Jump to content

Xilica up and running!


Ziggurat

Recommended Posts

11 hours ago, Dave A said:

Somewhere on the forum there is an article on a study done on how to get the widest perception of stereo. I think the example they used was pretend you had a couch in your listening area. The right channel would point to the left end of the couch and vice versa. I have had good success with smaller speakers doing this. The 402 and super MWM behave a bit differently though. I never point speakers right at me anymore though under any circumstance.

Tom Danley told me to do the same thing. Crossfire, I call it.

Link to comment
Share on other sites

This is going to be I interesting when I get mine hooked up... I do not have gain controls on my B&O AMP modules. I forgot that when I ran my old Xilica I had a stack of Yamaha Pro amps.

Sent from my SM-T550 using Tapatalk

Link to comment
Share on other sites

On 10/8/2019 at 6:21 AM, Dave A said:

How you aim those 402's is important too. I find if I tilt them forward and then focus left to right to be at an imaginary point behind me they work better. You are going to be surprised at the difference just aiming them will make.

 

When I built the bases for the 402s, I thought it would make no sense to have them aimed over my head, so I tilted them forward experimentally.  7 degrees seemed to line them up so that they were directly on-axis in the vertical plane, so I bent the brackets carefully (2 per horn) to give the tweeters that 7 degree forward tilt.  Since the ceiling is only 8 feet high, and the top edges of the horns are at about 5 foot 7, I thought ceiling bounce might be an issue, but the forward tilt makes it inaudible, so that's one issue put to bed.

 

As for the toe-in in the horizontal plane, I'm going to go a bit wider and see how I like it.  That "width of a sofa" suggestion sounds logical.  So far, the sweet spot has gone from the width of my head to about 2 feet wide.  I'm curious to see what the next increment produces.

  • Like 1
Link to comment
Share on other sites

4 minutes ago, Islander said:

 

When I built the bases for the 402s, I thought it would make no sense to have them aimed over my head, so I tilted them forward experimentally.  7 degrees seemed to line them up so that they were directly on-axis in the vertical plane, so I bent the brackets carefully (2 per horn) to give the tweeters that 7 degree forward tilt.  Since the ceiling is only 8 feet high, and the top edges of the horns are at about 5 foot 7, I thought ceiling bounce might be an issue, but the forward tilt makes it inaudible, so that's one issue put to bed.

 

As for the toe-in in the horizontal plane, I'm going to go a bit wider and see how I like it.  That "width of a sofa" suggestion sounds logical.  So far, the sweet spot has gone from the width of my head to about 2 feet wide.  I'm curious to see what the next increment produces.

The width of a sofa is for smaller speakers and not the 402. When I tried that with the 402's it did not work so well. The couch idea toe in would place the "focal" point in front of you not behind you.

  • Like 1
Link to comment
Share on other sites

35 minutes ago, Dave A said:

The width of a sofa is for smaller speakers and not the 402. When I tried that with the 402's it did not work so well. The couch idea toe in would place the "focal" point in front of you not behind you.

 

Dave, I'm not clear on what you mean.  If the speakers are barely toed in, as they would be in the "sofa width" arrangement (l'm measuring using the inboard faces od the speakers, not the centres), how would the 'focal point' be in front of me?

Link to comment
Share on other sites

The article I quoted would have the rt hand speaker pointing to the left end of the couch and vise versa. Now if you draw an imaginary line from the right speaker to the left end of the couch and the left hand speaker to the right end the "x" will be crossed in front of you. I am referring to where the imaginary x cross point as the focal point as that is where the speakers are aimed.

Link to comment
Share on other sites

7 hours ago, Dave A said:

The article I quoted would have the rt hand speaker pointing to the left end of the couch and vise versa. Now if you draw an imaginary line from the right speaker to the left end of the couch and the left hand speaker to the right end the "x" will be crossed in front of you. I am referring to where the imaginary x cross point as the focal point as that is where the speakers are aimed.

 

Ah, now I understand.  Sorry about the confusion.  For some odd reason, I was turning around in my mind and facing the sofa, so left became right.  I read it as "from the right speaker to the right end of the sofa", and so on.  That would result in much less toe-in, and place the focal point far behind the sofa.  That should make for a pretty wide sweet spot.

Link to comment
Share on other sites

1 hour ago, babadono said:

That's wild. So are Jubes WG speakers?

 

Yes.  But they're really horn-loaded loudspeakers with controlled directivity down to 100 Hz, at which point the room corner becomes part of the first full 1/4 wavelength of the bass frequencies.  That's why it's so important to put corner horns fully into the corners--not pulled out away from the corners.  Midrange early reflections can be easily handled by one row of 2' x 2' absorption panels each on the side walls and front wall, the height of the Jubs.

 

In the case of K-402s and KPT-KHJ-LF bass bins, because they have almost spectacular SPL out to 40-50 degrees off-axis (see the polar plot below for the K-402--with the blue-green color being the horn's -6 dB contour), the towing-in scheme from the article actually doesn't do what it does like with poorer performing horns--which tend to beam a great deal to create the effect mentioned in the article. 

 

K-402-MEH horizonal normalized sonogram.jpg

 

I've found that toeing in the K-402s and KPT-KHJ-LFs (Jubilees) very slightly in front of the listening position is probably the best solution, but note that I've treated my listening room to avoid early reflections from the center of the front wall (where a lot of folks place their electronics and flat screens--which need to be covered with absorption to avoid issues with phantom center channel imaging). 

 

In your case, the Jubs are far enough apart to avoid near-field reflections from the center of the front wall.  All that is needed is a row of 2' x 2' absorption pads on each side of the K-402s the height of the loudspeakers, and something absorptive on the floor out to about 3-4 feet in front and the full width of the loudspeaker (to control floor bounce).  The room acoustics do the rest. 

 

Horns are not "lenses", BTW.  "Waveguides" (a misnomer) are all horns.  Horn lenses were used by JBL in the '50s-'60s (using Bart Locanthi's patent that was granted while he was still working at the Jet Propulsion Lab). JBL later abandoned horn lenses in favor of better designed horns that can do the horizontal polar coverage without all the diffraction issues of the horn lenses. 

 

Chris

 

 

 

 

  • Like 1
Link to comment
Share on other sites

@Chris A the reason I asked about this is @Westcoastdrums came over a couple weeks ago to audition my Jubes. I think he liked everything about them except the imaging. He made me critically listen to what he was hearing. By the time he left we had moved the speakers about 3 feet each from the side walls, so 6 feet closer together. The stereo imaging was MUCH improved.

Link to comment
Share on other sites

1 minute ago, babadono said:

@Chris A the reason I asked about this is @Westcoastdrums came over a couple weeks ago to audition my Jubes. I think he liked everything about them except the imaging. He made me critically listen to what he was hearing. By the time he left we had moved the speakers about 3 feet each from the side walls, so 6 feet closer together. The stereo imaging was MUCH improved.

Honestly Eric, and this is my personal opinion from being in the room and hearing them, I think they need to be moved in slowly 6 inches each at a time until the phantom center snaps in much stronger.   Phantom center is present, but I prefer it much stronger. The quantity and depth of the bass tells me the jubes easily have room to come away a little more from the walls.  That is just my personal preference. I'll let @Chris A convince you to lower the horns 😂.   IMO they need it and I understand why. They sound a lot better standing up.  For initial rough setup, I left with a smile and a full belly.  Thanks again for welcoming me over.  Good times.   Too bad I didn't have the CDs I actually wanted to listen to.   Oh well. 

  • Like 1
Link to comment
Share on other sites

58 minutes ago, babadono said:

By the time he left we had moved the speakers about 3 feet each from the side walls, so 6 feet closer together. The stereo imaging was MUCH improved.

They're not cornerhorns in that placement.  You're losing about an octave to an octave and a half of deep bass (60-100 Hz cutoff when placed out of the corners vs. 31 Hz cutoff in the corners).  That's a huge loss.

 

Perhaps placing absorption on the walls next to the Jub mouth exits (a total of twelve 2' x 2' pads, mentioned above) is a more useful approach--with the Jubs back into the room corners, within 12 inches of touching the adjacent walls.

 

Chris

Link to comment
Share on other sites

If you've got the Jub bass bins touching the front wall, you're only losing ~7-10 dB at 34 Hz (from the KPT-Jubilee/535-B cut sheet), which assumes that they are being placed in quarter space against the front wall.  If you pull them out 3 feet from that wall, you're losing everything below ~100 Hz--just like a Khorn.

 

If that absorption trick didn't work as advertised, I wouldn't recommend it.  It works very well however, and the imaging covers side wall-to-side wall (with 31 Hz cutoff as shown below):

 

1189506204_RightJubSPLandphaseresponse.thumb.jpg.a934aeb26fb051dbfd0d8f4ec237854c.jpg

 

Chris

Link to comment
Share on other sites

Here are the PEQs that I used for that measurement, in case you're wondering if I used some form of low frequency PEQ boost (which I didn't)...

 

1891726791_JubbassbinPEQs.thumb.JPG.08a215986011fa50a9947a58739e5f3e.JPG

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...