Summing Mixer
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Buying a summing mixer for the studio or recording at home
If you're thinking of buying a summing amp, you probably already know a thing or two about studio gear. Of course, there are still a few things it's good to know: The main question producers ask themselves nowadays is "Do I even need a summing mixer? Or will the DAW do?" And summer isn't always summer; there are devices with different features in a range of prices.
This compact buyer's guide has been written specifically to help you find the right summing mixer for your needs. In our expert guides, there's much more information for anyone interested in studio gear and recording techniques.
If you have any specific questions about our range of summing mixers, or studio equipment in general, the Thomann Studio department will be happy to help, be it in writing at studio@thomann.de, over the phone on +49 9546 9223‑30, or in person in our store.
Of course, our service isn't limited to pre-sales advice: We offer our 30‑day money‑back guarantee on every item we sell. And for long term peace of mind, there's the 3‑year Thomann warranty.
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What is an (analogue) summing mixer?
An analogue summing mixer is often simply called a summing unit, summing amp, or simply a summer. The principle is straightforward:
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A summing mixer has many inputs and usually just two outputs. The audio signals are combined – in other words, summed.
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Unlike DAW software, this summing process is entirely analogue.
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Analogue summing mixers are, fundamentally, standalone devices for fulfilling one of the key functions of a mixing desk – combining signals.
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The difference between external summing and DAW summing is sometimes described using the terms ITB (In The Box) for DAW‑based mixing and OTB (Out of The Box) for summing amps.
What do you need an analogue summing mixer for? Does it sound better than a DAW?
Even the simplest audio software is perfectly capable of mixing signals together. Anyone using an external summing mixer is doing it for technical reasons or for improved audio quality.
When summing is done digitally, it means – put simply – calculating audio information with a limited number of values. Admittedly, digital resolution is quite high, but the actual number of values used to represent a signal still decreases during the mixing process. For example, after every standard fader in a DAW, a process known as truncation takes place: In simple terms, the fader's position is multiplied by the value of the signal. The resulting number is, however, too long for further processing, so it has to be shortened. This causes a loss of detail, and imprecision in the digital signal can lead to distortion. Analogue technology doesn’t have this limitation – in principle, the values of analogue‑mixed signals can be infinitely precise.
Furthermore, historically speaking, mixes have been created on analogue consoles for decades – and it's that sonic character that is being combined in and passed through a summing mixer. Indeed, many analogue summing mixers deliberately add their own unique analogue character to the resulting stereo signal, often by way of special transformers, for example. There are even tube summing amps available, which is to say units with valves placed before the stereo output.
Many users describe audible improvements when mixing through an external summing mixer instead of purely in a DAW, such as:
- a more natural sound
- a tone closer to high‑end analogue large‑format consoles
- greater level of detail
- fewer unwanted distortions
- intentional harmonic distortion when desired (often perceived as "warmth")
- a clearer stereo image
- tighter bass
- a less "harsh" overall sound
How do I integrate an external analogue summing mixer into a DAW?
Individual signals are routed to separate outputs on an audio interface. The output of the summing mixer is then routed back into the DAW, where it forms the master bus that's also used for monitoring. For larger projects, it often makes sense to send partially premixed (stereo) subgroups to the summing mixer. Typical examples include:
- drums
- guitars and bass
- keyboards
- send effects (reverb, delay, etc.)
- backing vocals
- lead vocals
One final thing that can make a difference us whether the summing mixer has level controls for its channels or not. If it doesn't, the actual balance between signals is still set within the DAW.
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How do summing mixers differ? What should you look out for when buying one?
One key parameter here is the number of channels: As with analogue mixing desks, common configurations are 8, 16, 24 or 32 inputs. For space reasons, the inputs are almost always implemented as D‑Sub connectors, which are connected via studio multicore cables.
Occasionally, you'll find insert points that allow additional analogue hardware such as compressors or equalisers to be integrated. Much rarer are dedicated subgroups or AUX sends, which you'd need, for example, if you want to apply the same reverb to multiple signals.
Some summing mixers only offer mono inputs, but include a pan control to position the signal between left and right. Others feature stereo inputs, and some offer a mix of both.
Some summing mixers simply combine the incoming signal levels directly, while others include level controls, much like the channel faders on a mixing desk. However, summing mixers with adjustable levels come at the cost of losing total recall: When you load up a different song to mix in your DAW, you have to manually reset the controls to match that project.
To partially replace a mixing desk, some summing mixers include a simple monitoring section, allowing speakers or headphones to be connected directly.
And because running the overall level too low in an analogue system can introduce noise, while running it too hot can cause excessive, unwanted distortion, some summing mixers are equipped with level meters.
Differences: summing mixer vs mixing desk
Summing mixers are specialised tools, while mixing desks are much more comprehensive interfaces, offering a much wider range of functions. For typical DAW‑based workflows, however, you often don't need all of that functionality. Conversely, if you've paid for a mixing desk's entire feature set, you'll usually want to actually make use of them all too: equalisers, microphone preamps, and complex routing and monitoring options are just some examples.
Which manufacturers make summing amps?
The mixing console circuits developed by Rupert Neve are considered classics. It's therefore no surprise that summing mixers such as the Neve 8816 Summing Mixer and the Rupert Neve Designs 5057 Orbit are among the most popular choices.
Another important player is SPL, whose SPL MixDream XP Mk2 is a comparatively affordable option in this category. Dangerous Music, Heritage Audio, Antelope, and Tegeler also manufacture summing mixers.