Hello all,
This is my understanding how linear quadrupole source works for imaging.
Note signals are wired in opposite sides, left speaker receives R signal and vice versa.
In the pic is assumed left channel has a signal and right channel is mute. Left channel signal is transferred only to the left ear while right ear does not receive any signal. The system essentially forms a cross talk cancellation.
Radugazon, is this the way you had in mind?
- Elias
This is my understanding how linear quadrupole source works for imaging.
Note signals are wired in opposite sides, left speaker receives R signal and vice versa.
In the pic is assumed left channel has a signal and right channel is mute. Left channel signal is transferred only to the left ear while right ear does not receive any signal. The system essentially forms a cross talk cancellation.
Radugazon, is this the way you had in mind?
- Elias
Attachments
For a practical matter I should add that the dipole cancellation on the ipsilateral ear does not need to be infinite A few dB difference in the interaural signal amplitude should be enough to shift the image to the side. This is because the interaural delay difference is very short due to the frontal location of the sources, so there is no need for compensation of time-intensity trading.
- Elias
A few dB difference in the interaural signal amplitude should be enough to shift the image to the side. This is because the interaural delay difference is very short due to the frontal location of the sources, so there is no need for compensation of time-intensity trading.- Elias
Hello...
I gave a try to Elias's idea, not followed by a measurement session but by immediate listening comparisons (as always, with a DCX it's remote and a cordless mouse). All at my usual 5 meters listening distance and speakers 3 meters from their back wall.
First impression : widening and airiness of the sound stage, more presence of the voices (by presence, I mean "sculptural effect", not the classic low mid bump). More sparkle too.
Critical listening : s..t ! a violin that is panned on the left is now on the right, as some vocals, it was too beautiful to be true
Thinking of it, this doesn't mean that the idea is fundamentally wrong. Here, my "tweeters" are very close from each other (7 cm) and as the wave guide part is firing outside, it pushes more energy in the room that the dome inner side.
So, the experimentation is not the exact translation of Elias's thoughts.
I gave a try to Elias's idea, not followed by a measurement session but by immediate listening comparisons (as always, with a DCX it's remote and a cordless mouse). All at my usual 5 meters listening distance and speakers 3 meters from their back wall.
First impression : widening and airiness of the sound stage, more presence of the voices (by presence, I mean "sculptural effect", not the classic low mid bump). More sparkle too.
Critical listening : s..t ! a violin that is panned on the left is now on the right, as some vocals, it was too beautiful to be true
Thinking of it, this doesn't mean that the idea is fundamentally wrong. Here, my "tweeters" are very close from each other (7 cm) and as the wave guide part is firing outside, it pushes more energy in the room that the dome inner side.
So, the experimentation is not the exact translation of Elias's thoughts.
Hi,
Another theory
The dipole null is aimed to contralateral ear. And both halves of the linear quadrupole source are tilted a bit. Tilting can happen automatically due to asymmetry of the design.
Again left stereo signal is transferred only to the left ear while right ear receives no signal. Cross talk cancellation happens.
- Elias
Another theory
The dipole null is aimed to contralateral ear. And both halves of the linear quadrupole source are tilted a bit. Tilting can happen automatically due to asymmetry of the design.
Again left stereo signal is transferred only to the left ear while right ear receives no signal. Cross talk cancellation happens.
- Elias
Attachments
To stay on the same subject of strange ideas, it's already a long time that I compare the classical settings to the nightmare illustrated by the screen capture below .
Maybe you can think that my kids have been playing with the DCX !!!
Not at all, I have no explanation behind but it works. Ordinary "widening stereo" uses a global delay on one channel, producing echoes if too much delay, and automatically creating cancellations and reinforcements. It's funny five minutes and boring later.
For this particular kind of settings, I listen and measure (days long process) for obtaining the desired effect without messing up too much the FR (at least incidents that are easy to EQ) and keeping a monolithic step response for the whole system.
I use records that I've heard on the MBL 101 (memory is trusty for sound stage) and some others from research laboratories "I'm now on the left inside of the dummy head...bla bla...".
So, the optimization can be done quite accurately by moving the sliders, localization is almost under control. The only problem is the number of combinations with 6 sliders. Then have to equalise and retest again and again, till something ok.
Of course, this interferes with the speakers placement, with unexpected effects:
I guess this has to do with the delay of the important side reflections (around 16ms, and they hit diffusers) and nothing to do with the localization of the source itself.
Listening to this on normal music, what can I say? It's more beautiful...but different from the pinpointed ideal. The source is not "exactly here", it's more "around here". Ok, it's personal but I feel this light fuzziness more natural. The sound stage is not much wider, but the feeling of involvement spaciousness and airiness (as before with Elias setting) is out of comparison.
Not so bad, but this is the best: the system being EQ the same, something is changing in the voices, the piano...a kind of clarity, of vibration that makes them more detached from the back ground and looking more alive. Really bluffing.
This trick works well on almost any kind of music. Symphonies or little formations are Ok for classic. It adds very little to early jazz stereo, maybe because the R/L separation was exaggerated, but it removes nothing. It works as hell on modern music but I have a few records where it produces a narrowing of the sound stage (probably they produced it with a widening that is canceled by my settings).
As a conclusion, I have been working a lot on time alignment, using all the possible ways (except substractive and FIR), but never got 10% of this. The ambiophonic CTC as emulated by the Audio Mastering suite
is not ok with this system, producing reverb, echoes and reducing the highs.
Psycho acoustic...
.Maybe you can think that my kids have been playing with the DCX !!!
Not at all, I have no explanation behind but it works. Ordinary "widening stereo" uses a global delay on one channel, producing echoes if too much delay, and automatically creating cancellations and reinforcements. It's funny five minutes and boring later.
For this particular kind of settings, I listen and measure (days long process) for obtaining the desired effect without messing up too much the FR (at least incidents that are easy to EQ) and keeping a monolithic step response for the whole system.
I use records that I've heard on the MBL 101 (memory is trusty for sound stage) and some others from research laboratories "I'm now on the left inside of the dummy head...bla bla...".
So, the optimization can be done quite accurately by moving the sliders, localization is almost under control. The only problem is the number of combinations with 6 sliders. Then have to equalise and retest again and again, till something ok.
Of course, this interferes with the speakers placement, with unexpected effects:
- mids units close to each other (60 cm), sound stage is definitively too wide
- mids spaced as 170 cm, sound stage is "realistically" narrowed
I guess this has to do with the delay of the important side reflections (around 16ms, and they hit diffusers) and nothing to do with the localization of the source itself.
Listening to this on normal music, what can I say? It's more beautiful...but different from the pinpointed ideal. The source is not "exactly here", it's more "around here". Ok, it's personal but I feel this light fuzziness more natural. The sound stage is not much wider, but the feeling of involvement spaciousness and airiness (as before with Elias setting) is out of comparison.
Not so bad, but this is the best: the system being EQ the same, something is changing in the voices, the piano...a kind of clarity, of vibration that makes them more detached from the back ground and looking more alive. Really bluffing.
This trick works well on almost any kind of music. Symphonies or little formations are Ok for classic. It adds very little to early jazz stereo, maybe because the R/L separation was exaggerated, but it removes nothing. It works as hell on modern music but I have a few records where it produces a narrowing of the sound stage (probably they produced it with a widening that is canceled by my settings).
As a conclusion, I have been working a lot on time alignment, using all the possible ways (except substractive and FIR), but never got 10% of this. The ambiophonic CTC as emulated by the Audio Mastering suite
is not ok with this system, producing reverb, echoes and reducing the highs.
Psycho acoustic...
Attachments
Thx for the new idea Elias, I'll try to morrow, I have the feeling that this could work .
About interactions with the room, I did an experience using my favorites victims as the picture below : magnet to magnet, once wired in phase opp as a dipole (compound dipole but dipole, there's a deep null and a symmetric front/back radiation) and later as a linear quadri, wired in phase (speakers are too close to have the full omni radiation but there is no null).
Of course, band pass filtered and EQ to have the same FR at 30 ms, except for the dipole dip at 300 Hz that can't be filled.
What happens ? The official wisdom says that dipole interferes less with the room than any omni source. I would agree, but here it's just the opposite. Can be seen on wavelets or CSD, but this image of burst decay is more photogenic.
BTW, if I had to choose a sound more than a chart, the dipole has much more slam but wouldn't be the other one more detailed?
.About interactions with the room, I did an experience using my favorites victims as the picture below : magnet to magnet, once wired in phase opp as a dipole (compound dipole but dipole, there's a deep null and a symmetric front/back radiation) and later as a linear quadri, wired in phase (speakers are too close to have the full omni radiation but there is no null).
Of course, band pass filtered and EQ to have the same FR at 30 ms, except for the dipole dip at 300 Hz that can't be filled.
What happens ? The official wisdom says that dipole interferes less with the room than any omni source. I would agree, but here it's just the opposite. Can be seen on wavelets
or CSD, but this image of burst decay is more photogenic.BTW, if I had to choose a sound more than a chart, the dipole has much more slam but wouldn't be the other one more detailed?
Attachments
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Thx for the new idea Elias, I'll try to morrow, I have the feeling that this could work
.....
Yeah the 2nd theory looks fascinating.
In reality I don't know how symmetrical the dipole is. (I guess not so well on 2 sides of compression driver) So, where and how deep the nulls are would be a question (too good to be true? or needs some more investigation).
OTOH, 2 dipole sources seem the ONLY way to achieve such acoustical XT cancellation.
About the omni vs dipole comparison, the room-interation thing, I think your LQ is not the same as a mono pole omni. LQ has nulls, in some frequency range and source distance the nulls seem disappear but in reality I bet the nulls are there, somewhere, some depth. And it's very likely the opposite motion of the cones get more air load, thus more damping. No?
-----------
As to my own trial, I made 2 changes to the last version.
One was inserting a mid-tweeter in the range of 1.6k~7kHz or so. This section is made of 90-degree conical WG and spaced 1.3m. (on two sides of my TV) I made this for filling the huge gap between tweeter and mid.
The second was to make the tweeters (or, now supertweeters) even closer to each other. I don't have enough drivers to keep the 'quas-omni' arrangement, so they were ordinary front firing setup. But this setting is bad, with too much combing. Several days later, I made this super tweeter a single mono source, also mentioned here roughly: http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-14.html#post2467970
I also mimic the 45degree uptilted arrangement of Stereolith. I think it's cheating somewhat, to make the HF dispersion wide - it stays in some degree of off-axis across a pretty wide listening area. (Like walking around a big sundial and looking at it, it's always relatively tilted and the slope changes very little across a wide veiwing angle...)
OK, how does it sound? Short impression was good. I walked around the room, the tonal balance stayed very stable. As to imaging, it's a mixed bag. Or I should say it's very recording-dependent. More listening and tests are needed.
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Hi Elias,
Considering off center listening, it could happen the opposite effect.
For example, on the sketch in post #25, if another person sit on the right side of that man at the center, then his/her left ear is in the null and right ear in the lobe. This is the opposite of what we want.
So, is it inevitable only a very small sweet spot for such XT cencellation? In addition, this might probably cause some changes in tonal balace when moving around.
Considering off center listening, it could happen the opposite effect.
For example, on the sketch in post #25, if another person sit on the right side of that man at the center, then his/her left ear is in the null and right ear in the lobe. This is the opposite of what we want.
So, is it inevitable only a very small sweet spot for such XT cencellation? In addition, this might probably cause some changes in tonal balace when moving around.
Patrick Bateman his performing some experiments with a similar layout, intended mainly for in-car use. See his webboard:
Audio Psychosis • Index page
Also his threads on the topic in this forum (DIY Audio) and in DIYMA (DIY Mobile Audio).
Sorry I don;t have links at the moment, I'll do a search when I have time.
Audio Psychosis • Index page
Also his threads on the topic in this forum (DIY Audio) and in DIYMA (DIY Mobile Audio).
Sorry I don;t have links at the moment, I'll do a search when I have time.
Yes, as Radugazon has mentioned, the researches and papers are already 10-y-old.
I found another thread here: http://www.diyaudio.com/forums/mult...tribution-experiment-part-1-introduction.html
I found another thread here: http://www.diyaudio.com/forums/mult...tribution-experiment-part-1-introduction.html
Hi,
Yes, usually crosstalk cancelling schemes are for one listener only But that is true for normal stereo as well.
Several persons could be listening on 'tandem'
- Elias
Yes, usually crosstalk cancelling schemes are for one listener only
But that is true for normal stereo as well.Several persons could be listening on 'tandem'
- Elias
Hi Elias,
Considering off center listening, it could happen the opposite effect.
For example, on the sketch in post #25, if another person sit on the right side of that man at the center, then his/her left ear is in the null and right ear in the lobe. This is the opposite of what we want.
So, is it inevitable only a very small sweet spot for such XT cencellation? In addition, this might probably cause some changes in tonal balace when moving around.
Hello,
May I suggest: To know what is really going on measure impulse responses from the speaker to the locations of the Left and Right ears. In practise make two measurements placing the microphone at the listening position +/- 7cm lateral offset from the center axis (if your head is 14cm wide). Maybe no need for the head in place also, to measure the free field. This is to tell how is the wavefield at the listening position and if crosstalk cancellation really takes place.
- Elias
May I suggest: To know what is really going on measure impulse responses from the speaker to the locations of the Left and Right ears. In practise make two measurements placing the microphone at the listening position +/- 7cm lateral offset from the center axis (if your head is 14cm wide). Maybe no need for the head in place also, to measure the free field. This is to tell how is the wavefield at the listening position and if crosstalk cancellation really takes place.
- Elias
To stay on the same subject of strange ideas, it's already a long time that I compare the classical settings to the nightmare illustrated by the screen capture below
Maybe you can think that my kids have been playing with the DCX !!!
Not at all, I have no explanation behind but it works. Ordinary "widening stereo" uses a global delay on one channel, producing echoes if too much delay, and automatically creating cancellations and reinforcements. It's funny five minutes and boring later.
For this particular kind of settings, I listen and measure (days long process) for obtaining the desired effect without messing up too much the FR (at least incidents that are easy to EQ) and keeping a monolithic step response for the whole system.
I use records that I've heard on the MBL 101 (memory is trusty for sound stage) and some others from research laboratories "I'm now on the left inside of the dummy head...bla bla...".
So, the optimization can be done quite accurately by moving the sliders, localization is almost under control. The only problem is the number of combinations with 6 sliders. Then have to equalise and retest again and again, till something ok.
Of course, this interferes with the speakers placement, with unexpected effects:
- mids units close to each other (60 cm), sound stage is definitively too wide
- mids spaced as 170 cm, sound stage is "realistically" narrowed
I guess this has to do with the delay of the important side reflections (around 16ms, and they hit diffusers) and nothing to do with the localization of the source itself.
Listening to this on normal music, what can I say? It's more beautiful...but different from the pinpointed ideal. The source is not "exactly here", it's more "around here". Ok, it's personal but I feel this light fuzziness more natural. The sound stage is not much wider, but the feeling of involvement spaciousness and airiness (as before with Elias setting) is out of comparison.
Not so bad, but this is the best: the system being EQ the same, something is changing in the voices, the piano...a kind of clarity, of vibration that makes them more detached from the back ground and looking more alive. Really bluffing.
This trick works well on almost any kind of music. Symphonies or little formations are Ok for classic. It adds very little to early jazz stereo, maybe because the R/L separation was exaggerated, but it removes nothing. It works as hell on modern music but I have a few records where it produces a narrowing of the sound stage (probably they produced it with a widening that is canceled by my settings).
As a conclusion, I have been working a lot on time alignment, using all the possible ways (except substractive and FIR), but never got 10% of this. The ambiophonic CTC as emulated by the Audio Mastering suite
is not ok with this system, producing reverb, echoes and reducing the highs.
Psycho acoustic...
wheel done !
Elias, I think I will take all your advices very seriously, because the tweeters inversion finally works surprisingly.
It's a synthesis of your two suggestions, but with inverse toeing of the tweeters.
Once the first surprise gone, I did some observations :
All this addresses an issue that I had with this system that was either too wide or too narrow in imaging and delicate to correct. It's not subtle effects but big ones.
Thx Mr Elias.
I have personally no idea about XCT, but can we say that smearing or diminishing the ILD clues is a good idea in central HF system? Are the ITD clues reinforced then? Are them finally more important ?
Wow, this is exactly the theory proposed by the Stereolith creator.
Just in case, I have been spacing my tweeters of 17 cm, the size of my head.
Elias, I think I will take all your advices very seriously, because the tweeters inversion finally works surprisingly.
It's a synthesis of your two suggestions, but with inverse toeing of the tweeters.
Once the first surprise gone, I did some observations :
- listening to the tweeters alone, the reverse option shifts some informations (fast transients mainly), but not everything. I was never been aware of this: they behave almost as a mono source, this confirms CLS's experiments.
- listening to the mids alone, I must say that the subjective HF elements are very weak (say cymbals, violins...).
- but listening to the whole system, the same lateral sources are localized further outside of the center tweeters (around 15°/20°) and this time always on the good side.
- and the sound gets more chiseled, in the fashion the out of phase settings do.
All this addresses an issue that I had with this system that was either too wide or too narrow in imaging and delicate to correct. It's not subtle effects but big ones.
Thx Mr Elias.
I have personally no idea about XCT, but can we say that smearing or diminishing the ILD clues is a good idea in central HF system? Are the ITD clues reinforced then? Are them finally more important ?
Wow, this is exactly the theory proposed by the Stereolith creator.
Just in case, I have been spacing my tweeters of 17 cm, the size of my head.
Attachments
Wow, that's totally unimaginable.
However,
1. The actual behavior of your HF section is probably beyond "theoretical dipole", as its asymmetry of front/rear radiations.
I vaguely remember there was a thread (can't find now) about simulations of a naked cone driver (not the same as yours, though). In which, the sim shows a severe asymmetry of front/rear lobes above a certain frequency - the magnet structure and imperfect bascket of the cone driver is a big obstacle to HF sound, thus the asymmetry...
In your case, the front/rear radiations of [phase plug - WG] vs [bare dome] are surely a lot different from a naked cone driver, but I suppose it's almost equally difficult to predict.
OTOH, the (perfect) dipole nulls play a key role in the theories brought up by Elias, I'm afraid we are shooting in the dark here.
2. One step further, the 2 channels of the HF section form a double-unpredictiable quadruple ! And given the close positioning, may I say they might probably perform very close to one (mono) omni source ! (?)
The second point might probably very important. In my own experiment, 2 close-positioned (ordinarily front firing) tweeters sound odd -- listening at the center, the imaging is very sharp; off center just a little, it's suddenly unfocused. Not entirely 'collapsed', but the contrast of [clear-cut/fuzzy] when moving is very obvious and annoying. The tonal quality is also changing. I don't like it.
Interestingly, my previous 'quasi-omni' tweeters seemed to side step this problem somehow, although they are equally spaced.
Now my mono super tweeter setup avoids that combing issue altogether. It's very stable.
However,
1. The actual behavior of your HF section is probably beyond "theoretical dipole", as its asymmetry of front/rear radiations.
I vaguely remember there was a thread (can't find now) about simulations of a naked cone driver (not the same as yours, though). In which, the sim shows a severe asymmetry of front/rear lobes above a certain frequency - the magnet structure and imperfect bascket of the cone driver is a big obstacle to HF sound, thus the asymmetry...
In your case, the front/rear radiations of [phase plug - WG] vs [bare dome] are surely a lot different from a naked cone driver, but I suppose it's almost equally difficult to predict.
OTOH, the (perfect) dipole nulls play a key role in the theories brought up by Elias, I'm afraid we are shooting in the dark here.
2. One step further, the 2 channels of the HF section form a double-unpredictiable quadruple ! And given the close positioning, may I say they might probably perform very close to one (mono) omni source ! (?)
The second point might probably very important. In my own experiment, 2 close-positioned (ordinarily front firing) tweeters sound odd -- listening at the center, the imaging is very sharp; off center just a little, it's suddenly unfocused. Not entirely 'collapsed', but the contrast of [clear-cut/fuzzy] when moving is very obvious and annoying. The tonal quality is also changing. I don't like it.
Interestingly, my previous 'quasi-omni' tweeters seemed to side step this problem somehow, although they are equally spaced.
Now my mono super tweeter setup avoids that combing issue altogether. It's very stable.
After this novelty, I did a fast directivity control of the horizontal room response (30 ms) by orbiting around the tweeters, the mike positioned with a cable, both channels firing.
At the listening distance same response from axis to 45°.
After, the profile of the curve stays the same but the level raises up progressively till 6 dB more on the WG axis.
No peak, no dip with this window.
At this point, if I measure the response of the opposite tweeter, it's response is exactly the same than both channels on axis, so much that I believed I did a mistake.
Have to think of it...
Going further, the levels goes down gradually, but then there is the wall.
Same process at 65 cm :
the axis curve keeps the same general shape but with ripples.
Measured from the back axis, it's a camel: dip at 3700, bump at 2000.
Measured in the WG axis, smooth text book curve with the only good impulse available. Again, no lobing, smooth transition.
The levels raise up of 10 dB on the WG side, and it's the only place where I see the 20000 Hz. Here, one channel or both channels makes no difference, but on the listening axis 65 cm, the level go up of 6dB when both channels run.
Conclusion:
As I mentioned and as you said: alone, it sounds more as a mono source. You use a mono tweeter and get satisfied. Same for stereolith. Patrick Bateman is happy with centered tweeters in his car...slowly but surely we are going to invent the central channel of HT
.
At the listening distance same response from axis to 45°.
After, the profile of the curve stays the same but the level raises up progressively till 6 dB more on the WG axis.
No peak, no dip with this window.
At this point, if I measure the response of the opposite tweeter, it's response is exactly the same than both channels on axis, so much that I believed I did a mistake.
Have to think of it...
Going further, the levels goes down gradually, but then there is the wall.
Same process at 65 cm :
the axis curve keeps the same general shape but with ripples.
Measured from the back axis, it's a camel: dip at 3700, bump at 2000.
Measured in the WG axis, smooth text book curve with the only good impulse available. Again, no lobing, smooth transition.
The levels raise up of 10 dB on the WG side, and it's the only place where I see the 20000 Hz. Here, one channel or both channels makes no difference, but on the listening axis 65 cm, the level go up of 6dB when both channels run.
Conclusion:
- it's still omni in the front space but excites more the room on the sides and the back
- there is no horizontal hard lobing that I've seen
- the reflections don't add coloration on a specific incidence, so it's easy to EQ
- a LQ opened of 30° is not killed yet.
As I mentioned and as you said: alone, it sounds more as a mono source. You use a mono tweeter and get satisfied. Same for stereolith. Patrick Bateman is happy with centered tweeters in his car...slowly but surely we are going to invent the central channel of HT
.Just a little reminder, the mono portion of my trial (up to now) is only above 7~8kHz;
Under that, and down to about 2kHz, a stereo pair are separated by 1.3m;
Under 2kHz, sources are separated by more than 3m.
(all 1st order filters, so a lot of overlap, though)
So, what I got must be very different from yours. I remember your [mid-tweeter/tweeter MTM module] works above 1kHz or so -- that's a half of audible spectrum !! And the conditions of radiation pattern and space are very different, too.
Under that, and down to about 2kHz, a stereo pair are separated by 1.3m;
Under 2kHz, sources are separated by more than 3m.
(all 1st order filters, so a lot of overlap, though)
So, what I got must be very different from yours. I remember your [mid-tweeter/tweeter MTM module] works above 1kHz or so -- that's a half of audible spectrum !! And the conditions of radiation pattern and space are very different, too.
Have been listening more and more, I ran into a dilemma
Close positioned or now mono tweeter has a strong point of spaciousness, especially in the depth. Images seem always appear behind the speakers. The presentation is more of 'you are there', instead of 'they are here' -- a 'tradition' of high efficiency horn system (what I had before).
Images in the soundstage are well defined, individual instruments or vocals have their right positions or even shapes and sizes. And I got a feeling that sources seem to have 'haloes' or they're slightly glowing -- there's soft and tender 'atmasphere' around each of them and among them. In addition, such wonder can be maintained in a very large listening area. In extreme off center listening positions -- at the side of the speaker, imaging collapses (of course) while tonal balance stay very stable.
I'm not sure how the images can be projected and focused beyond the tweeters (no special signal process here, only ordinary 1st order filters). Those sounds coming with very high frequecy overtones (attacks of percussions, strings...) are indeed formed far outside of the tweeters when call for, but with a condition...
---- the sound must have its own 'body' in relatively lower frequencies (the fundamentals).
When the sound is purely HF, then comes the problem. Jazz piano trio is one of my favorite forms of music. The drum set is often arranged at one side of the stage (-- almost always on the right in one of my favorit trio, Keith Jarret Trio). I can 'see' the piano, bass, drums at thier correct positions, but when the cymbals are hit, almost always, they appear around the center -- detached from the whole drum set.
Sometimes, a large ride cymbal is softly hit (or hit by a stick with felt ball), there's larger proportion of lower fundamental. This note would come back to its correct position with the whole drum set. Such effect is annoying, be it CD or DVD.
Sigh~ What a pity !
By the way, I made the supertweeter in vertical face to face 'quasi-omni'. And I've tried arranging the midtweeter horns to side or up firing (like the ears of Shrek). Shrek type radiation makes a very spacious sound field, but is not helping the 'positioning' problem of the HF images. And it's too much 'atmosphere' with too less 'body'.
I've also tried "R-L" and "R-L" signal on the midtweeters by series connecting. The sound seems clearer, but could not solve that problem, either.
So, it's not perfect yet. The journey goes on.
Close positioned or now mono tweeter has a strong point of spaciousness, especially in the depth. Images seem always appear behind the speakers. The presentation is more of 'you are there', instead of 'they are here' -- a 'tradition' of high efficiency horn system (what I had before).
Images in the soundstage are well defined, individual instruments or vocals have their right positions or even shapes and sizes. And I got a feeling that sources seem to have 'haloes' or they're slightly glowing -- there's soft and tender 'atmasphere' around each of them and among them. In addition, such wonder can be maintained in a very large listening area. In extreme off center listening positions -- at the side of the speaker, imaging collapses (of course) while tonal balance stay very stable.
I'm not sure how the images can be projected and focused beyond the tweeters (no special signal process here, only ordinary 1st order filters). Those sounds coming with very high frequecy overtones (attacks of percussions, strings...) are indeed formed far outside of the tweeters when call for, but with a condition...
---- the sound must have its own 'body' in relatively lower frequencies (the fundamentals).
When the sound is purely HF, then comes the problem. Jazz piano trio is one of my favorite forms of music. The drum set is often arranged at one side of the stage (-- almost always on the right in one of my favorit trio, Keith Jarret Trio). I can 'see' the piano, bass, drums at thier correct positions, but when the cymbals are hit, almost always, they appear around the center -- detached from the whole drum set.
Sometimes, a large ride cymbal is softly hit (or hit by a stick with felt ball), there's larger proportion of lower fundamental. This note would come back to its correct position with the whole drum set. Such effect is annoying, be it CD or DVD.
Sigh~ What a pity !
By the way, I made the supertweeter in vertical face to face 'quasi-omni'. And I've tried arranging the midtweeter horns to side or up firing (like the ears of Shrek). Shrek type radiation makes a very spacious sound field, but is not helping the 'positioning' problem of the HF images. And it's too much 'atmosphere' with too less 'body'.
I've also tried "R-L" and "R-L" signal on the midtweeters by series connecting. The sound seems clearer, but could not solve that problem, either.
So, it's not perfect yet. The journey goes on.
Attachments
Interesting...
If the gap between the speakers is the 60° layout issue, the always centered Hf is the issue of our layout when the ITD mid clues are not strong enough to get the lock.
Over delaying the Hf for creating a precedence effect is not working, but there's something else to do...
go to the ISVR dl page and dl tracks 1,2,3. These tracks are not intended for normal systems, dunno what kind of matricing they have, but they are very revealing and easy to interpret.
Maybe the 2 will show "all in the center" instead of "left". Why ?
Long time I have been self debating with this, because the few settings correct on it where obviously better imaging. I know now that this test needs a lot of energy in the mid low for giving the lateralization, ITD clues, but this can affect the tonal balance.
I discovered later that retarding R (from 0.5 to 1.8 ms, following the filter used) re-establishes the lateralization without affecting that much the balance.
By experience, these settings sound wider, on normal tracks, without the HF stuck in the middle.
So, we are speaking of tweeters since a while, but mids and low have a big importance in the HF restitution. Try abusive overlapping with EQ, try all the possible toeings, and maybe delaying mechanically one of the mids...just to see, because it's not sure that the global result will be satisfying on real music.
If the gap between the speakers is the 60° layout issue, the always centered Hf is the issue of our layout when the ITD mid clues are not strong enough to get the lock.
Over delaying the Hf for creating a precedence effect is not working, but there's something else to do...
go to the ISVR dl page and dl tracks 1,2,3. These tracks are not intended for normal systems, dunno what kind of matricing they have, but they are very revealing and easy to interpret.
Maybe the 2 will show "all in the center" instead of "left". Why ?
Long time I have been self debating with this, because the few settings correct on it where obviously better imaging. I know now that this test needs a lot of energy in the mid low for giving the lateralization, ITD clues, but this can affect the tonal balance.
I discovered later that retarding R (from 0.5 to 1.8 ms, following the filter used) re-establishes the lateralization without affecting that much the balance.
By experience, these settings sound wider, on normal tracks, without the HF stuck in the middle.
So, we are speaking of tweeters since a while, but mids and low have a big importance in the HF restitution. Try abusive overlapping with EQ, try all the possible toeings, and maybe delaying mechanically one of the mids...just to see, because it's not sure that the global result will be satisfying on real music.
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