Analog Summing – The Myth and The Fact

One of the many reasons I was so curious about analog summing before choosing the topic for my final thesis at Tampere University of Applied Sciences was that there was so much uncertainty and conflicting information over the internet about the matter. The discussion forums seem to be quite religious about it to be honest.

The Myth

This is the kind of picture you get when reading discussion forums and marketing punchlines.

  1. Analog summing improves sound quality of a mix
  2. It sounds like lifting a blanket from in front of your speakers
  3. Analog summing is non-linear and non-linearity is a good thing
  4. Digital audio sucks and makes life miserable
  5. Mixing is easier with analog summing

…all this is utter bullshit.

Many people have an opinion about analog summing without even having ever actually studied or tested what kind of audio effects it can introduce to a multitrack signal. I’m truly not the most professional person to tell about the effects, but I’m professional enough to be skeptical about things that are not certain facts and are just rumoured to be facts. In fact, in search for literature about analog summing, I didn’t find a single book telling anything useful about audio quality effects of analog summing. There were a lot of books that didn’t quite fit the criteria of being reliable sources of information. There were books that mentioned analog summing but didn’t explain a single thing about it other than stating that “some people like to sum tracks in the analog realm for more analog feel”, which doesn’t really mean anything.

There’s no such thing as analog realm or analog feel. These are just marketing words to make you buy stuff. I do like how analog mixers look like and how they work like, but that doesn’t mean the sound has a certain kind of a feel. Analog audio is just electric current. It does not think. You’re the one doing all the thinking and all feelings and realms are between your ears.

What do you need to do analog summing?

If the multitrack is in digital format (well mostly it is) you’re going to need a converter with a lot of channels. Analog summing is mostly done on 16, 24, 32 or 64 channel mixer so you need atleast the amount of analog outputs from the digital converter as you have on the analog mixer. On top of that you’ll need to convert the summed stereo output from the mixer back to digital with 2 channels of converters.

That is a lot of gear that can cost thousands, tens of thousands or even hundreds of thousands of money.

If you already have a studio with all the gear anyway, it is wise to use them to their full potential which sometimes means recording, mixing and summing with the same gear. However, some people buy analog summing mixers and converters just to take out a digital mix through an analog mixer as mix stems. I’d say it is not very practical and it’s quite expensive for what it does. Of course you can do whatever you want, but I personally would recommend against it. After all, a summing mixer is just a mixer that cannot be mixed on. Read further. I will explain myself.

Here’s my rule of thumb: The weakest link of every signal chain is always to most significant sound-wise and the first part of signal chain is the most important. In order to have a signal chain, every part must work as in pass audio.

So. When summing a digital mix with an analog mixer, you have multiple signal chains where the most significant part of those chains is the one that makes the most difference. In most cases, the digital converter will be doing the most difference. The conversion process can bring all kinds of effects to the sound that will not be magically healed by the summing process.

Disclaimer: The only thing I’m going to say about analog summing in a completely analog signal chain is that in a fully analog mix you have to do the summing anyway, so you can’t really say if it makes a difference because without summing there is no mix.

Sound quality and good sound

I’ve read it hundreds of times on discussion forums that the summing should be as clean as possible to truly make a difference. That would mean having the highest grade gear available. The best converters and the best possible mixer with the cleanest and purest signal path. This is a myth. The truth is, the better the signal chain is, the less it will degrade a signal. And, you can’t really improve quality by just routing through an audio device. Once a sound is recorded or synthesized, you simply can’t improve its audio quality after. You can shape the sound all you want, fix problems and even make it sound better, but you cannot improve audio quality.

There is sound quality and then there’s good sound. These are opposite sides of the same coin. Some of the best sound effects have been created unintentionally, like distortion effect for guitar. Guitarists at the time used what was available at the time, poorly designed guitar amplifiers that distorted badly at relatively low volumes. And guess what, it defined what we now think an electric guitar should sound like. It is what we think sounds good, but it has nothing to do with sound quality. In fact, it is quite the opposite. People often confuse sound quality with good sound.

So back to the summing!

There’s talk about analog summing in which many people say there’s something wrong with digital summing and it can be fixed using an analog summing mixer to sum the mix. This is just pure nonsense. In fact, when summing on analog mixer, you are most likely going to have to sum in digital multiple times to make stems which are then summed on an analog mixer. Of course if you have (can afford) enough channels to put every track on separate channel, then you can obviously justify doing that. If you can afford that, then why not? But when you’re on a budget, you’re not going to get rid of digital summing by buying a summing mixer. In my opinion, there’s no need either. There’s absolutely nothing wrong with digital summing unless you are using a software from the early 90’s. Even then, I doubt the summing was as big of a problem as other limitations.

So who am I to tell you anything about all this?

Well I’ve actually made tests about summing on an analog console made by Solid State Logic, using the newest Avid converters. I did some null tests and analyzed them using FFT-analysis. I also tried to hear differences. There’s no doubt differences exist between digital and analog summing and I even know why. Below are the most important things I found out.

20110810-img_0996

Edit 5.1.2017: Updated the picture. Yummy yummy!

The Fact

So what should one expect from analog summing?

  1. Analog summing degrades audio quality and adds non-linearities (a nicer word for noise and distortion)
  2. Panning in analog mixer is not as perfect as in digital mixer. This means that mix elements that are placed dead center in digital are propably going be slightly off-center in analog and it affects our perception and the acoustic summing of the speaker system. This also makes the low frequency content much more pronounced and the stereo image of the mix will appear slightly wider.
  3. Depending on how loud you go, there will be some peak compression due to limits of the hardware.
  4. Depending on sampling rate there will be high frequency loss due to reconstruction filter also known as the anti-aliasing filter which will limit the bandwidth of the signal to minimize any non-linearities that might happen in the conversion process.
  5. There will be some crosstalk, meaning the channels bleed through to each other and it will have an effect on panning positions.
  6. The conversion from and back to digital will introduce a small delay. Different converters can have slightly different delays due to inaccuracy of the sampling clock. This can effect phase relationships of the tracks.

There’s no such things that would magically improve sound quality or anything like that. All the effects you can hear are easily explained by doing tests and studying the subject. Many of these effects can be done inside your prefered digital audio workstation. The complexity of the effects is not propably as easy a task, though. You can add distortion and noise, pan things slightly off-center, use a stereo widener for that effect and so on. All these things can sound good, but under the hood they are degrading sound quality.

A really nice alternative for multitrack summing is to use just 2 channels and send your mix through them. You can save your money on the summing mixer and instead you can get a nice mix buss compressor or an equalizer, both of which will give you more for your money. When I did my tests, I also had versions summed with 24 channels and only 2 channels and the differences were small enough to not make a very noticable difference.

I can see why analog summing is popular and I don’t blame anyone for it. Personally I think it is only worth the money and trouble if your mixes are already so perfect that it is the only thing that you can do. Again: if you’re mixing analog, then it’s not a question of whether or not anymore.

Non-linearity. Such a nice word.

Many manufacturers of software and hardware make the word non-linearity to sound like an audio quality improvement. The truth is that non-linearity is just another word for noise, distortion and other unexpected changes in sound.

Many if not all known and respected manufacturers of software use this word all over the place. Especially with digital plugins that model analog mixers. Would you buy, for example, Slate Digital’s The Virtual Console Collection plugins if it was marketed like this..?

“Despite the digital revolution in the audio industry, many of today’s top commercial albums are still mixed on analog consoles. Audio engineers rely on analog mixing to provide the distortion and noise that digital mixing does not produce.”

..propably not.

Analog mixing is not about non-linearities even if you are told it is. It is more about being able work on the mix with a tool that makes it easier for you. Distortion is not what makes mixing easier. It’s the whole thing and being able to work on a mixing console instead of a mouse and a keyboard. After all, mixing console is an old invention and its primary use is to be used in mixing. It’s not really about the sound as much about having the right tool for the job. The summing part of a mixing console is just a required feature. You can’t mix without summing. In order to be able to play the mix through a pair of speakers the tracks need to be summed to a stereo output.

The more you use money on summing, the less it will make a difference. Atleast if you buy new stuff, which almost always strives for the best audio quality black on white. The summing itself doesn’t really sound like anything. If you don’t sum, then you can’t listen to the mix. Back in the day, the mixers that were used didn’t have as good sound quality as todays hardware. They had lower headroom, more distortion and noise and all kinds of stuff that we now think is the reason music back then sounded somehow better. Back then people propably truggled to get rid of the distortion and noise or atleast minimize it. We are in so much better position now, that we can actually tune the amount of these “non-linearities” to our liking and the tools are there, available for everyone.

But what I am seriously concerned about is how studio hardware and software is being marketed these days. When paired with increasing amount of home studio amateurs and semi-professionals that don’t have time to study things, it is very dangerous for the music industry to be based on lies and disinformation. Not before long the whole industry, even on professional level, will be based on misleading rumours and beliefs instead of facts and realities. I fear it can only lead to one thing: A decline of respect towards professional audio engineers. The ones who are responsible for the quality control of the whole music industry.

“Don’t believe what you’re told. Know only what you have confirmed to be true.” -Werihukka

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13 thoughts on “Analog Summing – The Myth and The Fact

    • I have no experience about external clocks for converters.
      In all honesty, I can barely notice much difference between decent and great converters.

      In an acoustically very well designed listening environment with very expensive monitoring, sure, I can hear differences in converters.
      Unfortunately music is not listened in places where differences between converters and external and internal clocks could be noticed at all.
      In a real life situation there are more important factors to take into consideration than converter clocks.

      In theory, if all your gear is the best there is and your studio is acoustically as perfect as it can be and people listen to the music only in unmastered 24-bit audio in a mastering grade studio environment, there might be a noticable difference. This is never the case, so it is irrelevant.

      All the best,
      Werihukka

  1. Great article. Re: External clocks, most designers agree that most converters are at their best with their own internal clock. Synchronizing to an extra clock, however fancy simply introduces a performance impediment. More money saved!

  2. The articel sounds like if the writer never worked on an analouge console, otherwise he would know how easy a mix on a console comes together – special the low end. Reaching the same result ITB is a pain in the a. Most ITB mixes sound non 3 dimensional, thin and flat. There is a reason why the full time mixing geeks still use consoles. Its sound and workflow. You dont have to spend big bugs to try it. Even one of the Allen an Heath ZED boards will do the trick, they have very good specs and you can use them for summing. Or take one of the Mackie VLZ…..

    • Console is better sounding: Yes. Console has better workflow: Yes.

      But when analog summing is taken out of context with mixing, sound and workflow, it does absolutely nothing to improve sound quality.
      Running digital tracks through bunch of resistors wired in a nice looking box is not going to do anything spectacular for example.

      I am currently building my hybrid mixing setup on a Midas console. Analog has character and it has a sound. But when talking of sound quality, it is not better than digital.
      If you can’t get good and “3 dimensional mix” within a digital workstation, then you have to start selecting tools more carefully and use them more wisely:
      An equalizer, a couple of good go-to compressors, delay and reverb. That is all you need for a good mix. Using analog gear forces you to think about mixing in a more simplistic way and it makes for better mixes. It does not have anything to do with summing, which is just a process of playing many tracks simultaneously through fewer channels.

      All the best,
      Juha-Matti

  3. So I realize I’m very late to this conversation. Long story short I’m a Grime/Hip-hop producer from a digital only realm. No shameless promotion I promise but PLEASE listen to my page below for no other reason than reference. I want to buy a Studer 779 or possibly the Revox C279 mixer for summing my busses. I’m a live sound engineer by trade and I test my tracks on sound systems fairly often and in comparison to people I know who use analogue summing IDK I can’t help but think I’m missing a little something. Granted I think I’m strictly talking about color and taste that is in a very subjective way but I do very much notice a “opened” sound to things that I know aren’t made in complicated ways. Not to mention I also seem to notice a louder sound to these same mixes that came threw analogue buss summing. IDK am I distracted by toys? I can’t help but think letting my kicks and snares touch pans and brightening them a bit wouldn’t help let me know if I’m kidding myself.

    • Hi, Chris. The article is very popular and the discussion is always open of course. I don’t think using analog gear is unjustified. Especially for a little bit of lo-fi crunch and “that something”. Quality of sound in case of artistic intention is secondary. What ever gear has sound that you want, I would say go with that.

      Probably adding a cool mixer and maybe some analog compression with the channel EQ’s is just what makes your work with music more enjoyable and results in better sound.

      One thing to keep in mind with old mixing consoles is the cost of the console and maintenance, and of course the need for more channels in digital to analog conversion.

      I would dare to say that more cost effective way to get more color to your tracks is to give the final mix a roundtrip through some quality analog compression, equalizer or even pair of channel strips.. and push the gear just a little bit to its limits, so it starts to sound “more analog” and distorted in a good way.

      I am fan of analog, but to be honest, my digital mixes already have enough color because of my love for use of distortion and saturation instead of compressors and limiters, that many times the analog is too much. The digital mixes are usually easier to tailor to my tastes. Analog gives nothing new unless I use it as primary tool for mixing.

      I have to say though that little boost in the low end and high end with analog equalizer sounds usually better to my ears than boosting with digital equalizers.

  4. Another late comer to the fold! I came across your post while trying to find out the best way forward in my musical recording journey.
    I am still very new to all of this and am just coming to terms with exactly what a ‘summing’ mixer is and what it isn’t…basically my new setup at the moment is as follows: a Soundcraft FX16ii mixer, 2 analog synths and an analog drum machine going into the mixer and everything going out and being recorded into a Tascam DP-24 multitrack recorder. Now the Tascam only has the ability to record 8 tracks simultaneously so I am unable to record all 8 voices from my drum machine plus the 2 from my synths but what I can do is record 2 mono channels out from the mixer onto the Tascam.
    Now I guess my question is that in terms of getting the best possible audio quality is this way a viable option or should I just bite the bullet and get an audio interface to record everything back into a DAW (I’ve done a pretty good job of steering clear of the computer thus far and I would like to continue for workflow reasons)???
    Also I would like to if not now but in the future be able to have everything recording individual stems so I can outsource any mastering as that is not where my skill set lies. I want to try and keep away from the computer as for me personally it is a major creativity blocker but I don’t want that to hinder the potential overall quality of my music.

    Kind regards,
    Kyle

    • Thank you for your comment. I would say simply avoid using anything that works as limitation to what you are trying to do. If working on a computer is a major creativity blocker, then I would avoid it.
      In my work it is necessary tool, but for you it might not be. Whatever works the best is the best setup. Sometimes simplicity is just right.

      All the best,
      – JMK

  5. So with what you said about all this analog gear degrading the sound quality and messing with the panning, this creates more “headroom” to push the boundaries of the music, no? Also I’m into popular music and it seems that all the song at least on the radio were mixed and mastered using analog at some point in the chain. Our ears are used to the sound and want more of what were used to. Digital does seem thin. Is it possible to push the boundaries of the music with just digital, people can tell the difference even listening on small systems subconsciously at the least? I’m sure with a nicer pair of monitors alone that would completely change the game for me. But is that enough to stand next to the records that are being listening to by millions of people around the world assuming the song/music quality is comparable?

    • Thank you for comment and the good questions to this discussion.

      Firstly, every professional sound engineer should know the difference between sound quality and subjective preference of different sounds. Distortion, noise, compression, limitation, altering of frequency response by equalizer, phasing, modulating, pitch shifting and every kind of manipulation to the sound is artistic decision to make a better mix. Every manipulation of sound makes a difference to the original in most cases by degrading the quality. I have heard many good sounds that are completely distorted and noisy. I like metal music and distortion, overdrive and noise is part of this sound. Audio quality is very different in comparison to recording of symphonic orchestra or acoustic duo.

      I have found that summing signals from digital converter on an analog mixing board will give you more headroom to go further. Headroom is the point where your signal stays clean without distorting. That is what it is. I will not go in to details. You can read about it in the books or internet.

      You get more headroom to work on and with analog mixer it is possible to push audio more into saturation by sacrificing audio quality and increasing noise in the process. Some of the mixers do this more delicately, some of them sound horrible. Digital sound limits you to the volume level of 0dPFS (threshold of clipping).
      In the end everyone listens to music in digital format, so you will convert back to digital anyway. Headroom is not really something to worry about as long as you know what it means and how to work with it.

      The best mastering engineers often use analog gear. This is their work and they should have the best possible gear and software. Most importantly the person needs to have a good ear and professional touch to mastering. Long time ago mastering was only a quality checking process before cutting the sound onto a vinyl. Nowadays it is more than that, but basically mastering engineer’s job is to be a person who checks for quality of the sound, loudness and overall pleasantness of listening experience before mass production. Making some kind of analog magic and luxury ear candy is mostly just marketing. If you put shitty music through 5000€ compressor, you get shitty music compressed with 5000€ compressor. If listening to music encoded to mp3 with 1€ earphones you really can’t tell if the music is mixed and mastered with digital or analog.

      When you listen to music, you are listening to digital music most of the time, which is converted to analog and then converted to air pressure changes by a moving cone in your speaker.
      Digital doesn’t sound thin, overly bright or bad. It has no “sound”. It is just a container of information.

      Most people can’t even concentrate on bassline and vocal in the same time, so I don’t worry about them hearing difference about digital and analog processing.

      The music business at this point is in a downfall financially. More and more music is done by producers only with a laptop in the bedroom. More music is done without real instruments and live players. More guitarists are using digital modelling amplifiers, not tube amplifiers. Musicians are using simpler compositions, arrangements and lyrics in popular music.

      To next to “a next level” with audio engineering and production, education and learning is the most important. Knowledge about sound quality, electronics, digital and analog signals, acoustics, speaker systems, processing techniques and everything sound related is most important.

      I would recommend for reading a few publications:
      Technical details about (old) digital mix processing in Pro Tools HD: http://akmedia.digidesign.com/support/docs/48_Bit_Mixer_26688.pdf
      About digital audio by mastering engineer Bob Katz: http://www.digido.com/articles-and-demos12/13-bob-katz/16-dither.html
      The Audio Expert. Everything You Need to Know about Audio. Book by Ethan Winer.
      Guide to Mixing by Nick Thomas: https://archive.org/details/GuideToMixing

      And listening to people who know what they talk about:
      Dave Hill talks about analog and digital, and analog emulating digital: https://www.youtube.com/watch?v=SyqPZcFRkRY
      George Massenburg talks many wise words about mixing: https://www.youtube.com/watch?v=YBoZl2ZppoQ

      The subject gets lot more complicated the more you know about it.

      Before making a statement like “analog is better than digital”, everyone should do the research, educate themselves and understand what is digital and analog audio.
      I highly recommend knowledge and understanding over myths and misconceptions.

      Professional audio engineer can create good sounding mixes in analog or digital or combination of both worlds. A computer, well-coded software, a good interface and quality monitoring in a balanced acoustic space is enough for making amazingly good sounding music.

      All the best,
      – JMK

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