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Tubetraps; Speakerstands; Room Acoustics

Tubetraps have some excellent articles on their site, including 'The Wall in the Desert', which explains how a room changes the sound from your loudspeakers.Tubetraps have some excellent articles on their site, including 'The Wall in the Desert', which explains how a room changes the sound from your loudspeakers.

Martin Walker is the first to take the chair in our new regular column on Internet‑based resources for the hi‑tech musician. This month, he looks at sites that aim to help you improve the sound of your studio.

Surfing the Net can be a wonderful or frustrating experience, depending entirely on what you find. When you are looking for information on a particular subject, search engines can throw up hundreds or even thousands of possibilities, but despite (or because of) this, you can still often fail to find what you are looking for. Net Notes is a new column that aims to home in on subjects of particular interest to musicians, and it will be chaired by a variety of SOS contributors. Although there will be quite a few URLs on offer, you should also be able to find this column on the SOS web site (www.soundonsound.com/), so you can point your browser there to click on links directly. The beauty of this dual‑pronged approach is that you can still browse through this information at your leisure, from the comfort of an armchair, which will keep your phone bill down when you're actually on line.

My chosen subject is one that affects us all: getting the best sound in your studio, whether it is a commercial venture, or crammed into a spare bedroom. Series on improving acoustics are always a popular subject in SOS (see the fifth part of Paul White's series starting on page 206), and there is a huge variety of sites which can provide further useful information; much of the material mentioned here is best downloaded to your hard drive to be read at your leisure. If you are comparatively new to the subject, you will find the content of some sites easier to understand than others — they vary greatly in the amount of technical content, but there should be something for everybody here.

Room With A View

The RPG Diffusor site has a downloadable demo of its Room Optimiser software, which calculates the optimum position for both you and your loudspeakers.The RPG Diffusor site has a downloadable demo of its Room Optimiser software, which calculates the optimum position for both you and your loudspeakers.

A good starting point is understanding why a room can affect the sound coming from our monitor speakers in such a radical way. A rather fetching description of this can be found on the Tubetrap site(www.tubetrap.com). Expect a review of this company's Studio Traps soon; apart from a lot of useful information on their own products, their web site also contains more general articles that put them into perspective. 'The Wall in the Desert' (www.tubetrap.com/articles/witd.htm) is an article originally given as an invited lecture at an audio show in Italy, and explains why your studio or listening room is the final link in the audio chain, and why it is just as important to the final sound we hear as the amplifier or speakers. Another more advanced article is 'The Chain is as Strong as Its Weakest Link' (www.tubetrap.com/articles/chain.htm), which takes things further, including an overview on dimensions and floorplans, basic construction, equipment (including suitable lighting design), and control of reflections.

For a more down‑to‑earth DIY approach to small studio acoustics, BKL Consultants of Vancouver (www.bkla.com) have some useful sections on their site. There is a Home and Project Studio FAQ (www.bkla.com/stdiofaq.htm), and the section on common acoustical problems includes a series of downloadable WAV and AU files which illustrate excess reverberation time, late reflections, and inadequate loudspeaker coverage (www.bkla.com/problems.htm). If you are keen on DIY, then the Recording Studio Design Page (www.mcs.net/~malcolm) has a lot of text‑based information, as well as an interesting pair of plan and elevation diagrams for a 'Live End, Dead End' control room design. It is a non‑commercial site, and the information has been amassed over 40 years of studio recording and design experience.

A Guest Speaker

Once you realise the importance of the room, it's hardly surprising that accurately positioning your speakers within it is also vital. Chesky Records are well known for their audiophile quality recordings of world, classical and jazz music, and while browsing their site I came across a useful book extract on 'How to Get the Best Sound From Your Room' (www.chesky.com/omaha/chesky/libr...).

This covers all the basics, but if you enjoy the more esoteric approach of ultimate hi‑fi, you'll love the Cardas site (www.cardas.com) which, apart from the extensive design philosophy of its high‑end audio cables, also has a section devoted to speaker positioning in relation to the room. George Cardas claims that very precise speaker placement can open up a whole new dimension in listening, and provides precise details on how to achieve this with any reasonably sized rectangular room. You can find this at 209.3.64.161/insights/roomsetup.html. If you are building a room from scratch, you will also be interested to read details of the Golden Cuboid room, whose dimensions progress in the Golden Ratio or Fibonacci sequence (5, 8, 13, 21, 34), which should give you the 'perfect listening room'. Apparently, the AES standard listening room is a Golden Cuboid measuring 10 feet by 16 feet by 26 feet.

RPG Diffusor Systems are well known in acoustic circles, and their products have been used in many commercial studios, one of the most famous being Peter Gabriel's Real World. Their site at www.rpginc.com not only contains details of their many products, but a free demo version of their Room Optimiser software (the demo is fixed to room dimensions of 20 feet by 10 feet by 10 feet). This will run with Windows 95 (but not Windows 98, it seems), and will automatically determine the best (and worst) positions for the listeners and loudspeakers (up to 20 if needed), the optimum height for the speaker stands, as well as indicating the position and type (absorbent, diffusing, or combined) of any acoustic treatment needed.

As you might expect, speaker manufacturers can also be a useful source of speaker positioning information. The Hales Design Group, based in California, manufacture hi‑end loudspeakers, and have on their site the 'HDG University' — a useful source of more information about speaker setup, stereophonic considerations, and listening room considerations (including detailed explanations of standing waves, and graphics explaining the difference between reflection, absorption, and diffusion). The site can get a bit technical, but is still comparatively easy reading in most areas. Take a peek at www.halesdesigngroup.com/hdgu.html

Another related subject that causes problems is the positioning of subwoofers, which can often be tricky to balance with the rest of your system. Swedish company Sonic Design have a useful article on this subject at www.sonicdesign.se/subplace.html

Stand And Deliver

Speaker stands can do a lot more than place your nearfield monitors at a suitable height. For a discussion of just what makes a good stand, take a look at www.feist.com/~nihil/stands.html. This is just as applicable for the recording studio as the hi‑fi listening room, and site owner Jonathan Atkins also mentions oft‑forgotten points, such as the fact that some speakers sound better when their tweeters are slightly above or below ear level, and some stands need filling with sand (or cat litter) to stop them resonating.Things get a little less cut and dried when you actually install the stands. They are often provided with adjustable height spikes instead of feet, which are designed to give them maximum stability on uneven floors. With a floating floor, the spikes can also have an audible effect due to bass frequencies travelling down the stand and directly into the floor. However, spike 'enthusiasts' claim benefits from coupling the speakers and stands more closely to the floor, so that unwanted cabinet and stand resonances are 'drained away'. The merits (or otherwise) of this are shrouded in pseudo‑science, and an argument against the use of floor spikes can be found at www.feist.com/~nihil/spikes.html — author Doug Purl doesn't leave you in any doubt as to his views.As soon as you place your nearfield monitors on top of the stands, another hotly disputed subject is what should be placed between the two. There is a wide variety of suggested options, ranging from neoprene blocks and Blu‑tack right through to a range of fairly sharply pointed cones made of wood, metal or ceramics. Many people who have tried these tweaks have heard subtle but audible differences, but there are again widely conflicting views for the different options.One persuasive argument can be found on the site belonging to Sonic Design (www.sonicdesign.se/sdfeet.html), whose damping feet are claimed to absorb loudspeaker cabinet vibrations before they enter the stand, as well as stopping these vibrations from generating floor movement at the other end. The accompanying oscilloscope traces do suggest that using hard cones as well as spikes can cause speakers to generate harmonically related floor movements, but it is still difficult to judge how much (or how little) an effect these will have on the overall sound from the speakers.

Acoustics In Recording

Once you have a greater understanding of acoustics, you can also use it to improve the depth and dimension of your recordings, by using various mic techniques. For the beginner new to mic techniques, a section entitled 'Sound Balancing' can be found at Doug Barnes' Music Technology Handouts (www.users.globalnet.co.uk/~bunce...). In addition to the basics on mic positioning, there is also a wealth of other information on a wide variety of other music‑related subjects, including the basics of sound, MIDI (including timecode and controllers), mixing, and record production. These notes on music technology were originally written as handouts for students on examination courses at a further education college in England, and are very easy to read.

For the more advanced recordist, a wonderful source of wisdom can be found at the Digital Domain site (www.digido.com), which is hosted by well‑known recording and mastering engineer Bob Katz. Amongst a variety of highly informative articles which cover CD mastering, compression, jitter, and dither, he has also penned one entitled 'How to Achieve Depth and Dimension in Recording, Mixing and Mastering' (www.digido.com/depthessay.html), which covers masking, the Haas effect, and then goes on to describe various recording techniques suitable when recording acoustic instruments, to achieve front‑to‑back depth. I am sure that even experienced engineers could learn something from this excellent site.

Cheap Tweaks

If you are intrigued by some of the system tweaks suggested in hi‑fi magazines, but can't manage some of the 'exclusive' prices, take a look at the Cheap Tweaks page of the American Hi‑Fi magazine (www.hi‑fi.com/diy/tweaks/). This contains some fun tweaks to try out for a pittance, and although they mainly use items from a large US‑based catalogue company, I'm sure you could find similar items in the UK. It is the lateral thinking that appeals to me. For instance, if you want more acoustic isolation, why not try supporting your hi‑fi equipment on an inflatable ring originally designed for haemorrhoid sufferers? Another good set of basic tips can be found at www.dreamscape.com/afasoldt/text... — which provides '10 ways to improve your audio without spending money'.

Finally, if you think that tweaks are for people with too much time on their hands, you'll identify with 'Why rant when you can rave?', found at www.communities.com/people/gordi.... There's even a 'Fun with Audiophiles' section, with a selection of ways to wind hi‑fi enthusiasts up in a big way.

Overall, you can learn a lot from visiting the sites mentioned here, but my 'Site of the Month' award must go to Bob Katz and Digital Domain. Whenever I return to it and find a new article it is immediately downloaded and stored on my hard drive for further study.