Khorn imaging, soundstage and room sweet spot

[Rudy81]

I am almost finished with the room acoustic tretments and was playing around with the "toe-in" of my Khorns when I found that changes in toe-in make a huge differance in imaging and sound stage. I have false corners, which allow me to move my Khorns around rather easily without loosing bass. I have the Khorns on the short wall due to the room being a home theater as well as a listening room. (Room is 20'x27'x9')

I have had the horns toed to "aim" at my sweet spot chair position. I rotated them to the corners of the room (where they would have been without the falsies) and found the soundstage much narrower and more muddled than before, although imaging was great. I was surprised by the magnitude of the change. I then "opened" them up so they would point outside my sweet spot and found that the soundstage opened up considerably, but started loosing the detailed imaging. I realize this is what one would expect by doing this with "normal" box enclosure speakers. But, Khorns are not designed to be this mobile.

I am beginning to understand why most suggest placing the Khorns along the long wall. This set up, in effect, forces the sweet spot seating position to move forward and into the point where the tweeters and mid horns are "pointing" at you. I guess I had missed this point in all the suggestions I have read on the forum in the past. Does this make sense, or have I missed something?

I have read many articles from the Dope from Hope and don't recall anything from PWK that addressed intionally toeing-out your Khorns, probably since the assumption is that they are tied to the room corners. Now I am wondering if those that have the Khorns anchored in the room corners are missing something.

My previous mains were Belles and I had them toed-in as well. I am doing my final tweaking to get the room as acoustically "perfect" as humanly possible. I am also wondering if any of you have quadratic diffusers in the back wall, and what your impressions are of that arrangement?

This should open up a can of worms :-)

[D-MAN]

No worms from me, I'm right with you.

There are some here with seemingly perfect spaces for Khorns. I'm not one of them!

But there are those in less-than-optimum spaces who refuse to unbolt their top cabinets and turn them because they don't like the way it looks being unsymetical or unbalanced.

Personally, I don't like the way it sounds if they don't. But that's just me, and I'm a stinker!

My first thought (which I resisted) was to post "WHAT imaging and WHAT soundstage? We're talking Khorns here, aren't we?"

you know - the main old complaint with horn speakers is that they don't image or throw a convincing soundstage. But they certainly can, if things are attended to properly. Turning or changing the dispersion angle of the mid and high frequency units when in a less-than-optimum space will certainly get you closer to where you want to go.

DM

[Rudy81]

Excellent point, the same effect could be achieved by rotating just the top hat.

[colterphoto1]

If you look at the 45 degree geometry that the Khorn properly fitted into a corner requires, there are some definite optimum charactersitics for a room. The following is my personal thoughts regarding an optimum Khorn listening room.

Long wall helps immensely as using the short wall means the listener must sit very close to the speaker wall, unnatrually close from a furniture placement standpoint.

If the room is say 24 feet wide, the sweet spot is approximately midway between the two Khorns and 12 feet back from the front wall. We know that 12x24 is a bad set of dimensions from a mode point of view. Finding a room that is 24 x narrower than 12 is improbable, so deepening the ideal room to say 15 feet but sitting at 12 from the front wall gives a reasonable seating arrangement while taming some room modes.

I am very lucky in that that my listening room is 21 x 15 feet- sitting 10 feet from the front wall puts me exactly midway between the speakers in the exact center of the horn's radiating pattern. Slightly in front of behind this point (a foot or so) seems to make little difference. Dr Who has run the room mode calculator and found this to be nearly idea.

I do need to build new grille boards to avoid two hot water baseboard radiators, but with the grilles removed from one speaker, both sit with padded tailboards tight against the 1" plaster walls.

Michael

[Dax617]

My room dimensions are similiar to yours except the khorns are against solid corners. I am still struggling with most areas of listening: crossovers, amp pre amp, room treatment etc. The one thing that sets the system apart , in my opinion ,is the depth and soundstage that come along with big rooms. I have a very "live" room right now, just 18' of wet bar, dry wall and cement floor. The hard surfaces have their own down fall but they also seem to impart a live quality to better recordings. I haven't looked to improve they sound stage by changing their position.

T.C.

[Guest " "]

It would be great if someone who has 511b mid horns and a bi-radial tweeter such as the st-350 could chime in and give a mini review of their sound stage.

[Rudy81]

My room dimensions are similiar to yours except the khorns are against solid corners. I am still struggling with most areas of listening: crossovers, amp pre amp, room treatment etc. The one thing that sets the system apart , in my opinion ,is the depth and soundstage that come along with big rooms. I have a very "live" room right now, just 18' of wet bar, dry wall and cement floor. The hard surfaces have their own down fall but they also seem to impart a live quality to better recordings. I haven't looked to improve they sound stage by changing their position.

T.C.

My room was also a bit live for my taste. I just finished making 8 2'x8'x2" absorbers that I placed along the side walls between the speakers and my sitting postion. It made a marked differance and the current sound is very natural. Actually, I found the sound to be more crisp and the soundstage to be more precise than before. I did some real time tests before permanently mounting the absorbers and there is a very noticeable differance. Soon, I will be adding curtains around the screen in front and that will pretty much finish the major changes.

I sure do love the larger room. Prior to this move the gear was in a much smaller room and as they say, bigger is better.

[Kudret]

Hi,

My room is 17x34 and I have my Khorns along the short wall. I had them tucked into the corners for a few months. The biggest isue with this setup for me was the feeling of sitting on the stage as I would hear some instruments from far right and others from far left. I also unbolted the top sections and experimented with different toe-in configurations, but of course this did not solve the "sitting on the stage" problem.

Then I moved the speakers out of the corners, about 12' away from each other and toed-in towards the sweet spot. I have not built any false corners yet and at the moment I am again experimenting with different toe-in configurations. My biggest problem with this setup is the lack of a realistic sounstage. There is no separation between the location of instruments and vocals. What I prefer to have is just the opposite; laid back sound with a soundsatge extending from one speker to the other.

I have tried two different preamps, two different amps with two different source components, but so far I cannot say that I am happy with my Khorns. I also have a pair of Cornwalls and I am planning to upgrade their crossovers to see if they will give me the sound I am looking for. Mind you, Cornwalls would be more difficult to drive with 3.5WPC-7WPC SET and PP amps I am using.

Kudret

[PrestonTom]

Hi,

My room is 17x34 and I have my Khorns along the short wall. I had them tucked into the corners for a few months. The biggest isue with this setup for me was the feeling of sitting on the stage as I would hear some instruments from far right and others from far left. I also unbolted the top sections and experimented with different toe-in configurations, but of course this did not solve the "sitting on the stage" problem.

Then I moved the speakers out of the corners, about 12' away from each other and toed-in towards the sweet spot. I have not built any false corners yet and at the moment I am again experimenting with different toe-in configurations. My biggest problem with this setup is the lack of a realistic sounstage. There is no separation between the location of instruments and vocals. What I prefer to have is just the opposite; laid back sound with a soundsatge extending from one speker to the other.

I have tried two different preamps, two different amps with two different source components, but so far I cannot say that I am happy with my Khorns. I also have a pair of Cornwalls and I am planning to upgrade their crossovers to see if they will give me the sound I am looking for. Mind you, Cornwalls would be more difficult to drive with 3.5WPC-7WPC SET and PP amps I am using.

Kudret

Kudret,

The problem you are having is due to the geometry. Please do not spend money & effort trying different amps etc.

The K-Horns can give a convincing image and there will be a believable separation of the instruments etc. You have placed them very far apart and the extent of laterality is going from cabinet to cabinet. This is the way it should be; however, for you the angle is too large. One solution, and not a perfect one, is to add a summed center channel. This will do a number of things. Relevant to your situation is that is will "dilute" the far left and the far right signals and place them more toward the center (center channels are used by a number of folks). This is also done electronically in some of the old pre-amps (Dynacos did this - it was selectable)

When you adjust the toe-in on the speakers, several things are happening. One is you are changing the frequency response that the listener receives and you are also affecting the ratio of direct energy to reflected energy (bouncing off the walls) received by the listener. This will effect the ambience, dispersion and precision of the spatial image.

Taking the cabinets out of the corners is not a great idea, you have greatly altered the response at the lower frequencies. Please put them back in the corners. If the spatial positions of the various instruments are not coming from distinct locations, you may have dirvers wired out of phase or the room itself may have too much reverberation.

This is a solvable problem.The issues are room acoustics and geometry when placing the cabinets. If someone suggests a different amp or crossover .... save your money.

Good luck,

-Tom

[Kudret]

Hi Tom,

Thank you for your detailed response.

I thought about the center speaker idea, however I have to admit I wasn't too keen on using a center speaker, and the same goes for building false corners. [:$]

Taking the cabinets out of the corners is not a great idea, ...

Does this apply to the whole cabiner or the bass bin for the most part. How about moving the bass bins in the 17' corners, but keeping the top sections separate 12' apart (on stands) toed in. Would this create any major time alignment or other issues.

If the spatial positions of the various instruments are not coming from

distinct locations, you may have dirvers wired out of phase or the room

itself may have too much reverberation.

I will check the driver connections, but I suspect it might be the room. I was planning to get TrueRTA and a Behringer mic to see how my room response is. Should I do this sooner than later?

Kudret

[Travis In Austin]

Rudy,

Great website, and great looking room.

Travis

[colterphoto1]

"Does this apply to the whole cabiner or the bass bin for the most

part. How about moving the bass bins in the 17' corners, but keeping

the top sections separate 12' apart (on stands) toed in. Would this

create any major time alignment or other issues."

absolutely positively leave them together. Time alignment is an issue. They MUST be tucked into the corners or the low end below about 70 hz just disappears. I had one of mine out about 3 inches on either side and it had horrendous bass response in comparison to one tucked tightly in.

This whole thing about toeing in Khorns is somewhat ludicrous. And the false corners are not terribly effective unless they are much larger and stiffer than what we normally see posted in photos. That is a 90 degree K400 horn, sitting slightly off axis isn't terribly detrimental. Keep em in the corners or give em up guys!

Michael

[Rudy81]

Wow, Kudret, it sounds like you are having some serious problems. My Khorns are at the very edges of the room, about 17' apart. Although there are changes in soundstage and imaging while changing toe-in, they are always there in varying degrees. I use ALK crossovers, but the stock crossovers also provided a nice soundstage and image. The crossovers changed other areas of the sound.

I would first check the possibility of having one of your drivers out of phase. I once had a set of Belles that had a terrible problem. I could never get a good image no matter what I did. I later got a Stereophile test disk and the first few tracks deal with driver phase. My stock mid range drivers were out of phase, although they were seemingly wired correctly. Trust me, I checked and double checked. I swapped the leads on one of my mid drivers, and the change was like I had a new set of speakers. As a matter of fact, what led me to figuire this out is that the test CD played a guitar out of phase when it should have been in phase and vice versa.

My khorns produce very distinct locations for most instruments, depending on the recordings. I do quite a bit of critical listening and love being able to "see" each instrument in space. Now, the soundstage "depth" is a differant story. I wish it were deeper, but a lot of that has to do with room acoustics as well as the distance from the speaker to the wall behind the speakers.

I cannot imagine that your problem is realted to your source equipment. Start by double and tripple checking the wiring on your system, then you may try swapping leads on one of your drivers. That was the only way I was able to find my problem. Of course having a test CD helped a lot.

I wish you lived a little closer, you would be welcome to have a listen to mine and see if you found any differance. Also, I am not sure you are ever going to get a truly "laid back" sound from the horns, I don't think they are likely to give you that laid back, muted, sound I understand you want.

Most importantly, you MUST have the Khorns against a real or false corner. They will sound absolutely terrible without a corner since you are loosing a ton of bass response. To me, that bass response is what makes the Khorn.

Best of luck with the problem, but don't give up.

[Rudy81]

This whole thing about toeing in Khorns is somewhat ludicrous. And the false corners are not terribly effective unless they are much larger and stiffer than what we normally see posted in photos. That is a 90 degree K400 horn, sitting slightly off axis isn't terribly detrimental. Keep em in the corners or give em up guys!

Michael

Well, it may be ludicrous, but in my room there is a noticeable differance in the areas of soundstage and imaging just by playing with the toe-out. My false corners could only be stiffer and more massive if I had used granite counter tops.

I'm not keeping mine in the corners and I won't give them up....ever, I love'em.

[colterphoto1]

Rudy, your false corners look pretty stout, I was referring to the 3/4 ply stand-alone units. Nice setup dude- those ALK's look magical.

Michael

[Rudy81]

Rudy, your false corners look pretty stout, I was referring to the 3/4 ply stand-alone units. Nice setup dude- those ALK's look magical.

Michael

Making those was oh so much fun...! The room is upstairs, so I had to put together the whole thing in the room. Each "wing" took two of us to take upstairs. I estimate they weigh about 60 pounds. The bottom is another 3/4" plywood piece that the Khorn sits on. The "wings" are bolted to the bottom and to each other. If the Khorns produced any more bass I'd be looking for a way to attenuate it.

Thinking about this topic makes me want to ask the following. If you have a pair of La Scalas, would you toe them in 45 degrees? Now, the Khorn has the same drivers, tweeter and mid horn components as the LaS. There must be a noticeable difference when changing the toe-out on a Khorn, just as there is when doing the same with a LaS. This, of course, ignoring the problems with the bass bin not being on a corner. In my case, I built the corners due to room limitations and a poorly placed window. Turns out, for me the advantage is that I can play with the toe-out, and point the top hat toward the sweet spot.

Don't get me wrong guys, I hardly know what I am talking about. I put this post up here to get some ideas. I wish I could hear other Khorn setups, different rooms, different equipment...etc.

[Kudret]

Thank you, Rudy for all the suggestions. I have the AVIA DVD for HT setup. I'll see if it has anything for checking out of phase drivers. In any case, but I will triple check and reverse the driver connections tomorrow.

That's a very impressive HT room.

Kudret

[Kudret]

Thank you, Michael.

OK, I just moved them back and tightly tucked them in the corners. What

I am hearing is a singer with a BIG head and I am not able to localize any

instruments (regardless of where I sit). When I toe-out (is there such a term??)

the speakers while keeping them in the corners, singer's head starts to

shrink to normal proportions.

Kudret

[colterphoto1]

Thinking about this topic makes me want to ask the following. If you have a pair of La Scalas, would you toe them in 45 degrees? Now, the Khorn has the same drivers, tweeter and mid horn components as the LaS. There must be a noticeable difference when changing the toe-out on a Khorn, just as there is when doing the same with a LaS. This, of course, ignoring the problems with the bass bin not being on a corner. In my case, I built the corners due to room limitations and a poorly placed window. Turns out, for me the advantage is that I can play with the toe-out, and point the top hat toward the sweet spot.

Don't get me wrong guys, I hardly know what I am talking about. I put this post up here to get some ideas. I wish I could hear other Khorn setups, different rooms, different equipment...etc.

The 'toe-in' in the case of CW or LS, is with regard to moving the speakers from a perpendicular postion with the front wall, where they are parallel to the side walls. One of the purposes being to eliminate the blurring caused by early reflections coming off the side walls. So a LS at 45 degree angle is considered significantly toed, right?

WIth the Khorn, the speaker is already at its maximized 'toe' position because it sits exactly 45 degrees from both front and side walls. To my ears that's what gives the huge soundstage, because None of the mid horn sound is hitting either wall, it's coming straight at you. So the definition of 'toe' becomes geometrically different with the Khorn. When you adjust it relative to the perfect corner position, you are not only losing bass energy due to loss of the tailboard seal, but you are now possibly blurring the images with early reflections in order to compensate for poor room geometry/seating positon.

I'll stand firm that if you are seated a bit off axis it shouldn't matter that much, but easing the horns from the corner is very harmful to the bass. If there is NO corner, building a very sturdy false one is acceptable. I just think it's shameful to have to go to those extremes if just changing seating position would solve the dilemma.

[Rudy81]

colterphoto1:

I think you and I are saying the same thing. First, the Khorn MUST be in a tight corner or you will loose a large amount of bass response. No questions here.

Now, as far as toe-in for a LaS, Belle, etc, or toe-out for a Khorn, it all has to do with the ability to "aim" the drivers at the sweet spot sitting position. Now, in a very large room, with the Khorns along the long wall, there is a good chance that the sweet spot will be located such that the drivers are firing at you.

In my case, although I have a large room, I chose to use the short wall (20') since I have two tiered seating for movie viewing. In that instance if I had placed the horns in the corner, they would fire at a position well in front of my sitting position. My solution came easy since I already have false corners, I just toed them out to "fire" at my sweet spot.

In my playing around with different angles, from 45 degrees (as in room corners) to 0 degrees, I noticed the aforementioned changes in imaging and sound stage. My whole point is that if you do not have a room that lends itself to the ideal placement, there are gains to be made by having the ability to toe out the Khorns, or at least the top hat section.

BTW, my side walls now have rock wool absorbers, so side reflections are not an issue any more, although the room was rather "live" before.