timogiodeson MEASUREMENTS THREADS! Tracking Room Acoustic

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Pink = untreated. red= 4 lenrds in each corner green= 4 lenrd plus 8 pound 4 inc mineral wool

This is great information, Gab. I'd like to provide a quick technical perspective on this. For the sake of brevity, I'm going to focus on two of your modal problems, at 47 and 55-58 Hz. This type of analysis can be repeated on your own with any of the other modes that are resonating ("ringing"). The mode calculator I used was Bob Golds'. Looking at your waterfall graphs, I was able to eyeball the following modal decay times (given as "traditional" T60's): Untreated Room (pinkish waterfall) 47 Hz = ~1.6 s 55-58 Hz = ~1.6 s LENRDs (red waterfall) 47 Hz = ~1.5 s 55-58 Hz = ~1.5 s This is not unexpected since LENRDs alone do not address problems below ~60-80 Hz very well, relatively speaking. LENRDs + 8 lb Mineral Fiber (greenish waterfall) 47 Hz = ~1.1 s 55-58 Hz = ~0.8 s This is a significant improvement and the audible result should be that of having much "tighter" bass, particularly for something like the kick drum. What's your take on how it sounds, Gab? Things getting better? Like/don't like? Please share! :D

lovecow wrote:

LENRDs + 8 lb Mineral Fiber (greenish waterfall) 47 Hz = ~1.1 s 55-58 Hz = ~0.8 s This is a significant improvement and the audible result should be that of having much "tighter" bass, particularly for something like the kick drum. What's your take on how it sounds, Gab? Things getting better? Like/don't like? Please share! :D

thanks for the energy Jeff, last night was too late for playing drums (axially morning 4.00 am) so I had to wait until now.. Yes, sound tighter, I can hear the difference with the drums, mostly on the snare some how... on piano ...the difference is less evident. Getting better? Guess so. Like, don't like? To early to say for me, I don't know where we are going...I never been there where it sound good or I like it yet, so... I don't know really. For sure what I like is to play in a tight, dry, much bigger space with less walls near and around me. can we simulate that some how? Thank you very much for the calculation you did for me, that's very important ! I never thought this room can have a low frequency decay so long .. 1.6s . So... Basically, there is still a lot to absorb to get to the recommended 0.5 -0.7s.. ? also... For a tracking room this size , the goal will be a uniform decay across all the frequencies ? Or perhaps some kind of curve /EQ/ NON flat response that enhance the sound of the acoustic instruments ? What's next? Are we ready for step 2 studio foam ? P.S. Glenn, Aloha and Msikio, with all my respect. thank you very much for your help, time, and the great ideas, I just give myself one more chance with this, if I can get where I need faster with the stuff that I already have in the storage and without additional construction work, I don't mind to try! why not? regards

Gab, If what you're looking for is a "bigger room" sound, then you probably want to go with diffusers next. And you might want to use some of them on the walls in lieu of the absorbers I suggested. Use two of the 2'x6's over each instrument, and use the rest of the diffusers spread out around the four walls, much like I described for the foam. Do that, listen to the room, and let us know what you think! :) All the best,

lovecow wrote:

Gab, If what you're looking for is a "bigger room" sound, then you probably want to go with diffusers next. And you might want to use some of them on the walls in lieu of the absorbers I suggested. Use two of the 2'x6's over each instrument, and use the rest of the diffusers spread out around the four walls, much like I described for the foam. Do that, listen to the room, and let us know what you think! :) All the best,

OK /I will add some diffusers over the instruments and few more starting from the center of the two short walls where long flutter echos.. but...what about bass trapping? I'm done with that for now? I still have, (4) Auralex Lenrds (36) 2x2x2" Aualex studio foam (1) 4x6x4" 2.5 pound mineral wool / fabric wood frame absorber. one box of ceiling tiles 40 square feet of R13 insulation 3 1/2 tick (2) 2x4x2" or (1) 2x4x4" 8 pound FSK mineral wool absorbers about 50 square feet of 2 pound density 3" and 4" tick solid foam. (3) moving blankets (10) about 2x3 poster boards (4) 4x8 1/8 Luann plywood, (10) about 2x3 1/8 tick Masonite. many 2x1 wood furring strips about 10, 2x4 studs and some more plywood. In the main time... I will add some diffusers more later thank you in advance.

Gab, A few thoughts on that: 1. I did not address your "linear T60" inquiry above. To that end, I do not subscribe to this school of thought. A small rise in low frequency T60 relative to the high end is, IMO, better than "flat" in terms of time response, especially taking into consideration your desire for a "bigger sounding" room. (Others here may have different opinions, and you should absolutely hear them out. :) ) So, since the high frequency T60's are initially lower (according to your graphs) and the low frequency treatments will naturally bring down to the high frequency T60's as well (also evident from your graphs), you should be headed in the right direction. 2. You should note that the type of diffusers you are using will affect the low frequencies. They are probably more band-limited, but they will have some effect. 3. If you would like additional control at the low frequencies (after adding diffusion), you could start trapping the wall/ceiling and/or wall/floor corners similar to the wall/wall corners. However, I would hold off on that (but leave room for it!) until you know you want it, mainly because it will be more difficult to do, at least for the wall/ceiling corners. Some would say (I no longer do) that you cannot have "too much" when it comes to "bass traps." This might be true in your room, but considering the type of sound you are looking for, I think the diffusion as a next step will get you pointed in that direction better. 4. Bass may not be the only problem with the piano sound. Piano notes are rich in harmonics. Therefore, cleaning up the mids/highs with diffusion might provide a marked improvement, even for lower notes. Also, I wouldn't rule out some wall absorption - there's a chance some might be necessary. Finally, keep in mind that diffusion as the next step is my suggestion based on your desire to have a "big" - and, presumably, "lively" - room. The next step might be removing or covering some more of the ceiling tiles. My preference would be to cover them with more diffusers. Ultimately, you could wind up with 50% diffusion on the ceiling, somewhere around 20-30% on the walls along with a few absorbers, and - maybe - a few more traps. HTH. Best regards,

lovecow wrote:

Gab, A few thoughts on that:.................................................................................. ,

thanks Jeff! Done ! here some pictures and measurements I didn't place anything permanently.. so I'm not worry about how it looks.... my first impressions... (but I need more playing to really understand) It sound just like if (In my home receiver) I turn: treble- up, Surround -On, loud -On, and then I add just a little bass to be happy .... all this inside an empty room with hard floor basically... the diffusers bring back high frequencies in the room, because of that the bass drum sound less booming more tight with more attack and a little Sub woofer effect... not sure about the surround effect jet... :shock: cymbals and bass drum definitely better, snare , tom toms and also grand piano need more intelligibility presence., probably the mid frequency decay is too long or I'm not sure really what it is.. I guess I like a big but dry warehouse...big and dry. Now my room is bigger! .. just need some treatment I guess .. :) this is only my first impression, I need more listening , I hope this make sense... Also I have a couple questions about the cylindrical diffusers I made.. regards --------------------------------------------------------------------------------- P.S. Room dimensions 19.4 x 12.1 x 8.5 to 8.8 floor 100% coverage vinyl on concrete, ceiling 100% coverage 234 square feet, ceiling tile (approx 1" tick), glue up mount to drywall, all sealed and painted 3 times. walls: drywall Acoustic treatment: 1) floor to ceiling Lenrds behind 8 pounds 4" mineral wool in all 4 corners , 64 Square feet. 2) 10- 2'x6'x6" cylindrical diffusers on the 4 walls, 120 square feet 3) 12- 2'x2'x6" cylindrical diffusers on the ceiling 48 square feet. 4) additional 2- 2x2 Auralex diffuser and 3- 2x2 cylindrical diffusers on the walls. 20 square feet 4) additional 10, poster board on the ceiling approx 40 square feet.

...

And here all the measurements

Impulse response and low frequency decay

two more 1/3 octave smoothing graphics from previous measurements of the untreated room.

B.D.R. wrote:

cymbals and bass drum definitely better, snare , tom toms and also grand piano need more intelligibility presence., probably the mid frequency decay is too long or I'm not sure really what it is..

I think you might be ready to just "tweak" the room. From the above comment, I would guess that you probably need to swap out some wall diffusers for some absorption. How much is up to you and your ears. (I think we're beyond the point of measurements helping us evaluate this space. It's really coming down to you and your preferences.) I would suggest you use 2" panels with 2" airspace behind, or solid 4" materials, or some combination thereof. Which ones and exactly how much is up to you. Foam tends to shave off more of the very high frequencies (> 6-8 kHz), making the room relatively "darker." Fabric-wrapped fiber will reflect relatively more energy up high, which is probably what you want. This will be a step by step process. Remove a diffuser or two; replace with absorption; evaluate. Repeat until happy. And remember that "perfection" is not going to be attainable. Your desire is for a large-room sound. Your reality is a small room. Compromises are going to be inevitable. :wink: Happy treating,

Gab, thanks a lot for sharing the pictures and measurements. I think Jeff is right about adding more mid absorption but you might prefer building John Sayers style slat absorber panels as it don't kills the trebles as much as foam or fabric covered mineral panels. It would be interesting to see the waterfall with a 600ms time range, but it looks like there is still too much ringing in your room, especially in the bass register ?

msikio wrote:

Gab, thanks a lot for sharing the pictures and measurements. I think Jeff is right about adding more mid absorption but you might prefer building John Sayers style slat absorber panels as it don't kills the trebles as much as foam or fabric covered mineral panels. It would be interesting to see the waterfall with a 600ms time range, but it looks like there is still too much ringing in your room, especially in the bass register ?

thanks misikio, I'm writhing some questions for Jeff and yes I do want to try john slat but I don't know how to tune them and how many etc I'm building a corner poly in the main time and I'm curious to measure an hanging damped corner wood panel too if I have chance! the ringing you mean the surround effect :shock: ? I guess need some absorption now.. will see regards

lovecow wrote:

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I think you might be ready to just "tweak" the room. From the above comment, I would guess that you probably need to swap out some wall diffusers for some absorption. How much is up to you and your ears. (I think we're beyond the point of measurements helping us evaluate this space. It's really coming down to you and your preferences.) I would suggest ....... Happy treating,

Thanks Jeff, please, before you leave me alone for ever..:) I never understood "you said...beyond the point of measurements" the point... Too much high frequencies absorption on the ceiling? I don't know how to interpret the measurements jet I just started measuring two weeks ago. For me...I guess, in real life will be better measuring the tracking room with a completely different approach, recording the instruments and evaluate how they sound on tape with the different approaches... I would like ask few questions because like usually I'm getting confused 1) In a small tacking room like this and the instruments I record, I really have the luxury of deciding how I want it to sound ? Or in real life there is only one way to go? 2) This is another very confusing point for me...Diffusion, even in my own post there is different opinions ! Diffusion over a drum set or piano etc.. in a room with 8 or 9' ceiling will comb filtering ? the mic will be only 2 feet from the diffuser if overhead. 3) If it is true that room modes, standing waves etc are the main problem in a small room, how can these problems be resolved using only a minimum amount of bass trapping? for example see the great A. Rominator live or studio kit that include only 8 - 12 Lenrd for my room dimensions? 4) , I have a few questions about my home made diffusers the dimension of this diffusers are 2x2 and 2x6 and about 5-6 inc deep. For a small room like this will be better 3 or 4 inc deep a more low profile? Also will be better to convert all the 2x6 in 2x2 and spread the 2x2 in the walls and ceiling varying the axis? , finally I need to fill inside with insulation ? the sound traveling inside the diffuser will color the sound in the room otherwise? "If I talk inside the cavity especially on the 2x6 I can axially hear that "...?? last, 2 feet wide it's a good cylinder dimension for my room or they should be all different ? 5) if I decide to use only porous absorbers for a more dead but tight dry sound, I will probably use only very tick at least 6 inc deep absorbers and not to many.. do you think in this way I will be able to obtain a uniform decay between the high mid and and low? The high frequencies absorption it's already pushed to the limit right now and there is no room for more? I'm not sure how to interpret the measurements jet , how long is the decay at high frequencies in my room? less , more than about 0.5? 6) my last question some peoples suggest a cloud on the ceiling leaving the edge of the ceiling untreated some other 100% coverage, some other diffusion on the center and absorption toward the edges some suggest diffusion on the upper level of the walls some in the center of the walls , some suggest diffusion away from instruments some suggest diffusion over instruments..etc my logic telling me , bass trapping in the corners, absorption toward the edge and diffusion in the center wall or ceiling...and avoid diffusion close to a mic... what do you think? finally do you think 33 % reflection 33% diffusion, 33% absorption will be a good formula for my room ? sorry for the long reply I'm asking my self all this questions and I tough this is a good opportunity to learn and also to share with other people like me that maybe have similar question. Of course I would like to try the corner Poly and slat resonator approach suggested by Alhoa and Glenn, I'm building a Poly just to experiment a little with it and I will post the measurements , but I don't know how to build and tune the broadband slat resonator for my room, also I don't know how many I need and also I don't know how to interpret the measurements and figure this out. hopefully Glenn or Aloha will post some instructions for me. thank you in advance And sorry for the long replay. regards

Gab,

B.D.R. wrote:

I never understood "you said...beyond the point of measurements" the point...

"Analysis paralysis." At some point, the measurements won't be useful - to us - anymore... ...because we have nothing to correlate the measurement to... ...we are not in the room with you. At that point, you're going to have to rely on what you're hearing. You have to trust your own judgment on these things first and foremost.

1) In a small tacking room like this and the instruments I record, I really have the luxury of deciding how I want it to sound ? Or in real life there is only one way to go?

You always have that option. You have myriad options, in fact. We're just working on the room options here. You might keep in mind that you can always change the room to suit the recording you want.

2) This is another very confusing point for me...Diffusion, even in my own post there is different opinions ! Diffusion over a drum set or piano etc.. in a room with 8 or 9' ceiling will comb filtering ? the mic will be only 2 feet from the diffuser if overhead.

I'm not sure this will matter. No matter what the treatments in the room are, there are going to be good spots and bad spots for instrument mics. However, I can almost guarantee that there will be more good spots with diffusion than without.

3) If it is true that room modes, standing waves etc are the main problem in a small room, how can these problems be resolved using only a minimum amount of bass trapping? for example see the great A. Rominator live or studio kit that include only 8 - 12 Lenrd for my room dimensions?

Well, like I said earlier, if you think the room needs more "bass traps," then go for it! I don't think it will hurt.

4) If I decide to use my home made cilyndrical diffusers, I have a few questions about. the dimension of this diffusers are 2x2 and 2x6 and about 5-6 inc deep. For a small room like this will be better 3 or 4 inc deep a more low profile?

The deepest you can go without bumping your head, IMO. ;)

Also will be better to convert all the 2x6 in 2x2 and spread this in the walls and ceiling in different directions or the 2x6 vertical in strip alternating with some absorption are just fine?

I don't understand this question. Perhaps you could phrase it better?

finally I need to fill inside with insulation ? the sound traveling inside the diffuser will color the sound of the room otherwise? "If I talk inside the cavity especially on the 2x6 I can axially hear that "...??

Filling them with insulation would be a good thing - do that before you add anymore "bass traps," btw.

last, 2 feet wide it's a good cylinder dimension for my room or they should be all different ?

Yes. :) Two feet is a good dimension and they can all be different. If you fill them with insulation, they do not need to be different. But they can be if you prefer.

5) if I decide to use only porous absorbers for a more dead but tight dry sound, I will probably use only very tick at least 6 inc deep absorbers and not to many.. do you think in this way I will be able to obtain a uniform decay between the high mid and and low? or the high frequencies absorption it's already pushed to the limit right now and there is no room for more? I'm not sure how to interpret the measurements jet , how long is the decay at high frequencies in my room? less , more than about 0.5?

The HF decay is harder to estimate from waterfall plots. Can your program calculate T60 directly? If not, can you filter the impulse graphs at different octave or 1/3-octave bands? To answer your question, I think you would need a lot more absorption to get close to "too much." Right now, you've only got some "traps" and some ceiling tiles for absorption. As long as the total coverage of absorption doesn't creep to much above 25% (walls and ceiling), things should stay "even." ;)

6) my last question some peoples suggest a cloud on the ceiling leaving the edge of the ceiling untreated some other 100% coverage, some other diffusion on the center and absorption toward the edges some peoples suggest diffusion on the upper level of the walls some in the center of the walls etc..some suggest diffusion away from instruments some suggest diffusion over instruments..etc my logic telling me , bass trapping on the corners, absorption toward the edge and diffusion in the center wall or ceiling...and avoid diffusion close to a mic... what do you think?

You might hate this answer, but I think those are all valid points. I think I have been in rooms that have been treated each way you described. They all had their advantages and disadvantages. If you want to keep the diffusion towards the middle of the room - and avoid mic positions - that's fine. But there are no "rules" about it. If you want to keep the diffusion areas over the instruments (which is what I prefer) and not worry about where the mics go, that can work, too. It might also be worth noting that you may never be "finished" treating the room. Adjusting the treatments and, therefore, the sound of a recording room is not uncommon, especially when it's relatively small.

finally do you think 33 % reflection 33% diffusion, 33% absorption will be a good formula for a room ?

There is no one combination that's going to be good for "a room." A 1:1:1 ratio might work for your room, but it won't work for everyone.

sorry for the long reply I'm asking my self all this questions and I tough this is a good opportunity to learn and also to share with other people like me that maybe have similar question.

No problem. I'm sorry if my answers aren't usually "yes" or "no." :?

Of course I would like to try the corner Poly and slat resonator approach suggested by Alhoa and Glenn, I'm building a Poly just to experiment a little with it and I will post the measurements , but I don't know how to build and tune the broadband slat resonator for my room, also I don't know how many I need and also I don't know how to interpret the measurements and figure this out. hopefully Gleen or Aloha will post some instructions for me.

Either of them - or John - should be able to help you with the slat absorber design.

thank you for answering to all my questions Jeff.

lovecow wrote:

I don't understand this question. Perhaps you could phrase it better?

hopefully :)... OK, on the walls, will be better to use 2'x2' diffusers varying the axis/position of each diffuser instead using the big 2'x6' cylinders (on my pictures) almost floor to ceiling without varying the axis? I can cut and convert each 2x6 in (3)2x2 eventually...

lovecow wrote:

The HF decay is harder to estimate from waterfall plots. Can your program calculate T60 directly? If not, can you filter the impulse graphs at different octave or 1/3-octave bands?

I don't know how to program calculate the T60 yet.. but I did provided various 1/3-octave graphics on my previous replay to you, " look for the graphics named 1.3 octave smoothing"

If you want to keep the diffusion towards the middle of the room - and avoid mic positions - that's fine. But there are no "rules" about it. If you want to keep the diffusion areas over the instruments (which is what I prefer) and not worry about where the mics go, that can work, too

Well if there is not to worry about comb filtering and is not mandatory to use absorption in the walls and ceiling around the mic , I will use just what I like and stop worrying about. thanks again. regards

You can get a RT60 measurement with the demo version of ETF The slat resonators are described here : [url=http://www.johnlsayers.com/HR/index1.htm ][/url]

B.D.R. wrote:

lovecow wrote:

I don't understand this question. Perhaps you could phrase it better?

hopefully :)... OK, on the walls, will be better to use 2'x2' diffusers varying the axis/position of each diffuser instead using the big 2'x6' cylinders (on my pictures) almost floor to ceiling without varying the axis? I can cut and convert each 2x6 in (3)2x2 eventually...

It wouldn't appear to me that this will make much difference. Could be a good thing since it will give you more versatility.

I don't know how to program calculate the T60 yet.. but I did provided various 1/3-octave graphics on my previous replay to you, " look for the graphics named 1.3 octave smoothing"

I did see that and it's useful, at least for the FR graphs. If you want HF T60, though, you're probably going to have to figure out filtering the impulse response or, as msikio pointed out, ETF has a module that will calculate it automatically.

Well if there is not to worry about comb filtering and is not mandatory to use absorption in the walls and ceiling around the mic , I will use just what I like and stop worrying about.

Well, comb-filtering should not be "ignored," per se - I didn't mean to imply that. But, I feel it's probably going to be a moot issue if, as you have surmised, you're using what you like. Then, indeed, there will be little to worry about! ;) All the best,

msikio wrote:

You can get a RT60 measurement with the demo version of ETF The slat resonators are described here : [url=http://www.johnlsayers.com/HR/index1.htm ][/url]

thanks misikio, I'm using the room eq wizard suggested by Gulfo right now, I hope there is a way/ option to calculate the RT60 with the program I already have.. About the slat resonator, I started measuring the room because the broadband slat resonators need to be tuned based on the room " Gulfo told me" here:

gullfo wrote:

B.D.R. wrote:

1) what size and coverage of angled broadband slot resonator I need for this room? just few small slots in each wall just like 2x4 panels? or all around the rom making angles? floor to ceiling?

it depends on the room modes. we can estimate based on the size what frequencies are most problematic, or you could measure the room (using Room EQ wizard or ETF for example) and we could determine what treatments you need - mode control, RT60, etc..

B.D.R. wrote:

2) " broadband " what slot size /thickness and space between slots for the broadband?

see #1

B.D.R. wrote:

3) Polys, how many and what size poly for this room?

in this case, you might construct polys across each corner of the room to add diffusion and broadband bass trapping. straddle the corners with the poly. leave the back of it open and line with insulation. seal the top and bottom. if you can go floor-ceiling, even better.

Also Alhoa suggested broadband angled slat resonators here:

kendale wrote:

Aloha,

B.D.R. wrote:

and what kind of acoustic treatment you suggest for the walls/ceiling around the piano and drum and bass corners?

I would start with 2' x 4' x 4" thick panels of 2.5 pcf mineral wool in all four corners - floor to ceiling. Next, try to break up the parallel wall surfaces with angled slat broadband absorbers. Finally, I would add several cloud absorbers (3"-4" thick mineral wool @ 2.5 pcf) over the drums & bass. Depending on how close you are miking the piano, you may be okay there. If there's too much bleed in the piano mics, perhaps a couple of gobos or the moving blankets will help. In a room this size, I would not use diffusion, especially around areas that are close to the mics due to comb filtering. I think you will find in this forum the majority of acoustic treatments calling for 3"-4" of fiberglass/rock wool/mineral wool @ 2.5-3 pcf instead of the typical foam products available. Hope this helps, Aloha 8)

So.. yes I would like to build this slat resonators but it's not really easy without help, I don't know how many I need , how big they need to be, and how to tune them for my room. I provided the measurements requested , that was the main point for measuring the room ... At the same time thanks to the measurements, I had chance to see how the acosutical material I have works in my room.. So I'm waiting for Glenn, Kendale or John replay. thanks

the slats John has on his wall unit page are generally meant for mid-high absorption depending on how much slat-slot spacing you use. there are a number of Helmholtz calculators floating around, some on this very site... you could build a couple of these units and put them on the walls between instruments to break up some of the echos. you could also use 2" rigid insulation absorber panels staggered around the walls and ceiling to also break things up and absorber mid-high as well...

gullfo wrote:

the slats John has on his wall unit page are generally meant for mid-high absorption depending on how much slat-slot spacing you use. there are a number of Helmholtz calculators floating around, some on this very site... you could build a couple of these units and put them on the walls between instruments to break up some of the echos. you could also use 2" rigid insulation absorber panels staggered around the walls and ceiling to also break things up and absorber mid-high as well...

Ok Glenn thanks but, :? I made all this measurements because you said...:

gullfo wrote:

B.D.R. wrote:

1) what size and coverage of angled broadband slot resonator I need for this room? just few small slots in each wall just like 2x4 panels? or all around the rom making angles? floor to ceiling?

it depends on the room modes. we can estimate based on the size what frequencies are most problematic, or you could measure the room (using Room EQ wizard or ETF for example) and we could determine what treatments you need - mode control, RT60, etc..

B.D.R. wrote:

2) " broadband " what slot size /tickness and space between slots for the broadband?

see #1

B.D.R. wrote:

3) Polys, how many and what size poly for this room?

in this case, you might construct poly's across each corner of the room to add diffusion and broadband bass trapping. straddle the corners with the poly. leave the back of it open and line with insulation. seal the top and bottom. if you can go floor-ceiling, even better.

To be honest I don't really know what frequencies are most problematic, all the measurement depend on the mic position look different, I don't have enough experience for figuring out the most problematic frequencies, Yes I guess I can learn how to use one of this Helmholtz calculators floating around, that's not a problem I think... but what frequencies are most problematic? I provided enough measurements for this purpose?

two things to look for: one - room modes which are the large dips or peaks in the response below 300hz. second - the high frequency reverberation times and/or echoes. the room modes are handled by the low frequency traps, and the mid and high frequencies are handled by the diffusion and slats. the slats would be tuned if there were problem frequencies that needed adjustment, otherwise you would target them to be more broad and balance the room. in the ideal world, the measurement line would be flat or slightly tilted to favor the ears ability to hear certain frequencies (bass usually needs to be a bit higher than high frequencies so most people opt for longer RT60 on bass frequencies than on high ones...) in your case, you have some modes as Jeff points out, and a couple of mid points that may be taken care of with broad treatments. otherwise the high end is reasonably flat so you just want to adjust for reverberation which requires some careful use of absorption to get it to the right level without over doing it. this is where the waterfall plots can help (although you ear is the better guide - which is one reason why Jeff asks you about how the room sounds...) from a process standpoint, I'd say get the bass modes flattened a bit, then work on the mid-high RT60 with some absorber panels. you've been doing a good job with the measurements but you want to work those corners, treat all the corners of the room.

gullfo wrote:

........................................ from a process standpoint, I'd say get the bass modes flattened a bit, then work on the mid-high RT60 with some absorber panels. you've been doing a good job with the measurements but you want to work those corners, treat all the corners of the room.

thanks for the overview Glenn And this is exactly my point, how I'm going to work those corners...? "I want to flatten this modes before they multiply... I don't understand my measurements... In the past I spent over $700.00 in Lenrds !!! And now after all, I'm learning that just (4) , 1/8 tick ceiling tiles total cost $16.00 do probably better job, I guess.... look below... P.S. I apologize, I noticed that my picks are slightly wider than 700, about 768..., sorry, I will re-size all, just give me some time to fix this. If just 68 wider it's not a big problem please let me know.