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Ideal Vocal Room decay time
Old 7th June 2020
  #1
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skiroy's Avatar
Ideal Vocal Room decay time

Hello so unfortunately I have a small vocal room that's just the bedroom that I can't really do much with. I do have Broadband panels up. I'm currently trying to do my best of correcting EQ and mode issues. Just to stay on topic I want to act like this is just my vocal recording room. Why do also record guitars in as well from time to time.

I want to make a so I know somebody's going to ask but I mostly record hip hop vocals and occasional R&B vocals. To me this seems relevant because R&B vocals is more like an instrument whereas hip-hop vocals would be more considered similar to recording rhythmic instruments.

Currently I believe my room is overly dead which is a common rookie mistake. My room is about 11 x 12 x 8. And I do have carpet on the floor which I'm considering pulling out for wood. I guess the concept is being able to add some reflection back without having to remove my Broadband panels.

So the question is what would be the ideal Decay time I would be shooting for being that I'm recording mostly rhythmic style vocals? I don't like the sound of the room sounding completely dead or like an isolation booth. But I also don't want so much Reverb that it's difficult to add it in the mix with plugins later. So my question to everybody is in my situation what would be a good goal to achieve as far as decay time?
Old 8th June 2020
  #2
Quote:
Originally Posted by skiroy View Post

So the question is what would be the ideal Decay time I would be shooting for being that I'm recording mostly rhythmic style vocals? I don't like the sound of the room sounding completely dead or like an isolation booth. But I also don't want so much Reverb that it's difficult to add it in the mix with plugins later. So my question to everybody is in my situation what would be a good goal to achieve as far as decay time?
The ideal decay for a listening room your size is around .2 sec.

.15 sec is acceptable and .1 sec and below sounds like a pair of headphones.

Mind you we are talking across freq from 63hz to around 10khz.

The hardest part to even out in smaller vocal rooms is the bass.
People just stuff the walls with thin insulation which absorbs a ton of the hi's and mids but lets the lower mids and bass just ring out.

My advice for vocal rooms is to trap the ceiling completely and go as deep as you can. I am talking 16" or deeper. Build the light fixtures around the trapping.

Same goes for the wall behind you in terms of treatment. The sidewalls you can do 4" but 8" is best if you can manage.. The front part which in most vocal rooms is a door you can leave untreated if its made of glass or if needed build something around window. Floor is usually exposed wood, cement, tiles, whatever.

Lastly you must figure what to do for ventilation in this room and build around it accordingly.
Old 8th June 2020
  #3
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andrebrito's Avatar
Vocal booths are supposed to be dead since you are adding reverb in your DAW.

Never heard of an ideal decay time for vocal booths, it only applies to other spaces where reverberation actually exists.
Old 3 weeks ago
  #4
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skiroy's Avatar
Quote:
Originally Posted by andrebrito View Post
Vocal booths are supposed to be dead since you are adding reverb in your DAW.

Never heard of an ideal decay time for vocal booths, it only applies to other spaces where reverberation actually exists.
Its a room not a booth. I dont like how a both sounds. To me is more difficult to get to sit in the mix on different projects. Im shooting for something a little more natural but still dead enough to have versatility to add reverb or leave more on dryer side. I think .2-.25 secs is a good balance but right now Im at .14 and its sounds like Im in a box.
Old 3 weeks ago
  #5
Quote:
Originally Posted by skiroy View Post
and its sounds like Im in a box.
That's because you are just absorbing hi's and letting the low mids and lows ring out.

When a room is trapped correctly even at .15 sec, the sound characteristic is more airy and clear sounding i would say and definitely not low mid heavy.
Old 3 weeks ago
  #6
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Quote:
Originally Posted by thethrillfactor View Post
That's because you are just absorbing hi's and letting the low mids and lows ring out.

When a room is trapped correctly even at .15 sec, the sound characteristic is more airy and clear sounding i would say and definitely not low mid heavy.
Exactly.
Considering that the room is relatively small, there can't be too much absorption.
Old 2 weeks ago
  #7
What interesting answers you received!

There are many truths.

In my own work, I have come to some conclusions other than those mentioned so far in the thread.

I cut out a statement from each answer, which you can see in a different way:

”The hardest part to even out in smaller vocal rooms is the bass.”

Well, that may be true, but it is not impossible with right acoustic treatment!

”Vocal booths are supposed to be dead since you are adding reverb in your DAW.”

Current GS standards, mean that small rooms should be acoustically dead.
But it doesn't have to be that way. There are other solutions.
I´m desiging a vocal booth at the moment, it is not a dead room, AND you CAN still add reverb while mixing.

”Considering that the room is relatively small, there can't be too much absorption.”

Well. There we have it again.
Listen to my tiny space I´m building, as a test room, prior to the proper renovation of my own studio.
It is almost no soft absorbers at all.
You can instead use tuned Helmholtz boxes and broadband diffusers with optimized time domain diffusion.

Tiny Closet Space Recording Booth



In my studio I have the same diffusers as gobos, in different material, resonance free aryl, on wheels, which I used for the recording posted below.

You could have these gobos in your room around the walls and build tuned HH boxed yourself below or above them to even out bass problems.
If it is possible to make the small room in my first link to sound great.
It´s possible with your room!



The recording have neither EQ nor compression. Just the sound straight in to mics/pre/AD-converter.
According to myself microphones/placement and the diffusors is working 50/50 here to achieve the pretty good sound,
for being a completely untreated rough mix…

Well, the link is a High End Super Nerd AD shootout.
But it is the rough mix I´m talking about, acting as test sound for my AD-comparison.

AD Converter Comparison Test - Cranesong/Forssell/Prism/RME
Old 1 week ago
  #8
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skiroy's Avatar
Quote:
Originally Posted by Berndalen View Post
What interesting answers you received!

There are many truths.

In my own work, I have come to some conclusions other than those mentioned so far in the thread.

I cut out a statement from each answer, which you can see in a different way:

”The hardest part to even out in smaller vocal rooms is the bass.”

Well, that may be true, but it is not impossible with right acoustic treatment!

”Vocal booths are supposed to be dead since you are adding reverb in your DAW.”

Current GS standards, mean that small rooms should be acoustically dead.
But it doesn't have to be that way. There are other solutions.
I´m desiging a vocal booth at the moment, it is not a dead room, AND you CAN still add reverb while mixing.

”Considering that the room is relatively small, there can't be too much absorption.”

Well. There we have it again.
Listen to my tiny space I´m building, as a test room, prior to the proper renovation of my own studio.
It is almost no soft absorbers at all.
You can instead use tuned Helmholtz boxes and broadband diffusers with optimized time domain diffusion.

Tiny Closet Space Recording Booth



In my studio I have the same diffusers as gobos, in different material, resonance free aryl, on wheels, which I used for the recording posted below.

You could have these gobos in your room around the walls and build tuned HH boxed yourself below or above them to even out bass problems.
If it is possible to make the small room in my first link to sound great.
It´s possible with your room!



The recording have neither EQ nor compression. Just the sound straight in to mics/pre/AD-converter.
According to myself microphones/placement and the diffusors is working 50/50 here to achieve the pretty good sound,
for being a completely untreated rough mix…

Well, the link is a High End Super Nerd AD shootout.
But it is the rough mix I´m talking about, acting as test sound for my AD-comparison.

AD Converter Comparison Test - Cranesong/Forssell/Prism/RME
Wow that sounds mind blowing for a closet or any space.
Old 1 week ago
  #9
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jhbrandt's Avatar
Sorry, you guys are just plain WRONG. This is PHYSICS.

"The ideal decay for a listening room your size is around .2 sec. .15 sec is acceptable and .1 sec and below sounds like a pair of Headphones. Mind you we are talking across freq from 63hz to around 10khz."
"I think .2-.25 secs is a good balance but right now Im at .14 and its sounds like Im in a box."
"When a room is trapped correctly even at .15 sec, the sound characteristic is more airy and clear sounding i would say and definitely not low mid heavy."
"Exactly.
Considering that the room is relatively small, there can't be too much absorption."

The above quotes are wrong, very wrong.

Here is how you determine the decay characteristics of ANY space;
The average value of reverberation, Tm, measured over the frequency range 200 Hz to 4 kHz should be: Tm = 0,25 (V / V0)1/3 s
There is permissible rise in Tm @ 63Hz of 25%. (from 200Hz to 63Hz).
where:
V: volume of room
V0 : reference volume of 100 m3.

This calculation is metric.

This is subjective. In other words, the recommended Tm is ‘Room Volume-Dependent’. One-size does not fit all.

The value of reverberation of a room (Tm) is an assessment of quality. This is #1 on the list of importance when analyzing a room. FR (frequency response) plots are around #9 on the list due to the capricious nature of these measurements and the procedures followed.

The above calculations are included in my Room Mode Calculators. See my resources page. - The associated industry documents are also available there.

Cheers,
John
Old 1 week ago
  #10
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I think one should make some rough calculations of the "air-occupying" stuff one has within the room too. My empty outer concrete shell has an internal volume of 72,45 m³. I got a bit surprised about the result when I added up the volume of the innerwall materials + "stuff" in the room. The net air volume within the concrete shell came down from 72,45 m³ to about 65,25 m³.

(Solid and airproof stuff like wooden studs, panels and sealed speakers were given an air occupancy factor of 100%, a bookshelf half-filled with books 50%, a leather sofa say 40% air occupancy. 56 "objects in total like internal wall materials, treatment and "stuff", reduced the volume by 7,2 m³ / 254 ft³.)

72,45 m³ gives Tm 225 ms, "allowed" deviations: 200-65 Hz; up to281 ms, 200-8000 Hz tolerance of +/- 0,05 s gives max 275 ms and min 175 ms, measured as adjacent 1/3 octaves.

65,25 m³ gives Tm 217 ms, "allowed" deviations: 200-65 Hz; up to 267 ms, 200-8000 Hz tolerance of +/- 0,05 s gives max 267 ms and min 167 ms measured as adjacent 1/3 octaves. So all in all, those 7,2 m³ didn't make that much of a difference but still, easily measureable with REW. (Measured T60 versus frequencies can vary from one place to another within the room though, -as a normal sized room isn't a diffuse field.)
Old 4 days ago
  #11
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jhbrandt's Avatar
Quote:
Originally Posted by Adhoc View Post
I think one should make some rough calculations of the "air-occupying" stuff one has within the room too. My empty outer concrete shell has an internal volume of 72,45 m³. I got a bit surprised about the result when I added up the volume of the innerwall materials + "stuff" in the room. The net air volume within the concrete shell came down from 72,45 m³ to about 65,25 m³.

(Solid and airproof stuff like wooden studs, panels and sealed speakers were given an air occupancy factor of 100%, a bookshelf half-filled with books 50%, a leather sofa say 40% air occupancy. 56 "objects in total like internal wall materials, treatment and "stuff", reduced the volume by 7,2 m³ / 254 ft³.)

72,45 m³ gives Tm 225 ms, "allowed" deviations: 200-65 Hz; up to281 ms, 200-8000 Hz tolerance of +/- 0,05 s gives max 275 ms and min 175 ms, measured as adjacent 1/3 octaves.

65,25 m³ gives Tm 217 ms, "allowed" deviations: 200-65 Hz; up to 267 ms, 200-8000 Hz tolerance of +/- 0,05 s gives max 267 ms and min 167 ms measured as adjacent 1/3 octaves. So all in all, those 7,2 m³ didn't make that much of a difference but still, easily measureable with REW. (Measured T60 versus frequencies can vary from one place to another within the room though, -as a normal sized room isn't a diffuse field.)
Not really, that's actually wrong. The room volume is calculated EMPTY. The resulting RT60 curve is predicted on THAT. THEN, you treat the room to meet that predicted spec.

It IS pretty simple.

It is correct that a normal-sized room does not have a 'proper' diffuse field. But it DOES have a problematic ambient field. You can test the room Dc. The Dc (critical distance) of any good mix room should be approximately the smallest dimension.

Cheers,
John
Old 4 days ago
  #12
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Thanks John. That acoustics and intuition don’t go hand in hand, I have noticed that several times.

But, do you have an explanation why it would be incorrect to subtract massive objects, ”stealing air volume”, from inside the shell volume? To ”test ideas”, I often mentally change a situation to an extreme. One such exteme would be if a huge pile of drywalls was placed from floor to ceiling in the room. Shouldn’t that have an impact on the calculated T60 versus the empty shell volume, after all quite a bit of air volume have been reduced. And if so, why shouldn’t spread out solid objects of a certain volume have an impact on calculated T60?

(Within the concrete bunker of 72 m³, I get a T60 around 200 ms without subs and around 330 ms with the subs connected. I’m quite happy with that, no boomy bass to speak of.)
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Ideal Vocal Room decay time-200403-361-cm-right-front-subs.jpg   Ideal Vocal Room decay time-200403-361-cm-right-front-without-subs.jpg   Ideal Vocal Room decay time-200403-spectrogram-361-cm-right-front-subs.jpg  
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