Studio building 103 - flutter and life

[pure.fusion]

Hi all.

Just finished the initial treating of my room (https://homerecording.com/bbs/showthread.php?t=299984) and ended up with a great result. A more linear responce and better stereo imaging, leading to more accurate mixing and a portable mix.

Two things I want to address next is the flutter and the deadness.

Clapping gets me a flutter/echo that I assume if from the rear wall (the one *not* pictured) which is brick and very reflective.

I'm thinking a large diffuser on the rear wall - it won't make the room any more "dead" and the flutter will dissapear hopefully. May have to treat the sides as well, yeah?

As to what sort of diffuser, hmmmm there's a few styles around. I hjave to choose the DIY one.....

Any thoughts from you guys while I ponder the next bit?

Cheers,

FM

 

[pure.fusion]

Man, already this is looking like a ball breaker!

I want to stop the flutter in a non-deadening way and when I look into diffusers, it gets very mathamatical very quickly. Different types designed to be used for a different frequency ranges, calculators, the whole bit.

I really need some direction here......

FM

 

[witzendoz]

Hi,

You will need to treat at least part of the brick walls as brick is notrous for ping and ring. If the room sounds too dead try putting some thin wood panels (Masonite or hardboard) on top of the carpet under where you are recording. Another trick is to put a plastic carpet protector under the chair at the mix position, you get them from office suppliers, it also protects the carpet and makes the chair eaiser to roll.

I would make up a defuser for the other wall (I like defusers) a simple bookshelf with books,CD's and other junk in it will work as a defuser, also helps put these books somewhere.

Cheers
Alan.

 

[pure.fusion]

Books? but I'm not that intellectual?

.. and yes for the floor panels. I was going to get some cheap 6mm MDF sheets and lay them down to see the difference. I'm recording some singing and some trumpet soon.

I'll be honest, I was thinking about building something like the wooden diffuser shown below. I like the look, and I can build it. Will it suit my purpose?

Flutter seems to me across the room (the red axis).

Unfortunately, I don't know anything about the wooden panel technically. (How big the squares are, how deep they are, is there a pattern etc) I know from a small amount of googling that yes, these factors are relevant to the diffusion an the frequency it acts on - but I don't know if it's relevant to *me* cause I just want to stop the flutter without making the room sound more dead. I also don't know how much brick area I would have to cover to make it worth while.

I haven't, and probably *won't* measure the response in the room. For my musical purposes, I know that If I mix a song down, and play it on several sound systems, and it sounds in the ball park of how it should - that's good enough. So, if I'm not measuring response, I can't tailor a panel to it.

Will I be disappointed if I built some of these diffusers and hang them?

I really need some advice here.

FM

 

[RawDepth]

There is a diffuser calculator here. http://www.mh-audio.nl/DiffusorCalculator.asp As well as some other calculators.

But putting a diffuser on the rear wall won't do anything to cure flutter between the side walls. The diffuser will only reduce the 1st reflection echo from the rear wall, at the mix position.

You will need to place at least a few thin (1" or 2") panels on the brick side walls. I would not completely cover the walls, just scatter a few smaller panels about, with space in between, to cover perhaps 25-50% of the wall. Start with only a few and add as needed. (i.e., Add a few, do the clap test, add a few more, do the clap test, etc.) Once it is noticeably reduced, call it good enough.

You could possibly be getting a little flutter between that ceiling beam and rear wall as well. Any two parallel surfaces can cause it.

I am surprised that you are investing that much money and work into a studio and not testing the room for problems.

 

[pure.fusion]

Thanks RawDepth. Sounds like good sensible advice. Thanks.

I am surprised that you are investing that much money and work into a studio and not testing the room for problems.

Well, I always thought that testing the room would lead to treatments that do cost more than what I'm willing to spend.

I downloaded a program called "Room EQ Wizard" from some AV forum last week, installed it but haven't got around to making it work, or understanding how it works 'cause I couldn't just fire it up and go straight away - so I put it on the back burner and here we are.

Why, with the bass trapping that I've done, do you think I'd be close to having a "flat" room? (Or however you describe it).

.. I'm really a noob here. And it *is* hard to keep up the motivation when the initial reason for kicking the whole project off has been satisfied - ie I can mix music and it sounds reasonable portable, at least to my ears. Before I started, the sound was a joke!

Have I got a large task ahead of me for room testing?

FM

 

[jhbrandt]

FM,

You have some nice traps there. You could also use some polys on the brick walls to break up the echo. - and alternate the panels on the brick walls so that the panel on one wall faces brick on the other side and so forth.

Never let untreated surfaces face each other. Learn to use REW - you'll be glad you did.
Cheers,
John

 

[jhbrandt]

There is a diffuser calculator here. http://www.mh-audio.nl/DiffusorCalculator.asp As well as some other calculators.

NOT a good calculator. I would not recommend building one of these. It is based on prime 7 and has too many repeats which will cause specular lobing.

-- In other words when you repeat a sequence too many times with a diffusor, it becomes more like a flat wall again and you get specular reflections.

Just my educated opinion.

Cheers,
John

 

[Weasel9992]

FM,

You have some nice traps there. You could also use some polys on the brick walls to break up the echo. - and alternate the panels on the brick walls so that the panel on one wall faces brick on the other side and so forth.

Great advice from John, as usual. Those long brick walls are your issue. You can solve the problem with diffusion, but it's going to be more difficult and/or expensive to do it that way. Poly-cylindrical diffusers would be a great solution to that problem.

Frank

 

[tmix]

I have a ton more absorbers on the walls and ceiling than you do and it is nowhere near sounding dead.
I have no flutter or ping and can get a a small amount of usable abmbience putting up mics about 20 to 30 feet away from the performers. I track live drums in there too so any bad echos would show instantly.

I guess what I am saying is you probably could cover a lot more of that brick without it fear of the room being dead.
I have stained concrete floor thought where as yuo have carpet.

 

[witzendoz]

A simple defuser is a curved thin wooden panel with some fluffy insulation behind, works wonders for scattering the high frequencies without making the room sound dead. Go to my link name and check out "about the studio" "Recording room" there is a photo there.

I have a home made defuser on the back wall of the control room but it does not show up in the photos.

Check out this site http://www.ethanwiner.com/acoustics.html for lots of information, thanks to Ethan.

Cheers
Alan.

 

[pure.fusion]

Right......

witzendoz: Yup. Ethan's articles are printed out and are sitting next to my keyboard here dog-eared with highlighter marks, pencil sketches and coffee stains.

RawDepth and jhbrandt - Ok, ok. I'll learn the software and measure the room. It couldn't hurt right? Apart from pointing out to me that audiophile nirvana is miles away and financially unachievable, or the only way to kill the problem frequencies in my room is to suspend from the ceiling a 1/8th replica of a 1952 Panzer tank carved out of butter

Let me guess, I have to buy a SPL meter, right?

Thanks all for your input. Probably see you in the Room Eq Wizard forum.

FM

 

[RawDepth]

...Well, I always thought that testing the room would lead to treatments that do cost more than what I'm willing to spend.

Have I got a large task ahead of me for room testing?

No, not necessarily. You already have 80% of the work done. Testing can sometimes reveal a few other problems that can be easily cured with one or two more well placed panels.

You can never get any room to be perfect. But you can continue to tweak, tighten, and tune until your mixes become easy to do. That is, with a better room, your mixes will sound closer to being correct on the first try. It will lead to less wasted time doing mix tweaks to get them to translate.

Testing can reveal if you have a standing wave at a certain frequency, or perhaps ringing of some sort. Mostly little things that you may not notice with ears alone.

It will likely lead to improved imaging for panning, better judgment of spacial and time based effects, and more overall truth at the mix position.

...it *is* hard to keep up the motivation when the initial reason for kicking the whole project off has been satisfied - ie I can mix music and it sounds reasonable portable, at least to my ears. Before I started, the sound was a joke!

You don't have to improve the room any further if you don't want. If you are happy, then you have accomplished your goal.

Many of us are perfectionists. And it is our sworn duty to push all newbies toward perfection as well. If you let us, we will suggest that you spend a million dollars more on the room.

Really, only you can decide when the room is done.

 

[pure.fusion]

Well, I spent about 30 mins with oom EQ Wizard tonight.

I got it to make noise. I hooked up my condenser mic and got it to measure *something*. I just need to sort out th finer details and I'll get a measurement - it shouldn't be too hard.

I cannot see how I can can callibrate without a SPL meter though - this is going to suck. I'll be looking at divorce if I said I'm going to buy a SPL for a one off measurement

More reading needed....

Having done this and being at this stage, I see where you're at Rawdepth. It is a bit silly not to test the room having come this far.

FM

 

[Weasel9992]

I got it to make noise. I hooked up my condenser mic and got it to measure *something*. I just need to sort out th finer details and I'll get a measurement - it shouldn't be too hard.

There's an SPL meter in REW...you use it to establish a base line dB level. You could use an SPL meter to make sure the one in REW is accurate, but it's not really necessary.

Frank

 

[pure.fusion]

There's an SPL meter in REW...you use it to establish a base line dB level. You could use an SPL meter to make sure the one in REW is accurate, but it's not really necessary.

Frank

Perfect! That's the info I was after. Thanks Frank.

FM

 

[jhbrandt]

FM,

There are some great tips on using measurement software here. Good luck!

Cheers,
John

 

[Weasel9992]

Perfect! That's the info I was after. Thanks Frank.

FM

Not a problem. REW isn't all that intuitive...it takes some practice, but once you get the hang of it you'll realize that it's a pretty great program.

Frank