Archive for category Home Entertainment

Demystifying Acoustic Data: Part 2 – Test Material Mounting

For anyone new to the world of acoustics, there is a multitude of terms, coefficients and numbers that are thrown around.  This flood of information can seem intimidating, especially to beginners. In this series, acoustician Cameron Girard of Acoustics First® hopes to help you distinguish between what’s useful and what’s not.

Part 2: How Mounting in Testing Affects Sound Absorption Data

As I discussed in my previous article, the best way to compare the performance of sound absorbing panels is by referencing the Sound Absorption Coefficient (SAC) and Noise Reduction Coefficient (NRC). However, these coefficients are often used as marketing tools. Be on the lookout for companies that list absorption coefficients and NRCs without mention of a particular testing standard or mounting method. It’s vital to check for this information, as direct comparisons to competitors and other materials can only be made if their testing procedures are the same.

The sound absorption of a material that covers a flat surface not only depends on the physical qualities of the material but also on how the material is mounted during installation. The mountings specified in laboratory tests are intended to simulate conditions that exist in normal use, such as direct wall mounting and installation into a ceiling grid.

Many materials for treatment of walls or ceiling are tested using what is called Type ”A” mounting. Type ”A” mounting means the test specimen was placed directly on the test surface of the reverberation chamber. Lay-in ceiling tiles, on the other hand, are often tested using ”E400” mounting. The ”E” designates a sealed air space behind the specimen (simulating  the air gap between a dropped tile ceiling and the structural ceiling) and the number after the ”E” is the depth of the airspace in millimeters. The airspace behind the acoustic material affects the sound absorption by acting as a bass trap. The deeper the cavity behind the panels is, the lower the fundamental of the “trapped” frequencies will be.

To see what this look like in terms of actual numbers, let’s take a look at how different mounting methods effect the sound absorption coefficients of Acoustics First’s HiPer® Panel (a low-profile, composite absorber/diffuser panel).

Since the HiPer® Panel can be used effectively in multiple applications; we had it tested in accordance to the two most-common mounting procedures, Type E-400 and Type A. The results of the laboratory tests are as follows:

Product Info

Sound Absorption Coefficients

Product Name Thickness Mounting 125Hz 250Hz 500Hz 1kHz 2kHz 4kHz

NRC

1″ HiPer® Panel 1″ E-400 0.43 0.28 0.51 0.76 0.99 1.10 0.65
1″ HiPer® Panel 1″ A 0.09 0.28 0.78 0.75 0.94 0.85 0.70

 

As you can see from the chart, the sound absorption coefficient at 125 Hz varies greatly between E-400 mounting (SAC of .43) and Type-A mounting (SAC of .09). If mounting the HiPer® Panel in a ceiling grid, with a sizable airspace, you can expect significant low-frequency absorption, but mounting it on a wall (Type-A) will result in much less absorption at 125Hz.

Other mounting methods are available, but are not used as frequently. Here are some of the basic mounting designations (See ASTM E795 for more information.)

Type A mounting – Test specimen laid directly against the test surface (wall panel on drywall).

Type B mounting – Test specimen cemented directly against the test surface. Type B mounting is intended to simulate acoustical ceiling tiles or other sound-absorptive products adhered to a hard surface with an adhesive.

Type C Mounting—Test specimen comprising sound-absorptive material behind a perforated, expanded, open facing or other porous material.

Type D Mounting—Test specimen mounted on wood furring strips.

Type E Mounting—Test specimen mounted with an air space behind it (dropped tile ceiling).

As we’ve discussed, acoustical data can vary greatly depending on the mounting method used during testing. Acoustics First tries to include as much information about testing procedures as possible, because we feel an informed client makes the best client.

Contact Acoustics First for your all your sound control needs!

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DIY – Back Wall Diffuser Array/Bass Trap: Revisited

DIY - Diffuser Array/Bass Trap

DIY – Diffuser Array/Bass Trap

bass trap foam diffuser - sideThis month we thought we’d share a few Real-Life pictures of an idea we first introduced back in summer of 2013: The “Back Wall Diffuser Array/Bass Trap”.

Isolation Hanger

Isolation Hanger

This is the DIY project which incorporates our Art Diffusors®, Cutting Wedge® foam and a couple of isolation hangers into one large free-floating unit, which is acoustically decoupled from the wall.

This particular array was put together by a music producer/bass player for his home. As you can tell from the pics, the construction of this unit was executed beautifully and it’s very close to the original concept drawings.

It’s never too late to get started on your own DIY project.

Real World - DIY

Real World – DIY

Visit the Original DIY page to find out how to make your own. 

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Acoustic Treatment for your Home Theater or Listening Room

Any good theater or listening is acoustically treated to ensure the sound coming from the speakers is what arrives at the listener’s ears. Conditions common in small/medium rooms, such as flutter echo and comb filtering, degrade the clarity of music and speech. Here are some tricks to get a full and accurate sound out of your home theater or listening room. For those visually inclined individuals, the accompanying video shows how a critical listening space would ideally be treated.

Bass Traps – low-end control
Low frequency problems are common to almost any room, regardless of size.  The good news is that most of the time the solution is simple. By installing bass traps in the corners of the room you can prevent the excessive bass build-up. If bass frequencies are allowed to build in the corners, it causes the bass frequencies to become muddy and undefined. The more corners you cover with a good trap, the better bass response you get from the room.

Having bass traps in all corners is best. That said, if you only have budget for two, having bass traps in the front corners of the room should be the highest priority. Fabric wrapped absorbers look as good as they sound, and Geometrix™ by Acoustics First, fit the corners like a glove.

Broadband Absorption – tame the ring.
To control the flutter echo caused by reflective parallel walls, it’s vital that the first refection points are treated with broadband absorption (wall panels). More than likely, your TV and/or sound system is in a fixed position, and your listening position will be relatively fixed as well. This should make the early reflection surfaces easy to locate. Sound travels in all directions from the speaker, including behind it, so put absorbers behind it on the wall. Don’t forget the floors, ceiling, and the wall behind you – sound will bounce off those as well.

Hang broadband absorbers over all the early reflection points – left, right, front and back so they are centered at ear height.  Placement is the first key to getting this reflection free zone.  The second is the right choice of absorber. To match your fabric wrapped bass traps, the simple choice is get some more panels wrapped in fabric. The Sonora® line of broadband absorbing panels coordinate with the bass traps, and come in a plethora of sizes and mounting options to work in your space.

Diffusers – put life back into your space.
Diffusion will give us something we couldn’t attain through absorption – a sense of open space.  Even after treating with absorbers, there are still areas of the room where sound waves will sit, because your room is a fixed box with fixed speakers.  Diffusers scatter the energy, creating ambiance with residual energy. This simple step does not remove energy from your room, but redistributes it into a soundscape that can make you forget you are in a room at all. In order of priority, the rear walls, front wall and ceiling are the most important surfaces to install diffusers.

There are many ways to diffuse the sound and coordinate with your room, from the fabric covered HiPer™ Panel and Double Duty Diffusers™, to the striking line of Art Diffusors® like the Model C, which can be painted to match your décor.

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DIY – Treating a Wall – BlockAid® and SoundChannels®

AcousticsFirstOn many occasions, we get asked about common ways to treat a wall (or walls) either for broadcast, podcast, or other voice recording scenario – where they not only want to tame the reflections within the room, but also block a certain amount of sound coming into – or leaving the room.

Budget is frequently an issue, major construction is usually unwanted, but effective results are always required.

We’re going to show you how to handle a room upgrade – cut down on the sound transmission and cut the room reflections – all with the same skills required to hang high quality wall coverings!  Let’s see how you can cover a wall with BlockAid® vinyl sound barrier to block unwanted sound, then go back and cover that with an absorptive layer of Sound Channels® wall covering  to finish it off!

This treatment is not recommended for renters, as this is not an easy upgrade to undo.  However, if you have an extra bedroom you are using as Podcast studio, this is a great way to treat it… Let’s get started!

Installing BlockAid®

Measure the wall for the first panel length. Mark the panel width on the wall.

1. Measure the wall for the first panel length. Mark the panel width on the wall.

Measure and Mark the length of the wall on the BlockAid®

2. Measure and Mark the length of the wall on the BlockAid®

Use a straightedge and a razor to cut the BlockAid® to length.

3. Use a straightedge and a razor to cut the BlockAid®.

Using a trowel, apply vinyl tread adhesive to the wall, covering the whole area where the first panel is going. (You marked the wall right?)

4. Using a trowel, apply vinyl tread adhesive to the wall, covering the whole area where the first panel is going. (You marked the wall right?)

Hang the panel starting at the top, install a few screws to hold it in place while the adhesive sets. (You will probably need a friend to help, as BlockAid® is a pound per square foot!)

5. Hang the panel starting at the top, install a few screws to hold it in place while the adhesive sets. (You will probably need a friend to help, as BlockAid® is a pound per square foot!)

Using your hands and a putty knife, smooth out all the air bubbles from behind the BLockaid® so that you get a good bond when the adhesive cures.

6. Using your hands and a putty knife, smooth out all the air bubbles from behind the BlockAid® so that you get a good bond when the adhesive cures.

Repeat the steps for the next strip. Measure, Mark, Cut, Trowl, Hang...

7. Repeat the steps for the next strip. Measure, Mark, Cut, Trowl, Hang…

Make sure you line up those seams! push them right up agaist each other. Smooth out the air bubbles, cut out any outles, trim any extra... Let dry!

8. Make sure you line up those seams! push them right up agaist each other. Smooth out the air bubbles, cut out any outles, trim any extra… Let dry!

Good job! Now, take a breather while that dries, and notice how much less sound is passing through the walls.  This is when you will notice that the sounds are now coming from under the door, and through the leaky old window.  These can be taken care of in different ways…. but the easiest way is the same way you deal with keeping the cold out!   Get some weather strip, a door skirt, seal the gaps around the frame of the door, and windows, maybe go out and buy some heavy curtains for the windows… if you have some leftover BlockAid®, you can always get some Industrial Velcro and temporarily stick a piece over the window!

Installing Sound Channels®

1. Remove the Screws from the BLockAid® - if you didn't already... then same as BlockAid®, measure the wall, mark it, measure and cut a piece of Sound Channels® and start troweling on the Chapco!

1. Remove the Screws from the BLockAid® – if you didn’t already… then same as BlockAid®, measure the wall, mark it, measure and cut a piece of Sound Channels® and start troweling on the Chapco!

2. Well, when you get tired, make your friend finish troweling out the adhesive to cover where the panel is going. (You are going to overlap the seams.)

2. Well, when you get tired, make your friend finish troweling out the adhesive to cover where the panel is going. (You are going to overlap the seams.)

3. Starting at the top, hang the Sound Channels® overlapping the seam of the BlockAid under it. Smooth out the air bubbles with your hands. Make sure it lines up well. No screws needed!

3. Starting at the top, hang the Sound Channels® overlapping the seam of the BlockAid® under it. Smooth out the air bubbles with your hands. Make sure it lines up well. No screws needed!

4. Measure and cut the next strip, carefully following a rib in the fabric, while your friend, (who is way better at troweling than you are anyway,) preps the next section with adhesive.

4. Measure and cut the next strip, carefully following a rib in the fabric, while your friend, (who is way better at troweling than you are anyway,) preps the next section with adhesive.

5. Best practice is to run the fabric in the same direction every time. Not just with the ribs, but in the same direction it comes off the roll. So find the top.

5. Best practice is to run the fabric in the same direction every time. Not just with the ribs, but in the same direction it comes off the roll. So find the top.

6. After you find the top, start hanging from the top, lining up the seams and smoothing out the bubbles as you go.

6. After you find the top, start hanging from the top, lining up the seams and smoothing out the bubbles as you go.

7. Keep those seams tight as you go. Keep smoothing... almost done!

7. Keep those seams tight as you go. Keep smoothing… almost done!

8. Trim up the extra and repeat as many times as needed.

8. Trim up the extra and repeat as many times as needed.

That’s it!

Don't forget to trim around those outlets!

Don’t forget to trim around those outlets!

This treatment is a common first step in treating many professional broadcast studios – it gives you extra isolation with the barrier and takes the edge of the sound reflections.  Many professional environments then go back and add some additional treatments such as bass traps, diffusers, and broadband absorber panels – especially if these studios are planning on bringing in any musical guests.

This isn’t just for home studios.  It works great for kids play rooms, bedrooms, home theaters, home gyms, and any place you want to block sound and tame the sound inside the room.

Customize your space as you will, but this treatment is a consistent winner for cost and performance, and is a great way to get started without breaking the bank!

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Season’s Greetings from Acoustics First – 2014

Season’s Greetings from Acoustics First!

DIY Gift idea using Tone Tiles

DIY Gift idea using Tone Tiles™ and some Creativity!

Acoustics First would like to offer this Do-It-Yourself gift idea to all of our readers this year.

If you’ve got a creative painting habit, give a customized gift that not only shows your creative talents, but also helps to improve the sound of the room!

Above is a festive holiday painting on one of our 1’x2′ Tone Tiles™.

Want to go a little bigger?  We also have 2’x3′ Tone Tiles™ in Stock.

Amsterdam iPhone photo

2′ x 3′ panel  Photo from iPhone

 

A Second Idea is to get a photo printed on a Tone Tile™.

Got a really great vacation photo or family photo on your phone?  Most phones today have pretty decent cameras, and if you have the right photo, a local printer may be near you that can clean it up and print it onto one of our Tone Tiles™.*

How about “posting” that photo to the “wall” of your living room, and have a great conversation piece as well as improved acoustics – at the same time !

 

 

Season’s Greetings and Happy Gift Giving!

– Acoustics First

* Don’t forget to ask your local printer if they have flatbed printing capabilities.

 

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