Homestudio flush mount speakers

[DYSTONIA]

Hi there,

Disclaimer (I'll update with more photo's and details but I've to get some wood. So that's why I post a quick message right now so I don't forget this forum).

I'm building a studio at home. Soundproofing is going good so far. The only 'problem' im worrying about is my frontwall construction. Here is my idea: I want to build my speakers in the wall but with the subwoofer above it. Why? Somebody told me that it doesn't matter where your subs are because the're non directional.

In the attachment you see a few photo's and the new one I made 5 minutes ago. The measurements are made without the desk. I know a big desk can give some problems but I will deal with that.

So long story short: I will flush mount my setup. But what is the best thing to do? The photo with the black 'boxes' are fully filled with sand and about 100kgs. I made those 4 years ago and now cutted them and are exactly at air height. Contacted KALI if I can use this 3 way speakers on the side. They told me that it's even better if I want a wider stereo field. So build in the subs aswel to get 'one big speaker' or just build in the KALI's (5 inch 3 way model) and place the subs later on. They're separately connected to my AD/DA Soundcard so left is 100% left and vie versa.

I hope I explaining it well, because Im a little bit of a rookie about acoustics and love to give as much info as possible.

Thanks!

[Soundman2020]

Hi there DYSTONIA, and Welcome to the forum!

Congratulations on your "in progress" control room! You'll find a lot of help about your questions here on the forum, and several threads by people who have built their own rooms similar to yours... or are in the process of doing that.

First, mounting your sub above the mains isn't a problem, if that's what you want to do. As you have already learned, low frequency sound isn't very 'directional', in the sense that it's hard for our ears and brains to identify exactly which direction the sound is coming from.

However, that doesn't man you can just put a sub anywhere! There will always be interaction between the sub itself, and the room it is in, and putting your sub (or subs!) in the wrong place can have a detrimental effect on the overall room response. By the same token, placing your subs carefully to work together with the room can have very substantial benefits.

For example, if you place the sub on the center-line of the room (spaced the same distance from the left and right side walls), that can create interference patterns that result in "lobing" (regions of increased or decreased bass intensity), and the interaction between the sub, the mains, and the room can do the same. You can end up with some areas in the room sounding "dead" in the bass areas, while other areas boom and resonate.

Small rooms will always have modal problems. Here's an article I wrote about that a while ago, that you might find useful: Modes, Room Ratios, and Schroeder Basically, your room will reverberate at certain very specific frequencies, and will also have "nulls" at other very specific frequencies, and those frequencies are related to the dimensions of the room. If your sub happens to be in a null for one of those frequencies, then that frequency simply won't be present in the room, because the sub will be unable to propagate that frequency well. On the other hand, if your sub happens to be located in a modal peak, then that specific frequency will ring out loud and long, since the sub will easily trigger the mode.

You can see some of the issues in the REW graph you posted: You have large bass peaks at around 40 and 70 Hz, and a major deep null at around 52 Hz. Those are very probably associated with your room dimensions. Placing your sub in the wrong location could make those even worse. Placing it in the right location can improve that.

So, it is important to place your sub correctly, in a location that does not cause it to fight with the room acoustics, and rather uses the sub to help deal with modal issues of the room. There are methods for locating the best position for your sub. One simple one is to just do things "backwards", and use your ears (or REW). Basically, set up the sub exactly where your head will be while mixing (on a tall stand), then go stand / sit / crawl with your head where you think you'd like to place your sub, and listen carefully to "frequency sweeps" that cover the bass region. Move your head around until you find the "smoothest" spot, where most bass frequencies sound roughly the same level, with minimal "ringing" and reverberance. That will likely be the best spot for your sub. You can be more accurate with this procedure if you use REW, and move the mic around (instead of your head). Take many readings with the mic in many positions; use a measured "grid" of mic locations, do a test with the mic in each of those grid points, then compare the results. Choose the spot that has the smoothest overall response. That's where you should put your speaker.

However, for this technique to work properly, the room first needs to be fairly well treated with acoustic treatment. It doesn't need to be fully completed, but at least the bass trapping should be in place.

If you place your sub properly in the best location, that can go a long way to making your room sound smooth and getting your mixes to translate well.

I'll get back to you with more details on your actual question (about flush-mounting your mains) in a while.


- Stuart -

[Soundman2020]

Forgot to mention: There is even one method of placing several subs in the room, at carefully selected locations, then "tuning" the subs to actively cancel out some modal issues. This is sometimes referred to as a "plane wave bass array", and can have very significant results, when done properly, I' have designed a few rooms like that. Here's the results from one of those rooms: A properly treated and tuned control room: S3P - And the full acoustic response report on that room, in detail: Studio 3 - Final Acoustic Test Report


- Stuart -

[DYSTONIA]

Wauw! Thanks for this information! I'm happy to see that sub placement (height) doesn't make that much sense. So I did read everything but it is a lot of information. For now I've nothing done with acoustic treatment because the Blackwall is not even 'finished'. Is it a good idea to send some pictures how the room is now because I was hoping to do the frontwall and angle of the 'main' system at the system time.

Whatever, I'm rambling. I will take some pictures right now. And give the exact sizes.

Sorry for my bad English or whatever but I'm a little bit insecure about placing mainfield/subs. I did setup the whole 'thing' and found a spot where (for me) the bass response was the most accurate. Didn't now that the 30 degree angle is really depending on the room model, as you noticed.

Long story short. I'll clean the room real quick and post some photo's!

[DYSTONIA]

So here are the pictures. I've no space left in my house but this room is now almost clear. I don't know if the pictures are random uploaded. But I think it's easy to figure out. I also uploaded a file with the dimensions before I started building. Soundproofing is not the main thing. But for now nothing is touching the wall and the floor is floating. Besides that. Just put down the speakers and subs because they were standing in the bathroom lol. And it's a really good sound system while building haha.

I also have to figure out to make the door frame and the ceiling is also not done either. But that is not that difficult. The number one thing for me is that I have it soundproofed between 80 tot 100% and the acoustics is more important. So the room size with the current building state is 318mm from the front to the Blackwall (inner size); from the left to the right wall; 243mm (inner size); and the ceiling to the floor is 254mm (from floor to concrete) Because the Blackwall is not symmetrical I decide to flush mount the speakers whatever it takes. Im running out of budget and time.

EDIT: Ow did take the photo's vertical because im using an old iPhone when im building and the camera doesn't have a wide angle. One thing to mention. The floor where the speakers are standing right now is double layered. I was thinking about to do the whole floor, but don't have a car at the moment so maybe later on but also keep in mind that every layer is taking space in the height of course. Doesn't make sense I think?

[Soundman2020]

Source of the post EDIT: Ow did take the photo's vertical because im using an old iPhone when im building and the camera doesn't have a wide angle. One thing to mention. The floor where the speakers are standing right now is double layered. I was thinking about to do the whole floor, but don't have a car at the moment so maybe later on but also keep in mind that every layer is taking space in the height of course. Doesn't make sense I think?

There's a bug in the Forum software that turns some photos "sideways", for unknown reasons, even if you rotate them properly in Photoshop or something similar. I've tried to trace the bug and fix it a few times, but no success so far. So the "sideways photo" probably isn't even your fault!

- Stuart -

[Soundman2020]

Oh, and one thing about your REW graph: The vertical scale that you used is very large, so all the trace is squished up at the top. Try setting the vertical scale in REW to cover the range +30 dB to +110 dB. That will give you a much more realistic view of the actual room response. There's no point in showing anything below 0 dB, and certainly not -140 dB!

- Stuart -

[DYSTONIA]

Source of the post

Source of the post EDIT: Ow did take the photo's vertical because im using an old iPhone when im building and the camera doesn't have a wide angle. One thing to mention. The floor where the speakers are standing right now is double layered. I was thinking about to do the whole floor, but don't have a car at the moment so maybe later on but also keep in mind that every layer is taking space in the height of course. Doesn't make sense I think?

There's a bug in the Forum software that turns some photos "sideways", for unknown reasons, even if you rotate them properly in Photoshop or something similar. I've tried to trace the bug and fix it a few times, but no success so far. So the "sideways photo" probably isn't even your fault!

- Stuart -

Thanks for reply. Just turning my MacBook sideways haha.

Source of the post Oh, and one thing about your REW graph: The vertical scale that you used is very large, so all the trace is squished up at the top. Try setting the vertical scale in REW to cover the range +30 dB to +110 dB. That will give you a much more realistic view of the actual room response. There's no point in showing anything below 0 dB, and certainly not -140 dB!

- Stuart -

Like this?

[DYSTONIA]

Source of the post So, it is important to place your sub correctly, in a location that does not cause it to fight with the room acoustics, and rather uses the sub to help deal with modal issues of the room. There are methods for locating the best position for your sub. One simple one is to just do things "backwards", and use your ears (or REW). Basically, set up the sub exactly where your head will be while mixing (on a tall stand), then go stand / sit / crawl with your head where you think you'd like to place your sub, and listen carefully to "frequency sweeps" that cover the bass region. Move your head around until you find the "smoothest" spot, where most bass frequencies sound roughly the same level, with minimal "ringing" and reverberance. That will likely be the best spot for your sub. You can be more accurate with this procedure if you use REW, and move the mic around (instead of your head). Take many readings with the mic in many positions; use a measured "grid" of mic locations, do a test with the mic in each of those grid points, then compare the results. Choose the spot that has the smoothest overall response. That's where you should put your speaker.

However, for this technique to work properly, the room first needs to be fairly well treated with acoustic treatment. It doesn't need to be fully completed, but at least the bass trapping should be in place.

So if I understand u correctly; I've to finish the room first so I've a the box sealed and then do some acoustic treatment? That's a no go for me because I'm not gonna work with panels etc.. I want the room as death as possible because im used to it and it feel's more like a workplace instead of a living room with some panels on the wall. A good sounding room is amazing. But I wanna close the door and dive deep into Logic without any daylight. I love to work in blue light with a little bit of warmth from another source/lamp and i got some serious amount of LED lights haha.

So maybe it's a dumb question; why doing treatment first and then speaker placement? I know that there some 'standard rules' were to start like the corners, first reflection etc.. But as mentioned before, that's not my goal. That's also the reason why I want to flush/sofitmount the speakers. Not only because it tackle's the symmetrie of my frontwal but also from an ascetic point. You walk into the room and throw everything on with (serious! haha) one switch and USB C cable and get into the flow. That's why I didn't do any cabling yet, it will be under the acoustic treatment which also covers the floor instead of a regular plinth.

But what is the most handy thing to do right now? Putting just the one sub in the room somewhere and move it around the frontwall or setup the whole setup and move/change the triangle to get the best response without any treatment. So then I need to finish the building first. I'm using a calibrated SonarWorks MIC with REW (Soundcard calibrated but doesn't matter I read somewhere).

Sorry for al those questions. But I can build that wall once and the speaker placement is of course. I've seen a few studio's with stereo subs and when I heard it for the first time I knew; oke I need this at home. Also for the headroom and listen solo in the left sub for doing stereo things in the low end for example. Yes, im that producer who smash the master to the maximum without almost no dynamics left in the climax. But that's what Hardstyle/EDM in general needed because otherwise it don't work. But I think you guys already know that haha.

Long story short; what is the best step to go further? Without guessing or making big mistakes. I can build a big bass trap on the Blackwall but I rather spend a few bucks/days extra to get that extra % out of it and learn the room instead of looking at meters constantly. Which I do because I can. But that's relative and for reference. I will mound a monitor/TV on or maybe in the frontwall which is going straight to my Mac to use it as second screen.

[Soundman2020]

Source of the post
Like this?

Yes! Much better. You can see a lot more details like that, and get a more accurate picture of how the room is responding. That's the information you need to figure out the treatment.

- Stuart -

[DYSTONIA]

Quick reply; I've seen and been in a several studio's with multiple subwoofer setup. The first thing I noticed was; people facing the long wall placed their subs outside their main's and people facing the short wall placing their subs straight under/above there main's. Oh and in one studio the sub was exactly in between. But that room was not well treated and the volume always to the max. So is it really room deepened or is it just a simple math to start building around? Because I think every speaker works almost the same way besides custom made speakers. So I've attached three images which explains the placement I describe above.

So I was thinking to do some measurements how the room is now and try everything including the tips u gave me. Just a few measurements and write them down with a photo including the placement details. Or is that just a waste of time?

EDIT: A photo I got from GIK a few month's ago about multiple options.

Quick; is it an idea to start just placing the speakers in the sweetspot which I got right now and starting to treating the backwall with like full absorption like 30/50cm's? Not for the finishing build, just make some samples. I just thinking out loud and constantly run a signal (Logic Tone Generator/REW Live)? Maybe it's cool/try out some different things to achieve the goal without following the standards? Just an idea. So I can see what I do and also listening while placing/moving the speakers around. It's kinda the way I produce haha. Trial & error.

Cheers.

[gullfo]

if you're not soffit mounting the subs, then the best bet is to place the subs slightly off center and pick one to move slightly more towards a side wall. that's a starting point. next up sweeps from each to determine the room response. somewhat different than the normal in the corner to sweep. identify the largest anomalies. then select one, and set the frequency generator to the anomaly and place the subs side by side at the listening position. next up, getting down on all fours and listen for the best response (prefer using something like the REW app to watch via a meter as well as ears). once you have the spot, put one of the subs there. re-sweep. next anomaly, generate, crawl around and monitor. move the second sub there.
repeat as needed to fine tune. with some luck it will go fast unless the room response is really bad.

[DYSTONIA]

Source of the post if you're not soffit mounting the subs, then the best bet is to place the subs slightly off center and pick one to move slightly more towards a side wall. that's a starting point. next up sweeps from each to determine the room response. somewhat different than the normal in the corner to sweep. identify the largest anomalies. then select one, and set the frequency generator to the anomaly and place the subs side by side at the listening position. next up, getting down on all fours and listen for the best response (prefer using something like the REW app to watch via a meter as well as ears). once you have the spot, put one of the subs there. re-sweep. next anomaly, generate, crawl around and monitor. move the second sub there.
repeat as needed to fine tune. with some luck it will go fast unless the room response is really bad.

Thanks for your reply Gulfo, hope you're doing well!

So flush mounting/soffit/whatever only the near fields (KALI 5 sounds amazing BTW)? I see what you trying to explain. I can move the subs while the speakers are in 'perfect' place. Correct? Then I can maybe flip them back to vertical. But KALI told me that the stereo field is much wider/better when using them horizontal. But that's relative I think.

[Soundman2020]

OK, back to "soffit-mounting" (a.k.a "flush mounting").

First, here's something I wrote a long time ago, and have been meaning to update. Most of it is still valid, but as the disclaimer says: "Sometimes you need to bend the rules to make it work for your room".

------------------------------------------
So, soffit-mounting. There's not really a simple way of doing this. Floyd Toole has written a lot about it, and so have others, but all of the "rules" have to be bent a bit to fit the room.

Some of these only apply to speakers on pedestals (not in soffits), other parts are specifically about flush-mounting, but most parts are about both:

Anyway, A few "rules" and guidelines for speakers in general and soffits in particular, in no specific order:

1) The speakers should not go in the corner, nor on the line that divides the corner. In other words, if your walls intersect at 90°, then draw a line out from each corner at 45°, and stay away from that line: don't put your speaker exactly on that line, since it implies that you'll be getting the same artifacts from the side walls as from the front wall. Put your speakers either outside or inside of those lines. More commonly you'll want your speakers "inside" those lines (more towards the center line of the room), unless your room is very narrow, in which case it might be better to have them "outside" the lines (more towards the side walls), and angled in more steeply.

2) The "38% of room depth rule" is not a rule, but it is a useful guideline for a starting point. You'll generally want to have your listening position a bit closer to the front wall than that location, but do be aware that you might be getting into problematic SBIR territory there. (You can treat that, to a certain extent).

3) Keep the mix position away from 25% and 50% of room depth, and try to stay between about 32% and 44%

4) You can angle your speakers differently than the "textbook" 30° angle: Anything in the range 25° to about 35° will work well under most circumstances.

5) Keep the speakers as far apart as possible, while not violating rules 1 and 4.

6) Keep the mix position at a good distance from the speakers, within the range of about 1m to about 5m. Further away is usually better.

7) Don't put the speakers at 25% of the room width: that's a modal null for some frequencies, and a peak for others. Try something more like 28% to 34%. (Note: You can break this rule if you know what you are doing, and want to avoid triggerieng a specific mode: then you CAN put it at 25%... sometimes...)

8 ) Make the front baffle of your soffit as wide and tall as you can, within reason. The width should be at least three times the diameter of your low frequency driver. In other words, if you have a speaker with an 8" woofer, then you want the soffit baffle to be at least 24" (60cm) wide. Wider is better. If you have a three-way speaker where the tweeter is in the middle, between two identical woofers, then the "diameter" is the distance from center to center of the woofers.

9) Do not put your speaker in the middle of the soffit baffle: Offset in both directions. In other words, the distances from the acoustic center of the speaker to each edge of the baffle should be very different, by at least 20%. So for example if your speaker axis is 30cm from one side of the baffle, it should be more than 36cm from the other side, less than 24cm from the bottom edge, and more than 44cm from the top edge. (Rough distances, for illustration only...). Larger differences are generally better. Try to get it at the 2/5th location side-to-side, if possible.

10) Make the baffle as massively heavy as you can, and as immensely rigid as you can.

11) Make the structure inside the soffit (the framing that holds the baffle and speaker in place) as rigid and massive as you can.

12) Mount the speaker inside an enclosure box that is either a very tight fit, in order to keep the speaker rigidly fixed in place, or mount it on suitable resilient mountings, to completely decouple it from the the box. Carefully choose the properties and dimensions of that resilient material, to make sure the speaker is still decoupled down to at least one octave below the speaker's low cut-off frequency. Sorbothane is the best resilient material for this. Do the calculations carefully to get the frequency right, with the correct static displacement.

13) Take into account that speakers need a lot of space behind them for cooling, and a path through the soffit for cooling air to flow. You also need space at hte back for acoustic reasons.

14) Rear-ported speakers need special attention: Do not overload the rear port, acoustically, with an enclosure box that is too small, or un-ventilated, or un-damped. Leave more space at the back of a rear ported speaker, and damp the port itself very lightly.

15) Damp the hell out of the soffit interior! Fill it entirely with suitable damping if you want, except for the cooling path.

There's more to it than that, but it's a start!
-------------------------


Additional to the above:
Regarding the famous "speaker triangle" setup advice, see this: Speaker setup, and the equilateral triangle

Here's some more on the concept behind soffits, also from a few years ago:

-------
Here's how it works technically:

If you have a speaker inside the room (not soffit mounted) then some of the sound is focused like a cone coming straight at the mix position, and some of the sound expands around the speaker in all directions in a sphere shape. The reason for that is very simple: at high frequencies, the wavelengths are short, and the front baffle of the speaker (the front panel) is much larger than the wavelength, so the baffle forces all of the sound to go straight towards you. But at low frequencies, the wavelengths are large, much bigger than the width of the baffle (front face of the speaker), so they "wrap around" the speaker and go backwards behind it as well. This is called the "baffle step" problem, and it happens with ALL speakers, simply because of the way sound works: a sound wave is not affected much by objects that are a lot smaller than the wavelength, but they ARE affected by objects that are a lot larger than the wavelength. So a wave that is 10 feet long is not affected by much at all by a speaker cabinet (or even a desk or chair), but a wave that is 2 inches long is affected by pretty much everything in the room.

That's the basis. ALL speakers suffer from the baffle step problem. The only difference is the frequency where things change over from "focused forwards" to "wrap around". For physically small speakers, that happens well up in the mid range, while for very large speakers it can be down a lot lower. The ONLY factor that influences this, is the size of the front baffle. In the ideal situation, the front baffle would be larger than even the lowest frequency wavelength, so there would not be any problem! In other words, if the baffle could be "infinitely large", then there would be no baffle step problem, and ALL of the sound would be focused directly towards you.

And that's exactly what a soffit does! It emulates an "infinite baffle". It gets rid of this problem by putting a much larger baffle around the speaker, so that the baffle step problem is forced down to a much lower frequency, ideally below the bottom end of the speaker's range. That's why small speakers are really good candidates for soffit mounting, precisely because the "baffle step problem" with a small speaker occurs at a rather high frequency, somewhere in the mid range!

OK, so you might wonder: "What's so bad about having some sound focused forwards and some wrapping around?". Why is that a problem at all?

Actually it is not just one problem, but SEVERAL problems.

First, is power imbalance. Think of this: If ALL of the power put out by the tweeter is heading towards you, but HALF of the power put out by the woofer is NOT heading towards you (it's going the other way: away from you, out to the sides and also backwards, behind the speaker), then you have a power imbalance problem! The highs are 6 dB louder than the lows, because half of the lows wrapped around behind the speaker and went away from you. So there's a major issue here! Therefore, the speaker manufacturer has to pump TWICE as much power into the woofer, so that it puts out the same amount of sound heading YOUR way, as the tweeter, and you hear them at the same level. Have you ever wondered why speakers always have much more powerful amps for the woofers, compared to the tweeters? Part of that is due to this "power imbalance" problem. For a typical studio monitor, the tweeter amp might be 150 watts, but the mid range and woofer amps together are 500 watts! (Just the woofer alone might be 300 watts....).

So there's the first problem: power imbalance. But if you put the speaker in a large soffit, then ALL of the energy is now going straight to you, NONE is going backwards, and you don't need to waste all that power any more. So you can roll-off the bass, because the built-in compensation is not needed any more, and the entire speaker is acting the way it should: sending all of it's power to you.

For this reason, most high-quality studio monitors have a bass roll-off switch on the rear panel, so that you can turn off the compensation if your speaker is flush-mounted, or mounted very close to the front wall.

Next problem: If the speaker is not in a soffit, then think about what happens to that "half of the low end" that went behind the speaker: it hit the front wall, and bounced back! And now it comes towards you again, but out of phase and delayed a little (because it took a little bit of time to reach the front wall and come back again).... This is clearly NOT a good thing! It will interfere with the direct sound, causing phase cancellations, comb filtering, and other nasty problems. This is called the "SBIR problem", where SBIR means "Speaker Boundary Interference Response". It means what it says: the frequency response of the speaker is now all messed up, because the sound that bounced off the "boundary" (front wall) is "interfering" with the sound that came straight out the speaker. Not a good thing at all. It totally screws up the frequency response, and causes a very large dip in the spectrum at a frequency that is related to only one thing: the distance between the speaker and the front wall.

You cannot get rid of SBIR from the front wall by using treatment there, since the frequency is way too low for that. There's basically nothing you can do about it.... except mount your speaker in a soffit! If your speaker is soffit-mounted, then there is no SBIR problem with the front wall! Because NO sound gets around behind the speaker anyway, and even if some did, it can't come back into the room again, because the soffit baffle stops it.

So there's another problem killed. SBIR from the front wall is gone. Impossible.

Then there's "edge diffraction", which is a bit more complex. It goes like this: remember that waves that are a lot shorter than the width of the speaker (higher frequencies) all go directly towards you, while ones that are a lot longer wrap around behind? OK, so what happens to the ones that are roughly the SAME width as the speaker? Well, they sort of try to wrap around, but they can't quite make it... and they also can't quite go directly forwards either! The problem happens at the front edges of the speaker cabinet, just where they waves are reaching the edges of the front baffle. They sort of want to go around, but they sort of can't, so there's a kind of "push pull" fight going on right at the edge, with part of the wave almost getting around the corner, and part not quite making it, and that creates all manner of ugly stuff, right at the edge of the box. (For those who really understand the technical issue here: Yeah, I know that explanation isn't accurate, but it's a good way of thinking about it to get the general idea.) So that's why it is called "edge diffraction". It's a problem, because it messes up the frequency repose, and the power response, and the phase response, for all frequencies where the wavelength is similar in size to the dimensions of the box. It creates interference patterns that mess things up. That's why many studio monitor speakers have beveled or rounded corners and edges: to reduce edge diffraction, and some speakers (such as many Genelec's) are even egg-shaped, totally curved, to reduce it even more. But you can't get rid of the problem completely. ... Unless you mount the speaker in a soffit! Since the front baffle of the soffit is basically an extension of the front of the speaker box, there is no edge! So there is no edge diffraction!

That's yet another issue that soffit mounting eliminates.

The list is growing:

- Power imbalance
- Front wall SBIR
- Comb filtering
- Edge diffraction

All of those are eliminated by putting your speakers in soffits. Gone. Not there. There are other things that soffit-mounting fixes too, but those are the main ones.

But what does that mean, in terms of how it sounds? Major, big-time improvements! First and foremost, the bass is much tighter and smoother, and extends down lower. None of those artifacts are there, so they cannot distort the bass response. All you hear is the pure, deep, focused, rich bass of your speakers. And since the low end is extended by the infinite baffle, the speakers actually sound bigger than they are. Then there's the mid range: since it is no longer muddied by the edge diffraction problem, that is cleaner, smoother, and better defined as well. And for the high end, the soffit helps with yet ANOTHER problem, which is impedance mismatch! I haven't mentioned that yet, but in brief simple terms, it works like this. The tweeter cone is a hard, rigid, massive solid object, and it is trying to transfer energy to a softy, mushy, springy, compressible, floppy fluid, called "air". That energy transfer is VERY inefficient, because the the two materials are so very different! Try flapping your hands up and down in air, and see how well you can move it around.... But if you flap your hands up and down underwater, you do a LOT better! You can swim in water, but you can't swim in air, because the "impedance" of the water is closer to the impedance of your hands, but the impedance of air is very different. So you can transfer your "flapping hand" energy to the water, much better than you can transfer it to the air, because the impedance is better matched. If you wanted to transfer "flapping hand" energy into air, then you could maybe attach ping-pong paddles to your hands, or better still, big pieces of cardboard or thin piece of plywood: That would improve the impedance of your hand a lot! It would be much more closely matched. The bigger the sheet of wood you used, the better it would be. You'd have to work harder, but you could move a LOT of air if you attached a really large piece of wood to your hand.... maybe the size of a soffit baffle, for example!

Speaker manufacturers go to a lot of trouble to carefully design the "wave-guides" around the tweeters of their speakers, to improve the impedance matching problem, so that the tweeter cone can transfer it's energy much more efficiently into the air. That's the reason for the curved shape plastic or metal "thingy" around the tweeter: to improve the impedance matching between the tweeter and the air... but that wave-guide is limited by the size of the box that the speaker is mounted in: it can't be bigger than the box! Unless you put it in a soffit....

Yup, you guessed: The soffit also improves the impedance matching of the tweeter to the air. Not by a lot, to be honest, but enough to be useful. So the high end is also cleaner, smoother, crispier, more "airy", better detailed, ... because the tweeter can do a better job of transferring all of its energy into the air..... (If you have ever heard what a tweeter sounds like when it is take out of its wave-guide , and just working in the open air, you have certainly noticed how tiny, thin, tinny and ridiculous it sounds! The same happens if you take your earbuds out of your ears, and hold them a couple of inches away from your ears: all the bass and most of the mid-range is gone, because your ear canal was providing the impedance matching).

In other words, the soffit does many, many things a once to greatly improve the full spectrum of sound coming out of your speakers.

In my opinion, tit's the best single thing you can do to a studio control room, and to your speakers. Everything else is "icing on the cake", but soffit-mounting your speakers is the cake itself. It makes a huge difference.

It's interesting that smaller speakers benefit from it more than large speakers. Most speakers will do great in soffits, and will pump out cleaner, deeper, smoother, tighter sound than you have ever heard them produce before. Because your soffits, if they are properly designed, will do exactly that.

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And one final thing, about orientation of your speakers. If the manufacturer gives you the option, then ALWAYS set them up vertically. FOr this reason:

As you can see, placing them horizontally can potentially produce interference artifacts that you will notice as you move your head around, side to side. That doesn't happen with vertical mounting, since you don't have ears on the top and bottom of your head! Your ears are on the sides of your head, so you are affected by this issue only for horizontal mounting. It doesn't affect you with vertical mounting.

There's more I could say about how to actually design your soffits properly, but that's an entire different thing. This is just about the acoustic reasoning behind why you should do it.


- Stuart -

[DYSTONIA]

Source of the post OK, back to "soffit-mounting" (a.k.a "flush mounting").

First, here's something I wrote a long time ago, and have been meaning to update. Most of it is still valid, but as the disclaimer says: "Sometimes you need to bend the rules to make it work for your room".

Wow, amazing to have that knowledge. I did read it and I will doing some tests with that information. I was trying to do a quick measurement with the full setup. I search on the internet for hours but I can never find any information on how to measure in REW with multiple subwoofers. Because I don't know what the crossover point is (now set at 80hz) and how loud I've to put the subwoofers in volume to match with the near fields. (See attachment). When the studio is done I will quit smoking haha....

In the mean while I will read your post 3 times, it's a lot of info haha. Also concluded that he speakers are a little bit to high, but that's an easy fix.