my studio is about 17'x23'x8' with carpet floor, sheetrock walls and
ceiling. no drapes or other acoustic damping materials. baby grand
piano, chairs, music cabinets, etc. i do a variety of mostly
classical acoustic instrument recording, solos, duos, small ensembles,
like flute and piano, violin and harp, oboes, etc. my gear is pretty
good now, and i can tell that my room holds my sound back more than
anything else at this point. but i dont know if i should make the
room deader, like a big isolation area, or if i should make the room
more live for a more natural ambience. should i add drapes, etc, or
should i replace the carpet with a wood floor? or will this room
alwasy be crappy just because it has an 8' ceiling? thanks for your
comments.

On 25 Aug 2003 09:47:59 -0700, (jnorman) wrote:

my studio is about 17'x23'x8' with carpet floor, sheetrock walls and
ceiling. no drapes or other acoustic damping materials. baby grand
piano, chairs, music cabinets, etc. i do a variety of mostly
classical acoustic instrument recording, solos, duos, small ensembles,
like flute and piano, violin and harp, oboes, etc. my gear is pretty
good now, and i can tell that my room holds my sound back more than
anything else at this point. but i dont know if i should make the
room deader, like a big isolation area, or if i should make the room
more live for a more natural ambience. should i add drapes, etc, or
should i replace the carpet with a wood floor? or will this room
alwasy be crappy just because it has an 8' ceiling? thanks for your
comments.


With a ceiling that low, I think you will need less reflection rather
than more. I'd suggest dampening some sections of the room to break
up some of the early reflections. With luck you might be able to rid
yourself of enough to make the room more pleasant sounding. You might
also find it necessary to kill all ambience and create it
electronically. You never know untill you try a few things. If you
can determine which wall(s) cause the most sonic grief, work on the
creases where walls and ceiling meet. This probably won't cure
everything but it usually goes a long way. I used R-19 encased in
cut-to- fit canvas for my room. It made a big difference. (Make sure
to do all fiberglass work outside so that you don't contaminate your
gear or room. Good idea to where a particle mask, too.)




Rick Ruskin
Lion Dog Music - Seattle WA
http://liondogmusic.com

On 25 Aug 2003 09:47:59 -0700, (jnorman) wrote:

my studio is about 17'x23'x8' with carpet floor, sheetrock walls and
ceiling. no drapes or other acoustic damping materials. baby grand
piano, chairs, music cabinets, etc. i do a variety of mostly
classical acoustic instrument recording, solos, duos, small ensembles,
like flute and piano, violin and harp, oboes, etc. my gear is pretty
good now, and i can tell that my room holds my sound back more than
anything else at this point. but i dont know if i should make the
room deader, like a big isolation area, or if i should make the room
more live for a more natural ambience. should i add drapes, etc, or
should i replace the carpet with a wood floor? or will this room
alwasy be crappy just because it has an 8' ceiling? thanks for your
comments.

Try using a good spectrum analyzer and a good (flat) mic and throwing some
sweep tones and also some pink noise into your room. The flatter the better (in
most cases) but on the other hand, a good live room is cool for acoustic stuff.

(jnorman) wrote in message . com...
my studio is about 17'x23'x8' with carpet floor, sheetrock walls and
ceiling. no drapes or other acoustic damping materials. baby grand
piano, chairs, music cabinets, etc. i do a variety of mostly
classical acoustic instrument recording, solos, duos, small ensembles,
like flute and piano, violin and harp, oboes, etc. my gear is pretty
good now, and i can tell that my room holds my sound back more than
anything else at this point. but i dont know if i should make the
room deader, like a big isolation area, or if i should make the room
more live for a more natural ambience. should i add drapes, etc, or
should i replace the carpet with a wood floor? or will this room
alwasy be crappy just because it has an 8' ceiling? thanks for your
comments.


Add *diffusors* instead of damping material... check out RPG and
Auralex' stuff. Your risk is that if you damp with curtains you won't
really take care of lo-freq resonance, which should be dealt with by
means of Helmholtz resonators and bass traps, such as TubeTraps. Check
out ethanwiner.com for examples of home made bass traps; Ethan also
records / playas classical music (cello, I believe).
Oh yeah.... Check out F. Alton Everest's "Handbook of Acoustics" for
more info.
Acoustics are a very complex argument and should be dealt with care.
G'luck!

Paul Weber

JN,

my studio is about 17'x23'x8'

That's not a great ratio, but it's large enough to get good results by
adding proper acoustic treatment.

with carpet floor, sheetrock walls and ceiling. no drapes or other
acoustic damping materials.

For the type of acoustic music you're recording you should reverse the floor
and ceiling. Remove the carpet to have a reflective floor, then make the
ceiling partly or fully absorbent with rigid fiberglass. A hard floor
doesn't have to be expensive wood. Lineloum or even bare painted cement
sound equally good.

i dont know if i should make the room deader ... or if i should make the
room more live for a more natural ambience.

Your room is large enough to take advantage of ambience. Ideally you want
some ambience, but controlled by selective placement of absorbing materials.
That is, you don't want all the surfaces bare OR all covered with drapes or
other absorbers. Applying absorption in a vertical striped pattern is good,
as is a 2x2 or 2x4 foot checkerboard pattern. For a room that size you want
somewhere between 20 and 40 percent of the surfaces covered with absorbing
material - maybe a little more if you include the ceiling in that figure.
Note that all rooms need absorption at low frequencies as well as at mid and
high frequencies. This requires material much more substantial than just
drapes or thin foam.

or will this room always be crappy just because it has an 8' ceiling?

Not at all, and that's the main reason to deaden the ceiling. A ceiling that
is 100 percent absorptive is identical acoustically to a ceiling that's
infinitely high. That is, it doesn't matter if sound is not reflected down
from the ceiling because it absorbs or because it's very far away.

I suggest you see my Acoustics FAQ which explains room treatment in great
detail. It's 10th in the list on my Articles page:

www.ethanwiner.com/articles.html

--Ethan

Scott wrote
More live doesn't mean it has to be less flat.

I'm not for sure but would more live = less dead? And does alot of damping not
make things live?

Raymond,

would more live = less dead? And does alot of damping not make things
live?

Live and dead are opposite. An empty bedroom in a new house is very live. A
closet filled with clothes - damping material - is very dead. Good recording
and control room are somewhere between those extremes. See my Acoustics FAQ
referenced above for much more detail.

--Ethan

Raymond wrote:
Scott wrote
More live doesn't mean it has to be less flat.

I'm not for sure but would more live = less dead? And does alot of damping not
make things live?

More live means a longer reverb time. More dead means a shorter reverb
time. (Given the same room volume, of course.)

You can have a room without severe frequency response aberrations that is
live, or one that is dead.

You can have a room with bigtime standing waves in the low end, and you
can have one with bigtime peaks and dips in the top end, that is live.
Or one that is dead.

A lot of damping will make things dead, but most damping is frequency
selective. You throw a lot of thin foam into a room and now your high
frequencies are damped, but the low end is unchanged. You put a bass trap
in, and your low frequencies are damped, but the high end is unchanged.

You can also use diffusion to change the frequency response of the room
without changing the overall reverb time much. Bookcases can be a very
handy tool for this.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

scott wrote
More live means a longer reverb time. More dead means a shorter reverb time.
(Given the same room volume, of course.)

Larger room + longer Reverb time?

I'm not for sure but would more live = less dead?

Yes, more live means more reflective, more reverberant, less absorptive.

And does alot of damping not
make things live?


A lot of damping does not make things live. Damping is absorption.



Scott Fraser

be careful with diffusors. They seem to make a dead room more life but
that is mostly a high frequency issue. and with those vertical
diffurors you get some nasty high frequency tones/hiss in the
reflection back in the direction of the source, especially at shallow
angles of incidence.

in my humble opinion we should not be running to the RPG's of this
world and spend hundreds of dollars in... adding nasty sound. yes, if
you ahve a back-slap echo a schroeder diffusor may help, but if the
area that has a shallow angle of incidence to these surfaces is
important (because audience, mics or musicians sit there) try other
solutions.

in this small room, I'd start with base absorber of the panel type.
see ethan's site for great links and examples. The surface of these do
not necessarily have to be absorbtive, they could be simply 1/4"
plywood. if that is too much, glue a small layer of felt on them
(1/16" construction felt can don wonders). If you'd panel one of the
walls (preferably the heaviest one), size them so that wall is no
longer in parallel with the opposite wall, that way you can also
'trap' some flutter conditions that might exist. then dampen (read:
felt/fiberglass) the wall towards which the reflections are directed.

just a few thoughts...

rt60


On 26 Aug 2003 03:38:51 -0700, (Paul C. Weber) wrote:

(jnorman) wrote in message . com...
my studio is about 17'x23'x8' with carpet floor, sheetrock walls and
ceiling. no drapes or other acoustic damping materials. baby grand
piano, chairs, music cabinets, etc. i do a variety of mostly
classical acoustic instrument recording, solos, duos, small ensembles,
like flute and piano, violin and harp, oboes, etc. my gear is pretty
good now, and i can tell that my room holds my sound back more than
anything else at this point. but i dont know if i should make the
room deader, like a big isolation area, or if i should make the room
more live for a more natural ambience. should i add drapes, etc, or
should i replace the carpet with a wood floor? or will this room
alwasy be crappy just because it has an 8' ceiling? thanks for your
comments.


Add *diffusors* instead of damping material... check out RPG and
Auralex' stuff. Your risk is that if you damp with curtains you won't
really take care of lo-freq resonance, which should be dealt with by
means of Helmholtz resonators and bass traps, such as TubeTraps. Check
out ethanwiner.com for examples of home made bass traps; Ethan also
records / playas classical music (cello, I believe).
Oh yeah.... Check out F. Alton Everest's "Handbook of Acoustics" for
more info.
Acoustics are a very complex argument and should be dealt with care.
G'luck!

Paul Weber

Raymond wrote
Larger room + longer Reverb time?

Opps that should have been = not +

Scott wrote
That's also true. In a small room, most of the reflections you get are
going to be short reflections from nearby surfaces. If it's a very live
room, the reverb time can still be fairly long.

Being a small room = many bouncing reflections? (depending on room
construction) If its a small room the reflections (some frequencies) can be
sharp or hard to control no matter what you do to the walls?

In a large room, the reverb time will be longer, because most of the
reflections are coming from distant surfaces.

Yes, frequency is time/distance or size right?

Whether high or low frequency reflections predominate is a seperate issue.

So if your planning on using the room for a live guitar (small set range of
frequencies) will be different than if you want to use it for a full set of
drums (larger set of frequencies) etc.?


In general, short reflections from nearby objects dominate so much in a
small room that reverb time becomes a useless measurement. But we can still
talk about "perceived liveness."

Your talking about pre/early-decay (I think) right? So a room (hopefully a
large one) with no points of obstruction will give a larger revearb time yes?

Forgive my ?'s but It maybe worth discussing.

Raymond wrote:
Raymond wrote
Larger room + longer Reverb time?

Opps that should have been = not +

Scott wrote
That's also true. In a small room, most of the reflections you get are
going to be short reflections from nearby surfaces. If it's a very live
room, the reverb time can still be fairly long.

Being a small room = many bouncing reflections? (depending on room
construction) If its a small room the reflections (some frequencies) can be
sharp or hard to control no matter what you do to the walls?

If it's a live small room, there will be many bouncing reflections. If
it is a dead small room, there won't be. In all cases, the reflections
that predominate will be ones that come a short time after the original
peak, rather than longer term ones. This is why small rooms can sound boxy
if they are very live.

In a large room, the reverb time will be longer, because most of the
reflections are coming from distant surfaces.

Yes, frequency is time/distance or size right?

The only time you want to think about frequency in terms of distance is
when you're worrying about standing waves. In this case, the reflections
that come back can be any frequency at all... the reflectivity of the
surfaces in the room can have high end or low end dominating, it doesn't
matter to the fact that it's a live room.

Whether high or low frequency reflections predominate is a seperate issue.

So if your planning on using the room for a live guitar (small set range of
frequencies) will be different than if you want to use it for a full set of
drums (larger set of frequencies) etc.?

Not really, you still want a room with a generally flat frequency response
and a fairly long and even reverb. The length of the reverb decay that
you want for a drum kit will probably be longer than you want for guitar,
but it's easy to shorten it or deaden it with gobos.

In general, short reflections from nearby objects dominate so much in a
small room that reverb time becomes a useless measurement. But we can still
talk about "perceived liveness."

Your talking about pre/early-decay (I think) right? So a room (hopefully a
large one) with no points of obstruction will give a larger revearb time yes?

Not necessarily. But if there are no points of obstruction, there will be
more of a chance that you'll get discrete echoes from the surfaces rather
than a nice even decay. And that's bad too.

Forgive my ?'s but It maybe worth discussing.

The F. Alton Everest introduction to small studio acoustics is well worth
checking out.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

RT,

with those vertical diffusors

One thing many people don't realize is diffusion is not useful in small
rooms. According to Dr. Antonio's FAQ at the RPG site, the distance between
your ears and a diffuser should be at least ten feet. Less distance than
that and adding diffusion actually harms the sound. This also holds for
diffusion on the ceiling. Unless your ceiling is 15 or more feet high,
putting a diffuser there is a mistake.

--Ethan

scott wrote
The F. Alton Everest introduction to small studio acoustics is well worth
checking out.

This what you where talking about?
http://www.amazon.com/exec/obidos/tg...-2824837-98536
31?v=glance

Or this?
http://www.amazon.com/exec/obidos/tg...=pd_sim_books_
5/002-2824837-9853631?v=glance&s=books

Both look good with mixed reviews.

Hello Ethan,

devils advocate: sure doesn't work in a very small room to have flat
surfaces all around. most diffusion is of course in practice cause by
furniture and the different materials used for floors, walls and
ceilings.

with regard to RPG's science, I tend to take their interpretation of
their own research with a grain of salt. I have seen and heard spaces
with their material and applied with their endorsement that makes me
doubt their science. gives me the same feeling sometimes as when I
read about dr. bose. their attitude is to design a room and then buy
the acoustics via mail-order, next-day delivery; it just doesn't work
that way.

when I mention diffusion I do not necessarily refer to expensive
panels from a factory. I refer to a means to diffract some of the
sound. the diffusion should be scaled to the need (1/4 wavelength
idea, plus the broadening of the bandwidth by use of varying
materials).

skylines are possbily one of the better panels for smaller rooms as
far as the factory panels is concerned, because it is a combination of
mid frequency absorption and some decent high frequency diffusion. can
take care of some harshness that is just short of identified flutter.

with the vertical diffusors (schroeder type) angle of incidence is the
most important issue. if that is close to straight-on for source and
destination, the side effects can be acceptable... just don't use too
much of it, it hurts when you play flageolets on the A string ;-)

rt60


On Thu, 28 Aug 2003 10:34:30 -0400, "Ethan Winer" ethan at ethanwiner
dot com wrote:

RT,

with those vertical diffusors

One thing many people don't realize is diffusion is not useful in small
rooms. According to Dr. Antonio's FAQ at the RPG site, the distance between
your ears and a diffuser should be at least ten feet. Less distance than
that and adding diffusion actually harms the sound. This also holds for
diffusion on the ceiling. Unless your ceiling is 15 or more feet high,
putting a diffuser there is a mistake.

--Ethan

Being a small room = many bouncing reflections? (depending on room
construction)

Not necessarily. You can have a very dead small room, as well as a large room
with a lot of direct reflections. Large rooms tend to diffuse into reverb,
though.

If its a small room the reflections (some frequencies) can be
sharp or hard to control no matter what you do to the walls?

Not necessarily. You can make an anechoic small room. What you can't do is fool
the ear into believing the room is larger, because the early reflections are
easily discernible as coming from a short distance away.

So a room (hopefully a
large one) with no points of obstruction will give a larger revearb time yes?

Reverb decay time is often longer is larger rooms, but it's very easy to make
rooms where the opposite is true. It's all in the ratio of absorption to
reflection of the surfaces. All things being equal (which they never are, but
let's say they are for example) a large room that is an identical version of a
small room, just multiplied in every dimension, will be more reverberant than
the identical small room, & will be easily perceivable as larger due to the
longer path for first reflections, greater degree of diffusion & greater
absorption of highs in the contained air.

Scott Fraser

Ethan,

Au contrare, I absolutely agree that it is good to reduce the level of
the first reflections. But now we're talking about a control room, and
not a recording space, I suppose.

Diffusion at that the point of the primary reflection will widen the
image quite a bit. I would be inclined to put diffusion on the side
walls behind the listening position for stereo listening, and scatter
the back wall in bigger blocks. The complication is that this is the
area where the first wall-reflection for the surround loudspeaker is
traced. When we start to get into that, there are multiple paths and
ideas to follow, and we'd have to get to real-life situations before
determining what would be the better approach, as part of this is the
location and angle of the surround loudspeaker and its radiation
pattern. Then add-in the issues involving the HRTF (see latest JAES
for some new research on that) and the use of 'side-panned' source
locations, and you'll find that interpreting acoustics is a journey
similar to playing BWV 1007 thru 1012 ;-)

rt60



On Fri, 29 Aug 2003 11:28:49 -0400, "Ethan Winer" ethan at ethanwiner
dot com wrote:

RT,

most diffusion is of course in practice cause by furniture

Good point.

when I read about dr. bose

Nuff said. :-)

Dr. Bose may well be a genius - I have no idea - but all the products of his
I've heard are pretty awful.

Anyway, thanks for the clarification. I'm still getting up to speed on
diffusion. As I understand it, the main problem with installing diffusers on
nearby surfaces is you still have "early reflections," and broadly diffusing
them just confuses the imaging even more. The studio designers I've
discussed this with all told me they recommend broadband absorption on any
nearby surface that could yield a primary reflection, which makes sense to
me. But conflicting opinions are always welcome!

--Ethan

Scott,

Those are all good points, and I'll add just two relevant bits about reverb
Amount versus reverb Time in large versus small rooms:

The primary cause of absorption in a room is the walls, floor, and ceiling.
Even with relatively hard surfaces like painted sheetrock, the walls still
absorb much more than the air. Since it takes longer for, say, five bounces
to travel around a large room, that is the primary reason a large room seems
more reverberant. Not so much that there's more reverb expressed as dB below
the original, but mainly that it lingers longer.

Also, in small rooms those bounces happen so quickly that much of the
reflected sound combines in the ear with the original direct sound. Anything
that happens within 20 milliseconds or so is not heard as separate echoes or
ambience. So the first few bounces, which are the most audible, blend with
the original source.

--Ethan

Scott,

the ear can easily determine the size of the room by the time displacement
of the early reflections from the direct sound.

Yes, exactly.

--Ethan

Ethan,

Undesirable indeed. Hence the absorption at the point of the first
reflection. Not perse problematic for determining ambiance, depending
on the definition of that word (JAES is tackling the definition
envelopment in the latest issue, another one of those abused words; I
do seem plug that fab mag here, maybe I should quote Asterix and
Obelix sometime). Worse is that basic aspects like the AB gap and
unstable image will be harder to verify. Ambiance ma be fuzzier in
balance, but does not need to be problematic.

The amount of action you can take to reduce the level of that first
lateral refection in the control room does beg the question if 10 dB
down (which is sort-a the goal here) is enough to fall within the
definition of natural, herin referring to your 'artificial and
unnatural' ;-) Defining that may become a tricky adventure.

Anyway, just developing into splitting hairs here, and trying to find
out what your lingo is. So far seems to go well, but then again,
you're a cellist, or so I deduct ;-)

rt60



On Sat, 30 Aug 2003 09:28:35 -0400, "Ethan Winer" ethan at ethanwiner
dot com wrote:

RT,

Diffusion at that the point of the primary reflection will widen the image
quite a bit.

Okay, but anything that artificially and unnaturally widens the image when
making mix decisions seems like a bad idea, no? Sort of like mixing in a
room with too much ambience, so you apply too little to the mix.

you'll find that interpreting acoustics is a journey similar to playing
BWV 1007 thru 1012 ;-)

Does this mean there's another cellist in the group?

--Ethan

RT,

Undesirable indeed. Hence the absorption at the point of the first
reflection.

Perhaps I misunderstood because originally you said, "Diffusion at the point
of the primary reflection will widen the image quite a bit." So I thought
you were proposing that.

does beg the question if 10 dB down (which is sort-a the goal here) is
enough

How much an absorbing panel attenuates is less relevant than how low in
frequency it works to. Even half an inch of 703 rigid fiberglass absorbs
100% at the upper mids and above. As the material is made thicker and denser
it's absorption extends lower. I recently added absorption on the side walls
and ceiling of my control room to make an RFZ, and I used 2-inch thick
705-FRK to make the zone effective down to low frequencies.

trying to find out what your lingo is. So far seems to go well, but then
again, you're a cellist, or so I deduct ;-)

Ha, my "lingo" is all over the map as I have MANY interests - music theory,
skepticism, acoustics, electronic circuits, consumerism, guitar and cello
playing, audio and recording, computer programming. It's all on my web site
www.ethanwiner.com.

--Ethan

Ethan,

I had seen your website, in fact, referred some-one to in in this
thread. I was kidding around a bit. Anyway, we seem to be running in
parallels... I like the skepticism part quite a bit.

The 2" will get you to about -10dB btw; that is about what we do. I'll
look up some measurements for that, if you like.

RU attending the AES convention by any chance?


rt60

off to the etude nicknamed humbadada...



On Tue, 2 Sep 2003 08:53:49 -0400, "Ethan Winer" ethan at ethanwiner
dot com wrote:

RT,

Undesirable indeed. Hence the absorption at the point of the first
reflection.

Perhaps I misunderstood because originally you said, "Diffusion at the point
of the primary reflection will widen the image quite a bit." So I thought
you were proposing that.

does beg the question if 10 dB down (which is sort-a the goal here) is
enough

How much an absorbing panel attenuates is less relevant than how low in
frequency it works to. Even half an inch of 703 rigid fiberglass absorbs
100% at the upper mids and above. As the material is made thicker and denser
it's absorption extends lower. I recently added absorption on the side walls
and ceiling of my control room to make an RFZ, and I used 2-inch thick
705-FRK to make the zone effective down to low frequencies.

trying to find out what your lingo is. So far seems to go well, but then
again, you're a cellist, or so I deduct ;-)

Ha, my "lingo" is all over the map as I have MANY interests - music theory,
skepticism, acoustics, electronic circuits, consumerism, guitar and cello
playing, audio and recording, computer programming. It's all on my web site
www.ethanwiner.com.

--Ethan

RT,

RU attending the AES convention by any chance?

Not only attending, but also exhibiting! I've gone to most of the NYC shows
for the past 30+ years, but this is the first time I have a company with
audio products to sell. Please stop by the RealTraps display at Booth #1045
and say Hi.

off to the etude nicknamed humbadada...

I don't know that one. What instrument do you play?

--Ethan

If I am allowed to go I will certainly visit.

rt60

Try Duport...


On Wed, 3 Sep 2003 10:23:23 -0400, "Ethan Winer" ethan at ethanwiner
dot com wrote:

RT,

RU attending the AES convention by any chance?

Not only attending, but also exhibiting! I've gone to most of the NYC shows
for the past 30+ years, but this is the first time I have a company with
audio products to sell. Please stop by the RealTraps display at Booth #1045
and say Hi.

off to the etude nicknamed humbadada...

I don't know that one. What instrument do you play?

--Ethan