Fixing Room Acoustics & Monitoring/Mixing

[imdrecordings]

I recently got the TRueRTA progam. I'm getting a lot of +5db in the 100-200hz range as shown the RTA program. Causing my mixes to come out on the bright side. I boosted the high-end and cut the low-end and highpass at 60hz on the back of my Dynaudio BM5As, but still having a bit of build up. So I tried compensating with EQ on the master buss and unload the eq plug at mix down. Sounds pretty good now.

I posted, a wile ago, a thread about how my tracks have been coming out so bright and that I've had to cut a bunch of high-end out of almost everything. Well things haven't changed and I've recently discovered the reason as to possibly why.

I think my desk is resonating or amplifing those lower frequencies. Mopads aren't really doing much. I'm going to try some speaker stands and see what that does, but I'm affraid my desk is so fat that it will put my Monitors, just slighhtly farther than I would like.....

I think I mite be getting some high-end reflection from the desj aswell.

I can't make adjustments to my room or move in a different spot. So I figure I'll buy a Dual 31 band Graphic EQ...just before my monitors.

Is that a bad idea?

oh and another thing...after the adjustment, now i'm getting a big spike at 1khz....wha

 

[Fundy]

I use monitoring stands, as decoupling your monitoring source is just as important as having all the right acoustics in the right places.

 

[imdrecordings]

I use monitoring stands, as decoupling your monitoring source is just as important as having all the right acoustics in the right places.

Yeah, I'm going to try that today... I noticed the difference when I put the monitors on my desk. My desk is pretty sweet and it put the Monitors in the perfect place, but the desk is resonating. I got the Blueprints for this console and built one myself. Out of Particle board.

Of course it doesn't look neary as sleek, but still..
You can see why putting my Speaks on stands maybe a problem. Sense it will be pushing them back a little bit.
We'll see...

 

[boody]

I recently got the TRueRTA progam. I'm getting a lot of +5db in the 100-200hz range as shown the RTA program. Causing my mixes to come out on the bright side.

<snip>

I think my desk is resonating or amplifing those lower frequencies.

Hey, I dunno, but a 5 db boost coming from a resonating desk sounds a bit high. I'm in a not too big control room (5x3,5 meters, asymetrical with a pointed roof) and I know that smaller rooms tend to lead to the trouble you described, specialy when they are treated to diminish reflections. Is the 5db boost constant or is it level dependend? Do you experience different resonances on differentspots in your room? Does you desk have a lot of hollow, (semi)closed spaces that might amplify? Basstraps might be something for you if you haven't got 'm yet.

Sounds interesting, that TrueRta program. I'll google that 8)

cheers
Budy

 

[imdrecordings]

Hey boody,
thanks for the help.
My room is pretty wide, maybe 50 or 60 feet, so no side reflections. I have some heavey Bass trapping behind me, plus a coach. When I place the mic a foot or 2 back from the console the bass build up evens out. Put the mic right over the keyboard/ at the very front of the console (imagine my gorgeous head leaning over my keyboard) 8) and you see the 5db increase, in the lower frequencies. It's weird that such a minor movement can have such a dramatic affect. Also... the big 1khz spike is totally confusing me. I'm going to also reinstall the software. It could be giving me some faulse readings.. hmmmm :?

I'm doing my readings/measurments at 85-90db. With a quick sweep and in 24 octave increments.

Sweet GOD! Does anything above a 1khz test tone hurt at 90db. They should tell you to wear ear plugs when you do this.

 

[boody]

Hey boody,
thanks for the help.
My room is pretty wide, maybe 50 or 60 feet, so no side reflections. I have some heavey Bass trapping behind me, plus a coach. When I place the mic a foot or 2 back from the console the bass build up evens out. Put the mic right over the keyboard/ at the very front of the console (imagine my gorgeous head leaning over my keyboard) 8) and you see the 5db increase, in the lower frequencies. It's weird that such a minor movement can have such a dramatic affect. Also... the big 1khz spike is totally confusing me. I'm going to also reinstall the software. It could be giving me some faulse readings.. hmmmm :?

I'm doing my readings/measurments at 85-90db. With a quick sweep and in 24 octave increments.

Sounds like a nice room 8) No place for a couch behind me... :roll: How much space is there between your desk/speakers and your front wall? Did you try to move the desk with speakers further/closer to the wall to see if the frequency reads out different? Are you sure it's not a phase-problem you have (would explain the 1khz peak but should also deliver a 1khz dip on another spot close to the right or left of it). Same goes for the minor movement when hanging over your desk)

always fun fighting them frequencies :wink:

 

[imdrecordings]

Sounds like a nice room 8) No place for a couch behind me... :roll: How much space is there between your desk/speakers and your front wall? Did you try to move the desk with speakers further/closer to the wall to see if the frequency reads out different? Are you sure it's not a phase-problem you have (would explain the 1khz peak but should also deliver a 1khz dip on another spot close to the right or left of it). Same goes for the minor movement when hanging over your desk)

always fun fighting them frequencies :wink:

True that...

Some great suggestions...

I have a good 15 ft behind my monitors and the same behind me. It's a cool room. A little dead for my taste, but what can you do. Only has 11 foot acoustic tiled sealing. Pretty Dead.

Phasing? hmmm... God I hope not :| I wonder how that could happen. I'm just using one mic?

But there is a big concrete Pillar in front of me,2'x2' wide streching up through the sealing and kind of in the middle of my monitors. Just a bit back from them, but not really in the projection range of the monitors.

 

[boody]

Phasing? hmmm... God I hope not :| I wonder how that could happen. I'm just using one mic?

But there is a big concrete Pillar in front of me,2'x2' wide streching up through the sealing and kind of in the middle of my monitors. Just a bit back from them, but not really in the projection range of the monitors.

phasing of direct signal from your speakers and indirect signal from something reflecting or resonating. No room is phase free, but it should be in limits. That pillar could possibly reflect and cause phase trouble, but there's no way to tell but test it... maybe ty some pillows to it at the height of the speakers...

There's this test where you can 'measure' the acoustic preciseness (is that a word?) of your room and equipment by a computer designed 3 dimensional sound test... gotta check the name (goes searching for book)... ahh, the LEDR test. Maybe you have it, if not, it's another way of testing the system

goodluck with the hunting :wink:

 

[imdrecordings]

Good god! My roommate threw out my Monitor stands...
Bummer :x

 

[boody]

Good god! My roommate threw out my Monitor stands...
Bummer :x

I heard (from extremely reliable source) that the best monitor stands are hollow pillars (of any material) filled with sand... so you best go out and find that shovel :wink:

 

[MASSIVE Mastering]

EQ isn't going to fix the room - If the problem isn't with the speakers themselves, the only way to fix the room is to fix the ROOM.

 

[imdrecordings]

Uh.. right...

But it will help...

Yes?


:|

 

[MASSIVE Mastering]

No, it will not help. That's the point. You can not correct a room with EQ. You can not make a room sound better with EQ.

You *can* tailor *the speakers* to *your* preference with EQ to some extent. But that isn't going to make the listening space more accurate.

If you're getting 5dB peaks (most people would *KILL* for a room that's within 5dB of flat in the low end, so I'd be suspicious of the measurements - unless you have a ridiculous amount of broadband and bass absorption in the room) cutting the lows from the speakers isn't going to solve the problems in the room. That 5dB peak might only be at your left ear. It could easily be a 30dB null at your right.

 

[Dan Duskin]

Fixing a room with EQ is the wrong thing to do... period!!!

Ok... if your room is within +/-4dB of perfectly-flat, you can use EQ, but even then you have to be really fucking careful! And you need to understand that you are not killing the peaks and dips, you are only narrowing the width (Q), and that if you move from the position that you used to RTA and EQ from everything goes to shit!

The only way to fix the response of an existing room is to use treatment... PERIOD!!!

The more fucked up the room, the more important it is to use near-field monitors (the closer the monitors are to you, the less the sound of the room will come into play... however, the room ALWAYS make a big difference, even with monitors 2 feet from your ears!).

Fixing the room is 98% about flattening the bass response!!

To do this...

FIRST:
Put bass traps in the corners (the tri-corners are most important, but all corners matter). And remember that sound doesn't know up from down, left from right, etc.... i.e., the wall-to-wall corners are just as important as the wall-ceiling and wall-floor corners!

SECOND:
Use mathematics to figure out the axial room modes (axial modes are standing waves that are perfectly up-down/left-right/front-back of you). A good place to start is by going to this webpage and put in your room dimensions:
http://www.bobgolds.com/Mode/RoomModes.htm

THRID:
Once you figure out your axial room modes, you can start applying bass traps to the axial locations of your listening position (perfectly up-down/left-right/front-back of you). The frequency of the mode will tell you what kind of bass trap to use and how far to space it from the wall/ceiling (anywhere you put it). Look at the specs of the bass trap to find one that has maximum absorption at the frequency of the mode... then, space it from the wall/ceiling at a perfect 16th/8th of the length of that mode.

FORTH:
Experimentation! This is very important... because all remaining modes are Tangential or Oblique, which are very difficult to trouble-shoot with mathematics. You should have a partner hold a big piece of foam (or a big cloth/cushion) in different locations around you to see which location flattens out any remaining problems the most. I recommend using a sweeping sine-wave for this... but you can also use pink-noise (not as effective, but it's quicker).

FIFTH:
Place a semi-absorbent (not fully absorbent) material at all the first reflection points. To do this, take a small mirror and have a friend move it around each wall (including the ceiling). When you are sitting in the mixing position and you can see a monitor in the mirror, that's where you need to put the semi-absorbent material.

SIXTH:
Not necessary... but many acousticians recommend it. Place diffusers on the back wall (a book-shelf with lots of books will do just fine).

SEVENTH:
Place thick/dense foam (or fiberglass) anywhere that bass can develop and come back out... like, under chairs, under desks, behind chairs/desks, under shelves, etc...

EIGHTH:
Now, and only now can you think about EQ!!! And even now you need to be fucking careful!!!

 

[imdrecordings]

I played with the EQ switches on the back of the BM5As and that seemed to help a bit.
I'll try and get some pix of my room up and show you what I dealing with. I'm thinking that a lot of the weirdness is coming from the cement pilar infront of me and the the desk resonating.

I think maybe foaming/trapping the pilar and pulling the speakers of the desk might help more. For now, the EQ on the back of the monitors, is working well.

Thanks for the tips Dan and everyone... Dan, are those HD650s really that good?

-S-

 

[imdrecordings]

I'm getting close to dialing in the freq, but I'm getting the typical 150-200hz bump in the mix postion. About =5db I moved my desk/spread my monitors apart a little more the mids improved a bit. As I move back from the mix position 100hz takes a nose dive. Weird.. I'm wrestling with this one... :?

 

[imdrecordings]

Taking a trip out to Home Depot to buy some supplies to nip this in the butt...
For anyone interested in Bass traps, Acoustics and such, check this out.
http://www.ethanwiner.com/acoustics.html
This man has some great informartion!
-S-
edit: The Depot doesn't stock this stuff... luckily I got a wonderful, happy woman by the name of Kathy in their Pro Services... she managed to hunt some down for me, for special order..Different manufacturer than Owens. No price tell monday.

 

[MASSIVE Mastering]

That's what I was talking about. I have 25 broadband traps (several of Ethan's RealTraps, stacks of GIK 244's, 242's, and several custom Klups units) in this room.

And I'm not to +/- 5dB...

But the \"nose dive\" at 100Hz is pretty typical (\"nose dives\" in general - The point at which they occur is dependent on the size of the room). You're probably closer to +/- 30 or 35dB in some spots at some frequencies.

Broadband trapping and lots of it. All the time, every time, can't go wrong.

 

[manolito]

also try to check your room with \"Room Wizard\" (free)
http://www.hometheatershack.com/roomeq/

this tool halps me alot to check other rooms I did long time ago, try it, maybe youll like it...

 

[Guest]

Another thing you could try is to do several measurements. Place the mike in several postions and see what happens. In my situation, my sweetspot is not where it is now, but about 50cm behind me. My solution was placing my DynAudio's BM15A on stands (still have to do it though).
Below is a picture of my room.