doing room measurements before bass trapping?

[btroberts]

Hi,

I am just wondering what the point of measuring a room with say room eq wizard is before embarking on a diy bass trap project..In the end all I can do is Basstrap the room anyway isnt it, and this is always going to be behind the monitors on the reflection points, the corners and the back of the room right? so what use is measuring it given I'lll likely have little option as to what I do?

Please forgive my ignorance, I was going to just pick a project, get the materials in and start building but I thought I'd better check first as I will need to buy a measurement mic if I need to do measurements first.

[explorer]

It is good to measure before so you can see what problems you have and use the information to assess whether your treatment is working. It's also cool to see how things change.

[Torea]

Originally Posted by btroberts

I will need to buy a measurement mic if I need to do measurements first.

Speaking of which, I'm trying to find a measurement mic that I can use with the Room EQ Wizard. I was thinking of the ECM8000 (since it's cheap and I've seen it recommended here) or a Radio Shack SPL meter (same price, easier for me to get). The RadioShack one only has an RCA out. Will that work with the REW?

Thanks

[Ethan Winer]

Originally Posted by btroberts

I am just wondering what the point of measuring a room with say room eq wizard is before embarking on a diy bass trap project..In the end all I can do is Basstrap the room anyway isnt it

Yes! Though measuring helps to see how bad the room is now, and how much better it got after treatment. But your basic premise is correct, because the solution for most rooms is the same no matter what you measure.

--Ethan

________________
The Acoustic Treatment Experts

[Ethan Winer]

Originally Posted by Torea

I'm trying to find a measurement mic that I can use with the Room EQ Wizard.

Here you go:

Comparison of Ten Measuring Microphones
Room Measuring Primer

--Ethan

[Torea]

Originally Posted by Ethan Winer

Here you go:

Comparison of Ten Measuring Microphones
Room Measuring Primer

--Ethan

Thanks Ethan! I saw your response in a different thread on mics but it didn't say if the RCA could be hooked up to the REW. And of course, silly me, I checked the REW info after posting here and noticed they say the RadioShack will work. Thanks for the extra links though! =)

[Jens Eklund]

Originally Posted by Ethan Winer

Yes! Though measuring helps to see how bad the room is now, and how much better it got after treatment. But your basic premise is correct, because the solution for most rooms is the same no matter what you measure.

Hm?

Do you not think it’s a good idea to first find out what modes (and other issues) is causing trouble so you know that areas needs attention and what kind?

[btroberts]

Hi Jens,

Thanks for joining in, wouldnt it more or less always be the case that the corners need doing, behind the monitors, the side sweet spot reflections points, and above the mix spot, and you can't over bass trap anyway can you really?

Please, note the above is just what ive picked up over the last week mooching about on here and other places, I'm more than happy to be edjimacated

[btroberts]

Originally Posted by Ethan Winer

Yes! Though measuring helps to see how bad the room is now, and how much better it got after treatment. But your basic premise is correct, because the solution for most rooms is the same no matter what you measure.

--Ethan

________________
The Acoustic Treatment Experts

Thanks for confirming, It just always seems to be the same solution more or less from I have gathered...!

[SAC]

Originally Posted by btroberts

In the end all I can do is Basstrap the room anyway isnt it, and this is always going to be behind the monitors on the reflection points, the corners and the back of the room right? so what use is measuring it given I'lll likely have little option as to what I do?

No. Wrong.

You may limit yourself to doing only this.
But your question is curious as it proceeds to place limitations and restriction on what you can and will do (and what information the measurements may provide) before you take measurements.

Depending upon your desired use and your room, there are many options. And you can either do it properly dependent upon what is actually happening in your room, or you can assume that your room is like every other room and simply follow the generic regimen that treats every room as if it is the same.

I mean, I can provide you with a 3 sentence procedure for establishing just about any acoustical response you desire oriented around some imagined generic room. But if you think that this is all there is to actually achieving the response where the devil is in the details and the specific treatments, you are in for a few surprises.

The next time you go to the dentist or the doctor, challenge them ion why they want xrays or perhaps even an MRI, as the treatment for cavities is all about the same, as are the procedures for an appendectomy or setting a bone or for that matter, removing a rain tumor or performing heart bypass.

You may limit yourself by only installing bass traps (BTW, what kind of bass traps, as they are ALL the same? Right?) And you will simply procedure to cover the side walls and ceiling to minimize first order reflections resulting in a dead room? Right?

Ethan is correct in stating the general pattern which is to install bass traps top control modal decay and even broadband absorption to control specular reflections.

But each room and each treatment type (format, material, incident angle, etc.) varies.

And depending upon what YOUR presumed goals and expectations are, you choose the degree of awareness, and hence the specific options based upon the specific knowledge of the real room behavior as well as the real behavior of each type of treatment.

So, if you ascribe to the self-imposed "All rooms are the same, and I can only do one thing and there are no variations or choices and all results are the same" philosophy, then, yes, your stated assumptions are probably correct given those self-imposed restrictions.

But the fact is, that one type of treatment, while it may be labeled a "bass" trap, may significantly alter other aspects of the acoustical behavior in the space. If only a treatment's behavior were defined by its logical description! Or that absorbers only absorbed and did not reflect! Or that diffusors only diffused and did not exhibit significant diffractive losses...

Nevertheless, simple measurements including waterfalls for modal behavior and ETCs provide insight into the presence, gain, arrival time, and path of each specular reflection, and the ability to individually identify and differentiate constructive and destructive reflections and to surgically treat them and verify the effectiveness of each treatment.

And then YOU get to determine what options are actually available, and just what choices actually exist both in terms of the possible acoustical response goal as well as the specific plan that you might choose to pursue based upon the acoustical response you choose.

Its your choice. You can do it based upon blind assumption, or you can do it based upon detailed information.

Personally, even if I chose not to do anything, it would be preferable to do so based upon a real understanding of what is actually happening and an assessment of the real variables.

And ultimately, the difference is the time it takes to download and operate RoomEQWizard and to buy a general purpose Behringer mic.

But ultimately its your choice.



Oh, and given a choice between the inexpensive Behringer ECM8000 and the RS SPL meter for general room measurements, this choice is simple - DO NOT go with the RS SPL meter! Go with the Behringer mic!!!

You wonder why. when you imagine the RS SPL meter will be so incredibly useful(sic) for so many things (I wish!)? Go go search for the thread on lass of bass response that occurred this week that had us all chasing our tails until we discovered the cause - that the result difference that defined the panic was simply that of a response measured with a decent mic, and the response measured using the RS SPL meter that severely distorted the results.

[btroberts]

Originally Posted by SAC

No. Wrong.

You may limit yourself to doing only this.
But your question is curious as it proceeds to place limitations and restriction on what you can and will do (and what information the measurements may provide) before you take measurements.

Depending upon your desired use and your room, there are many options. And you can either do it properly dependent upon what is actually happening in your room, or you can assume that your room is like every other room and simply follow the generic regimen that treats every room as if it is the same.

I mean, I can provide you with a 3 sentence procedure for establishing just about any acoustical response you desire oriented around some imagined generic room. But if you think that this is all there is to actually achieving the response where the devil is in the details and the specific treatments, you are in for a few surprises.

The next time you go to the dentist or the doctor, challenge them ion why they want xrays or perhaps even an MRI, as the treatment for cavities is all about the same, as are the procedures for an appendectomy or setting a bone or for that matter, removing a rain tumor or performing heart bypass.

You may limit yourself by only installing bass traps (BTW, what kind of bass traps, as they are ALL the same? Right?) And you will simply procedure to cover the side walls and ceiling to minimize first order reflections resulting in a dead room? Right?

Ethan is correct in stating the general pattern which is to install bass traps top control modal decay and even broadband absorption to control specular reflections.

But each room and each treatment type (format, material, incident angle, etc.) varies.

And depending upon what YOUR presumed goals and expectations are, you choose the degree of awareness, and hence the specific options based upon the specific knowledge of the real room behavior as well as the real behavior of each type of treatment.

So, if you ascribe to the self-imposed "All rooms are the same, and I can only do one thing and there are no variations or choices and all results are the same" philosophy, then, yes, your stated assumptions are probably correct given those self-imposed restrictions.

Nevertheless, simple measurements including waterfalls for modal behavior and ETCs provide insight into the presence, gain, arrival time, and path of each specular reflection, and the ability to individually identify and differentiate constructive and destructive reflections and to surgically treat them and verify the effectiveness of each treatment.

And then YOU get to determine what options are actually available, and just what choices actually exist both in terms of the possible acoustical response goal as well as the specific plan that you might choose to pursue based upon the acoustical response you choose.

Its your choice. You can do it based upon blind assumption, or you can do it based upon detailed information.

Personally, even if I chose not to do anything, it would be preferable to do so based upon a real understanding of what is actually happening and an assessment of the real variables.

And ultimately, the difference is the time it takes to download and operate RoomEQWizard and to buy a general purpose Behringer mic.

But ultimately its your choice.



Oh, and given a choice between the inexpensive Behringer ECM8000 and the RS SPL meter for general room measurements, this choice is simple - DO NOT go with the RS SPL meter! Go with the Behringer mic!!!

You wonder why. when you imagine the RS SPL meter will be so incredibly useful(sic) for so many things (I wish!)? Go go search for the thread on lass of bass response that occurred this week that had us all chasing our tails until we discovered the cause - that the result difference that defined the panic was simply that of a response measured with a decent mic, and the response measured using the RS SPL meter that severely distorted the results.

Thanks for your input,

Summing up your post you seem to say

'treating your room without measuring it, is to do a half-assed job which may or may not work well'..

Is that right?

I couldn't actually make the joint worse though could I? by just trying to follow the kind of pattern of say a gik room plan along the lines I suggested? Your DR analogy seems to suggest I could actually cause dire consequences by doing so..? It just seems to me that even people have measured properly etc pretty much end up doing what I said in the end anyway - within the context of a home studio anyway..I can only go off what Ive seen so far, so I can fully accept this may be cobblers should you so suggest..Its not like I have an irrational fear of a measurement mic, I guess I'll get one anyway, but just trying to keeps costs right down at this moment in time and a measurement mic costs a couple of diy panels, hence the question

Thanks

[SAC]

Originally Posted by btroberts

I couldn't actually make the joint worse though could I?

Actually, you can spend money and energy and time and simply move problems around.

That alone in my world is "worse".

And if you end up introducing new or supporting existing destructive reflections, yes, you can make it objectively worse.

Some simply see the world a bit differently and desire a demonstrable improvement as a standard for taking action and considering things to be "better".

But hey, if you want to rationalize mediocrity - based on the foregone conclusion that postulates that the choice is either that it 'won't make much difference' or 'someone will die' - do whatever you like.


Its not surprising to see where the notion in school arises where it doesn't matter if you do something correctly, as everyone who simply participates gets a ribbon. And willful ignore-ance sure is blissful.

[btroberts]

Originally Posted by SAC

Actually, you can spend money and energy and time and simply move problems around.

That alone in my world is "worse".

And if you end up introducing new or supporting existing destructive reflections, yes, you can make it objectively worse.



Look, if you want to rationalize mediocrity - do whatever you like.

I hear cable supports and magic crystals are popular....

Thanks for your kind words, a pleasure interacting with you Im sure. It must be nice being god.

As it happens, I will probably get the measurments done as well as getting in the materials it will be interesting to see how things are an hopefully how they change..Suffice to say I will kindly ask Ethan who isnt a nasty piece of work to help me through.

In the kindest manner possible, please can you refrain from posting further, I actually enjoy talking about this stuff and contrary to your assumptions and pontifications do want to get the best result I can within the context of what I can afford and what skills I may and may not have...
Thanks

[PaulP]

Originally Posted by btroberts

I actually enjoy talking about this stuff and contrary to your assumptions and pontifications do want to get the best result I can within the context of what I can afford and what skills I may and may not have...

You say you want the best result but you refuse to accept that you're going to have to do some work to get there.

[Hannes_F]

Originally Posted by btroberts

Hi,

I am just wondering what the point of measuring a room with say room eq wizard is before embarking on a diy bass trap project..In the end all I can do is Basstrap the room anyway isnt it, and this is always going to be behind the monitors on the reflection points, the corners and the back of the room right? so what use is measuring it given I'lll likely have little option as to what I do?

Please forgive my ignorance, I was going to just pick a project, get the materials in and start building but I thought I'd better check first as I will need to buy a measurement mic if I need to do measurements first.

btroberts,

don't let anybody take the fun away from you. The arguments might be right but if the style is acid and unsupportive ... just ignore.

In responding to your question here is a general idea of what is going on: Your untreated room will probably have a bracket of frequency response (highest point minus lowest point) of 40-50 dB. If you insert panels and bass traps in the way you indicated this will be reduced to around 20-25 dB ... which is clearly better. However if you want to get that down to 15 dB or better, with other words into the 'usable' range, you need to move your speakers, your listening position and your treatment around and that would be the ultimative point where you need measurements.

The other factor to consider is the decay. Beginners focus on the frequency response but the decay is as imporant or even more. The bass can need a little longer than the treble but overall you want the decay times to be quite similar depending on the frequency and not a few to stick out. You can do a lot in that regard by fine positioning (and deciding on) your treatment but again there is little hope to do that without measurements. There is also a high probability that you overdampen your room in order to get the bass response right but in exchange you get too short decay times in the mids and treble.

Finally what you want to watch is how many early reflections still mess up your stereo imaging. You might think you killed all early reflections in the reflection points but how sure are you that you did not use the wrong covering, how can you know whether the size of your early reflection panels is big enough or already too big? So called ETC measurements can tell you that exactly.

So ... what you have in mind works to an amount but you need to fine tune with a mic at the end if you want to have a reliable result. Also you should at least know that there are ways to deal with the acoustics in a different way: You start with an empty room, measure the room and insert treatment where it is needed step by step. I am not saying this is practical for you because it needs advanced acoustical knowledge but it is good to know that such methods exist.

And then there are totally different methods of studio design of course that don't deal with much visible absorption but involve more construction work. They can give better end results in regards to all three topics (frequency response, decay and early reflections) but they are really advanced, so I would skip that if these are your first steps in room treating.

[btroberts]

Originally Posted by PaulP

You say you want the best result but you refuse to accept that you're going to have to do some work to get there.

Hi Paul, read my post again. I dont refuse to do anything. Thanks

[btroberts]

Originally Posted by Hannes_F

btroberts,

don't let anybody take the fun away from you. The arguments might be right but if the style is acid and unsupportive ... just ignore.

In responding to your question here is a general idea of what is going on: Your untreated room will probably have a bracket of frequency response (highest point minus lowest point) of 40-50 dB. If you insert panels and bass traps in the way you indicated this will be reduced to around 20-25 dB ... which is clearly better. However if you want to get that down to 15 dB or better, with other words into the 'usable' range, you need to move your speakers, your listening position and your treatment around and that would be the ultimative point where you need measurements.

The other factor to consider is the decay. Beginners focus on the frequency response but the decay is as imporant or even more. The bass can need a little longer than the treble but overall you want the decay times to be quite similar depending on the frequency and not a few to stick out. You can do a lot in that regard by fine positioning (and deciding on) your treatment but again there is little hope to do that without measurements. There is also a high probability that you overdampen your room in order to get the bass response right but in exchange you get too short decay times in the mids and treble.

Finally what you want to watch is how many early reflections still mess up your stereo imaging. You might think you killed all early reflections in the reflection points but how sure are you that you did not use the wrong covering, how can you know whether the size of your early reflection panels is big enough or already too big? So called ETC measurements can tell you that exactly.

So ... what you have in mind works to an amount but you need to fine tune with a mic at the end if you want to have a reliable result. Also you should at least know that there are ways to deal with the acoustics in a different way: You start with an empty room, measure the room and insert treatment where it is needed step by step. I am not saying this is practical for you because it needs advanced acoustical knowledge but it is good to know that such methods exist.

And then there are totally different methods of studio design of course that don't deal with much visible absorption but involve more construction work. They can give better end results in regards to all three topics (frequency response, decay and early reflections) but they are really advanced, so I would skip that if these are your first steps in room treating.

Thanks for this. thats interesting, so lets say I empty my room out and do measurements, then what? Do I put everything back in and do a measurrements, do it with one item in at a time etc..How do I build up a series of measurments that ultimately results in all my kit being in there positioned in the optimum place with me getting the optimum result from where I am sat?

I will have to skip construction sadly, I already know that one wall could do well to have another put over it, but there are some scribblings and scrawlings over this wall that my landlord wants to retain, due to some pop star living here previosuly and the scribblings being from the time their charted album was made lol, so ultimately it is going to involve purchasing or making visible treatments, but I do want to get it done as best I can..thanks

[localhost127]

Originally Posted by btroberts

Thanks for this. thats interesting, so lets say I empty my room out and do measurements, then what? Do I put everything back in and do a measurrements, do it with one item in at a time etc..How do I build up a series of measurments that ultimately results in all my kit being in there positioned in the optimum place with me getting the optimum result from where I am sat?

the reason 'take measurements first; in empty room' is communicated so often is because it will identify the fundamental issues with your room.

you could do this, and then treat the specific issues directly...or you could blindly install 100traps and hope for the best. waste of money and like sac said above, you could create new problems.

it's generally a good exercise to ttake the scientific approach regarding such matters... or if you don't want to put the effort forth, dont expect great results - that's the one thing ive learned from reading this subforum nonstop for the past 6months

[Hannes_F]

Originally Posted by btroberts

Thanks for this. thats interesting, so lets say I empty my room out and do measurements, then what? Do I put everything back in and do a measurrements, do it with one item in at a time etc..How do I build up a series of measurments that ultimately results in all my kit being in there positioned in the optimum place with me getting the optimum result from where I am sat?

Practically speaking I would say, skip that. It is just important to know that this methodology exists in case you get according advice. Then you say to yourself "ok they are right but I am not there yet".

In order to describe it briefly: You measure the room resonances of your empty space, identify them all one by one and then you insert a mixture of tuned traps and some broadband absorbers ... right at the places where these modes can be caught. Way too complicated for the state you are in. Maybe after you have read several books about acoustics etc. but do you really want to stop making music for two years until you have learned all that?

That is why I suggest you go the standard way of panels plus superchunks etc. BUT flank it with measurements. Do some good music, earn some money, and if you want to have a better room after two or three years you are way better off if you hire a consultant that does all the calculations for you

[DanDan]

bt, most of your questions are answered here
http://www.gearslutz.com/board/studi...er-v2-1-a.html

It's fun when you get into it. FuzzMeasure is the easiest to use but is Pro at heart.

More briefly-

No to RS Meter, trouble. A 58 is better than that.

If you want a quick and sure way to prescribe room treatment try the following.

Calculate your Room Modes.
Carefully sweep sine waves at the first 4-6 lowest modes. Stop on each one and map the locations of nulls and peaks.
Don't forget to examine vertically.

This will deliver tons of information. Where to put bass traps. Where not to sit. Where/not to place speakers and so on.

It is a goal orientated technique. It has the advantage of proving actual locations in the room.

Advice regarding RFZ Cloud stands of course. Beware desk surface reflections. Angle the desk or otherwise minimise it.


DD

[btroberts]

Originally Posted by Hannes_F

Practically speaking I would say, skip that. It is just important to know that this methodology exists in case you get according advice. Then you say to yourself "ok they are right but I am not there yet".

In order to describe it briefly: You measure the room resonances of your empty space, identify them all one by one and then you insert a mixture of tuned traps and some broadband absorbers ... right at the places where these modes can be caught. Way too complicated for the state you are in. Maybe after you have read several books about acoustics etc. but do you really want to stop making music for two years until you have learned all that?

That is why I suggest you go the standard way of panels plus superchunks etc. BUT flank it with measurements. Do some good music, earn some money, and if you want to have a better room after two or three years you are way better off if you hire a consultant that does all the calculations for you

Thanks hannes, what you have said is more or less what I supsected really, but it makes more sense now. I def don't want to spend months and years doing acoustics not at present no, for one I can't afford it. I just need to get a workable room, getting the low end nice is the main thing, as I will be doing electronic stuff. I will take the route you suggest. I will come back with some measurements, a layout of the room etc soon

Much obliged

[btroberts]

Originally Posted by DanDan

bt, most of your questions are answered here
http://www.gearslutz.com/board/studi...er-v2-1-a.html

It's fun when you get into it. FuzzMeasure is the easiest to use but is Pro at heart.

More briefly-

No to RS Meter, trouble. A 58 is better than that.

If you want a quick and sure way to prescribe room treatment try the following.

Calculate your Room Modes.
Carefully sweep sine waves at the first 4-6 lowest modes. Stop on each one and map the locations of nulls and peaks.
Don't forget to examine vertically.

This will deliver tons of information. Where to put bass traps. Where not to sit. Where/not to place speakers and so on.

It is a goal orientated technique. It has the advantage of proving actual locations in the room.

Advice regarding RFZ Cloud stands of course. Beware desk surface reflections. Angle the desk or otherwise minimise it.


DD

Whats a 58? A measurement mic? I was looking to get the behringer..

Will defianately take a look at that primer and probably come back with some questions if thats ok,

Thanks my man

[Ethan Winer]

Originally Posted by btroberts

I couldn't actually make the joint worse though could I?

Not likely. Though it would have helped if you told us the room dimensions. But I'm curious how the "you must measure first" proponents will address this: Attached are four graphs showing the response measured in four different rooms. I'd love to hear what specifically should be done in each room, or at least what would be done differently based on this measurement data.

--Ethan

[btroberts]

Originally Posted by Ethan Winer

Not likely. Though it would have helped if you told us the room dimensions. But I'm curious how the "you must measure first" proponents will address this: Attached are four graphs showing the response measured in four different rooms. I'd love to hear what specifically should be done in each room, or at least what would be done differently based on this measurement data.

--Ethan

Hi ethan, I will definately pop back with some dimensions etc..

[Jens Eklund]

Originally Posted by Ethan Winer

Not likely. Though it would have helped if you told us the room dimensions. But I'm curious how the "you must measure first" proponents will address this: Attached are four graphs showing the response measured in four different rooms. I'd love to hear what specifically should be done in each room, or at least what would be done differently based on this measurement data.

Don’t you agree that if for example a measurement shows only one problematic axial mode, you only need to treat specific area(s) related to this mode (in terms of this particular problem that is)?

I’m getting worried here!

[Ethan Winer]

Originally Posted by Jens Eklund

I’m getting worried here!

LOL.

As for targeting a specific single problem mode, when does that ever happen?

--Ethan

[Jens Eklund]

Originally Posted by Ethan Winer

LOL.

As for targeting a specific single problem mode, when does that ever happen?

--Ethan

[JohnPM]

Originally Posted by Jens Eklund

Attachment 220675

Now that's a mode to be proud of!

[Jens Eklund]

Originally Posted by JohnPM

Now that's a mode to be proud of!

Thank you!

[Hannes_F]

Originally Posted by Jens Eklund

Attachment 220675

BTW what would one do in the case of two modes in the same direction, but not close, for example 50 Hz and 200 Hz? Use tuned traps of the both frequencies besides each other, or behind?