Dok's guide to monitor placement in your home recording studio NOW W/Pt. 2: SUBWOOFERS

[Dok]

And one last real-world example before I disappear back into the bushes, using actual examples from the last time I set up my room in my former house - including a conversation with friend of mine who is an acoustic designer for a global architectural firm - some of this stuff is counterintuitive even for professionals like him so that's why you still always have to measure, move, measure, move, repeat. Every room is different.

First, I put my two subs where the Room EQ Wizard room sim predicted the most optimal positioning, but I still had a huge peak around 170hz, and a bunch of really unfortunate decay around 40Hz and lower.



So then I realized that this closet in the rear of the room was still part of the room acoustically speaking and instead of trying to eliminate it from the system maybe I needed to try to utilize it instead, so I put my second sub inside the closet but facing out toward the room.



That helped with my initial peak at 170Hz but created another one, which was a BIG null around 72hz. What to do? I had four different directions the second sub could face plus polarity switch in each direction, which meant 8 different possibilities just for that one position for the second subwoofer. Measure, repeat, measure, repeat.



Voila! You can see that not only did it fill out that 72hz null nicely, it cleaned up some resonance/decay between 30-45hz and moved the bulk of it to below 40hz, which is good enough for my purposes. As you can see there was still work to be done above 200hz, which is where broadband acoustic treatment starts to come into play, but I was within +/- 2.5dB or so for 200hz and below, which is pretty good for an idiot like myself in a bedroom.

[Dok]

Okay okay one last thing, Musician's Friend is running their Stupid Deal on some nice fillable wood full-height monitor stands TODAY for $69. Get those speakers de-coupled from your desk!

https://www.musiciansfriend.com/accesso ... 5000001000

[marqueemoon]

I’m still working on digesting the subwoofer info.

In researching this general topic I found this, which some might find helpful. It ignores ceiling height though, which is an important factor in room modes from what little I understand?

http://noaudiophile.com/speakercalc/

In my case the placement it recommends does seem to square with being clear of the worst of the room mode problems. I tries both the main wall as the “main wall” and speakers on the short side is by far the most practical for my space (specifically Real Trap 38% Option 1).

I’m still going to have to make a bit of of a case with the family on the placement. “I need to set up here because physics”.

The doorway is on one side of the short wall, so If I stick with this placement it may also impact what I decide to spend if I update my monitors as chances of someone walking into one seem high. It would be idiotic to buy fancier monitors and let wanting to protect them dictate where they go though.

[Dok]

I’m still working on digesting the subwoofer info.

In researching this general topic I found this, which some might find helpful. It ignores ceiling height though, which is an important factor in room modes from what little I understand?

http://noaudiophile.com/speakercalc/

The truth is there's not much you can do about ceiling height. Unfortunately, standard ceiling height is 8 feet and standard ear/tweeter height is about 4 feet, which almost always places it exactly halfway in the middle of a big ass null. You can definitely mitigate some of that with a ceiling cloud of absorption and a fluffy rug.

I started with that same RealTraps 38% placement years ago when I embarked on this journey and it did me no favors - each room is different so your mileage may vary with a formula like that, but there's nothing wrong with trying it out as a starting point and then evaluating your results. It also doesn't seem to take into account room width because it lets you decide how far apart your speakers are. I'd really recommend plugging your dimensions into the axial mode calculator and giving it a go - you can at least then put your speakers and listening position into the Room EQ Wizard simulator and then you can play with sub placement. But whatever you do, this is all about finding your way to the least compromised positioning in a system that usually requires a ton of compromises!

Or if you want to post your room dimensions we could work through it here as another example for other readers of this thread, which might be helpful!

[Dok]

Happy to help! Honestly it came out of a) going fucking crazy for YEARS trying to get my mixes to translate (honestly, I wouldn't wish that on anyone, please learn from my pain) and b) the near constant amount of threads I see on audio and music forums containing various amounts of misinformation and conventional wisdom about speaker placement and subwoofers - and people spending WAY too much money on more and more expensive monitors that would never perform optimally if not positioned correctly. This way I can just point back to this thread instead of having to try to condense it into one post. Just last week I was arguing on the TapeOp forum with a mastering engineer who, after I shared a bunch of this information, still said something to the effect of "I just don't believe that a subwoofer can do this without overloading the room with low-end frequencies, and the only possible solution can be to just keep putting in more bass traps." But as I said on that forum, It absolutely feels counterintuitive but you don't have to "get it" for it to be true. Anybody can test it, anybody can measure the results and see for themselves. It works and is reproducible in every single room I've ever tried it in. And it sure beats fumbling around in the dark and trying to guess where to put more expensive absorption than may be necessary while pulling your hair out wondering why your low end never seems to translate.

Reviving this thread to show a recent example of this bias in action. If you're not familiar with Eric Valentine, he's one of the best engineers/producers around (seriously, his mixes are WILD), he's seriously gotta be one of the great contemporary minds as an audio and electrical engineer (also the guy behind Undertone Audio) and he has an incredible YouTube series called Making Records with Eric Valentine. I have learned so much from watching his videos. Over the past few years he's documented a complete bespoke studio build to all of his exact specifications in this amazing farm in Vermont, and for someone like me who has to live vicariously through someone else with the wherewithal to execute an endeavor like this it's been SO FUN to watch his progress over the past few years. So just keep in mind this is a guy who has forgotten more about audio and mixing and engineering than most of us will ever have a chance to even sniff, and that especially goes for me, who am an idiot.

Here are two videos, both really long and involved, but they are perfect examples of what ends up happening when you try to do this without subwoofers. And not just you, basically the smartest guy in the world at this:

https://www.youtube.com/watch?v=JS09lUjzD-E

And you can start here about 50 minutes in: https://www.youtube.com/watch?v=7N_-paQAuWM

Just check out how much he ends up needing to over-engineer the acoustic treatment in his control room because he’s completely omitting subwoofers. He never says why he doesn't want/use them, but it is striking to me that they are never even considered or mentioned, not once, and it shows in his results. He finally ends up with decent outcomes considering he seems to have every square inch covered with acoustic treatment (and then uses DSP), but the reason is not because he applied any mathematical or physical understanding to this other than the initial room dimensions, it is because he underwent a massive, maddening, completely inordinate and frankly unaffordable amount of trial and error, as will anyone who is not taking a systematic and data-driven approach to this involving subwoofers.

You can watch the next several videos and watch him drive himself (and yourself) crazy while he fumbles his way through tons of money and time not to use a subwoofer or two.

[DeathJag]

Man this thread may have given me "too much info!" Kidding of course. I say that because it seems no one else has been hipped to it, and it ends up being a whole challenge instead of a discussion. I'm just trying to share the facts, and I've sent a few folks to this thread, but they see it as some kind of outlaw theory. I'm not a studio person at all, and I suck as mixing and mastering, but the way you laid out the facts was utterly convincing. I don't get why some people aren't open to new information.

[Embenny]

Man this thread may have given me "too much info!" Kidding of course. I say that because it seems no one else has been hipped to it, and it ends up being a whole challenge instead of a discussion. I'm just trying to share the facts, and I've sent a few folks to this thread, but they see it as some kind of outlaw theory. I'm not a studio person at all, and I suck as mixing and mastering, but the way you laid out the facts was utterly convincing. I don't get why some people aren't open to new information.

Most reality-based info about acoustics is wildly unpopular, because it tells people that the things they want to do (cram monitors up against a wall or in a corner, sit them on a desk, use a tiny room, etc) are unfixably bad ideas, whereas what they want to hear is that putting up eight 2" thick panels on the walls will fix everything.

And don't get me started on audiophiles, who are so busy buying $1k cables and magic beans for their $20k systems that they can't be bothered to rearrange their living rooms or put up proper acoustic treatment.

[Dok]

I think also that acoustics are really another whole field of study, not technically but practically entirely separate from music or mixing - these are art forms, after all, but instead of a guitar being your instrument it's instead an entire system of physical (and virtual) objects that each have an impact on one another. How can you accurately model that or even explain it? You really can't model anybody else's playback system. Hell, everybody's ears are different, too. Even in this abridged, dumbed down version it's pages of concepts that need to be understood before you can start to apply them, and unless you've already gone through all that trial and error a few times you're probably not all that inspired to tackle it.

And I think the anti-subwoofer crowd could have some sort of purist mentality, too, either in a "back in my day we didn't need no such thing" or "I'm not even making bass-heavy music that needs subwoofers", which is where I came from. But I think a lightbulb goes off when you understand that a subwoofer's function is not to enhance bass frequencies already present but merely to restore the ones that are missing from your entire acoustic system (which is the room you're in, your speakers, and your ears). And you really can't argue with people who have been doing things a certain way for decades most of the time either.

I still love to go shopping for more expensive monitors even though the ones I have are not the limiting factor keeping me from becoming the next Eric Valentine. But that thread is longer still.

[marqueemoon]

Happy to help! Honestly it came out of a) going fucking crazy for YEARS trying to get my mixes to translate (honestly, I wouldn't wish that on anyone, please learn from my pain) and b) the near constant amount of threads I see on audio and music forums containing various amounts of misinformation and conventional wisdom about speaker placement and subwoofers - and people spending WAY too much money on more and more expensive monitors that would never perform optimally if not positioned correctly. This way I can just point back to this thread instead of having to try to condense it into one post. Just last week I was arguing on the TapeOp forum with a mastering engineer who, after I shared a bunch of this information, still said something to the effect of "I just don't believe that a subwoofer can do this without overloading the room with low-end frequencies, and the only possible solution can be to just keep putting in more bass traps." But as I said on that forum, It absolutely feels counterintuitive but you don't have to "get it" for it to be true. Anybody can test it, anybody can measure the results and see for themselves. It works and is reproducible in every single room I've ever tried it in. And it sure beats fumbling around in the dark and trying to guess where to put more expensive absorption than may be necessary while pulling your hair out wondering why your low end never seems to translate.

Reviving this thread to show a recent example of this bias in action. If you're not familiar with Eric Valentine, he's one of the best engineers/producers around (seriously, his mixes are WILD), he's seriously gotta be one of the great contemporary minds as an audio and electrical engineer (also the guy behind Undertone Audio) and he has an incredible YouTube series called Making Records with Eric Valentine. I have learned so much from watching his videos. Over the past few years he's documented a complete bespoke studio build to all of his exact specifications in this amazing farm in Vermont, and for someone like me who has to live vicariously through someone else with the wherewithal to execute an endeavor like this it's been SO FUN to watch his progress over the past few years. So just keep in mind this is a guy who has forgotten more about audio and mixing and engineering than most of us will ever have a chance to even sniff, and that especially goes for me, who am an idiot.

Here are two videos, both really long and involved, but they are perfect examples of what ends up happening when you try to do this without subwoofers. And not just you, basically the smartest guy in the world at this:

https://www.youtube.com/watch?v=JS09lUjzD-E

And you can start here about 50 minutes in: https://www.youtube.com/watch?v=7N_-paQAuWM

Just check out how much he ends up needing to over-engineer the acoustic treatment in his control room because he’s completely omitting subwoofers. He never says why he doesn't want/use them, but it is striking to me that they are never even considered or mentioned, not once, and it shows in his results. He finally ends up with decent outcomes considering he seems to have every square inch covered with acoustic treatment (and then uses DSP), but the reason is not because he applied any mathematical or physical understanding to this other than the initial room dimensions, it is because he underwent a massive, maddening, completely inordinate and frankly unaffordable amount of trial and error, as will anyone who is not taking a systematic and data-driven approach to this involving subwoofers.

You can watch the next several videos and watch him drive himself (and yourself) crazy while he fumbles his way through tons of money and time not to use a subwoofer or two.

Yikes. As obsessive a person as I am (I watched most of that), this seems like hell to me.

The concept of the panels is interesting though.

[GreenKnee]

what they want to hear is that putting up eight 2" thick panels on the walls will fix everything.

Every DIY studio I've ever been in...

[Dok]

I guess I should make it clear that you also will still need broadband absorption, especially at first reflection points and the front and rear walls, as well as above you on the ceiling, but as you can see in those video examples, no reasonable amount of it can substitute for poor placement and lack of subwoofer(s). I am not saying that you don't need acoustic panels! And there are lots of forum posts out there all about that topic.

[tlindaas]

I wonder if AVAAs will work well in the same room as subwoofers. In theory, AVAAs are simply flexible-frequency pressure traps, which should work fine in a room with subwoofers. But I can't help to wonder if regular subwoofers and AVAAs (which are technically subwoofers in reverse) will manage to cooperate, or if they would end up fighting each other.

https://www.psiaudio.swiss/avaa-c20-active-bass-trap/

[Dok]

I wonder if AVAAs will work well in the same room as subwoofers. In theory, AVAAs are simply flexible-frequency pressure traps, which should work fine in a room with subwoofers. But I can't help to wonder if regular subwoofers and AVAAs (which are technically subwoofers in reverse) will manage to cooperate, or if they would end up fighting each other.

https://www.psiaudio.swiss/avaa-c20-active-bass-trap/

Are you affiliated with this website or product? Those are an interesting device but probably far beyond the scope of the info I'm trying to share, and could do more damage than good unless you have a very specific problem you're trying to solve with them. And while I'm not an acoustician, "technically subwoofers in reverse" does not seem like an accurate description nor a concept that I'm sure I fully understand at this moment.

[øøøøøøø]

They are just active traps

They do work and “subwoofers in reverse” is a fair layperson’s description of what they do. In fact they make use of destructive interference to counteract existing energy at very low frequencies (they “push” when the room is trying to “pull”)

But they are expensive

I asked an acoustician friend about this specific model recently

His remark was that they work well; very good for temporary installations

But if building a permanent space, there are more cost-efficient means of getting similar levels of efficacy

I’ve mostly stayed out of this thread bc my approach to acoustics in a working or listening space diverges quite a bit from what has been presented here overall

In the coming months I’ll be building out a new space (my sixth buildout) and if there is any interest it might be nice to document my approach (but I would do so in another thread)

[tlindaas]

I borrowed the "subwoofers in reverse" shorthand-explanation from this Sound On Sound review: https://www.soundonsound.com/reviews/psi-audio-avaa-c20

The AVAA subwoofer is said to work "in reverse" because it "[...] generates a sound wave with an inverted polarity but the same level as the naturally reflected sound wave, and it is phased (or timed) precisely such that the two cancel each other out more or less completely."

This sounds exactly like what noise-cancelling headphones do, to me at least. But for some reason the company refuses to make that comparison. "There is neither anti-sound emission nor noise cancelling nor a “reversed” subwoofer – just highly efficient absorption."
https://www.psiaudio.swiss/psi-audio-av ... echnology/

Anyway, the practical effect in the mix posistion is a flatter bass response but also less bass. That's why I figured it could be combined with subwoofers. The company (PSI) actually sells subwoofers themselves. I think I will email them and ask them how they combine..

I am not affiliated with PSI.