^ could you be more specific or quote the initial message you are refering to please TNT?
If it was to my comment:
Point source - Wikipedia
Point sources | Sound Waves
I could ilustrate my point with polar plots of different diameter drivers and their point of beaming.
This is wavelength to physical size of driver related. Same thing happen for a ( real world, not theorical ideal) 'point source': this can only be true below a defined frequency related to driver diameter.
If it was to my comment:
Point source - Wikipedia
Point sources | Sound Waves
I could ilustrate my point with polar plots of different diameter drivers and their point of beaming.
This is wavelength to physical size of driver related. Same thing happen for a ( real world, not theorical ideal) 'point source': this can only be true below a defined frequency related to driver diameter.
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I would be interested in your implementation of Seas coax.
I built the Seas Loki kit with the clear cone and wasn’t too stoked on it to be honest.
I have a pair of Vandersteen VCC’s that are much better.
Does Gradient’s schematic appear anywhere?
This is called engineering and you just have to do the best you can - I used to have this beaten into me by the first engineer I worked with post Uni, so it's a favourite expression. Good synopsis on the whole.
I quite like coaxes overall, but one of the things people get wrong is trying to make a full range 2 way out of them. Keep all of the midbass out of the cone and you improve some issues enough, with some DSP loving to make very nice speakers out of common pro drivers.
When I first started doing this with Tannoys in the 90s (analogue XO then) I was a pariah in the Tannoy community, but mine sounded and measured much better.
I have Lambda Unitys in my mains and Faital 8HX300 as the MF/HF in the surrounds (15" MB), all speakers active DSP, and they're good enough for my needs not to want to bother with much else. I have a few spare drivers and after the move might make 15/8c/15 enclosures for the surrounds.
johnnyk9, I don't know a resource for Gradient crossovers, but general info and tests are available. Revolution has several versions with different xo, the one tested by Stereophile seems to have LR4 acoustic slopes.
Gradient story - Gradient Labs Oy
Golden Ear winner Gradient Revolution
Finnish Gradient 1.4 loudspeaker
Gradient Five bookshelf speaker
Gradient Revolution loudspeaker Measurements | Stereophile.com
http://highfidelity.pl/@main-843&lang=en
Gradient story - Gradient Labs Oy
Golden Ear winner Gradient Revolution
Finnish Gradient 1.4 loudspeaker
Gradient Five bookshelf speaker
Gradient Revolution loudspeaker Measurements | Stereophile.com
http://highfidelity.pl/@main-843&lang=en
12FCX76 in about 180L boxes tuned with two ports (about 35 hz when the other is stuffed). I may have a problem with the driver phases, had to measure when I get a new measurement microphone. Also the listening position seems to be quite critical, the balance shifts to the closer speaker breaking stereo image if not listening in the mid position (and I don't have balance pot in my amp).
^ yes the shift of image to closest loudspeaker is one of the drawback of 'point source' loudspeakers ( whichever the type).
Coupled to the rising directivity with freq and users who don't get you have to listen a bit offaxis gave the reputation i've heard about Tannoy when in studio ( harsh high and critical listening spot).
Some dislike it. As i perform critical listening at a defined spot without moving too much it doesn't bother me this much.
Coupled to the rising directivity with freq and users who don't get you have to listen a bit offaxis gave the reputation i've heard about Tannoy when in studio ( harsh high and critical listening spot).
Some dislike it. As i perform critical listening at a defined spot without moving too much it doesn't bother me this much.
Toe in the speakers to cross in front of the listening spot should help on this wandering image issue, even with very beamy speakers it should stabilize image a little at least.
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In my case it doesn't: if you make them x in front of listening spot you start to illuminate the front wall and issues arise ( the loudspeakers are close to front wall)... it makes listening position even more critical and one person only ( which can be great as nearfield if far from front wall).
It will depend of the type of coax and room too: with directivity control and a 90* cone it make much sense to have them to cross on the backwall ( behind your back) and listen off axis: it offer a much wider listening spot ( if room allow of course).
With 'Cabasse' style or other with very wide beam it's even different in rendering, same with fullrange...
The image is not wandering, it's just you are aware when you moove from equilateral center. With more conventional layout loudspeakers the 'blur' between the differents drivers position make it less obvious ime.
You withstand it or not long term. Like Celef's comment about his preference for coax irt lobing issues. Pick your poison. 😉
It will depend of the type of coax and room too: with directivity control and a 90* cone it make much sense to have them to cross on the backwall ( behind your back) and listen off axis: it offer a much wider listening spot ( if room allow of course).
With 'Cabasse' style or other with very wide beam it's even different in rendering, same with fullrange...
The image is not wandering, it's just you are aware when you moove from equilateral center. With more conventional layout loudspeakers the 'blur' between the differents drivers position make it less obvious ime.
You withstand it or not long term. Like Celef's comment about his preference for coax irt lobing issues. Pick your poison. 😉
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The logic says crossing in front of listening position is far better. There are two main phenomenon that affect the image shifting that can either magnify each other (unstabilize) or compensate for each other (stabilize) as one moves to the side of the listening spot. The phenomenon are distance to each loudspeaker and being on or off axis, both affect how loud the speaker appears to the ear. Image shifts to the louder one.
If the speakers are toed in to cross behind the listening position these two phenomenon magnify each other and image shifts to the closest speaker with small head movement. As you move your head to left you are now closer to left speakers on-axis and further out in the right speaker off-axis AND closer to the left speaker and further from the right speaker. Little physical movement yields longer movement in "hearing distance", how loud each speaker appears, and the image shifts from center to the nearest speaker and locks it there.
If you toe in the speakers to cross in front of the listening position instead these two things compensate for each other. Move head to left and you move more off axis to the nearest left speaker and more on axis to the further right speaker. The "hearing distance" moves less than the head and the image should be stable. One would need to stand up and take few steps to lock the image to either speaker in comparison just tilting the head?🙂 What do I know, haven't been listening to stereo long time. Mono rocks, solid locked image!😀
Not sure which could be more annoying, early reflections or wandering image, I guess both. One should deal with both by controlling directivity and room acoustics and toe in front of the listening position. Both will steer towards better sound experience.
If the speakers are toed in to cross behind the listening position these two phenomenon magnify each other and image shifts to the closest speaker with small head movement. As you move your head to left you are now closer to left speakers on-axis and further out in the right speaker off-axis AND closer to the left speaker and further from the right speaker. Little physical movement yields longer movement in "hearing distance", how loud each speaker appears, and the image shifts from center to the nearest speaker and locks it there.
If you toe in the speakers to cross in front of the listening position instead these two things compensate for each other. Move head to left and you move more off axis to the nearest left speaker and more on axis to the further right speaker. The "hearing distance" moves less than the head and the image should be stable. One would need to stand up and take few steps to lock the image to either speaker in comparison just tilting the head?🙂 What do I know, haven't been listening to stereo long time. Mono rocks, solid locked image!😀
Not sure which could be more annoying, early reflections or wandering image, I guess both. One should deal with both by controlling directivity and room acoustics and toe in front of the listening position. Both will steer towards better sound experience.
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You also suggest directivity may be the issue. The audibility of different spacings or crossover frequencies isn't considered. It isn't clear what level of dependency there is on coincident sources here.
In any case, while the image may move around as you do, it shouldn't "break".
Tmuikku in my case early reflections from front wall are annoying and as i don't use them for their intended use ( nearfield) i find the option i choosed as best compromise ( it helps to have highs in the back of room where there is a table where family seat...).
Your comment about toe in is right with constant directivity waveguide/horn. With coax of older gen ( like mine) this is not always the case: most of the time they behave like typical horn: they beam a bit all along the waveguide range ( abit like fullrangers but less severe and not at same freq).
This is why there is a rise in high on axis with this kind of coax. And as you don't want to listen to them on axis because of the ragged high thanks to diffraction...
I'm really interested in the newer gen which exhibit more constant directivity behavior in the 'important range' ( to me, up to ~10k like Kef, Bms,..) to compare and see if it brings something more to it.
I've found with the coax i've had at home positioning and toe in are indeed more touchy than my 'conventional' threeway and two ways. But once ok i find rendering much more rewarding.
Allen, yes the image doesn't break with the coax. With the threeway it does. Yes ER are at play but not only with them ( 3ways).
I don't get your comment about audibility of different spacing xover. Could you elaborate a bit please?
Your comment about toe in is right with constant directivity waveguide/horn. With coax of older gen ( like mine) this is not always the case: most of the time they behave like typical horn: they beam a bit all along the waveguide range ( abit like fullrangers but less severe and not at same freq).
This is why there is a rise in high on axis with this kind of coax. And as you don't want to listen to them on axis because of the ragged high thanks to diffraction...
I'm really interested in the newer gen which exhibit more constant directivity behavior in the 'important range' ( to me, up to ~10k like Kef, Bms,..) to compare and see if it brings something more to it.
I've found with the coax i've had at home positioning and toe in are indeed more touchy than my 'conventional' threeway and two ways. But once ok i find rendering much more rewarding.
Allen, yes the image doesn't break with the coax. With the threeway it does. Yes ER are at play but not only with them ( 3ways).
I don't get your comment about audibility of different spacing xover. Could you elaborate a bit please?
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Should work well for non constant directivity speakers as well as long as on-axis is louder than off-axis, which should be the case 99%. Constant directivity adds benefit of more stable frequency response, "sound color", and image should be even more stable. Nearfield can be a different thing, so what ever works 😉
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Different issues have differing audibilities, usually including varying factors such as frequency, level or degree of the problem.
TMuikku well the way i would expect constant directivity to change would be ER related: as you point less spectral deviation from them so they should be less bothersome.
It could help give the feeling to be in a seat in a front row too if room size allow ( try a reverb with tail totally cut only ER, set them up @-10db and 10ms and set equal level of rvb and direct sound ( simulate critical distance). Run some music through it and feel the effect to be expected.
Discovered this when playing with different room layout proposition 'simulation'. The one i describe is more or less what could be expected from Wayne Parham ( Pi Speakers) describe in it's white paper.
😉
Allen ok got it. As i played with crossover freq and type of the 3way, listened to them ouside and it didn't really changed this feel i came to conclusion it is indeed related to acoustic issues them being either from the box and the driver layout, their location, the room or a mix of all this and maybe more.
It could help give the feeling to be in a seat in a front row too if room size allow ( try a reverb with tail totally cut only ER, set them up @-10db and 10ms and set equal level of rvb and direct sound ( simulate critical distance). Run some music through it and feel the effect to be expected.
Discovered this when playing with different room layout proposition 'simulation'. The one i describe is more or less what could be expected from Wayne Parham ( Pi Speakers) describe in it's white paper.
😉
Allen ok got it. As i played with crossover freq and type of the 3way, listened to them ouside and it didn't really changed this feel i came to conclusion it is indeed related to acoustic issues them being either from the box and the driver layout, their location, the room or a mix of all this and maybe more.
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The one in my avatar and discussed with Spladski: Tannoy System800 passive.
They are not flawless but they are on play 90% of time since i have them... I hesitate to use the driver in a different build though: as they are relatively 'compact' ( bulk) and ok to me, and i definitely like bigger diameters... maybe put them in a closed box and add a pair of twelve for 250hz and lower, a la Seaton's sound Catalyst? Not sure if it would bring what i liked in the 12" and 15" i liked. Probably way better however: this kind of drivers begs for being used in three way with direct radiating driver of coax relief from bass duties imho ( and already said by other members). Few are ok for 2ways use imho.
I've had Cabasse goelette 500 ( with a two way cabasse coax from 1k and up, with tweeter, predecessor to the threeway they use now), System1200 and 800 in the last 4 years.
I liked them all but prefered the 1200 by wide margin. More directivity control and lower in freq and i prefer the sound of compression driver to tweeters.
My absolute ref is Tannoy DMT15mk2 used in wall ( for coax but i think overall too).
They are not flawless but they are on play 90% of time since i have them... I hesitate to use the driver in a different build though: as they are relatively 'compact' ( bulk) and ok to me, and i definitely like bigger diameters... maybe put them in a closed box and add a pair of twelve for 250hz and lower, a la Seaton's sound Catalyst? Not sure if it would bring what i liked in the 12" and 15" i liked. Probably way better however: this kind of drivers begs for being used in three way with direct radiating driver of coax relief from bass duties imho ( and already said by other members). Few are ok for 2ways use imho.
I've had Cabasse goelette 500 ( with a two way cabasse coax from 1k and up, with tweeter, predecessor to the threeway they use now), System1200 and 800 in the last 4 years.
I liked them all but prefered the 1200 by wide margin. More directivity control and lower in freq and i prefer the sound of compression driver to tweeters.
My absolute ref is Tannoy DMT15mk2 used in wall ( for coax but i think overall too).
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Would it be an idea to differentiate the coax types? There are the PA type with visible traditional full size horn instead of dust cap, there are the short horn types hidden behind the dust cap, there are the hoof ones without horn but rather a dome and then automobile types. I assume we don’t talk about the automobile types. But what are the difference in performance of say a shared magnet with compression driver in a short horn compared to dual magnet (longer throat) and whether or not it’s neodymium. A table of application would help. Tannoy usually have the shared magnet type. But my DC6 have double magnets making the throat longer. Still no dust cap nor a horn extending the LF cone. My point is there are lots of variants which may be useable in different situations. Screw on HFs like Eminence is very practical but a 1” CD will definitely have its limitation in a short horn hidden behind the dust cap. And you pay for more magnet which wouldn’t be necessary and maybe even the magnets interfere? Voice coil z-axis alignment is probably a topic too. Are Seas and KEF types more aligned than the PA types? And what about voice coil size. So many options so little time.
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I haven't heard the passive ones yet. The active ones were not great but good - but they've got one flaw: The loudness and tweeter level pots are on the front in the middle of the PORT on a flimsy plastic part! Or in other words, where the vibrations the are the strongest! How stupid can they be? You can wait till the pots become noisy. 🙄
That's a very good idea but I would do that completely active. I've heard the difference on another a/p Tannoy but I forgot the model. The ammount of details, which were present on the active ones and were swallowed in the passive crossover, was staggering.