Portal Sound Technologies Studio

[PortalSound]

Greetings,

First time here so if I am in error with anything please let me know.

My current studio is as per the attached PDF drawing by Aurelex-free room analysis. I have installed the recomended panels and located my nearfields-LSR 305_ in the triangle configuration with the length of 55". I also have a sub_LSR 310- located directly behind me at the same 55".

I also bought the ARC system and "balanced" the room using this. Huge null at about 100hz but allegedly it was corrected whti this.

I have been reading alot about Studio Designs as I was considering converting a 12'x12' storage shed out back into a studio but the size is just completely wrong per what I can understand from the info I have tried to comprehend.

On to my Point.

I would like to add some diffusers and Bass traps to the attached design to make this room as good as it can be. I would also like to flush mount a new set of mid field monitors while keeping my Near Field set up.

Please don't shoot me but I would like to take a somewhat different approach here. I would like to use the theory of off site construction of "cabinets"- for the lack of a better word- in sizes that would fit the requirements but with the premise that when I do build the perfect room I can reuse them. In other words, build them in modules with "filler" pieces to adapt them to the actual room dimensions.

And Leave the existing walls as they are:

Walls: 1/2" gyp board on 4" studs at 24" centers no insulation.

Floor: Standard 2nd floor house construction currently with carpet but I will change this to any laminate flooring recomended.

Ceiling: Standard 1/2" gyp board insulated with 12" of blow in insulation.

This would seem to fit way more people than a custom build while allowing them to:

Not alter the home for resale.
Allow them to take these modular pieces with them.

I am sure this is not correct or the "best way" and I may be better off with what I have. If this approach makes my room substantially better I am ready to go. I have a millwork company who will make these modular pieces for me.

Also to be absolutely honest, if this works and It does indeed make my room better I may form a company to make these modular pieces that can be shipped unassembled and installed on site with the minimum amount of jobsite labor as that is what drives up the cost.If anyone who helps wishes to be involved with this all options are open.

Thank you for your time and I await your positive response. No worries if the end result is "Piss off".

Best

Mike Thompson
Portal Sound Technologies

[Soundman2020]

Hi there Mike.

First time here so if I am in error with anything please let me know.

Please read the forum rules for posting (click here). You seem to be missing a couple of things!

That said, it's an interesting case you bring up, and one that happens too often. Basically, there's no such thing as a "one size fits all" automated acoustic treatment plan that you can buy in a box. It will probably help a bit, but it won't make your room good. So starting from that point....

My current studio is as per the attached PDF drawing

So it's basically a rather small "corner control room" that is not symmetric. That's a difficult one to treat correctly, even for an experienced acoustician!

I have installed the recomended panels

I have always found it strange that these automated free acoustic analysis companies always seem to recommend only their own products! I wonder why they don't ever seem to recommend anything that you can make yourself, or buy from another company? I'm SURE it has nothing to do with profits!

in the triangle configuration with the length of 55"

The "triangle configuration" is a myth. Yes, you do want to have the speakers the same distance from your head, but there is no need at all to also have the speakers set that same distance apart, and even less reason to have the speakers aiming at the middle of your head. Think about it: If the speakers are aimed at the middle of your head, then your EYES are on-axis to the speakers, but your EARS are off axis! Not by much, sure, but that's a bad arrangement. It turns out that the best arrangement is to have the speakers aiming at a spot about 18" behind your head, which means that your ears are pretty much on-axis to the speakers. In fact, with that arrangement, the acoustic axis of each speaker is just grazing past the edge of your ear lobe, which puts it in about the best spot, psycho-acoustically.

Also, the diagram they sent you shows the speakers spaced away from the front wall, but if you do that in a room as small as yours, you will have a very large SBIR dip in the frequency response at some point in the low end of the spectrum, probably around 100 Hz, that will be impossible to fix. The correct location for speakers in a small room is to have them right up against the front wall, with only about a 4" gap behind them and a 4" thick panel of suitable porous absorber in that gap. That arrangement forces the SBIR dip higher up the spectrum, to a point in the mid range where it CAN be fixed, and the porous absorber fixes it. This is basic acoustics, but the automated foam selling system is not able to figure that out, since you need actual knowledge of acoustics, and actual understanding of speakers, rooms, and effective treatment.

Even better than having them up against the front wall, is to flush mount the speakers IN the front wall...

Also, the "perfect" 60° angle for speakers is another myth: Every room is different, speakers are different (different Q, different off-axis response, different frequency spectrum, etc.), so the angle needs to be figured out differently for every room and every speaker. When I design a studio control room, I start with the speakers and work outwards from there, designing the room around the speakers. That's the only smart way to do it. Very often the angle ends up NOT being 60°...

I also have a sub_LSR 310- located directly behind me at the same 55".

Behind????? I saw that noted on the diagram they sent you, and I had to laugh.... Hoo boy! Having the mains in front of the mix position, and the sub between the mix position and the client couch...! Ummmm....

I also bought the ARC system and "balanced" the room using this.

That's unfortunate. Once again, automated systems CANNOT fix room acoustics.

Don't get me started on the "room correction" hype ...

Argghhh!!! Too late! You got me started!

OK, so here's the issue: It is impossible to "correct" a room using equalization filters. It cannot be done. Period. That's a pretty blunt, emphatic, and categorical statement, so it needs some blunt, emphatical, and categorical evidence to back it up! Here goes:

Yes, it is possible to adjust the intensity of some frequency bands (which is what any equalizer does!), but that does not "correct" the room. It compensates for SOME types of acoustic problems, but does NOT compensate for the most important ones. Note carefully what EQ does: it modifies the FREQUENCY RESPONSE of the room, but frequency response is NOT the biggest problem in most small rooms. Time domain response is the biggest issue! In other words: how the sound field dies away AFTER the sound stops. There is nothing you can do with an equalizer that will modify what happens inside the room after the sound has already left the speakers! Sort of obvious when you think about it.... but the "room correction" manufacturers don't ever bother telling you about that! I wonder why? Could it be for the same reason that the automated acoustic panel selling software never recommends products made by someone else?

So, time domain is the problem. The goal for a control room is for all frequencies to die away at the same rate, and that rate is governed by the size of the room. There are simple equations for calculating that, and it is usually expressed as "RT-60", meaning "60 dB Reverberation decay Time", or how long it takes each frequency band to decay by 60 dB from it's original level. In ALL control rooms, you want that to be "flat". If you plot the decay times on a graph for each frequency band, you want the line to be flat, or nearly flat. It can rise a bit in the low end, and sink a bit in the high end, but most of it needs to be flat. That means that the room treats all frequencies equally, without "stretching out" any of them over time, nor "cutting short" any of them. They all need to decay equally, and evenly, with only minor variations between the bands. For an empty room, EQ can do NOTHING about that, because it's a problem that occurs in the time domain, not the frequency domain. Zero. Zilch. Nada.

This is obvious, when you think about it. Equalizers cannot adjust time! They can only adjust frequency.

I'm not saying that frequency response isn't important: it is, and you should make every effort to get that reasonably flat as well, but for a control room, the time domain response is first and foremost. And that can ONLY be fixed with acoustic treatment. The CORRECT acoustic treatment, placed at the CORRECT locations in the room. Once the room has been fully treated, as far as it can go, THEN you can use EQ to put the icing on the cake, by adjusting the frequency response. And in that situation, it actually is possible for the EQ to have an effect on the decay times. Not because the eq can affect time! But because it only works IF the room has already been treated correctly, to the point where the room exhibits a specific characteristic known as "minimum phase". A room that is truly "minimum phase" has a very interesting mathematical property, in that the impulse response is now mathematically reversible. If a room is minimum phase, you can look at the sound field in the room at any point in time, and predict what it will be at any other time in the future, or what it was at any point in the past. You can sort of "reverse time" in the equations (sort of making time "flow backwards"), and arrive at the original impulse that caused the sound field. And if you can do that, then you can modify the original impulse with EQ such that you get whatever future situation you desire. That does NOT work for any other room: only for minimum phase rooms. In this one specific case, EQ can affect time domain response because of the reversible mathematics of the "transfer function". In this one specific case, EQ can also be used to deal with SOME forms of time-domain problems.

But that DOES NOT WORK in a room that has not been treated to make it "minimum phase". It just doesn't. The transfer function is not reversible for those rooms, so it is mathematically impossible to use EQ to fix time-related problems.

But the manufacturers of automated room correction software and hardware seem to conveniently forget to tell you about that... How curious! I'm SURE it's not because they want to fool you into thinking that their product can fix an empty, untreated room! I'm sure they are far more honest than that, and would NEVER want you to buy stuff that won't actually work in your room... ...

Here's a real-life case of near-perfect acoustic response in a properly treated room that also had digital tuning applied: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 . I designed that room from the beginning to have the best possible acoustic response, we treated it to the max, doing every possible thing with physical acoustic treatment to get it as close as possible to minimum phase, and then I spent many, may hours carefully tweaking the precision digital equalizer to deal with the last remaining issues in the room. That's about as flat as you can reasonably expect in a studio, in both frequency domain response, and time domain response.

Huge null at about 100hz but allegedly it was corrected whti this.

That's actually impossible. I did notice that you worded that very carefully, saying that it was "allegedly" corrected, and hence I can see that you are not at all convinced that it really is fixed! And that's good because it is not fixed, and I can tell you that directly, without even needing to look at the acoustic data. The reason is simple: it is impossible to fill in a room null with EQ!

A null in room response is caused by one thing alone: phase cancellation. In other words, at the location where the mic is, the direct sound from the speakers reaches the mic in-phase, then a short time later a reflection of that same sound arrives at the mic, out of phase. The two sound waves cancel each other out, creating a null. If you try to fix that with EQ by boosting the frequency where it occurs, then you are simply making the null BIGGER! You are pouring MORE energy into both the direct wave and the reflected wave, so the cancellation is even more effective, and the null gets deeper. You CANNOT fill in a null... except in a minimum phase room, and obviousness, if you have phase cancellation going on, then the room is not minimum phase!

If you try to fill in a null, you get one of two results: either you make the null deeper, or you create an unstable condition which will cause the room to "ring"
at that frequency, even though there is no room mode or resonance at that point.

Here's what happens if you try. I deliberately did some tests in a room a while back, to show what actually happens.

First, this is the frequency response graph, where it clearly looks like I fixed the problem!

FBQ-004-L-vs-004-Bad-Fil.png

The red curve is the frequency response before I added the filters, and the blue curve is after I add EQ. Amazing! It is fixed! You can clearly see how much smoother the blue curve is, so I must have done a really great job there, right? The room must sound a lot better, right? Wrong. It sounds like crap now. Here's why:

Look at the time-domain response here, as shown in the waterfall plot. First before I applied the filters:

FBQ-004-L--result--WF-18..500-GOOD.png

And now after I applied the filters:

FBQ-004-L--result--WF-18..500-BAD-FIL.png

Ooops! I caused a major ringing issue! The frequency null is filled in, yes, but because the room is NOT minimum phase, that extra energy I added had to go somewhere, and it sure did: it ended up in the time domain, due to the phase shift...

Another way of looking at the same data, as a spectrogram. First, before applying the EQ:

FBQ-004-L--result--SP-18..500-GOOD.png

And now, after applying the EQ:

FBQ-004-L--result--SP-18..500-BAD-FIL.png

With that one, I realized that I had not quite hit the frequency perfectly, and I was also overdoing the intensity a bit too much. So I did some very careful tweaking to hit the null frequency exactly, spot on, and getting the exact intensity to flatten it perfectly: and this is what happened:

Gareth-BADFIL-007--SP.png

You can clearly see that, even though I'm hitting the exact frequency, dead on, it still does not fill the null! It only causes ringing. Because it is IMPOSSIBLE to fill a null!

Here's why:

Gareth-BADFIL-007--FR+P.png

That's the frequency response curve (darker gold color), but I also added the phase response curve, in the light yellow color. As you can see, at the exact point where the dip is happening, there's a huge, mighty swing in the phase of the signal: look at the scale on the right edge of the graph. The phase flips instantly from -180° to -450°, which is a phase change of 270 degrees. Therefore, any energy you add to that null will NOT flatten it, because the energy arrives 270 degree out of phase, and goes into that ringing instability, instead of filling the hole.

You CANNOT fill a frequency dip with EQ. You might think you did it, if you only look at the frequency response curve, but when you look at the phase response and the time domain response, you see what a huge mess it actually makes. And curiously, most "room correction" products only show you the frequency response.... I wonder why?

Excuse the long rant, but I did say not to get me started! It really annoys me when I see glowing adds for room correction devices, with wonderful marketing hype...

The other issue is that, even if you do it right, it still only works for one location in the room. You "correct" the point where the mic is, but at the expense of all other locations in the room.

There's no such thing as a free lunch. And there's no such thing as "room correction", especially a room that has not been treated to the hilt.

If you want to get your room to actually work correctly acoustically, we can help you do that. First, you'll need to do a simple acoustic analysis on the room and give us the data, so we can analyze it. Here's how: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122

I would like to add some diffusers and Bass traps to the attached design to make this room as good as it can be

Bass traps: Yes! absolutely! That should be the very first treatment item in any small room... yet, curiously, the plan you were sent did not include any bass trapping... Not sure why!

Diffusion: No. The room is too small to be able to use diffusion. You are limited to basically absorption and reflection. Those need to be balanced correctly to get the frequency response and time response as flat as possible.

... while keeping my Near Field set up.

That's another myth!

Don't get me started on the "near field monitor" myth....

Darn! Too late! You got me started....


Because there's actually no such thing as a "near field" monitor! And you should NEVER listen in the "near field" anyway!

Bold statement? Yep. But true. Here's why:

The "near field" is a property of the ROOM, not the speaker. This comes from the book "Architectural Acoustics":

what-near-field-really-is.jpg

That's pretty clear, isn't it? That's from a leading text book on acoustics, not on marketing hype, so it tells the truth about what "near field" actually means.

If you say that a speaker is a "near field" speaker, then you are using pure marketing drivel, not actual technical term. In fact, try googling the term "definition of near field monitor", and be shocked: You'll notice that is no technical definition at all! It's a marketing term, not an acoustics term.

As you'll note in that image above, it clearly says: "Sound pressure levels can fluctuate dramatically in the near field .... sound pressures cancel and enhance each other near large reflective surfaces [such as a desk, console, etc.], so sound pressure level measurements should be avoided in the near field." I kind of think that's what our ears do: they make "sound pressure level measurements".

So according to Architectural Acoustics, you should not try to listen in the "near field", since levels fluctuate, and pressure cancel each other out, or enhance each other... So why on earth would anyone make a "near field monitor", and tell you to listen in the "near field"? ??? Beats me...!!!

Not convinced? Then maybe listen to what one of the world's leading experts on speakers says: I quote Floyd Toole himself: "In recording control rooms, it is common to place small loudspeakers on the meter bridge at the rear of the recording console. These are called near-field or close-field monitors because they are not far from the listeners. ... the near field of a small two-way loud-speaker ... extends to somewhere in the range 21 in. to almost 6 ft (0.53 to 1.8 m). Including the reflection from the console under the loudspeaker greatly extends that distance. There is no doubt, then, that the recording engineer is listening in the acoustical near field, and that what is heard will depend on where the ears are located in distance, as well as laterally and in height. The propagating wavefront has not stabilized, and as a result this is not a desirable sound field in which to do precision listening, but as they say, perhaps it is “good enough for rock-and-roll.”

Your honor, I rest my case! As the man says: "this is not a desirable sound field in which to do precision listening".

OK, maybe this calls for a more complete explanation:

If you set up a speaker at one end of a large room and play music through it, that sound spreads out through the room, bouncing back and forth between the room boundaries and objects in the room. If you suddenly turn off the speaker, that sound continues to bounce around for a while, slowly dying away. How long that takes depends on several factors, but the point is that the sound does NOT stop instantly when you cut off the speaker: it carries on "reverberating" around the room. And that reverberant field is there all the time, not just when the speaker is off. When the speaker is on, that "reverberation" is obviously still taking place, and still filling the entire room, along with the direct sound from the speaker. The sound that remains when you cut off the speaker is called the "reverberant field", and the level is more or less even, and constant, throughout the room (this is a large room that we are talking about). It doesn't matter where you are in the room, as soon as you cut the speaker off the remaining level is roughly the same all over, since it is just reflections that are bouncing around randomly.

So with the speaker turned on, if you go all the way to the other end of the room to listen, as far away from the speaker as you can, then what you will hear is practically all "reverberant sound" that has been reflected off the walls / floor / ceiling / furniture / etc., and practically nothing that comes directly from the speaker. Everything you hear has bounced off at least one surface before reaching your ears, and most likely has gone through several such bounces. So you are totally in the reverberant field.

On the other hand, if you were to put your ear right in front of the speaker, just a few inches away, then what you hear is practically all coming directly from the speaker, and almost nothing at all from the room. Everything you hear has not touched any room surfaces, and is exactly what came out of the speaker. In this case, you are totally in the direct field from the speaker.

The point in the room at which the reverberant field and the direct field are exactly the same intensity, is called the "critical distance".

This isn't just a theoretical concept: it can be measured in practice. In that room, use a sound level and stand as far away as possible from the speaker while it is playing at a constant level. Move towards the speaker slowly and watch the level on the meter. Throughout most of the room the level will remain the same, since you are measuring the reverberant field, which is roughly equal throughout the room. But eventually as you get closer to the speaker, the level will start rising as the meter "sees" mostly the speaker. At the point where you get a 3 dB increase, that is the "critical distance" for that room. Any closer than that and you are in the "near field": Any further away and you are in the "far field" or "reverberant field".

It's that simple.

As the image I posted above shows, there's a region between the near field and the critical distance, called the "free field", where things are nice and smooth. That's the best place to be.

There's a lot of people who should know better than continue to buy into the "near-field / mid-field / far-field" marketing hype. Fact is, those are all just fictitious names made up by manufacturers, and gullibly swallowed by some sound engineers, studio owners, and producers, who never bother checking. Most of those would probably be shocked to learn that there is no technical definition for what constitutes a "near-field monitor", or a "far-field monitor", and even less for the mythical, non-existent "midfield". If you don't believe me, do a google search for "technical definition of near-field monitor"... Enjoy your search....

Here's a smattering of definitions that I've picked up over the years, not one of which is true:


"Near-field monitors are short throw, narrow dispersion, limited range units."
"Nearfield is a reference to the range of frequencies the speaker is capable of replicating."
"Nearfield monitors are designed to be positioned approximately one to two meters away from the listener"
"Near-field: a compact studio monitor designed for listening at close distances, typically between three and five feet"
"Nearfield monitors are designed to sit on or just behind the meter bridge of a mixing desk, within a couple of feet of the engineer"
"Nearfield monitors are small speakers which you sit fairly close to."
"Nearfield is if your ear is closer to the speaker than it is to any reflective surfaces."
"The whole point of small near field monitors is that you sit close enough that you don't need a treated room. Amazing how many people don't seem to get that"
"Near-field studio monitors are small speakers that minimize the effects of your room on the sound source."
"For nearfield monitors, you need a listening distance that's at least 3 times the distance between the woofer and tweeter"
"Near field monitoring is a way to sit closer to your monitors with the idea that sitting closer to the speakers say 3'- 4', will reduce the sound of the room in the mix."
"Nearfield simply means "close distance."
"Nearfield means so close that the SPL no longer increases if you move even closer."
"Nearfield means less than 2.50 meters
"Near field is the critical listening distance"
"Nearfield means that your ears are closer to the speakers than they are to any of the room boundaries".
"Near field refers to the size of the monitor in relation to the listening distance"
"Near-Field monitors are designed to be placed less than 6 feet away from the listener."
"Near field listening: set them up 4 feet apart, from 4 feet away. They will sound great regardless of the room from that close".
"Nearfield monitors"? = No bass, no hope of bass, let's not pretend."

What a wonderful hodge-podge of garbage answers! Most are totally off, a couple get sort of close, but they are all still absolutely wrong! And mostly they contradict each other. The worst thing is, all of those come from "experts" offering their opinions on how to set up speakers and rooms...

The issue is that there's no such thing as a "near field" monitor, since the term "near field" refers to the ROOM; not the speakers. If your head is closer to the monitors than the critical distance (and free field) for the room then you are in the near field. If you are beyond the free field or the critical distance, then you are in the far field. Period. That's it. The "critical distance" is a well defined technical term that can be predicted mathematically, and it can be measured physically and easily. There's no question about where it is, or what it is. That distance varies for each room, and each set of treatment, but does NOT vary for different speakers in the same room. For a smallish to medium room that is treated one way, the entire room might be in the near field, regardless of what speaker you use, but if you take out that treatment then the near field might only extend a couple of feet beyond the speakers. In a small, badly treated room that is poorly laid out, there might be no free field at all. And in a large room, the free field might extend several meters, starting quite close to the speakers.

There is nothing at all that you can do to a speaker to ensure that it will always be a near-field monitor, since that depends entirely on the room, and also on where you place the speakers and your head in that room.

And as both Floyd Toole and Architectural Acoustics point out, the near field is a terrible place to listen!

Sorry about the rant again! But my point is that you can use pretty much whatever speakers you want to use in your room (within reason!), regardless of what it says on the box they came in. You do not have to listen close to near-fields, and you do not have to be 20 feet away to listen to far-fields or "mid-fields". And you can soffit-mount pretty much any speaker you want to, with only a very few exceptions. So chose the best, acoustically flattest speakers you can get, with the spectrum range that you need for your music, put them in properly designed soffits at the correct locations in the room, and then design the room around them, and treat the room according. If you like your LSR 305's, then keep your LSR 305's!

And if you REALLY want to get your room as good as it possibly can be, then yes, absolutely, DO flush mount your monitors! That's the best single thing you can do to any room, and pretty much any speakers. The vast majority of studio monitors can be flush mounted, with very few exceptions.

Please don't shoot me but I would like to take a somewhat different approach here. I would like to use the theory of off site construction of "cabinets"- for the lack of a better word- in sizes that would fit the requirements but with the premise that when I do build the perfect room I can reuse them. In other words, build them in modules with "filler" pieces to adapt them to the actual room dimensions.

That's actually the normal way of doing DIY treatment for studios. First, analyze the room with REW to see what it needs, then build modules to deal with the biggest issues, then analyze again, build more, analyze - build - analyze - build - analyze - build until you run out of money, or space in the room, or get perfectly flat response....

But maybe I misunderstood you, and you are talking about building your flush mount or "soffit" modules outside of the room? That won't work, unfortunately. Soffits (flush mount modules) have to be extremely heavy, by nature. A light soffit would be rather silly. It would be way too heavy to build outside, then try to carry in. It would also be far too big too fit through the door. So for your soffit modules at least, you'll have to build those inside the room.

But most of the other treatment can be built outside, then brought in and positioned correctly.

And Leave the existing walls as they are:

That's fine mostly, except that you REALLY should fix your symmetry problem. That can't be fixed with EQ, and and can't be fixed fully with treatment.

Walls: 1/2" gyp board on 4" studs at 24" centers no insulation.

No insulation! WHY???? So you created walls that are basically drums, that resonate and trash both your isolation and your room acoustics? You REALLY should consider fixing that!

currently with carpet but I will change this to any laminate flooring recomended.

Definitely! The carpet is not doing you any favors at all, and is likely making things worse. So you will need treatment on the ceiling.

I am sure this is not correct or the "best way" and I may be better off with what I have

It's fine, and is a common way of treating hone studios.

If this approach makes my room substantially better I am ready to go

I have a millwork company who will make these modular pieces for me.

I'm not sure why you would need a millwork company: You can build the modules that you will need very simply, from wood, fabric, and insulation. A good carpenter would be a better choice.

if this works and It does indeed make my room better I may form a company to make these modular pieces that can be shipped unassembled and installed on site with the minimum amount of jobsite labor

You'd be competing with a lot of other companies that do the exact same thing! One of those is called "Auralex"... And you'd have the same problem that all of those companies have: There's no such thing as "one size fits all". There is no one single treatment that will work in all rooms, for a very simple reason: all rooms are different. Each room needs it's own analysis to determine what it needs, then specific devices to deal with those exact issues.

When I say "Each room needs it's own analysis to determine what it needs", I don't mean a rough sketch with a few dimensions on it! I mean a proper detailed analysis of the actual room's real acoustic response, using a tool like REW, then analysis of the acoustic data, then a series of "design - install - analyze - design - install - ..." etc., repeated until the desired outcome is attained (as specified in ITU BS.1116-3).

Thank you for your time and I await your positive response

Done!

No worries if the end result is "Piss off".

Not at all! Hopefully the above will get you on the right track. Because it does not come from a company that is out to sell you something: it comes from someone who designs and builds studios for a living, and doesn't really care if you take the advice or not: it's no skin off my nose if you use it to treat your room wonderfully, and I'd actually be VERY happy if you did start a company to make serious acoustic products that could be tailored to fit specific issues, or perhaps a range of products to choose from, where each one is specifically designed to deal with a certain problem, and there's someone at the company that can read the REW data and specify which product is needed for each customer in which location in the room. That would be a GREAT business model, and something that is sorely lacking in the industry right now. It would be even better if that company would be totally honest, and tell the customer when none of their own products will do what is needed, and to direct the customer to another company that does have the right product, or show the customer how to build the product himself. That would be excellent! An honest acoustics company that makes tailored products and tells you when their products won't do the job. If you do start such a company, then please let me know: I'd probably be recommending that some of my customers should buy your stuff, if it is applicable to their needs. That would make my job easier, for sure.


- Stuart -

[PortalSound]

Stuart,

Thank you very much for taking the time to post such a detailed and informative response!

It is greatly appreciated.

It seems that my room is pretty compromised so on to plan "B" as I hate fighting a losing battle.

Plan "B":

I talked with my significant other and have the green light to build a room in the garage. From preliminary measurements: 22 feet wide by 22 feet long by 9 feet high with a concrete floor, insulated stud walls with pressed chip board inside- walls and ceiling.

Also has approx 8 foot deep by 10 food wide by 8 foot tall extension on the rear to accommodate my boat- alas I will have to store her elsewhere.

I have been mixing in the box for about 5 years as a hobby with some sucess. Retired this year so I am starting to build my hobby into something to keep me out of trouble.

So an open slate. I am not interested in getting into much recording- no drums for sure, but probably need some overdubbing space for vocals etc.

I would appreciate it if you could point me in the right direction on design of a good room. Also those LSR 305's have a back firing bass port so probably not good for flush mounting which I would like to have.

Thank you again for everything and I look forward to your response.

Mike

[PortalSound]

Stuart,

While I am building my new room I would like to get my existing room better.

I read the room analysis post and I can do this with a couple of quick questions:

1. The LSR 305 has a back firing bass port. Where should I place them in the room for the initial test and if I need something behind them what do you recommend?

2. Should I use the sub for the initial test?

3. Should I leave the Auralex stuff on the walls/ceiling for the initial test or remove it?

4. My current interface is limited to 48kz conversion. Will that work?

Thank you for everything.

Mike.

[Soundman2020]

I talked with my significant other and have the green light to build a room in the garage.

That's good news! You should have more possibilities in there.

From preliminary measurements: 22 feet wide by 22 feet long by 9 feet high with a concrete floor

Excellent size! The square shape is a problem, but that can be dealt with when you build the "inner-leaf" room / rooms.

So an open slate.

The best way to have it.

I am not interested in getting into much recording- no drums for sure, but probably need some overdubbing space for vocals etc.

Do you want to have one single large room, or split it up properly into a control room and a tracking room? There's probably enough space to do that. A control room needs to be at least 215 ft2 floor area, ideally (it can be smaller, and I have designed several rooms smaller than that, successfully, but that's the "optimal" minimum, according to internationally recognized specs). So you have enough space for a nice sized control room, as well as a small tracking room, or vocal booth, or iso booth. Is that what you are thinking?

I would appreciate it if you could point me in the right direction on design of a good room.

If you want to get a customs design done for you, then there's a few of us here on the forum that offer that service. Talk to John Sayers himself first: send him a PM (Private Message), and ask him for a quote for designing your place.

If you want to do it yourself, then I'd suggest two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. The first one will give you the background in acoustics that you need to be able to design a studio, and the second one will give you the basics for actually designing it and building it.

Also those LSR 305's have a back firing bass port so probably not good for flush mounting which I would like to have.

Not a problem! Many people think that rear-ported speakers cannot be soffit mounted, but that isn't true. They CAN be soffit mounted, if the soffit is designed to deal with it correctly. For example, take a look at the speakers in Studio Three in the link I gave above ( http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 ) Those are Eve Audio SC-407's, which have huge bass ports on the rear. Yet, there they are, mounted in soffits, and performing awesomely... Also this one: http://www.johnlsayers.com/phpBB2/viewt ... 5&start=30 . Those are Mackie HR824, which are also rear ported, yet performing great. There are many other cases I could show you, but those two alone prove it can be done. I think there might even be someone who did it with LSR-305's.... I seem to recall that a forum member did that a while back, but I don't remember who.

The issue is simply to design the soffits to match the needs of the speakers.

So if you'd like to keep your LSR305's in soffits, then you can keep your LSR305's in soffits!

1. The LSR 305 has a back firing bass port. Where should I place them in the room for the initial test and if I need something behind them what do you recommend?

Still up close to the front wall, regardless of the port. About 4 1/2" away from the front wall (12cm), and with 4" of something like Owens Corning OC-703 between the rear of the speaker and the front wall: Yes, the rear port will be aimed at, and very close to, the insulation, but that's fine. It is tuned very low, and will still work fine like that.

I'd have to spend some time figuring out the correct layout (locations and angles of speakers and mix position), and I'm out of time right now, and I also don't ave all the dimensions of the room to be able to do that. PM me with the dimensions if you can, and I'll take a look at that later, to come up with the ideal locations.

2. Should I use the sub for the initial test?

Yes, but not where it is now! Put it up against the front wall as well, spaced away a few inches, and facing to the left or right (it doesn't matter which), and NOT centered on the wall: offset a foot or so to one side or the other (which way foes not matter: either left or right). Once again, I can give you a better location if you give me all the room dimensions.

3. Should I leave the Auralex stuff on the walls/ceiling for the initial test or remove it?

Leave it on for now. It's doing something, certainly, but not enough.

4. My current interface is limited to 48kz conversion. Will that work?

That's fine, yes. The Nyquist frequency for that is 24 kHz, so it will work fine up to the 22 kHz top end that I mentioned in those instructions. Even a 44.2 interface will still do a decent job at 22 kHz, which is why I chose that for the instructions! It will work with pretty much anything.

I'd suggest that you do one test exactyl as you have the room right now, the way they said to set it up, so we can later compare that after you get it done correctly, to see what a difference it makes...

So do one set of tests without changing anything, then after I send you the layout to try, do another set of tests like that.

If you are able to take off the treatment you have easily (ie, if it is just hung in place, not glued or otherwise attached permanently), then by all means to another set of tests with the room completely empty, so you have a baseline test of how the room reacts naturally. That way, we can also see how well the treatment that you have is doing! I'd love to do a comparison between the untreated empty room, the treated room they way they told you to do it, the treated room with the optimal geometric setup, then the final outcome after you have all the REAL treatment in place. It could be quite interesting, I think!

Also, for all of this testing, make sure that your ASC is NOT in circuit: we want to see how the room itself is reacting, without any EQ applied. You could do yet another set of REW tests with the ASC operating, so we can take a look at what it is actually doing vs. what it says it is doing. That could could also be interesting!


- Stuart -

[PortalSound]

Stuart,

I will gather the oc 703 and the SPL meter and do the tests.

I will move the sub and the monitors per your suggestions.

I have a drop box and will pm you when all is done- probably a week or so as I have to wait for the 703.

I will do these tests:

1. Per the instructions and without the ARC. Auralex panels up

2. Per the instructions with the ARC. Auralex panels up.

3. Per the instructions and without the ARC. Auralex down.

4. Per the instructions with the ARC. Auralex panels down.

Thank you for your help.

Mike

[PortalSound]

Stuart,

I made a .xls file-attached-showing the room dimensions.

Consider it an open slate. If its not too much to ask can you help me in locating my monitors and sub in the room?

It would be greatly appreciated.

Mike

[PortalSound]

Stuart,

Attached is an .xls file showing the interior dimensions of the room I am currently using.

Would you consider to locate the monitors and sub where you think is best?

Also locate the microphone where you think it would give the best readings?

If I was in Chile I would buy you a beer.

Mike

[PortalSound]

Stuart,

I am taking several steps to grow my mixing business including upgrading my hardware and software, designing a new website and expanding my business to include live sound consulting.

I now understand that building a mixing room in my garage will take several months as I can only devote about $1,000 per month to that build. I also realize that I really should pay for a design from you or John for this.

This means that I have to either upgrade my current room upstairs or modify the shed in my back yard(drawing attached) to allow me to continue mixing for my current and future clients in the interim.

The mixes I have made in my current room are good but not great and I want to take the room out of the equation as much as possible so that I can break thru to the next level.

I can devote that $1,000 per month to make either interim room better and once that is done I can then devote those funds to building the real room in my garage.

First question: Which room has the best potential for a better outcome?

Second question: I do not want to ask you to help if this is asking for more than you should do without charge as your knowledge has value. But I will need help for sure as I do not have the knowledge nor the experience required. Nor can I afford to end up worse than I am now. PM me if you feel its better.

Third: I took a look at building 2 each 2'x4'x4" thick panels with 4" 703 and it seems that the material cost vs purchasing 2 panels(gik 244 bass traps) only saves about $45.00 so probably I will just buy most of the treatment if is available unless the savings is enticing.

I thank you again for everything and look forward to hearing from you.

Mike

[PortalSound]

Stuart,

Here is the link to my Dropbox for the Mdat files:

https://www.dropbox.com/s/igymuafry9zx5 ... .mdat?dl=0

Let me know if these work.

Mike

[PortalSound]

Stuart,

Here is the room with speaker placement, mic placement etc.

Mike

[Soundman2020]

I downloaded the data, but there seems to be a problem with the way you did the soundcard calibration. That's not valid data in there.

Here's what your soundcard calibration curve shows:

suspect-soundcard-cal.png

And here are four correct soundcard calibration curves I chose at random, from among the many that I have on file, from my customers:

good-soundcard.png

good-soundcard-2-MKCAN.png

good-soundcard-3-CRTZ.png

good-soundcard-4-OWNUS.png

Those are all typical soundcard calibration data. So there's a problem with the way you did that. So you need to repeat your soundcard calibration procedure correctly, and send me the new file.

You don't need to repeat the actual room tests: just the loopback test for the soundcard calibration. That data is only used by REW to adjust the display of the acoustic data: it isn't used in the actual testing procedure.

- Stuart -

[PortalSound]

Stuart,

See if this one is right

https://www.dropbox.com/s/fez1tf93jt46l ... .mdat?dl=0

Think I was using the Mic instead of just looping it.

Mike

[Soundman2020]

It looks like you are doing the calibration correctly now, with the loop-back, but somewhere in your system is a massive bass roll-off. Probably in your EQ settings.

Here's what you are getting:

steep-rolloff-soundcard-cal.png

As you can see, there's a large roll-off at about 18 dB/octave, starting at around 100 Hz. I suspect that you have a low-cut filter applied somewhere. Check your full signal chain to find out where this EQ is happening, and turn it off. And since it seems to have been applied for the measurement tests as well, in this case you really will have to repeat them, in addition to repeating the calibration process, after you eliminate the EQ.


- Stuart -

[PortalSound]

Stuart,

So sorry for wasting your time here. I'll check everything and re run the tests again tomorrow.

Please accept my apologies.

Mike