the 240 Advanced Gating and Compression System.

Let me stress that In would be irresponsible for me to compare the Aphex 240 to the 230 vocal strip. We are dealing with devices that are very different in design and concept. My intention is to point out that the 240 will provide excellent results in taming dynamics, and it will help alleviate problematic ambience without adding any fancy enhancements to your voice. So let’s take a closer look at the Aphex 240.

I must share with you a particular issue that really impresses me: clear and well thought out technical manuals. I can report that Aphex meets this standard. Their component manuals are just about the best I have ever seen. Besides thorough explanations of parameters, integration suggestions, and recommended settings, these booklets include detailed audio processing scenarios that will entice the reader to develop proprietary implementation concepts. Additionally, a list of external reading suggestions are clearly stated. I’m convinced these references will help the user to maintain maximum performance. If by chance you purchase pre-owned Aphex gear, all manuals are readily available for $10 US. Read their manuals!

Main Controls

The front side of the processor consists of four control and reference areas: Channel One processing parameters, processor Switching/Linking, Channel Two processing parameters, and Reference Metering. Each independent channel consists of a Logic Assisted Gate™ and EasyRider Compressors™. Aphex states the relative left to right order of the Gate and Compressor is intentional. For best results, the gating should be configured prior to compression.

Logic Assisted Gate™

Most gates rely on the sheer power of a signal in order to open. The problem with this is that in many instances, short transients and weak sound waves fail to open the gate efficiently due to their lack of power. The Logic Assisted Gate™ has been designed to provide 100 percent consistency and unparalleled accuracy . Logic Assistance alleviates inconsistent gating due to zero dependence on the power of a signal.

Available Parameters

Threshold: The trigger point. A signal level that moves above this setting will open the gate. Once the signal drops below the threshold, the gate closes. The signal will be partially reduced or totally eliminated.

Attack: Determines how quickly the gate opens once the signal moves above the threshold. In most cases [voice], fast attack times are recommended

Hold: Aphex states: “the Hold setting should always be at least equal to the Attack setting to insure the logic properly assists the Attack function.”

Release: Determines how quickly the gate closes once the signal drops below the threshold.

Depth: Controls the amount of signal that may or may not be apparent once the gate closes. At the 80dB setting, the gate will attenuate 100 percent of the signal. Less Depth will control the precise level of attenuation.

EasyRider Compressor™

I have good news. If you found the Logic Assisted Gate™ references to be a bit complex, my guess is that you will not experience the same level of confusion when studying the concept and implementation of the Aphex EasyRider Compression™ system. This is due to an interesting subtraction of typical compression parameters.

Most compressors offer threshold, ratio, attack, release, soft/hard knee, and gain compensation settings. A potential “nightmare to the novice”, so to speak. The Aphex 240 presents the user with a total of three compression parameters that in my opinion will eliminate the arduous task of achieving transparent compression with spoken word.

EasyRider Compression™ feature’s what I refer to as adaptive attack and release. The system analyzes the energy level of the audio based the relationship between its peak and average loudness, and makes adjustments accordingly based on the variations in the audio characteristics.

Available Parameters

Drive: Controls the signal level that drives the compressor. As this setting is increased, gain reduction is increased. This translates into a higher level of compression

Speed: This controls the speed of the internal time constants

Output: Compression attenuates a given signal. This setting controls the final output level

Compressor Specifications

• Program dependent Attack and Release
• 3:1 Compression Ratio
• Fixed Threshold
• Medium Hard Knee

Metering and Control

The 240 ’s metering system displays independent gating and compression gain reduction values for each channel. A green bar specifies compression gain reduction. Gating gain reduction is specified by a red dot. When this dot becomes “nested” within the green bar, the dot changes to yellow.

By disengaging the Stereo Link feature, the 240 can function as a dual channel processor. This option will provide independent processing for two channels.

Connection Panels

The channel I/O panels located on the back of the 240 are identical. Jacks include balanced XLR and TRS inputs, and impedance balanced XLR and TRS outputs. Aphex states that these outputs are driven from the same output circuit, however they can be used simultaneously to drive independent devices. Operating level [+4dBu/-10dBv] is switchable, and a key insert jack is provided as well. Custom wiring instructions are included in the manual in order to support unbalanced connections.

Thoughts, Setup, and Use

I think there are a few misconceptions within this community in terms of what a noise gate is capable of. It is important to note that noise gating is not a magical process that will totally remove problematic room ambience. Actually - it can do this, when the gate is fully closed. However, once the input signal passes the threshold and the gate opens, the apparent noise will once again be audible.

Using spoken word as an example - If a recording session is conducted within an environment that includes a good amount of noise, aggressive gating will be detrimental. Why? Each time the host begins to speak, the noise will “explode” as it is reintroduced. My recommendation is to address the problematic ambience at the source. This will help you to maintain a more natural gating effect.

I connected the processor using a balanced XLR insert cable to an available channel on a Mackie mixer using a Shure SM7B broadcast microphone. During tests, setting the Threshold was easy: I spoke naturally and found the exact point where sensitivity was optimal. The Attack, Release, and Hold helped me to fine tune the efficiency of the gate.

The Depth parameter on the 240 controls the attenuation of the gated signal. After a bit of experimentation, I found that I was able to create a much more natural effect by permitting low levels of noise to remain while the gate was fully closed. This alleviated the common sudden burst of noise that would surface as the gate opens if the closed state had performed 100 percent attenuation.

The EasyRider Compressor™ setup was trouble free. Keep in mind that I am familiar with the Drive setting and concept due to my familiarity with the Compellor™ 320a. This model shares a similar feature. I found that an approximate 8dB in gain reduction and a Speed setting weighted to “fast” resulted in audio that sounded smooth and not overly compressed.

Cooperation

The gating and compression stages of the 240 are designed to compliment each other while processing is engaged. The system gates the gain reduction of the compressor so that compression stops and is not permitted to release while the gate is closed, or if it is in the process of closing. This helps smooth compression during sound pauses.

Conclusion

Remember that my intension is to suggest this type of processor in order to help you maintain consistent dynamics, nothing more. The Aphex 240 is easy to use and it is capable of providing excellent, transparent results. If you are interested in developing a “signature sound” with the help of equalization, frequency filtering, de-essing, big-bottom and exciter characteristics, I would suggest that you seriously consider the Aphex 230 instead.

That being said, the Aphex 240 Advanced Gating and Compression System will serve you well, and it will introduce you to the wonderful world of proprietary processing and concepts developed by Aphex Systems.

The Aphex 240 sells for $499 US.

Photography by Paul Figgiani