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Your opinion about room correctional software Virtual Instrument Plugins
Old 21st June 2010
  #121
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How do you alter the Q/dispersion pattern of a loudspeaker using DSP?

I'm aware of beam steering in loudspeaker arrays using delays, but how do you do it in studio monitors?
Old 21st June 2010
  #122
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SAC: Please cut down to 1/10.

When you use the term "superposition" (not 100% correctly since the source is the same) talking about direct and reflected sound makes me wonder why you at the same time tells us that dispersion does not affect this summation.

That EQ-ing can not change time domain problems, remove modal nodes and such things has been mentioned several times already, no need to repeat that over and over. Noone seems to disagree.

In a normal room there are always tendencies that shows in a wider field than just the half meter around the listener.

The audible effect of moderating modal nodes with EQ is audibly positive.
Old 21st June 2010
  #123
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Quote:
Originally Posted by Dange View Post
How do you alter the Q/dispersion pattern of a loudspeaker using DSP?

I'm aware of beam steering in loudspeaker arrays using delays, but how do you do it in studio monitors?
There are several methods. What they have in common is, as with the arrays, you need more than one driver for a certain frequency.

BTW, why do you mix Q and dispersion pattern?
Old 21st June 2010
  #124
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Quote:
Quote:
Originally Posted by Brainchild View Post
At the same time, Rod has given his wholehearted endorsement to this statement:
Quote:
...[DSP] will not fix room acoustics but it can maximize the performance of a given system in a given acoustic...good room acoustics isn't an alternative to good DSP either. You need [emphasis added] both to maximize the sound quality.
This raises the questions: What is meant by maximizing the performance? What is meant by maximizing sound quality? What do you need DSP for in a good room? If it's just the psychoacoustic perception of more even response, that's one thing; but if it's a question of the actual behavior of the acoustical space, that's something else.
I can't speak for anyone other than me......... for me this means the polishing of whichever particular apple I have designed.

My designs are good - pretty good in fact - however I have not been able to achieve a "perfect" room.

In the "zone" (by which I mean the engineer's seat) I have been able to get rooms (strictly through room finishes) pretty darn flat........ for example Studio "H" at Hit Productions is flat with the exception of a 1dB dip around 80 Hz and a 1.5 dB spike around 100Hz...... Speakers are Barefoot MM27's... that is something that can be cleaned up with DSP (although probably have to live with the dip because I don't see dips getting solved without additional speakers to combat the problem)....... The "Zone" in this case is about 3' wide.

No it is not an issue of phychoacoustics - it is an issue of the room.......... I do not know anyone who has a room that is letter perfect...... there are too many pieces of the puzzle that are not in the control of the designer. Well perhaps Wes Lachot, he's pretty amazing - but he also has his own construction crew and builds out the studios he designs.....

When we built Power Station New England I was at the site every single day - start to finish - and I could physically take control of the entire operation - from layout to the fussiest prick you ever saw when it came to QC on the room finishes, I was there. If there was more than 1/16" variance in a slot from top to bottom it (the slat) was removed and replaced by the carpenters...... more than 1/4" accumulative on an entire wall and the same thing......... one time they took down almost 12' of wall (floor to ceiling almost 24' in that spot) because they screwed up when I was tied up with something else........

That level of scrutiny pays off - Tony B. was wild when he heard those rooms, but also (in all fairness) Tony designed them - I merely found a problem - fixed it - and then saw to it that his design was followed to near perfection (As near as is physically possible with wood construction).. Tony is a wild man - but he is also a friggen genius - that studio is a due to his genius - something I cannot claim for myself.........

However - I am not able to be all over the world - and thus I do not have that level of control anymore. A screw up of even a few degrees in layout can change quite a bit acoustically. So if A room comes out as good as +/- 1.5 dB I am quite happy...... and if DSP can provide the final polish, the Owner is VERY happy, which in turn makes me VERY happy - because their recommendations are indeed my bread and butter.......

That is the extent of my endorsement...........

Rod
Old 21st June 2010
  #125
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Rod:

Pretty cool that somebody is able to make a room down to that kind of specific detail.

What kind of gear do they use in that room?
Old 21st June 2010
  #126
SAC
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Quote:
Originally Posted by Midgard Audio View Post
SAC: Please cut down to 1/10.

When you use the term "superposition" (not 100% correctly since the source is the same) talking about direct and reflected sound makes me wonder why you at the same time tells us that dispersion does not affect this summation.
??? What???

Superposition is the combination - the 'summation' - of 2 or more signals. And all of the reflected energy derives from the direct source!

Reflections above the Schroeder critical frequency are specular. We are concerned with amplitudes and arrival times.

I have no idea what you are talking about with regards to a specular reflection's 'dispersion'. We don't care about their Q, except in that we control their spatial and temporal behavior with either absorption or diffusion. They are specular. If they superpose, that means the component signals occupy the same space. What is your point?

The time differential is what causes the destructive anomalies.

Quote:
Originally Posted by Midgard Audio View Post
That EQ-ing can not change time domain problems, remove modal nodes and such things has been mentioned several times already, no need to repeat that over and over. Noone seems to disagree.
You have got to be kidding, right? Read your sentence after next!

You statement is incorrect.

One CAN EQ minimum phase LF modes to a degree. Contrary to your statement above that says we "can not... remove modal nodes" and that "noone seems to disagree" - except perhaps yourself when you then assert the exact opposite: "The audible effect of moderating modal nodes with EQ is audibly positive."

We can't, we can, no one disagrees, yet you disagree within the same post.

Quote:
Originally Posted by Midgard Audio View Post
In a normal room there are always tendencies that shows in a wider field than just the half meter around the listener.
Huh???


Quote:
Originally Posted by Midgard Audio View Post
The audible effect of moderating modal nodes with EQ is audibly positive.



I have no clue as to what the actual substance is that you are actually trying to say.

Thus far you talk about EQ and controlling a direct sources dispersion without any specific context.
Fine. Controlling dispersion in order to control reflections can indeed be beneficial.

EQ is moderately useful in the control of LF modal peaks.
Other than that, EQ is essentially of little use or consequence in the context of the tuning of a room. Nor does EQ require DSP - the topic of the thread.

If one wants to discuss DSP for such uses as array steering, or pattern control for speakers, fine.
But thus far you have only mentioned that you can, and then that you can't, use EQ to moderate modal nodes.

But you have yet to relate any of this to DSP or "room tuning".

And nothing has been related to what we know regarding the time or frequency perspectives of bounded room behavior and the physics and psycho-acoustics of such behavior.

This subject as it is now being presented is utterly undefined and rambling and it lacks any nexus with small acoustical space behavior.

If you simply want to say that a well-behaved speaker polar pattern and flat power spectrum is of value - fine. If you want to say that EQ has "limited" use regarding the moderation of LF modal peals - fine.

But, other than that, I see this going nowhere else as neither acoustical principles nor DSP are being accurately presented, and Rod has stated what I think is a pretty fair assessment of the use of DSP with regards to 'room tuning'.
Old 21st June 2010
  #127
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Quote:
Originally Posted by Midgard Audio View Post
There are several methods. What they have in common is, as with the arrays, you need more than one driver for a certain frequency.
That is what I thought, more than one driver and introduce a time delay/phase shift in one

Quote:
Originally Posted by Midgard Audio View Post
BTW, why do you mix Q and dispersion pattern?
Because I'm not quite sure of the difference to be honest! I've be used to using the term directivity.....Q and dispersion are somewhat unknowns to me, comes down to terminology possibly
Old 21st June 2010
  #128
SAC
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Q and dispersion are not necessarily the same thing.

While Q and the directivity index are often related, on in terms of unit-less ratios and the other, a logarithmic relationship expressed in dB.

For instance, a speaker can have a Q of 2 A ratio of 'in to out'), yet feature a distinctive collapsing polar pattern with frequency. Thus they can compliment each other in the specific information provided.
Old 21st June 2010
  #129
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SAC:

You write like you are very angry.


Regarding superposition, it is no big deal. But a very important part of the principle is that the sources can be altered independently, and the room artifacts are derived from each of the two sources independently and then summizes.


If you consider a reflection as a separate source, the level at each frequency emitted from this "source" is still depending on the speakers output at the angle that meets this specific reflection. This way changing the speakers dispersion pattern will also change the reflections.


About EQ, I said:

You can not REMOVE modal nodes with EQ. I have never said you can and that is not my opinion either. However, EQ-ing is pretty effective on REDUCING THE AUDIBILITY of the nodes. That does not mean it is not better to remove them, but a normal listener would not be able to tell if there are difficult room nodes there until he has hear them completely removed.

When I write about audibility, it is all about psychoacoustics, not about technical terms.


When I say "please reduce to 1/10", I mean, that you should be perfectly able to make your points writing a fraction of what you are currently writing. You could spend the rest of the time reading with a bit more precision.
Old 21st June 2010
  #130
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Quote:
Originally Posted by Dange View Post
That is what I thought, more than one driver and introduce a time delay/phase shift in one
Yes, or you could process it a bit more complex than that, but still it is very much the same thing.

Quote:
Originally Posted by Dange View Post
Because I'm not quite sure of the difference to be honest! I've be used to using the term directivity.....Q and dispersion are somewhat unknowns to me, comes down to terminology possibly
In Norwegian Q is referred to as "the goodness factor" (it is a very bad translation of the not much better expression "quality factor). Noone seems to understand what that means heh The easiest way to understand Q is to use the expression "Q is the ability to resonate".

If you look at an LCR-chain of passive components, it is pretty easy to determine a quite clean value for Q. In other situations, Q is a bit harder to determine precisely.

If you look at a parametric EQ, Q is defined as the divider for frequency when determining bandwidth. An EQ point at 1kHz with Q=0,5 normally means a bandwidth of 2kHz (there are some different definitions here as well). This is more or less indipendent of the level at which you EQ. In the passive components example, the level would connect directly to the Q value.

This difference is simply because Q tells us different things depending on where we use it within the same circuit.

Example:
If you use a woofer/BR-enclosure combination that gives a very smooth and soft roll off, Q is beyond doubt very low (this is the Qb, the Q value for the driver/enclosure-combo. The driver Q is mathematically a part of this equation, but Qb does not directly tell us anything about the driver Q). If you tune the driver so that it rolls off with a sharp edge at the resonance frequency (Fb) the Q is high.

However, this normally means that the level at Fb is much higher too. But if you increase the cabinet volume and reduce Fb, you will still get a very sharp roll off edge, but the level at Fb is now reduced. If you determine Q based on the sharpness of the edge, it will turn out pretty high. If you determine Q based on the level at Fb compared with the reference level at 200Hz or higher, the Q will turn out pretty low.

So throwing Q around without further definition is not very useful.




If you look at a PEQ band, decreasing the Q value should be the same as increasing the dispersion of this band in the frequency domain.




Dispersion pattern, at least what I have been talking about, is the polar plot of a loudspeaker, both vertically and horizontally.

If you put a loudspeaker in an anechoic chamber on a controlled turntable, you can measure the on axis response, then turn the speaker a few degrees, measure the first off axis response, turn a bit more, measure again and continue like this until you have mapped the entire 180 or 360 degrees around the speaker. That is what I am refering to as the dispersion pattern, polar response or energy response.



Dispersion pattern = all the info about the speakers on and off axis behaviour.

Polar response = frequency specific single plane response. However, it is quite usual to put the vertical polar response in one half of the diagram and the horizontal response in the other half.

Spectrum polar response = a version of polar response covering all frequencies by showing level as colour and angle/frequency on the X and Y axis.

Energy response = the sum of all on and off axis measurements plotted in the frequency domain showing the total amount of energy the speaker emits at each frequency.



EDIT: I see that SAC has brought directivity Q into this as well. I guess that answers my question of why you mix it with dispersion. When working with Q in room acoustics, I normally think of room nodes.

It is an old way to express directivity that very much looks like an EQ if you use the X axis as angle and the Y axis as level. The peak you get is the "eq point" and the X axis always have the same extent as the frequency which is being analysed.

The problem with using this is loobing. It very seldom adds up precisely to real life situations and is therefore pretty unuseful. The last 30-40 years it has been completely replaced by polar plots, and later, spectrum polar plots.
Old 21st June 2010
  #131
SAC
Registered User
 

Angry? Are you kidding? I am caught between laughing and being frustrated as I once had the notion that words meant something and that, at some point, a coherent discussion of acoustics might occur.

So, after how many pages, the topic has devolved to what is “Q”, what is "directivity", and what is "dispersion". Oh, and let’s not forget “You cannot REMOVE modal nodes with EQ. I have never said you can and that is not my opinion either. However, EQ-ing is pretty effective on REDUCING THE AUDIBILITY of the nodes. That does not mean it is not better to remove them, but a normal listener would not be able to tell if there are difficult room nodes there until he has hear them completely removed.” and “When working with Q in room acoustics, I normally think of room nodes.”

And let’s not forget that some have questioned the ‘meaning’ of what constitutes “superposition”.

And all of this is in addition to what characterizes a reflection.

All of this is fascinating. Not necessarily productive, but fascinating. This thread has devolved into folks redefining basic terms used throughout the engineering and physics world that I had once thought were pretty well understood. Granted, some may not be familiar with them, but the problem was not for a lack of defined meaning!

So, from what (little) I can tell, EQ can or cannot do some stuff that has something to do with “dispersion” that effects reflections that may or may not be dependent upon a direct signal (and the nature of the resulting reflected signal having been subsequently modified via impact with a boundary of a particular acoustic impedance).

OK.

I had once thought that the state of acoustics was such that we ‘pretty much’ understand the mechanics of small acoustic space behavior. But then I once thought that acoustics addressed phenomena that was defined in a fairly objective manner.

But for a thread that started out being about one’s “opinion” about “room correction software” we have devolved to “what is Q” and What is dispersion”… or “directivity” or “what is a polar plot?”

All we are missing is “what is sound?” and “how do we know if we are experiencing it?”

And this is where all should be reading Hume lest they mistakenly accept anything they may have wasted their time learning in engineering or physics.

What we lack here is a common basis regarding current models of acoustic behavior (such as presented in a standard text aka the mid 1980s, such as Sound System Engineering, by Davis and Davis). What we don't need is yet another subjective philosophy of what constitutes the 'science' (yeah, right!) of acoustics!

Far from being a discussion that reflects (sorry, but at least we get to finally use what ‘sounds’ like an acoustic term) the current understanding of small acoustical space acoustics behavior integrating our current understanding of psycho acoustics, I defy anyone to accurately describe exactly what is “acoustically” being discussed!

And what is comical is that anyone would suppose that “DSP” were necessary to do anything other than to further obscure the basic understanding of acoustics that has all but gone missing in this thread.

But I will assert that the title of the thread is appropriate. It is about “opinion”, as any hope of the discussion of acoustics based upon objective standards, methods, or analysis relating in any way, shape, or form to perspectives defined in the B&K Domain map is apparently hopeless.

And if anything has become apparent, it is that the "effectiveness of room correction software" is indeed subjective, as the proponents have not yet posited a coherent account of what they imagine 'occurring' in the phenomenal world, let alone how such software might modify it in an objectively verifiable manner.

The problem with that is that for software to be properly designed, one must have a VERY good grasp of acoustics. As all follows from an exceptional conceptual grasp of what is happening and an exceptional grasp to be able to evaluate the phenomenal world for events, and then to manipulate said events in a productive manner that actually results in a real improvement, and not simply something 'different" And such results can be objectively and subjectively verified. But when the fundamental problem is that one cannot even remotely address - or simply regurgitate an accepted reference source! - why would one expect the result to be any more complete or accurate than the ill formed question?

As has been stated earlier: This thread is done. That is, unless others want to discuss their “opinion” of what “done” means….

And I suspect that perhaps someone somewhere is still wondering just when or where "DSP" or even "software" enters the picture! Heck, I am left wondering just where "acoustics" enters the discussion. Tell me there isn't a more than adequate basis for laughter!
Old 21st June 2010
  #132
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If room correction is such total failure which SAC gives an impression of I'm wondering why it came out so good in Harman Int. blindtest? There were only one DSP that gave a worse result then no correction and I believe that was Audessey.
Audio Musings by Sean Olive: The Subjective and Objective Evaluation of Room Correction Products

And what about the room where the test took place? It's treated with more acoustic treatment then most people are able to have in their living room.

Audio Musings by Sean Olive: The Harman International Reference Listening Room

I believe what juicehifi has said is right; The acousticans who will combine acoustic treatment with room correction will succeed more then others.

SAC:
Would be interesting to know what experience you have with sound correction. Have you actually listened to any setups with advanced DSP? I'm not talking about Audessey or other crappy softwares that comes with surround receivers.

And yes, you're writing in a angry and very impolite matter.
Old 21st June 2010
  #133
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Quote:
Originally Posted by bwo View Post
If room correction is such total failure which SAC gives an impression of I'm wondering why it came out so good in Harman Int. blindtest? There were only one DSP that gave a worse result then no correction and I believe that was Audessey.

Audio Musings by Sean Olive: The Subjective and Objective Evaluation of Room Correction Products

And what about the room where the test took place? It's treated with more acoustic treatment then most people are able to have in their living room.


Audio Musings by Sean Olive: The Harman International Reference Listening Room
BWO,

With all due respect,

Everything (in this test) began with a properly treated room....... with adjustable room acoustics so that they could (in fact) make room adjustments for different conditions.

So you are now back to the point that I have been making all along in this thread - which is also the point being made (much more eloquently) by SAC - which is not that DSP doesn't have it's place - but rather that it is not the "CURE ALL" that some are making it out to be. Just for the record - and I read through his posts twice just to be sure - but SAC has no once taken the position or made the suggestion that "room correction is such total failure" - he has only stated that it is over-hyped....... which is a totally different colored horse.

Quote:
I believe what juicehifi has said is right; The acousticans who will combine acoustic treatment with room correction will succeed more then others.
I would submit that all things considered - any room within +/- 1.5 dB of flat is good enough to stand on it's own merit........ my position is that there is nothing stopping a designer from coming up with rooms that are very near perfect acoustically (ever perfect acoustically) - at which time there is then icing on the cake which may be desired by some - although others may well opt to save their money and use the room as is...... and with excellent results.

Power Station New England is not using DSP correction for their control room, and Tony's "A" room is one of the more famous rooms in the world - There is currently no DSP correction in Studio "H" at Hit Prooductions (the room I spoke of earlier).

Dark Pine Studios is not using DSP correction (another of my studios).

And in all 3 of those studios people are amazed by the sound in the control room even when it is played back without EQ

Remember - some of the best music in the world was recorded and engineered in rooms that never had the benefit of DSP.......

By the way - the 3 grand a pair speakers and the equipment they are running the sound through also play a big part in this - something not usually rivaled in home systems - or even in small recording studios.......

Quote:
And yes, you're writing in a angry and very impolite matter.
I have read, and then re-read the posts made by SAC (by the way - just for the record - other than running across his posts in here I do not personally know the person - thus I have no vested interest in defending him) and I find that his posts portray an increasing frustration at the direction of the thread and what he sees as evasion rather than a direct specific response to his pointed questions - based in science.

What I do not see is anger.....

There is certainly a difference between the 2.........

Sincerely,

Rod
Old 21st June 2010
  #134
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Quote:
Originally Posted by Rod Gervais View Post
BWO,

With all due respect,

Everything (in this test) began with a properly treated room....... with adjustable room acoustics so that they could (in fact) make room adjustments for different conditions.

So you are now back to the point that I have been making all along in this thread - which is also the point being made (much more eloquently) by SAC - which is not that DSP doesn't have it's place - but rather that it is not the "CURE ALL" that some are making it out to be.
I haven't seen anyone stating in this thread that DSP is a "cure all" remedy. On the contrary, everyone is saying that the room should be treated physically first.
Quote:
Originally Posted by Rod Gervais View Post
Just for the record - and I read through his posts twice just to be sure - but SAC has no once taken the position or made the suggestion that "room correction is such total failure" - he has only stated that it is over-hyped....... which is a totally different colored horse.
Well, then I need to apologize. I find it a bit hard to follow SAC in everything he's saying. I got the impression from his posts that DSP doesn't really work.


Quote:
Originally Posted by Rod Gervais View Post
I would submit that all things considered - any room within +/- 1.5 dB of flat is good enough to stand on it's own merit........ my position is that there is nothing stopping a designer from coming up with rooms that are very near perfect acoustically (ever perfect acoustically) - at which time there is then icing on the cake which may be desired by some - although others may well opt to save their money and use the room as is...... and with excellent results.

Power Station New England is not using DSP correction for their control room, and Tony's "A" room is one of the more famous rooms in the world - There is currently no DSP correction in Studio "H" at Hit Prooductions (the room I spoke of earlier).

Dark Pine Studios is not using DSP correction (another of my studios).

And in all 3 of those studios people are amazed by the sound in the control room even when it is played back without EQ

Remember - some of the best music in the world was recorded and engineered in rooms that never had the benefit of DSP.......

By the way - the 3 grand a pair speakers and the equipment they are running the sound through also play a big part in this - something not usually rivaled in home systems - or even in small recording studios.......
Rod. My point of view is listening rooms and not studios. Sure, if you have the ability to build a room from scratch and a have an unlimited budget and no considerations for WAF, I don't doubt that it's possible to build an excellent sounding room without DSP. I personally have yet to hear a room like that. I been in some well treated rooms and in my opinion they all would benefit from DSP. And for most listening rooms which are in living rooms where the possibility of acoustic treatment are often somewhat limited and the dimensions of the room are far from optimal, the use of DSP (from the listening experience I've today) seems very beneficial. But not only living rooms. I would say the same thing for the studios I've visited. None of these studios are in the league you're mentioning. They were well treated, but still the frequency response had some obvious flaws. So my experience is that very many systems out there, both studios and listening environments, need DSP to flatten out the frequency response. Ethan Winer has over 50 bass traps in his listening room and still uses EQ for the bass. And from seeing pictures of his room, I would say he has a better dimensioned room that very many people have. For most rooms, the frequency response will be worse then his.

It's important thought that DSP is implented correctly. I've heard systems with DSP I disliked. It seems to depend on the "chef" and also the DSP software.
We also need to remember that really good DSP software has quite recently arrived. And it's also still in development. Who knows, maybe some of these studios you're mentioning will be using DSP in the future. But perhaps they don't need it. But from my standpoint, where the possibilty for most people building rooms that are almost flat isn't an option, DSP isn't only welcome but also very much needed if the sound is going to be very good.
Old 22nd June 2010
  #135
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Quote:
Originally Posted by Rod Gervais View Post
So you are now back to the point that I have been making all along in this thread - which is also the point being made (much more eloquently) by SAC - which is not that DSP doesn't have it's place - but rather that it is not the "CURE ALL" that some are making it out to be. Just for the record - and I read through his posts twice just to be sure - but SAC has no once taken the position or made the suggestion that "room correction is such total failure" - he has only stated that it is over-hyped....... which is a totally different colored horse.
I have not seen this "cure all"-statement either, where is it?

Quote:
Originally Posted by Rod Gervais View Post
I would submit that all things considered - any room within +/- 1.5 dB of flat is good enough to stand on it's own merit
Isn't that a bit like the good old "all that can be invented is now invented"-statement?

Quote:
Originally Posted by Rod Gervais View Post
I have read, and then re-read the posts made by SAC (by the way - just for the record - other than running across his posts in here I do not personally know the person - thus I have no vested interest in defending him) and I find that his posts portray an increasing frustration at the direction of the thread and what he sees as evasion rather than a direct specific response to his pointed questions - based in science.

What I do not see is anger.....

There is certainly a difference between the 2.........
The problem as I see it is that when someone writes something, and SAC adds a opinions to him and follows up with personal attacks.

If there are some unanswered questions here I am not aware of them, please quote them.
Old 22nd June 2010
  #136
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Quote:
Originally Posted by Midgard Audio View Post
I have not seen this "cure all"-statement either, where is it?
on about every marketing text for "room correction software" i have seen!
Old 22nd June 2010
  #137
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Rod Gervais's Avatar
 

Quote:
Originally Posted by bwo View Post
I haven't seen anyone stating in this thread that DSP is a "cure all" remedy. On the contrary, everyone is saying that the room should be treated physically first.
BWO,

When I made that reference I was not speaking about this thread in particular - I was speaking about salesmen pushing the product in general...... although I am aware that some people in the sales force have scruples - the majority I have met will say pretty much anything to make a sale...... and there are salespeople out there saying that this is the best going.....

Quote:
Well, then I need to apologize. I find it a bit hard to follow SAC in everything he's saying. I got the impression from his posts that DSP doesn't really work.
He never said that - in fact he said quite the opposite - in fact he the following:

Quote:
Bottomline, DSP can indeed do some very interesting and useful things.
Rod
Old 22nd June 2010
  #138
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Quote:
Originally Posted by gigi View Post
on about every marketing text for "room correction software" i have seen!
...in this thread.
Old 22nd June 2010
  #139
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Quote:
Originally Posted by Ethan Winer View Post
Excellent, thanks for chiming in.



This is all true, with one really important caveat - the more correction you apply with DSP, the smaller the physical area you can correct will be.

--Ethan

________________
The Acoustic Treatment Experts
That is to a certain extent true for time domain correction. And the more time domain correction you do the less the sweet spot will be. But it usually sounds far better outside the sweet spot than most acousticians seem to believe heh

With a pure frequency correction the size of the sweet spot will basically be the same. But since the speaker problems from ca 500 Hz and up, and the most dominant bass problems are global you can usually get significantly better sound in all seats.
Old 22nd June 2010
  #140
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Quote:
Originally Posted by SAC View Post
The really humorous reality is that we lack systems that can reliably simply and accurately EQ complex spatial and time variant systems!
In case you haven't understood what a (basically) time invariate system is: It is a system that measures & sounds the same way next friday as it did last tuesday. If that assumption doesn't hold for practical purposes we are all in deep ****.
Old 22nd June 2010
  #141
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Midgard Audio View Post

Quote:
Isn't that a bit like the good old "all that can be invented is now invented"-statement?

First let me preface what I am about to say with the fact that I am a person who is ALWAYS on the cutting edge of industry - not only do I embrace new ideas - I have also been chosen (due to this) to act as part of a jury in a very serious examination of parties with new and exciting ideas within the steel industry to help determine which of them should receive funding from the industry to further develop their ideas...... So I am not a person opposed to new inventions...

That having been said - let's look at this realistically for a moment.....

Seeing as the human ear does not work well discerning low frequencies (hence the EQ Smile) correcting a 1.5 dB spike would not mean a whole lot in a room - in fact it's a very minute correction - and as far as the 1 dB dip goes - you are not correcting that at all through the use of the original speakers - inverse signals or not - I don't care how you process the data - when the problem is being caused by an inverse signal to begin with - adding that to the chain will (at best) maintain the status quo - boosting the signal will not solve the problem either - as it will only increase the dip proportionately to the added signal.

SO we are talking about someone investing hundreds of dollars just to correct for a 1.5 dB peak.....

Once they know this is what's taking place they could just step outside of the recording chain and deal with that using standard PEQ........

And if the discussion is about the room in general - (just for the record) even in the very back of the room (at the producer's couch) the mids and highs are flat across the board - the lows have some fluctuations - but they too are relatively small - +/- 3 dB.......... and I cannot for the life of me figure out how you deal with that without changing the sound at the engineers sweet spot.....

So for now, (in my rooms at least) I do not see why this would be a desirable element in the listening chain.

This is not to say that I do not believe it has it's place....... as I noted earlier - I am very impressed with the noise control systems being used in some automobiles today - how they handle outside noise entering the vehicle through the use of DSP and inverse signal transmissions - although (as I also pointed out) they have fairly tight sweet spots for the driver and passengers (in fact some can only handle the front seat passengers).

Do I want to see research or development on these systems stop?

Certainly not !!

Do I believe that these systems have reached the peak of their developmental abilities?

Not for a moment.

I believe completely that there will come a time where there can be more done with DSP than is being done now - pretty much the same as with all technology.....

And do I know for a fact that there are engineers out there who are being honest about both the capabilities and limitations of their products?

Absolutely - in fact I have a lot of respect for the ones who do.


Quote:
The problem as I see it is that when someone writes something, and SAC adds a opinions to him and follows up with personal attacks.

If there are some unanswered questions here I am not aware of them, please quote them.
Perhaps SAC will sit and make a complete list of them - perhaps not - I was not speaking of my read of this thread - I was merely read what the man wrote - with no bias in any direction - and voicing my view of that......

I would certainly never presume to speak for the man - in this regard I am just an observer (heck - I have enough of a problem figuring out what I am saying ans what the responses to that mean - never MIND getting involved for someone else).........

Regards,

Rod
Old 22nd June 2010
  #142
Lives for gear
 
Rod Gervais's Avatar
 

Quote:
Originally Posted by Midgard Audio View Post
Rod:

Pretty cool that somebody is able to make a room down to that kind of specific detail.

What kind of gear do they use in that room?
Midgard,

With the exception of the the largest Pro Tools HD workstation in the country (which includes a 24-fader ICON D-Command mixing surface) and the speakers noted above - I really couldn't tell you what is in the rest of their chain - not a clue.

Sorry I can't help with that - I am well aware that great gear inside a great room = great sound...... but that information is outside of my need to know.... not that Dennis Cham wouldn't tell me - just that I don't really need to know all of that as a part of my room design......

Regards,

Rod
Old 22nd June 2010
  #143
This thread seems to be breaking down. I'm going to close it, but if it turns out it was stopped prematurely (and can get back on track), message me and it can be reopened.
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