EXPERIMENTS! EEEERIIIIK, PLeaz DEESAAAART, pag 7 and 8

Timo, Could you have the above frequency responses rescaled in the vertical (dB) and horizontal axis (zoom in (+) ) to show a range of 30-100dB and 20-500Hz, and show the 1/3 octave plot (hit Ctrl+shift+3) and repost it? Cheers, Jean

Eric_Desart wrote:

Please don't do that. ...

just a quote mistake Eric...

BIG8 wrote:

Timo, Could you have the above frequency responses rescaled in the vertical (dB) and horizontal axis (zoom in (+) ) to show a range of 30-100dB and 20-500Hz, and show the 1/3 octave plot (hit Ctrl+shift+3) and repost it? Cheers, Jean

thank you Jean, yes I will, I need to find the original files probably still in the garage computer I will post later thank you

here...

Eric_Desart wrote:

With corner absorption you can go below 120 Hz without needing 4' width (your 4' x 8' description). See absorption curves on the commercial sites I mentioned and at Studiotips in the FAQ for DIY solutions. Physics doesn't adjust to budgets or space. You could try membrane like absorbers in the corners, but that's testing and tuning. Glenn told me once about his corner solution, but back then Glenn told it was a succes but had no measurements if remembering correct. If I'm wrong Glenn will correct me. I'm always interested in learning.

OK but Nooo..., In my room the size of the porous corner absorber need to be at list 4x8 to be effective in the very low end of the bass drum etc.....(too much space ) !! Also none of the rooms with the corner absorbers has the 1/2 sec RT60 I'm looking 4... the rt60 drop down too much which doesn't sound good at all, plus all kind of unpredictable things in the lows end :roll: basically I prefer the room without treatment...look

Timo, nice emoticon of you beating a dead horse :lol: I don't know why you make the RT60 your reason for treatment choice. Once you get the sound you want, you could always adjust the reflections in the mid/high frequencies. first get the frequencies right, then worry about the rest, after all this is meanly a rehearsal/practice room, right? :D Since you have the RT60s for the room with Lendr, corner traps, polys, 8 pounds etc... could you also post their corresponding frequency response curves, 1/3 oct smoothed + same dB /Hz range as above responses? Cheers, Jean

BIG8 wrote:

...... Since you have the RT60s for the room with Lendr, corner traps, polys, 8 pounds etc... could you also post their corresponding frequency response curves, 1/3 oct smoothed + same dB /Hz range as above responses? Cheers, Jean

Here the measurements. thank you P.S. I made a mistake in the description of of the last RT60 measurement above , (ligt green line) there was only two large 4x8 corner panels in the room, one corner was untreated , and in the last corner just 2 regular lenrds in the floor.

some of my experiments ... I measured various kind of floor to ceiling absorbers in the corner behind the drums, based on what I feel playing the bass drum and also the measurements I believe the large 4x8 panel is much better for the deep low end of a drum set..compared to the others ... sub/mic/drums

untreated corner 4 Auralex Lenrds bass traps 4 Auralex megalenrds super large mega in the floor plus 3 lenrds on top 8 pounds 4" floor to ceiling 8 pounds 8" floor to ceiling 8 punds 4" 4x8 floor to ceiling 2.5 pounds 4" 4x6 Cabinets :-) poly diffusers, without insulation, unsealed 1 layer 5/8 ceiling tiles 3 layers of ceiling tiles 4x8 5/8" ceiling tiles various more 8 pounds fsk 2" 8 pouns fsk 4" 8 pounds 4" fsk toward the walls 8 pounds 4" fsk in both sides 8 pounds 4", with lenrds behind 8 pounds 8" with lenrds behind

Why did you always have the measurement mic pointed at the floor? just curious As long as you are trying things, id suggest installing a drop acoustical ceiling at 16" below hard ceiling, then do some regular r19 on top of that.Its a technique thats been done everywhere for a long time for 'general' commercial sound dampening. Then go from there. That should give absorption of about .40 through the octave bands depending on the tiles used. Thats what they do in office buildings anyway. Polys .. http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1637 id put them across the corners and use the dimensions shown. some spot broadband absorption on the walls adjacent to the instruments (4" of fiber or lenrds etc.) .

mike0370 wrote:

Why did you always have the measurement mic pointed at the floor? just curious

It is omni ...and pointing to the drums, similar to a drum overhead mic. Why? Not good? :? P.S. about the drop ceiling... I have allergies..., I'm worry about all the insulation on top of my head. I glued up/ painted and caulked all my tiles because of that. Thanks.

As you can see, in your last pic, more absorbing-volume is better response. :)

Ro wrote:

As you can see, in your last pic, more absorbing-volume is better response. :)

I'm not sure .....Considering the price and everythings, I like the 4'x8'x 5/8" panel made with cheap ACOSUTIC :lol: ceiling tiles... $8.00 per corner!!! I can still fill up the cavity with R insulation if I want .. What happens to the very low end if I add a $9.00 perforated 4x8 pegboard in front of the ceiling tiles? P.S. My cabinets do better than Lenrds bass traps! ($140 per corners :x ) If anybody here need my used Lenrds, please let me know, half price!!!! I will include the 8 pounds ! 4x8 5/8" cheap ceiling tiles without back filling. only in one corner of the room

Also, the instruments (drums) are probably resonating while the test tone is playing possibly doing weird things. Consider muffling them when you measure, putting a big heavy blanket over them or something. P.s. on a side note, id personally like to see some measurements if you did some bass hangers in that corner , for experimentations sake :wink:, maybe attatch your mineral panels to the ceiling panels temporarily and hang them freely in the corner ----------------------------- . 1 1 1 1 1 . 1 1 1 1 1 . 1 1 1 1 . 1 1 1 . 1 1 . 1 . . . .

mike0370 wrote:

Also, the instruments (drums) are probably resonating while the.......... P.s. on a side note, id personally like to see some measurements if you did some bass hangers in that corner , for experimentations ..... ---------------------------- . 1 1 1 1 1 . 1 1 1 1 1 etc

Yes I did muflled a little the bass drum head etc trying to avoid resonances... was not perfect but Ok ... the rest of the room also with piano instruments etc is not perfect for testing... but I guess I got the idea because in addition to the measurements I did played the drums and I can tell, expecially the 40hz stuff... No I didn't experimented with hangers, what are those numbers?

BIG8 wrote:

Timo, I don't know why you make the RT60 your reason for treatment choice.

I like 1/2 sec ...

BIG8 wrote:

Once you get the sound you want, you could always adjust the reflections in the mid/high frequencies.

It's tricky... absorption effect everything below 1K too, I like 1/2 sec.

BIG8 wrote:

first get the frequencies right, then worry about the rest,

It's tricky :)

BIG8 wrote:

Since you have the RT60s for the room with Lendr, corner traps, polys, 8 pounds etc... could you also post their corresponding frequency response curves, 1/3 oct smoothed + same dB /Hz range as above responses?

It's all in page 4 now, thank you for asking.

Timo, You have pre-conceived ideas which makes it almost impossible for anyone in the 'know' (I'm not one of them) to help you: 1) you want 100% coverage of wall/ceiling >>that will make your room too 'dead' unless you chose weird materials which are not meant for acoustic treatment, like polystyrene, which will screw-up your room in the most ungodly way. 2) you believe corner traps will lower your RT60 too much (not true) and will take up too much space in order to have a noticeable effect in the bass (not true) >>>which you don't seem to care about. 3) you make RT60 value of 1/2 sec a magic criteria which your room must meet, yet I believe you don't really understand what RT60 is (sorry if wrong) and whether it 'really is what you are after, as an acoustic outcome. Your room is too small to make RT60 a valid treatment objective, and, as a practice room, why do you need to have 1/2 seconds across the whole frequency range?? Are you certain that you are not mis-using RT60 to describe your needing a live room, not a dead one, as in a room having a lively upper end?? You are cutting short everyone's attempt at helping you with this RT60 fixture. You are a cheating RT60 obsessed person :twisted: :lol: :asth: 4) you prefer the sound of your untreated room. :roll: What can one say here? "please, don't like it, treat it!!" I suggest you concentrate your best at describing the room and your intended use, leaving the acoustic definitions and terms to the experts...(if they still have the enthusiasm to help you). Cheers, Jean

Yes corner traps lower the RT60 , I'm sure about this! Please believe me! I'm an honest person , , I'm not a cheater, trust me please. it's not a joke, is very true, why nobody want to believe me? watch this video :D http://www.youtube.com/watch?v=XHUvIXtnB7g and this too.. http://www.youtube.com/watch?v=_LHoyB81LnE

Timo, I believe you, and I believe you are an honest person (who is obsessed and cheats :twisted: (((joke)))) Yes, corner traps will lower your RT60 but not "that much". My main message to you is that you are over-focussed on something which you believe is the solution to all your problems <and> a criteria any proposed treatment must meet>>>that is the stumbling block in your reasoning. :( Cheers, Jean

Eric_Desart wrote:

Glenn told me once about his corner solution, but back then Glenn told it was a succes but had no measurements if remembering correct. If I'm wrong Glenn will correct me. I'm always interested in learning.

sorry for being so late... Eric - i had built some large corner staddling polys which did a nice job of absorption and diffusion - we had them lined with 4" mineral wool and the (covered) corner stacked like a superchunk. i cannot attribute the entire effect to this single construct since there were a number of other treatments but overall the effect is lively and even. Terry or Scott @ ST probably have significant data on polys :-) in the case of these threads, i'm seeing a systemic problem of half-complete treatments being tried in one corner or another without regard for commonly used techniques as well as less common ones, and enough coverage to make an assessment on the approach.

OK too All, I admit it, I'm .... continue below

xSpace wrote:

Personally I feel a little cheated. I thought you were just some scatter-brain that could not focus and accept the limitations that existed. While persistence is admirable, this behavior borders on obsession, which is never good.

>I< feel a little cheated is the wording. I worked under the impression this was your first time out...not the second. I was thinking "damn, these folks have already dealt with this, and here I am trying to get them to have another look because this tim guy needs help, seemingly before his head explodes." There was never and is not now anything but the desire that you could correct this acoustical concern. When its all said and done, you've had the best that can be on it...on it!

It's OK X, thanks. ------------------------------------------------------ OK too All, I admit it, I'm depressed and obsessed, I'm chaotic and illiterate, and on top of all I'm a :shot: ...no hopes !! :horse: But please, look to the measurements below and let me know if what I'm trying to explain is literate enough... 1) The first measurement shows the RT60 of the room with acoustic tile on the ceiling only (glue up mount) various measurements in different areas of the room... As you see the absorption of the acoustic tiles with glue up mount pick at about 500hz in my room. (without tiles a room like this drywall/concrete floor will have a much longer RT60 at 1K about 2 sec...) Considering my goal 1/2 sec ( please don't :cen: me), I guess the tiles did a good job until now, probably too good at 500hz, in fact the rt60 it's just below 0.5...there. Then you see from 1K to about 6.00K the rt60 going slight up.. and I'm not worry to much about that... And then from 400hz and below the situation become unpredictable...Lot's of stuff going on... 2) the second measurement shows: * room with ceiling tile only. (green) * room with ceiling tile + additional 12 Lenrds bass traps in 3 of the corners (yellow) * room with ceiling tile + additional 12 lenrds in 3 of the corners + Six 2x4x4" 8 pounds panels across available corners + 4 small ploys on the walls. ( Pink) As you see (yellow line), with just 12 Lenrds in 3 of the corners the RT60 1K to 10K..drop down a lot..too much, ( Lenrds are good High Freq absorbers I can say :D ) Then with additional 2x4x4" 8 pounds absorbers in available corners (pink line) everything drop down between 0.2 sec and 0.3 sec... and everything looks more flat but still with unpredictable things in the low end. Note: The very low end, sounds still the same to me as a player, instead 300hz and up sounds already dead, and below 100hz very booming which make things sound worst to my ear. Note: There is not walls absorption or cloud jet....!!! So, I assume the RT60 from 200hz and up will drop down to 0.1 sec ! :shock: That sound good to you? I want about 1/2 sec evenly across all F....( as a starting point) please don't :cen: me... Questions: 1) How to bring down 3.00K to about 0.5 sec? 2) How to bring down 300hz-90hz to about 0.5 sec ? 3) how to adjust the very low end modes from about 40hz to 125hz ? 4) Look good already.. but how to bring up a little 500hz? 5) How to bring up 10k to about 0.5 sec? How ? Why nobody like me? :)

EAR PLUGS The drum kit has a bandwidth of probably 30 to 16k Hz, but I haven’t measured one. However, the goal is to not damage our ears. What we want is to protect is our hearing. Google and read much good information: “Drummer Hearing Loss” One drummer measured 125 dB,A exposure level with snare, rim shots and cymbal. We want to figure out what part of the frequency range produced by the drum kit is damaging our ears. Then we want to turn the volume down in that frequency range. Use a mic and some spectrum analyzer to figure out what the loudest frequency range is for the instrument you play. At loud sound levels, the ear is equally sensitive at all frequencies. Probably anything over 100 dB needs to be cut down. Look at the dB attenuation response of the ear plugs you use. And remember, just because you have ear pugs, doesn’t mean you have them installed right. Good and simple plugs are the EAR expandable memory foam material. Use once and throw away. You compress roll the foam cylinder into a pencil lead thin roll, slide the compressed cylinder into your ear quickly before it expands, let it slowly expand to fit snugly into your ear. It protects the top end, the most vulnerable range of your ear. The ear is generally gets wacked in the 2 to 6k region. That’s the typical hearing loss “notch”. Ear plugs that protect that region are all that is necessary to provide general protection. Nothing is gained by over damping noise in a lower frequency range, provided that the low frequency energy is not too strong. If you fire cannons for a living, then you probably have to worry about low frequency damage. Drums, probably not. I always wondered about using one of those dog shades to help keep the upper treble sound of the drum kit from getting up around the ears. Didn’t try it yet, though… Possibly I’ll coat both sides of the cone with some good sound absorbing foam, not the kind commonly available, but the stuff noise engineers use for machine noise. The problem with EQing the sound you are making is that you tend to want to correct for the deficiencies in what you are hearing. So if you use foam to EQ sound above 1k, then your drum kit will feel too heavy in the mids and bass and you will lighten up on the power you are delivering to the bass and toms. It’s just like recording engineers. If they work in a room that is bass light (as in acoustic tile ceiling) then they will bring more bass into the mix and end up with a bass heavy record. The musician style ear plugs promote full range damping, all frequencies equally. That sounds nice at first but when the volume goes down, we lose sensitivity to the bass more than we loose sensitivity to the treble. That’s why we have to use bass boost when we turn the volume down. So we don’t want to turn the volume down a flat 20 dB. It has to slope some, 20 dB in the treble is OK but maybe only about 15 dB in the midrange and only 10 dB in the bass. See “Fletcher Munson curves”. Arthur Noxon Acoustical Engineer

arthur noxon wrote:

EAR PLUGS [size=7]The drum kit has a bandwidth of probably 30 to 16k Hz, but I haven’t measured one. However, the goal is to not damage our ears. What we want is to protect is our hearing. Google and read much good information: “Drummer Hearing Loss” One drummer measured 125 dB,A exposure level with snare, rim shots and cymbal. We want to figure out what part of the frequency range produced by the drum kit is damaging our ears. Then we want to turn the volume down in that frequency range. Use a mic and some spectrum analyzer to figure out what the loudest frequency range is for the instrument you play. At loud sound levels, the ear is equally sensitive at all frequencies. Probably anything over 100 dB needs to be cut down. Look at the dB attenuation response of the ear plugs you use. And remember, just because you have ear pugs, doesn’t mean you have them installed right. Good and simple plugs are the EAR expandable memory foam material. Use once and throw away. You compress roll the foam cylinder into a pencil lead thin roll, slide the compressed cylinder into your ear quickly before it expands, let it slowly expand to fit snugly into your ear. It protects the top end, the most vulnerable range of your ear. The ear is generally gets wacked in the 2 to 6k region. That’s the typical hearing loss “notch”. Ear plugs that protect that region are all that is necessary to provide general protection. Nothing is gained by over damping noise in a lower frequency range, provided that the low frequency energy is not too strong. If you fire cannons for a living, then you probably have to worry about low frequency damage. Drums, probably not. I always wondered about using one of those dog shades to help keep the upper treble sound of the drum kit from getting up around the ears. Didn’t try it yet, though… Possibly I’ll coat both sides of the cone with some good sound absorbing foam, not the kind commonly available, but the stuff noise engineers use for machine noise. [/size]

Thank you Mr. Noxon, Drums are too loud, but I love to play my drums in big churches, stages etc., I guess it's not only the intensity of the direct sound... Outside my room, playing the same cymbals and snare rimshots suddenly become a pleasure. I can measure the decibels of the drums with the sound level meter I will post some info later. I went for an hearing test yesterday, just to make sure ...(see below) Was very interesting to see the audiogram print out! I was disappointed, the curve is not flat! But the doctor said my ears are normal and in good health, they did various tests... 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... The doctor recommended a company that make musicians ear plugs $50 each, custom made based on the shape of my ears and the EQ I want :shock: the nurse said... interesting, will see. Anyways, for sure snare rim-shots and cymbals are not healthy stuff! (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,

arthur noxon wrote:

The problem with EQing the sound you are making is that you tend to want to correct for the deficiencies in what you are hearing. So if you use foam to EQ sound above 1k, then your drum kit will feel too heavy in the mids and bass and you will lighten up on the power you are delivering to the bass and toms. [/size][/size]

yes, sound definitely weird...

arthur noxon wrote:

It’s just like recording engineers. If they work in a room that is bass light (as in acoustic tile ceiling) then they will bring more bass into the mix and end up with a bass heavy record.

So my room is bass light already? ... Good news, I will use the corners too store some mic stands and equipment instead!

arthur noxon wrote:

The musician style ear plugs promote full range damping, all frequencies equally. That sounds nice at first but when the volume goes down, we lose sensitivity to the bass more than we loose sensitivity to the treble. That’s why we have to use bass boost when we turn the volume down. So we don’t want to turn the volume down a flat 20 dB. It has to slope some, 20 dB in the treble is OK but maybe only about 15 dB in the midrange and only 10 dB in the bass. See “Fletcher Munson curves”. [/size][/size]

Hopefully what the nurse said is true then ... if they can make earplugs that EQ to specific frequencies will be great.. I will definitely upgrade to musicians earplugs, I went there today for the mold but I got lost .. next appointment Monday. Still I hope to tune my room for rehearsals/ recordings with the band etc. I love my friends too... :) It's getting more difficult, my audiogram test curve , Fletcher Munson curve, my room curve etc.. So ... based on Fletcher Munson curves, the easiest tweak for my room will be to turn way down the 4000K and leave the rest untouched...?Interesting, my audiogram hearing test curve is similar to Fletcher Munson curves look!!...

Image not preserved: Fletcher Munson curves.gif

Image not preserved: z. musicians ear plugs hearX.JPG

Image not preserved: z. hearing test audiogram test small.jpg