Our basement studio consists of a control room and a larger live room. We’re fairly experienced recordists, although not full-timers. Here’s a record we just did (it was not tracked in this space though)! We work on various genres, including punk, indie, acoustic/folk, as well as jazz, experimental, etc.
(For anyone curious, we’re a hybrid analog/digital studio, with a 1” Tascam 16-track -> Logic being our primary workflow-an emphasis on character over pristine sounds).
We’d like to make the best of the space we currently have. Eventually we’d consider a gut reno and new walls, potentially creating more isolation between the studio space and the living space upstairs, with a fabric ceiling, perhaps double leaf construction, changing room dimensions etc but we have some saving up to do first, and in the immediate term, some records to make.
So, our focus right now is on treatments and speaker placement, rather than a more comprehensive approach (though we'd be curious about suggestions for steps to take down the road). Our primary goal is a flat response in the control room and a good sounding, balanced live room - not too dead, not too live. We don’t care about sightlines to the live room (there is no window). We do want to preserve the natural light.
Less important right now is isolation. Right now, the neighboring house is vacant, but their living room is about 20 feet from the control room. Currently a pink noise test at 90 db in the control room results in less than 65 db right outside the window, so we’re not terribly concerned, though we recognize we might need to add a second glass door in the live room at some point to get it under the 55db noise limit for residential if recording drums etc after 9 pm.
Monitors are Mackie HR824. Unfortunately, the passive radiator design precludes the possibility of flushmounting. We also have a 10” Monoprice sub we can add if originating the low bass driver somewhere else in the room would give a better result
Current construction: Plush carpet over pad over concrete foundation, except where there is tile in the live room(which we’re interested in keeping, at least for now, we like the idea of brightening the upright piano with reflections). Ceiling construction is 1/2” drywall over manufactured I-beams. 7’9” ceilings, but there is 16” depth between the ceiling and the subfloor above, which suggests possibilities for stuffing this space with insulation at some point. Lighting is recessed lighting, older cans retrofitted with LED bulbs. There’s no insulation in the HVAC channels that run above the live room, but resonant “drum” effects from these are currently minimal. Exterior walls seem to be poured concrete (at this basement level).
Budget—currently aiming for $2000 supplies in the short term. Can go over if necessary.
Good news is that we have a lot of panel absorbers (mostly 703). These do not have membranes.
17 - 48x24x4 with 2” air gap
7 - 48x24x4
11 - 48x24x 6
1 - 48x 24 x 2
2 - 88 by 54 x 1
1 triangular chunk, 53” high, 24” sides
As necessary, we could sacrifice some of these to build superchunks (or get more supplies).
Our control room is 16’ by 12’ 6”, with 7’9” ceilings, and as you can see, an L shape in the back that extends another 5’4” to the door. This area is 6’ wide.
This is a first pass at REW measurements, with no treatments, with some traps piled in corners, and some more added to back wall (these were not serious attempts at treating the room, just experiments, as we want to commit to room orientation etc before drilling walls for permanent installation of absorbers.. Monitors were set in equilateral triangle with tweeters at ear level (4'4"), listening position at the 38% "starting point" from the front wall. I had them set as close as possible to the wall before they bump up against the builtins.
Here is the REW measurement file.
Here is the sketchup file.
Questions:
1). We figured we’d orient the room with the monitors against the short (12’6”) wall. An alternative would be placing monitors against the window on the 16” wall. Any reason that would work better given the shape/dimensions?
2) You’ll notice in the front of the control room there is a large builtin bookshelf, and at the top of the wall, a soffit which (unfortunately) contains the HVAC supply for the floor upstairs. The soffit can’t be removed, but the shelves that extend down to the floor could. Should we pull out the builtin bookshelves completely before moving ahead? Or should we just fill it with 703? Or something else?
3) You’ll notice the control room is L-shaped. Would it be worth it to build a simple wall to close off the area by the closet and create a sort of vestibule and make the room symmetrically rectangular?
4). Where should we place absorption? Where should we place the speakers? How low should we run the mains? (Roll off can be set at 37, 47, or 80, or I suppose ).
5.). I know nobody likes carpet in the live room. I was thinking that rather than pull it out completely and refloor the whole space, we could just figure out a dedicated drum zone and create a small area with wood floor? Sensible?
Basement Studio with some layout quirks
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swimtwobirds
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garethmetcalf
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Re: Basement Studio with some layout quirks
Hi
Just thought I'd comment to say you can soffit mount the mackie monitors - I have the mk1 version and plan to do it. There's a few threads on this forum with people who've done it with these speakers, this is a good one: http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8205
Good luck!
Gareth
Just thought I'd comment to say you can soffit mount the mackie monitors - I have the mk1 version and plan to do it. There's a few threads on this forum with people who've done it with these speakers, this is a good one: http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8205
Good luck!
Gareth
Derbyshire, England
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Soundman2020
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Re: Basement Studio with some layout quirks
Hi there "swimtwobirds", and Welcome! 
That's not to say that you won't be able to anything with that room: Just that your goal of "flat response" is not on the cards. It can be sort-of flattish if you treat the hell out if it, and it can certainly be quite good! Not a problem.
Ummm... nope! Ain't gonna happen! There's a basic misunderstanding of sound levels here. Let me walk you through this:
You tested with 90 dB pink noise. Drums are one thousand times louder. An acoustic drum kit played hard can put out 120 dBC. The decibel scale is logarithmic, so each time you go up ten points, you have ten times the intensity. Going from 90 to 100 is ten times the intensity. 90 to 110 is one hundred times the intensity. 90 to 120 is one thousand times the intensity. So you are underestimating the actual sound level that you will be dealing with by a factor of one thousand.
In addition, pink noise is constant level with the same power in each octave band. Drums are not. Drums are all about impact: sudden very sharp, very loud percussive events, with most of the power in the low frequencies. Nothing at all like pink noise. Because pink noise is full-spectrum, constant power, and unvarying, it is actually a very restful sound, and will put you to sleep, even at fairly high levels. You can't say the same about drums! The sound is repetitive, and certainly not restful. In other words, your neighbors might not even notice 60 dBC of pink noise coming over your wall, but the absolutely and without any doubt will notice 60 dBC of drums!
So, to put all the above in perspective: There's no way on God's green earth that adding a door will increase your isolation sufficient to isolate drums! Nope. Just nope.
You estimate that right now you have about 25 dB of isolation, which is rather poor. A typical house wall should get around 30, so you already have a problem there some place. So here's the bottom line: When you are playing drums at 120 dB, it will be coming through your walls at about 95 dB. Adding that second door might, perhaps, maybe, with lots of luck, bring that down to 91 or 92. You say your neighbors are 20 feet away, so you do have the benefit of distance attenuation, but even so, your drums are going to be hitting their place at around 80 dB, give or take a bit.
That's the real situation.
If you can persuade our drummer to play very quietly on light sticks, your level inside might drop to 110 dB, but even then your level at the neighbor's house will be north of 70 dB.
You say that where you live, the legal limit for nuisance noise is 55 dB. That's pretty high: most places are more like 40, and even lower. So you get 55, which is great. But even so, you are a full 25 dB short of where you need to be. Increasing your isolation by 25 dB, from the current 25 to the 50 you would need, is a tall order. You did ask for advice on what you might do "down the road" to get where you want to go, so here it is: You will, without any doubt at all, need to build a proper "room-in-a-room" system. Full two-leaf fully-decoupled MSM isolation is in your future.
But that's the future, not now, so let's get on to what you actually asked for:
Don't believe me? Take a look here: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 The final monitors in that room are Eve Audio SC-407's. The are rear ported, with huge, massive rear bass-reflex slots on them. Look at the results. I think it's fair to say that they have been successfully soffit-mounted...
I used to think the same way you do: that rear-ported speakers could not be soffit mounted... Until I looked into the theory, and found that it isn't so. With good design, they can be. So don't rule out soffit mounting. It's one of the biggest things you can do to improve the acoustics of your room, since in effect it takes the speakers out of the room and embeds them in the front wall. So all of the artifacts associated with having speakers in the room, close to the front wall, simply disappear, and you also get automatic correction of the power imbalance that affect all small speakers.
That's gotta go! Bad, bad, bad....
Not "at some point", but NOW! Pull off that drywall, stuff the joists with insulation, and you have an amazingly better studio. To start with, the height is now 9' 1-1/2"! 
Your room profile is no longer square, you pass all three critical tests, you have a ratio of 1 : 1.36 : 1.75 which is Pretty Darn Good, and the room actually stands a chance of getting a lot flatter.
If that were my place, you'd see me out there right now in overalls, happily ripping of that drywall, singing and dancing, because my "mediocre-at-best" room is becoming my "really nice, flat" room, by doing one simple thing.
Of course, this will reduce your isolation to the rest of the house, but you aren't getting much isolation anyway, so that's probably not a big deal.
Great! Some of those can be used as-is, probably. The rest can be taken apart and re-used more effectively.
Your setup is reasonable, but can be improved...
Yeah, I know: you've probably seen that famous diagram in dozens of places, all over the internet, and even in text books, But I'm convinced that the guy who first drew that must be an alien, with his ears on stalks that he places over his eyes when listening...
In reality, your ears should be on-axis to the speakers, not your eyes. That's sort to obvious when you think about it! Speaker manufacturers go to major efforts to make sure that their speakers produce the best possible, flattest, cleanest sound on-axis, and that degrades as you get further and further off-axis. So it just makes sense to put your ears where the speakers sounds flattest..... unless you can see the sound coming at you, with your eyes.
In fact, because of the way our ears work, it turns out that you get the best possible sound with the speaker axis grazing past the edge of your ear tip, maybe even an inch or two away.
So here's how your speaker and mix position geometry should be set up for your room:
That's the way I'd set it up initially. There might be a better spot around there, which you could find by careful, systematic analysis with REW once the initial treatment is in place, but it won't be far from there.
- Stuart -
OK, no problem with that! So this is purely "treat the place as well as possible, within the limitations imposed by the current dimensions and materials".but we have some saving up to do first, and in the immediate term, some records to make.
Right. They go together, but in the opposite order: First comes speaker placement, then comes the treatment that is appropriate for that speaker geometry.So, our focus right now is on treatments and speaker placement,
Bad news, I'm afraid: You wont be getting ruler-flat response in that room: The ceiling is very low, the section is square, the length is rather large compared to the height, and that "L" is a problem... there will be two different decay rates in there, and they will differ by frequency as well.Our primary goal is a flat response in the control room --- control room is 16’ by 12’ 6”, with 7’9” ceilings, and as you can see, an L shape in the back that extends another 5’4” to the door.
That's not to say that you won't be able to anything with that room: Just that your goal of "flat response" is not on the cards. It can be sort-of flattish if you treat the hell out if it, and it can certainly be quite good! Not a problem.
Pink noise is great for speaker calibration, room testing, and many other things, but it's not much use for testing isolation. You should test that with real music played loud either live or on a set of full-range speakers. You also didn't say if you tested on "A" weighting, or "C", and if you used "fast" or "slow" response. That's important. There can be huge differences.Currently a pink noise test at 90 db in the control room results in less than 65 db right outside the window,
More bad news: Just adding a door will not do what you are hoping it will do. Isolation is a system, and it involves the entire room, on all directions and all aspects. Right now, you only have single-leaf walls, so you are limited by the equations known as "mass law", which means that your second door would basically accomplish nothing. The walls are the weakest link, so improving only the door is not useful. In order to get an increase of 10 dB in isolation, you'd need to quadruple the mass that you currently have on your walls and ceiling. Mass law says that you get a 6 dB increase each time you double the mass, but that's theoretical, and real-world is not so kind to you: more like 4 to 5 dB each mass doubling.though we recognize we might need to add a second glass door in the live room at some point to get it under the 55db noise limit for residential
to get it under the 55db noise limit for residential if recording drums etc after 9 pm.
Ummm... nope! Ain't gonna happen! There's a basic misunderstanding of sound levels here. Let me walk you through this:You tested with 90 dB pink noise. Drums are one thousand times louder. An acoustic drum kit played hard can put out 120 dBC. The decibel scale is logarithmic, so each time you go up ten points, you have ten times the intensity. Going from 90 to 100 is ten times the intensity. 90 to 110 is one hundred times the intensity. 90 to 120 is one thousand times the intensity. So you are underestimating the actual sound level that you will be dealing with by a factor of one thousand.
In addition, pink noise is constant level with the same power in each octave band. Drums are not. Drums are all about impact: sudden very sharp, very loud percussive events, with most of the power in the low frequencies. Nothing at all like pink noise. Because pink noise is full-spectrum, constant power, and unvarying, it is actually a very restful sound, and will put you to sleep, even at fairly high levels. You can't say the same about drums! The sound is repetitive, and certainly not restful. In other words, your neighbors might not even notice 60 dBC of pink noise coming over your wall, but the absolutely and without any doubt will notice 60 dBC of drums!
So, to put all the above in perspective: There's no way on God's green earth that adding a door will increase your isolation sufficient to isolate drums! Nope. Just nope.
You estimate that right now you have about 25 dB of isolation, which is rather poor. A typical house wall should get around 30, so you already have a problem there some place. So here's the bottom line: When you are playing drums at 120 dB, it will be coming through your walls at about 95 dB. Adding that second door might, perhaps, maybe, with lots of luck, bring that down to 91 or 92. You say your neighbors are 20 feet away, so you do have the benefit of distance attenuation, but even so, your drums are going to be hitting their place at around 80 dB, give or take a bit.
That's the real situation.
If you can persuade our drummer to play very quietly on light sticks, your level inside might drop to 110 dB, but even then your level at the neighbor's house will be north of 70 dB.
You say that where you live, the legal limit for nuisance noise is 55 dB. That's pretty high: most places are more like 40, and even lower. So you get 55, which is great. But even so, you are a full 25 dB short of where you need to be. Increasing your isolation by 25 dB, from the current 25 to the 50 you would need, is a tall order. You did ask for advice on what you might do "down the road" to get where you want to go, so here it is: You will, without any doubt at all, need to build a proper "room-in-a-room" system. Full two-leaf fully-decoupled MSM isolation is in your future.
But that's the future, not now, so let's get on to what you actually asked for:
Nope! Not true! Gareth is absolutely correct: it is possible to soffit-mount those, if the soffit is designed and built correctly.Monitors are Mackie HR824. Unfortunately, the passive radiator design precludes the possibility of flushmounting.
Don't believe me? Take a look here: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 The final monitors in that room are Eve Audio SC-407's. The are rear ported, with huge, massive rear bass-reflex slots on them. Look at the results. I think it's fair to say that they have been successfully soffit-mounted...
I used to think the same way you do: that rear-ported speakers could not be soffit mounted... Until I looked into the theory, and found that it isn't so. With good design, they can be. So don't rule out soffit mounting. It's one of the biggest things you can do to improve the acoustics of your room, since in effect it takes the speakers out of the room and embeds them in the front wall. So all of the artifacts associated with having speakers in the room, close to the front wall, simply disappear, and you also get automatic correction of the power imbalance that affect all small speakers.
Current construction: Plush carpet over pad over concrete foundation,
That's gotta go! Bad, bad, bad....Yes, yes, yes! Keep it, for sure! That's an excellent floor, acoustically.except where there is tile in the live room(which we’re interested in keeping,
Ceiling construction is 1/2” drywall over manufactured I-beams. 7’9” ceilings, but there is 16” depth between the ceiling and the subfloor above, which suggests possibilities for stuffing this space with insulation at some point.
Not "at some point", but NOW! Pull off that drywall, stuff the joists with insulation, and you have an amazingly better studio. To start with, the height is now 9' 1-1/2"! Your room profile is no longer square, you pass all three critical tests, you have a ratio of 1 : 1.36 : 1.75 which is Pretty Darn Good, and the room actually stands a chance of getting a lot flatter.If that were my place, you'd see me out there right now in overalls, happily ripping of that drywall, singing and dancing, because my "mediocre-at-best" room is becoming my "really nice, flat" room, by doing one simple thing.
Of course, this will reduce your isolation to the rest of the house, but you aren't getting much isolation anyway, so that's probably not a big deal.
So put some in! Go buy a roll of good quality 1" duct liner, open up your ducts, and install it. Or higher an HVAC contractor to do it for you: It's a fairly big job.There’s no insulation in the HVAC channels that run above the live room,
So why are you only getting 25 dB of isolation? The mystery deepens....Exterior walls seem to be poured concrete (at this basement level).
Good news is that we have a lot of panel absorbers (mostly 703). These do not have membranes.
Great! Some of those can be used as-is, probably. The rest can be taken apart and re-used more effectively.As necessary, we could sacrifice some of these to build superchunks
With those dimensions, room orientation is a given. Or at least it's a given, if you hope to have a decent chance at getting good response. The only correct orientation is exactly as you show it.just experiments, as we want to commit to room orientation etc before drilling walls
Your setup is reasonable, but can be improved...
Can I ask a silly question? Do you have your ears on the front of your eyeballs, or do you have your ears sticking out the side of your head? If your ears are on your eyeballs, then the "equilateral triangle" thing is fine. Your ears are on-axis to the speakers. But if you have your ears in the same place most people do, a few inches out the sides of your eyes, a few inches back, and a little lower down, then that's not a good setup.. Monitors were set in equilateral triangle
Yeah, I know: you've probably seen that famous diagram in dozens of places, all over the internet, and even in text books, But I'm convinced that the guy who first drew that must be an alien, with his ears on stalks that he places over his eyes when listening...
In reality, your ears should be on-axis to the speakers, not your eyes. That's sort to obvious when you think about it! Speaker manufacturers go to major efforts to make sure that their speakers produce the best possible, flattest, cleanest sound on-axis, and that degrades as you get further and further off-axis. So it just makes sense to put your ears where the speakers sounds flattest..... unless you can see the sound coming at you, with your eyes.
In fact, because of the way our ears work, it turns out that you get the best possible sound with the speaker axis grazing past the edge of your ear tip, maybe even an inch or two away.
So here's how your speaker and mix position geometry should be set up for your room:
That's the way I'd set it up initially. There might be a better spot around there, which you could find by careful, systematic analysis with REW once the initial treatment is in place, but it won't be far from there.
"builtins"? What do you mean by "builtins"? That can have many meanings....I had them set as close as possible to the wall before they bump up against the builtins.
Ahh! So THAT'S what the "builtins" are! Yup, pull them out. Your speakers need to get up much closer to the front wall. Just a 4" gap, for a 4" panel of 703.The soffit can’t be removed, but the shelves that extend down to the floor could. Should we pull out the builtin bookshelves completely before moving ahead?
Yes, if you can afford it, but on a small budget like yours, it might not be possible.3) You’ll notice the control room is L-shaped. Would it be worth it to build a simple wall to close off the area by the closet and create a sort of vestibule and make the room symmetrically rectangular?
First things first: Get the shelves out the way, build your wall to make the room rectangular, set up your geometry as above, get everything else out of the room except the speakers, the stands, and your chair, calibrate REW for 80 dBC on each speaker (86 dBC with both), using a proper hand.held sound level meter, then do a set of three tests with REW: Just L, just R, then both L and R together. Upload the MDAT file to a file sharing services, such as Dropbox, then post the link here. That will be your "baseline" test: completely empty room. That's as bad as it gets: really ugly response, but all of the modal and SBIR stuff is in there, so it's the start you need to be able to know what to treat, and also to see how things change as you treat.4). Where should we place absorption? Where should we place the speakers? How low should we run the mains? (Roll off can be set at 37, 47, or 80, or I suppose ).
It's not that people don't like it: Rather, it's that it makes no sense at all. Carpet does the exact opposite of what small rooms need. It sucks out the highs, pulls out some of the mids, randomly, on a curve that sort of increases with frequency, and does nothing at all for the lows. What small rooms need is massive absorption for the lows, smooth absorption in the mids, decreasing with frequency, and very little in the highs. So if you insist on keeping carpet in your room, it will sound dull, honky, thunky, boomy, ... If that's the sound you want for all of your music, then great! Keep the carpet! But if you want pleasant response, then get rid of it.5.). I know nobody likes carpet in the live room
Nope! Not! In fact, backwards! Drums are usually set up on large hard floors with a big patch of carpet under them, to reduce the shrillness of the cymbals and snare, and also prevent the kit from sliding all over the floor. So setting up yours in a carpeted room with a patch of hard floor under it, will make it sound rather strange.... and keep your drummer busy chasing the kit around as he plays....I was thinking that rather than pull it out completely and refloor the whole space, we could just figure out a dedicated drum zone and create a small area with wood floor? Sensible?
- Stuart -
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swimtwobirds
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- Location: Silver Spring MD
Re: Basement Studio with some layout quirks
Thank you so much, this is extraordinarily helpful.
Based on this feedback, I think it makes the most sense to break this work into two phases.
Phase 1
Remove bookshelves
Remove carpet
Construct wall lopping off the "L" in control room
Measure room and place treatments
Phase 2 (when time & budget permit)
build soffit mounts
Newer flooring over concrete subfloor
Remove drywall ceiling in control room, add insulation
Insulate HVAC
additional isolation measures
I appreciate the explanation for taking the drywall ceiling down immediately, and the rationale is sound. Unfortunately, the loss of isolation to the rest of the house would be pretty extreme (there's no drywall over the laundry room depicted in the sketchup and so we know from the sound transmitted from that room to the floor above that this would be untenable for the control room without some additional measures (I assume, adding mass to the deck with a couple layers of drywall caulked in place between the joists). So we'll have to leave that for down the road. Does that make sense?
Based on this feedback, I think it makes the most sense to break this work into two phases.
Phase 1
Remove bookshelves
Remove carpet
Construct wall lopping off the "L" in control room
Measure room and place treatments
Phase 2 (when time & budget permit)
build soffit mounts
Newer flooring over concrete subfloor
Remove drywall ceiling in control room, add insulation
Insulate HVAC
additional isolation measures
I appreciate the explanation for taking the drywall ceiling down immediately, and the rationale is sound. Unfortunately, the loss of isolation to the rest of the house would be pretty extreme (there's no drywall over the laundry room depicted in the sketchup and so we know from the sound transmitted from that room to the floor above that this would be untenable for the control room without some additional measures (I assume, adding mass to the deck with a couple layers of drywall caulked in place between the joists). So we'll have to leave that for down the road. Does that make sense?
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swimtwobirds
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- Location: Silver Spring MD
Re: Basement Studio with some layout quirks
Here is the room response mdat file. Unfortunately we weren't able to build that extra wall yet. Would love advice on where to start with room treatment.
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Soundman2020
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Re: Basement Studio with some layout quirks
Before you can start with room treatment, you first need to fix the rather large difference between your speakers! The graph below shows just that: the difference in SPL between your left and right speakers, across the full spectrum: That's basically showing the right signal subtracted from the left signal, so it's the difference between them, which is why it is centered on 0 dB. Where the curve is above the line, the left speaker is louder at that frequency. Where the curve is below the line, the left speaker is quieter than the right speaker. As you can see, there are wild swings, and in places one speaker is twice as loud as the other, subjectively (difference of 10 dB).Here is the room response mdat file.... Would love advice on where to start with room treatment.
And the same thing, just for the low end: Here's what it should look like for a really good room with careful balancing, both acoustically and electronically: That's just for the low end (20Hz to 500 Hz. Here's a full spectrum view for the same room: The purple line there shows the total frequency response curve for the room, from 17 Hz to 22 kHz, and the green line down the bottom shows the difference between the left and right channels. That's about as good as you it gets, and yours probably won't get that good, but it certainly does need to get a lot better!
Here's a more direct comparison of your speakers, showing the individual levels of each speaker, in the low end of the spectrum:
So the very first thing you need to do is to figure out why there's such a big difference between the speakers, and fix that. It might be the speakers themselves, or the way you have them placed in the room (did you set them up exactly like I showed, very accurately), or it might be the room itself: something about the room is not symmetrical.
What treatment do you have in there right now?
Photos... ??
- Stuart -
(PS. The overall response doesn't look too bad, and can be treated quite well, but only once the speakers are behaving the same.)
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swimtwobirds
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- Location: Silver Spring MD
Re: Basement Studio with some layout quirks
Hmm. The placement was verified with a laser tape measure. Would the "L" shape of the room account for the asymmetry? As noted above, we'd discussed putting a wall in to make the room symmetrical but have not been able to yet.
Alternatively, as you can see from the large image at the top of the thread, we have exterior walls on one side but wood-framed drywall on the other, might that cause this asymmetry? (again, thanks for the help!)
Alternatively, as you can see from the large image at the top of the thread, we have exterior walls on one side but wood-framed drywall on the other, might that cause this asymmetry? (again, thanks for the help!)
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swimtwobirds
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Re: Basement Studio with some layout quirks
Update:
I've pulled the carpet from the room and constructed the wall to create an actual rectangle instead of the awkward L shaped space. I've updated the Sketchup file to reflect the changes in the room geometry and created new baseline measurements for the untreated room.
The monitors are precisely placed as specified in the diagrams upthread.
The response is more symetrical, especially in the low end (some mid/high differences likely related to racks/mix desk etc. But I'm ready to go with starting to place room treatment and would welcome advice.
Thank you so much (Stuart and everyone else) for any guidance you can provide.
I've pulled the carpet from the room and constructed the wall to create an actual rectangle instead of the awkward L shaped space. I've updated the Sketchup file to reflect the changes in the room geometry and created new baseline measurements for the untreated room.
The monitors are precisely placed as specified in the diagrams upthread.
The response is more symetrical, especially in the low end (some mid/high differences likely related to racks/mix desk etc. But I'm ready to go with starting to place room treatment and would welcome advice.
Thank you so much (Stuart and everyone else) for any guidance you can provide.
Last edited by swimtwobirds on Sat Dec 30, 2017 6:49 am, edited 1 time in total.
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Soundman2020
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Re: Basement Studio with some layout quirks
... Something went wrong there! There's only one single measurement in there, clearly from a sub. I'd need the full set of measurements.and created new baseline measurements for the untreated room
I'm not sure if you have seen this, but recently I wrote a post on how to set up REW, calibrate it, and take a full set of measurements: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122
- Stuart -
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swimtwobirds
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Re: Basement Studio with some layout quirks
Whoops! Here is the corrected link.. I did my best to follow your directions.
(The subwoofer measurement, incidentally, is with the subwoofer centered in the room on the front wall, 6 inches from the wall. No EQ or crossover engaged on anything.)
(The subwoofer measurement, incidentally, is with the subwoofer centered in the room on the front wall, 6 inches from the wall. No EQ or crossover engaged on anything.)
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Soundman2020
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Re: Basement Studio with some layout quirks
Much, MUCH better than your original! Day and night difference. Considering the size of the room, that's actually a very decent response, and it can probably be tamed rather nicely.
The difference between the speakers is also greatly improved from about 100 Hz upwards. There's still some minor differences, but a huge improvement. However, at the bottom end, from about 100 Hz down, the left speaker is putting out more energy than the right, especially between around 40 Hz and 70 Hz. It can probably be fixed electronically, with a good crossover.
Does your sub have a built in cross-over? How do you have the controls set on your speakers right now? From what you said, it seems you have everything set flat right now? If there's a cross-over on the sub where your main speakers can be plugged into the back of the sub and be filtered by the sub, then I would give that a try. Set the crossover point a bit higher than normal, say around 90 Hz, and roll off the bass your mains: set the "Low Freq" switch to "80 Hz Low Cut", and also set the "High Freq" to "-2dB" (that last one might be too much for the highs, but let's give it a try anyway).
It's not necessary to go crazy with fine tuning all of that now: the results are good enough to start working on your treatment. But it might be instructive and interesting for you to try it, to better understand some of the concepts here, and better understand your room.
- Stuart -
The difference between the speakers is also greatly improved from about 100 Hz upwards. There's still some minor differences, but a huge improvement. However, at the bottom end, from about 100 Hz down, the left speaker is putting out more energy than the right, especially between around 40 Hz and 70 Hz. It can probably be fixed electronically, with a good crossover.
Does your sub have a built in cross-over? How do you have the controls set on your speakers right now? From what you said, it seems you have everything set flat right now? If there's a cross-over on the sub where your main speakers can be plugged into the back of the sub and be filtered by the sub, then I would give that a try. Set the crossover point a bit higher than normal, say around 90 Hz, and roll off the bass your mains: set the "Low Freq" switch to "80 Hz Low Cut", and also set the "High Freq" to "-2dB" (that last one might be too much for the highs, but let's give it a try anyway).
Generally it's a bad thing to have your sub centered. That can set up strange patterns of low-frequency sound in the room. It's more usual to offset the sub towards one side of the room or the other. The best location can be found by "trial and error". It's often easier to find that best spot by flipping things around backwards: set up the sub where your head would normally be, and move your head around the places where you think the sub should go, listening carefully until you find the spot that has the best low end balance. Even better is to do that using REW instead of your head: Do a series of tests with the test mic in many, many possible locations, separated by just an inch or so in bot "X" and "Y" directions, (and even in "Z", if you really want perfection), then look for the graph that has the smoothest low end, and place your sub at the point where the mic was for that test. Also use the "normal" and "inverted" phase switch on the sub at each locations: very often inverting the phase of the sub can get you a dramatic improvement (or detriment!).The subwoofer measurement, incidentally, is with the subwoofer centered in the room on the front wall, 6 inches from the wall.
It's not necessary to go crazy with fine tuning all of that now: the results are good enough to start working on your treatment. But it might be instructive and interesting for you to try it, to better understand some of the concepts here, and better understand your room.
- Stuart -
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swimtwobirds
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Re: Basement Studio with some layout quirks
Here's some updated measurements. I ran individual measurements with the mains using the lo-cut engaged at 80hz and the hi-end turned down to -2db. I also engaged the built-in crossover on the sub at 90hz. I also ran a L+R and L+R +SUB with phase at 0 and 180--first using separate feeds to the sub and mains, (output A-> mains, output b-> sub) and then just using one signal and passing through to the mains (Output A->sub> mains)
I suspect the difference in low end energy between the two speakers is resulting from difference in response from the difference in construction between exterior walls (drywall and insulation over poured concrete foundation over left wall and back wall and half of the front wall) and interior walls (drywall over air over drywall on the right half of the front wall and the right wall).
I arrived at the odd centered sub placement through some trial and error and while I'm certain there's much value to be had in some additional fine tuning in the future, I'm anxious to get some treatment in the room! Let me know what you think and again thank you, and happy new year!
I suspect the difference in low end energy between the two speakers is resulting from difference in response from the difference in construction between exterior walls (drywall and insulation over poured concrete foundation over left wall and back wall and half of the front wall) and interior walls (drywall over air over drywall on the right half of the front wall and the right wall).
I arrived at the odd centered sub placement through some trial and error and while I'm certain there's much value to be had in some additional fine tuning in the future, I'm anxious to get some treatment in the room! Let me know what you think and again thank you, and happy new year!
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Soundman2020
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Re: Basement Studio with some layout quirks
I'm curious about your sub: It's not doing much "subing" (to invent a new term....). It has a ten inch driver, it has a bass-reflex type sub, and the manual and specs claim that it goes down to 20 Hz. But it doesn't! It cuts out at about 36 Hz, and by 32 Hz it is fully -10 dB down. At 30 Hz it's taken a nose dice way down to -24 dB! and at 20 Hz (where it is still supposed to be very much alive, according to specs), it just isn't there at all: It's over -50 dB down!
And even more curiously, you get pretty much the exact same roll-off from your main speakers, WITHOUT the sub!
That's one hell of a roll-off, for something that is designed to go low.... so I'm suspecting that it's not a sub problem... it's a signal chain problem! I would check your entire signal chain, to find out where you have some type of filter applied, that is killing your low end. There's something in the signal chain that is massively rolling off the bass, very steeply, starting at about 36 Hz. Perhaps you have a "low cut" filter applied to your mic channel on the console? Or to the channels you are using for the signal coming out of REW? Or some other type of filter? I'm having a hard time believing that your sub produces nothing at all below roughly 33 Hz, when it is designed and spec'd to go down to 20.
The sub is clearly working, doing its job. The crossover is fine, and you need the phase switch set to flat, not inverted, for the current setup. But something is slicing off all your low end, and that needs to be found and dealt with.
So please take a careful look at your signal chain and fix whatever it is that filtering your bass so steeply. The entire response is looking very much like you have some type of EQ going on: Are you certain that you don't have a graphic equalizer, parametric equalizer, or some type of digital filtering going on? Perhaps some type of software filter in your computer? The response does not look right in general, for that room, untreated, with those speakers. Please double-check the REW setup, calibration, and testing instructions. Something seems "off"...
Two photos, together, same size, same viewpoint, for easy comparison:
As you can see, the setup does not seem to be the same.
Without changing anything in the room, please measure this distance:
The toe-in angle on the speakers does not seem to be correct either: They do not seem to be aimed at the correct point in the room, which is 13.75" BEHIND the mix position, or 88.75" from the front wall: From that photo, the speakers appear to be aimed IN FRONT of the mix position. And assuming the photos shows how you had the measurement mic set up, that's also not correct. The mic appears to be aimed straight forward, directly at the front wall. Did you follow this setup instructions when you did the tests? : http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122
The trouble with your room right now, is that I'm not confident that the data I'm seeing is an accurate representation of the way the room is really responding: Therefore, it would not be a good idea to start treating it yet. According to your REW data so far, the room has no response at all below about 70Hz, which is VERY strange, since that's where ALL of the big problems are in a small room. Either your sound system is incapable of producing low-end sound sufficient to trigger the real response (which I very much doubt, based on the equipment you are using!), or there's something in the signal chain that is hiding reality. Either way, we are not seeing what the room is actually doing in the low end, and since that's undoubtedly where the first wave of treatment will be needed, there's no point in proceeding until we fund the problem in your signal chain, and fix it.
Please describe the complete signal path, from the point where the signal goes out of the REW software to the physical hardware, up to the point where it comes back into REW from the physical hardware.
Once we are sure that we have a valid set of data that really does show how the room is responding, then we an start with the room tuning process, which involves treatment.
- Stuart -
And even more curiously, you get pretty much the exact same roll-off from your main speakers, WITHOUT the sub!
That's one hell of a roll-off, for something that is designed to go low.... so I'm suspecting that it's not a sub problem... it's a signal chain problem! I would check your entire signal chain, to find out where you have some type of filter applied, that is killing your low end. There's something in the signal chain that is massively rolling off the bass, very steeply, starting at about 36 Hz. Perhaps you have a "low cut" filter applied to your mic channel on the console? Or to the channels you are using for the signal coming out of REW? Or some other type of filter? I'm having a hard time believing that your sub produces nothing at all below roughly 33 Hz, when it is designed and spec'd to go down to 20.
The sub is clearly working, doing its job. The crossover is fine, and you need the phase switch set to flat, not inverted, for the current setup. But something is slicing off all your low end, and that needs to be found and dealt with.
So please take a careful look at your signal chain and fix whatever it is that filtering your bass so steeply. The entire response is looking very much like you have some type of EQ going on: Are you certain that you don't have a graphic equalizer, parametric equalizer, or some type of digital filtering going on? Perhaps some type of software filter in your computer? The response does not look right in general, for that room, untreated, with those speakers. Please double-check the REW setup, calibration, and testing instructions. Something seems "off"...
That's possible, but I would have guessed that things are the other way around! It's the left channel that shows the low-end resonance more than the right channel.I suspect the difference in low end energy between the two speakers is resulting from difference in response from the difference in construction between exterior walls (drywall and insulation over poured concrete foundation over left wall and back wall and half of the front wall) and interior walls (drywall over air over drywall on the right half of the front wall and the right wall).
Are you sure about that? Here's what I get when I did an attempt to roughly match the point of view of the camera when you took the photo of the room, to your SketchUp model with the speakers inserted as per the layout I did:The monitors are precisely placed as specified in the diagrams upthread.
Two photos, together, same size, same viewpoint, for easy comparison:
As you can see, the setup does not seem to be the same.
Without changing anything in the room, please measure this distance:
The toe-in angle on the speakers does not seem to be correct either: They do not seem to be aimed at the correct point in the room, which is 13.75" BEHIND the mix position, or 88.75" from the front wall: From that photo, the speakers appear to be aimed IN FRONT of the mix position. And assuming the photos shows how you had the measurement mic set up, that's also not correct. The mic appears to be aimed straight forward, directly at the front wall. Did you follow this setup instructions when you did the tests? : http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122
You seem to be a little confused here: Treating the room IS tuning the room! Room tuning starts out by analyzing the room to understand it, optimizing the layout/geometry, then analyzing some more. Based on that, the next step in the room tuning process is to add treatment that deals with the worst issues, the analyze again. Add treatment to deal with the remaining worst issues, the analyze again. Repeat, over and over, until the desired result has been achieved or until you run out of money, or until you out of space to apply more treatment, or until you run out of patience. If you DID manage to get decent acoustic response (phase response, NOT frequency response) in the room, then it might be eligible for additional digital tuning, but that's the very last step, the "icing on the cake", and can ONLY be done if the phase response allows it. Room tuning is all of the above, but mostly it is about analyzing the actual measured response at each step, then designing treatment to deal with whatever is the "biggest remaining problem" at that step.while I'm certain there's much value to be had in some additional fine tuning in the future, I'm anxious to get some treatment in the room!
The trouble with your room right now, is that I'm not confident that the data I'm seeing is an accurate representation of the way the room is really responding: Therefore, it would not be a good idea to start treating it yet. According to your REW data so far, the room has no response at all below about 70Hz, which is VERY strange, since that's where ALL of the big problems are in a small room. Either your sound system is incapable of producing low-end sound sufficient to trigger the real response (which I very much doubt, based on the equipment you are using!), or there's something in the signal chain that is hiding reality. Either way, we are not seeing what the room is actually doing in the low end, and since that's undoubtedly where the first wave of treatment will be needed, there's no point in proceeding until we fund the problem in your signal chain, and fix it.
Please describe the complete signal path, from the point where the signal goes out of the REW software to the physical hardware, up to the point where it comes back into REW from the physical hardware.
Once we are sure that we have a valid set of data that really does show how the room is responding, then we an start with the room tuning process, which involves treatment.
- Stuart -
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swimtwobirds
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Re: Basement Studio with some layout quirks
Sorry if I wasn't clear, that photo was mostly to demonstrate basic room orientation after we pulled the carpet & shelving etc out--not actual measured speaker/mic placement--it was taken before we did accurate placement and took measurements. The measurement you requested between the speakers was 65.6" Pretty dang close!Soundman2020 wrote:Are you sure about that? Here's what I get when I did an attempt to roughly match the point of view of the camera when you took the photo of the room, to your SketchUp model with the speakers inserted as per the layout I did:The monitors are precisely placed as specified in the diagrams upthread.
Two photos, together, same size, same viewpoint, for easy comparison:
As you can see, the setup does not seem to be the same.
Without changing anything in the room, please measure this distance:
The mic angle used was 60 degrees, as per instructions and the toe-in angle is appropriately behind-the-head.
I too was puzzled about the lack of low end response from the sub! However, I came across this test data which seems to indicate that the stated specs for the Monoprice 60599 may not actually match performance (or more precisely, while Monoprice does claim that it gets down to 20hz, they don't don't say -3db). Granted, this is a CEA-2010 test rather than a sweep measurement, so maybe it's irrelevant and I'm misinterpreting.
Please describe the complete signal path, from the point where the signal goes out of the REW software to the physical hardware, up to the point where it comes back into REW from the physical hardware.
This is the current signal chain:
REW->Focusrite Scarlett 2i4 ->Monoprice balanced TRS stereo pair -> Presonus Central Station -> Monoprice balanced TRS stereo pair -> Subwoofer -> Monoprice balanced TRS stereo pair -> HR824 Left and Right ->THE ROOM -> Sonarworks calibrated measurement mic -> Good quality XLR cable -> Focusrite Scarlett 2i4 -> REW.
I do have Sonarworks software but it is disengaged. I also have some outboard EQs and things etc but none of them are in the chain.
Can you see anything I might be missing? Or is it possible that this is actually the room response?
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Soundman2020
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Re: Basement Studio with some layout quirks
I graphed that, and although it explains some of the roll off, it doesn't match the actual performance you measured in your room either:I came across this test data which seems to indicate that the stated specs for the Monoprice 60599 may not actually match performance
It doesn't match. The "predicted" graph is what I'd expect, more or less. Note that it's not log scale in that one, but I couldn't get Excel to do a log scale with divisions every 10 Hz. And it's not a big difference anyway: It still doesn't match.
That looks fine.This is the current signal chain:
But here's the thing: This graph shows the Mackie speaker by itself, then the combined Mackie + sub, across the entire low end and part of the mid range (18 Hz to 500 Hz):
Green is the Mackie alone. Red is Mackie plus sub, scaled down by 6 dB to match the level. As you can see, the sub is doing nothing at all! There's practically no difference there. I don't understand that. It makes no sense that adding a sub into the room accomplishes exactly zero, and doesn't add ANY low end extension at all! It still cuts off exactly the same, which makes me think there's some filtering going on some place.
I would try skipping the Presonus Central Station: Just go direct from the Focusrite to the sub. I can't see why the Central Station would do anything to the signal, since it's a passive device, but it's the only thing in there that you don't need for the test.
It's POSSIBLE ... if you have some major bass trapping going on at the rear of the room, or no rear wall at all. But unlikely for a small empty room.Or is it possible that this is actually the room response?
Do you have a different audio interface? Do you have other speakers? Do you have another mic, even if it is not a measurement mic? Hell, I'd even settle for seeing tests done with an SM-58, just to see if there's any difference!
- Stuart .