acoustik room treatment - how big are your db - differences?

[Grappadura]

I just realized that between 105 hz and 120 hz the levels vary 15 db in my room. When I mix, I do very fine adjustments to the levels, sometimes only 1 db.

If you don´t have a specialized metering device (whats the name again?) you can test that by putting a mike into the listening position and sweep a sine wave from 20 to 20k hz, you can do that with operator for instance, and record the monitors output. then use spectrum analyzer over the waveform.

the result was shocking... how can I mix down like that.

how much would it cost me to flatten that out? I remember one forum member who posted specs about this and about the room treatment, what was his name again?

[Tone Deft]

SPL meter (sound pressure level)

it's mic not Mike (stupid nitpicky point)

you also have to take into account the frequency response of your microphone.

FWIW I use the tone generator in options-preferences-audio.

learn how your system sounds (props for what you're doing) and understand that your mix is too quiet in the between 105 and 120Hz. double check that you're not having problems with 57.5 and 110Hz and that the 105 and 120Hz artifacts aren't just harmonics of the real problem.

[Grappadura]

ah, thx tone! yeah right, that spike is probably all over its partials haha what a cool sentence. so how big are the level differences at your place? did u treat your room?

[Tone Deft]

I have a bump around 120Hz. I didn't use an SPL meter, just my ears. one afternoon I swept the tone generator around and had a WTF?!?!? moment.

no treatment other than foam under the monitors which made a HUGE difference. I have deep carpeting and a futon that helps to absorb sound. I don't have any complaints about the sound so I don't bug about it. if the bump is bugging me I put a small notch EQ on my Master out. it might be a 60Hz signal because I don't always hear it on TV programs, just some of them. I did take studio pics I've just been too damn lazy to post them.

[Grappadura]

whats the function of the foam? I got a bluesky mediadesk 2.1 system, the subwoofer is on its spikes, and the satellites are on top of some books that I placed there in order to have them on ear level.

Carpet is a good idea, that shouldnt be too costy, plus now I got an excuse for getting a real fluffy one

[timothyallan]

I just realized that between 105 hz and 120 hz the levels vary 15 db in my room. When I mix, I do very fine adjustments to the levels, sometimes only 1 db.

If you don´t have a specialized metering device (whats the name again?) you can test that by putting a mike into the listening position and sweep a sine wave from 20 to 20k hz, you can do that with operator for instance, and record the monitors output. then use spectrum analyzer over the waveform.

the result was shocking... how can I mix down like that.

how much would it cost me to flatten that out? I remember one forum member who posted specs about this and about the room treatment, what was his name again?

me?

http://www.timothyallan.com/studio-design/

[Tone Deft]

tim - oh yeah, that was a sick post.

ideal speaker stands are either non-existent as if the monitor is floating in the air or ROCK SOLID as if the speaker was glued down to a million ton granite boulder.

sound is pressure waves in the air.

the pressure waves are the driver pushing on the air.

the driver pushes against the cone.
break it down, what happens when a monitor produces sound?

pressure waves hit your ears, your brain interprets this is as sound. those pressure waves are made from the monitor's cone pushing air. the cone pushes against the speaker's cabinet. the cabinet pushes against whatever it's resting on.

if your monitor was magically floating in the air, the speaker's sound isn't influenced by what it's sitting on. but it has nothing to push against so you lose some bass, just turn the bass up. you get less bass but a more linear frequency response.

sitting on a solid surface the monitor can push more easily against the air. you get lots of bass and might have to turn it down.

anything in between results in non-linear speaker response. it's unpredictable.


when I brought my Adams home they sounded like shit, the low end was muddy and far from clear. I have them sitting on a wooden desk shelf that's only connected to the desk on one end (it's a 'wing' style shelf.) I was pissed, I called Adam. they said to put down some Auralex, it made a HUGE difference.

try putting your sub on its side so it's not on the spikes, you'll get way more bass out of it. I guess the manufacturer is going more for the floating method.

hope that makes sense.

[Grappadura]

@timothy: Yes you!!! thx!

[Grappadura]

hey tone, thx again for all that wisdom

[Grappadura]

hey timothy, just checking out that frequency response curve. your 50 hz region is about 15 db quieter than the 150 hz region. I guess thats nothing to worry about, as long as there are no bumps? In an ideal situation, would it all be flat, or would there also be this kind of transition?

[nathannn]

I just realized that between 105 hz and 120 hz the levels vary 15 db in my room. When I mix, I do very fine adjustments to the levels, sometimes only 1 db.

If you don´t have a specialized metering device (whats the name again?) you can test that by putting a mike into the listening position and sweep a sine wave from 20 to 20k hz, you can do that with operator for instance, and record the monitors output. then use spectrum analyzer over the waveform.?

do you have to use a special mic for this?

i know my mic is not completely flat and it seems like it would effect the frequency response.
also i get massive feedback when placing my mic near my monitors.

[nathannn]

I have a bump around 120Hz. if the bump is bugging me I put a small notch EQ on my Master out.

I read this on the real traps site:

Another common misconception is that equalization can be used to counter the effects of acoustic problems. But since every location in the room responds differently, no single EQ curve can give a flat response everywhere. Over a physical span of just a few inches the frequency response can vary significantly. Even if you aim to correct the response only where you sit, there's a bigger problem: It's impossible to counter very large cancellations. If acoustic interference causes a 25 dB dip at 60 Hz, adding that much boost with an equalizer to compensate will reduce the available volume (headroom) by the same amount. Such an extreme boost will increase low frequency distortion in the loudspeakers too. And at other room locations where 60 Hz is already too loud, applying EQ boost will make the problem much worse. Even if EQ could successfully raise a null, the large high-Q boost needed will create electrical ringing at that frequency. Likewise, EQ cut to reduce a peak will not reduce the peak's acoustic ringing. EQ cannot always help at higher frequencies either. If a room has ringing tones that continue after the sound source stops, EQ might make the ringing a little softer but it will still be present. However, equalization can help a little to tame low frequency peaks (only) caused by natural room resonance, as opposed to peaks and nulls due to acoustic interference, if used in moderation

[Tone Deft]

^ that's good advice, fix the root cause of a problem, don't just bandage it up.

the one thing about that advice is that we sit in one spot to monitor. the monitors we use are called near-field monitors because they're meant to sound amazing when you sit in front of them, hence the name near-field. IMO they left their advice wide open to sell more foam but you are making me feel guilty for not having some foam up on the walls.

I just realized that between 105 hz and 120 hz the levels vary 15 db in my room. When I mix, I do very fine adjustments to the levels, sometimes only 1 db.

If you don´t have a specialized metering device (whats the name again?) you can test that by putting a mike into the listening position and sweep a sine wave from 20 to 20k hz, you can do that with operator for instance, and record the monitors output. then use spectrum analyzer over the waveform.?

do you have to use a special mic for this?

AFAIK mics are pretty flat, most will work but it's something to consider. when I've asked people about it I just get a 'meh' answer.

i know my mic is not completely flat and it seems like it would effect the frequency response.
also i get massive feedback when placing my mic near my monitors.

OUCH!!!
turn track monitoring OFF for the mic track. if your sound card has direct monitoring use its software interface to turn off monitoring there as well.

[tlennon]

Not only the articles on Real Traps but Ethan has a whole series of videos that explain things very well.

[djsynchro]

how much would it cost me to flatten that out?

$267.35 excluding shipping & taxes per corner. We also do funky patterns for a little extra. current favourite is "Prince and the revolution" rain purple.
We guarantee down to 23.5 Hz