The Latest News on Acoustic Speaker Cloth – and Us

Category: Tipps und Tricks (Page 1 of 2)

A Living Room for Perfect Listening Pleasure

It doesn’t happen too often that people decide to optimize the acoustics of their living room. But true audiophiles are of a special breed. Marcel from Almere in the Netherlands is one of them.

Marcel and his wife designed the room interior and commissioned Mutrox, a renowned Dutch acoustics specialist and studio builder, to develop and deliver the required acoustically active elements.

The main goal was to acoustically optimise the room while retaining the look and feel like a living room. The second and more demanding aim was to provide the opportunity to adjust the reverberation of the room, in this way giving the residents the opportunity to fine-tune the room acoustics at their discretion whenever they like.

Marcel and his wife finally opted for the use of false walls, acoustic curtains, and an acoustically active suspended ceiling. While the suspended ceiling is fixed due to the limited height of the room, the side walls and the front wall are made of various movable boxes that contain acoustically active elements such as absorbers and panel resonators.

Absorbers behind acoustic cloth from Akustikstoff.com

These boxes, as well as the suspended ceiling, are covered with acoustic cloth from Akustikstoff.com

suspended ceiling with absorber covered with acoustic cloth from Akustikstoff.com

Individual wall sections were also clad with strategically placed strips of wood, which meet the aesthetic criteria of the residents and also work as diffusors. »They render more ambience to the room. We find wood a great product to work with, it has character and it benefits the sound«, explains Marcel.

Acoustic cloth from Akustikstoff.com and wooden diffusors in living room

With a base reverberation of 0.41 seconds and a rather natural decay as well as with an almost linear frequency response with a slight dip around 55 Hz and a peak around 130Hz, the optimised living room boasts next to neutral audio reproduction with great balance, focus, and range of audibility. It perfectly suits the requirements for high-quality audio reproduction.

Acoustic cloth from Akustikstoff.com on living room walls

»It was a lot of work and we did it all ourselves. After all, the effort paid off: The room looks cosy and it’s nice to be in there«, says Marcel. »We are satisfied with the fabric. It was great to work with, has a fine-meshed structure, and, as you can see in the pictures, it looks fantastic when installed. I highly recommend it.«

living room with acoustic cloth from Akustikstoff.com

Tape Magic

How to use our self-adhesive hook fastener tape

A couple of days ago we received an email from Casper, a customer from Denmark: »Shouldn’t the fixing tape I received consist of two parts – one for the fabric and one for the cabinet?« To get straight to the point, his assumption was wrong. But Casper was completely happy with the product after we’d emailed him a few explanatory lines and a link to our video tutorial. So, what’s the secret of our fastening tape?

Just like Casper, most people are under the false impression that hook fastener tapes always consist of two components, a strip with tiny hooks and another one with soft loops. This is true indeed for the classic »velcro« as we know it from numerous everyday applications, which is called a »hook and loop fastener« (there’s even a lengthy article on Wikipedia for those who are interested). In our case, however, you won’t find a single hook under the magnifying glass. Have a look at the closeup photo and you’ll find that the upper side of the fixation tape is covered with small stalks that have a mushroom-like top.

Akustikstoff Pilzband Nahaufnahme

To mount the speaker cloth, simply press the fabric onto the tape. Best protect your fingers with a robust glove or use something like a wallpaper roller, as the little heads are quite hard and edgy. They will penetrate the mesh and keep the speaker fabric in place tightly. Our video tutorial on Youtube provides you with more detail.

Mounting speaker cloth

The great advantage of this mounting method is that the speaker cloth can be detached again if you ever feel like giving it a wash or replacing it with a new piece of Acoustic Cloth in another colour.

Spray Adhesive as a Problem Solver

Many hifi enthusiasts have developed a great passion for the DIY refurbishment of vintage speaker cabinets. An update of the speaker grille with new Acoustic Cloth is one of the key elements in most of these projects, but it’s not always the easiest task. 

The JBL* LX55, for instance, a popular speaker among experts that is sold at increasingly high prices today, has a plastic frame with a relatively small edge to which the original speaker cloth is attached to. Moreover, the slot between the frame and the cabinet is extremely narrow. This construction makes it impossible to staple the speaker fabric to the frame (the method of choice with wooden frames) or to use of hook fastener tape instead. 

This is where our special spray adhesive comes into play. The adjustable nozzle of the container ensures convenient and economical application of the adhesive without any scattered spray mist and the high immediate adhesion of the adhesive provides for the easy and precise mounting of our sound-transparent fabric on such frames. It’s the perfect solution whenever you want to make speakers with plastic frames look like new.

JBL-LX-55-with-Akustikstoff-speaker-coth

»Your adhesive is really good for mounting fabrics. Very easy to use, no spill, and good adhesion. I used it for my JBL LX55 speakers with your grey cloth (colour code 14). I also refurbished a pair of Bose* 601 series 1 speakers with your beige fabric this year and I am perfectly happy with the result«, wrote Emmanuel D. from Digoin in France as he proudly sent us some photos of his speaker refurbishment projects. 

JBL-LX-55-and-Bose-601-refurbished -with-Akustikstoff-speaker-fabric

*All brand names are registered trademarks of their respective owners and are not in any way associated with Akustikstoff.com. 

DIY Embellishment: Covering AV Furniture With Acoustic Cloth

Sometimes it’s the little things that make small rooms look friendlier, less cluttered, and more attractive. That’s why it is a good idea to cover the often small-sized compartments of an AV rack in such a room with Acoustic Fabric in a matching colour. The immediate effect is that the entire room appears more straightforward and comfy.

Making such a cover doesn’t require any distinct DIY skills. All you need to build is an accurately fitting wooden frame with a hinge and a magnetic catch. Cover this frame with an appropriately sized piece of Akustikstoff.com Speaker Cloth (watch the tutorials on Youtube for details) and you’re done. The Acoustic Cloth lets infrared signals pass easily, so remote controls for receivers, amplifiers, etc. will work through the closed front, while all equipment along with the centre speaker or a soundbar remain hidden – as well as the countless little thingies that inevitably tend to accumulate in such a shelf over time.

DIY project with speaker cloth from Akustikstoff.com

A nice example is the AV-shelf our customer Nicolas T. from Joinville le Pont in France DIYed lately with Akustikstoff.com Standard Speaker Cloth. He kindly emailed us some photos of his project for this blog.

Simply Great: Individual Speaker Cloth Pre-Cuts

Speaker cloth laser pre cuts by Akustikstoff.com.

Quiz question: What does our boss present in this photo? A new, even more sound-transparent speaker fabric? Nice try, but not even close! Such grids remain when we produce individual pre-cuts of our speaker cloth.
Manufacturers of consumer electronics, AV furniture, vehicle components, and even slot machines are increasingly relying on such laser-cut pieces of our speaker fabrics produced exactly to provided standard CAD data.
As required MOQs are extremely small and lead times are next to none, Akustikstoff.com pre-cuts are also worth thinking about for companies that only produce very short production runs: Any tedious – and in most cases little precise – cutting of the fabric on the shop floor is eliminated, the pre-cuts can be processed immediately. On request, we can even “engrave” the speaker fabric, for example with a product name or a company logo.

Speaker cloth pre-cuts by Akustikstoff.com

Acoustic Cloth 2.0 – Dustproof? Oh Yes!

It all started with an enquiry from Nevada: A customer wanted to know whether our acoustic fabric would be dustproof enough to protect a couple of Bose F1 Arrays from exposure to dust during this year’s Burning Man festival. Good question. We didn’t have any  empirical data, as we’d usually focus on sound permeability and translucence (or rather the opposite) in the development of our speaker fabrics. But the question piqued our curiosity and we wanted to come up with a proper solution. We decided to use superfine flour as an imitation of the dust in Black Rock Desert. Not the worst idea: Marc-Antoine from Nevada replied that “superfine wheat flour is a good approximation of Burning Man’s dust.”

Our DIY test setup for dustproofness test of Acoustic Cloth 2.0 from Akustikstoff.comThe core of our test setup consisted of a piece of our stain-resistant and water-repellent Acoustic Cloth 2.0, an empty cardboard box, and  a DIY “flour cannon” made of a cardboard roll core and several bits and pieces. We pointed the “cannon” to the speaker cloth at a distance of about 20 cm. Dried pressurised air at about 80 psi from our workshop was used to propel the flour towards the fabric. The measured air speed (and, consequently, the exit velocity of the flour) at a distance of about 10 cm from the cardboard tube was 27 knots (which equals 50 km/h or wind force 6). Not bad, eh?

We wasted the first pack of flour to find that one layer of fabric isn’t sufficient in our view. We weren’t happy with the amount of flour that went through. So we modified the setup and attached two layers of fabric. The distance between the two layers was about 1.5 inches and the frame with the first layer was slightly tilted to prevent the flour particles from building up between the two layers and instead simply drop to the ground. Admittedly a somewhat shaky impromptu installation that wouldn’t meet the requirements for whatever ISO certification, but good enough for our purposes.

dustproofness of Acoustic Cloth 2.0 from Akustikstoff.com proven with a testThe result of this second round made us happy, as there were only very few particles still going through the two layers of speaker fabric. We found just a little dust on the ground of the box, after we’d propelled another full pack of flour towards the front of the construction and finally cleaned both with an air nozzle before opening the box.

We’ve uploaded a video of this test on Youtube, so why not have 90 seconds of fun, watch this bonkers and weird dustproofness test, and judge for yourself.

Acoustic Cloth Samples: Why They Make So Much Sense

Every week we receive a considerable number of emails that go like “I’ve seen a photo of this and that piece of furniture on your blog. What is the colour of the acoustic fabric?” If you’re about to drop us a similar email, please hang on for a sec and read the following lines first.

As we know where the photos come from (we have many customers who send us photos of their pieces of work and are happy to see them featured on our blog), it’s easy for us to answer such questions precisely. However, the answer could be pretty useless anyway.

The problem is that the screen reproduction of colours in RGB colour mode can (and in most cases, especially with Windows computers and budget monitors, does) differ considerably from the actual colours of the objects in a photo, Unless your screen is set to a white point of D65 and precisely calibrated with a colorimeter, certain colour aberrations are virtually inevitable. On top of that, lighting conditions and individual camera settings have noticeable additional impact on how colours are reproduced in a photo.

This means that if you only use a photo to choose the colour for your piece of our Acoustic Cloth, what you get may not be what you’ve seen and expected. Sure we accept returns in most cases and are happy to exchange them for another colour. But it will delay your project, you’ll have to cover the postage if you return an order, have to bring it to the next post office and so on.

Why not avoid all the hassle by ordering a sample set? It will provide you with an absolutely reliable  way to find the right colour for your project if go for anything else than black or white. They are about postcard size, so they also give a good impression of how the fabric appears as a larger surface.

packaging acoustic speaker cloth samplesDon’t get us wrong: The reason behind this blogpost is not to increase the turnover from sample sets. Okay, we charge a couple quid for them, but if you consider the material costs (the production of 100 sample sets requires a whopping 90 square metres of speaker fabric) plus the time-consuming work of putting the sets together, you’ll find that we don’t make any money from samples. We rather subsidise them to offer our customers a reliable and convenient way of finding the right colour.

Beovox CX50 and CX100 upcycled

The great days of the classic passive loudspeaker seem to be over: In times of AirPlay, DLNA, and streaming, WLAN loudspeakers are virtually ubiquitous. On the other hand, however,  true audiophiles and devotees of classic hi-fi technology still prefer sound reproduction at the highest possible level to the convenient, wireless omnipresence of MP3-compressed music. Are these totally incompatible points of view, or is there a way to combine the outstanding acoustic characteristics of venerable passive speakers such as the Beovox CX50 and CX100 with the advantages of sophisticated WLAN technology?

Upcycled Beovox CX50 with Akustikstoff.com speaker fabricThere is indeed, at an amazingly high level. The solution entered the market last year: the Beocreate 4CA. This four-channel amplifier, designed by the Swiss company HiFiBerry together with Bang & Olufsen, updates passive loudspeakers to state-of-the-art active speakers with full wireless functionality in a few simple steps. Even better, this handy DIY solution works with speakers from all manufacturers.

The folks at HiFiBerry refer to the digital upgrade of vintage speakers as “upcycling”, and it doesn’t sound odd: Updating excellent passive hi-fi speakers surely makes much more sense than the »creative« utilisation of (most often new) Euro pallets for trendy but rather uncomfortable garden furniture and the reuse of scrap tire snippets as equally uncomfy shoe soles.

And if you’re already about to upcycle your speakers with the smart Beocreate device, why not attach new cloth to your speakers as well? After all, the speaker fabric used with most B&O speakers is extremely delicate and most probably got a bit long in the dent anyway – just like may be the case with most other vintage speakers. Unfortunately, most manufacturers have been a bit too keen on saving a few quid by using budget speaker fabric. But the HiFiBerry staff have also spent a few thoughts on the visual refurbishment of old speakers: They’ve come up with a blog post in which they describe how to replace the speaker cloth of the popular 80s classics Beovox CX50 and CX100. It’s more or less a matter of course that they also rely on the highest possible quality for the speaker fabric. That’s why they recommend products from Akustikstoff.com: https://www.hifiberry.com/blog/changing-the-spaker-fabric-of-your-beovox -cx-50 cx100

HiFiBerry is no stranger to DIY hi-fi circles around the world: The leading provider of audio add-ons for the Raspberry Pi has a clear focus on high-quality sound. For several years, HiFiBerry has been developing hardware-on-top modules and digital interfaces – some of them with onboard amplifiers that are mounted directly on the Raspberry Pi. HiFiBerry boards can be used to create streaming players and media centres, but also to customise multi-room setups.

How to Tell the Quality of Acoustic Fabric

The range of textiles that are offered as speaker cloth or acoustic fabric is almost impossible to grasp, particularly on the Internet. But what makes a true acoustic cloth? Here’s a short quality checklist:

1. Maximum sound transparency

Sound measurements of acoustic fabric from Akustikstoff.comAcoustic information, i.e. sound waves, must be able to penetrate the material as freely and unchanged as possible. Unsuitable fabrics will impair the sound—especially the high and high-mid frequencies—because sound waves are absorbed or diffused. That’s why simple air permeability is no sufficient criterion for the quality of a speaker fabric or acoustic cloth.

Only lab measurements will reveal what a specific fabric is actually suitable for. A direct comparison of measuring results generated with different types of speaker fabric reveals that even a double-layer of standard Acoustic Cloth from Akustikstoff.com is more sound transparent than other polyester or linen fabrics.

By the way: Strictly speaking, fabrics like molleton, which are meant to absorb sound rather than let it through, are not an acoustic fabric but an insulating material.

2. Sufficient opacity

knitting machine for acoustic fabricA good acoustic fabric bridges the physical gap between sound transparency and opaqueness. It will usually be developed exactly for this purpose and produced on state-of-the-art machines, which make an appropriate material structure possible. After all, the fabric is used as speaker fabric, as cover fabric for acoustic elements such as absorbers, diffusers, and bass traps, for AV furniture and instrument amplifiers such as guitar amps, in the car hi-fi sector, and last but not least for cladding in shop fitting, exhibition stand construction, and interior design. Of course, there are physical limits to opaqueness. You can find some more details on this topic here.

3. Elasticity

protoype equipped with speaker cloth from Akustikstoff.comAcoustic cloth requires some tension to ensure an even surface of the cabinet front. That’s why it needs to offer exactly the right amount of horizontal and vertical elasticity. Any fabric that is too elastic will warp during processing and crinkle or buckle after a while. If it’s too rigid, on the other hand, workability will suffer, which can also cause crinkles. Standard Acoustic Cloth from Akustikstoff.com can even be easily stretched around several edges and finally stapled to the frame, as this photo of a model for the speaker cover of a high-end loudspeaker shows. With the topic of stapling we get straight to the next point:

4. Ruggedness

Extra-robust PA-Type Acoustic Cloth from Akustikstoff.comSpeaker fabric is often stretched around hard edges and stapled (watch this tutorial to see how it works), and high-quality acoustic fabrics are durable enough to stand this procedure without laddering or tearing. The weight of a certain speaker cloth usually is a good hint at its stability: Fabrics that weigh between 90 and 140 grams per square metre consist of a single layer of very thin yarn—which puts them close to nylons. No wonder they are similarly sensitive. Akustikstoff.com offers only robust double jersey with a weight of 180 grams or higher per square metre. The particularly rugged PA-Type Acoustic Cloth, which is equipped with a special protective net on the front, even reaches 550 grams without any loss in sound transparency.

5. Even structure

cheap, uneven, lightweight speaker fabricCloseup of Akustikstoff.com fabric

 

 

 

 

 

 

High-quality acoustic fabric is characterised by its even structure. It’s quite easy to distinguish good material from cheap qualities at first sight in direct comparison. Simply have a look at the image: The crinkled fabric on  the left is an imported fabric from somewhere in East Asia. It is offered at prices of about 8-10 euros per square meter by various stores on the Internet and on Ebay without any information about the origin and the manufacturer of the fabric. On the right there’s a photo of the more expensive proprietary fabric made in Germany by Akustikstoff.com–of course taken from the same angle and from the same distance.

6. Flawless workmanship

Faults in cheap speaker fabricAcoustic cloth is a rather delicate fabric, so only high-quality raw materials and perfect processing in all steps can prevent quality defects. And as always, careful processing and consistent, fastidious quality control have their price.
An example of common quality defects are ugly traces of worn needles. Actually, this should be an absolute no-no for any supplier. Such fabrics are clearly seconds that any professional customer will reject. Unfortunately, such defects are quite common with low-cost no-name speaker fabrics such as the budget cloth in our example. Taking a look at the fabric at backlight conditions clearly shows the sloppy work. If you attach some importance to detail in the realm of your hi-fi and AV equipment, you will most probably not be pleased with such speaker fabric.

Uneven colouring due to the use of non-mixed, uncontaminated yarn is another quality flaw that can often be observed with cheap speaker cloth. It is particularly noticeable with dark colours, when somewhat lighter stripes cause an irregular surface. That’s why acoustic fabrics from Akustikstoff.com are exclusively made from high-quality, white polyester yarns.

7. HSE and social responsibility in production

Yarn for Akustikstoff.comAzo dyes, formaldehyde, heavy metals … There’s quite a number of hazardous chemicals that may be hidden in textiles, and the use of some of them is still not sufficiently regulated by law. Even worse, the main reason for the use of these questionable substances, which are still often found in imported textiles, is to ensure cheapest possible production processes. Questions about potential risks for humans and the environment and about the working conditions under which these fabrics are produced are simply ignored. At first glance, the end product may seem “inexpensive”, but closer inspection often brings a different picture to light.
That’s why all fabrics in the product range made by Akustikstoff.com are certified according to the OekoTex 100 standard. This long-established standard contributes to high and effective product safety. The test criteria and limit values often go well beyond the national and international requirements, extensive product controls and regular company audits ensure compliance with the strict guidelines.

Acoustic Cloth for »Acoustic Pictures«? Indeed!

Over the past few weeks we’ve received an increasing number of questions about so-called acoustic pictures, a certain type of acoustic panels that  seem to be the latest craze among HiFi and home theatre devotees. In most cases the conversation starts like “I want to make a DIY acoustic picture. Can’t I use that lovely piece of cotton cloth I already have? It’s relatively permeable to air, and the actual acoustic work is done by the absorber behind it anyway, right?

The answer to the second question is a straightforward “yes”. Only the absorber itself influences the sound in a room by absorbing sound waves. From a technical point of view, you don’t really need to cover absorbers at all. Unfortunately, an open absorber is a true eyesore. That’s why you better attach a front cover.

Absorber covered with acoustic cloth in a studio

Absorbers for professional studios are always covered with special fabrics that ensure maximum acoustic transparency. The design and construction of acoustic pictures should follow the same principle.

When it comes to selecting the appropriate fabric for this cover, however, maximum sound permeability is the key criterion – for a very simple reason: Only sound waves that reach the absorber can be absorbed. Sounds logic, eh? There’s nothing to be gained from a cover that reflects the sound before it hits the absorber. So our answer to the fist question is equally straightforward: “you better don’t!”

Simple air permeability doesn’t mean much at all. Even a sanforised sheet of mercerised cotton is permeable to air. The key question is the speed at which the air permeates the fabric, or how much resistance it has to overcome. The higher this resistance, the lower the acoustic transparency and the higher the reflection of higher frequencies. Just as you do not want to cover the fronts of speakers with a dense cotton fabric or canvas, you wouldn’t use such fabrics for acoustic pictures that are supposed to do their job properly. After all, there are acoustically effective elements involved in both cases: a loudspeaker, which is a sound wave generator, on the one hand, a sound absorber on the other hand. And there’s a simple rule that applies to all acoustically effective elements: For optimal acoustic results, virtually nothing should be placed between the acoustically effective element and the human ear.

So correct material selection makes quite a bit of a difference. It’s highly advisable to use nothing but high-quality speaker cloth, even if some suppliers of ready-made acoustic pictures staunchly claim the opposite. A handful are really telling porkies when they sell standard stretcher frames covered with printed canvas and filled with absorber material as “effective acoustic panels”. Such constructions are virtually non-transparent to sound. Even worse, they tend to reflect mainly high-mids and high frequencies – which are perceived as particularly annoying, because they make up the essential part of a room’s audible reverb. Okay, the professional audio sector certainly places much higher demands on the acoustic properties of a room than a home user usually does. We can also take for granted that aesthetic considerations in your own four walls are most probably completely different from those that apply in a recording studio or a speaker’s cabin, especially if you’ve decided to build your own acoustic panels. Nevertheless, don’t pour your money down the drain for such iffy stuff.

Our range of Acoustic Cloth has been carefully designed for a maximum of sound permeability plus sufficient opacity. And if you want to design your 100% individual acoustic picture, you’ll be happy to hear that our standard Acoustic Cloth is suitable for printing. All you need is a flatbed printer (which is something every major digital print shop calls its own nowadays). This is the perfect solution for DIY acoustic pictures that combine excellent acoustic property and individual design – all the more so as Akustikstoff.com offers an enormous amount of design options: 42 standard colours plus nine metallic colours.

DIY acoustic pictures

So-called acoustic pictures for home use are very much in vogue. These sound-absorbing elements improve the acoustics of a room by eliminating unwanted sound reflections, and they can look good too.

The good thing is that there’s a quick and inexpensive way of making them as a DIY project: The first step is the construction of a wooden frame with an edge height of about 5 centimetres. Then, a special acoustic foam such as Basotect is tightly inserted in the frame. Finally,  the front of the entire construction is covered with an acoustically transparent fabric, such as Acoustic Cloth.

Akustikstoff.com fabrics are particularly robust and elastic, which ensures easy processing in the DIY workshop. Our Youtube channel provides a number of practical tutorials that apply to loudspeaker frames as well as for acoustic pictures.

akustikbild oder schallbild aus akustikstoffHave a look at the photos one of our customer has kindly provided to give an impression of how good such DIY acoustic pictures with our Acoustic Cloth can look in a room. Thanks to a choice of 42 colours and a further nine metallic shades, there are no limits to creativity here.

Of course, you can give your DIY sound pictures a further individual touch by painting them with suitable textile colors. Just make sure that the colour doesn’t clog the pores of the acoustic fabric.

To fix the textile colours, the polyester speaker fabric can be ironed at up to 175 ° C. Simply put a piece of thin, flat cloth between the Acoustic Cloth and the iron. It makes some sense to mount the fabric on the frame only after fixing the paint. If you do so, make sure that the picture isn’t spoiled by uneven tension. And if this appears to be too tricky,  you can also mount  the fabric on the frame first, then paint it like canvas on a stretcher frame, then fix the colors by ironing from behind, and finally insert the acoustic foam tightly in the frame. Just make sure not to paint the areas of the Acoustic Cloth that are right on top of the frame, as you cannot iron these areas properly afterwards.

Please note that  due to its water-repellent and stain-resistant properties, Acoustic Cloth 2.0 is not suitable for painting.

B&O Beolab 8000 Speakers Looking Like New Again

Beolab8000-with-akustikstoff-acoustic-clothThe Beolab 8000 from Bang&Olufsen an iconic example of elegant styling and good performance . It was one of the most successful B&O loudspeakers ever, remaining in the range for 18 years without any major change. Many music and home theatre lovers still hold the Beolab 8000 in the highest regard and consider it a purchase for life—no wonder in view of the whopping £2940 you had to cough up per piece in 2010 , which was the last year of production.

 

But as the saying goes, nothing is perfect. In the case of the Beolab 8000, the delicate speaker grill cloth was a definite downside. It didn’t take long and the speaker fabric looked much older than it actually was, which compromised the design (and reduced the value) of the speakers considerably.

 

refurbishment-of-beolab8000-with-akustikstoff-acoustic-fabricLuckily, it is quite easy and inexpensive to return the speaker front to its former glory. Our standard acoustic cloth does a perfect job on the Beolab 8000. Even better, the readily available 42 colours of Akustikstoff.com speaker fabric provide the opportunity to achieve a totally new, individual visual appearance and adapt them to your personal taste in a very unique way.

 

 

 

Beolab8000-with-akustikstoff-acoustic-cloth   Beolab8000-with-akustikstoff-acoustic-cloth

Speaker refurbishment of B&O Beolab 8000 with black Akustikstoff.com acoustic speaker cloth.

Opacity of Speaker Fabric – Technical Basics and Best Practice

You can’t eat the cake and have it:
Why an acoustically transparent fabric can’t be 100 percent opaque

“Is your Acoustic Cloth really opaque?” That’s a question our customers ask quite frequently. After all,  speaker fabric from Akustikstoff.com is primarily used to hide loudspeakers, AV equipment or whatever else as elegantly as possible without impairing acoustic transparency.

Strong contrast leads to marking with any acoustically transparent fabric.

Marking with acoustically transparent fabric: a deep black background remains somewhat visible under white speaker fabric.

The theoretical ideal is obvious, of course: absolute acoustic transparency plus absolute opacity (i.e., the opposite of transparency) at the same time. Unfortunately, the laws of physics counteract this ideal, since both sound and light are waves – temporal and local periodical changes of a physical quantity in the dry language of physics.

 

It’s all about waves

As sound propagates through the mechanical deformation of a medium, in our case by changes in air pressure, everything that is in the way acts like a kind of barrier: It is moved itself and starts vibrating, this way absorbing energy from the impinging waves, and it reduces the amplitude, i.e., the magnitude of the oscillation. That’s why a completely closed, airtight surface always attenuates sound waves. Depending on the material, the sound is “swallowed” by resonance and usually reflected or diffused to a certain degree at the same time.

Put the other way round, high acoustic transparency is simply impossible without openings, through which air – and thus the sound – can penetrate. Even the smallest apertures, however, can also be penetrated by visible light, which has a much shorter-wavelength. This effect can be experienced in a striking manner in a completely darkened room as soon as the door does not close completely on all four sides of the door frame.

 

Crucial: the higher frequency range

Insufficient acoustic transparency is most noticeable in the higher frequencies within the normal range of human perception: the short-wave, low-energy high frequencies and high mids are attenuated first, while energetic, relatively long-wave bass frequencies are noticeably less hindered. In practice, this means that unsuitable or inferior cloth for acoustically active elements usually eliminates exactly those acoustic frequencies that are of utmost importance for a sophisticated, well differentiated sonic image.

 

Exploring the limits of physics

The secret of high-quality Acoustic Cloth is that it lets sound waves pass through virtually unimpeded but blocks the light waves as much as possible. At Akustikstoff.com, we’ve performed a lot of research and development work to get this physical balancing act done in the best possible way. Nevertheless, it is in the nature of things that both objectives can’t be achieved to the full at the same time. In addition, there’s a third, no less important aspect to be considered in the development of loudspeaker cloth, and we’ve put quite some effort in it: robustness. That’s why all covering fabrics from Akustikstoff.com are remarkably durable and are very easy to process while they feature the highest possible opacity and excellent sound transparency. We’ll go a bit more into details on this in a separate article in the near future.

 

The opacity of dark speaker fabric is higher than that of brightly-coloured speaker cloth.

In pure incident light, dark colours tend to be more opaque than bright colours. Here in comparison: black and white.

Three typical problems with acoustically transparent fabrics

Typically, problems with the opacity of acoustically transparent covering fabrics occur when there’s a strong contrast between a speaker cloth in a light colour and rather dark objects behind it, when there’s light from behind, and when a source of strong incident light is pointed directly at the surface of the Acoustic Cloth.

 

Decrease contrast, increase distance

The most important measure to prevent translucency is to keep the contrast between the covering fabric and the objects behind it as low as possible. It is worthwhile, for instance, to varnish the cover frames and fronts of speaker cabinets and sound absorbers, in matt white if they are to be covered with white acoustics.

In addition, a larger distance between the background and the Acoustic Cloth helps prevent translucency. If, however, the speakers installed in a white housing have pitch black diaphragms, these will nevertheless remain visible under most lighting conditions. In some cases, this may even be desired since the effect can also be very elegant depending on taste and design. A similar transparency effect may occur with absorbers: If grey absorber material (think Basotect®) is covered with a piece of white Acoustic Cloth, the surface will often not appear in pure white, but rather in light grey.

Contrast of black and white with speaker cloth

The two pieces of speaker fabric illustrate the intensive contrast of black and white. However, the contrast between black and yellow is even stronger.

Contrast of black and yellow with Acoustic Cloth from Akustikstoff.com

The strongest contrast: black and yellow – in this case illustrated with two pieces of Acoustic Cloth from Akustikstoff.com

By the way, the contrast between black and yellow is even stronger – hence the colour combination of yellow and black for safety markings.

 

Avoid translucency from behind

A certain degree of optical transparency remains unavoidable if acoustically transparent fabric is exposed to backlight: Similar as with a curtain, the contours – or even more – of objects placed behind a piece of Acoustic Cloth will become recognizable if light is permeating the fabric directly from behind. This problem occurs mainly with AV furniture such as soundboards, soundbars, and lowboards. To avoid this “curtain effect”, place your AV furniture cleverly to prevent daylight from shining through and don’t put any artificial light sources behind the furniture.

 

Strong incident light leads to transparency

Strong, bundled light that is directed right at the front on the speaker fabric can also lead to transparency effects: The light penetrates the Acoustic Cloth, is reflected by the objects behind the cloth in the opposite direction, permeates the fabric again and this way leads to a certain degree of transparency. Such effects can be prevented by not pointing any light source directly at the fabric, rather using diffuse light, and ensuring a lateral light incident.

 

Heavy stretching makes speaker cloth increasingly less opaque.

The “curtain effect”: The higher the tension under which the elastic speaker fabric was mounted, the more transparent the speaker cloth becomes. The photo shows a piece of heavily stretched Acoustic Cloth with bright sunlight from behind.

Mind the tension                

The tension that is applied when processing our acoustic fabric is has a considerable influence on its optical transparency: The more intense the elastic fabric is stretched, the wider the meshes become. While heavily stretching a meshed fabric may improve its acoustical transparency (you won’t really need to do this with Akustikstoff.com Acoustic Cloth, as the utmost sound transparency was our primary design objective), it also changes the opacity of the material. This can lead to the so-called “curtain effect”: especially in the case of backlight, the fabric becomes progressively less opaque with growing tension. In such a case, it is necessary to experiment somewhat before final assembly.

 

Use two layers?

Depending on the application, it may be possible to use two layers of Acoustic Cloth to improve the opacity of the speaker fabric. The acoustic losses, an additional reduction by approx. 1-2 dB at approx. 8-9 kHz, are well within the acceptable range. Even if you use two layers of our Acoustic Cloth, acoustic transparency remains distinctly higher than that of other single-layer materials*. However, it is necessary to work very carefully in order to avoid the dreaded moiré patterns that the fine structures of the fabric may cause when they’re spatially overlapped. To a certain extent, this can be avoided by using the more structured surface of the fabric as the outer side at the front and the second layer with the slightly smoother side outwards. Then twist the two layers of fabric against each other until the moiré effect disappears. Again, some experimenting prior to the final fixation of the speaker fabric will ensure an optimal result.

*Schmid, Johannes: “Messungen zur akustischen Durchlässigkeit verschiedener Textilien“. Jade Hochschule University, Oldenburg, Germany, September 2015

How to Order Speaker Fabrics by the Metre

Sometimes people have some difficulty in ordering our acoustic cloth by the metre. Here’s a concise tutorial that helps you through the ordering process. It applies to all types of acoustically transparent fabrics from Akustikstoff.com.

1. Enter amount
simply indicate full metres of speaker fabricOnce you’ve decided which speaker cloth to take (Speaker Cloth off the Roll, Acoustic Cloth 2.0, PA-Type Speaker Cloth, or Metal Line Speaker Cloth), simply enter the full metres you require in the box we’ve highlighted with a red circle in the screenshot. Please make sure to enter integral numbers only, as all fabrics are only sold by the full metre.

2. Choose Colour

choose colour of speaker fabricIndicate the colour you desire by clicking the appropriate radio button next to the colour image (see red circles in the screenshot).  Then click “Add to shopping cart”. All possible discounts will be calculated automatically and are indicated in the shopping cart overview (see step 3).

 

 

3. Check Details

easy shopping cart overview on akustikstoff.comOnce you’ve clicked the “Add to shopping cart” button, you’ll be directed to the shopping cart overview: Amount in metres (red circle), single (discounted) price (blue circle), and total discounted price (green circle). Please cross-check all details before checking out.

4. More Cuts, More Colours, Other Stuff?
No big thing! Simply perform steps 1. to 3. for each piece of fabric and each colour you require. The shopping cart will always provide you with the full overview.

5. Make sure to Optimally Benefit from Tiered Pricing
Keep in mind that our tiered pricing is cumulative. Discounts always apply to the total quantity ordered. If you order five metres of speaker fabric in one colour and another six metres in a different colour and/or different quality with a single order, the price tier for 10m-15m will be applied.

 

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