How effective are moving blankets for sound deadening?

Description

They're cheap but are they effective? Today at the House of Hacks, Harley investigates if it makes sense to use moving blankets for acoustic treatment. People have tried different sound absorption techniques to remove room echo from recording spaces. Acoustic foam panels and a sound blanket are two popular items. Moving blankets appear similar to sound blankets and are considered DIY sound absorption materials, but how well do they work in a recording studio for sound absorption? Today we're going to measure the difference between having them and not having them actually makes.

Affiliate links:
12 Moving blankets
1 Real acoustic blanket

Resources:
How to measure echo in a room

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For a written transcript, go to Workshop Organization Systems - Quick and easy overhead bins

Music under Creative Commons License By Attribution 3.0 by Kevin MacLeod at http://incompetech.com.
Intro/Exit: Hot Swing

Transcript

[Door bell]

Oh, FedEx. Thanks!

Do you need to reduce echo in a room for recording?

Today, we're going to look at these moving blankets and measure how well they actually work for this application.

[Introduction]

Hi! Harley here.

I'm down here in the workshop which is in the unfinished portion of our basement.

It's got concrete walls, concrete floors, and from this app we can see we've got 0.65 seconds of decay time.

To try to get that down, I got some moving blankets from Amazon, very cheap, and I want to see if this is actually going to make a difference in the echo in this space where I can hang them from the ceiling, drape them around the workshop, as I'm recording to try to get the echo down.

Let's open it up and give it a try.

[Opening package]

There are twelve blankets for less than $60 from Amazon.

I'll leave a link in the description below.

By comparison, you can get an acoustic blanket that's marketed as such for $75 for just one.

But the question is: does this inexpensive option really make a difference?

I haven't spent the money to compare the difference between the moving blankets and the one that's really designed for the purpose, but I can compare the difference between with and without these moving blankets.

First, I installed an application on my phone to actually measure the echo.

And as we saw in the opening, without the blankets, the echo is 0.65 seconds.

I'm going to use some spring clamps to hang the blankets around the workshop.

[Hanging and draping blankets]

So, I'm really impressed!

Depending on the test, it was between 0.19 and 0.43 [sic] seconds delay after adding the blankets.

That's between...

...about a third on the high end and not quite half on the higher end.

So, yeah, these blankets really do make a difference.

How that compares to an acoustic blanket? I don't know.

I'm not going to spend that much money, but they do make a difference.

That's a good thing.

I'll certainly be using these in the future when I'm recording to reduce the echo in here.

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If yours leans towards marking things and you're interested in future House of Hacks workshop related videos, hit the round House of Hacks icon over there and then hit the bell notification and YouTube will let you know next time I upload something.

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Thanks for joining me on this creative journey.

Until next time, go make something.

Perfection's not required. Fun is!

Six tips to more accurate measurements in the workshop

Description

Accurate measuring in the workshop can be critical to the success of a project. In this episode of House of Hacks, Harley presents six tips on how to make more accurate measurements.

Amazon associates list containing items discussed: Pencil sharpener, Mechanical pencil, Retractable Sharpie, X-Acto knife, Caliper

Subscribe for more DIY videos.

Watch my most recent video.

For a written transcript, go to Six tips to more accurate measurements in the workshop

Music under Creative Commons License By Attribution 3.0.
Intro/Exit: "Hot Swing" by Kevin MacLeod at http://incompetech.com

Transcript

Coming soon.

How to measure fluorescent and LED light flicker

Description

Fluorescent tubes flicker because of their inherent design. LED lights may or may not flicker depending on how well their power supply is designed. How do you measure the amount of flicker? In this episode, we quantify the flicker in the fluorescent tubes and after an LED light conversion.

How to easily convert fluorescent tubes to LEDs: https://www.youtube.com/watch?v=_YROz2AekkA
Electronupdate video: Measuring Light Bulb Flicker with Nothing More Than a Cell Phone: https://www.youtube.com/watch?v=Qym5-126BDY

For a written transcript, go to How to measure fluorescent and LED light flicker

Music under Creative Commons License By Attribution 3.0.
Intro/Exit: "Hot Swing" by Kevin MacLeod at http://incompetech.com

Transcript

After seeing last week's episode about converting fluorescent lights to LEDs, David Terry asked "do they flicker the same way fluorescent tubes do?” I wasn’t sure, so let's measure and find out, today at the House of Hacks.

[Music]

Hi Makers, Builders and Do-it-yourselfers. Harley here.

Fluorescent tubes are powered by AC current and flicker based on the speed of the power cycles. Here in the United States, our power cycles at 60 hertz. This means the hot lead varies between positive voltage and negative voltage 60 times a second. The tubes don’t really care about positive or negative values, just the absolute value and so will flicker at twice that rate, or 120 times a second.

This is too fast to bother most people, but a non-trivial segment of the population are affected by this and have problems working under fluorescent lights. The flicker can also cause artifacts when shooting video at certain frame rates. And, as the bulbs age, they may not go on and off at every cycle, causing the flicker to slow down and become more noticeable.

To measure the flicker, I've got this simple setup. I have just a solar cell and the oscilloscope. The flicker in the lights will cause the output of the solar cell to oscillate in sync and the scope allows us to see that variation. At 120 times a second, we expect to see each cycle to be around 8 milliseconds so I have the scope set to 10 ms per division.

Now I'm going to connect the scope to the scope to the solar panel. And we’ll see what we have here… and that's exactly what we expect to see; each cycle is about 8 milliseconds.

So now I'll go over into the room other room and check it out with the LEDs.

I still have exactly the same setup as I had before. Let’s connect the scope to the solar panel and see what we get.

Ah, a straight line. So, to answer David’s question: no, there is no flicker with these LEDs. Thanks David for asking the question.

And coincidentally, a couple days ago an electronics channel I subscribe to, electronupdate, uploaded a video showing how you can use a cell phone to detect this flicker. I thought you might find that interesting.

If this is your first time here at House of Hacks: Welcome, I’m glad you’re here. We’d love to have you subscribe. Through this channel I hope to inspire, educate and inform makers in their creative endeavors. Usually this involves various physical media like wood, metal, electronics, photographs and other similar types of materials. If this sounds interesting to you, go ahead and subscribe and I’ll see you again in the next video.

Thanks for joining me on our creative journey. Now, go make something. It doesn’t have to be perfect, just have fun!

How to quiet a shop vac - efficiency measurements

Description

How well did Harley meet his goals by setting up the shop vac to be a centralized system? In this episode, the changes are quantified with measurements for noise, vacuum and air flow.

Related videos:

• How to quiet a shop vac
• How to make a vacuum (or pressure) gauge

For a written transcript, go to How to quiet a shop vac - efficiency measurements

Music and sound effects under Creative Commons License By Attribution 3.0 or 4.0.
Intro/Exit: "Hot Swing" by Kevin MacLeod at http://incompetech.com
Light switch effect: http://freesound.org/people/AlienXXX/sounds/151347/

Transcript

Today at the House of Hacks we compare some efficiency parameters of the shop vac's original configuration and its new one.

[Music]

In this earlier episode, I presented some problems I had using my shop vac, some goals I wanted to meet by reconfiguring how I use it and how I actually made some of the changes. In this episode I want to show some of the before and after measurements to see what actually changed.

To recap, my goals were to 1) have minimal daily setup; 2) be convenient to use; 3) be much quieter; 4) and all this at minimal cost. I attempted to do this by converting it to a DIY central vac system.

Today I am going to show how well I accomplished my goals. I’ll show what it takes to use the new configuration, a couple specifications between the old and new systems: the loudness, the vacuum pressure and the air flow.

Overall I’m really pleased with the ease of operation. I typically just leave everything plugged in, setup and ready to go. All I need to do is grab the hose and press the power button. Of course if I’m working on a piece of equipment, I have to do some setup, but that is pretty minimal. I just move the hose to the closest outlet and connect to the equipment.

One of the goals was noise reduction. I used a freely available decibel app on my tablet to measure the noise levels. Admittedly this is an uncalibrated device and won't give exact results, but it does give a good idea as to relative differences.

In the shop, the vacuum runs around 85 db.

And when it's outside the box on the other side of the wall, it runs about 70 db.

When it's inside the box I made for it, it drops down to about 62-63 db.

Overall a reduction of over 20 db. Quite a bit. For comparison purposes, that's like going from being next to a food blender to being in an office.

A side effect of adding the plumbing is reduced efficiency of the vacuum pressure and air flow. Devices are available to measure these parameters accurately, but they're not cheap and I was more interested in relative loss, so I hacked together a couple instruments.

First vacuum. This is a simple DIY vacuum gauge that I made out of a simple loop of vinyl tubing, some water and a ruler. I explained how I made it in this other video over here. One end is open to the atmosphere and the other is connected to our vacuum. The difference in water levels tells us how much vacuum is being generated.

As you can see, we’re getting about 38, 39 inches of water here. And I'll consider this 100% of baseline for what the vacuum is capable generating, for comparison in future measurements.

Connected to the first port it reads 31.5 inches.

Connected to the second port it reads 32 inches.

Connected to the third port it reads 31 inches.

So, the ports have a reading of about 31.5 inches of water on average or a loss of about 20%.

To measure air flow, I picked up an inexpensive anemometer off Amazon.

Connected directly to the shop vac, this reads as an overload. The vacuum is advertised as 150 mph, but I suspect, based on the noise of the anemometer, that it’s not really that fast. For the purposes of this test I’ll estimate this to be about 110 miles per hour (MPH). Like before, this will be the 100% baseline for the other measurements.

Connected to the first port it reads 89 mph.

Connected to the second port it reads 88.5 mph.

Connected to the third port it reads 86 mph.

So, on average, the ports read 87.8 mph or a loss of about 20%.

While there's a loss of 20% in both vacuum and air flow, in practical application, I don't really notice any difference. It still picks up about what I need it to in about the same way.

In summary, I'm really pleased with the new setup. It's much easier to work with so I'm more diligent at keeping things cleaner.

In conclusion, I’d love to hear in the comments below what you think about vacuums versus dust collectors as a means of keeping the shop clean.

If this is your first time here at House of Hacks: Welcome, glad you’re here. We’d love to have you subscribe. Through these videos I hope to inspire, educate and inform makers in their creative endeavors. Usually this involves various physical media like wood, metal, electronics, photographs and other similar materials. Thanks for letting me encourage your creativity. So subscribe and I’ll see you again in the next video.

Now, go make something. It doesn’t have to be perfect, just have fun!