Jump to content

Photo of La Scala II with speaker grill removed


Tizman

Recommended Posts

9 hours ago, glens said:

If I were to do something like that I'd surely cover the surface in front of the tweeter side-to-side and all the way forward with some fairly thick and loose-matted felt or equivalent, overhanging the edges ~1/8 inch to subdue reflections and especially diffractions from the edges.  And I'd expect the best "focus" to be found with the tweeter diaphragm slight behind that of the midrange driver due to crossover phase shift.

I have the tweeters of my H3 up on top of the cabinets to the back lined up with the mid horns. I have a layer of high density fiberglass sheet on top of the cabinet in front of the tweeter horn covering the cabinet surface in front of the tweeter. One would expect there to be a great deal of reflection from the hard flat cabinet top, I know I did but in practice I hear very little difference between having the fiberglass sheet in place or not. I leave it there but I am about to the point of removing it as it looks less than attractive and it does very little to help the sound.

Link to comment
Share on other sites

23 minutes ago, Maximus89 said:

That's nice! What tweeter is that and will it work with an AA?

I've seen photos of this time aligned tweeter being mentioned, but i've never seen any placed vertically as @moray james mentioned.  I have however seen custom mid horn options with built in tweeter cutout placed vertically and iirc i've seen the old original KHorns have the tweeter mounted inside the mid horn vertically.

I cannot help you with any info regarding the tweeter on the Khorn I simply found the photo on line (while looking for Bruces LaScala) and posted it so you could have a visual of what we were talking about.

Link to comment
Share on other sites

Actually, the absorption across the top of the cabinet mostly absorbs midrange acoustic energy that re-radiates from the top of the cabinets, but is spilled from the midrange horn, starting at about 2 kHz, down to the woofer/midrange crossover frequency interference band.  (Higher frequencies from the tweeter are typically diffracted and absorbed more effectively by themselves.)  This is the famous midrange "pattern flip" or "collapsing polar" horn characteristic to spill excess acoustic energy below the point of half-wavelength vertical mouth dimension--corresponding to that stated 2kHz start-of-pattern loss in the vertical direction.

 

PWK apparently liked to use wide-and-flat (pattern flipping) midrange horns in order to avoid having to add notch filters to his crossover networks to compensate; otherwise he would have had to use the notch filters with (better performing) controlled directivity horns.  I believe that Klipsch Corp. has generally not used those type of midrange horns since a few years before PWK's passing--except for updates to PWK's own Heritage designs--in deference to his memory.  This is the source of what generally gives the Heritage series of loudspeakers their bad name among novices that haven't learned to put down carpet on the floor and to use the loudspeakers in rooms with higher ceilings than 8 feet--in order to avoid the timbre-shifting acoustic energy from being re-radiated back to the listener in the ~400-2000 Hz band.

 

Chris

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Thanks for all the replies and the excellent information contained within.  I am getting a basement area ready for a listening room/home theatre, and will be using a DIY pair of Klipsch inspired speakers there.  My La Scalas are upstairs in the family room and will remain there, unmolested.  

2 hours ago, Chris A said:

This is the source of what generally gives the Heritage series of loudspeakers their bad name among novices that haven't learned to put down carpet on the floor and to use the loudspeakers in rooms with higher ceilings than 8 feet--in order to avoid the timbre-shifting acoustic energy from being re-radiated back to the listener in the ~400-2000 Hz band.

The ceiling in the new room is around 7.5’.  Would a carpet and sound absorbing panels on the ceiling be the ticket if I use Klipsch Heritage style horns in my DIY speaker?  Alternately, as may end up being the case, if I use CD horns instead, will these room treatments be less needed?  

Link to comment
Share on other sites

3 hours ago, Chris A said:

Actually, the absorption across the top of the cabinet mostly absorbs midrange acoustic energy that re-radiates from the top of the cabinets, but is spilled from the midrange horn, starting at about 2 kHz, down to the woofer/midrange crossover frequency interference band.  (Higher frequencies from the tweeter are typically diffracted and absorbed more effectively by themselves.)  This is the famous midrange "pattern flip" or "collapsing polar" horn characteristic to spill excess acoustic energy below the point of half-wavelength vertical mouth dimension--corresponding to that stated 2kHz start-of-pattern loss in the vertical direction.

 

PWK apparently liked to use wide-and-flat (pattern flipping) midrange horns in order to avoid having to add notch filters to his crossover networks to compensate; otherwise he would have had to use the notch filters with (better performing) controlled directivity horns.  I believe that Klipsch Corp. has generally not used those type of midrange horns since a few years before PWK's passing--except for updates to PWK's own Heritage designs--in deference to his memory.  This is the source of what generally gives the Heritage series of loudspeakers their bad name among novices that haven't learned to put down carpet on the floor and to use the loudspeakers in rooms with higher ceilings than 8 feet--in order to avoid the timbre-shifting acoustic energy from being re-radiated back to the listener in the ~400-2000 Hz band.

 

Chris

  This is my take on reducethe contribution from the top and bottom panels o my LS ii. May not work as well as the fiberglass. 

  The radiating area of the panels is 4 square feet. Each.

45A360F0-5FBC-4E96-9C91-4484997F84E5.jpeg

94B2EFAE-FDF8-4B57-BD96-24F92D154265.jpeg

Link to comment
Share on other sites

That is a photo of the inside of the top hats. Lined with 1/2” closed cell rubber. Added over two pounds to each top hat. The mass does a little mass dampening, more is the rubber will not transmit much energy to the wooden panels.

  The dampening material looks better on the inside.

Link to comment
Share on other sites

14 hours ago, Chris A said:

Actually, the absorption across the top of the cabinet mostly absorbs midrange acoustic energy that re-radiates from the top of the cabinets, but is spilled from the midrange horn, starting at about 2 kHz, down to the woofer/midrange crossover frequency interference band.

I thought Chris A was talking about the midrange horn’s radiating pattern coming out of it and then rolling around and off the top, and not the vibrations of the top panel. I would think that the top panel vibrations would be fairly low in level.

  • Thanks 1
Link to comment
Share on other sites

my top rattles quite a bit. I've got decorators not unlike modern Khorns where the top just sits on the LF, but i need isolation pads or feet. Do they need to be specifically "isolation" pads/feet, or any furniture pad/rubber feet will do?

Link to comment
Share on other sites

  The ones used on the LS ii look to be standard rubber. They should offer some isolation.

  Chris will have to comment on the noise he has measured and source of it. I read it as the top panel being activated by the K400. The three wooden cross braces installed by Klipsch are there for a reason. 

  The knuckle test yielded a lower output and frequency. But that was knuckle on the outside of the top panel. Knuckle test on the inside yields no noise. 

  I lined one checked the resonance and then the other. After checking them it seemed to be a good thing to add the rubber. 

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...