Ok, flame on if you must. But here's the deal...

After listening to numerous audio samples of ITB and OTB summed mixes, and several different boxes, I am just not hearing any difference. I've listened in two different control rooms on Genelecs and Haflers and sorry to say any noticeable difference is just not there. Wider mix? More Spacial? More headroom? Really? Maybe I need a scope of some sort to discern the added magic these boxes bring to a mix, but I'm not in the habit of scoping my mixes and go with what my ears tell me.

I realize there are as many supporters of this mixing approach as there are opponents, but... and this is my one disclaimer to this argument:
other than using a sound coloring summing box like a Neve, BAE, or similar which has more features than just simple routing, (and there are those who say that the feature packed summing mixers aren't true summing mixers to begin with,) the routing out of Pro Tools thru a box of resistors and back into Pro Tools just doesn't add anything that I can hear.

Ok, bring it on. I'm ready.

ITB summing has made leaps since the introduction of summing boxes. I dont think many would argue that a summing box is needed to retain the integrity of a mix on mix-down these days.

I do think a lot of people still enjoy summing boxes for the other colouring and workflow reason you mention, though.

Gustav

I think it depends on the box. I was happy with my api setup, the main advantage being able put outboard on stereo groups + master buss in analog and not have more ad and d/a

Well, that's just good news right? You can happily stay in the box and save money you might have spent on a summing box.

I agree. I have a Symphony + Dbox setup and I stopped going thru the hassle of summing because it just doesn't add enough for me to go thru that extra step. I think you hit it when you said you need a summing box with some color to really notice a difference, otherwise its mundane.

Are you listening to other people's work or are you trying this stuff yourself, in your room, with your ears and workflow?

I you are doing it correctly, there will not be a difference.

If you run a hot mix out it and the dac isn't neutral sounding, then there will difference.

One of these days I want to get one, or make one of those multi-chanel tube DAC just to add a different character to one stem in a mix.

I have the Dangerous 2-busLT. I am pretty new to it, but there is no question to me, or the people who have been with me that it makes a big difference.

I have yet to have a finished mix mastered and released, so my opinion might change, but right now, I think it is one of my best choices.

I recently changed from RME FF800 to Aurora for conversion. Right after that I started working a bit in 96K. Neither of those changes had near the impact that adding the Dangerous box did.

I never really just A/Bed anything. I pulled up a song and set it up and started mixing into the 2-bus and immediately noticed clearer low end and less fighting for frequencies. Since then noticed clarity and less fighting while mixing. I am finding that I make decisions faster.

Tough to describe, but my suggest is to pick up a used Dangerous box and live with it for a while. They hold value incredibly well.

Again, don't mean to be a cheerleader, just sharing my experience.

Years doing ITB mixing , Set up a SSL sigma plus a bunch of 2 Bus comps . what I find is I am able to get the guitars up a bit louder without taking over the Mono stuff , snare and Kick . It is hard to describe , So I end up mixing a bit different with a summer . So for that alone I happy .

I have the dangerous DBox which I use on the regular basis with summing. I find it makes the mix a little bit less cluttered then when I sum ITB. The difference between the two is only about 7 to 8%

The sound doesn't change but the mix is just a little more open. Plus when you are mixing and you're running or your mix into the Dbox it doea provide more headroom. You don't have to bring down your faders because your main output is getting into the red.

Analogue summing is not something you can really hear in an A/B example. Its more about how the mixer sounds and behaves during the actual mixing process. The way the mixer interacts with your fader moves and how the master bus distorts based on your inputs are really where the difference is made. The summing console "bends" and gives you different sounds based on what feed into it.

Another analogy would be sex. You can read about it, listen to it, ask your friends about it, but you won't truly understand whats its like until you do the deed. : )

Also analogue summing works at its maximum effect with most number of channels. 8-16 channels give the user a taste, but in the 32+ area it works even better. I use 52 channels.

Strange. I built a passive summing box that's basically just a bunch of resistors and jacks and I can clearly hear the difference. I even did an A/B blind comparison and got it right every time after I heard both files. The give away for me is the separation between each of the instruments. But I also noticed a higher noise floor and slightly less high end, probably due to my Audient Mico which I used for make up gain and conversion. It's not the highest quality piece, but it's not bad.

Now I won't say the difference was night and day, nor would I have any issues with using ITB summing. You can get great results either way. But even on my Tannoy Reveals in my poorly treated bedroom the difference in instrument separation was pretty apparent.

On a semi related note, I need to get a transparent compressor to tame the peaks a hair to bring the level up OTB because it did seem to be a bit more dynamic. You couldn't hear the increase in dynamics so much, but I did have to lower the input volume a good bit to keep it from clipping. Hence the increased noise floor.

you're doing something wrong. playback any mix going out 2 channels, then move any single instrument out of the mix onto it's own track. can you hear it better? answer: yes.

I have found the main benefit of a summing box is that you can feed its inputs hot from your DAW. If you have hot levels on your tracks in the box things will quickly go into the red on the main outputs of your DAW and be accompanied by nasty clipping. There are summing boxes out there with colour and boxes without colour. I personally prefer a box without colour. What I like about my Dangerous 2 Bus is that I can have a + 6db boost on the inputs which comes in very handy at times.

The Dangerous D-Box has a very very clean summing section. I have found it hard to notice a difference using the summing on the D-box compared to a ITB mix.
The thing i did notice about the D-Box is that the stereo image is a bit wider.
May i suggest trying a Passive summing mixer? You can get whatever color you need depending on the preamps you decide on.
At the end of the day it is all about your workflow though.

This! Hard to describe but just better sounding mixes.
You should try a Sigma, totally different universe compared to a passive box.

Never done A/B because I mix differently ITB than OTB. I like using mt OTB16 because I can put my SB4000 on my drum stems, BAC 500 on bass and One LA and E27 on my vocal. Then I have my MAAG's and Obsidian on the 2 buss. Not sure I could get this sound from ITB.

In my my experience I've heard no difference with any of the clean summing mixers I tried (Dbox, Folcrom with a Grace preamp, Audient) and some (nice) coloration with the Neve 8816, particularly when pushed. However even on the 8816 feeding a stereo signal or 8 stereo stems seemed to make no difference, so the pleasant coloration probably comes from just passing the signal through the transformers. For me using one of these boxes only makes sense when your workflow involves making a lot of use of the inserts to patch in hardware.

If you mix to the vision that is in your head, then chances are it will sound pretty close no matter how you get there. For ME, my summing setup helps me get there faster. My summing amp does some of the work for me and helps facilitate a fast workflow. Picking a summing amp that has flavor and separation that you prefer in your mixes can help you achieve your visions faster.

At the university where i teach, we have an SSL Duality SE, PT HDX and a bunch of really expensive outboard.

Because I know how to mix ITB, I prefer it that way, I can hear absolutely no difference at all summing through the SSL.

The SSL is a wonderful front end (particularly when controlling PT), we've got 48 inputs - which is really useful for the school's plethora of recording options.

A well designed board should be clean, not "colored", so I've never understood it when people say "I like the color" ??? The SSL has no color. There should also be no reason at all for "increased clarity, separation and a 3d effect", nor should analog summing provide one with more "accurate panning" (what could be more accurate than digital?).

Still, people continue to claim huge gains with analog summing, it baffles me.

I definitely prefer analog summing, but a big part of it comes down to my mix workflow, which involves a buncha hardware and parallel processing. Delay compensation and hw inserts just don't quite do the trick, unfortunately.

But even without the outboard gear, I still prefer the sound of OTB summing. Last I checked, the improvement was not particularly subtle. Though to be fair, it's been some years (and PT versions!) since I did a direct comparison of ITB vs OTB summing. Maybe it's time for another shootout.

As a few have already asked, are you merely playing a 2trk mix of someone else's finished work through your A/B comparison, or are you playing your raw multitrack mix through it's separated outputs compared to completely mixing ITB? The analog summing of 20+ channels is where the OTB argument poses a formidable argument. Also, don't think of OTB summing as something that will magically make your mixes better. Skill certainly applies, whether it's ITB or OTB. Also, a lot of OTB magic happens with small amounts of mojo skillfully applied with your keen experience in using various OTB methods, "tricks", gear, etc....
But, it truly all comes down to what works for you. If you can't hear a reason to drop a bunch of cash on Outboard Summing, then don't! No need to waste money on gear that doesn't get you closer to where you want to be!
Good luck!
JJ

Pretty much sums it up, either you find it valueable or you don't
Not need to debate about how define value.

If you're taking a mix you did in the box and then just running it through the summing amp you won't notice much of a difference. I did that when I first bought mine and thought I had been totally ripped off. I noticed the difference when I started mixing THROUGH the summing amp. I started approaching my mixes differently because I HEARD things differently. I could hear the stereo image better, I could hear my reverb and delay tails better, and I could hear separation between my submixes (drums, bass, instruments, BG Vocals, Lead Vocals, Effects). It isn't something you add into your mixing chain that's going to instantly make your mixes better.

I gotta say that ambivalent threads like this made me pass on summing for years. why try if some can't hear the difference and it costs thousands $$? well i wish to god i had those years back! let this be a lesson for inquiring minds. you can sit around a balance everything thru 1 digital buss like a tightrope, or simply allow your mix to explode by allowing your channels to breathe. It's your choice! seriously -- the best audio companies don't make multi-thousand $$ mixers just to exercise factories.

I add a d-box to my rig few weeks ago.. i'm still amazed!! more low end, more space... suddenly some frequency appears... I love it!

But this is Gearslutz, there is "politically correct concensus" here. That's "buy Slate or Nebula" and you don't need anything else. the forums are full of jealous people, having no hindsight, doing nothing else than preach VST's and argue with the more discerned who appreciate hardware. Because if they can't have it, they will for sure do their best to squeeze the fun out for everyone else. Never ask for opinions on GS. As every debate needs to end with that if outboard is chosen, it is certainly for "workflow" and not for "sound quality"
So miserable heh
So yes, analogue summing sounds better an YES inserting analogue outboard in your analogue signal path will take things to a whole new level. There! I've said it heh
Flame on

I used different methods over the years. One was using the DAW mixer, but out to stereo to parallel process (eq-comp+eq-comp into limiter), then to another DAW at twice the sampling rate.

OTB is nice flow if you are doing stuff like external ducking or even external side chaining eq/compression from several channels to two, or one.

I would even argue that if you sum through a pretty linear external summer, the process in itself does more harm than good because all it does is to mess up the balance of the time dimension even more (due to the additional DA-AD route, if you have outboard gear though you can achieve a more balanced time dimension taking that additional DA-AD route) with little to compensate for it. But if you are summing due to the impacts the nonlinear characters have on your mixing and mastering and you select the summer(s) accordingly, then even with the added distortion in the time dimension you can end up with better results than not having that. I sum primarily through a Neve and I prefer the sound of that. In this way I can also bring in other outboard gear (e.g., compressors/limiters in mastering) on a more narrow scope than the stereo mix, this can sound very good because some outboard limiters can input high voltages, so I can basically indirectly get higher quality limiting from it on various scopes (before and after the summed signal), kind of what makes a mix "pop". What converter are you using when you incorporate the external summer? The quality of that will also be a factor in this.

These conversations are always so clumsy because summing get's so mixed up with workflow, latency issues, hardware integration, observer bias and a healthy dose of the ikea effect (for either camp)...

One thing I can say without a doubt is I've heard abject crap mixes and killer mixes from both. I do seem to come across more people who are precious about their work when it's through some OTB summing setup. Meaning objectivity clearly left their life a long time ago...

Horses for courses but I tend to believe that nothing OTB really adds fidelity as much as it can pleasantly take some away. The slight audio version of 'rose colored glasses' makes us less nitpicky about timing and pitch corrections etc.

BUT- I also tend to think that unlike post guys, the music world has been very slow to embrace the potential hi-fi aesthetic that digital offers us. Mainly because I think you have to fully embrace it...track with no compression, 20dB of overhead, put those tube mics away for a minute and see how this really sounds. This will make you work differently too!

To that end I think that if you are going for a modern clear sound like sylvan esso to frank ocean etc then you maybe you don't want those rose colored glasses. OTOH for say spoon, then yeah, probably you do.