Tips & Tricks — SPL TwinTube Processor Plug-In

June 14, 2013 9:35:48 PM PDT

The TwinTube combines two essential tube effects — Saturation and Harmonics — in a single processor. Its two fully independent stages — which can be run together or separately — provides an exceptionally wide-ranging palette of sonic shaping, from smooth and creamy overdrive to deep, growling saturation, with a range of harmonic overtones to add warmth. It’s a sound that simply can’t be achieved using typical EQ.

Luckily, SPL has brought the distinctive features, sound, and character of the original TwinTube hardware to the UAD Powered Plug-Ins platform. Here’s some tips and tricks on how to get started with the SPL TwinTube Plug-In.

Learning The Controls

Let’s start by looking at a few of the notable controls on the SPL TwinTube Plug-In:


Harmonics Controls

The Harmonics section adds a special circuit for overtone processing that reacts dynamically to the incoming signal. Using the Harmonics control, you can adjust and enrich the overtone processing intensity across four frequency settings (2, 3, 6, and 10 kHz) as well as the overall effect. The result is an intensified presence that adds a sense of “air” and space to your sound — bringing a vocal or instrument forward in a mix.

Saturation Control
In the hardware version of TwinTube, saturation is created by pushing the tube beyond its normal limits. This causes a gradual building of harmonic distortion, accompanied by limiting that has been compared to analog tape distortion. It can be employed to subtly fatten sounds when applied sparingly, and to add warm overdrive coloration when cranked up.

Storing Your Settings

Much faster than with the usual save and recall presets dialogs, settings can be stored and recalled by just one click. Settings A, B, C, and D can be included into the automation of host applications to apply different sounds to different parts of a song or project.

In Use

Adding the SPL TwinTube plug-in to the master channel will enhance the overall warmth of the mix and give it a feeling similar to nice tape compression. Adding just a touch of harmonics will give the mix some air and enrich the high frequencies.

You can also use the TwinTube on individual tracks to help shape and place the track in the mix. This is a popular approach and where the TwinTube really shines.

I recommend using TwinTube as one of the first plug-ins in your signal chain as it has a great influence on the dynamics of the track. Think about the frequencies you wish to enhance and then turn the Harmonics knob up until you like the sound. Once you feel a noticeable difference in the sound and its presence, play around with the Harmonic frequency switches in order to find out whether your initial choice stills sounds the best to you.

Next, start dialing in the Saturation and feel what it does to the sound. With vocals, find that spot where the voice starts to sound warm, full, present, and has that feel of slight tube compression. This quality creates a dynamic vocal that is easy to fit in the mix.

Make sure to check your gain from time to time. If applied correctly, the difference in gain between the unprocessed channel and the processed channel should be negligible. While the Harmonics control will definitely change the perceived loudness of your mix, the actual volume will remain the same. The Saturation control is a different beast, however. At the most extreme level, output level may increase by approximately 6 dB, so if you use a lot of saturation, you may actually have to adjust the output gain.

Vocals (Click to expand)

Guitar (Click to expand)

Final mix (Click to expand)

Mixing Tips for TwinTube

In mixing, there is no truth — only taste — so the following mixing tips should be treated as guidelines rather than actual rules. They reflect my personal experience and taste, with settings that correspond to specific tracks and sounds, so feel free to use these settings as a jumping off point for your own sound.


TwinTube works wonders on vocals. When done correctly, further EQing oftentimes is not even needed to get the vocals to the front of the mix.

For female vocals, make sure the Harmonics switches are set to 10 kHz, and dial the Harmonics control in to about 2 o’clock, with the Saturation at about 8 o’clock. Listen and tweak the Harmonics settings to find out what complements your specific voice the best. For most female vocals, setting the Harmonics switches at 10 kHz should be the ticket, but if the voice is slightly deeper, try going for 6 kHz. For male vocals, try a 2, 3, or 6 kHz setting, depending on the character of the voice.

Acoustic Guitar

The Harmonics controls are especially good for enhancing any picking sounds, while the Saturation helps with compression, warmth, and limiting. Start with the Harmonics switches at 6 kHz, carefully dial in some Saturation to the 1 o’clock position, and add some Harmonics to around 1 o’clock as well.

Kick Drum

It’s amazing what the TwinTube can do on a kick drum, especially in conjunction with the SPL Transient Designer Plug-In. In addition to increasing body and warmth, the Saturation acts as a compressor, making the kick punchy and present. The Harmonics will give the drum that click you sometimes need in a tight groove.

Final Mix

To bring air and analog warmth to your final mix, slap the TwinTube on the final mix bus, dial the Harmonics switches to 6 or 10 kHz, and dial the Harmonics control to around 2 o’clock. Then slowly (really slowly) bring up the Saturation and feel out the level you like.

There are a multitude of applications for the SPL TwinTube plug-in, and neither this article nor any one single person can cover it all. But one rule of thumb is always useful — experiment as much as possible, be open-minded, and mix, mix, mix!


— BJ from SPL