Depending on where the original recordings are done, the recording polarity will differ. Some multi-mic recordings even have different polarity on different instruments. This creates a BIG problem. The whole relation between instruments and recorded room acoustics become wrong. 80% of audio system demos are conducted in the wrong polarity.
So there are so many issues related with audio reproduction we have not control of, the only thing we can do is use our best engineering judgement during design stage.
So there are so many issues related with audio reproduction we have not control of, the only thing we can do is use our best engineering judgement during design stage.
It is no problem to build a preamp with a polarity switch. Part of the hobby is finding well recorded material anyway. A good analog equalizer can be usefull too. For some time i used the Cello Palette to good advantage that had a polarity switch and a mono switch too but then i got lazy again. Noverdays i accept what is on the record and choose my music fitting to my mood.
Yes, from a user point of view, not everyone will have the same preference. From a designer point of view, we must design to a known preference. For example, the speakers in my avatar were designed for listening distance of 1~3M, however, there was a target cost involved. Since there was no development budget limit and no time constrant, the focus was how to meet the cost limit with a performance for best reproduction of music in this category. Listening test is a very important part of the effort. The most important part of listening test was for the listeners to describe what they found wrong, and it was discovered that many people focus on different aspects when they evaluate audio products. So what is important, is to see if the same audible deffeciencies can be allocated to specific measurement performance, then figure out how to technically solve the problem.
Stored energy is probably the biggest problem in most drivers. However, if we only focus on solving the stored energy problem, it's possible to end up losing low level background sound in the recording which is also a very important for reproducing the sensation at the original recording site.
Driver self diffraction would come as a close second biggest problem in near field designs. Basically, this is solved by using the smallest driver for the frequency range and maximum SPL desired.
Enclosure diffraction comes in third.
Talking about equalizers, I think the Ultimate Equalizer from Bodzio software might be worth keeping track of. Although no mature enough at the moment, but the goal is certainly very impressive.
Stored energy is probably the biggest problem in most drivers. However, if we only focus on solving the stored energy problem, it's possible to end up losing low level background sound in the recording which is also a very important for reproducing the sensation at the original recording site.
Driver self diffraction would come as a close second biggest problem in near field designs. Basically, this is solved by using the smallest driver for the frequency range and maximum SPL desired.
Enclosure diffraction comes in third.
Talking about equalizers, I think the Ultimate Equalizer from Bodzio software might be worth keeping track of. Although no mature enough at the moment, but the goal is certainly very impressive.
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Here is a partial picture taken from our web site.
The journey is a long story, but the main improvements were in the drivers.
As you can see, the driver has some slashes on it. Why is it there? The main puspose was to improve the breakup mode just above 20KHz. It also turned out that it improves dissipation of stored energy in other frequencies as well. How was it determined that this breakup mode was causing the problem? I was listeing to Mr. Domingo's singing, and at very specific notes, the image focus would be lost, and the note sounded very harsh. So we looked at the data and it seemed the only possible cause was the breakup mode; sure enough, after various trials to reduce the strength of the breakup mode, the singing was much more pleasing. Although the cap was designed to push the breakup mode as high as possible, we thought it was the cap where breakup occurred, but later discovered it was actually the cone section.
The driver location was selected such that it provides the smoothest response so as to disperse the diffraction energy over a wider spectrum, thus making it less noticeable than a concentrated diffraction.
Single driver design was selected for the folling reasons:
1. Less complications of multi driver interaction, closer to point source for near field.
2. Max SPL is not so critical.
3. Small and simple enclosure for easy placement.
4. Cost is lower.
Enclosure shape was selected based on cost. Generally, I hate these shapes, so to give it a different look, the face plate has a different design.
If there were no cost contraint, probably other designs would be applied.
An externally hosted image should be here but it was not working when we last tested it.
The journey is a long story, but the main improvements were in the drivers.
As you can see, the driver has some slashes on it. Why is it there? The main puspose was to improve the breakup mode just above 20KHz. It also turned out that it improves dissipation of stored energy in other frequencies as well. How was it determined that this breakup mode was causing the problem? I was listeing to Mr. Domingo's singing, and at very specific notes, the image focus would be lost, and the note sounded very harsh. So we looked at the data and it seemed the only possible cause was the breakup mode; sure enough, after various trials to reduce the strength of the breakup mode, the singing was much more pleasing. Although the cap was designed to push the breakup mode as high as possible, we thought it was the cap where breakup occurred, but later discovered it was actually the cone section.
The driver location was selected such that it provides the smoothest response so as to disperse the diffraction energy over a wider spectrum, thus making it less noticeable than a concentrated diffraction.
Single driver design was selected for the folling reasons:
1. Less complications of multi driver interaction, closer to point source for near field.
2. Max SPL is not so critical.
3. Small and simple enclosure for easy placement.
4. Cost is lower.
Enclosure shape was selected based on cost. Generally, I hate these shapes, so to give it a different look, the face plate has a different design.
If there were no cost contraint, probably other designs would be applied.
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Energy is generally stored in the driver mechanically and electrically. Currently I know only a little bit more on the mechanical part. This is where I see most driver manufacturers are treating incorrectly by using damping material on diaphragms. What happens is that the soft diaphragms, although well damped, also absorbs some energy transferred from the VC, thus much low level detail is lost in the process. This is one reason why well damped soft material diaphragmed drivers sound quite "dry" when in a room that is also quite dead. A more adequate approach is to use stiff diaphragm, but use the surround to damp it out properly. The skill is how to handle this properly. Ted Jordan's drivers are good examples of utilizing cone curvature profile to do this. Inspired by his work, I am also looking into this, and the slashed pattern used now will be like icing on a cake.
From an electrical point of view, in the cases I have tried, grounding the motor seems to also help improve the situation, but I have not done too much work on this because it makes difference only after the diaphragm section is properly done.
What happens after these result in measureable improvement, if the recorded performance is in a hall, then the delayed reflections of the hall are clearly separate from the performer during playback, the performer has a more focussed location, and the performance skill of handling the instrument is more evident. Most people describe this as more transparent. In fact, the same thing is aparent in audio interconnects, as I demonstrated to a small group two days ago.
From an electrical point of view, in the cases I have tried, grounding the motor seems to also help improve the situation, but I have not done too much work on this because it makes difference only after the diaphragm section is properly done.
What happens after these result in measureable improvement, if the recorded performance is in a hall, then the delayed reflections of the hall are clearly separate from the performer during playback, the performer has a more focussed location, and the performance skill of handling the instrument is more evident. Most people describe this as more transparent. In fact, the same thing is aparent in audio interconnects, as I demonstrated to a small group two days ago.
Hi,
In generally I am both an advocate of "overtoe-in" and not only Jordon was onto that. JBL made for example one of my most favourite commercial HiFi Speakers, the Everest, with an assymetrical coverage pattern Constant Directivity horn to attain the same results a different way.
In no way am I suggesting that JG's design in progress has no mertit, it will likely be an excellent choice for a specific application, arguably one I personally have little call for, even if at the very same time I am doing design studies for commercial products that look like not miles of JG's ZDL concept and for similar applications.
I kind of took issue with the "Zero Diffraction" label, as this went again the physics of diffraction as I learned them.
Ciao T
In generally I am both an advocate of "overtoe-in" and not only Jordon was onto that. JBL made for example one of my most favourite commercial HiFi Speakers, the Everest, with an assymetrical coverage pattern Constant Directivity horn to attain the same results a different way.
In no way am I suggesting that JG's design in progress has no mertit, it will likely be an excellent choice for a specific application, arguably one I personally have little call for, even if at the very same time I am doing design studies for commercial products that look like not miles of JG's ZDL concept and for similar applications.
I kind of took issue with the "Zero Diffraction" label, as this went again the physics of diffraction as I learned them.
Ciao T
For whom? The only BIG problem in audio I know of is people obsessing about irrelevant details rather than concentrating on the big picture.
+1 There are many audio enthusiasts that have never owned or heard an audio system that excels at retrieving low-level detail, and all other things being equal it's that low level detail that separates mid-fi from hi-fi. It's also the reason that so many mid-fi owners don't hear differences in cables and caps and what-not... cable and cap differences are for the most part heard in low level detail, and if one's system can't reproduce low-level detail then common sense would tell you that you're not going to hear differences.Both details and big picture count. The devil is in the details.
Also, there are many people that accept what is most convenient. Sometimes I will ask people without too much audiophile experience to listen. In one ocasion, some old friends not into audio expressed that certain improvements can be clearly heard on well recorded music that used very simple instruments, but not audible with very complicated music. To my ears, the system without any improvements already sounded very good, and I did not expect them to hear any difference. So it's also a matter of continuous learning process, and a general feeling what the ideal system would sound like. I personally have learned from a variety of people on what to listen for, and when I ask people to audition things, I asked them to just tell me what they think is good or bad, the more they can describe what they hear, the more helpfull the information is. I once visited a gengleman that will always ask people that hear his system for the first time to voice 5 things that his system is defficient in; that itself was a challenge for me.
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First. let me wish everyone a Merry Christmas.
Stored energy (or linear distortion) is one of the biggest red herring in audio. I have pointed this out many times over the years. Any natural band pass device will have a certain amount of stored energy associated with it. So how much stored energy is in the system is totally a function of the acoustic bandpass for each drivers, the type (order and family) and frequency of the crossover(s), and how well the crossover is designed to meet the acoustic target. If the target is well matched, the stored energy will approach that of the target response:
Stored_energy_1
The crossover between individual pass bands, woofer to tweeter for example, can only be removed by going to a linear phase system as shown by the response of the 1st order crossover and the linear phase LR4:
Stored_energy_2
As for the Bodzio UE, from you comments on the SE users group most of the problems you seem to be having with it are a result of the associated equipment and not the UE. Invest $150 in a Delta 101LT sound card and I think your problems will go away. Using VAC which is third party software and the problems you have encountered with it are problems with VAC, not the UE.
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Hi John, probably if you show a driver operating from 1KHz up, it would be more convincing.
My understanding is that energy stored mechanically cannot be solved by anything electrically feeding it. As for UE, I have not done any software debugging efforts, and am not able to do so as I have done on flight safety related software, so I don't think we have enough evidence what exactly the issue is. I will be increasing my system memory to see if the problem goes away, but to ask everyone to use a specific hardware is not reasonable. If every media playing software did that, this market would not expand as it has. That said, It is well known that I am a fan of SoundEasy mainly because it does things in a way I have found very usefull for speaker development. I tend to look at UE as a more end user oriented software, the concept is very good, and I will support it as long as it also satisfies my needs.
My understanding is that energy stored mechanically cannot be solved by anything electrically feeding it. As for UE, I have not done any software debugging efforts, and am not able to do so as I have done on flight safety related software, so I don't think we have enough evidence what exactly the issue is. I will be increasing my system memory to see if the problem goes away, but to ask everyone to use a specific hardware is not reasonable. If every media playing software did that, this market would not expand as it has. That said, It is well known that I am a fan of SoundEasy mainly because it does things in a way I have found very usefull for speaker development. I tend to look at UE as a more end user oriented software, the concept is very good, and I will support it as long as it also satisfies my needs.
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There is stored energy in drivers and cabinets and there is stored energy in the crossover if it is not of the linear phase type. Soongsc, a digital crossover can get rid of stored energy so there is a posibility to feed an electrical signal that corrects mechanical energy storage. We did that in the early 90th at Essex university. I will not go this way here. I will try to make the frequency response as flat as posible and then use low order crossovers so i try to solve the problem in the analog domain.
Joachim, I would very much like to read any information on that if it's available. Normally situations like this are handled by preventing excitation of the structural modes, but this then effects the transient characteristics of the end result.
Ah, yes, it is also possible to time certain aditional signals to absorb the mechanical stored energy actively, but this also alters the on going audio signal as well. So I'd really like to read exactly what kind of conditions you have done this under.
Ah, yes, it is also possible to time certain aditional signals to absorb the mechanical stored energy actively, but this also alters the on going audio signal as well. So I'd really like to read exactly what kind of conditions you have done this under.
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