Help room setup

[Rangler]

I have the monitors (LSR 305) spaced about a yard in a triangle, but where I sit, I can't hear any bass (the blue X), but I can hear perfect bass about 6 feet back (the red X).

I'm planning on building some Corning 703, but they won't effect the bass, from what I'm told.

[BenK-msx]

Is your sweet spot at around 37% into the room? (~5.ft from front)

Corners will need absorbers, thick.. else the lows that are bouncing around the room and effecting what you hear won't be absorbed.

Rear wall too plus a diffuser/scatterer ideally (once you have absorbtion)

First reflection points to sides of speakers too, that requires less hefty treatment. Ceiling perhaps too.

It's all there on the Google machine, just a matter of what you can afford to do.

Id Prioritise corners for bass 1st reflections for accuracy.

[Rangler]

Originally Posted by BenK-msx

Is your sweet spot at around 37% into the room? (~5.ft from front)

Corners will need absorbers, thick.. else the lows that are bouncing around the room and effecting what you hear won't be absorbed.

Rear wall too plus a diffuser/scatterer ideally (once you have absorbtion)

First reflection points to sides of speakers too, that requires less hefty treatment. Ceiling perhaps too.

It's all there on the Google machine, just a matter of what you can afford to do.

Id Prioritise corners for bass 1st reflections for accuracy.

The bass sounds best at the red X on the drawing.

[BenK-msx]

Yeh that isn't the point you want it best at your sweet spot...
'Best' reflecting off the rear wall isn't necessarily 'best for mixing' either btw.

It is suggested that the blue X be 37-38%% into the room, I was checking if that's the case.

This reduces chances of bad room modes a bit, then by treating corners with thick absorbtion, so that they absorb the lowest frequencies, should reduce low frequency modes more and reveal accurate bass in the sweet spot.


The problem you experience is bass freqs bouncing around the room like crazy interfering with each other and creating areas of low bass (nulls) and areas of high (peaks) all slightly delayed compared to the source, leaving a bass sound that is innacurate & fills the room in a bad way rather than feeling like it comes from your speakers to your ear direct.

This makes mixing the low end accurately so that it translates to all systems extremely difficult.

[Rangler]

Originally Posted by BenK-msx

Yeh that isn't the point you want it best at your sweet spot...
'Best' reflecting off the rear wall isn't necessarily 'best for mixing' either btw.

It is suggested that the blue X be 37-38%% into the room, I was checking if that's the case.

This reduces chances of bad room modes a bit, then by treating corners with thick absorbtion, so that they absorb the lowest frequencies, should reduce low frequency modes more and reveal accurate bass in the sweet spot.


The problem you experience is bass freqs bouncing around the room like crazy interfering with each other and creating areas of low bass (nulls) and areas of high (peaks) all slightly delayed compared to the source, leaving a bass sound that is innacurate & fills the room in a bad way rather than feeling like it comes from your speakers to your ear direct.

This makes mixing the low end accurately so that it translates to all systems extremely difficult.

I wish there was a way to visualize where the bass is bouncing around. Treating the corners seems so unintuitive and pretty expensive, especially since I don't own the place.

[BenK-msx]

am afraid some reading could be in your future!

its just the nature of a corner means physically the freqs build up there as they pile on top of each other. so is best place to hoover them up with an absorber.

the physics gets crazy very quickly - minefield, but big gains can be had with the basic things mentioned.

heres my latest analogy to help grasp how nuts acoustics gets and how quickly - bear with me! :

------------------

Think of each of your speakers as cartoon style bombs that explode -
bowling balls, footballs, basketballs, tennis balls, ping pong balls and little rubber balls in *all* directions (the ping pong and rubber balls fly pretty straight out of the front however) - at the speed of sound.

picture these objects exploding out from your speakers unpredictably bouncing off every surface in your room like some horrific 3D pool break-off, colliding into each other, ( growing or shrinking as they do ) & imagine how some of them stop flying around sooner than others (the smaller stuff) and how different surfaces in your room affect how the objects react.

the big ones want to bounce around for what seems like forever, the little stuff loses mojo quicker.

Corner absorber/traps are there to stop the big bowling balls, basketballs, footballs etc. (bass frequencies) that would cause mayhem in the room if unchecked.
as soon as they encounter the trap - they vanish (in a magic perfect trap )

smaller absorbers only gobble up the tennis balls and smaller stuff (higher frequencies)

diffusers - rather than gobble up - they scatter/reflect the small stuff (higher freqs) in all directions so they disperse and don't get back to your ears too soon or too strong to interfere with the direct sound.

to finish - imagine your job as mixer is to track how many & what type of balls emerge directly when these bombs go off, so that it sounds right in any room.

if things are smacking you in the head from all directions and clattering into each other and changing size its easy to lose track and make a wrong decision, leading to it sucking in another space.

BOOM!! crazy analogy over!!

--------


btw easy way that springs to mind is you know those big rolls of loft insulation you can get at diy shop? - shove them ( in their wrapper) in the corners.

should be large improvement compared to nothing.

[Rangler]

Originally Posted by BenK-msx

btw easy way that springs to mind is you know those big rolls of loft insulation you can get at diy shop? - shove them ( in their wrapper) in the corners.

should be large improvement compared to nothing.

Very informative. There are 8 tri-corners and 8 bi-corners. Which would you start at?

I also might go the sonarworks headphone route

[BenK-msx]

for simplicity - the vertical corners behind your speakers - then rear. so basically the corners of your floor plan.
often a door hinders doing all corners but whatever you can.
wall ceiling corners -

consult web for a heap of more accurate info.

recall my first big trap 10 + yrs ago. placed over one corner - that was rockwool slabs in their wrapper. they are prob more effective than loft stuff as is dense. (those rolls as tightly packed can be dense tho) - clue: if its heavy to pick up whilst being loose/airy - thats a good sign.

killed 90hz peak i had in a small space no problem.

my new space needed a shed load of treatment recently, went the tube trap route for space and convenience reasons (rockwool cylinders + sealed with wooden lids.) i think they work!

[Rangler]

Originally Posted by BenK-msx

for simplicity - the vertical corners behind your speakers - then rear. so basically the corners of your floor plan.
often a door hinders doing all corners but whatever you can.
wall ceiling corners -

consult web for a heap of more accurate info.

recall my first big trap 10 + yrs ago. placed over one corner - that was rockwool slabs in their wrapper. they are prob more effective than loft stuff as is dense. (those rolls as tightly packed can be dense tho) - clue: if its heavy to pick up whilst being loose/airy - thats a good sign.

killed 90hz peak i had in a small space no problem.

my new space needed a shed load of treatment recently, went the tube trap route for space and convenience reasons (rockwool cylinders + sealed with wooden lids.) i think they work!

Hey thanks for your time and knowledge! I really appreciate it.

[cyrano]

Originally Posted by BenK-msx

It is suggested that the blue X be 37-38%% into the room, I was checking if that's the case.

By whom?

It all depends on the room. And you can't judge that from a drawing. There's a third dimension to worry about, fi.

The same with the much touted triangle. It's not ideal at all. Just consider some speakers having a rear bass reflex port and others that could be ideally mounted IN the wall. Mounting in the wall gives a bass extension and that will mean less power to the speaker for a given SPL. Usually translating into less distortion and more headroom after eq.

This reduces chances of bad room modes a bit, then by treating corners with thick absorbtion, so that they absorb the lowest frequencies, should reduce low frequency modes more and reveal accurate bass in the sweet spot.


The problem you experience is bass freqs bouncing around the room like crazy interfering with each other and creating areas of low bass (nulls) and areas of high (peaks) all slightly delayed compared to the source, leaving a bass sound that is innacurate & fills the room in a bad way rather than feeling like it comes from your speakers to your ear direct.

This makes mixing the low end accurately so that it translates to all systems extremely difficult.

Corners aren't your first worry. Large, flat, reflective surfaces are. And if you dampen those large surfaces, you can worry about corners.

[BenK-msx]

Originally Posted by cyrano

By whom?

It all depends on the room. And you can't judge that from a drawing. There's a third dimension to worry about, fi.

The same with the much touted triangle. It's not ideal at all. Just consider some speakers having a rear bass reflex port and others that could be ideally mounted IN the wall. Mounting in the wall gives a bass extension and that will mean less power to the speaker for a given SPL. Usually translating into less distortion and more headroom after eq.



Corners aren't your first worry. Large, flat, reflective surfaces are. And if you dampen those large surfaces, you can worry about corners.

For bass specifically and where to put your largest thickest treatment, corners just make sense - alongside medium treatment @ reflection points imo

And as a starting position the 38% position guide has a slightly higher chance of reducing modes at listening point but of course isn't a universal truth.

It doesn't appear he is going to soffit mount or any of that jazz so am trying to helpful.

Its Simple advice for an easy way to improve bass response, not really an opportunity to get too nitpicky.

Or do we suggest OP gets his measurement mic out and study waterfall plots, after inputting every mm of his room into a calculator?

Rather than argue with me, help the bro out!

A thread where technogremlin described his room improvements and approach that could be handy is here btw

https://forum.cockos.com/showthread.php?t=153646&

[cyrano]

Originally Posted by BenK-msx

Or do we suggest OP gets his measurement mic out and study waterfall plots, after inputting every mm of his room into a calculator?

Yes. Measurements are necessary, imho. REW is free, an ECM8000 is 60$. It's the only way to gain some insight into the problem. Unless you're counting on placebo effect or sheer luck.

Rather than argue with me, help the bro out!

I've had to correct rooms that were done this way once too often. His problem started with typical advice: place your speakers in an equilateral triangle. That advice is usually wrong to start with.

A thread where technogremlin described his room improvements and approach that could be handy is here btw

https://forum.cockos.com/showthread.php?t=153646&

Sorry, whenever I see people using foam, I quit reading. Foam is useless. Unless you can find a very unusual kind of foam: open cell, high density foam. Even a big plastic supply house has to custom order it and it is expensive, compared to all the stuff sold on the net. That typical pyramid foam, fi.

In this particular case, I can't even tell if Rangler needs absorbers in front or in the back. And the JBL's have large bass reflex ports on the back. If they hadn't I would tell him to place the speakers' back flush to the wall. These are good speakers, but the port is less handy in this case.

If you want to avoid simple measurements at all cost, you'd need to start with moving the speakers and the listening position around in the room. That will also give you and idea, but it will take much more time.

You don't want waterfall plots. A simple frequency graph will do. It takes maybe an hour or two to learn a bit about REW and 5 minutes to make a frequency sweep chart. With that chart, you can SEE what moving the listening position backwards will do. And that leads to the area where the absorbers should be placed. Usually the corners aren't the worse spot, as they don't reflect as much energy as large flat, reflective surfaces.

And that's only absorbers.

Diffusers are a real waste of money without professional, extensive measuring. Especially in a smaller room, like this one. In a large, well tuned room, they might add something. If and only if calculated for that room after about a week of measurements. Still expensive, but worth doing it.

I'd start out with one or two large absorbers. 4 or 5" thick. Mineral wool, Doesn't really matter much which density, as long as it's thick enough. Higher desity is better, but don't exaggerate. Look at the price first.

Make a wooden frame, cover with some nice textile. Don't worry which textile, as long as you can breath easily through it. They will affect bass. Maybe not enough to solve the problem, but certainly enough to hear where the problem comes from.

Move that absorber around. Takes time too, but it's a little more scientific than just throwing expensive corner absorbers around. Start on the wall behind the listener. Maybe you'll need two of those. One for the wall opposite, because of the bass reflex ports. Test corners, don't worry if there is empty space behind your panels.

Keep in mind that walls are easy. The floor and the ceiling are a bit harder to test. But usually it's the walls. And since it's not your place, I guess treating the ceiling is out of the question anyway.

Of course, posting a few graphs would eliminate some experimentation.

Another question is: What's in the room? Is it empty? Any plans on putting stuff in?

If you treat an empty room and fill it up later, with rugs, curtains, a couch, book cases, you'll have to start over again, as the room may just turn out over-dampened. Dead.

What materials are the walls made of? Brick, concrete, gypsum plates... ? Same for the floor. Wood? Concrete?

Also, you can get Rockwool boards. Far easier to work with than rolls. You can even use those (temporary) to test what they do. And by testing, you'll need less of the stuff. It isn't very expensive, but it isn't dirt cheap either.

The major disadvantage in using your ears is that we can't help you with the results. Only you can hear what it sounds like. With a few graphs, we can look over your shoulder...

[BenK-msx]

you can make your point to OP without referencing me,
everything prior to
'in this particular case...' is arguing with an imaginary me who disagrees with you.
he's not a thing.

didn't mention triangles or foam..

point was that OP doesn't know all this stuff yet, and likely doesn't really need a acoustics lecture 1st off.

clearly research will help out massively as suggested, but there are easy things that would likely tame his bass, now - with intro info.

that thread linked seemed a good one to 'dip your toe', i didn't vet it for the word 'foam', sorry..

[vdubreeze]

Before you get too involved with the rest of the room (though it's important for sure) I would spend some time dealing with the factors you have control over near the desk. The distance from desk to wall and speakers from each other and your head in the chair might be book right but shouldn't be taken too literally. My first thought just from your description and the graphic is that the speakers are likely too far apart to give accurate bass when pointed in in such a way to aim at you in the chair. It makes sense that the coming together of the two isn't lining up where you want it but somewhere else.

I'm not sure any amount of work on the room will move the bass coming together focus from red X to blue X. If it were me I'd bring the speakers in an inch at a time, and get them less angled, more towards the same plane until it improved enough at the intended sweet spot. And then work on the room.

[jerome_oneil]

Originally Posted by cyrano

Yes. Measurements are necessary, imho. REW is free, an ECM8000 is 60$. It's the only way to gain some insight into the problem. Unless you're counting on placebo effect or sheer luck.

I can't agree with this enough. Measuring the room is practically free, will give you objective feedback on what is going on in the room, and is easy to do.

It's where you should start, every time. There is no reason not to.