Need help to tune my control room. (First Measures Included)

[Mctwins]

Hallo..

I have seen your measurements and I still don't see any difference compared to before, I don't see the result, namely, peaks hasen't been reduced and the resonaces is still there in the corners. The decay is not improved as well.

Using the boxes instead of broadband absorber is a good thing here, but, if the boxes are not doing what it is supposed to do, then you can be without the boxes as well......or it seems that you need to have plenty of those boxes to be effective, measurement wise.

I don't like when you are moving the mic differently when you are comparing the results from before and after. Don't move the mic.

Do like this, put the mic at listening position (don't move this position) and measure without the boxes and remeasure with the boxes installed. Then compare before and after.

I agree, it is a huge BUMP here.

[Alejandro Varela]

I hear that something had changed. REW's graphics looks better (to me), specialty on C & D corners, A & B corners are difficult, cause my first measures was made at 60 from corner and 1 mt from floor. I couldn't measure at the same mic position cause boxe's edge are 40 cm down to the mic (they are standing at floor now)
Ok, I will make new measures... and test at the same MP!
Thanx for your time!!!

[GIK Acoustics]

Originally Posted by Alejandro Varela

Today I' m gonna build some Bass traps panels for early reflections...
Side panels can be 1 inch, isn't it?

Hey Alejandro,

I would suggest making them at least 2" with a 2" air gap, but would prefer 4" with some air gap if it's possible.

Originally Posted by Mctwins

I don't like when you are moving the mic differently when you are comparing the results from before and after. Don't move the mic.

Do like this, put the mic at listening position (don't move this position) and measure without the boxes and remeasure with the boxes installed. Then compare before and after.

Yes, this would be necessary if you wished to compare the graphs before and after. Different mic positions would render the tests useless when comparing the effect of added bass traps. Alejandro, I'm sure it would be beneficial for those inclined to build those same traps to post your new results in that thread as well so people can know what to expect if they build them as well.

[Mctwins]

Originally Posted by Alejandro Varela

I hear that something had changed. REW's graphics looks better (to me), specialty on C & D corners, A & B corners are difficult, cause my first measures was made at 60 from corner and 1 mt from floor. I couldn't measure at the same mic position cause boxe's edge are 40 cm down to the mic (they are standing at floor now)
Ok, I will make new measures... and test at the same MP!
Thanx for your time!!!

Off course you have heard some change. It is because you don't have the broadband absorber anymore. It has nothing to do with the bass problem.

[Mctwins]

Do you really need that wardrobe???

[Alejandro Varela]

Thank you. Time to measure.

[Alejandro Varela]

Originally Posted by Mctwins

Do you really need that wardrobe???

Well it filled with instruments... gtr, sitars, basses etc. I don't have more place to put that stuff. but my idea is to convert wardrobe doors into QRD or is a crappy idea?

[Mctwins]

Ok, I see. Lots of distortion in there.

Don't forget the x-mas celebration.

[Alejandro Varela]

Originally Posted by Mctwins

Ok, I see. Lots of distortion in there.

Don't forget the x-mas celebration.

...but if my wardrobe is crucial, I could get out there...

Ok , new measurements made.
It seems that everything 's the same. Grrrrrrr!!!!
Maybe my boxes aren't well build?
Maybe I should build more...
Maybe I should trash boxes and test with superchunks!

The mic wasn't move this time...

NW8 before 2.zip

NW8 after 2.zip

Happy X-mas!!!

[Mctwins]

Originally Posted by Alejandro Varela

...but if my wardrobe is crucial, I could get out there...

Ok , new measurements made.
It seems that everything 's the same. Grrrrrrr!!!!
Maybe my boxes aren't well build?
Maybe I should build more...
Maybe I should trash boxes and test with superchunks!

The mic wasn't move this time...

Attachment 322172

Attachment 322173

Happy X-mas!!!

Now you see the importance of having the mic in the same position. You are right, it is the same. I really don't see the changes at all.

I have been in the same situation when I build something like those boxes and finding out it is not working, spending the time with labour work and so on.....is very frustrating. It is very difficult to predict what the target freq one schould aim for. Maybe you schould build more, different sizes, different membrane material. Only you can make this decision.

If I where you, I would leave it as it is. No broadband absorbtion, no boxes and start mixing. The result is the same.

[Alejandro Varela]

Originally Posted by Mctwins

Now you see the importance of having the mic in the same position. You are right, it is the same. I really don't see the changes at all.

I have been in the same situation when I build something like those boxes and finding out it is not working, spending the time with labour work and so on.....is very frustrating. It is very difficult to predict what the target freq one schould aim for. Maybe you schould build more, different sizes, different membrane material. Only you can make this decision.

If I where you, I would leave it as it is. No broadband absorbtion, no boxes and start mixing. The result is the same.

What is this for?
I came to Gearslutz not to leave the things as it is.... I trust in people in this forum.
I made all suggestion you told me. I' m not on a good economical situation and waste my last bucks and efforts on something that doesn't works to hear
things like "don't worry m8... leave it as it is". Scam!!!!!!!!

[Mctwins]

Originally Posted by Alejandro Varela

What is this for?
I came to Gearslutz not to leave the things as it is.... I trust in people in this forum.
I made all suggestion you told me. I' m not on a good economical situation and waste my last bucks and efforts on something that doesn't works to hear
things like "don't worry m8... leave it as it is". Scam!!!!!!!!

Calm down....
I haven't suggesting anything to you. I didn't say to you to build those boxes.

What kind of treatmnet you are building is still up to you, I am only commenting about the measurements.

[Alejandro Varela]

Originally Posted by Mctwins

Calm down....
I haven't suggesting anything to you. I didn't say to you to build those boxes.

What kind of treatmnet you are building is still up to you, I am only commenting about the measurements.

Yes, but I don't liked to heard that "leave it as it is". You could been more hopeful and suggest "try this" or "made this"...

[Mctwins]

Originally Posted by Alejandro Varela

Yes, but I don't liked to heard that "leave it as it is". You could been more hopeful and suggest "try this" or "made this"...

Ok, I understand.
What I ment about "leave it as it is" is this. If you don't see any changes in the freq response and waterfallplot despite the treatment you are choosing or installing then it is better to leave it untreated.

I tell you what I know, it is very difficult to treat the first modal axiell resonaces with porus absorber, broadband absorber, membrene boxes because these are inefficient below 100Hz, period. Specially small rooms like yours.

Sorry, but, I am not allowed to tell you, "try this" or "made this" in this forum.

[Alejandro Varela]

Originally Posted by Mctwins

Sorry, but, I am not allowed to tell you, "try this" or "made this" in this forum.

I see it
What are you "allowed" to say?

[Mctwins]

Originally Posted by Alejandro Varela

I see it
What are you "allowed" to say?

Good question, I really don't know.

But what I do know is this, if I give you some suggetion about how to deal with your bass problem it seems that some people in this forum get offended.

I have a solution to your bass problems and you will get the result I am looking for.

I am suprized that the people who has answer your question in your thread seems to be vanished, nobody is commenting about your measurements and the suggetion given seems not to be working for you, so far.

Sorry, I have nothing more to add for the moment.

[Alejandro Varela]

Originally Posted by Mctwins

I am suprized that the people who has answer your question in your thread seems to be vanished, nobody is commenting about your measurements and the suggetion given seems not to be working for you, so far.

.

Me too.

[Glenn Kuras]

Not sure why you went down the tuned route but I still contend that THICK broad band in the corners would be a better choice. If you are worried about losing some of the upper frequencies then use a slat design in front of them to help scatter/retain them.
Tuned Trapping is great but if not built right and placed right then it will not work.
GIK or Realtraps?

[Alejandro Varela]

Originally Posted by Glenn Kuras

Not sure why you went down the tuned route but I still contend that THICK broad band in the corners would be a better choice. If you are worried about losing some of the upper frequencies then use a slat design in front of them to help scatter/retain them.
Tuned Trapping is great but if not built right and placed right then it will not work.
GIK or Realtraps?

I' m not went down yet....
I asked several times how to build it and nobody answered me exactly.
REW measures shows i.e. 36.6 hz as the first peak in A corner, so I built a Box with that freq according to Tim's Limp Mass Bass Absorbers equation.
(600/36.6)² / 5 kg/m= 53.74 cm deep x 60 x 40 x 1,8 plywood thickness
2" thick of rockwool on back side.
2 frames to situate rubber on the opposite side which is 15 mm from edge.
Like this pic
http://www.gearslutz.com/board/attac...l_absorber.jpg
Everything was airtight

Regards

[Alejandro Varela]

I will prefer to read about my room specs than to see users betraying.

[Tim Farrant]

Running your room dimensions thru the room mode calculator, there is not a 36Hz mode, so I do not know why you chose that frequency. You do have problems at about 55Hz and 90Hz. I would build traps tuned to these freqs and mount them up in the 4 wall/wall/ceiling corners as I have shown. I think you will get better results. Your room is very cubic so it is going to be difficult to get smooth in the low end.

Tim.

[Adhoc]

I suppose the green front is the rubber(?).

In your pictures one can not see how the rubber was fixed to the frame. Did you use silicone or something like it, in one continous length (= no gaps) between the frame and the rubber and then staple it down with something like 25 mm between the staples? If it is simply fixed to the inner frame with a few nails or so, it is quite probable it is not air proof. The front frame does not apply much of a sealing force at all with only 4 screws out in the corners. (My profession is within sealings and gaskets and it is quite often people think a centre to centre of say 250 mm with M10 screws versus 12 mm thick steel bars with rubber in between is enough to get a good seal. Well often it is not ... and you have wood 25x25 mm or so)

What you could do is to check at about which frequency the boxes do work. Put the boxes at the floor in the corner with your stiffest wall around. If you start with a low frequency and slowly raises it, at some point you should get a "good vibration" from the membrane (if the box is air tight). If it is above your problem frequency, the membrane is to light / m² versus the air spring inside the box. The membrane weight can be increased with some double adhesive tape + some suitable sheet, leave some 5 cm of rubber towards the edges to keep the rubbers good flexibilty.

[Alejandro Varela]

Originally Posted by Tim Farrant

Running your room dimensions thru the room mode calculator, there is not a 36Hz mode, so I do not know why you chose that frequency. You do have problems at about 55Hz and 90Hz. I would build traps tuned to these freqs and mount them up in the 4 wall/wall/ceiling corners as I have shown. I think you will get better results. Your room is very cubic so it is going to be difficult to get smooth in the low end.

Tim.

Really? WOW!!! Why about 55 HZ?
No problem. I can cut plywood edges at back side and put back side again. And have a 23.80 cm deep Box and voilá! A 55 Hz box is made.

Originally Posted by Adhoc

I suppose the green front is the rubber(?).

In your pictures one can not see how the rubber was fixed to the frame. Did you use silicone or something like it, in one continous length (= no gaps) between the frame and the rubber and then staple it down with something like 25 mm between the staples? If it is simply fixed to the inner frame with a few nails or so, it is quite probable it is not air proof. The front frame does not apply much of a sealing force at all with only 4 screws out in the corners. (My profession is within sealings and gaskets and it is quite often people think a centre to centre of say 250 mm with M10 screws versus 12 mm thick steel bars with rubber in between is enough to get a good seal. Well often it is not ... and you have wood 25x25 mm or so)

What you could do is to check at about which frequency the boxes do work. Put the boxes at the floor in the corner with your stiffest wall around. If you start with a low frequency and slowly raises it, at some point you should get a "good vibration" from the membrane (if the box is air tight). If it is above your problem frequency, the membrane is to light / m² versus the air spring inside the box. The membrane weight can be increased with some double adhesive tape + some suitable sheet, leave some 5 cm of rubber towards the edges to keep the rubbers good flexibilty.

Membrane is inserted to the edges with contact cement in all of it's perimeter. Now when I play music if I bring close the palm of my hand I can feel it vibrating...isn't ok?
Anyway I will fill it again with silicone from back side.
Membrane is too fragile to manipulate and I had to trash some piece cause it was perforated on handle. It seems like some paraffin texture.

[Adhoc]

The vibration is a sign that acoustical energy is transformed to heat, that is what the membrane is for, -bring down the energy (amplitude) of a certain frequency by energy transformation. But, at what frequency / range, does this happen with what you built? Play a sine and slowly raise it (instead of music) then you may get a fairly good indication by just observing / touching the membrane.

Is the membrane really rubber weighing in at 5 kg/m²? I mean solid 3-4 mm rubber should not be fragile to handle.

[Alejandro Varela]

Originally Posted by Adhoc

The vibration is a sign that acoustical energy is transformed to heat, that is what the membrane is for, -bring down the energy (amplitude) of a certain frequency by energy transformation. But, at what frequency / range, does this happen with what you built? Play a sine and slowly raise it (instead of music) then you may get a fairly good indication by just observing / touching the membrane.

Is the membrane really rubber weighing in at 5 kg/m²? I mean solid 3-4 mm rubber should not be fragile to handle.

Thank you.
Here' s pic

Tomorrow I'll make the test and cut my boxes to 55 hz as Tim Farrant said and put them at tree!!!

[Alejandro Varela]

Originally Posted by Tim Farrant

You do have problems at about 55Hz and 90Hz. I would build traps tuned to these freqs and ...
Tim.

Originally Posted by Alejandro Varela

Why about 55 HZ?
No problem. I can cut plywood edges at back side ...

Just a dude about freq treatment. Maybe is an stupid question....

Don't you think these freq will be more accurate? I don't wanna make more mistakes and spend my life building boxes...
A Corner
B Corner
C Corner
D Corner

[Mctwins]

Hallo..
It is very difficult to predict which freq one schold tune when looking at those room mode calculators. It is only a guide.

Looking at corner A's waterfall plot you have a resonace at around 35Hz, and a non resonace at 55Hz but a peak instead.

On corner B, there is two resonances and a small peak at 35Hz and a resonance at 50Hz and a larger peak.

I don't see this in the room mode calculation graphs.

Which one schould one choose to build and tune those boxes at??

Don't ask me, it's to way difficult to predict.

[Alejandro Varela]

Originally Posted by Mctwins

Hallo..
It is very difficult to predict which freq one schold tune when looking at those room mode calculators. It is only a guide.

Looking at corner A's waterfall plot you have a resonace at around 35Hz, and a non resonace at 55Hz but a peak instead.

On corner B, there is two resonances and a small peak at 35Hz and a resonance at 50Hz and a larger peak.

I don't see this in the room mode calculation graphs.

Which one schould one choose to build and tune those boxes at??

Don't ask me, it's to way difficult to predict.

I don't realize what you're talking about...
Now, I' m more confused what to do!!!

[Mctwins]

Hi
I am looking at post 99 waterfalls graphs. Your last measurements.

In those measurements, did you measuring with both speakers including the sub?

You can do like this, put the speaker and sub at left corner(floor) and measure on the opposite corner(diagonally), inside wardrobe's upper corner. You can only use sub for this operation as well.

Here you will see all the modes this room have.

[Alejandro Varela]

Originally Posted by Mctwins

Hi
...did you measuring with both speakers including the sub?

You can do like this, put the speaker and sub at left corner(floor) and measure on the opposite corner(diagonally), inside wardrobe's upper corner. You can only use sub for this operation as well.

Here you will see all the modes this room have.

Yes I measured with both speakers and sub.
Thanx. I will do it.