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Edgar last won the day on November 12 2013

Edgar had the most liked content!

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  1. I'm currently running a prototype version of FOURFRONT in my 4.2 system. There isn't much information about it at the Website, but FOURFRONT is a stereo upmix technique. The basic algorithm is capable of upmixing to 9 fully discrete channels (plus another 4 channels for encoded Dolby Surround material), but once beyond 5 channels there's just not enough audio content to go around. a) My listening room is far from ideal. Its weird shape forces me to place the front speakers at about ±20° and the surrounds at ±90°. This works extremely well for motion picture soundtracks, but really doesn't work for music. I find that for music the surrounds need to be either less than ±90° or more than ±90°, but not exactly ±90°. b) As I mentioned, my system is 4.2. Actually it's 5.2, but I split the center channel between the two front speakers. You would not believe the rat's nest of interconnects at the back of my stereo cabinet. c) I have found that it is imperative that all of the loudspeakers "voice" similarly. If not, then it becomes very apparent "which" speaker is making "which" sound. d) I run the stereo feed into a Steinberg UR824 multichannel ADC/DAC, which ships the audio over USB to a Windows computer that does all of the upmix, crossover, and EQ processing and then sends it back to the '824. e) I'm still putting the system together, so no measurements, yet. It's really frustrating trying to get everything right. f) Biggest expenditure so far was replacing my original 7-channel amp (front speakers are biamped, surrounds are full-range, so six channels) with something that sounds better. That's turning out to be a much bigger problem for multichannel than it was for stereo -- if your electronics don't sound good, then the problem gets multiplied by 4 or 5 or 7 or 9 instead of just by 2. - Greg
  2. Edgar

    What would you do with these 12"ers?

    As far as the driver is concerned, no difference. The Qtc of the system is the same as the Qts of the driver. As far as the room is concerned, big difference. With an open baffle the rear wave can cancel the front wave at some frequencies and polar angles. With an infinite baffle the rear wave is separated from the front wave and no cancellation can occur.
  3. Edgar

    What would you do with these 12"ers?

    With that high Qts I'd consider an open baffle.
  4. Edgar

    Anyone heard of this "DIY" Sub Company? GSG Audio

    We should try to collaborate! I have dozens of cabinet designs in CAD, but I don't know CNC G-code. I'm learning from Peter Smid's book, but it's slow going because it's really not well-written. I'm in St. Charles, MO.
  5. Edgar

    Ebay 10% Off Everything

    Whenever I find something on Amazon that is actually sold by an identifiable company (Monoprice, for example), I go to that company's Website and check the price there. More often than not, (price + shipping) on the company site is cheaper than (price + free shipping) on Amazon.
  6. Edgar

    Anyone heard of this "DIY" Sub Company? GSG Audio

    Dayton UM18-22 https://shop.gsgad.com/collections/subwoofer-drivers/products/dayton-um18-22-subwoofer-driver
  7. Edgar

    RCA XLR or Digital out?

    To be pedantic ... XLR digital is almost always AES/EBU, which is intended for professional applications. Coaxial digital is almost always S/PDIF, which is intended for consumer applications. Optical digital (TOSLINK) is almost always S/PDIF. AES/EBU and S/PDIF bitstreams are similar but not identical. But the commercially available integrated circuits that receive the signals are almost always able to decode both. AES/EBU and S/PDIF electrical signals are not quite compatible. AES/EBU is a differential signal while S/PDIF is single-ended. They expect different load impedances. And they use different voltage levels. It is possible to create an adapter so that an AES/EBU device can receive coaxial S/PDIF signals: https://www.electrovoice.com/downloadfile.php?id=971604 I don't know of an adapter that goes the other direction, but it should be possible. Long ago TOSLINK had bandwidth problems, so coaxial S/PDIF was clearly superior to optical S/PDIF. That problem has probably been solved by now, with superior electronics and local buffering and clock conditioning. - Greg
  8. I draw an analogy with automobiles. Modern automobiles, with driver-assistance capabilities -- anti-lock brakes, brake force distribution, traction control, stability control, roll mitigation, blind spot monitoring, forward collision warning and braking, tire pressure monitoring, etc. -- as well as improved design and execution of that design, just keep getting better by every objective criterion. They are quicker, faster, more efficient, safer, longer-lasting, and just plain better than anything previous. Still, there is a visceral delight in driving an old-time auto that had none of those things. It's not better; it's different. In the same way, audio just keeps getting better. But there will always be a special charm associated with dragging a rock across a piece of vinyl plastic, amplifying those signals with a single-ended tube amp, and playing it all through a fully passive system. It won't be better; it will be different. I run a state-of-the-art digital system in my home. The sound quality can be amazing at times. But my father left me a single Jensen H-222 coaxial driver that produces delightful sounds. It's probably not high-fidelity by any objective measurement, but I find that I can enjoy it as much as the digital system under the right circumstances. And regardless of where audio technology takes us, there will always be a few of us who still appreciate that.
  9. EQ is like medication -- just the right amount can make you feel better, but too much can kill you. A modest amount of broad boost or cut that flattens a loudspeaker's response is usually OK. Trying to make an 8" woofer extend down to 20 Hz is not. Some of the old-time manufacturers made "cut-only" EQ, because they found that people didn't understand what they were doing and tried to boost their way out of comb filtering and natural notches caused by cancellation. You can accomplish more with a few hundred dollars in acoustical treatment than you can with a supercomputer trying to EQ a bad room. My opinion as a signal processing engineer: Digital EQ can do amazing things, but at some point it becomes "fun with numbers" because nobody in their right mind would want to exploit those extreme capabilities. "Observe due measure; moderation is best in all things." - Hesiod (c.700 bc)
  10. Edgar

    La Scala Mods

    Folks, we're dealing with wavelengths between 2 and 22 feet. A fraction of an inch here or there isn't going to make the slightest bit of difference in the response. Find a set of plans that is self-consistent (i.e., all of the angles and edges line up with each other and meet where they're supposed to meet) and build it. It'll be fine.
  11. Edgar

    La Scala Mods

    https://community.klipsch.com/index.php?/topic/156597-university-classicdean-horn-profile-need-driver-choice-help/&do=findComment&comment=1864766 https://community.klipsch.com/index.php?/topic/156597-university-classicdean-horn-profile-need-driver-choice-help/&do=findComment&comment=1865145
  12. Edgar

    La Scala Mods

    Referring to pieces 2, 3, and 4 in the original University drawing; wouldn't it be easier to make them all perpendicular to the base piece 5, and then add a solid wedge reflector at the correct angle? That's how Klipsch does it, except that Klipsch splits the path two ways instead of just one.
  13. Edgar

    Greg Roberts of Volti likes Border Patrol amps

    You know, I am reminded of the old "Mercedes ... Granada" lookalike ad campaign. I suspect that many here are too young to remember it. https://www.hemmings.com/blog/2018/05/23/the-ford-granada-like-a-mercedes-benz-450se-with-a-16319-rebate/comment-page-1/
  14. Edgar

    Greg Roberts of Volti likes Border Patrol amps

    I have to concede that point. Greg's not always the easiest person to get along with. But the Volti products appear to be first-rate ... no matter who actually designed them.
  15. Edgar

    Greg Roberts of Volti likes Border Patrol amps

    I speak only for myself.