I'm going to make some sound traps for my studio...

studiorat

PaulBrewer wrote: »

Munro say -
l (I think a lot of DIY studios use roofing felt).

And the BBC, they're the guys who figured out the roofing felt thing after all. (F.Alton)

I posted last night giving the equations for the tuned membrane gig. The post got lost for some reason it seems...

Frequency= 600 X Sqr.root (m.d) if I remember correctly.
M is membrane mass
D is cavity depth.

The equation is somewhat simplified and doesn't take volume into account, but by adding a porous absorber actually inside the cavity you can widen the bandwidth and make improve the absorbition coefficient of the unit.

There was a paper given at AES last year by John Storyk of Walters Storyk that concluded that none of the commercial, "tuned" absorption devices they tested were really worth a sh1te.

Now I'd like to throw a spanner in the whole works and make another recommendation, passive loudspeaker membranes can be more effective than convertional membrane systems since loudspeakers are really good at vibrating over a wide range of bandwidths, and they're damped easily. If it's cost effective to cover a wall with them is another question.

Bagend actually make an active absorber basically using loudspeaker that can be tuned as the room requires. http://www.bagend.com/bagend/ETrap.htm I reckon this is the future...

PaulBrewer

studiorat wrote: »

There was a paper given at AES last year by John Storyk of Walters Storyk that concluded that none of the commercial, "tuned" absorption devices they tested were really worth a sh1te.

.

Are there such things? Do you have examples?

Wasn't it Storyk who designed the original Windmill?

madtheory

Cool, roofing felt is as easy to acquire as plywood

PaulBrewer wrote: »

Seemed to me I was asking a question that didn't suit ...:rolleyes:

In fairness, he has answered that question several times, in detail. A search will show that.

studiorat

PaulBrewer wrote: »

Are there such things? Do you have examples?

Wasn't it Storyk who designed the original Windmill?

They weren't allowed actually mention the manufacturers, and were only allowed use examples A, B, C etc. Mainly because some of the companies attending the convention were supplying these products.

WSDG have been going 40 years, Electric Lady in New York was Storyk's first design job. Windmill was a Munro job afaik.

PaulBrewer

studiorat wrote: »

They weren't allowed actually mention the manufacturers, and were only allowed use examples A, B, C etc. Mainly because some of the companies attending the convention were supplying these products.

WSDG have been going 40 years, they did do Electric Lady in New York. Windmill was a Munro job.

I didn't know that.

I think you'll find the original Windmill was Storyk.

I just got a reply from Philip Newell regarding my pontification.

By coincidence he's just written an article for Resolution magazine on exactly the same subject Acoustics in Small Rooms.

He too agrees with Munro's points which was a surprise to me as they have what I would have thought were polar opposite approaches.

As he says -

' The latter part is pretty much in agreement with what you wrote.'

I've asked for his permission to post here but I'd expect that won't be a runner 'til after publication.

PaulBrewer

madtheory wrote: »

Cool, roofing felt is as easy to acquire as plywood

In fairness, he has answered that question several times, in detail. A search will show that.

A polite referral to those posts by him or others would have been graciously received.

However whilst he did reply to some of my posts my questions remained unanswered.

PaulBrewer

Philip Neweill has just given me permission to reproduce his article. This is a draft version of what may or may not be in next month's Resolution Magazine.

Improving the Working Acoustics in Small Rooms

For a long time now, there has been a growing tendency for sound to be recorded, edited, and even mixed in rooms which have had very little attention paid to their acoustics. All sorts of absurdities are now common, with computers being placed in control rooms, and giving rise to background noise levels of over 50 dBA at the listening position. Combine this with the siting of the rooms in complexes of other, similarly untreated rooms, and where levels of over 80 dBA would be likely to begin interfering with the work of the neighbours, and one can forget about the possibility of monitoring any reasonably high dynamic range programme.
The lack of room treatment also usually goes hand in hand with an uneven low frequency response, and these can sometimes vary very widely, not only within a room, but also from room to room. Excessive reflexion from the untreated surfaces can also spoil the stereo imaging and introduce undesirable colouration of the sound. Inappropriately placed equipment can also go a long way to undermining the monitoring reliability. When such rooms are also used for recording voices, the impacts from the foot-falls of people walking on the floor above can also be a source of ruined takes and lost time. These problems are often exacerbated by insufficient height in the rooms to allow for any remedial treatment.
Economic forces and marketing attitudes have put a lot of pressure on studios to rely on computers for a great deal of their processes. The real cost of the recording/editing/mixing equipment has fallen sharply during the last few years, even though the capabilities of the systems has risen. People have become accustommed to falling prices, but the cost of making good rooms, with good acoustics, has probably risen over the same period of time.
The considerable change in the relative cost proportions of the equipment and the acoustic works has encouraged the financial wizards to decide to either minimise the acoustic treatment, or to allow the sound quality to fall and to do nothing at all to the acoustics. As the competition down the road were also probably cutting costs, the quality losses were not seen to be financially important. Concurrently with this, the marketing departments of the equipment manufacturers have been working at full steam to convince people that the new equipment could effectively dispense with most of the need for good acoustics.
To complicate matters further, as people have pushed to impress their ever-less-knowledgeable clients, it has been unfortunate that acoustic work, when finished, has often neither been visible nor touchable, so its ability to astound the clients has been seen as almost zero. It would be much more impressive, in most cases, to confront the clients with something a bit more fashionable, like a new microphone, a new editing program, or a new pre-amp. Also, an increasing number of clients are now people who have had no experience in top flight studios, and they are so inexperienced about recording acoustics that they are often uncomfortable in rooms which have what were traditionally considered to be good acoustics, especially when the rooms, in conjunction with good monitor systems, revealed the awful truth about the real quality of the clients' recordings. Ignorance can be bliss! ....'But it sounded great on my mobile telephone!'
There are many pressures, nowadays, not to do any better than necessary. In other words, if it will cost more to do it better, but only a very few people will hear the benefit, then to go for better results can be merely seen as a waste of money. Nevertheless, there are many recording personnel who work in truly miserable conditions, and who would dearly love to be able to have better acoustics in their rooms. They realise that when the monitoring is coloured by poor control room acoustics, it can be hard to know if there is a clean sound entering the microphones. They also realise that the good sound of an excellent microphone can rarely, if ever, overcome the colouration from a poor room in which it may be placed.
So, what can be done in a moderate manner to help these poor souls who really are looking to do the best that they can, even if they realise that the results will not be quite like those from a truly world class facility? In fact, there are numerous ways to ameliorate the worst of the problems, but the solutions are not always obvious, and there are rarely any truly cheap fixes.
As an example, and as mentioned earlier, the intrusion of the impact of foot-falls from the floor above is a very common problem. Undoubtedly the best solution to this is to offer to pay the neighbours to fit an impact absorbing floor. Where the ceiling height is low, and a heavy false ceiling is out of the question, this may, in reality, be the only viable solution. Anyhow, once the impact noises are in the structure of the building, isolating the ceiling, from below, may only result in the noises then appearing from the walls. They only seemed to be coming from the ceiling because it was the loudest source. That is, the structural borne noise tends to radiate from all surfaces, so, short of isolating the entire room, it can be much more economical to stop the noise from entering the structure. Nevertheless, all this depends on the good will of the neighbours to allow the work to be carried out in their premises, unless the owners of the studio are also the owners of the floor above, of course.
The newer building regulation in many countries are now beginning to address this problem, but many studios are typically in older and cheaper buildings where not very much thought has been given to impact noises. In so many cases, cost and location are the prime factors in choosing buildings, and acoustic considerations are often given little importance until the contracts on the buildings have already been signed. All too often, the buildings that they choose are too small and too structurally weak to permit much acoustic work. From then on, the whole process tends to revolve around lessening the extent of the problems, rather than the creation of the desired conditions.
In relation to the internal acoustics, one useful element which can help almost any small room is a full-range absorber covering either the wall opposite the loudspeakers, in the case of a control/editing room, or the wall towards which a voice-recording microphone will face; that is, behind the actor or singer. Inevitably, these things do take up space, typically at least 60 cm of depth over the whole surface of the wall in question, but they do go a long way towards very effectively flattening a room. The general concept is shown in Figure 1. Once installed, these 'traps' tend to be like a breath of fresh air for the people using the rooms.
Some people eschew the use of so much absorption, and prefer diffusion, but in my experience, in small-to-very-small rooms, diffusers tend to change the colouration, rather than remove it. They still return the energy to the room, and it comes back very quickly in small rooms, merging with the direct sound from which it then cannot be separated. What is more, even diffusers usually need to be of the same degree of depth if they are to function down to the same low frequency limits. This is a big problem with small rooms, there is little space in which to do anything to control them, Unfortunately, the control measures depend on frequency and wavelength, and not on the size of the room that they are controlling!
Self-measuring, self-aligning monitor loudspeakers have also now become quite a popular way of flattening-out the worst of the response problems in small rooms. Nevertheless, there are a few points which must be considered about the nature of their operation before choosing them as a primary solution to a room acoustics problem. In the first instance, they may improve quite drastically the sound in a small region of a room, but they may also worsen the sound elsewhere. In the second instance, where they have D to A converters after the processing, the converters are unlikely to be of the highest standard. If we take the case of an editing/mixing room for television, and if the room is for a single operator and the downstream reproduction quality of the domestic chain is not likely to be of audiophile quality, then the use of such loudspeakers can be a good option for use in a relatively poor room. On the other hand, if we are considering mixing music for a CD, which can be expected to be heard on some excellent hi-fi systems, then the studio recording converters and the domestic reproduction converters will probably in many cases be way superior to the D to As in the loudspeakers. What is more, in music recording and mixing environments, several people may be in the room at the same time, and all may be involved in discussing the mix. In this case they all need to be hearing approximately the same sound, and so could be led into speaking at cross-purposes if the sound varied greatly from one part of the room to the other due to the spacial limitations of the loudspeaker/room correction process.
The problem with the on-board D to A converters is that if their quality is not at least as good as the converters elsewhere in the chain, they can mask the more subtle differences during the decision-making processes. This is unlikely to be a problem in the worlds of television or video, where the differences between reasonable quality convereters are very unlikely to ever be noticed. In the top end of the music industry, however, in good rooms and listening via high resolution loudspeakers, the differences even between very high quality converters can be surprisingly noticeable. Unfortunately, if the on-board D to As in a monitor system are not of comparable quality, the differences between the better converters may be undetectable. This implies that the monitor systems are not resolving that level of detail, so it can be difficult, if not impossible, to know the true level of quality of the recording.
Whether all this is important or not will depend on the standards that the recording/mixing personnel are aiming for, but even if not all are going for audiophile quality, it is still good to be aware of where the limitations exist. It seems to me that an enormous amount of professionals using such systems are totally unaware of the limitations. I have also heard many people claim that they cannot hear the benefit of many of the better converters, when the fact is that they have simply never heard them in high resolution listening conditions.
Think about the reality: if a pair of self-aligning loudspeakers cost 2,500€, the cost of their on-board converters is not likely to be much more than 30 or 40€ each. How can such converters, and through which all the sound is being judged, be expected to sound as transparent as stand-alone converters costing 50 times more?
Personally, I still like to keep monitor chains analogue, albeit of very high quality. I find that it helps me to get a much better perspsctive on the differences between the different digital parts of the process. Nevertheless, to do this removes the option for automatic room-correction, so the only solution is to revert to acoustic treatment. However, as we have already discussed, this needs space. It also tends to have little secondhand value. (But there again, nowadays, nor does much secondhand digital equipment!) The choices boil down to the importance being attached to the sound quality of the end product.
In Resolution V? and V?? there were articles about the E-Trap, which is an electroacoustic absorber, as shown in Figure 2. Such systems are capable of fixing the very worst problems below about 80 Hz, but they only appear to be capable of making a bad room usable. Nevertheless, perhaps it is unfair of me to say 'only', because making a bad room workable may be exactly what some people need, especially in temporary premises. It would be futile to install them in a room that was already quite well controlled, but if somebody was forced to work in a very lumpy room, then the E-Trap could help to make life tolerable.
Of course, another commonly seen form of treatment in small rooms is the use of various shapes and sizes of open-cell polyurethane foam sheets and blocks. So often, the application of these by relatively inexperienced people can lead to rooms which initially sound as though they are controlled, but in fact a lot of colouration can still exist, which will manifest itself in the recordings, and the rooms can still exhibit gross irregularities. Basically, any porous absorber (such as open-cell foams, and fibres) can only absorb well the frequencies whose wavelengths are less than about four times the thickness of the material. Well, at least that is the case when the material is fixed on a rigid wall. If, however, it is spaced away from the wall, the lowest frequency of reasonably good absorption will be that whose quarter-wavelength is similar to the disrtance from the outer surface of the material to the wall. In either case (thicker material, or a thinner material with an air-space behind), space in the room will be consumed. I hesitate to say that space woulds be 'lost' because the amount of floor-space in a control room is not the be-all and end-all of its function.
Just as a rule of thumb, I usually need an average of about 50 cm all round a room to bring it under reasonable control. In some parts of a room, dependent upon its use and the degree of low frequency control that is required, a metre or more may be needed. To begin with a room of 3 m x 4 m and to expect to end up with a working space of the same size is simply not realistic.
So, even foam treatments need a considerable amount of space if they are to be genuinely effective, but in so many cases thin sheets are glued to walls in the forlorn hope that a well-controlled room will be the result. In reality, all that this usually does is absorb the high frequencies. This may initially give people the impression that the room is rather dead, but the truth is that it will probably still be quite lively in the lower voice region, and the recordings, or the monitoring, will probably sound boxy and unnatural.
Even with sponge blocks in the corners of the room, they usually have too little depth over sufficient a surface area to do what many people expect of them. It is a pity that so any people now believe that a few foam sheets and blocks, on the walls, and listening at close distances via less than top-of-the-line loudspeakers, can give them almost ideal monitoring conditions.
As the industries become staffed with people who are ever more likely to be operators, rather than engineers, they aften fail to see (or hear!) the many down-sides that can be introduced when they are concentrating on the fix for one, particular problem; or when they are concentrating on the single up-side of something that they have just been sold. Perhaps with the same disgrace that now faces the 'free-market rules all' philosophy of the last 20 years or so, and the growing awareness that price and value are not synonemous, some long-lost attitudes in the recording industries will return, and a realisation will arrive that 'doing it all as cheaply as possible' is not a sustainable driving force.
The mass-marketing of products also often tends to seek the lowest common denominators, but artistry and professionalism do not sit happily with this type of philosophy. But, there again, the human race tends to be living in an unsustainable bubble at the moment, and some of the only ways that it can even be temporarily sustained are via philosophies which require ever cheaper products for ever bigger markets. The laws of acoustics, on the other hand, operate on a more Universal time scale, and involve principles that know nothing of the pressures of fashions or marketing. In the end, it is these physical laws which dictate that a great sounding, flexible-to-use studio, in a room of only 30 cubic metres (say 4 x 3 x 2.5) is something only for a wild imagination.

PaulBrewer

Mr Newell also made some corrections to my original post -

"Also, may I comment that you should be using the word 'damped', and not dampened. The first means to lose energy through resistance, the second means to make rather wet."

ICN

studiorat wrote: »

..Now I'd like to throw a spanner in the whole works and make another recommendation, passive loudspeaker membranes can be more effective than convertional membrane systems since loudspeakers are really good at vibrating over a wide range of bandwidths, and they're damped easily. If it's cost effective to cover a wall with them is another question.

Bagend actually make an active absorber basically using loudspeaker that can be tuned as the room requires. http://www.bagend.com/bagend/ETrap.htm I reckon this is the future...

Wow - Thats very interesting.. It reminds me of a Physics experiment that we used to do about Newtons 3rd Law of Motion - To every action there is an equal and opposite reaction.

Makes sense.

ICN

PaulBrewer wrote: »

Philip Neweill has just given me permission to reproduce his article. This is a draft version of what may or may not be in next month's Resolution Magazine.

Improving the Working Acoustics in Small Rooms.....

Excellent - Really enjoyed reading that.

Coincendence that he was doing it at same time.. but I suppose this issue is the bane of a lot of peoples lifes. Its always going to be affecting/effecting someone.

Not sure I'm ready to give up 50/60cm around my whole room just yet though! LOL

PaulBrewer

ICN wrote: »

Excellent - Really enjoyed reading that.

Coincendence that he was doing it at same time.. but I suppose this issue is the bane of a lot of peoples lifes. Its always going to be affecting/effecting someone.

Not sure I'm ready to give up 50/60cm around my whole room just yet though! LOL

"This is a big problem with small rooms, there is little space in which to do anything to control them, Unfortunately, the control measures depend on frequency and wavelength, and not on the size of the room that they are controlling"

That's the essence of the article in my opinion.

studiorat

Very poor article by Newell IMO. In general it is a bit vague and quite broad and very thin on useful information, it would seen to serve no other purpose than quantify his own worth as a consultant.

In fact he states that to deal with low frequencies up to 1m is needed. What happened to Munro's tuned membrane?

I thought you didn't like his work Paul? That's the guy in Spain with the crap studio right?

PaulBrewer

studiorat wrote: »

Very poor article by Newell IMO. In general it is a bit vague and quite broad and very thin on useful information, it would seen to serve no other purpose than quantify his own worth as a consultant.

I thought you didn't like his work Paul? That's the guy in Spain right?

I don't like his studios !

However I like him and the fact that we can agree to disagree and continue to discuss subjects such as this is the mark of a good soul.

The article is, as you say broad but it's an article in a magazine - not an Academic paper and should be read as such.

For more in depth information you can read his books.

PaulBrewer

studiorat wrote: »

In fact he states that to deal with low frequencies up to 1m is needed. What happened to Munro's tuned membrane?

He doesn't use them.

The point is that a Metre or more is necessary - not that that approach doesn't work.

studiorat

It's an article for Resolution magazine! Remember? The one John Watkinson writes for, very poor form. The professional one? Reads like Future Music...

PaulBrewer

studiorat wrote: »

Reads like Future Music...

I've never had the opportunity to enjoy that tome .....

What exactly are your criticisms? Are there factual inaccuracies? Or is it you 'just don't like it'.

I did also point out it's a first draft.

I'll gladly relay your observations to Mr. Newell.

studiorat

The title is "Improving the Working Acoustics in Small Rooms"

I count two solutions, two and a half if you count active monitoring which he disregards. I guess he hasn't got a suss on a good dealership for that yet. One of the problems he mentions is about foot fall from the room above. What the hell has that got to do with the Acoustics of the room? Only a complete idiot wouldn't be able to figure out how to solve that.

I wouldn't say factual inaccuracies just a certain broadness that in Resolution looks more like a badly written advertizing feature. But considering the title and the the fact that there's so few actual solutions mentioned I'd say it's more of a rant.

PaulBrewer

studiorat wrote: »

The title is "Improving the Working Acoustics in Small Rooms"

The working title .

I'd say it's more of a rant

.

Perfect for here then!

studiorat

PaulBrewer wrote: »

Perfect for here then!

In reality there's more useful information in a lot of the posts here, and not just hinted at information as in the article.

A better title might be "Why small rooms are Sh1te and only €10,000 can tell you how to fix it"

It's not even remotely amusing...

PaulBrewer

studiorat wrote: »

In reality there's more useful information in a lot of the posts here, and not just hinted at information as in the article.

Thank You.

madtheory

This is getting a bit silly. Why are some of you being negative about people who have done great work in the field of audio? Is there a bit of irish begrudgery creeping in?

Philip Newell has done some excellent work, for example his analysis and support of research into why the Yamah NS10 and Auratones make such good monitors, and of course his books. It's unreasonable to criticise one article without an awareness of his other work. Clearly, one is not going to learn all one needs to know about studio acoustics from one article. If you want to learn about something, you do research.

IMO it's perfectly reasonable for him to rant about this issue, because it is a real problem.

Ethan Winer answers hundreds of noob posts on gearslutz, often the same questions over and over, and is always polite, but he's only human, so clearly he's not going to answer every repeat question.

And he's not responsible for the actions of others.

He provides free and accurate information on acoustics, including plans to build your own traps and diffusers, even though he also runs a company selling these products. Sounds like a very reasonable bloke to me!

Right, that's my rant over

i57dwun4yb1pt8

sorry about the spelling , im rushing here!

my room is 8 by 8 by 7 high

Ethan winer and the sluts lads were very helpful to me in getting the best from the room as its tiny .

Initial scans using room eq wizard shoowed huge resonant nodes ( maxs and nulls ) at the mix spot
so i re designed the whole room , and used rockwool ( the one used for outer wall insulation - its medium dense)
in side "readybags" which cost a bit .

these are 4 feet by 2 by 6 inches deep

I filled 3 corners wall to ceiling with rockwool "twix bars" 1 foot thick ,
then cover them over wall to ceiling with a vertical ready bag on top of another wall to ceiling.

i also put tww bags behind the mix area and two in front
two at the side
and two on the ceiling corners where wall meets ceiling .

also i covered the celing in foam as all it did was fire hi freq reflectiuons back , and comb filtered the lot .

some more scans and some adjustment of monitor placement and monitor contour controls
gives me a reponce flat to within 6db from 40 to 400 - this is as good as it gets in this cube , and its very useable.

now , the room is very dead sounding , so i have to be careful about the fact that the higher mids can get sucked out

but its a massive masisve improvement on what i had to mix in.

i did lose a lot of space doing it , and its fecking warm in there.

i would say bang a few ready bags ( or even rock wool covered in decorator dust sheets ) around the walls ans this should help the room s high mid ring .

but if you arent bass trapping the corners , you will not get a good bass mix .


if i was to do it again i would put very dense rock wool or heavy foam super chunks in each corner , to lessen the space used.

ICN

Just while its slightly topical.. someone mentioned it earlier



There are what look to be Tubes in the corners of this lots room - Deekline & Wizard. Its from a Computer Music Vid from a while back..

They have them in 2 Corners anyway from looking at the Video - Possibly/Obviously some kind of Treatment. They dont look great.. so they have to serve some kind of purpose?!!

http://img228.imageshack.us/img228/1601/deekwiz.jpg

PaulBrewer

ICN wrote: »

Just while its slightly topical.. someone mentioned it earlier



There are what look to be Tubes in the corners of this lots room - Deekline & Wizard. Its from a Computer Music Vid from a while back..

They have them in 2 Corners anyway from looking at the Video - Possibly/Obviously some kind of Treatment. They dont look great.. so they have to serve some kind of purpose?!!

http://img228.imageshack.us/img228/1601/deekwiz.jpg

They're Bass Pan Pipes , you know the music they play in Arnotts ? Amazing Grace etc.

ICN

PaulBrewer wrote: »

They're Bass Pan Pipes , you know the music they play in Arnotts ? Amazing Grace etc.

Isn't it great how that style of music is becoming a hit with a new generation of kids?

We thought it was dying out down here in Roscommon. There's hope!!


Could I borrow one of your lungs for a Sub part I'm doing with them?

PaulBrewer

ICN wrote: »

Isn't it great how that style of music is becoming a hit with a new generation of kids?

We thought it was dying out down here in Roscommon. There's hope!!


Could I borrow one of your lungs for a Sub part I'm doing with them?

If you look on the back wall you'll see Sombrero Diffusers ...

ICN

PaulBrewer wrote: »

If you look on the back wall you'll see Sombrero Diffusers ...

Cheers - 2 heads are better than one!