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**MS-SPO** · 07-13-15, 03:21 PM

Hi gusvd,

welcome ;-)

(A) I think, unless we are able to compile a couple of Sound Pressure Level (SPL) based measuremenst in dB (decibels), all discussions will be incomplete and may tend to be more guesswork or wishful thinking.

I mean, even when Repeatability (by different people in different environments) and Reproduceability (same measurement at same noise insulating platform) (=Gauge R&R) should be bad, it's a start focused on data and facts.

(B) Trained listening, as Bob Katz proposes as the most valuable tool in his book "Mastering Audio" for producing audio of the highest quality, may be useful, but to my experience it's harder to compare different findings from different people just by describing "what I was listening to, and how it differs from an other listening". So the SPL meter will be a very useful tool for comparisions (class C, slow).

(C) You may have seen my report and calculations at http://www.vdrums.com/forum/advanced...f-the-platform .

To my understanding kicks and taps do disturb, because we create high energetic shock waves in gases (air) and solids (wall, floor, ceiling), i.e. short intense pulses in the time domain, which do correlate with a broad frequency spectrum in the frequency domain.

So far I haven't found good anti-measures against shockwaves, besides preventing them in the first place (or moving to a remote place, or to a bunker or so). The best technical solution I know about so far are ballistic vests. However, if you look at their structure, they have some layers of hard to destroy meshes by mechanical impact. They also tend to channel some energy to the perpendicular directions, and they dissipate some energy portion. In result, the vests DO catch the bullet, but DO NOT dampen the shock wave completely. You can tell this from the impact, the vicitm still feels under the vest, and the bruise that will stay for a while at his body.

D3O offers a special material ( https://www.google.de/search?q=d3o&t...ih=784&dpr=0.9 ) similar to a ballistic vest, but if you look at the percentages they publish in improvement AND convert them to decibels, they also only provide a few dB of dampening.

I estimate what we have to be after as drummes are dampening of platforms or noise insulators in the order of at least -30 dB SPL under drumming conditions (shock waves), where more is better. -30 dB SPL of dampening corresponds to a ratio of 1 : 32, which is 3 % remaining or less, or vice versa absorbing 97 % or more.

(D) Because it's a wave phenomenon we have to deal with, we'd need to apply and use phenomenons from wave physics, like diffraction, interference and so on - which will be tough to do on a broad frequency signal like a kick or a tap. (And which will probably explain, why a randomly ordered solid with variable density in space, like a concrete ceiling is, dampens drum created shock waves by about -10 dB SPL, as I stated from my measurements.)

Best regards, Michael

**FusiveR** · 07-13-15, 06:02 PM

How about the Roland NE10 under the BD and HH pedals? No DIY required but I hope your wallet is fat.

**MS-SPO** · 07-14-15, 02:04 AM

Originally posted by FusiveR

How about the Roland NE10 under the BD and HH pedals? No DIY required but I hope your wallet is fat.

It won't suffice:

"Checking Rolands brochure on NE-10 (for kick) and NE-1 (for rack) they indicate reduction by 75 %, which is sth. like 2.5 dB (i.e. less than 3 dB improvement). "Eating" would be different to me, sth. like 30 - 60 dB reduction.." (for kicks and hits, not for taps with sticks)

Cited from http://www.vdrums.com/forum/advanced...f-the-platform , post #3

Reference: Roland Noise Eaters: http://www.roland.com/products/ne-10/

**gusvd** · 07-15-15, 06:00 AM

Hi Michael,

Don't be so negative

But honestly I really appreciate your input. I have to say you brought the discussion to a level I have never thought of before. I'm not a very technical guy, but I understood that to stop the vibrations from being transferred to the floor completely it would take a lot of scientific researching in terms of materials and experimentation.

Since we don't have this at the moment I'd really like to find out what's available. On my research I even find a material that is supposed to be used underneath washing machines to reduce (not prevent completely) the vibrations that is transferred to the floor and subsequently the noise.

Those are the options I found so far:

- Auralex Platfoam + MDF + Green Glue (something like this: http://www.mikedolbear.com/story.asp?StoryID=3807)
This one also involves som DYI but it's a bit more simple. It consists of two MDF boards glued together using Green Glue and the Auralex Platform kit under the boards.

-Screedboard 28 (http://www.cellecta.co.uk/cellecta-b...or-insulation/)

- Quietfloor

airborne, impact noise soundproofing with quietfloor acoustic underlay

http://www.keepitquiet.co.uk/quietfloor-plus-acoustic-underlay/

quietfloor is a 15mm thick heavy, acoustic underlay to reduce airborne and impact noise through floors when used beneath carpets and laminate flooring

- Thomann Drum Noise Elimination Podium

Thomann Drum Noise Elimination Podium

http://www.thomann.de/gb/thomann_drum_noise_elimination_podium.htm

Platform for Decoupling Drums This podium eliminates the transmission frequencies that are generated when playing an electronic and acoustic drum set. This relieves the pressure on roommates and neighbours in particular, as they will no longer be...

Again, I'm not looking to eliminate the noise completely, but reduce it as much as I can.

Cheers,

Gustavo.

**ignotus** · 07-15-15, 06:41 AM

I have a platform made with this:
copopren.jpg
It's polyurethane foam. It's called 'Copopren' in Spain - sorry, I can't say where you could buy it but I'm sure there's an equivalent where you live - it looks similar to the Quietfloor stuff. They claim it reduces impact noise by 32 dB but we all know what to make of such claims... I have 2 layers of this (each layer 2 cm thick) alternated between 2 layers of gym mats - the stuff that comes in squares that you can join together. These foamy layers are in turn sandwiched between two 1 cm thick particle boards. All glued together and then carpeted. Quite easy to DIY. I don't have any fancy technical measurements to share other than those made by a spouse-o-meter located in an adjacent room:

Pre-platform spouse-o-meter reading: 'That thing makes an awful thudding noise, it sounds like there's an elephant kicking the wall - do something about it or it'll have to go".

Post-platform reading: 'What did you do? I can still hear some faint clackety noises but... Ok, it can stay'.

**MS-SPO** · 07-15-15, 08:25 AM

Hi gusvd, ignotus,

thank you for your reply and feedback ;-)

About metering I don't think it has to be scientific. Audio guru Bob Katz on one picture in his book holds something in his hand, while setting up an open air concert. It turns out to be the iphone application "Audio Tool", which costs just a few dollars. When it's good enough for Bob, it should be good enough for our purposes ;-)

Audio Tools: https://itunes.apple.com/de/app/audi...379146462?mt=8 and https://itunes.apple.com/de/app/audi...325307477?mt=8
Please make sure to dial C-weighted and slow, which seems to match with our human perception of loudness.

The alterntatives of course are more expensive, unless you can borrow it: https://www.google.com/search?q=soun...meter&tbm=shop (I was lucky to obtain a reduced price on one of these).

The spouse-o-meter isn't too bad at all. Your improvement sounds more like the 10 dB-range, than the 3 dB-range. Perhaps your spouse can compare your latest noise level? For reference, my bedroom at night is in the order of 35 dB SPL, while distant traffic with open window is about 50 - 55 dB and about 40 - 45 dB with window closed, and cars passing by in 15 m are about 60 - 65 dB with windows closed. (Crying into my ear directly will be about 100 dB.) So perhaps she can at least estimate which range it is in (e.g. "it's louder than at quiet night time, but not as loud as distant traffic with windows closed").

An alternative is to use some sound from your audio equipment, e.g. her favorite song, or even FM-noise from a detuned station, and use the volume dial. Just adjust the volume, so it matches her perception on average. Position 1 would indicate the loudest elephant before your improvement, position 2 the current residual noise from your improvement, and positon 3 the "best wish". As these dials work on a logarithmic scale, we can also compare distances (for linear sliders) or angles (for knobs to turn).

What we also need to take into account is our places geometry. Which means: in what kind of building do you play drums. E.g. mine is located on the 1st floor, with a concrete ceiling and a room underneath it. So noise transmission to the people below may differ from noise transmission through the walls (and may be from vibrating ground), when there are no rooms underneath or above, but just next to me.

More details soon. Best, Michael ;-)

**MS-SPO** · 07-15-15, 08:59 AM

Hi,

here's a quick test to check absorption of a material you can get a hand on, literally:

* put your ear on one side
* snip against the material with your finger on the other side (creating a shock)

If you can't hear anything, or if it's very silent, it's a good candidate.
If it sounds quite loud, say at mid frequencies (voices "ping"), it has its weaknesses. Same for loud low frequency sounds (bass '"plong") or loud high frequencies (trumpet, fluit etc. "plink").

I remember my layers sound loud at voice frequencies ... so I shouldn't wonder ...

If you can prefer material, which doesn't "ping", "plong" and 'plink" ;-)

Best, Michael

**ignotus** · 07-15-15, 09:07 AM

I think that what you say about the geometry of the location is key. I live on the top floor in a block of flats, the floor is wood over concrete and the room my kit is in has many wall-mounted storage cabinets, bookshelves and a large carpet in the centre. The biggest problem was the impact vibration of the bass drum travelling through the floor and walls and the platform reduced that to an acceptable level. The airborne noise of the pads is audible in the next room, and two rooms down it is barely audible. But if I were to remove all the furniture, books and carpets, I reckon the noise level would increase spectacularly. I also live in a town centre with a semi-permanent din from roadworks/traffic/construction work so noise from the exterior is almost always louder than the noise my kit will ever make, bar the kick drum thud before the platform. If you look at opinions on professional soundproofing solutions, even then, opinions vary widely, despite the fact that they are meant to have a "standard" impact on noise levels. So in the end it all comes down to your particular circumstances and expectations. Some people swear by the tennis ball platform and others say it barely made a difference... So even if you come up with a figure X for your noise-reduction solution, it might produce a wildly different result for someone else.

Therefore, though unscientific, I think the best way to provide a reference for someone looking for a solution is to say 'my kit is in X environment, I needed to bring down impact/airborne noise and Y went so far in solving my problem'.

**MS-SPO** · 07-15-15, 03:32 PM

Originally posted by ignotus

Therefore, though unscientific, I think the best way to provide a reference for someone looking for a solution is to say 'my kit is in X environment, I needed to bring down impact/airborne noise and Y went so far in solving my problem'.

Very good aspect, which I fully support.

I think it's good to back up by measurements, as I described earlier here. Even, when measurements deviate by some decibel, it's better than speculating or arguing, isn't it? Wouldn't it be nice if we can end up with some proven figures, even when they are not too accurate, ...
... to do better noise design as needed?

Because today everybody spends time and money separately, where some solutions may be very good, and other may be quite poor. That doesn't matter, we can learn from it.

E.g. let's take my measurements as an illustration. When my rack or kick brings 91 dB SPL into the floor, when I really get lost at the kit, and the concrete floor takes away about 10 dB SPL, then 81 dB SPL come from the ceiling in the room underneath. If 70 dB SPL are acceptable there (which is probably close to your town center room), then the floor insulation under my kit must absorb 81 - 70 = 11 dB SPL. How to do it reliably? When only 45 dB SPL can be tolerated (normal noise level at day time in my place with windows closed), my kit insulation needs to provide 81 - 45 = 36 dB SPL. How to do it? Then you, ignotus, have a certain wall-related issue. How to implement the dampening you need in your place?

I'd like to be able to answer these sort of questions. Best, backed up by measurments, e.g. from this community. Best, not taken from the glossy broshures of various suppliers. From a technical point of view this isn't even hard to do: we can obtain reasonable estimates from what people do have already, when they are willing to take some (many) measurements. (May be we need to compile typical noise-insulating requests, to gice some guidance for measurements and descriptions.)

So, there are a lot of design issues (room-floor-room propagation, room-wall-room propagation, in-flat propagation and so on). And physicist like me usually do some modelling in such case. "Modelling" can be quite simple or sophisticated; it's just a different word to describe what we have to a certain degree of certainty (or uncertainty).

Best, Michael

**MS-SPO** · 07-15-15, 03:38 PM

Originally posted by ignotus

I have a platform made with this:
[ATTACH]n1117873[/ATTACH]
It's polyurethane foam. It's called 'Copopren' in Spain - sorry, I can't say where you could buy ...

Hi ignotus,

I found Copopren here: http://www.isolplus.es/tienda-online...uelos?vmcchk=1

At the end of this page they provide some pdf-files, where they describe, how the obtain the dampening factors, and how they depend on frequency. In general, this material tends to PASS the low frequencies (i.e. dampens a little bit), and BLOCK higher frequencies. In my quick check test you'd probably hear a "plong"-er.

Anyway, it's an interesting material. However, we should have data from a drumming environment under drumming conditions.

Best, Michael

**MS-SPO** · 07-15-15, 03:50 PM