Soundstage--Imaging Problem....Chorus ll's

[SWL]

Room is 18x15x8' ceilings. Had the speakers on the short wall. No magic whatsoever. Reconfigured the room with the speakers on the long wall. Took measurments to achieve an equilateral triangle (equal distance from speaker to speaker to sweet spot). Nothing.....just two speakers jamming away. Checked all connections. Tried putting the speakers in-out of phase, toed-in, toed- out, forward backward, made them wider then narrower then wide again, in corners, out of corners. This is very frustrating. Cannot get them to image even a little bit. Nothing. Nada.

This is for a friend of mine. He is passive bi-amping the Chorus ll's with a Mac 2500 on the woofers and an HH Scott 299 on the horns. A Jolida JD100 tube cd player.

Any suggestions on why these fine speakers are not imaging? We're stumped here. [:S]

Thanks,

-Scott

[Chris A]

Any suggestions on why these fine speakers are not imaging?

Do you have a picture or diagram of the entire front wall?

I would initially guess that your likely source for lack of imaging is due to early reflections, including floor, ceiling, and especially the area between the speakers. Assuming that you haven't tried this already, here is a test that I got from Roy D.:

"Try pulling the speakers well out in front of racks, electronics, or center speaker, then toe them in to your prime listening position."

I know that you said that you did this, but I'm wondering if you did it far enough to suppress the early reflections.

Also note that any reflective objects at or near your listening position - such as leather couches, etc. - will also result in a significant loss of imaging performance. Use comforters, blankets, or other absorptive material to soak up the hf's, then listen.

Chris

[Chris A]

He is passive bi-amping the Chorus ll's with a Mac 2500 on the woofers and an HH Scott 299 on the horns.

Could you draw a diagram or describe how the "passive biamping" is done?

Chris

[vnzbd]

It sounds very strange not to have any imaging going on, especially with everything that you have tried. Would you say that the sound is more like mono from 2 speakers? After all that you have checked maybe start at the source and work towards the speakers?

[pauln]

My experience is that in spite of placing the speakers to do their best, the greatest contributor to imaging is the type of amplification.The imaging has to be in the signal before the speakers can present it.

[SWL]

Do you have a picture or diagram of the entire front wall?

The front wall is empty except for the relatively small equipment rack that is in the center.

"Try pulling the speakers well out in front of racks, electronics, or center speaker, then toe them in to your prime listening position."

We addressed this appropriately. However, early reflections bass traps etc. have not yet been implemented into this room.

Also note that any reflective objects at or near your listening position - such as leather couches, etc. - will also result in a significant loss of imaging performance. Use comforters, blankets, or other absorptive material to soak up the hf's, then listen.

The room is basically empty at this point. We pulled everything out so as to start fresh. The sweet spot is the center seat of a 7' cloth couch. One other thing is there is a large window directly behind the listening position. It's approx. 10' wide x 5' tall. It has drapes covering it that are somewhat transparent. This weekend we will try some thick velvet drapes.

[SWL]

It sounds very strange not to have any imaging going on, especially with everything that you have tried. Would you say that the sound is more like mono from 2 speakers? After all that you have checked maybe start at the source and work towards the speakers?

Tell me about it. All my Klipsch speakers image effortlessly. I wouldn't say they sound mono....in fact they sound great. They just won't image or produce any kind of soundstage. Yes, we started from the source and worked towards the speakers.

[SWL]

My experience is that in spite of placing the speakers to do their best, the greatest contributor to imaging is the type of amplification.The imaging has to be in the signal before the speakers can present it.

We will try the speakers with one amp next. (not bi-amped)

[DavidF]

Having the mid or high horn drivers connected out of phase of each other between the systems could result in mucky imaging. Any reason to think that the connections from the input terminals to the driver terminals may have been altered?

[pzannucci]

Feeding the speakers a mono signal will show if there is some phase problems between each of the speakers and the drivers. You should have a fairly central image with mono. If it is diffuse, then things are a little out of whack, likely driver phase or some other reflections in the room.

[cfelliot]

Feeding the speakers a mono signal will show if there is some phase problems between each of the speakers and the drivers. You should have a fairly central image with mono. If it is diffuse, then things are a little out of whack, likely driver phase or some other reflections in the room.

If you have a Pink Noise source (AM interchannel noise works well too) that you can drive mono it will be very apparent.

[Southern]

This weekend we will try some thick velvet drapes.

Maybe try a fresh coat of paint with a bold color to complement the velvet drapes.[^o)]

Having the mid or high horn drivers connected out of phase of each other
between the systems could result in mucky imaging. Any reason to think
that the connections from the input terminals to the driver terminals
may have been altered?

Thats what I think the problem is since the Chorus II crossovers have the tweeter wired out of phase.

[Rudy81]

Sounds to me like your mid range is out of phase. If you have a signal generator, try sending select tones to the speakers that are exclusive to the frequency of each set of drivers. You should get a reasonable image from each set....let us know how it turns out.

[Mike Dubay]

Another thing to check is the biamping is correctly done with each left channel on the left drivers and each right channel on the right drivers. I cross wired my mid's once, left switched with right, which caused very poor imaging.

[SWL]

Yesterday we took another crack at it.

First thing we did was hang some thick moving blankets behind the listening position covering the window. After doing this we finally got some action going on between the speakers. A minor amount of imaging but we finally had something.

Then we went inside the cabinets and checked the wiring with the schematics. Everything was correct.

Next, we smacked each other because we discovered the balance was off. Flip-flopped the wires and gained a little more imaging.

Added some ATS acoustic panels (24"x24"x2") at the reflection point behind the horns. At this point we're getting significant imaging and soundstage. It's not real "vivid" but we're getting somewhere. Thursday, I'm gonna drag some of my acoustic treatment over there so we can apply it to the early reflection points as well as a couple of bass traps.

Should be interesting...

[Rudy81]

Glad to hear you are making some headway. I use imaging and soundstage as a basic measure of a system's worth. If I don't get good imaging, instrument placement and soundstage, I keep looking elsewhere. Keep us informed. You might try some acoustic panels at the two side reflection points for each speker. That should dramatically cut down on any high frequency problems that are muddying up your image.

Also, how close are the speaker to the back and side walls? If you are too close to the side and rear walls you will be getting better bass performance, but at the cost of improved imaging and soudstage. If you move the speakers away from the side and rear walls, ensure the distances from the side and rear walls are not equal.

I'm sure you already know all this, but just in case....

[davis419b]

Glad to hear you are making some headway. I use imaging and soundstage as a basic measure of a system's worth. If I don't get good imaging, instrument placement and soundstage, I keep looking elsewhere. Keep us informed. You might try some acoustic panels at the two side reflection points for each speker. That should dramatically cut down on any high frequency problems that are muddying up your image.

Also, how close are the speaker to the back and side walls? If you are too close to the side and rear walls you will be getting better bass performance, but at the cost of improved imaging and soudstage. If you move the speakers away from the side and rear walls, ensure the distances from the side and rear walls are not equal.

I'm sure you already know all this, but just in case....

Hey Rudy, keep going as this is great info ! How do you determine the two side reflection points ?

[Rudy81]

Hey Rudy, keep going as this is great info ! How do you determine the two side reflection points ?

Don, I hope you are doing well.

In the case of speakers you can move away from the corner, you use a mirror flush against the wall and a friend to locate the direct reflection points. Have one person sit at the sweet spot and the other will slide the mirror along each wall. As the mirror is moved away from the speaker, along the wall, the first reflection will be of the speaker closest to the mirror, mark that spot where the person in the sweet spot can see the closest speaker....focusing on the tweeter and mid range. Now, keep sliding the mirror away from the speaker until the viewer can see the 'opposite' speaker in the mirror. That is the second spot along that particular wall. Then, do the same for the opposite wall.

If you have Khorns in the corners then the second reflection is really the only one in play.

BTW, you can also do this on the floor to determine where to place a rug if you have a hard surfaced floor. If you get really crazy, you can do this on the ceiling and use acoustic planels to treat the ceiling.

[SWL]

I use imaging and soundstage as a basic measure of a system's worth. If I don't get good imaging, instrument placement and soundstage, I keep looking elsewhere.

Agreed. This is our mindset and goal here.

You might try some acoustic panels at the two side reflection points for each speker. That should dramatically cut down on any high frequency problems that are muddying up your image.

That is exactly what we're gonna do, thanks Rudy. This is how my room is treated and the imaging/soundstage is admirable. A first for me personally...and I love it. []

[Rudy81]

Some other things to keep in mind about your 'room' are things such as large reflective surfaces. For example, large fish tanks, large window panes, entire walls filled with CD cases etc, will make good sound much more difficult to obtain.

Overall, HF problems are much easier to tame than LF problems. All rooms have LF issues and those are the toughest to work on due to the size of the traps required and the difficulty in taming LF room modes.

Another issue to consider is the type of seating in the room. If your seat has a high back, like a recliner, it can cause problems just as the sound is arriving in your ears. Some folks use throws or some absorbent material to prevent reflections in that area next to your head.

Room design plays a critical role as well, and we generally have little say in how that is setup, unless you had the room built for audio. A room with an open space into another room on one side is going to cause you problems. A room with a wall of windows on one side and an opening into another large room on the oposite side would be really tough to treat. There are so many things that affect how we hear the speakers. This is why I often say that your room will affect more of what you are hearing than what speakers you have. Until the room is good for sound, any speaker upgrades or changes are usually less than they could be.

Also, with two people working, you can really fine tune speaker position and toe-in for optimum sound. It is a tedious task. There are lots of books on the subject and quite a few web sources. Ethan Winer has a great site that explains many of these concepts. If you are interested, check out www.realtraps.com.