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mwmkravchenko

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mwmkravchenko last won the day on November 22 2017

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About mwmkravchenko

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    Advanced Member

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    www.kravchenko-audio.com

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    Male
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    Perth Ontario Canada
  • Interests
    Music. Good recordings and sharing the experience of both.

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  1. mwmkravchenko

    Inductance modelling

    I completely forgot about this spreadsheet. Thorborg advanced inductance spreadsheet If I remember half of what I have forgotten, I'd be more dangerous
  2. mwmkravchenko

    Inductance modelling

    There are a few more papers other than the Thorborg paper that Bolserst used. If anyone wants the papers let me know and I'll be happy to forward them to you.
  3. mwmkravchenko

    Inductance modelling

    The complex inductance capability is finally incorporated in to Hornresp. Nice to see. Much of the effort belongs to bolserst and David McBean. It's a situation of providing the correct frame work and the proper papers behind that framework. Hornresp is getting pretty interesting these past few months. Moving closer to LEAP kind of computational simulation capabilities.
  4. mwmkravchenko

    New additions for db site (need feedback)

    Kyle I like the new format that you have proposed. Nice. Only one thing I am wondering. Are you limited to a certain window height for the graphs? Or are you trying to keep the same vertical perspective on the distortion plots. The Klipsch sub should have Mr. K turning in his grave!
  5. Agreed. I'm very much not a fan of one curve fits all and auto generated room EQ. All you have to do is move about the room a little bit and your wonderful EQ is out the window.. We are basically agreeing on the room timing measurements. My unstated reasoning is that an accurate measurement cannot be made without a stimulus that actually excites all the room modes. In most cases this precludes the MLS types of signals. You need chirps and or discrete gated sine wave stimulus to really excite what can happen below around 200 hertz. DFT gating is also very important to be chosen correctly as you have pointed out. And the correct type of math Math on the DFT. Choose wisely or suffer the consequences
  6. I'm guessing that this Audyssey EQ is a sliding dynamic loudness contour. That does have application when you are listening at levels below 70 to 75db averaged. Simple comment on room measurements. They are very dependent on the stimulus made to take the measurement and the type of math applied to perform the measurement. The errors multiply rather rapidly depending on the choices made. I know of no professional who works in acoustics that looks at averaged measurements and gives them any worth. Raw measurements are where the real information lies. Lastly. I may have not posted the links to all the Sean Olive Papers and may be remembering What I was reading in the JAES papers freely available and also on the JAES website. But I know for a fact that the reference speakers were in a standardized listening room and that the panel of trained listeners preferred the sound characteristics associated with a standardized semi-reverberant room. Not an anechoic reproduction also called diffuse field EQ that was the norm for a few years back.
  7. The writers of those articles would have a very healthy argument that you are incorrect. And so would I I often use a high quality pair of headphones as a reference when working on loudspeakers. The entire basis of the articles I cited are the relationships between the sound of an accurate pair of speakers and an accurate pair of headphones. Don't allow what you have in a headphone sway your decision. There are some headphones that have been designed with this type of carefully crafted contour. The data for this type of EQ matching loudspeakers is widely available in many reports and there is even standards that are in the works to define an accurate headphone response. They all use a well setup loudspeaker as a reference.
  8. http://seanolive.blogspot.ca/2014/01/the-perception-and-measurement-of.html http://read.uberflip.com/i/324330-lis-2014/22 http://seanolive.blogspot.ca/2008/12/loudspeaker-preferences-of-trained.html A lot larger pool of people than I have ever had the chance to work with agree that listener preferences are universally agreed upon regardless of age. Good sound is simply put, the right sound. Right in the sense that it accurately reproduces the sound of a live acoustic event. Caveat being that when you set up a loudspeaker system in this way many recordings are exposed for a series of poor choices. And poorer outcome in reproduced sound. One last note. There should be no difference between accurate reproduction on a loudspeaker and accurate reproduction on a headphone. That is the anchor of this series of research articles. After all you are using the same set of ears for both types of listening aren't you?
  9. Some how I don't quite agree with that summation. True some people like little or no treble. But that is not really attributable to age. I have clients and colleagues that are long in the tooth but really appreciate an extended top end response. I do agree that your idea of a generally accepted loudspeaker response is best described as subjectively flat. Most systems that I have listened to that were dead flat were very bright on the top end. My personal work aims for a combined listening position that is down a few db beyond 10 khertz. Down about 1.5 to 2 db in the last octave.
  10. Welcome to my world has been ringing in my head after reading your post Brian. You are ironing out many of the problems, and discovering new ones. It is what engineering actually consists of.
  11. Happy to hear you have attained your goals. Now the real fun begins. Listening to music!
  12. Nice work! Ground plane. Get friendly with some pieces of plywood and duct tape. Place them on the pavement and tape the joints. Two sheets will allow you a 2 meter measurement distance all around your box.
  13. mwmkravchenko

    UBER 24" possible Project

    I'm from Missouri. Can you explain this statement? Also in this relatively small enclosure at what power level can you actually get this remarkable excursion you mention above?
  14. Steve you are much faster (better) at math than I am. 30 years rusty is I. It takes me a while but I eventually get there. I'm the guy all the egg heads in the physics classes would ask how the formulas applied to real life. And also the guy who regularly struggled big time with remembering them. Fun watching you run rings around me. It's interesting talking to you via this discussion. You have a slightly different perspective on the same subject and I appreciate it. Plus I enjoy a good discussion. We agree on the fundamentals. I'm fleshing out the differences. The ideal gas model does not take into account non-linearity. That's my point. And it has been demonstrated mathematically and empirically through test and measurement that the closed box heating of the air internally changes the properties of the air spring. If you are well read enough to have a great conversation so far I'm guessing you have at least touched a bit on this. The heat sources are two fold the compression of the air as described in the ideal gas model. This is insignificant really. The main contributor is the driver motor inefficiency. Even a 100 db/watt driver is over 93% inefficient. As in for 100 watts input 93 watts are turned into heat. Like a toaster! http://www.sengpielaudio.com/calculator-efficiency.htm So with increase in temperature the driver suspension parameters and DCR are now being modified due to changes in materials temperature and stiffness goes down. Generally a desirable thing in a sealed enclosure. But it does change the distortion products. They go up. "A driver designer would argue my point that higher Vas will always be better because the suspension has to be stiff enough to adequately support the moving parts. :)" High Vas is a softer suspension. Never said back EMF is the same as inductance. So I agree there to. Simply said that you canna ignore it captain! "With back EMF, the energy is stored in the mechanical sub-system, where it oscillates between kinetic (motion of the driver) and potential (air + suspension spring) forms. With inductance, the energy is stored in the magnetic field around the coil. They act in very different ways." OK now you are pulling a Mark. Looks like you were tired and thought one thing and typed another. I'm sure you mean this statement a little differently than I'm reading it.
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