[ctviggen]

If you had to characterize position of the (sound) image projected by the RM40s, where would you place the image?  I ask because the image for me appears to be above the level of the tweeter, almost near the top of the speaker.  For critical listening, I put two Realtraps microtraps between the speakers. I have a RPTV, stand, and RM30C on top of the RPTV.  I'm wondering if the RM30C is reflecting more sound than the RPTV, thus making the image appear "taller" than it normally would be.  The image also appears to be behind the RM40s, usually by a few feet at least.  My RM40s come out from the RPTV by around two feet or so, although the image appears even further back.   

So, where would you say the image resides for your RM40s? 

[Early B.]

I'm very interested in the answer to this question as well.

I have a pair of Tower II SE's and the image is pinpointed less than three feet off the ground and below tweeter level. I've been trying to figure out how to increase the image height. Since I sit 9 ft. away from the speakers, I figured I had no alternatives.

[warnerwh]

My room is LEDE with the dead end being the stereo end. Imaging is centered and about even with the middle of my speakers. It's also maybe 2-3 feet back.  Singers will be just a bit above the center of the speakers usually, sometimes though they can be like they''re standing in here.

Your theory about your center speaker is interesting to me. I built two sealed subs which are placed on the outside of each 40 but baffles are even.  Since I put them there a lot more sound emanates from the outside of the speakers. I built one sub first and noticed it then on the one side which helped inspire me to do another sub to balance the sound out. The subs are 20" wide and 30" tall, so they're fairly large.

[John Casler]

Great Question, to which there is no "exact" answer.

Imaging is caused by, related to, and affected by many elements in the system, room, and set up.

Additionally, the RM40, has had many changes from its initial production (2002) until the present.  So each of those changes can also affect the small components in the images.

The most palpable of images will be thrown when several things are present or not present:

1) Low Noise - If there is noise in the system, even if it is low level, that "obscures" the edges, contrast and texture of the images produced

2) Low Room Reflection - This is the same as noise, since it is fogging and obscuring to the sound that actually reaches your ears  It adds another component of deterioration called "comb filtering".  That is when a reflected sound, bounces back through the "direct sound" you hear coming from the speaker, and the interaction of these sonic energies, cause an effect, whereby what you hear has been "filtered" by passing through the reflected sound

3) Phasing - It is important to imaging to make sure the system and speakers are in matching phase.  If one component is mismatched to phase, the image will "disperse" and be quite unclear.

4) Recordings that have good imaging are also required since it cannot be reproduced if it is not recorded properly.  Also key to imaging is not just the balanced magnitude of the signal between the two speakers to "place" an image in the correct position, but the associated reflected and ambient sounds of the venue, which can easily be obscurred if they have to compete with the "ambiance" of your listening room.

That said, the imaging of the RM40 will differ significantly with the field of the listening position.  Nearfield may make for taller imaging, and a more immediate (close) image of life sized or larger.  Detail will be greatest to add to that sonic "closeness", and image sharpness.

Moving more farfield, will likely yield a similar adjustment in imaging as moving further back in the hall or venue.  You will find the images reduce in height and recess further back between or behind the speakers.  Detail will also reduce slightly just as in real life, adding to the accurate portrayal.

Also particular to the RM40 and RM v60 is the fact that because of their height, and the height of the neopanels, they tend to throw a "larger" images than the stand mount 626, or the slightly shorter RM30s.

The Newer RM40's with the improved midwoofer and the higher x-over point will also image slightly differently than their predecessors, creating a larger and fuller soundstage and imaging.

And regarding things between the speakers like RPTV and such: These things have a tendency to create image fogging and draw.  That is, they can create a reflection that will "fog" the images by creating two origins with slightly different positions, and or they can draw the image, and even "stretch" it in certain frequencies depending on the reflective properties (frequencies) of the surface.

By "drawing" I mean it can pull the image left or right a bit.

These are just a few thoughts.  I might come up with a couple more later.

[Early B.]

Damn, John, thanks for the thorough response! Looks like I have virtually every imaging issue you mentioned.

When you talked about "low room reflection," do you mean a room with a low ceiling?

[John Casler]

Damn, John, thanks for the thorough response! Looks like I have virtually every imaging issue you mentioned.

When you talked about "low room reflection," do you mean a room with a low ceiling?

Yeah, I wrote all that and said there is really no complete answer. 

By "low room reflections". I was talking about "any and all" sound that you hear, that is NOT coming directly from the speaker uninterupted to your ear.

In a "pure imaging sense" any sound not from the source could modify your perception of what was recorded (and of course that depends on the recording quality and type)

[ka7niq]

When I substituted Dual mid woofers INSTEAD of one mid woofer and one Mega Woofer, the imaging was dead centered.
However, probably because of either the wide driver spacing of the woofers, and the resulting interference patterns, and/or the slow slope crossover, I could not make them sound right.

In the RM 40's, the drivers are staggered electrically or mechanically and roll off differently.
Thus, the top woofer has the considerable job of reproducing a lot of the music.

I have ordered the mid woofer update for my RM 40's, in hopes of not having to run the midrange levels way down below 12 o'clock to get the warm sound I prefer, in my room.

When I went much below 12 o'clock, the top woofer called "attention" to itself by having images "jump" up to it!

And, if I ran the midrange levels up higher, the sound was too thin for my room and linking.

I am hoping the mid woofer upgrade and higher crossover point will warm up the sound considerably ?

I never did TRY my electronic crossover with the two mid woofers in my RM 40's.
I did the math on the space between the upper and lower woofers, and it's relationship to a 1/2 or 1/4 wavelength at what frequency.

I was told by several familiar with Line Array and speaker theory that they felt that a steeper crossover may be a great asset on the woofers.

One "problem" these "experts" pointed out to me was that in it's stock configuration, the RM 40 is an unusual design.

Unusual in that it is not a line array over it's whole range.

The midrange section is a line array of sorts, but the woofer, lower midrange section is not.

Actually, the top midwoofer, according to them, acts as a point source, and the midrange panels act as a line souece!

What this means is that in the far field, you have different radiation patterns in different frequency ranges!

As we all know, a line source does not fall off in level as much as a point source.

So, once the top woofer stops reproducing the same frequency as it's lower woofer, it is alone, and begins to act as a point source.

True, room effects can SOMETIMES "fill in" for this, and this "problem" will not be evident in all rooms, but it sure is, in mine.

I think the increased efficiency is an admirable attempt by Brian to correct this for customes where it IS a problem.

I do not hear this problem as much in the other local OLDER RM 40's.

I did not hear it at Kevins at all, and at my friend Mike's. as much as I do in my room.

I STILL haven't "given up" completely on using the same woofer pair with a steeper crossover, but I just got tired of playing.

I trust Brian, and think the new midwoofers may be my answer.

[John Casler]

When I substituted Dual mid woofers INSTEAD of one mid woofer and one Mega Woofer, the imaging was dead centered.
However, probably because of either the wide driver spacing of the woofers, and the resulting interference patterns, and/or the slow slope crossover, I could not make them sound right.

In the RM 40's, the drivers are staggered electrically or mechanically and roll off differently.
Thus, the top woofer has the considerable job of reproducing a lot of the music.

I have ordered the mid woofer update for my RM 40's, in hopes of not having to run the midrange levels way down below 12 o'clock to get the warm sound I prefer, in my room.

When I went much below 12 o'clock, the top woofer called "attention" to itself by having images "jump" up to it!

And, if I ran the midrange levels up higher, the sound was too thin for my room and linking.

I am hoping the mid woofer upgrade and higher crossover point will warm up the sound considerably ?

Chris,

Have you tried the "sonic director" tweak?

I developed it back when I had a pair of RM40s very much like yours, although I didn't have the same thing you are describing.  A quick search will likely find the description.

It may allow you to run the neos higher and get more direct response from your upper woofer while reducing the ceiling interaction which is likely your problem.

I was told by several familiar with Line Array and speaker theory that they felt that a steeper crossover may be a great asset on the woofers.

One "problem" these "experts" pointed out to me was that in it's stock configuration, the RM 40 is an unusual design.

Unusual in that it is not a line array over it's whole range.

The midrange section is a line array of sorts, but the woofer, lower midrange section is not.

Actually, the top midwoofer, according to them, acts as a point source, and the midrange panels act as a line souece!

Hmmmm. . . .the problem with experts is?   

Chris, while I am not a speaker designer, I'm not sure a driver covering such low frequencies (155hz down) can be considered to act as much of a "point source".

Additionally, and interestingly enough, even though a line of neopanels appears to be and certainly might be considered a "line source" it, to the ear is a "point source" in  that the ear, because of the radiation pattern of each driver, only hears one or two panels at most, due to the directionality of the drivers and the frequencies they produce.

That is your ear does not hear the highest and lowest Neopanels, but it hears the efficiency the design creates to the couple drivers you do hear.

Now this is also affected by the listening distance, and the more farfield the more you may hear the upper and lower neos.

But the "line" does assume some of the other charachtersistics of a line and the sound will not decrease in SPL as quickly as higher dispersion drivers.

As we all know, a line source does not fall off in level as much as a point source.

So, once the top woofer stops reproducing the same frequency as it's lower woofer, it is alone, and begins to act as a point source.

Some how I think what your describing is not related to "point source" again as above due to how low the frequencies are.

Keep in mind all the newer RM40s have a higher X-over to the Midwoofer (some 220 -280hz) if that driver were acting as a point source, it would be exacerbated by the higher frequencies and it is not.

I might think you might be hearing some type of reflection or combing of some type and the "sonic director" tweak, and or moving your listening position and or speaker position might help.

True, room effects can SOMETIMES "fill in" for this, and this "problem" will not be evident in all rooms, but it sure is, in mine.

I think the increased efficiency is an admirable attempt by Brian to correct this for customes where it IS a problem.

I do not hear this problem as much in the other local OLDER RM 40's.

I did not hear it at Kevins at all, and at my friend Mike's. as much as I do in my room.

I STILL haven't "given up" completely on using the same woofer pair with a steeper crossover, but I just got tired of playing.

I would bet the listening/room geometry at Kev's and Mike's is different.

Let us know how you fair.

[ka7niq]

Thanks for the tip John.
I do have a weird listening arrangement compared to Kevin and Mike.
My room is a converted Car Port with a very low suspended ceiling.

I somehow missed the sonic director tweak, but it looks interesting, now that I look at it.

I am really looking foreward to getting the new midwoofers.

There seems to be total agreement among RM 40 owners that it is the best upgrade for the money.

This, plus the raised crossover point may just do the trick.

Ya know, speaker voicing is a personal preference.

I like the "old schol" British sound John, warm, thick, and lush.

Not boxy or totally colored, but warm and rich with punchy mid bass.

I find this to be a more forgiving tonal balance.

I listen to what I like to listen to, and will not be "held hostage" by a speaker that ONLY sounds it's best on Telarcs and Sheffields, etc, etc.

I will gladly trade SOME transparency for a warmer, more forgiving balance.