Planar Speaker Asylum

Welcome! Need support, you got it. Or share your ideas and experiences.

Return to Planar Speaker Asylum

Planar Speaker Asylum

RE: Advice from Magnepan

99.245.112.210

Jonathan 90

In Reply to: RE: Advice from Magnepan posted by josh358 on February 13, 2012 at 15:40:38

Normally I avoid the topic � I settled years ago with tweets outside � I was cleaning and rearranging the equipment other day � when this thread came to mind and propelled me to revisit the subject - on first listen with inside tweets � the impression was one of the soundstage being slightly out of phase � it wasn�t of course.

Magnepan states: �To obtain correct phasing between the tweeter and bass of the MG1.6, the tweeters should be placed on the outside� � I readily heard this - continues listening convinces me that the sweet spot is a tad wider � although the images within the soundstage are softer and not as defined � another observation � when engaging the integrated tube amp the sweet spot opens up a wee bit more � razor sharp images within the soundstage is an absolute requirement in my music.

Follow Ups:

RE: Advice from Magnepan - pictureguy 17:23:32 02/13/12 (5)
I'm going to revisit this, too.
Right now, I listen to pole piece side w/ tweets IN.

Does the side you listen to effect (affect?) the lobing? Or the direction thereof?

The way I'm supposed to listen resulted in so much frustration, I had to try something else.
Too much is never enough
- RE: Advice from Magnepan - Jonathan 90 19:04:05 02/13/12 (4)
  "Does the side you listen to effect (affect?) the lobing? Or the direction thereof?"
  
  This is something I don�t lose sleep over � can�t recall this abnormality ever presenting itself as an issue in my space.
  - RE: Advice from Magnepan - pictureguy 23:09:33 02/13/12 (3)
    The reason I asked....and in exactly that manner is simple curiousity. When I flipped my panels around, just a simple rotation in place, the sound was instantly improved. The sweet spot opened up and i ultimately adjusted the toe to about 11 degrees.
    I realized than that the tweeter either led or lagged the bass part of the panel by 90 degrees because of the 1st / 2nd order crossover used.
    My theory was that flipped, the sound now back in-phase, since if the bass leads the mid/tweet, the distance it now is further makes the time delay about equal to the listener.
    A complicated way to say it simply sounded more 'right'.
    
    I was just curious about the lobing since that in a sense confirms my thought. As a total off-topic note, that is the way phased array radar works. They can steer the beam from a flat emitter by phasing the emission across the panel. You should be able to do the same thing with audio?
    
    I'm glad your setup is set and stable. I owned MG-1s for over 2 decades and a rebuild at WhiteBearLake and never had the kinds of problems with setup the 1.6s gave me....until I flipped 'em.
    I'll admit to being over analytical / curious but I always gotta know WHY something works when the change was so.....dramatic.
    Too much is never enough
    - RE: Advice from Magnepan - josh358 06:57:47 02/14/12 (2)
      Sure, you can make a phased array with audio, and it's sometimes done, particularly in sound reinforcement applications. A famous example, though it uses analog components and isn't steerable, is the Quad ESL-63, which uses a phased annual ring array to create a spherical wavefront from a planar diaphragm.
      
      One practical difficulty in using a phased array in audio is that the frequency range is so wide that wavelengths range from about half an inch to about fifty feet. To achieve good directionality, a phased array has to be wider than the wavelength that's being steered. So it's easier to steer the highs than the lows.
      
      Another practical difficulty is expense -- to avoid spatial aliasing, you need drivers that are small compared to the shortest wavelength, and even if you use a binary weighting scheme for the size of the drivers you end up with a lot of drivers and channels of amplification, lots of processing power, many DAC's, etc.
      
      There's also the difficulty of getting a given driver to cover a wide enough frequency range.
      
      Both of these factors have made the approach more popular in sound reinforcement than at home.
      
      Even more interesting than phased arrays or arrays with fixed weightings is wave field synthesis, which has the potential to completely recreate a three-dimensional soundfield. Wave field synthesis is already being employed in some soundbars and commercial/experimental installations, but the power of current systems are limited by cost, e.g., the arrays are one rather than two dimensional and of limited size and resolution. A two-dimensional WFS array that covered the front wall might require 1000 or so channels and drivers. It seems to me that planar technology would be ideally suited to such an approach, since the drivers could be printed on a few large membranes. But you'd still need 1000 channels of conversion and low power amplification as well as the processing power to drive them, so it's something that's going to have to be done in LSI by the large consumer electronics companies if it's to become economical for the home. I think we'll move their incrementally, with one-dimensional arrays first, maybe a few to give a coarse approximation of height.
      - RE: Advice from Magnepan - pictureguy 10:46:52 02/14/12 (1)
        
        In Reply to: RE: Advice from Magnepan posted by josh358 on February 14, 2012 at 06:57:47
        
        I don't know from the amp crossover side, but as for a driver? IF Graphene works out and you can basically mass batch process sheets of selectively conductive material, that may work.
        
        Of course, wouldn't recordings than be the limit? Some studio stuff sounds flat as it is.
        
        Too much is never enough
        
        RE: Advice from Magnepan - josh358 14:51:49 02/14/12 (0)
        
        In Reply to: RE: Advice from Magnepan posted by pictureguy on February 14, 2012 at 10:46:52
        
        Interestingly enough, the same multitrack technology that's destroyed the quality of stereo recordings is exactly what you need for wave field synthesis. All you do is make a dry recording of each instrument or groups of instruments -- multiple recordings if the instrument is directional, like the violin. And you record their position, dynamically if you have to (as in a singer moving around the stage). Then you package the instruments, position data, and the 3-dimensional impulse response of the hall in a file. The reproducing computer can then recreate the hall ambiance and calculate the coefficients for the array, not just to reproduce the 3D field but to manipulate room acoustics, e.g., by suppressing or creating side wall reflections. It would require a lot of DSP to do in real time, but I don't think doing it economically is off the map, anymore than a thousand-channel DAC.
        
        Check out the polystyrene WFS speakers at the bottom of this page:
        
        http://recherche.ircam.fr/equipes/salles/WFS_WEBSITE/Index_wfs_site.htm
        
        Seems to me more sensible to dispense with the separate voice coil!

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors: