agent.5 said:
There is such a thing as over-equalization - in this case, all I plan to do is remove peaks from the response. 2 or 3 parametric EQs should be plenty - the few times I twiddled with a parametric EQ, 2 sections usually got rid of the worst peaks. A room would have to be pretty bad to need 3 peaks removed in the narrow 80 to 240 Hz range - bad enough that room treatments might be a better approach.
My attitude towards holes in the response is "live with it", or at worst, do something about the room. Dumping energy into a room null is a bad idea all around - it wastes power, greatly increases driver excursion (really bad), and still sounds weird and "pressurized" when it measures flat.
Channel-by-channel peak removal works pretty well, though, clarifying the bass region wonderfully. The improvement in the stereo image is also quite noticeable and appreciated.
Some Good Papers from Meyersound
Can Line Arrays Form Cylindrical Waves?
Beam Steering with Time Delays
HF Driver Design
Can Line Arrays Form Cylindrical Waves?
Beam Steering with Time Delays
HF Driver Design
Flat
Some yeas ago I remember reading of a mfg using very high quality and great sounding speakers built a 3-way system.
The crossover was passive with the very best parts, soft and hardware available at the time.
It was massively complex.
They got it flat to 0.5dB.
Bottom line it sounded like s***.
Zene
Some yeas ago I remember reading of a mfg using very high quality and great sounding speakers built a 3-way system.
The crossover was passive with the very best parts, soft and hardware available at the time.
It was massively complex.
They got it flat to 0.5dB.
Bottom line it sounded like s***.
Zene
KBK said:
It depends where you do the correction. From 200~300 Hz on up, the ear can distinguish between the direct-arrival spectra and the spectra of the room reflections. The microphone is too stupid to do this, and sums them all together.
There's still some controversy over this, but most speaker designers optimize the direct-arrival spectra, since the consensus opinion (with a few noisy dissenters) is that first-arrival spectra determines the sonic "color" of the speaker, with the room playing a secondary role.
With nearly all speakers, the room energy diverges to at least some degree from the first-arrival spectra, with the room energy tending to roll off at higher frequencies. You can see where this is going. If you mindlessly equalize the combined spectra from the direct-arrival + room spectra, the direct-arrival will be "hot". That's why the prosound folks so commonly build in a HF rolloff starting around 3 kHz.
I'm old-school enough to aim for a subjectively pleasing direct-arrival spectra (slight bass lift) and trying to get the room spectra fairly close to that. This is the traditional BBC method, and I'm sticking to it. It works for symphonic music, and sounds good on rock, too.
Now for frequencies below 200~300 Hz, the wavelengths are getting so large they are starting to merge with room modes, making them difficult to isolate. This is where EQ makes sense - the distinction between direct-arrival and total room energy disappears at these frequencies.
So I believe in limited EQ - below 300 Hz, and only to remove the biggest peaks on a per-channel basis. The same EQ compensation should NOT be applied to both channels! One of the biggest benefits of individual per-channel EQ is the ability to get rid of the worst LF channel imbalances - so speakers can be located for best image quality, and not be as constrained by avoiding LF artifacts.
The EQ addicts just slam everything through the auto-EQ, and of course that gums up the direct-arrival sound, wrecking the frequency response and making a mess of the time coherence. When I apply the auto-EQ from my Denon HT receiver, I have to undo more than half the EQ - basically everything above 300 Hz.
So I take a purist approach above 300 Hz, designing the passive crossover and the drivers to have an intrinsically flat first-arrival response, and with as good a time coherence as I can achieve. Below that, modest active EQ works fine, and transistor amps don't sound too bad either.
Wally Malewicz of WallyTractor fame has designed his own speakers, which he sells on a custom basis. He takes the same approach, using a Fane parametric EQ for the bi-amped bass modules, and using a passive crossover for the mids and highs. I spent a very enjoyable couple of hours at the last RMAF chatting with him, and I can tell you he's a very sharp guy, and knows what he's talking about. His speakers are first-rate and very musically balanced, in the Siegfried Linkwitz class.
Just to close out my previous posts I want to say a couple of things.
First, I am not claiming to be right and others wrong about anything (not in these last posts at least), I am only asking that those who are making the claims support them with scientific data.
Clearly this is not a position that one can hold in this forum as was so clearly pointed out ("swimming upstream")
As a scientist, I have no business in discussions where the scientifc method is not held as the only viable road to truth. To me a subjective test that is done without scientific controls and statistical analysis of the results is no test at all. The fact that the reported results of such tests are often self serving to the discussion makes them even more suspect in my eyes.
I simply cannot have a discussion where there is no coaberating evidence and/or the data is so loosely obtained. Others feel perfectly comfortable with that situation, I am not. So I will leave these types of discussion to those who enjoy them.
First, I am not claiming to be right and others wrong about anything (not in these last posts at least), I am only asking that those who are making the claims support them with scientific data.
Clearly this is not a position that one can hold in this forum as was so clearly pointed out ("swimming upstream")
As a scientist, I have no business in discussions where the scientifc method is not held as the only viable road to truth. To me a subjective test that is done without scientific controls and statistical analysis of the results is no test at all. The fact that the reported results of such tests are often self serving to the discussion makes them even more suspect in my eyes.
I simply cannot have a discussion where there is no coaberating evidence and/or the data is so loosely obtained. Others feel perfectly comfortable with that situation, I am not. So I will leave these types of discussion to those who enjoy them.
From the ALMA webpage:
"Earl Geddes has been in the audio industry for nearly 40 years. He holds a BS and MS in Physics from Eastern Michigan University and a PhD in Acoustics from Penn State. He has worked in audio his entire life, mostly with Ford Motor Company but later at Knowles Electronics, always in the area of audio transducers and systems. Dr. Geddes has received numerous scholarly awards, more than 25 patents, and he has authored two books. Earl is currently President of GedLee LLC a consulting firm in Acoustics that he runs with his wife, and this year he joined up with Kenny Jackel to start Audio Intelligence (Ai), a loudspeaker manufacturing company located in Bangkok, Thailand. He has been a very active AES member since 1978, and an ALMA member since 1999."
Meanwhile, back at the Hogwarts School of Magic and diyAcoustics, Magnetar made an interesting post:
15" + CD/horn systems trace their lineage back to the 1937 Iconic - it has become the sound we recognize as the "studio monitor", since so many have followed that format. Drivers come and go, horns and compression drivers change, but the basic format is now in it's 70th birthday.
Magnetar, what's your take on the cohesion issue? Do you think the combination of CD's and midbass drivers are doomed to fail, or maybe the transition to direct radiators needs to be deferred to much lower frequencies where horns become unreasonably big? Just curious about your take on the whole Iconic/studio-monitor format for loudspeakers.
Having been properly put in my place by a senior scientist at Ford Motor Company and Knowles Electronics, I'll put on my wizard's cap and ask the other magicians here what they think of the subjective-integration issue. Dissimilar driver technologies, working at the ends of their ranges? Trouble with changes in radiation pattern at the crossover frequency? Wrong choice of crossover frequency? Lack of scientifically-controlled double-blind testing with an objective test panel of listeners using a statistically-valid methodology?
Not that I'll be taking anyone's advice, mind you. I'm slowly writing my own book of spells, and as the good Doctor has so thoughtfully reminded me, I have a great deal to learn yet.
"Earl Geddes has been in the audio industry for nearly 40 years. He holds a BS and MS in Physics from Eastern Michigan University and a PhD in Acoustics from Penn State. He has worked in audio his entire life, mostly with Ford Motor Company but later at Knowles Electronics, always in the area of audio transducers and systems. Dr. Geddes has received numerous scholarly awards, more than 25 patents, and he has authored two books. Earl is currently President of GedLee LLC a consulting firm in Acoustics that he runs with his wife, and this year he joined up with Kenny Jackel to start Audio Intelligence (Ai), a loudspeaker manufacturing company located in Bangkok, Thailand. He has been a very active AES member since 1978, and an ALMA member since 1999."
Meanwhile, back at the Hogwarts School of Magic and diyAcoustics, Magnetar made an interesting post:
Magnetar said:
15" + CD/horn systems trace their lineage back to the 1937 Iconic - it has become the sound we recognize as the "studio monitor", since so many have followed that format. Drivers come and go, horns and compression drivers change, but the basic format is now in it's 70th birthday.
Magnetar, what's your take on the cohesion issue? Do you think the combination of CD's and midbass drivers are doomed to fail, or maybe the transition to direct radiators needs to be deferred to much lower frequencies where horns become unreasonably big? Just curious about your take on the whole Iconic/studio-monitor format for loudspeakers.
Having been properly put in my place by a senior scientist at Ford Motor Company and Knowles Electronics, I'll put on my wizard's cap and ask the other magicians here what they think of the subjective-integration issue. Dissimilar driver technologies, working at the ends of their ranges? Trouble with changes in radiation pattern at the crossover frequency? Wrong choice of crossover frequency? Lack of scientifically-controlled double-blind testing with an objective test panel of listeners using a statistically-valid methodology?
Not that I'll be taking anyone's advice, mind you. I'm slowly writing my own book of spells, and as the good Doctor has so thoughtfully reminded me, I have a great deal to learn yet.
gedlee said:
Just be aware that the origins of the scientific method lie with Robert Hooke, Boyle, etc..and have nothing to do with the current norm as created by Newton, whom was someone who crushed Hooke and rebuilt the Royal society to his own desires. One of which was was to re-define 'scientific' methodology' to HIS particular 'way'. This actually made technological change and advance less occurant and less viable. Interesting stuff happened way back then. hhhmmmmm
Like Newton's ego, for example. Ie, the idea of his math making reality, instead of the utterly realistic and sensible..other way around. Which the true origins of 'the scientific method' - is, and was, predicated upon.As co-author of the pre-eminent reference document on the subject of audio transducers extant, ( no less than two respected experts in the field attest on the internet) , how can there be any bias?
It's unfortunate that many of us will simply never catch up to this level of understanding.
For a more scientific forum, I recommend the High-Efficiency Speaker Asylum, where EG normally posts. Use the search engine, and you can find all of the relevant posts there.
Lynn Olson said:
And THAT is pretty much the point of an internet forum, be it diyAudio, an AA board, HTguide, etc..
An exchange of ideas that *might* lead somewhere.Take some info (good or bad), mull it over and THEN (if interested) test it out for yourself in a manner you deem worthy. Or conversely, give some info and see if others do similarly. Hoping in either case that it gives someone some benefit - and a
.It hasn't been, and likely never will be, an exchange of control tested data to prove (or disprove) a hypothesis. (It would be sweet though if we all had ready access to Klippel equipment and it could offer this functionality.
)I did a limited search - there appears to be no AES internet forum (..that might stand a chance of meeting such a requirement). Perhaps Earl could add founder of AES internet forum to his distinguished career?
Earl,
I don't think very many here would attack your theories or intellectual explorations. After all, they have been incredibly kind to me and my somewhat out of the mainstream ideas.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399
I for one would be delighted to read about your wildest surmises, to say nothing of your proven applications.
If someone attacks you, we will just get the moderators to smack them for us. They are really very good about not allowing anything but polite investigations. The reason most of us post here, really.
Bud
I don't think very many here would attack your theories or intellectual explorations. After all, they have been incredibly kind to me and my somewhat out of the mainstream ideas.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399
I for one would be delighted to read about your wildest surmises, to say nothing of your proven applications.
If someone attacks you, we will just get the moderators to smack them for us. They are really very good about not allowing anything but polite investigations. The reason most of us post here, really.
Bud
It is easy to take shots at Earl Geddes on the audio forums. I have seen him come and go on a few and it always seems to follow the same pattern. Basically he is driven off by a handful of audio wannabees attacking serious engineering work with personal opinions argued as facts. People don't like his style of posting and the mob of angry villagers quickly forms to storm the castle and get the monster. I can easily understand his reluctance to post on forums and exposing himself to the aggravation and waste of his time, he is not alone when you consider other people in the audio field that you would love to see discussing these topics on forums but they never appear.
The bottom line is he knows what he is talking about and if you compare the content and quality of the information in his book to the sum total of information posted by any individual on any forum there are not many people who can measure up myself included. I own his book, have read it many times, understand most of it, and use it often for a valuable reference as I think about my own designs and calculation methods.
One other interesting observation about this particular thread, in my opinion there is a lot of talking and throwing out of ideas but not much engineering taking place. This appears to be a holistic design based on subjective opinions, conjecture and trial an error evolution and not at all on basic OB engineering design principles. This is easily demonstrated by reviewing who is contributing and who is not, there are not many posts from the people working on OB engineering and design methods. There is not much presented in the thread for the engineering people to become interested in discussing and participating. Basically this thread is ony getting one side of the exchange of ideas, the engineering technical side is missing.
My opinions
Martin
Basically your right, I have no interest in arguing on web forum. I would be interested in teaching, but this is never taken for what its worth and is always met with an argument, followed by anger (if I don't agree) and then the personal attacks start.
I was once accused of "lecturing" on one of these sites - as if that was a bad thing!! I had always thought that the honor of attending the lecture of an expert was a good thing.
I don't deny being arrogant or even egotistical, but I do object to being treated without respect as I think that I have at least earned SOME respect in the audio community.
And you are right on the money when you point out that virtually none of the real experts in this field ever show up at these things. Floyd Toole once commented to me that I must be crazy to subject myself to these sites. I cannot imagine anyone being disrespectful to Dr. Toole, but yet it appears to have happened.
Basically your right, I have no interest in arguing on web forum. I would be interested in teaching, but this is never taken for what its worth and is always met with an argument, followed by anger (if I don't agree) and then the personal attacks start.
I was once accused of "lecturing" on one of these sites - as if that was a bad thing!! I had always thought that the honor of attending the lecture of an expert was a good thing.
I don't deny being arrogant or even egotistical, but I do object to being treated without respect as I think that I have at least earned SOME respect in the audio community.
And you are right on the money when you point out that virtually none of the real experts in this field ever show up at these things. Floyd Toole once commented to me that I must be crazy to subject myself to these sites. I cannot imagine anyone being disrespectful to Dr. Toole, but yet it appears to have happened.
Teh said:
You might find this both fun and interesting.
Honk Your Horn Thread.
I hope to get some others here to try it and comment.