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Post by pianoprodigy on Sept 1, 2016 11:16:44 GMT -5
In theory, if you had a room setup with "perfect" acoustics and then ran DIRAC, would the degree of improvement be minimal to non-existent? Conversely, if after running DIRAC, the room sounds dramatically different (not in all ways "better"), does that mean that the starting point of the acoustics of the room is very poor? I have dual JTR Orbit Shifter subs and I feel that the bass is terribly boomy in the room. This is improved somewhat after DIRAC but the bass also feels gutted and in many ways, it sounds worse than with no processing at all. I'm trying to evaluate how much room correction I want to do with quality panels and such and trying to analyze just how "bad" my room really is in a more-objective manner. Thanks.
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KeithL
Administrator 
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Post by KeithL on Sept 1, 2016 16:48:02 GMT -5
By definition, if your room, and your speakers, were perfect, then there would be no improvement POSSIBLE, right? In general, what you can expect from Dirac is to bring your room, and the rest of your system "closer to perfect". This means that, if they're already perfect, then it isn't going to be able to do much of anything. And, if your setup is "pretty good" or "very good" to begin with, then Dirac will make it better - possibly a lot better. And, if your system has really serious problems to begin with, while Dirac may be able to improve things a bit, it can't perform miracles. In the context of subs, it is quite possible to have a situation where, due to the room itself, or the locations you've chosen for your subs, there is a "fatal problem" that not even Dirac can fix. The usual answer is that you should do your best to optimize things as much as possible BEFORE running Dirac, to give it the best possible starting point to work FROM. One important consideration is that ANY room correction system, including Dirac, is best able to deal with wide "dips and humps" in frequency response, but will have more difficulty with very sharp peaks, and a lot of trouble with deep nulls. It's not that it won't be able to fix those sorts of issues, which it may or may not, but that the fixes are likely to result in other problems.... which sounds like what you're reporting. Therefore, if you have sharp peaks at certain frequencies, or deep narrow notches where the bass just plain sucks out, you should try to reduce those by moving your subs around before running Dirac. (I can see that it may not be possible to move those subs around.... and they seem to really want to be corner loaded.... ) [For anyone else reading this, these seem to be 24 cubic foot, 200 pound, horn loaded monsters originally designed for large-scale sound reinforcement applications.] The one "drawback" to Dirac is that it will do its best to make a "total correction". If you find that Dirac is unable to make corrections that satisfy both it and you, you may consider using the manual EQ controls to make more "strategic" corrections to just the problems you find especially noticeable. (For example, use a simple EQ band to reduce their output around the range of frequencies where the most noticeable booming occurs.) In theory, if you had a room setup with "perfect" acoustics and then ran DIRAC, would the degree of improvement be minimal to non-existent? Conversely, if after running DIRAC, the room sounds dramatically different (not in all ways "better"), does that mean that the starting point of the acoustics of the room is very poor? I have dual JTR Orbit Shifter subs and I feel that the bass is terribly boomy in the room. This is improved somewhat after DIRAC but the bass also feels gutted and in many ways, it sounds worse than with no processing at all. I'm trying to evaluate how much room correction I want to do with quality panels and such and trying to analyze just how "bad" my room really is in a more-objective manner. Thanks. |
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Post by yves on Sept 1, 2016 17:36:48 GMT -5
Not to knock on Dirac or anything like that, but... a lot of people seem to often tend to forget the fact that the frequency response curve alone says almost nothing about how a room will sound like. A big room without any bass traps installed in it will, at certain bass frequencies (i.e. which frequencies they are will depend on the size and shape of the room, materials used, furniture, coverings, etc.) typically reverberate for more than 3 whole seconds so good luck with fixing those sorts of problems in software without actually making things even worse. ethanwiner.com/basstrap.html |
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Post by audiobill on Sept 1, 2016 17:43:37 GMT -5
Keith, DIRAC doesn't "correct your room" , at best it's a huge computer aided graphic equalizer.
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Post by yves on Sept 2, 2016 0:41:15 GMT -5
Keith, DIRAC doesn't "correct your room" , at best it's a huge computer aided graphic equalizer. Parametric, not graphic. But yes, Dirac Live can't let you individually EQ multiple subs so definitely there's still room for improvement (with the emphasis on "room"........) so not that much use to it until Dirac Unison arrives, and, even after that one will have arrived, there still won't be any miracles performed by anything unless people start to get really very serious about installing enormous bass traps everywhere they pretty much can. |
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Post by millst on Sept 2, 2016 11:01:40 GMT -5
As far as determining how "bad" your room is, you could start by examining your Dirac graphs. They show you the measured response and the correction that Dirac is making. The next level would be to take your own measurements with something like REW. I'd consider it a must if you're going to buy room treatment. You can't just slap a bunch of bass traps up. You need planning and before/after measurements to confirm your results.
-tm
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Post by fbczar on Sept 2, 2016 13:04:52 GMT -5
As far as determining how "bad" your room is, you could start by examining your Dirac graphs. They show you the measured response and the correction that Dirac is making. The next level would be to take your own measurements with something like REW. I'd consider it a must if you're going to buy room treatment. You can't just slap a bunch of bass traps up. You need planning and before/after measurements to confirm your results. -tm You can also use Dirac to help you determine the best speaker and bass trap placement. Just make one measurement from the sweet spot, move the speaker or bass trap and measure again. You can also use Dirac to help find the best "main listening position" in the same way. Just measure for one spot, move the microphone and measure again. It may be a good place to start if you are not proficient with REW. In addition, several companies that make bass traps will be happy to assist you if you can send them a sketch of your room. |
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ericl
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Post by ericl on Sept 27, 2016 19:00:11 GMT -5
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Post by yves on Sept 28, 2016 1:33:08 GMT -5
But what if my own ears are telling me (with certainty) that it doesn't always help? Let's not forget the fact that a studio microphone also picks up both the minimum-phase AND the non minimum-phase properties of the acoustic space in which the music is recorded, so spatial cues already present in the recording are going to be messed up by room correction software EXACTLY BECAUSE of injecting energy way beyond the natural-sounding. The addition of helper speakers will still not completely eliminate the timing related limitations (that our ears are sensitive to) despite that it will considerably help reduce modal ringing. Modal ringing in a room does have a minimum-phase behavioral character so it [modal ringing] lends itself better to room EQ. But like I said it isn't always that great at least not until multiple individually EQ'd (or should I say "filtered", or sound field managed) subwoofers will come into play, which is something that Dirac Unison will be able to. (That is, if those Swedish professors can manage to finally teach themselves how to stay out of the way of the music this time, eh...).  |
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Post by millst on Sept 28, 2016 10:45:43 GMT -5
Then you are free not to use it  -tm |
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ericl
Minor Hero
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Post by ericl on Sept 28, 2016 11:04:50 GMT -5
I'd say that if you and 5 other blind test listeners agree then you are correct.
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Post by yves on Sept 28, 2016 11:45:12 GMT -5
I'd say that if you and 5 other blind test listeners agree then you are correct. The difference is noticeable enough for blind listening tests to be not necessary.  |
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Deleted
Deleted Member
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Post by Deleted on Sept 28, 2016 11:56:06 GMT -5
Not to knock on Dirac or anything like that, but... a lot of people seem to often tend to forget the fact that the frequency response curve alone says almost nothing about how a room will sound like. A big room without any bass traps installed in it will, at certain bass frequencies (i.e. which frequencies they are will depend on the size and shape of the room, materials used, furniture, coverings, etc.) typically reverberate for more than 3 whole seconds so good luck with fixing those sorts of problems in software without actually making things even worse. ethanwiner.com/basstrap.htmlyou do know that for bass traps to actually work in the problem areas they would need to be 4-6' thick right? |
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Post by yves on Sept 28, 2016 14:18:58 GMT -5
Not to knock on Dirac or anything like that, but... a lot of people seem to often tend to forget the fact that the frequency response curve alone says almost nothing about how a room will sound like. A big room without any bass traps installed in it will, at certain bass frequencies (i.e. which frequencies they are will depend on the size and shape of the room, materials used, furniture, coverings, etc.) typically reverberate for more than 3 whole seconds so good luck with fixing those sorts of problems in software without actually making things even worse. ethanwiner.com/basstrap.htmlyou do know that for bass traps to actually work in the problem areas they would need to be 4-6' thick right? Supertips SuperChunk corner bass traps that are 34″ wide on the front face work very very well. In the example mockup I posted above, the floor to ceiling ones are actually 39″ wide on the front face despite that they look like they're only 29½″ because, adjacent to each one of them, on the side walls is a floor to soffit 9½″ thick pressure based bass trap so the soffit bass traps in each corner between the walls and ceiling are 27½″ × 19½″ in fact. |
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Deleted
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Post by Deleted on Sept 28, 2016 15:50:35 GMT -5
Those will be good for 80hz or so +. The major problems with bad ringing is in the 80hz> area. And the length of those waves requires SUPER thick treatments to work not web super chunk corner traps would help
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Post by yves on Sept 29, 2016 1:47:24 GMT -5
Those will be good for 80hz or so +. The major problems with bad ringing is in the 80hz> area. And the length of those waves requires SUPER thick treatments to work not web super chunk corner traps would help In practice, based on real world measurements they can work significantly better than basic acoustics theory and simulations have been capable to suggest. Most simulations and reasonings popular among those who think they understand something are flawed in that they only account for gas flow resistivity instead of both it and mass, they assume normal incidence instead of semi-random incidence and planar waves instead of the more complex propagation that occurs, and they also tend to ignore a myriad of other small details such as discrete frequency test tones vs. series of harmonics superposed on a fundamental, for example. Also note, standing waves in a room take some time to build up so the bass waves travel through multiple bass traps multiple times during this buildup—and after. P.S., I almost forgot to mention the most important one, which is the fact that a thick porous absorber behaves very differently if placed in a corner [where two or three hard reflective surfaces meet] vs. placed flat against a single hard reflective surface. Adding a thin membrane to the front face of a SuperChunk bass trap also changes the absorptive characteristics, as does varying the density and gas flow resistivity of the insulation material(s) with the depth position. |
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