Dog + Bear Studio build

[Soundman2020]

I was really trying to stick with the 38% on this as I didn't want to get pushed to far back in the room,

That's good, but there's no reason to go overboard with 38%. It isn't written in stone. It is often referred to as a "rule" but maybe "rule of thumb" would be more appropriate. Just a general guideline, a point of reference, a good place to start from. You won't be arrested by the 38% Police if you happen to end up at 41% or 35%, or something else. 38% is just the theoretical point at which the modal effects are minimum, but it doesn't change much if you move a few points forwards or backwards.

Also, don't forget that the sofffits themselves change the room geometry, and push the acoustic front wall backward into the room. so your 38% also moves backwards with that.

Maybe try bringing those speakers a bit closer together, and adjusting the toe-in angle outwards a bit.

- Stuart -

[stevev]

cheers Stuart

I went back in there today to run over couple of the points that RJ brought up abut doing some sweeps and listening for holes. None were apparent, although when I was playing a drum track and paying close attention to the panning, it did seem like the overheads had lost a bit of correlation.

I then moved everything in to an equilateral position as suggested and played the same track. The correlation was lot better and the center of the mix was more definite. I've got to say I quite enjoyed listening to the 'wider' mix, although as a day to day working proposition i think you're both right and i'll tighten it up to an equilateral spacing.

At the moment that put's the focal point at 45% room length. I could probably get that down to around 41% with a bit more tweaking, but I probably wont get much lower than that. Does 45% sound like it's getting to far out?

[RJHollins]

cheers Stuart

I went back in there today to run over couple of the points that RJ brought up abut doing some sweeps and listening for holes. None were apparent, although when I was playing a drum track and paying close attention to the panning, it did seem like the overheads had lost a bit of correlation.

I then moved everything in to an equilateral position as suggested and played the same track. The correlation was lot better and the center of the mix was more definite. I've got to say I quite enjoyed listening to the 'wider' mix, although as a day to day working proposition i think you're both right and i'll tighten it up to an equilateral spacing.

At the moment that put's the focal point at 45% room length. I could probably get that down to around 41% with a bit more tweaking, but I probably wont get much lower than that. Does 45% sound like it's getting to far out?

Hi Stevev,

Hey ... glad you ran some testing for your own self ... this way you hear for yourself !

To relay what positioning I have with my monitors [currently]:

A diagram would possibly be easier to convey, but I'll try to verbally describe it ... wish me luck

We've always heard that speakers should be in an equilateral triangle, with the tweeters aimed at the listener's ear [or back of the head]. My experience, working large scale consoles was that much of the time was spent leaning into this 'focus'.

Now in the DAW world, there is little need to stretch 2 or 3 feet to reach trims or EQ's ... and another [as suggested by Gullfo - and others] was to toe out the monitors so that the 'focus' was anywhere from 6" to 24" deeper into the room.

In other words ... 1st establish your equilateral setup. Once in position, keeping the same distance between the monitors, toe them OUT so that the 'point of focus' is behind the listeners head.

Currently, I have mine focused 16 inches behind the original equilateral point.

I used a microphone stand with white paper wrapped around the tubing, with a 'plumb bob' hanging to the floor. On top of my monitor, I centered a squared Laser that I positioned aligned to the center point of the tweeter squared to the cabinet. The laser beam could then be aimed at the center of the mic stand positioned at the exact distance.

Both monitors where aligned this way.

I learned long ago just how difficult it turned out, to critical place an object in a real 3-dimensional space, that were centered at an exact distance apart, precisely aimed, AND symmetrically placed within the wall boundaries.

I also printed out a HUGE protractor template that could be taped to the floor, along with other tape markers positioned on the floor, combined with the laser, allowed me to do this much more accurately. [Oh yeah ... I THOUGHT I had done good with a tape measurer, string, and a protractor] However, the laser [which I had from the construction phase] proved to be invaluable. It again came in handy when I replaced my isolation gummy gels under the monitors. I could pinpoint the aim rather easily. It will also make experimenting with different focal points much easier and predictable.

Some may say that I may be going too far in this alignment process ... but ... when the room and the treatment yield such a level of sonic 'Control', the criticalness of being able to [basically] 'Time Align' your monitors and minimize phase aberrations will influence every sonic decision that will be made. So yeah ... I think it worth the extra effort.

Sorry for the long winded post ... hope something in there is useful

[stevev]

Sorry for the long winded post ... hope something in there is useful

I'm all for the long winded post RJ

monitor angle.jpg

Just so I'm understanding you correctly about the focal point here: Your monitors and your ears/head are forming an equilateral triangle with the monitors as far as distance is concerned, but the monitors are actually aimed to 'intersect' 16 inches behind you. Effectively making an isosceles triangle between the monitors and the focal point (although probably not much of an isosceles triangle) Have I got that right?

I'll also be using the laser trick for lining up the monitor position. The unit I have for construction work will shoot square and plumb to within 5mm at 30meters distance, so I should be able to get them lined up pretty spot on. Glad to hear someone else has taken the alignment process down to the last millimeter as well

[RJHollins]

I knew a diagram would have been easier

You have it exactly as I tried to explain

I'd be interested in your findings too !

Sincerely.

[stevev]

glad we're on the same page there RJ

I'll be pretty busy for the next week or so, but after that it'll be back in to the build. really looking forward to having this baby up and running as there's already work waiting for it to be completed

[Soundman2020]

I know that's just a rough diagram, not to scale, etc., but there are two rather important points that need clarifying.

1) Those speakers are too far into the corners. They should be something more like 30% to 40% of the room width. (There is an "exact" percentage somewhere that is supposed to the "perfect" position, but I can't find it off hand: But take it with a grain of salt anyway: it is like the famous "38% rule").

You could fix that on the diagram by making the rectangle that represents the room a bit wider.

2) The yellow triangle is incorrect, except for people who have their ears positioned in their eye-sockets.. Since most people have their ears poking out the sides of their heads, that's where the speakers should be aimed. Thus, even for the "standard" equilateral triangle, the intersect point will be a few inches behind the head, not inside the head. That's a very common incorrect representation, found all over the internet and even seen in some supposedly expert magazines and books, so don't feel bad about it!

In other words, the second triangle (not the yellow one) is correct for the NORMAL representation of speaker geometry with a 60° intersect, so the "wider" geometry that RJ is talking about would be another triangle where the acoustic axes run a couple of inches outside of the ears, and meet even further back behind the head.

So you could fix that diagram by moving the circle-head forward until the edges of the yellow triangle are tangential to the circle.

Just thought that needed clarification.

- Stuart -

[stevev]

Stuart, your attention to detail is to be respected

monitor angle.jpg

does this look more like it?

Those speakers are too far into the corners. They should be something more like 30% to 40% of the room width. (There is an "exact" percentage somewhere that is supposed to the "perfect" position, but I can't find it off hand: But take it with a grain of salt anyway: it is like the famous "38% rule").

Even though that first diagram was a rough drawing, I'm still glad you brought up this point. I've done a fair bit of reading through this site and through others and I don't believe i've come across this information before.

[stevev]

monitors 60 degree photo.jpg

monitor position 20% room width and equlateral.jpg

the photo above and the diagram is my actual room to scale as I have it marked out at the moment. The front and center of the monitors end up about 900mm from the side wall, and the equilateral triangle is about 2400mm per side. Putting the listening position at about 42% room length.

monitor position 30% room width and equlateral.jpg

If i were to change the monitor distance from the side wall to 30% of the room width I end up with something that looks like this, wth the equilateral triangle at around 1650mm per side. Listening position also ends up around 30% of the room length.


the room is 4200mm wide and 5800mm long by the way. Any thoughts on which is the better of the two setup's?

[Soundman2020]

Stuart, your attention to detail is to be respected

My wife calls that skill "nit-picking", and believe me, I don't get much respect for it!

does this look more like it?

Yup!

OK, I found the number: supposedly the "best" position is 27.7% of room width. Or 29%. Or 32%. depending on who you believe...

Personally, I'd split the difference and call it 28%.

But please do not take that as a "written in stone" rule that must be complied with, and don't go nuts trying to finesse the location of your speakers down to the nearest thou!!! Like the infamous "38% rule" it should just be taken as a guideline. Start there and play around as needed to improve things.


- Stuart -

[stevev]

Personally, I'd split the difference and call it 28%

I'm around 20% at the moment, so if I bring them in closer I wouldn't be surprised if that brings the listening position to around 38% as well. Hopefully i'll get a chance to mark that out in the room and have a listen before too long.

[RJHollins]

Hi Stuart !

Thanks for spotting the details and the correction !!!

Tell the wifey that we love your nitpickin' over here

[stevev]

whilst there is a bit of down time on the build to attend to other things like my 'day-job', I thought I'd do a bit of research on window construction for between the live/control rooms.

So far I have this:

glass density is around 3 times plasterboard. my plasterboard is 32mm thick, so I need glass at least 10.7mm thick. So lets say 11mm or 12mm.

As there is no insulation between the window cavity, the cavity space needs to be at least 1.4 times that of the walls.

The glass panes do not need to be angled to each other.

Each pane needs to be sealed air-tight.



I've got a couple of questions about some other details.

One, do the panes need to be a different thickness?

Two, if a different thickness is required then how much of difference is needed?

[Soundman2020]

You seem to be on the right track with those points. Just a couple of additional tid-bits to add:

As there is no insulation between the window cavity, the cavity space needs to be at least 1.4 times that of the walls.

Or you could make the glass a bit thicker, to add more mass, which would also help. It might not be that easy to make the air gap bigger, depending on the how the wall is built, so increasing the glass mass is another option for compensating for the lack of insulation. Also, there will be SOME insulation: around the edges of the glass, and that does actually have an effect, so the "1.4 rule" is probably a bit of overkill.

The glass panes do not need to be angled to each other.

Correct. At least, they don't need to be angled for acoustic reasons, but you still might need to put a slight angle on to reduce lighting glare, or to design the lighting very carefully such that glare is not a problem.

One, do the panes need to be a different thickness?

It helps, yes, if can, since it means the coincidence dips on the two sides will be at different frequencies. It isn't life-or-death though, so if you can't do that, then just make them both as thick as you can afford.

Two, if a different thickness is required then how much of difference is needed?

Whatever is available in your area! For example, you have figured that you need at least 11mm glass theoretically, so if you find that you can get 12.5 mm and 15mmm that would be excellent, or so would two of 12.5, or maybe even one of 11 and one of 13, but it would not be worth it to go with one of 14 and one of 14.5, for example. The greater the difference in thickness, the better it will be, but also the more expensive it will be. So just look at what is available at a good price in your area, and get the two thickest ones you can afford that are close to your calculations.

- Stuart -

[stevev]

Thanks for the input there Stuart, much appreciated as always

It might not be that easy to make the air gap bigger, depending on the how the wall is built....

The cavity is 220mm and the walls are both inside-out construction on 90mm studs. I'll be able to hang the panes on the inside (room-side) of both walls which gives me a 400mm air gap. Hopefully that means i'll be able to use an 11mm or 12mm glass to keep the cost down a bit