John Sayers' Recording Studio Design Forum Archive

Hi all,
So I am that guy in the apartment block with a saxophone.

I have been considering various noise dampening solutions. My goals are realistic, I don't need to silence the sax-just bring it down to TV level. I am not a ridiculously loud player. The apartments are well sealed from each other which gives me an advantage off the bat.
I saw the VocalBoothToGo soundproof-ish tents, and I was thinking something similar DIY on a budget - a very small budget - might be possible.

I know the basics and have been around studios etc for years, so I understand - its all about mass and sealed pockets of air.
What I am on about here is lowering the perceived volume outside the apartment. The word perceived is key here. So I am interested in to what extent you guys think that absorbing reflections is a useful thing in this situation.

So... Expensive high mass acoustic blankets are out of my price range. I was wondering if anyone has suggestions for cheap and semi-functional alternatives?

My current vision is getting some sort of material and constructing a tent pole frame and sewing a covering that would seal on the floor too... probably going to have to consider ventilation also...
All thoughts, suggestions and derision welcomed.
Cheers!

Hi there "The_Mentiad". Please read the forum rules for posting (click here). You seem to be missing a couple of things!

... soundproof-ish tents, ... My current vision is getting some sort of material and constructing a tent pole frame and sewing a covering that would seal on the floor too...

I'm afraid that I don't have very good news for you at all! You see, on the internet there's marketing hype, there's also myths and legends, there's even snake-oil... and then there's reality. Here's how reality works:

so I understand - its all about mass and sealed pockets of air.

So you already get the basics, and only need some numbers. Good.

As you correctly stated, isolation depends on mass. For a single-leaf isolation system, such as a tent, the equation that you need to use is called "mass law". Empirical mass law goes like this:

TL = 14.5*(LOG(M*0.205))+23 dB

Where "M" is the surface density.

Froam what I could find out with a quick Google search, canvas tents is graded in various ways, but the density is fairly easy to figure out. A common type typically used in light-weight tents is "8oz" canvas, which weighs in at the whoppingly small amount of 0.272 kg/m2. Yup. A little more than one quarter of a kilogram per square meter. Plug that into the equation, and a tent made from such canvas will give you roughly 4.9 dB of isolation. Considering that most people won't even notice a reduction of 3 dB in sound levels, and would say that there was no isolation at all, you can understand that 4.9 dB of isolation is, very literally "next to nothing at all". Barely even noticeable. Since a sax can produce anywhere between about 80 dBC(SPL) and 100 dBC (SPL), call it around 90 for typical playing. So a tent would bring that down to about 85 dB. That's still LOUD, in anybody's book. You need a change of at least 6 dB before most people will say "Yeah, I noticed that: it changed just a bit."

The highest density canvas you can get for tents (the kind used in large circus tents, and tents for other outdoor events) seems to be 16 oz canvas, which weighs in at about 0.543 kg/m2. Making a "sax tent" out of that stuff would get you around 9 dB of isolation. That's still in the range of "next to nothing". You'd still be well over 80 dB outside the tent, for typical playing, and still hitting over 90 for loud playing. For comparison, a typical house wall is about one hundred times better, at roughly 30 dB of isolation. (Yes, I do mean really "one hundred". 30 dB of isolation does indeed imply 100 times less intensity than 10 dB of isolation. The decibel scale is logarithmic, not linear).

So no, a tent is not going to cut it. Not even a very heavy tent.

So I am interested in to what extent you guys think that absorbing reflections is a useful thing in this situation.

Zero. Zilch. Nothing. Nada. Nope. Not a thing. Reflection filters are about as useless as a canvas tent. Actually, a canvas tent is far better than a reflection filter, and a canvas tent is pretty lousy!

By coincidence, just yesterday another forum member was asking about something similar: portable vocal booths. So I'll copy-and-paste what I said to him:

So called "portable vocal booths" (also known as "reflection filters") are not very effective at all. They give you maybe 1 or 2 dB of isolation, and "color" the sound, so that the frequency response is damaged in one way or another. They attenuate some of the high frequencies and high mids, don't do much for the low mids, and can even amplify the low end!

Sound on Sound magazine did a good review on them a couple of years ago, where they evaluated several different models from various manufacturers. But they didn't just do the typical "try them out in grandpa's living room and evaluate by ear". Rather, they tested them fully in a proper acoustic lab, to see how they really perform under controlled conditions, with actual measurement of the performance. The results are not very encouraging.

The article is here:

http://www.soundonsound.com/reviews/how ... cal-booths

So... Expensive high mass acoustic blankets are out of my price range.

Even those are pretty useless, to be very honest. They might be fine for reducing the level a bit around some machinery and some types of equipment, but not for musical instruments played loud.

You only get usable isolation from mass. You either needs lots of mass (dozens of kg/m2), or you need a pair of "leaves" with slightly lower mass and an air gap between them.

You can't beat the laws of physics.

Sorry.


- Stuart -

Thanks Stuart.
Your help is much appreciated. I think we can rather safely say that the practice tent thing is scrapped.

But what about building a practice box within the room out of isolation board such as the Kingspan boards?
What do you think?

This stuff:
https://m.finn.no/bap/forsale/ad.html?finnkode=85346680

I was thinking maybe I could gaffer up some sort of box, with matting on the floor... I might need a fan...
What is your critique of that idea?

Cheers for all of this
Daniel

I perhaps should also note that I realise this sort of stuff probably sucks for cutting lower frequencies. But with the saxophone its basically treble I am interested in, no really bass, so I am hoping to be able to use that to my advantage in finding an easier solution.

But what about building a practice box within the room out of isolation board such as the Kingspan boards?
What do you think?

This stuff:...

Unfortunately, I don't speak Norwegian! So I could not understand the specs. But basically any building material that is reasonably massive will do the job. Things like plywood, MDF, and OSB would be good.

I was thinking maybe I could gaffer up some sort of box, with matting on the floor... I might need a fan...
What is your critique of that idea?

That's pretty much the concept for an isolation booth! Just a simple wood frame with plywood, MDF or OSB on one side, and filled with insulation on the other side, plus a fabric cover and some wood slats to liven things up... That's the concept.


- Stuart -