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Email: sales@cmacoustics.co.uk

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Email: info@cmacoustics.co.uk

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1A, Sileby Road Industrial Estate, 233 Sileby Rd, Barrow upon Soar, Loughborough LE12 8LP
Company Registration 08655270 - VAT Registration 213042174
©copyright CM Acoustics Limited 2014

How quickly will my order be shipped?
 

For orders that require upholstering in your chosen colour (i.e fabric faced panels), we generally advise 7-10 days before they are placed on a 24hr delivery service, but we do aim to get them out sooner than this.

For custom sizes lead times will vary but we will advise you of this at the point of enquiry.  

 
 

My order is urgent, can i get it next day?


Some of our products are available for next day delivery through stockists and resellers of our products. Contact us to find out your nearest stockist. 

Can i collect my order?


Yes. Just advise us that wish to do this and we will contact you when your items are ready. 

 
 

Can i arrange my own shipping?


Yes. we can work with your own carriers to co-ordinate the delivery of goods. This has proven successful for those ordering from the rest of the world and who regularly ship goods from the UK. 

 

Do you do discounts for large orders?


Yes. Contact us to discuss further as larger orders generally qualify for a discount. 

How are large orders delivered?


Sometimes large orders may be better shipped by pallet delivery, but we will advise of the most cost effective shipping method for you. Palletised deliveries generally will arrive on a curtain sided lorry for offloading by the customer, either by hand or by forklift. Most customers have no trouble hand-balling items off of the lorry, but do advise us if this will be an issue before ordering. 

 
 

Can i mix panel colours?


Yes. it makes no difference on cost. The only difference in cost will be if looking to have different fabric types. All items quoted for are from the Cara range of Acoustic Fabrics, any Lucia fabrics required are slightly higher in price, contact us for a quote if required.  

Do you do custom shapes and sizes?


Yes. We have a full joinery workshop as well as CNC machining methods at our disposal. Large or small, weird or wonderful, contact us to discuss any designs, shapes and sizes you would like.

 

How do i hang your panels on to my wall?


For installation information click here

 

How do i hang your panels on to my ceiling?


For installation information click here

 
 

Acoustics Knowledge

What is Speaker Boundary Interference Response (or SBIR)?

 

SBIR is the term used to describe sound reflecting off a boundary (or wall) combining with the sound source (speaker or monitor). When this occours, there will be notable dips in lower frequency response.

 

Why does this happen? This happens because lower frequencies radiate from the sound source spherically (or in an omnidirectional fashion) coming from front, back as well as all other sides, whereas mid and upper frequencies are mostly unidirectional. If lower frequencies are reflected off a nearby boundary they will combine with frequencies coming from the sound source.

The ¼ wavelength rule tells us that direct sound and reflected sound combining will be 180 degrees out of phase, This causes interference and cancellation. Which will mean null's in bass response.

 

 

How do we deal with SBIR? Speaker Placement and Acoustic Treatment.

With speaker placement there are a couple of things you can do to deal with SBIR.

 

Place speakers as close as possible or as far away as possible to the boundary. What does this do?

 

The further away from the wall your speakers are the lower the frequency will be that causes cancellation. The goal here is to move the speaker beyond the range that your speakers can produce. However this is not always practical as the majority of users have limitations on space.

 

Moving your speakers closer to the wall will shift the frequency that causes cancellation further up the frequency spectrum. This is the most common method of managing SBIR, because the frequency is then moved into a more manageable range, and when we say manageable, we mean treatable.

 

So how do we treat the offending frequency? We use Acoustic Panels, or more specifically bass traps or Broadband absorbers. This lowers the amplitude of the reflected frequency. We would recommend using the CM486 Broadband Absorber behind the sound source however where the frequency to be treated is lower, a thicker panel may be required, in which case you may want to look at using our CM886XL Bass trap.

 

Remember that SBIR can occour from the side boundary in addition to the boundary behind the speaker.

 

 

What are early reflection points and how do I treat them?

 

In a monitoring environment or home cinema environment there will be a certain level of reverberation. Some of this reverberation will be a result of sound bouncing off of a nearby boundary or wall. It is important to control the level of these early reflections so that you can hear your speakers more accurately. Failure to treat these reflection points will result in direct and reflected sound to combine causing frequency build up and cancellation. In a monitoring environment where sound is mixed it is important to minimize these reflections as you will need to be able to judge what your listeners will be hearing when your produced sound is played back in other environments.

Early reflections usually arrive from side walls and ceilings when the listener is located centrally in the listening position. Absorbing these reflections will give you a more accurate response from your speakers and provide better stereo imaging at the listening position.

 

Acoustic Panels or broadband absorption panels can be used on these early reflection points.

 

To locate the early reflection points on side walls, the widely used mirror trick can be employed.

 

While seated in the listening position, have somebody hold a small mirror against one of the side walls at the hight of the tweeter in your speaker. Have them slide the mirror along the wall starting parallel to the speaker going towards the listening position. When you see a speaker in the mirror, mark the wall, this is where you place acoustic treatment, our CM486 Broadband Absorbers are perfect for this. Continue and you should see the next speaker (so thats both left and right speaker speakers reflection points marked) Repeat on the opposing wall. Once you have these areas marked out, it is safe to assume that any ceiling treatment for Early Reflection points will be parallel to the first reflection points marked out. Again our CM486 or CM286 or CM24CL cloud will work for ceiling treatment of the early reflection points.

Treatment of early reflection points will help with stereo imaging, it will also go some way in ensuring that you have a reflection free zone within your room (RFZ) however due to limitations of space and walls not being identical either side (i.e. you may have a window on one side), then a stand mounted absorber may be used. See our CM486G for information on stand mounted absorbers.  

 

What do you recommend for treating the rear wall in my room? 

In any studio space or listening space (home hifi or cinema) generally we would recommend bass trapping and/or diffusion. Usually a combination of the two works best as diffusion will evenly scatter the mid and upper frequencies whilst bass trapping will absorb the lower frequencies, this method of rear wall treatment will ensure that the acoustic treatment that you install is not over deadening the space by completely absorbing all the sound energy. Diffusion will also open up the sound field and give a sense of space whilst eliminating frequency build up.

 

Lower Frequencies will build up behind the listening position, this will affect the response within the centre of the room also. By treating the rear wall you are eliminating this build up and addressing the room mode, and consequently moving towards a flatter response within your room. All of our acoustic panels feature an airgap, however if you can increase this airgap by mounting our CM886XL Bass Traps or CM486 Broadband absorbers offset from the wall even by 50mm, then you will be increasing the lower frequency absorption performance of these panels.
 

 

Why and how do i treat my room corners? 


We treat room corners with absorption because lower frequencies will build up in these areas. This is where the most pressure is and it can also be a great starting point for anyone under taking room treatment.

A lot of people will see studios with full floor to ceiling absorption within the corners. This is the best route and our CM486 Panels can be used across room corners and stacked if required. However if it is not feasable for you to treat from floor to ceiling then a single panel such as the CM886XL or the CM486 will suffice.


 

If it is feasible then chunkier absorbers will be even better as you are adding mass. (as pictured above at an installation CM Acoustics did for the studios of Salford City College in Manchester).

What is acoustic diffusion?

 

Diffusion unlike absorption, scatters sound back into the room except unlike a bare surface, where the sound remains as it was prior to meeting the boundary surface, a diffuser will break the sound up in a calculated and even manner. It will eliminate comb filtering, standing waves and flutter echos. As opposed to deadening the space, a diffuser will help maintain the sound energy within the room, thus widening the sound field.

The reason why real diffusers like the CMN74 are used as opposed to random objects (like a shelf full of books), is because they are designed to scatter the sound evenly in both direction and time. If a diffuser is simply random and not designed correctly it can cause more issues than it solves I.e peaks and nulls. Specially located fins and wells in a well designed diffuser will ensure that the diffused sound goes back into the room without it returning as echo. This is why many who have listened to sound within rooms treated with diffusion will say that the room sounded large.

 

This is not to say that diffusion is going to be the answer to good room acoustics. There still needs to be a reasonable reduction in decay time if acoustically treating a room, and this can only be done by using absorption alongside diffusion.

Acoustic diffusers can be a challenge to build to get a precise and airtight finish, however there many manufacturers offering fully built acoustic diffusers but these can be expensive. As a good middle ground, CM Acoustics offer a flat packed version (as well as fully built), which is machined via CNC for precision and is fully rebated so it can be assembled without the need for powertools (or skill) as each component clicks into place. Further information can be found here.