Ok, got some analysis results for you, and it ain't so pretty.... take a deep breath, and take a seat...
First, here's the true frequency response, smoothed to 1/48 octave, at the mix position:
As I expected, there are some pretty wild swings in there, +/-10 dB. Mostly in the lows, but also in the low mids, as well as a steep roll-off in the highs, above 12kHz. Perhaps that's the rug, or it might just be speaker-related.
Here's the graph at the client position:
Even WILDER swings! +/-20 dB! Not an accurate place to be sitting at all: And the bass build-up is clearly evident.
Now a comparison of both, for the low-end of the spectrum (which is the most critical):
Blue is mix position, red is client position. Comment: Ummmmmm..... :shock: :)
There's a major difference in the low mids. And I mean MAJOR! The client is not hearing the mix anything like youa re hearing it. For him, there's a hole in the vocals and low end of guitars, the snare sucks,, and the bass is booming... as compared to what you are hearing, which is also not accurate....
OK, those are just a tiny part of the situation, since they are only frequency response. Now for the important stuff...
Waterfall plot of the low end, at the mix position:
Hot damn! That's pretty poor, and indicative of a major lack of bass trapping.
You have clear modal issues at 51 Hz, 56 Hz, 102 Hz, among other possibles, and they are strrreeeettttchhhiiinnnngggg out way far in time. (I've got the cut-off set to 300 ms for that view). Lot's of not-so-nice stuff going on in the low end. There are also signs of flutter echo in the low end, and a heap of other stuff.
And no the same waterfall plot, but for the client position:
To be honest, I would hate to b sitting in that location, trying to make critical decisions about the mix.... The room is lying to your client: he is not hearing anything at all like what is coming out of the speakers.
The spectrogram presents the same time-domain data in a different format, that is also very interesting:
You can clearly see the large amount of unevenness in the low end, with major differences in decay times, all across the board.
Also, your sub is in the wrong place.... It either needs to be moved, or your mains need a time delay on them.
Now for the overall RT60 graph:
Not so smooth, too bright overall for that room, and with a large rise in the decay times in the low end.
And finally, the actual impulse response itself:
Ouch! There's no ITDG at all, and some very prominent early reflections throughout the Haas time, even up to about 40 ms! That's screwing up your stereo imaging, sound-stage, and sweet spot.
For the client position, the IR is even worse:
That's scary. To me, it looks like the client position is totally outside the direct field, with numerous reflections in the Haas time, and something that you don't see too often: reflections that are more powerful than the direct sound. Here's a close up of the first 12 milliseconds, which show it very clearly:
At about 2.7ms, there is a very strong reflection that exceeds the direct sound level by several dB, plus several other reflections. There's no way that your client is getting an accurate stereo image.
So overall, that room needs some major treatment and re-arranging to make it usable. It is more or less what I expected, and nothing like your graphs show, because you over-smoothed them and used scales that don't mean much. These graphs show the acoustic reality of your room, and clearly it needs fixing.
And it turns out there's nothing at all unusual happening at 153 Hz.... !!! :!: 8) The closest issue is what appears to be some modal ringing at 143 Hz, but that's a long way from 153.... It's two notes down the scale.
There's no impulse response files in there, so I could not look at it, but in fact the tests do nned to be done with the sub on. Also, you are doing your tests at a level that is too low: it needs to be done at around 85 dB for each individual speaker, but yours were done much lower than that (assuming you calibrated your system correctly before doing the tests). 85 dB is typical mixing level, and doing the tests at a lower level might not have triggered all the modes. Also, if you repeat your tests, please do one with just the left speaker, one with just the right, one with just the sub, and one with all three of them. That reveals a lot more detailed info about the room, such as problems with symmetry, or problems with cross-overs, interference between sub and mains, etc.I just realized it may be better to do these tests without our subwoofer on... I've re-performed the tests with it muted:
Right, but those are added at the end of the room tuning process, as a final tweak, and they are done for specific purposes.I've definitely seen carpet & rugs in lots of top studios (capitol, westlake, paramount)
Carpets do the exact opposite of what most rooms need. Carpets are pretty good at sucking up the high end, mess up the mid-range randomly, and do nothing at all for the lows. Whereas what rooms need is major absorption in the lows, some controlled treatment in the mids, and practically nothing at all in the highs. A carpet in your room will skew the acoustics towards the low end, so that it sounds "muddy", "boomy", "lifeless", and similar terms.so is there something inherently bad about this placement? Perhaps a rug is better suited in the back of the room?
... and they are frequently mis-used in many studios. Read the book by Cox and D'Antonio, the guys who did all the initial research on how diffusers work, how to tuned them, how to use them, etc., and wrote many papers on them. Numeric-sequenc diffusers produce a pattern of lobing around them, in both the frequency and time domains (implying phase domain as well), with levels varying greatly between lobes. They are the ones who came up with the rule that your ears should never be within ten feet of a numeric-sequence diffuser if you are doing critical listening, since the lobing artifacts totally mess up your brain's ability to determine directional and tone. Just moving your head a few inches one way or the other will put your ears in very different lobes, and you will have vary different perception, for the exact same sound. Their research revealed that at about ten feet the lobes are fairly well merged, so the effect is no longer important. However, in addition they discovered that if your head is within three wavelengths of a particular tone, then you would be suffering from the same issues, so they also suggested that you should be at least 3 full waves distant, for the lowest tuned frequency of the diffuser. Later the changed that to 7 full waves, as they discovered that scattering can still happen for an entire octave below the cut-off frequency. You say that the cut-off for yours is 325 Hz, which is a wavelength of 3.5 feet. Therefore, you should not have a listening position with 10.5 feet of that, based on their old rule, or 24.5 feet based on their 7-wave rule... Yes, you do see many studios with diffusers right behind the listening position, but you also see many studios with speakers on the meter bridge, and others with egg-crates on the ceiling, but that does not make any of that right! Not everything you see in studios is acoustically sound. Many studios just do things because they saw it done in another studio, but don't have a true understanding of why it was done, or how it was done. Acoustic treatment is not transferable: You can't just take something you see in one room that sounds good, and assume it will work in another room: all rooms are different, and each needs it's own specific treatment. The only time you'd be justified in copying treatment used in someone else's room to your room, is if your room is identical to theirs: exactly the same dimensions, same building materials, same speakers, same everything. If your room is a different shape or size, or is build differently, or has different speakers, or different furniture, then very likely you would not be able to "cut and paste" something from another room.[ diffuser ] It's there to help with echos I was hearing in the back of the room, and that's where I usually see them in studios..
Nice! I would definitely use those as your mains, but set them up correctly for that room, then treat the room accordingly, then tweak.The mains are Focal Trios.
The desk is part of the problem: I would replace that with a low, flat desk. All that stuff sticking out on top is messing with your clarity.I've been tweaking all this constantly, so no logic here other than trying to use this desk as effectively as possible,
Ears are great... but nowhere near as precise as a proper acoustic analysis: Plus, a big part of the reason why you have not been able to find good locations for your speakers, is because the room response is preventing you from doing that! You will never be able to set up your speakers correctly by ear in a room that lies to you. No matter where you put them, there will be some problem. And no matter where you put your head, there will be other problems. Until the room is treated to get the acoustics under control, you will not be able to get your speakers in a position that is accurate. It's sort of like asking an artist to paint a picture while he is wearing glasses with one lens colored pink, the other colored blue, and while you are shinning multi-color lights on different parts of the canvas, which is itself stained with coffee, dirt, blood, mustard, and ketchup! No matter how hard he tries, or how good he is an artist, he will never be able to paint a picture like that. It might look great to him, under those conditions, but when he takes off the glasses and takes his painting outside into sunlight, he'll see just how terrible it is.and going by my ears.
That would explain some of the comb filtering seen in your frequency response, ans well as the SBIR issues.The tweeters of the Focals are about 4.5' from the front wall currently.
Absolutely it is relevant! Everything matters. When I'm designing a room, I very often need to re-do the whole thing because the client told me was going to switch out his speakers, or desk, or console, or furniture, or whatever for something different. Anything that changes in a room could potentially affect the acoustics. The bigger the change, the greater the effect. Just getting all of the junk out of your room and cleaning it up is going to make a difference... but probably for the worse.... :) I'm not sure what your goals are here, but if you want your room to be as accurate as possible, with world-class acoustics, I would suggest that it needs a major re-design, in terms of layout, geometry, and treatment. First you should decide on what equipment and furniture you want in there, then on the best places to put it (both acoustically and also ergonomically, as well as aesthetically), and based on that do the actual basic layout design. With that in place, then you can look at the geometry of the relationship between the speakers, the listening position, and the room: Based on that you can predict what basic treatment will be needed, so you can design that and put it in place. They you can test and analyze the room (as I did above) to see what still needs to be done, design new treatment for that, install it, test, rinse, repeat.... That would be my suggestion. Have you considered soffit-mounting your mains? That would work VERY well in that room... :)Planning to adjust all this and move things toward the front of the room once we get the console situation sorted. I'm hoping all this data is still relevant even though we're planning to move things around in the next month.
Don't worry! I didn't take it that way at all. My answer was part joking, and part serious. It's hard to express emotions over the internet... :)Sorry! Wasn't trying to come off as arrogant...
I love a good challenge, and your room clearly has some challenges. It's a nice size, and you have decent equipment, so it can be made to sound pretty darn good, if you want it to. - Stuart -and I can't thank you enough for taking interest!