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Author Topic: Does Wood Really Sound Warm?  (Read 7467 times)

Ethan Winer

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Does Wood Really Sound Warm?
« on: February 01, 2009, 12:59:57 pm »

The conventional wisdom is that wood surfaces impart a "warm" sound to a room, compared to cement, linoleum, or drywall. But is this really true? I'd appreciate the opinions of resident experts here about this article:

Surface Reflectivity

Note I'm addressing surface reflectivity only, not potential resonances from wood structures etc.

Thanks guys!

--Ethan

rankus

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Re: Does Wood Really Sound Warm?
« Reply #1 on: February 01, 2009, 02:07:08 pm »



I've always thought of wood as more midsy/punchy ...

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compasspnt

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Re: Does Wood Really Sound Warm?
« Reply #2 on: February 01, 2009, 03:50:20 pm »

My rooms have almost all wood surfaces.

I find that, whilst they are not necessarily "warm," they do seem to reflect a certain sweetness back on the high end that is somehow more pleasing than what (I recall from other, different rooms) comes back from cement or drywall.

Not scientific though, and not direct comparison...just empirical observation...

And it is probably the design of the rooms more than the surfaces which dictate the sound.

Looks nice though...

Imparts an image of warmth...
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Re: Does Wood Really Sound Warm?
« Reply #3 on: February 01, 2009, 07:42:12 pm »

Wood normally couples with sound waves so they will amplify the sound coincident with it's modes, augmenting the reverberation time at that frequencies, reflecting others, transmitting others, and absorbing others depending on the damping of the wood / system.

There can be the case where a lower frequency excites upper modes, gaining the sound some kind of harmonics that we enjoy. It's not by accident that musical instruments are empirically made of wood, because in many cases the way it vibrates pleases the ear a lot.  

But the bottom line is that what happens with sound in wood is really complicated because it depends a lot of variables so is hard to predict, but not impossible with the help of appropriate software, study, prototypes and testing.

Thomas Jouanjean

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Re: Does Wood Really Sound Warm?
« Reply #4 on: February 02, 2009, 08:26:06 am »

Ethan Winer wrote on Sun, 01 February 2009 11:59


Note I'm addressing surface reflectivity only, not potential resonances from wood structures etc.



In this case, it's not the reflectivity that matters, it's the resonances and therefore the various possible re-emissions.

In the table, it says "wood parquet on concrete" which can obviously not show those phenomenons as it implies the wood is structurally stiffened by its coupling to the concrete.

So this info cannot be used to support one or the other answer.

You'd need measurements of a non-dampened or stiffened wood surface... and you'd probably need to test various woods of various densities as well, as they behave differently.

Hope this helped.

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Thomas Jouanjean
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #5 on: February 02, 2009, 05:13:03 pm »

Thomas Jouanjean wrote on Mon, 02 February 2009 08:26

You'd need measurements of a non-dampened or stiffened wood surface.


I found more complete data and updated my article this morning to include both parquet floor bonded to cement, plus a wood floor on joists. I also replaced the data for glass, changing from a large surface that can absorb bass to a smaller piece that has less self-resonance. Here's the link again if anyone cares and would like to comment further:

Surface Reflectivity

Thank guys!

--Ethan

PookyNMR

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Re: Does Wood Really Sound Warm?
« Reply #6 on: February 03, 2009, 07:00:59 pm »

Ethan Winer wrote on Sun, 01 February 2009 10:59

Note I'm addressing surface reflectivity only, not potential resonances from wood structures etc.


Question:  Wouldn't the different resonance properties of the wood and it's attachment be a factor in the overall sound?  

I'm just wondering how useful it is to separate the reflectivity and resonance issues of different materials.  Is there a reason why a more holistic approach is not useful?

Thanks.
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #7 on: February 04, 2009, 03:18:00 pm »

PookyNMR wrote on Tue, 03 February 2009 19:00

Wouldn't the different resonance properties of the wood and it's attachment be a factor in the overall sound?


It depends what the wood is attached to. Wood flooring on top of a cement foundation changes the surface only because there's nothing to resonate. Thin paneling over drywall probably won't change the resonance of the drywall too much, especially if it's several layers thick.

Quote:

Is there a reason why a more holistic approach is not useful?


The more data we have, the better. Always. In this case, it was easy to derive reflectivity from available data. To do a more comprehensive test would cost a lot of money! So I didn't even try to compare a wall made of wood only versus other materials. As explained in the article, it's common for people to ask if adding wood on top of their basement or garage cement floor is useful, so that's all I tried to address.

--Ethan

andrebrito

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Re: Does Wood Really Sound Warm?
« Reply #8 on: February 05, 2009, 05:54:13 am »

I will say the same thing I told on GS

Using just Surface Ref. for this matter is a very simplistic approach

and

Sound absorption increases a lot in wood when sound is at higher angles of incidence
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #9 on: February 05, 2009, 01:58:44 pm »

andrebrito wrote on Thu, 05 February 2009 05:54

Using just Surface Ref. for this matter is a very simplistic approach


It's the best I could do for no cash outlay. Laughing

Quote:

Sound absorption increases a lot in wood when sound is at higher angles of incidence


Can you post those numbers here? I'd love to learn how that varies with angle.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #10 on: February 05, 2009, 07:07:49 pm »

Am I allowed to attach a picture on this forum from a book from a public library ? About copyright issues...
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garret

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Re: Does Wood Really Sound Warm?
« Reply #11 on: February 05, 2009, 10:25:42 pm »

andrebrito wrote on Thu, 05 February 2009 18:07

Am I allowed to attach a picture on this forum from a book from a public library ? About copyright issues...


Yes.  First off, whether you own the book or borrowed it from a library is beside the point.   Buying the book doesn't give you any more rights to reproduce material than borrowing it from a friend or a library.

If it's your scan, and if you credit the source, it is "fair use" under US copyright law.  I don't know if the copyright laws are different in Portugal, but most countries are less strict than the US.

This is an educational forum, and you are not posting to make a direct commercial gain.  You are allowed to post small portions of copyrighted works, for scholarly purposes, if you properly cite the source.  

The "small portion" criteria (also called "substantiality") is key.   If you were to post a scan of a chart that is available as an individual product... then no, it's not allowed.   But if you are just posting a scan that is one chart from a long book, sure that's fine.

That's why you'll often see people recommend you not repost entire articles you find on another website.   You can post a portion, or some excerpts, then link to the full article.

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andrebrito

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Re: Does Wood Really Sound Warm?
« Reply #12 on: February 06, 2009, 06:54:49 am »

http://i39.tinypic.com/2n66o85.jpg

From Acoustics of Wood book - pg. 22 - Voichita Bucur - Springer Editions

Thanks for the explanation !
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Thomas Jouanjean

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Re: Does Wood Really Sound Warm?
« Reply #13 on: February 06, 2009, 10:40:10 am »

andrebrito wrote on Fri, 06 February 2009 05:54

http://i39.tinypic.com/2n66o85.jpg

From Acoustics of Wood book - pg. 22 - Voichita Bucur - Springer Editions

Thanks for the explanation !


This is great, I love those...

I shows so very well the subrmerged part of the "acoustics" iceberg...  Thanks for posting!
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Thomas Jouanjean
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franman

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Re: Does Wood Really Sound Warm?
« Reply #14 on: February 06, 2009, 12:41:25 pm »

I knew that wood sounded warmer!!!   Cool
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Fig

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Re: Does Wood Really Sound Warm?
« Reply #15 on: February 06, 2009, 05:57:44 pm »

franman wrote on Fri, 06 February 2009 11:41

I knew that wood sounded warmer!!!   Cool


It certianly burns warmer than say, concrete logs.  Sorry.

Regarding wood in general - most musical instruments are made of the stuff.  Must be a reason, right?

The best to use on CR construction comes from trees that have fallen in the forest but nobody heard them.   Cool

Have nice weekends, folks!

Fig


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andrebrito

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Re: Does Wood Really Sound Warm?
« Reply #16 on: February 06, 2009, 08:18:31 pm »

Can you imagine a guitar made of concrete !?! hahaha
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Bill_Urick

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Re: Does Wood Really Sound Warm?
« Reply #17 on: February 06, 2009, 08:27:15 pm »

andrebrito wrote on Fri, 06 February 2009 20:18

Can you imagine a guitar made of concrete !?! hahaha


It would be way too heavy.
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Re: Does Wood Really Sound Warm?
« Reply #18 on: February 06, 2009, 08:40:48 pm »

Exactly, no more crazy rock 80's solo guitar and headbangers with guitars made of concrete... the world would really be a sad place lol
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Re: Does Wood Really Sound Warm?
« Reply #19 on: February 07, 2009, 08:23:14 am »

Everything mentioned in this thread is "correct" and it's a good discussion---but wood LOOKS "warm", and utilizing wood carefully in a studio adds a psycho-acoustic effect into a design. We add nice wood elements, carefully placed to avoid reflections, or used diffusively, to "warm up" the look of a room, and it presents a total picture in the users mind of a cozy environment--if a room sounds great and looks great and then it all feels great to be in there. Of course, exposed wood will be mostly a reflective material, and where and how you install it should be considered carefully.  Used as flooring---well ANY floor except 6" shag carpet will be predominantly reflective, and considered in the acoustic calcs...but wood flooring can look marvelous, wood trim and features adds visual warmth and interest. Just consider the reflections.
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #20 on: February 07, 2009, 12:02:14 pm »

andrebrito wrote on Fri, 06 February 2009 06:54

From Acoustics of Wood book - pg. 22 - Voichita Bucur - Springer Editions


That's great Andre! But what thickness is the wood, and how was it mounted? It seems unintuitive to me that wood mounted on a solid substrate could absorb near 100 percent at midrange frequencies.

--Ethan

Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #21 on: February 07, 2009, 12:07:01 pm »

Fig wrote on Fri, 06 February 2009 17:57

most musical instruments are made of the stuff.  Must be a reason, right?


Yes, but this is not a good analogy. Wood used in violins and cellos is very thin, and is shaped to intentionally vibrate. String instruments need strong resonances to create the desired timbre, and emphasize harmonics from the strings. But studios are never designed with intentional resonance! The purpose of resonating wood in studios is to absorb bass, not add high-Q resonances into the room. This is a common misconception, and I made that point in my article:

Quote:

I've seen people argue that wood adds a pleasing quality to a room in the same way wood affects the tone of a fine violin. But that's a false analogy because the thin, resonant wood in a violin is meant to vibrate and add pleasing overtones. Versus wood on a floor or wall that is much thicker, and is anchored solidly to the wall or floor backing. Indeed, resonances in a musical instrument are desirable and necessary, but good listening rooms must aim to avoid all resonances as much as possible.


--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #22 on: February 07, 2009, 01:51:37 pm »

I think this was tested in an impedance tube, would need to check the book again on the library
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Thomas Jouanjean

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Re: Does Wood Really Sound Warm?
« Reply #23 on: February 17, 2009, 01:41:12 pm »

Ethan Winer wrote on Sat, 07 February 2009 11:02

It seems unintuitive


Everything about acoustics is...
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Re: Does Wood Really Sound Warm?
« Reply #24 on: February 17, 2009, 05:28:45 pm »

Thomas Jouanjean wrote on Tue, 17 February 2009 13:41

Everything about acoustics is [unintuitive]


It makes no sense that wood on a slab could absorb 80 to 90 percent around 1 KHz. The data I've seen is more like 6 percent. So this tells me the wood in that test was thin and suspended in the air. Or at least not mounted flat and bonded to cement as is done for floors, which is the intent of my article.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #25 on: February 17, 2009, 09:30:27 pm »

test done in a impedance tube I think
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Re: Does Wood Really Sound Warm?
« Reply #26 on: February 18, 2009, 03:57:49 am »

Ethan Winer wrote on Tue, 17 February 2009 16:28

Thomas Jouanjean wrote on Tue, 17 February 2009 13:41

Everything about acoustics is [unintuitive]


It makes no sense that wood on a slab could absorb 80 to 90 percent around 1 KHz. The data I've seen is more like 6 percent. So this tells me the wood in that test was thin and suspended in the air. Or at least not mounted flat and bonded to cement as is done for floors, which is the intent of my article.

--Ethan

Ethan, the test was done in an impedance tube, like Andre said. So it can't be suspended in the air. But it's placed against something real hard and heavy (bottom of the tube) which implies high density, denser than cement. Don't confuse impedance tube test with reverb chamber tests.

The graph shows little absorption with perpendicular incidence. About what you mention, between 5 and 10%.

If the piece of wood were to resonate (and surely it does on it's own) it would be best excited  by a perpendicular incidence. The graph tends to rule out that phenomenon to explain the absorptive behaviour with incidence as the piece is placed against something hard. It's therefore dampened.

It could be a measurement problem, I just had a chat about it with a colleague from Leuven University which does those tests now and then, and while unlikely, he said it could be the result of a leak in the tube seal around the sample. But don't you jump to conclusions too fast because this measurement was likely performed by the book or it would not have been published and I would not question it so far.

Although the test results show important coefficients when an incidence other than 0
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Thomas Jouanjean
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #27 on: February 18, 2009, 11:17:37 am »

Thomas Jouanjean wrote on Wed, 18 February 2009 03:57

Ethan, the test was done in an impedance tube, like Andre said. So it can't be suspended in the air. But it's placed against something real hard and heavy (bottom of the tube) which implies high density, denser than cement. Don't confuse impedance tube test with reverb chamber tests.


I know about impedance tubes and I know how they're different from reverb rooms. If the wood sample were placed against a solid backing, then how could they have measured at different angles? My guess is it was a thin piece of unattached wood, rotated in free air at the far end of the tube. So the wood panel itself was likely resonating and thus absorbing. You say "We need more data" and I agree. In this case we need to know more details about the test! Very Happy

Quote:

The graph shows little absorption with perpendicular incidence. About what you mention, between 5 and 10%. If the piece of wood were to resonate (and surely it does on it's own) it would be best excited by a perpendicular incidence.


Perpendicular is 90 degrees, yes?

Quote:

For your article to be worth any definitive conclusion, you'd have to measure in a reverb room with a parquet installed and without.


The data I used to calculate reflectivity was presumably measured in a lab. So I don't know why it shouldn't be considered valid.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #28 on: February 18, 2009, 11:29:10 am »

IIRC, 0
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Thomas Jouanjean
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Ethan Winer

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Re: Does Wood Really Sound Warm?
« Reply #29 on: February 18, 2009, 12:22:06 pm »

I don't know for sure either, but it seems that absorption would be maximum on axis and minimum when "grazing" edgewise.

The bottom line for me is that it makes no sense that a slab of wood bonded to solid cement can absorb 1 KHz by 80 to 90 percent at any angle!

The huge drop in absorption around 3 KHz is also very telling, no?

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #30 on: February 20, 2009, 03:13:44 am »

Ethan Winer wrote on Wed, 18 February 2009 11:22

I don't know for sure either, but it seems that absorption would be maximum on axis and minimum when "grazing" edgewise.


In many cases, absorption is better with an incidence other than perpendicular.

Ethan Winer wrote on Wed, 18 February 2009 11:22

The bottom line for me is that it makes no sense that a slab of wood bonded to solid cement can absorb 1 KHz by 80 to 90 percent at any angle!

The huge drop in absorption around 3 KHz is also very telling, no?

--Ethan


Sure, you can believe what you want. I understand you can be puzzled by this - but please listen to what 3 professional acousticians told you here. This is a complex issue, and likely no one can give you a definitive answer. What I'm telling you is: don't draw fast conclusions based on partial data. You are way too definitive in your approach of things. Be cautious. I would take that article off-line.

Again, I agree it's healthy to question things - and it's okay to wonder about the absorption of wood as measured in the graph. I would not rule it out though because it is likely a serious measurement. If we take the example of your bass traps, how much sense does it makes that such a thin "limp" membrane makes them according to your data so much better in the LF range? When there is considerably more energy involved at 100Hz than 1kHz?

I think it's about time this discussion ends, understanding that the partial data we have is not enough to rest anybody's case. We have various opinions stated, and some hints at what may be happening - let's leave it at that Smile
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Re: Does Wood Really Sound Warm?
« Reply #31 on: February 20, 2009, 02:20:25 pm »

Thomas Jouanjean wrote on Fri, 20 February 2009 03:13

 don't draw fast conclusions based on partial data.

As far as I can tell, the data I based my reflectivity amounts on is not partial. And assuming the data was measured in a lab, the test conditions are well known - measured flat on a floor - and so correspond directly with the premise of how different floor materials sound. If I'm missing something important I'd love to hear it! Or if you think the way I converted absorption to reflectivity is flawed, I'd like to hear that too. I'm not trying to be combative, but so far I'm not convinced there's anything wrong with my approach.

This has nothing to do with who is or is not a professional acoustician. I don't understand way so many people, not just here but at Gearslutz too, want to cease the discussion of something that is so critically important to studio design. Confused

Quote:

I would not rule it out though because it is likely a serious measurement.

I'm sure it's a serious measurement. But without knowing the thickness of the material being tested, or whether it was against a solid backing or in free air, or even knowing for sure how 0 and 90 degrees are intended, that to me falls under what you call "partial data," no?

BTW, I just found that book on Google Books and here's what little it says about the wood specimens:

"Measurements were performed on disks of 31 - 101 mm in diameter [1.2 - 4 inches] and 2 - 11 mm thickness [0.08 - 0.43 inches]."

So this implies to me that they were investigating properties of wood as used in musical instrument construction, with the wood free to vibrate. Versus bonded to a rigid backing like a floor.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #32 on: February 20, 2009, 02:24:50 pm »

I don't see how you can imply that... what I imply is that the samples are circular because of the Kundt tube geometry maybe ?

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Re: Does Wood Really Sound Warm?
« Reply #33 on: February 20, 2009, 03:06:49 pm »

andrebrito wrote on Fri, 20 February 2009 14:24

I don't see how you can imply that.

Imply what? I made a number of statements. Very Happy

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #34 on: February 20, 2009, 03:15:52 pm »

Ethan Winer wrote on Fri, 20 February 2009 13:20


but so far I'm not convinced there's anything wrong with my approach.


Your approach is that you seem to take a very particular case, from which you generalize and draw conclusions, which are IMO sloppy at best. You also fail to digest or really consider information that goes against your conclusions. This is not the way to do it.

Ethan Winer wrote on Fri, 20 February 2009 13:20

I don't understand way so many people, not just here but at Gearslutz too, want to cease the discussion of something that is so critically important to studio design. Confused


I agree it is important to studio design, this is why so many of us here are very cautious with the issue. Designing is about finesse of judgement and balance. Acoustics is as much a science as it is an art.

We all see what your position is, and see where this is going.

What I would like to see to take this discussion further and keep it interesting is data about how various implementations of wood in a room affects the overall response. Then we can see where (and if) it makes a difference.

If anybody has more hard data or interesting, precise information to share with us about this subject, please PM me. It will be very welcomed!

Until then, I'm locking this thread.


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Thomas Jouanjean
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Re: Does Wood Really Sound Warm?
« Reply #35 on: February 20, 2009, 06:27:14 pm »

Okay - more extracts from the book out of which Andre took the Graph, and to which Ethan provided a link in Google Books.

It indicates that:

1- behaviour is very dependent on conditions of installation and species of wood.

2- It also indicates that wood has a real absorptive capacity, and that although the impedance tube measurement can be influenced by external factors, it is pretty reliable and the behaviour of the wood as shown in the graph can be explained by the "motion of the air contained in the cavities of wood cells".

3- It also states that in some other and particular set of conditions, wood can also present a lower and more even absorptive behaviour:

"Watanabe et at (1967) noted that for all species analyzed, when thin specimens (10 mm maximum thickness) are exposed to the incident sonic energy in the anisotropic planes of wood LR or longitudinal tangential (LT), the absorption coefficient is small and quite constant for all frequencies."

IMHO, what this shows in fine is that wood has indeed a tendency towards audible "coloring", but the complexity of it's behaviour and multiple ways of implementing it prohibits any precise pronostic as to the extent of the "coloration".

So, all in all, it likely has a sound, and how much you get of it will vary quite a bit from case to case. It is also likely to behave differently from say, Linoleum or Concrete, the authors mentioning the effect of air in the wood cell structure as a reason for it's absorptive behavior, properties (air) that cannot be found in similar fashion in both linoleum and concrete.

This part of the article does not assess the re-emission factors in wood, which could possibly lead to more coloring.

Of course, YMMV.

Thread unlocked Smile

I hope other contributors can come up with more infos!
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Re: Does Wood Really Sound Warm?
« Reply #36 on: February 20, 2009, 06:44:51 pm »

Ethan Winer wrote on Wed, 18 February 2009 11:22


The bottom line for me is that it makes no sense that a slab of wood bonded to solid cement can absorb 1 KHz by 80 to 90 percent at any angle!
--Ethan


Well, sounds like it does make sense! The authors state that only wood of less than 10mm thickness in a very particular set of conditions shows low and even absorption like showed in your article.

Otherwise, wood seems pretty absorptive around 1kHz. The data you used in your article was for a very specific case, as a parquet of "over 10mm thickness" would be, according to the authors, expected to show more than enough absorptive behaviour to effectively have an impact on perceived sound.
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Re: Does Wood Really Sound Warm?
« Reply #37 on: February 21, 2009, 01:42:54 pm »

Thomas Jouanjean wrote on Fri, 20 February 2009 18:27

Thread unlocked Smile


Great, thanks. I didn't understand locking a thread where acousticians are discussing such an important acoustics issue.

Quote:

The data you used in your article was for a very specific case, as a parquet of "over 10mm thickness"


All I did was find "Internet" data Very Happy for various materials. I'm not so sure that > 10 mm is a standard thickness for parquet wood flooring. 10 mm is 0.4 inches, and the first link Google came up with is for tiles 0.31 inches thick (7 mm):

http://www.fastfloors.com/catalog/productline.asp?productlin eid=19247&productid=134727&REF=CZT1334564

Quote:

I hope other contributors can come up with more infos!


I too would love to see more data for different types of standard wood-over-concrete floors. We may settle this yet. Laughing

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #38 on: February 21, 2009, 02:31:03 pm »

Ethan Winer wrote on Sat, 21 February 2009 12:42


Great, thanks. I didn't understand locking a thread where acousticians are discussing such an important acoustics issue.


I had a feeling this would go the GS way (running in circles leading to bickering etc).
I will never allow this on this forum.

Ethan Winer wrote on Sat, 21 February 2009 12:42

All I did was find "Internet" data Very Happy for various materials. I'm not so sure that > 10 mm is a standard thickness for parquet wood flooring. 10 mm is 0.4 inches, and the first link Google came up with is for tiles 0.31 inches thick (7 mm):


We just installed a 1.8cm thick beautiful oiled parquet in a studio, CR & LR. Darius @ Amsterdam Mastering did just the same too.

Your original question: "The conventional wisdom is that wood surfaces impart a "warm" sound to a room, compared to cement, linoleum, or drywall. But is this really true?"

With the information we have, the answer leans toward a "Yes, but...", not the opposite. Especially since you are talking about "surfaces" in your question which is indefinite (so it could be just any surface, not just the floor!).

It has a sound of it's own, which by looking at the graph can explain the adjective "warm" that is used in describing it.

Your article's conclusion: "Although some people believe that wood and cement and linoleum all sound different, any difference they heard is most likely due to other factors such as the size and shape of the rooms, and other surfaces present."

Can you agree that this is not the right conclusion to give? It's rather misleading.

IMHO, I think you should rework it all and show at least that thickness matters a lot in how much of the "sound" you get. You should as well at least mention and talk a bit about the re-emission factors, which are IMHO pbly the most important ones. Adressing only reflectivity, and furthermore only partially feels to me like looking at the whole subject through a peephole at night.

What do you think?
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Re: Does Wood Really Sound Warm?
« Reply #39 on: February 21, 2009, 04:09:21 pm »

Thomas Jouanjean wrote on Sat, 21 February 2009 14:31

I had a feeling this would go the GS way (running in circles leading to bickering etc). I will never allow this on this forum.

Excellent. It's a shame the GS moderators don't have the same attitude. Sensible people are perfectly capable of discussing things without getting angry or tossing insults. Only a few get frustrated and become nasty.

Quote:

We just installed a 1.8cm thick beautiful oiled parquet in a studio, CR & LR. Darius @ Amsterdam Mastering did just the same too.

I would have loved to see some room measurements before and after putting in the floor! Was the wood on top of solid concrete?

Quote:

With the information we have, the answer leans toward a "Yes, but...", not the opposite.


"The information we have" is the crux of it. I give much more credibility to the data shown in my report than to the data in the book Andre posted. First, the data I used to calculate reflectivity agrees with most other data I've seen. It also agrees with what I consider common sense. I know what material sounds like when it absorbs 70 percent or more at mid and high frequencies, and wood does not sound like that at all. Below are a few online AbsCo charts, with the one I used first. In all cases, the values for wood on cement are well below 0.10. However, it's entirely possible some or all of these online resources are derived from the same source!

http://www.saecollege.de/reference_material/pages/Coefficien t%20Chart.htm
http://www.acousticalsurfaces.com/acoustic_IOI/101_13.htm
http://online.physics.uiuc.edu/courses/phys199pom/Student_Re ports/Fall02/Alan_Truesdale/Alan_Truesdale_Absorbtion_Coeffi cients.pdf
http://www.sengpielaudio.com/calculator-RT60Coeff.htm
http://www.wsdg.com/dynamic.asp?id=resources/technology/abso rbtion

The reason I discount the data in the book Andre linked is because we have no clue about the specific samples or how they were measured. All we know is a broad range of sizes and thicknesses, but no idea what type of sample is shown in that particular graph. Indeed, what we do know is the samples were most likely not attached firmly to a backing since they were measured at various angles in an impedance tube. I suppose it's possible the wood samples were glued to a thick rigid backing, but I doubt it because doing that makes no sense if the goal is to measure the wood. We also know the samples were thin and small, and the data in that graph disagrees with all the other data I can find.

Quote:

Your article's conclusion: "Although some people believe that wood and cement and linoleum all sound different, any difference they heard is most likely due to other factors such as the size and shape of the rooms, and other surfaces present."

Can you agree that this is not the right conclusion to give? It's rather misleading.

I cannot agree yet. Sorry!

Quote:

show at least that thickness matters a lot in how much of the "sound" you get.

That's a great idea. Do we have data for wood on cement at various thicknesses?

Quote:

You should as well at least mention and talk a bit about the re-emission factors

Does re-emission happen with wood on cement, or only with wood on joists? Do we have any re-emission data? I agree that the more data we can see, the more complete the conclusion will be.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #40 on: February 21, 2009, 05:48:47 pm »

Ethan Winer wrote on Sat, 21 February 2009 15:09


Was the wood on top of solid concrete?


Yes.

Ethan Winer wrote on Sat, 21 February 2009 15:09


"The information we have" is the crux of it. I give much more credibility to the data shown in my report than to the data in the book Andre posted. First, the data I used to calculate reflectivity agrees with most other data I've seen. It also agrees with what I consider common sense.


You do realise that there is considerably more info on the subject in the article submitted by andre than in any of your supplied data? It's also not a question of common sense but a question of understanding the data. What your data shows is what is also shown and explained as an exception in the Watanabe & Hayashi study: that, all other things being equal, under a certain thickness absorption becomes uniform and lowers.  You can't derive a conclusion like yours, that "wood is no different than linoleum", based on the exception.

That would be common sense.


Ethan Winer wrote on Sat, 21 February 2009 15:09

the data in that graph disagrees with all the other data I can find.



Because it's not the same data at all! Only parts of it bears similarities. Your data only shows (probable) reverb chamber measurements with thin layers - and again it was shown how that affects the results. The book shows much more in-depth measurements, with various samples in various conditions. Therefore it is normal it bears different results with "all the other data you can find".

Ethan Winer wrote on Sat, 21 February 2009 15:09

I cannot agree yet. Sorry!


You don't have to.

But I can't help thinking you fail to see the forest for the tree here. What I expect from this discussion are not final, undeniable facts but to determine the most plausible explanation and to show that this is a complex issue that in itself prevents any straight definitive answer.

We can outline certain behaviours. Concluding like you do in your article is not okay by any remotely scientific standards.

Ethan Winer wrote on Sat, 21 February 2009 15:09

That's a great idea. Do we have data for wood on cement at various thicknesses


I'll check in my database, but we do know now about the 10mm benchmark. That is a lot already! And this phenomenon is not linked to whether or not the wood is on cement or joists. Just thickness.

Ethan Winer wrote on Sat, 21 February 2009 15:09

Does re-emission happen with wood on cement, or only with wood on joists? Do we have any re-emission data? I agree that the more data we can see, the more complete the conclusion will be.


Re-emission is a very, very tricky subject. Way more complex than the one at hand. What you need to know is that it's everywhere in any solidian that vibrates.





Ethan, your question has been answered I believe, by others and myself. We'll have to agree to disagree. My personal view is that your approach is lacking in many ways.

I am going to close that thread now. I don't think we can really go any further and I believe there is enough information for each and everyone interested to make up his own mind about it all - which is what matters.

To everyone, feel free to PM me if you have something relevant to add to the thread. I will then re-open it.
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Re: Does Wood Really Sound Warm?
« Reply #41 on: February 22, 2009, 12:04:51 pm »

Ladies... let's all play nice here please?? I've been on the road all last week and missed this really fun exchange. Let's all agree to 'disagree' and let's ALL act professional and we ALL are professionals.

PS: Glenn, you got any spare popcorn??? Cool
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Re: Does Wood Really Sound Warm?
« Reply #42 on: February 22, 2009, 01:53:55 pm »

Hey Francis,

There is no problem... I just want to avoid endless discussions on the subject when I think we have covered it all and the rest would've been just beating a dead horse and re-debating points on and on with a risk of seeing this thread turn like the similar GS thread.

There is no room for that here.

Some users have asked me to reopen, so I will do so. But I would really like something constructive.

If a user has had a problem with the fact that I have closed the thread (seeing me heavy handed when it's not how it should be seen), feel free to PM me about it.  Smile

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Re: Does Wood Really Sound Warm?
« Reply #43 on: February 22, 2009, 02:11:40 pm »

franman wrote on Sun, 22 February 2009 12:04

Glenn, you got any spare popcorn??? Cool

Here ya go:

http://www.freesmileys.org/smileys/smiley-fc/popcorn.gif



Laughing

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Re: Does Wood Really Sound Warm?
« Reply #44 on: February 22, 2009, 02:23:13 pm »

Again, I'm trying very hard not to appear combative, but I feel the important points are being overlooked.

Thomas Jouanjean wrote on Sat, 21 February 2009 17:48

You do realise that there is considerably more info on the subject in the article submitted by andre than in any of your supplied data?

But how does that book address the core question of my article, which is the sound of wood floors over concrete? And how is the data in that book useful if we don't even know the size or thickness of the material sample used for the graph? Why should that incomplete data take precedence over the well-known properties of floor material as shown in every one of the absorption links I posted?

Whatever, we've all made our points. I still feel the burden of proof that a wood floor on cement sounds substantially different than a floor of plain cement has not been met. Thomas, it would be great if you're able to measure this the next time you're about to install a wood floor over a concrete slab.

BTW, this morning I added a second paragraph to the Conclusion part of my article to explain that the data is somewhat limited because it doesn't go higher than 4 KHz. To me this is a minor issue, but I want to be accurate and fair.

--Ethan

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Re: Does Wood Really Sound Warm?
« Reply #45 on: February 22, 2009, 04:40:18 pm »

Volume 13, Number 5 (1967)

Original Articles
Haruto WATANABE, Tsutomu MATSUMOTO, Nobuyuki KINOSHITA, Hiroya HAYASHI
Acoustical Study of Wood Products. I. On the Normal Absorption Coefficient of Wood    

Japan Wood Research Society

This is the published article
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Re: Does Wood Really Sound Warm?
« Reply #46 on: February 22, 2009, 04:48:54 pm »

Ethan Winer wrote on Sun, 22 February 2009 13:23


Thomas, it would be great if you're able to measure this the next time you're about to install a wood floor over a concrete slab.


Ok, I will!

I usually measure at 80% of completion, and then 100%, so what I have now in stock is irrelevant as much more than just the floor is added in the last 20% phase of building.

We will be finishing 2 projects in late March/April, both with wood floors (one is real thick floor, the other cheaper 'Quick-Step' like). I'll try and make a measurement in each of the rooms just before flooring and right after to try and get something usable.

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Re: Does Wood Really Sound Warm?
« Reply #47 on: February 23, 2009, 12:40:13 pm »

I could be totally crazy but installing parquet over concrete in my new room last week changed the sound slightly.  Its a new constructed room with zero absorption (only drywall and a hard floor) so the room is super live and intense.  Installing the wood floor seems to have made it a slightly less crazy sounding.  

I'm by no means an expert but feel pretty confident that the difference I hear isn't in my head.  

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Re: Does Wood Really Sound Warm?
« Reply #48 on: February 23, 2009, 02:45:45 pm »

Oh man, it would have been great if you could have measured the room before and after. This is what's really needed - hard data.

--Ethan
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