EXPERIMENTS! EEEERIIIIK, PLeaz DEESAAAART, pag 7 and 8

[arthur noxon]

EAR PLUGS (What the heck is Caothic?)

RE: Bass heavy mixes, it could be the room or it could be, as they sometimes say “there is no accounting for taste…”

RE: Hearing test curves. This is your hearing threshold test, the quietest sounds you can hear, and you are doing great.

RE: Fletcher Munson Curves. Thanks for posting. What they show is “equal loudness”. This means that each of the lines plot the dB level and frequency for tones that all sounds that all seem to be equally loud.

For loud sound, the dB level for bass has to be only slightly stronger than in the treble range (above middle C) so that all the tones or notes seem equally loud. For quiet sound, the dB level for bass has to be a lot stronger than the treble so that all the tones or notes seem equally loud.

When you take a track and mix it into a quiet passage you would boost the bass so it sounds full in playback. But later, if you take the same track and mix it into a loud passage, you have to cut back or eliminate the bass boost. Otherwise it is overbearing in the bass.

If you mix a quiet passage with the volume turned way up in the studio, you will produce a quiet passage that has way weak bass.

What other Fletcher Munson old wives tails can people think up or already know about from bitter experience?

Arthur Noxon
Acoustic Engineer

[AVare]

What other Fletcher Munson old wives tails can people think up or already know about from bitter experience?

More appropriate to Foley, but still recording. A quiet effect is recorded and monitored at a low level. It sounds fine. In the dubbing stage it is mixed at a high level and all sorts of rumble is heard.

Rumbling, er, rambling,
Andre

[arthur noxon]

RE: Foley work and Fletcher Munson curves

Wow, I like that story. Makes perfect sense. You didn't hear the low frequency rumblings when played pack at low to moderate levels in the Foley control room. But later, in a different mixing environment, it gets pumped up and needs to be EQ'd to dump the deep bass that was captured on the track but passed by was un-noticed during initial monitoring.

So, the Foley studio likes to know at what listening level the track is going to be used in the final mix so the product they deliver is cleaned up, sonically balanced and ready to go at that listening level.

I should know, but nothing comes to mind. Is there a line level / pre amp styled widget out there in audio land that is a Fletcher Munsen curve based volume control? I googled, didn't find anything for sale but a spattering of interest, stories and diy circuits.

See: http://www.extron.nl/company/article.as ... control_ts

http://music-electronics-forum.com/show ... php?t=4117

Thanks,
Arthur Noxon
Acoustic Engineer
www.tubetrap.com

[timogiodeson]

EAR PLUGS (What the heck is Caothic?)

Ops..Sorry , I'm kind of illiterate...

Here how LOUD my drums are inside my room
I have a Radio Shack Digital Sound Level Meter....
Of course I don't play this loud and continuously, but sometimes it happens with drums... also depend on the style of music.
The drum was in one side of the room near a corner and the sound level meter placed 2 inc above drummer head.


A Weighting
Bass Drum, Max 95dB (rock punchy Kick)
Snare Drum , Max 107 dB
Small 8" tom , Max 102 dB
16 inc floor tom , Max 99 dB
Cymbals, Max 109 dB

C Weighting
Bass Drum, Max 107dB
Snare Drum , Max 115 dB
Small 8" tom , Max 112 dB
Floor tom , Max 110 dB
Cymbals, Max 107 dB

Looking to the numbers above let me understand why my desire is to treat 100% of the walls around me... I definitely don't need extra reflections from hard surfaces on top of the direct sound..!

Considering the curve of my hearing audiogram test , doctor suggestions , RT60 curve, Fletcher Munson curves, Drums dB's, 1/2 sec goal and my acoustic tile ceiling....
I guess the first think I should worry about, are the 4K..!
In page 585 of the Master Handbook of Acoustic there are some absorption coefficients...
looks like:
Carpet: indoor/outdoor pick at 4Khz
125 Hz 250 Hz 500 Hz 1Khz 2 KHz 4Khz
0.01, 0.05, 0.10 , 0.20 , 0.45 , 0.65
What about some indoor /outdoor carpet for the walls for the 4K ?

Otherwise.... I will reduce the size of my room with soft 4 inc all around and forget about reflections of any kind, T60s 70s, 80s, and stuff!!

It is too loud here!!

You know what?
What about a very very DEAD room that sound good instead!!!?
A Fletcher Munson 80dB's curves?
basically with a little bass rise, more dead toward the 5K, and a couple mirrors for the 8-20K ? Possible??

[BIG8]

Finally you are getting to the right conclusions

For that small practice room, you've got to forget about RT60, else you'll get the direct sound (which is already loud enough) + the reflections which will sustain the high SPL in time to worsen ear damage potential. You can lively up the room in the upper bands to make it less dead, once sufficiently absorbed> SPLs controlled, and frequency corrected, of course, unless you don't care about that .

You are not suppose to adapt a room's response to your hearing curves, your brains does that for you.

Fletcher munson's curves are for people to know there are different hearing responses at different SPLs, so that we know why something sounds different at different levels.

[Eric_Desart]

1) The doctor said the curve is never flat... that's why everybody like to turn up a little the treble..?
Also my right ear curve look worst than the left ..
but the doctor said the curve it's normal and above hearing loss. Also I went there just after playing...

2) The acoustic inside that little testing room was great ! I was able to see how it's made, 100% coverage 4 inc flat soft and dense black foam with a perforated metal filter in front, very dense almost like metal burlap! , a very small room probably 5x5,

3) ......... Interesting, my audiogram hearing test curve is similar to Fletcher Munson curves look!!...

1) It depends also on age. Normal hearing situates between -10 and 20. Your audiograms shows you have to take care.
http://en.wikipedia.org/wiki/Audiogram

2) Such a small room can sound great since it's absorb higher frequencies and in the very lows the room is small meaning you get a smoother respons on the very low frequencies. Such a room is designed to be relative dead in the measurement range.

3) What you entered here are NOT the H.Fletcher–W.A.Munson curves dating from 1933 (and only executed/tested on 7, or was it 13, 7 I think, people if remembering correct). Can't remember number exactly now, but I was amazed when reading this for the first time.
The picture you showed are the D.W.Robinson and R.S.Dadson curves from "A re-determination of the equal-loudness relations for pure tones" in Br. J. Appl. Phys. 7, 166-181 (1956).
They are/were integrated in the ISO standard ISO 226:1987
In 2003 a revision of the latter standard with new curves was published (based on several years of study and a co-operation of several countries.
That's now ISO 226:2003 and can be seen as the best current available.
Important however is to know that this relates to pure tones (binaural) in free field conditions at frontal incidence.
About loudness in function of frequency lots exist.
http://en.wikipedia.org/wiki/Equal-loudness_contour
http://en.wikipedia.org/wiki/Fletcher%E ... son_curves
http://en.wikipedia.org/wiki/Robinson-Dadson_curves
http://www.nedo.go.jp/itd/grant-e/repor ... is-01e.pdf

Taking the very small test sample of Fletcher Munson into account I think it's more accidental that the name became that known (in the audio world). Lots of in-between curves were published over the years.
On the web you'll see that names of authors and curve pictures often don't match.

It's the typical net behavior: we find a picture with curves and we know a name, let's copy and combine them. Rarely you'll find the boundary conditions in and for which they were measured.
I believe if 5% of the people publishing these pictures on the net ever saw the original papers in their proper context, I think I'm overestimating this.
For the industry a lot of such curves are designed in function of loudness/annoyance versus frequency and level specific dedicated to specific uses.

That your audiogram looks as these equal-loudness curves is that your ears, where they are most sensitive are also easiest subject to impairment.

[timogiodeson]

Finally you are getting to the right conclusions

I hope!

[timogiodeson]

...
1) It depends also on age. Normal hearing situates between -10 and 20. Your audiograms shows you have to take care.
http://en.wikipedia.org/wiki/Audiogram

Yes I will.

...
2) Such a small room can sound great since it's absorb higher frequencies and in the very lows the room is small meaning you get a smoother respons on the very low frequencies. Such a room is designed to be relative dead in the measurement range.

Sound great.. 4 inc black flat soft dense foam and a metal burlap in front!!!

...
3) What you entered here are NOT the H.Fletcher–W.A.Munson curves dating from 1933 (and only executed/tested on 7, or was it 13, 7 I think, people if remembering correct). Can't remember number exactly now, but I was amazed when reading this for the first time..............................................................

You see? How confusing for me? ...
I don't even trust my own EQ Wizard measurements anymore.. ..

...
That your audiogram looks as these equal-loudness curves is that your ears, where they are most sensitive are also easiest subject to impairment

Yes , the 4K... probably cymbals and snare,
First step, musicians earplugs , Second step, tuning the room .

So..as a starting point,
My acoustic tile ceiling that peak at 500hz,
+ indoor/outdoor carpet on the walls for the 4K,
+ 8 pounds floor to ceiling with Lenrds behind in the 4 corners for the low end
+ some mirrors or similar far away from the drums for the 8-20K
will be H.Fletcher and ears safe enough plan?

Otherwise... I'm going to 4inc all over the places and forget about all !!!

Thanks again.

[Eric_Desart]

The drum was in one side of the room near a corner and the sound level meter placed 2 inc above drummer head.

C Weighting
Bass Drum, Max 107dB
Snare Drum , Max 115 dB
Small 8" tom , Max 112 dB
Floor tom , Max 110 dB
Cymbals, Max 107 dB It is too loud here!!

You know what?
What about a very very DEAD room that sound good instead!!!?

Timo

Was that measured in Slow or Fast? (setting in SLM)

What you need is an averaged (all boundaries) flat absorption around 30, max 35%, whatever RT follows from that.
Forget that Fletcher existed.

I don't know what all happens in your room now.
For the very highs you can paint these tiles ones more to neutralize even further. Air absorption and objects will also contribute to the very highs.

I should need to see such a room to get the feel why you need that broad corner absorbers.
Forgive me timo that I can't be of more use to you.

[timogiodeson]

Timo
Was that measured in Slow or Fast? (setting in SLM)

All, slow and fast, average etc... I measured in various ways to make sure, playing with different techniques , continuously etc.. Those numbers can vary of 2 or 3 dB's in the various ways, depends how I play the instrument..
I do trust this measurements with the sound level meter!
and yes cymbals and snare are very loud and damaging here...

(When I said I don't trust my measurement I was talking about the old room EQ wizard measurements...yesterday I started taking new measurements with a different approach, I will post everything in a couples of days)

But I do trust the measurements I did with the sound level meter(dB's of my drums)

Sorry I guess I don't understand the rest of your message...

This can be an idea...?
My painted acoustic tile ceiling absorption should peak at about 500HZ...
corner traps should peak at about 100hz
Indoor outdoor carpet (walls) should peak at about 4K
and mirrors or similar should bring back 8 to 20K ..
No???

Sorry I'm trying to understand your last message...
Do you mean 35 % coverage of flat broadband absorption on the walls without worrying about broad corner traps ?
or
all boundary 100% coverage with a flat material that absorb just about 30-35% of the sound uniformly at all frequencies? (like my initial idea in page 1)?

[claudio_yak]

Dear TIMO,
I have found your research pretty interesting, and appreciated your detailed studies and testes. You pictures and graphics demonstrate professionality and competence.

Let me share with you my experience with polystyrene.
I would be pleased if you will comment on my case:

I decided to set up a small studio in Rome, Italy. It is a square roome of 5 x 5 meters (and 2,5 meters height), in the basament of my building.

Other than the usual targets for a studio (insulation and acoustic) I had to solve the problem of cold, in winter time.

Since my budget was very limited, I started by putting a second-hand carpet on the floor ($20), then I decided to install a layer of polystyrene (1,5 cm thickness) on the four walls and on the top of the studio, to solve the termic problem. The initial idea was to put some super-specific-costly material on top of the polystyrene, as soon as I get the money.

The polystyrene layer costed me $ 100. The result was funcional and good-looking, so I started playing in the studio.
Immediately I noticed that polystyrene had a very good response in terms of acoustic too.

Regarding the drums: you do not feel like "playing inside your head" with all that sound in your ears.

Guitar: clean sound is perfect (I play Jazz mostly). I can put the amp any place, it sounds all right. Everybodu can hear me, I can hear everybody. Distortion can be affected by excess of reflection, but it would anyway, if too loud.

Bass: the carpet plays its role, no problem. Tha walls with polystyrene are not affecting the sound, which remains well separated regardless where you put the amp. Probably the flat surface of the polystyrene helps distributing the bass frequencies in the room, so that the result is homogeneous.

Piano: Same result as for the clean guitar.

Conclusion: I changed my mind and decided not to put anything on top of the polystyrene. I stayed with my $ 120 studio, and all friends like to come and play!

I would like to know audience opinion on this, and particularly ask TIMO if he did try this alternative and, if yes, what was the result.

Thanks

[Eric_Desart]

Sorry I'm trying to understand your last message...
Do you mean 35 % coverage of flat broadband absorption on the walls without worrying about broad corner traps ? [/color][/b]
or
all boundary 100% coverage with a flat material that absorb just about 30-35% of the sound uniformly at all frequencies? (like my initial idea)?

No I meant it in the Sabine like average.
Getting an average of 30% over all boundaries should mean you have to include the floor as well.

What I meant is that, as a relative small practische room, or room to record drums you must control these reflections. 30% average comes close to a control room.
Hence having a reverberant room will cause modes to become too explicit and the drums (meant for much larger room) too loud.
With 30 to 35% I mean an average over the boundaries, not an average of the material itself. 35% is already a rather low reverb.

What I meant is exactly what I told in the beginning: corner absorption and wall/ceiling absorbers.
I rather have less absorbers working linear and reflecting parts on the walls than filling my walls with non-linear absorption taking care of the highs, ignoring lows.

Basically you have to go to the traditional treatment, so many people apply in their small rooms, and with your drums it's even more important to control too much reverb.

You have to treath your room until it sounds right, no matter what the RT will be.
An RT in such a small room is more a result than a target.

Why things are exactly as you desribe I don't know.
Resonancies of these tiles by mounting method?, still too much absorption of these tiles in the very highs, which you could solve by additional painting layers?

Anyhow if you add more treatment (not too much in the highs), automatically this whole treatment will equalize somewhat.

If you add an absorber over absorbing material, you just can't simply add absorption. Hence it's not simply applying Sabine.
Further the more absorption you apply the less effective it will become per unit in function of Sabines (which is why Eyring made his formula as improvement on Sabine's approach, whom had to work with nowadays primitive means to find his relationships. Reverb times were measured by ear with a stopwatch or however these things looked like or called around 1900).

If you don't have enough absorption in the vertical corners you still could use the horizontal corners between walls and ceiling.

If you should have too much high frequent absorption by your absorbers, you easily can solve that by spanning plastic foil over them which will gradually diminish absorption towards the highs.

You can think about a cloud as well over your drum kit.

For me this becomes too extensive (matter of available energy) trying to figure out what happens in your current room and why.
If I should play for couple of hours in your room I should likely feel the what and why, but I'm not there. I should knock on everything, with my fist or vingers (depends), I should look and feel what you have made already.
And if you want to do it yourself just use the described methods you find in this forum.
Physics works the same in your room than in other ones.
The specific factors related to your construction are hard to figure out like this.
But if you use corner absorption (horizontal, possibly vertical and play with absorbers you will get there and this new added treatment will dominate the existing one.
And highs are easy to solve.
With diffusers you can't get to the very lows of your kick drums, and the highs can easily be corrected, even afterwards.

You can play with claudio_yak's suggestion if you like, but then I feel: "There we go again".

[Eric_Desart]

I would like to know audience opinion on this, and particularly ask TIMO if he did try this alternative and, if yes, what was the result.

Claudio,

If you feel good in that room that's the most important thing.
From an acoustical point of view it's hard to judge.
You tell you mounted polystyrene. I diectly wonder how is this mounted? are there membrane effects involved. Which type exactly?

Carpet helps but in the mid and highs.

In how far do modes trouble you or not?

You use unconventional methods, but that doesn't matter if you're pleased with it.

[timogiodeson]

Dear TIMO,
I have found your research pretty interesting,

Let me share with you my experience with polystyrene.
I would be pleased if you will comment on my case:.....

Thanks Claudio,
I grow up In Europe rehearsing in garages made with Eggs cartons and Polystyrene, everybody did that, and I have good memory about it! I never complained about the sound or suffered with my ears...some how for many peoples that was it,
but was long time ago.. and right now to be honest I don't remember exactly the sound of this rooms.... cannot compare

I remember my first practice room, a small room, made with 100% coverage eggs cartons , I was amazed by the sound after I completed my work.. so happy, I still remember !
But there was a big window in that room...

My second and last room had a different shape with non parallel walls and the walls where made with very soft kind of stones, and the ceiling was covered completely with tick mattress kind foam
sounded amazing too!

what can I say...maybe in Europe rooms sound better:)?

Today all this stuff is considered by most of the experts...bad for acoustic and fire hazard
but I grow up playing and rehearsing in places like that and now that instead I have the opportunity to study, and and do it better , I still can't make ... go and figured it out! Will see..
Polystyrene maybe act as a membrane...and for sure it is softer than drywall and reflect less..
No idea!
Enjoy your room the way it is!
thanks

[timogiodeson]

No I meant it in the Sabine like average.
Getting an average of 30% over all boundaries should mean you have to include the floor as well.
What I meant is that, ..........................
...........For me this becomes too extensive (matter of available energy)

Eric, thank you very much for your help, I know must be very difficult and energy consuming for you, every time you answer you write a book!
You are very generous .
Thank you.
From now on , if you feel to replay to my questions please just say YES or NOT or NOT SURE, it will be enough for me.

All I can do in exchange , follow the instructions, and sharing measurements , pictures etc