Room Measurements...Can I stop now?

dwillis45

Número sesenta nueve
I've been reworking my recording room and I'm stuffed. I'm not sure if I could build another bass trap or measure my room one more time. I've managed to control the low end (45hz-400hz) to within an 8db range and my frequency response looks reasonably flat at 1/24 or 1/48 smoothing. My waterfall indicates only limited ringing at or under 55hz, and much of that can probably be attributed to the noise floor. And the impulse response seems okay--At least judging from standards that I can discern online.

Of course, the room is dead as a doornail (see Topt) and I know this irritates some folks. Personally, I like things a little comatose, and this may be largely unavoidable in a small room setting. I may start adding slats or perhaps exploring diffusion, but I think I need a break. Besides, I think I need to record something before I become a complete engineering geek.

So...what say you? Should I push on in the hope of achieving +/-6b? Is there such a thing as too much bass trapping? Will I die from 703-related cancer? Should I start a Go Fund Me page to raise money to buy a half dozen GIK Scopus T40 tuned traps to attack the low end ringing which is probably noise? And what about the other end of the spectrum? Should I even care?
 

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:laughings:

I went through that same madness a couple of summers ago when I was building my big bass traps.
Ran the REW tests over, and over, and over, and over...and OK..that's enough now! :D

Since they are movable bass traps, meant for a few uses...I moved them around the studio and tried a dozen or two positions, with minor adjustments...and did multiple REW measurements every time. :facepalm:

Yeah, I saw differences, same as you have...but in most cases, as I adjusted to improve one thing, the measurement would get worse in another area...and it was really small stuff. I mean...there were only a couple of deeper/higher nulls/nodes that I was chasing, and once I was able to get them better balanced out...I just went with the best average, and the positions that also made the most sense. I think people sometimes go insane and just stuff the shit out of their rooms with treatment, only to improve things by 10-15%...because at the end of the day, the physical space doesn't change, and that has the biggest effect, and not 2-3 more traps here-n-there.

Now as I get ready to build a new studio...I'm really looking forward to doing all the REW measurements and positioning traps all over again......NOT! :p
 
:laughings:

I went through that same madness a couple of summers ago when I was building my big bass traps.
Ran the REW tests over, and over, and over, and over...and OK..that's enough now! :D

My only regret is that I didn't keep a running log of the cost (including time) involved in the process. That way I could have come up with a series of econometric measures showing the marginal cost of each change or improvement. If I had to guess, I would estimate that it costs roughly $100-$200 dollars per db of improvement. And this doesn't factor in the treatments that simply didn't work or couldn't be repurposed. I did all the work myself and I even canabalized a few of the traps to build new ones. And, still, the bills just kept adding up. It was a good experience and I learned a lot but I'm with you on repeating the process. No thanks. Moving a waterfall is like, well, moving a waterfall. It might be easier (and cheaper) to move Niagra Falls.

On the other hand, it's hard to imagine putting a room together without measurement. I tried by following all the usual suggestions regarding placement. Eight foot by six inch 703 traps straddling the corners, panels at the first reflection points, a cloud at the mix position, etc, and I thought I was at least 80 percent there. It turned out that I wasn't even close. And that's a scary thought, especially for the uninitiated who build based on theory and stop short of testing.
 
Yeah...do the initial measurements (when your room is full of gear, not empty)...add some traps...measure again...add some more...measure again...
...then call it a day, and get back to the music.

The pros building multi-million dollar studios for top-shelf clients...they can afford to tweak things to absolute perfection, especially if they are building from the ground up, because then you have full control of all the elements, and even then, things don't work out perfectly.
At the home studio level...it's like pissing into the wind, and hoping you can avoid the blowback! :p
 
LOL. Saturday morning I'm going back in. I just upgraded my monitors to a pair of Adam A7x's. Mostly, as a treat for spending so much time and insulation trying to get the room to sound right. :D

Logic tells me that when I measure the room I will probably get very similar results. Although you never know. My old monitors don't have quite the same range as the A7x's and they are at least 15 years old. So they could also have performance issues. The crossover frequency is about the same (2.5k and 2.6k) but I'll let the numbers speak for themselves. Hopefully, I won't have to redecorate. :D

Then I get to spend a couple of days burning-in the new monitors and listening to reference material. After that, I guess I should measure again. But I swear, that's the end of the line. :D
 
I've been reworking my recording room and I'm stuffed. I'm not sure if I could build another bass trap or measure my room one more time. I've managed to control the low end (45hz-400hz) to within an 8db range and my frequency response looks reasonably flat at 1/24 or 1/48 smoothing. My waterfall indicates only limited ringing at or under 55hz, and much of that can probably be attributed to the noise floor. And the impulse response seems okay--At least judging from standards that I can discern online.

Of course, the room is dead as a doornail (see Topt) and I know this irritates some folks. Personally, I like things a little comatose, and this may be largely unavoidable in a small room setting. I may start adding slats or perhaps exploring diffusion, but I think I need a break. Besides, I think I need to record something before I become a complete engineering geek.

So...what say you? Should I push on in the hope of achieving +/-6b? Is there such a thing as too much bass trapping? Will I die from 703-related cancer? Should I start a Go Fund Me page to raise money to buy a half dozen GIK Scopus T40 tuned traps to attack the low end ringing which is probably noise? And what about the other end of the spectrum? Should I even care?


you gotta know when to hold and when to fold them

you have measured enough

now go make music
 
you gotta know when to hold and when to fold them

you have measured enough

now go make music

Good philosophy and I take it to heart. I've been recording through the whole process. I just haven't been able to record at the same pace. Measuring and building is a massive time suck.

Still, I feel like I'd be remiss if I didn't take one last set of measurements to look at the impact of the new speakers. It seems like a potentially important variable and it's just one last dose of REW heroin. I swear I'm going to rehab as soon as I'm done. :D
 
D,
If you are so inclined, I would be interested in seeing a pic of the final product that produced those REW results. Mostly, for me, to see how your placement(s) are interacting to produce those flat results.
Dale
 
D,
If you are so inclined, I would be interested in seeing a pic of the final product that produced those REW results. Mostly, for me, to see how your placement(s) are interacting to produce those flat results.
Dale

There is a post somewhere in this sub forum called "Studio pics."

Studio Pics

The photos don't really show everything that's in the room. But you will get an idea. Keep in mind that this is just one 20x20x8 garage. Other rooms with other dimensions need other treatment approaches.
 
Not surprisingly, the new results are not too far off the originals posted above--at least for the low end under 250 hz or so. And that's a good thing. Part of me was fearing the new test, thinking that I just spent too much money on new monitors only to get a worse result. Of course, I'll probably repeat the test after the speakers are burned in. Again, I don't really expect too much difference. But a variable is a variable. :D
 

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Some things in the high end, however, did change. It turns out that the new Adam A7x's seem to perform better above 400hz than the old Event PS6's. They are flatter and a lot less "hyped" in the range from roughly 400hz to 2k. (see plot below. RED=EVENT. GREEN=ADAM). The Adam monitors also seem to do a better job sorting out the crossover point to the tweeter. Both monitors list crossover points at about 2.5 to 2.6k. But, at this particular frequency, the Events seem to take a dive followed by a serious peek in-between 4 and 6k. All in all, this transition is much smoother in the Adams.

Of course, the Adam speakers cost $1,500 bucks. For that much, they need to be flat and fetch my morning coffee. :D And it may be that some of this is just window dressing. Many people argue that the human ear/brain does most of the heavy lifting in the upper mid and high frequencies. Psychoacoustics solves many issues and the may be one of them. Still, I like to see flat. I paid for flat and I want flat.
 

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I've read about, and seen the measurement images for your space, but the one thing you have not said is a very important one. What does a commercially mastered CD sound like when you play it? I have never measured my current recording space. I see no need to at all because it sounds the same as the last one, and the same as the one before that. Every time I built a new studio, I just added things to make well known tracks sound the same, and even though this one is a little smaller, it's very close to what I know, and all my old stuff sounds exactly like it did (at least, in my head). It's actually a bit bass light - most mixes sound more bassy when played somewhere else. This small issue my brain deals with. I suspect you have got totally hung up in the measurements, and I also think your measuring regime is itself flawed.
I paid for flat and I want flat

I would bet that if you take your speakers and measurement kit into the middle of a football field and do the test, you will NOT get a flat response. It just won't happen. Is your measurement mic really flat? I doubt it. Your loudspeaker will have peaks and troughs, so will the microphone - but this depends on the resolution scale you set. Is a 1dB increase, that you cannot hear, a hump. If it coincides with a 1dB hump in the mic's response, you start to have a mountain range on the screen - but is it real. You sound like what you want is an anechoic space, with a physically impossible speaker plot, recorded with a perfectly flat mic. You are chasing your tail, and it's not a realistic goal.

I have some large theatre sized PA systems - subs, then two bands above. Electronic crossovers, and computer gadgetry. Playing a noise source, and using a mic gives me a start when I set up a crossover. However, the final tuning is rarely when I get a mostly flat response on the screen. In fact, depending on the music I'll be using, I'm likely to change the crossover points and gains to each section to make the music better. If I'm doing a rock and roll show, then I've probably got kick in the subs, but if the bass player has a four string, then most of his bass will come through the LF section, not the subs - but if he has a 5 string, then the kick and the B string will be hard to move apart. If there are guitars and no keys, the LF to HF crossover point might be moved a bit too. The crossover can store these settings. My point is that best sound and flat response never seem to go together. The same applies in studio monitors. I'd like them to be truthful and musical. Ask yourself this question. if a flat response measurement microphone is the best one for measurement purposes, then why don't we use them to record voices or instruments? Flat is not some kind of mythical chalice. Flat is good as a starting point.
 
I've read about, and seen the measurement images for your space, but the one thing you have not said is a very important one. What does a commercially mastered CD sound like when you play it? I have never measured my current recording space. I see no need to at all because it sounds the same as the last one, and the same as the one before that. Every time I built a new studio, I just added things to make well known tracks sound the same, and even though this one is a little smaller, it's very close to what I know, and all my old stuff sounds exactly like it did (at least, in my head). It's actually a bit bass light - most mixes sound more bassy when played somewhere else. This small issue my brain deals with

Yup. I get that. But that's not how I'm wired. I like to see things along with hearing them. I also lack confidence in my own ears, particularly at age 60. My hearing changes routinely depending on all kinds of variables, including how often I swim and how often I have ear wax removed by my ENT. I'm also suspicious of those who simply use their ears and make a judgement. Many people claim this power and it may be true. But I hear it all the time and I'm wary. I like the theory that years of experience can train the human ear. But without delving into the psychoacoustics literature, I have no evidence to verify this generally accepted wisdom (or myth).

It's a lot like when my wife feels sick and asks me to take her fever by putting my hand on her head. She's a mom and after years of raising children, she can "feel" fever. Me I reach for the thermometer just like they do at the hospital or a doctor's office. For me, it's all about some level of exactitude. I'd like to know whether the fever is 100 degrees or 104. It makes a difference.
 
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I suspect you have got totally hung up in the measurements, and I also think your measuring regime is itself flawed.

Only partially hung up. Kind of like the guy who keeps buying equipment or records vocals even though he knows he can't sing. It's just a way of passing time and showing proof of life until I pass on into the netherworld. Everybody has to have an interest or a passion as the Millennials call it. And I believe that you benefit from both interest and intensity. I doubt very seriously that I will become a room designer or measurement guru. But for right know it's interesting and, one hopes, useful. That's why I've made repeated reference to addiction and REW as heroin in this thread. I'm not hung up. I know my demons and room measurement isn't one of them. :D
 
I would bet that if you take your speakers and measurement kit into the middle of a football field and do the test, you will NOT get a flat response. It just won't happen. Is your measurement mic really flat? I doubt it. Your loudspeaker will have peaks and troughs, so will the microphone - but this depends on the resolution scale you set. Is a 1dB increase, that you cannot hear, a hump. If it coincides with a 1dB hump in the mic's response, you start to have a mountain range on the screen - but is it real. You sound like what you want is an anechoic space, with a physically impossible speaker plot, recorded with a perfectly flat mic. You are chasing your tail, and it's not a realistic goal.

I also get the flat earth argument. :D And I should say what I mean: relatively flat or flat within reason. My statement that, "I paid for flat and I wan't flat," was simply a joke. It was a reflection of the misconception around here and everywhere that you can buy yourself out of problems. Americans more generally believe this credo and so I'm not surprised that it has seeped into the recording world.

Again, I'm looking for some visual evidence that there are no horrible problems lurking in my studio. To use the medical analogy again, it's just a check up--a way of taking some blood and perhaps an x-ray or two. I'll follow up with ears as I move on.

And, yes, I get the whole B&K curve thing. So I suppose I should say relatively flat with a generally downward slope of several db. :D
 
Yup. I get that. But that's not how I'm wired. I like to see things along with hearing them. I also lack confidence in my own ears, particularly at age 60. My hearing changes routinely depending on all kinds of variables, including how often I swim and how often I have ear wax removed by my ENT. I'm also suspicious of those who simply use their ears and make a judgement. Many people claim this power and it may be true. But I hear it all the time and I'm wary. I like the theory that years of experience can train the human ear. But without delving into the psychoacoustics literature, I have no evidence to verify this generally accepted wisdom (or myth).

It's a lot like when my wife feels sick and asks me to take her fever by putting my hand on her head. She's a mom and after years of raising children, she can "feel" fever. Me I reach for the thermometer just like they do at the hospital or a doctor's office. For me, it's all about some level of exactitude. I'd like to know whether the fever is 100 degrees or 104. It makes a difference.


many home thermometers are very inaccurate

i would trust how i feel or how my hand felt on the kids forehead more than a typical drugstore thermometer
 
I too am 60. My hearing I keep track of carefully, and it's still quite good, although the top end is creeping down slowly. I had them tested recently by an audiologist linked to the Musicians Union here in the UK - they are on a quest to protect musicians hearing. My results were pretty good, and they also took moulds for hearing protection and my in-ears.

I listen, and then if confused I'll use technology to make sense of what I suspected. You seem to have this reversed, you are happy with the sound but need visual confirmation that what you hear is correct. One thing I do know - every piece of technology that is not calibrated and certificated is merely an indicator. My phone, for example - has a number of ads to keep track of volume. They all address the same microphone and all give totally different results. Chasing your tale, to get flat - and I really think you didn't 100% make a joke about flatness, some truth in there, I think = money going out, doubts creeping in and unhappiness. I mix - Im listen on my monitors. Speakers I have had for a long time and know well. I then listen on DT100s, headphones I know well, and then I may listen on my band IEMs (Shure 215s) They all sound broadly similar but each has character. Which is right? No idea.
 
many home thermometers are very inaccurate

i would trust how i feel or how my hand felt on the kids forehead more than a typical drugstore thermometer

A lot of consumer medical equipment is inaccurate. Automatic blood pressure cuffs, for example, often inflate BP by as much as twenty points. That's probably why many physicians prefer the old school method using a BP meter and a stethoscope. Notice, however, that you don't see a lot of doctors who will estimate your blood pressure just by looking at you. And I've never seen a nurse or a hospital CNA take vitals using a hand on the forehead.

Science, technology, and progress are often about measurement and the development of devices to measure things more accurately. It's one of the small ways we move forward as a civilization.
 
A lot of consumer medical equipment is inaccurate. Automatic blood pressure cuffs, for example, often inflate BP by as much as twenty points. That's probably why many physicians prefer the old school method using a BP meter and a stethoscope. Notice, however, that you don't see a lot of doctors who will estimate your blood pressure just by looking at you. And I've never seen a nurse or a hospital CNA take vitals using a hand on the forehead.

Science, technology, and progress are often about measurement and the development of devices to measure things more accurately. It's one of the small ways we move forward as a civilization.

doctors and nurses have an industrial strength temperature gauge they stick in your ear and push a button to get an accurate reading
you could buy one of those for home but most people choose the cheaper option
and for home use the hand works good enough. only if it is real hot do we break out the thermometer to get a value.
 
We are probably closer than you think on these issues. Again, I'm not putting all my eggs in the measurements basket. I spent a long time (2-3 years) recording and mixing in my space and listening on headphones (Senheiser HD650's, AKG 240's, etc) and monitors. I was never completely confident or happy with my recordings and I became more interested in the impact of room acoustics on the final sound. As I noted in another thread, I've been down the equipment road, the recording techniques road, and the mastering road looking for solutions. I've solicited the aid of a mixing engineer to see if an outside studio impacted my work. And I've tried listening, thinking, researching, and talking about audio and recording until I was blue in the face.

As a result, my interest in room acoustics is really a sort of a last stop in the home recording train. Measurement is just part and parcel of that process. It's another way of thinking about what happens when we record by looking at the fundamentals of sound. It's also just another sub-hobby buried under the larger umbrella of recording. Some people make guitars, some people build studios, some play in bands, and many go shopping. If I had to write music and record it on a daily basis, I would be institutionalized. Or perhaps lop of an ear. So things like room measurement fill the void. Besides, the pictures are really pretty. :D
 
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