Linkwitz Orions beaten by Behringer.... what!!?

But one still cannot resolve anomalies by EQ that are the result of the superposition of non-minimum phase signals.

Which is not entirely correct. Please read the Dirac paper I've linked.

Furthermore, rooms do exhibit minimum phase regions. Mostly at lower frequencies. Please see Minimum Phase
In REW you can generate a "excess group delay". The flat regions in those plots are minimum phase and can be equalized.
 
Gedlee,
I thought that you said your floor and ceiling was a hard surface, so I guess I misinterpreted that to mean that they were not treated. I guess we all read things into statements that aren't there, assumptions.

Much of the confusion could be elimiated if Earl would document his room on his website. After all it is an essential part of his speaker design. Unfortunately there is nothing. No pictures, no measurements, just anecdotal evidence.
 
Room acoustics is linear. Time invarient is less clear and depends on to what order one means this statement. There will be thermal changes to the speed of sound that will vary in time as currents move about a room, but for the most part these can be thought of as "small". "Negligable" requires that we be clearer in what we are looking at. The fine structure of a room FR at higher frequencies, while being random, is not necessarily stationary. Over some bandwidth it will be to any degree that one desires however.
I guess this applies well to horns, eminently bass horns where compression follows thermodinamic laws
 
You were clear and I understood completely and I agree completly.
We really agree about most things in audio.
I appreciate your ability to stay objective and not succumb to the common and popular subejctivism.

Not only does researches tell me that there's a clear correlation between accuracy and what sounds good, but all my own experiences verifies it.

markus:
Though I have read parts of the Dirac article I don't need to read a paper from someone who sells room correction to explain to me this. Learning about acoustics, how the speaker and room interact, a well defined acoustic concept as a goal, you clearly see the limitations of room correction.
EQ has it's place, but one also need to understand that there are clear limitations. And I'm in that perfection band. ;)
 
Though I have read parts of the Dirac article I don't need to read a paper from someone who sells room correction to explain to me this. Learning about acoustics, how the speaker and room interact, a well defined acoustic concept as a goal, you clearly see the limitations of room correction.

well, maybe not active, but it seems you read a lot about passive correction.. And obviously there never is any links with the people selling acoustic materials? ;)
 
Though I have read parts of the Dirac article I don't need to read a paper from someone who sells room correction to explain to me this. Learning about acoustics, how the speaker and room interact, a well defined acoustic concept as a goal, you clearly see the limitations of room correction.
EQ has it's place, but one also need to understand that there are clear limitations. And I'm in that perfection band. ;)

I'll remind you next time you cite something from Toole, Keele, Geddes or...

Anyway, the claim that a room doesn't behave as a minimum phase system is simply wrong. It can and has been shown that there are minimum phase regions. Good luck with dampening modes below lets say 100Hz by passive means.
 
Oh, that's easy. And good luck with lowering decay and taking care of resonances/ringing without it!

Passive absorption below 100Hz is easy? Maybe easy to know what is necessary to do it but when it comes to implementation most people can't do it for practical reasons.

Back to minimum phase. The beauty of a minimum phase is, if the magnitude response is corrected, then the time domain is corrected at the same time. In other words, when there was ringing and the accompanying peak has been flattened, the ringing is also gone.
Here's an example: Hard proof that equalization kills roommodes - Blog - Acoustic Frontiers

Just read one of the next posts on gearslutz.com from where you took your former quote: Gearslutz.com - View Single Post - Your opinion about room correctional software

By the way, who is "SAC"? Why do you think he has more credibility than some Dirac guy?
 
Oh, that's easy. And good luck with lowering decay and taking care of resonances/ringing without it!

you need both my friend! I would have expected you to know this.. Passive correction does take care of the time issues, but try to get a LF resonance 10 or 15db down with floam.. Something that is so easy to do with Eq! :rolleyes:

And you still keep talking of "accuracy"?
 
Look. I don't mean to be rude, but you seriously need to broaden your understanding of acoustics.
You can run around looking for simple answers do deal with bass problems to avoid doing what you feel you can't do. Dipoles, room correction, multiple subs etc. But you will never end up with a great result that way.
Remember that I initally said what I said about room correction from a perspecitive of a high standard.

I wouldn't say by the way that something sticking out 10 cm into the room is obtrusive and very large. But if foam is all you think is used for treatment, I can understand why you say so.

But sure, I know everyone can't treat the room. You will however also end up with a very mediocre result no matter what magic room correction or bass solution you apply.
 
Look. I don't mean to be rude, but you seriously need to broaden your understanding of acoustics.

Funny. Did you read ANY of the links I've provided? It would broaden YOUR understanding of acoustics.

CABS delivers results that are virtually free field. Near field subs is close. No room treatments were harmed during those experiments.

Rooms exhibit minimum phase behavior. You can bury your head in the sand but physics won't change by doing so.

Like reality isn't just black and white, acoustics isn't about room treatments vs. equalizer.
 
Omholt, is this your room?

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Funny. Did you read ANY of the links I've provided? It would broaden YOUR understanding of acoustics.

CABS delivers results that are virtually free field. Near field subs is close. No room treatments were harmed during those experiments.

Rooms exhibit minimum phase behavior. You can bury your head in the sand but physics won't change by doing so.

Like reality isn't just black and white, acoustics isn't about room treatments vs. equalizer.

Rooms are not minimum phase. Rooms are rooms. To first approximation reflections are linear, and sound transmission in air is linear.

This qualifies rooms as linear and time invariant. A minimum phase impulse response emitted in room and measured from within the room results in impulse response that is a linear combination of reflected impulses and is specific for speaker and microphone location, and is not minimum phase.

Reading is one task, comprehension is another.
 
Rooms are not minimum phase. Rooms are rooms. To first approximation reflections are linear, and sound transmission in air is linear.

This qualifies rooms as linear and time invariant. A minimum phase impulse response emitted in room and measured from within the room results in impulse response that is a linear combination of reflected impulses and is specific for speaker and microphone location, and is not minimum phase.

Reading is one task, comprehension is another.

I don't see any listener located in the room ...
What's happening in there ?
:rolleyes::(

I'm waiting the 11th of april to see the movie 'Oblivion'
where the Earth is inhabited by drones
are those the target listeners ?
 
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Rooms are not minimum phase. Rooms are rooms. To first approximation reflections are linear, and sound transmission in air is linear.

This qualifies rooms as linear and time invariant. A minimum phase impulse response emitted in room and measured from within the room results in impulse response that is a linear combination of reflected impulses and is specific for speaker and microphone location, and is not minimum phase.

Reading is one task, comprehension is another.

So basically you're saying this analysis is wrong:
Minimum Phase

Would you care to elaborate?

Regarding LTI, what about all the (resonating) items that usually occupy a room?
 
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It has been proven (see Jont Alan in JASA) that in theory no room can be minimum phase. That said, most rooms are nearly minimum phase at LFs, just as Markus has shown. The only region where they are not minimum phase at LFs is near a null. This is because a null is not possible in minimum phase circuits so the concept fails near these aberrations. I think that it is perfectly reasonable to assume that a room is minimum phase in the modal region, but to extend that same assumption above those frequencies is a serious error.