Truely 3D imaging is pretty hard thing to arrange. There is one local DIY builder and album producer here that has multichannel system of his own. It uses eight speakers, one in each room corner. And with carefully designed method of producing recording it can envelop very realistic soundstaging. But that's very limited. Just to few hundred albums he has personally made, nothing else really works.
Commercially there is no future for such system. There is a big headache placing those 5.1 speakers in most rooms along with rest of the decoration and that's also just a compromisse. It doesn't allow that much real height information through. There was few albums in early history of SACD that used .1 channel for ceiling speaker but like you can imagine it isn't usable with other albums.
Using carefully placed speakers with well implemented ambience speakers it's possible to have pretty realistic results. This solution also reduces the sweetspot effect so the soundfield is much more usable all around the room. Just like in a live event. But only with properly made acoustic material. Studiostuff is still studiostuff.
Jussi
Commercially there is no future for such system. There is a big headache placing those 5.1 speakers in most rooms along with rest of the decoration and that's also just a compromisse. It doesn't allow that much real height information through. There was few albums in early history of SACD that used .1 channel for ceiling speaker but like you can imagine it isn't usable with other albums.
Using carefully placed speakers with well implemented ambience speakers it's possible to have pretty realistic results. This solution also reduces the sweetspot effect so the soundfield is much more usable all around the room. Just like in a live event. But only with properly made acoustic material. Studiostuff is still studiostuff.
Jussi
I've read the thread with great interes, but it seems I was not very focused because I didn't notice any reference to orion++, that's why the post...
Well, although I don't have the knowledge to properly understand the exact behaviour of a rear tweeter, and especialy the psyhoacustic implications, I guess there must be reason why full dipole sistems are having a good imaging... Maybe properly implemented it should be taken into consideration...
The examples are fullrange drivers in OB, which are having good results, open back ribbons, omni speakers like pluto (although pluto is not exactly a dipole to the upper octaves...) or visaton's fontana..
Well, although I don't have the knowledge to properly understand the exact behaviour of a rear tweeter, and especialy the psyhoacustic implications, I guess there must be reason why full dipole sistems are having a good imaging... Maybe properly implemented it should be taken into consideration...
The examples are fullrange drivers in OB, which are having good results, open back ribbons, omni speakers like pluto (although pluto is not exactly a dipole to the upper octaves...) or visaton's fontana..
Well. It seems like my Esotars aren't coming back. Some of the failure was fixed but not all of it. Still 2-3dB tolerance between individuals. Personally I think that's too much for such top of the line drivers. Therefore I'm very seriously considering H1214 or similar 27mm Seas aluminiums in this system. No chamber so I could try that rear tweeter with sane effort. Waveguides to both directions.
What do you think of the bass solution?
Monopoles, single or in stereo, along sidewalls, close to mains or flanking listeningspot, single sub along frontwall..
Dipoles. Well the crankshaft which is still pretty bulky and large for this room. And it still is pretty much as small as it gets as a 4 driver W-baffle. Straight 4x12" SLS panel is also possible. A bit like the mains, just another similar size panel along the mains. But that looks like a wall then and I don't know how close I can put them without sacrificing main speakers performance.
New, fresh and crazy ideas are welcome. I think 2x10" 25W pack can play down to 80Hz or so without compromisse. Deeper by compromising SPL and dynamics. But I wouldn't want to go there since there is plenty of high efficient potential on the top.
Jussi
What do you think of the bass solution?
Monopoles, single or in stereo, along sidewalls, close to mains or flanking listeningspot, single sub along frontwall..
Dipoles. Well the crankshaft which is still pretty bulky and large for this room. And it still is pretty much as small as it gets as a 4 driver W-baffle. Straight 4x12" SLS panel is also possible. A bit like the mains, just another similar size panel along the mains. But that looks like a wall then and I don't know how close I can put them without sacrificing main speakers performance.
New, fresh and crazy ideas are welcome. I think 2x10" 25W pack can play down to 80Hz or so without compromisse. Deeper by compromising SPL and dynamics. But I wouldn't want to go there since there is plenty of high efficient potential on the top.
Jussi
I like U-baffles up near the front wall. Right now I'm using an Adire 18" Maelstrom in a 23" deep U. With stuffing that gives me an Fequal of 50hz. I pick up some of the room gain of monopole, yet retain much of the sonic room benefits of dipole, making it a nice hybrid. I do believe that stereo is better for any open solution, because I have yet to find an open alignment single sub that doesn't collapse the soundstage down toward the sub no matter how low and/or steeply it is crossed. If you have an explanation let me know.
If your listening position is far enough and room narrow enough, corner dipoles or U's are an interesting prospect to eliminate the floorspace issue.
If your listening position is far enough and room narrow enough, corner dipoles or U's are an interesting prospect to eliminate the floorspace issue.
johninCR said:
How large room do you have and how adequate 18" Maelstrom in 23" U-baffle is? I guess it needs some space behind it so U can really work?
This is definitely one solution to consider. Some Finnish builders have group ordered US made Sound Splinter Premium models, mostly the 15" model. I don't know how high quality units they are. At least they look darn good (http://www.soundsplinter.com/images/drivers/RLp15-top.jpg) and for what I know are made by TC Sounds...? But how high such woofer can play? Can 500-550mm U-baffle operate up to 80-100Hz for example? And how steep cross (with notch perhaps) does it require above that?
Pretty high mms so structure should be very heavy that it doesn't dance around. 806cm2 cone, +-24mm linear excursion. With 550mm (22") deep U-baffle is could create about 7dB more ouput than 4x12" SLS 550mm deep W-baffles in dipole. Or have pretty identical output against such dipoles in stereo.
I don't have that much space for stereosolution. Basically a compact structure along the mains (between main and sidewall) or listeningspot flanking structures are ok if stereo operation is needed. There is enough space along the frontwall to a medium size structure but there isn't that much space to move it so it should work pretty much where it can stand. And this also means mono operation.
Good question. At least it can be a psychological effect while you know the subwoofer is out there and it's turned on. I've heard some cardioid systems that have "no depth" in their imaging since frontwall is right behind them but the problem is solved by turning the lights off.
Positioning and integration are other, more real, issues. Adding subwoofer to a monopole main is propably more difficult than adding subwoofer to a dipole source. Monopoles playing overlap region just boost each other, add monopole source to dipole creates cardioid like radiation. This is also one aspect I could explore by adding the closed monopole subs along the mains.
One possibility is to use larger number of subs. Like this article suggests:
http://www.audiovideointeriors.com/images/archivesart/0106toolemultsubs.pdf
Perhaps four small closed subs? I can't get them to each walls centerline but for example but along the mains and sweetspot flanking position could be occupied at the same time. Use DCX for the bass (allows LFE input since there is 3 input channels) so flanking woofers can be delayed a bit and still be in phase with the others. But would this really create improvement over single stereosub configuration? Physically it's pretty much the same. Just four very compact cabinets, each driver in its own cabinet and four amp channels.
Jussi
Jussi: Can you point me towards any Finnish audio forum? You do seem to have a lot of interesting constructions over there! 🙂
Jonasz said:
I'am afraid I can't. They are all in finnish and really intresting constructions are pretty rare so they just come across time to time. Mostly people focus on DIY subwoofers with traditional drivers and solution as well as to speakerkits.
I understanded that you already know Kimmo Saunistos projects?
Edit: Here it is: http://kotisivu.dnainternet.net/anukaa/
Only if you promise not to flood his email on different requests since the pages are in finnish.
And Oh, my wife seems to be on the "single woofer along the frontwall by the equipmentrack" - side on this bass issue.
Jussi
Isn't a 1/2m pipe going to have a fundamental resonance at 170hz, so up to 100hz you should be fine? Mine is pretty big, but that was just to give you an example. Half the depth is only -6db, so just double up the drivers.
MBK said:LOL!!
I wasn't kidding. There is a natural conflict between human vision and hearing and in most cases human mind takes vision more seriously than what you hear. So the illusion of symphony orchestra playing in your livingroom doesn't work that well if the room is way too small. Naturally there are acoustic aspects too but even while acoustic problems are mostly solved human vision causes problems. Listen with your eyes closed ?
johninCR said:
1/2m isn't a problem. How does it sound, what kind of mains do you have, what kind of crossover do you use, is U alone as a sub or is there a stereopair for it?
Jussi
I wasn't doubting your story - on the contrary, I thought this may well solve a lot of acoustic problems ;-)
MBK said:
Well, I don't know about that. But like you propably know the less you trouble your mind with small things the more you can relax and enjoy most of the performance. This goes pretty well with audio equipment. I know I'm considering things way too complicated and thorough way, many things are propably irrelevant considering the "whole picture".
More knowledge, more pain. 😉
Jussi
Jussi,
I change my mains constantly, but I generally have at least one 15" per side for dipole bass augmentation. Right now I'm experimenting with dipole waveguides down to below 1khz in an attempt to achieve constant directivity. Then as the waveguides lose control, dipole polar response takes over. My goal is constant directivity and a balanced polar response across the spectrum. The initial WG baffles are proving to me that the idea works. (ie at the sides the sound is quite balanced, unlike every other OB I've heard where the mids have wide dispersion leading to an unbalanced response at the sides that must lead to an unbalanced in-room response).
If I had 2 Maelstroms, I'd build them into my mains. I've got a pot across one of the VC's right now, and at some point I'll try a comparison of that means of control to powering both VC's and control via amp and EQ. The SQ of the U is much better than the big EBS box it was in before, although stuffed ports brought the big box pretty close.
I change my mains constantly, but I generally have at least one 15" per side for dipole bass augmentation. Right now I'm experimenting with dipole waveguides down to below 1khz in an attempt to achieve constant directivity. Then as the waveguides lose control, dipole polar response takes over. My goal is constant directivity and a balanced polar response across the spectrum. The initial WG baffles are proving to me that the idea works. (ie at the sides the sound is quite balanced, unlike every other OB I've heard where the mids have wide dispersion leading to an unbalanced response at the sides that must lead to an unbalanced in-room response).
If I had 2 Maelstroms, I'd build them into my mains. I've got a pot across one of the VC's right now, and at some point I'll try a comparison of that means of control to powering both VC's and control via amp and EQ. The SQ of the U is much better than the big EBS box it was in before, although stuffed ports brought the big box pretty close.
Hello,
I like to try JohninCR's bass solution with the U frames but the Maelstrom's are too expensive. For less price I'd try stereo of the Dayton HIFI 15". (Multiple drivers if necessary) Displacement per dollar, however, the Maelstrom is still good.
One advantage of the Daytons is they can be crossed at a higher frequency because they have low distortion around 200 hz. In my design plans, I would benefit from that.
For really low bass I'd try a MLTL.
JohninCR, at large excursions, is air flow noise from the rear a problem? Does the stuffing help? What does 'WG' stand for as in 'WG baffles'? And, what tools did you use to design your U baffles?
When designing a U frame, you use stuffing to match the front radiation with the group delay of the rear? I'm not sure if I understand this right...
I like to try JohninCR's bass solution with the U frames but the Maelstrom's are too expensive. For less price I'd try stereo of the Dayton HIFI 15". (Multiple drivers if necessary) Displacement per dollar, however, the Maelstrom is still good.
One advantage of the Daytons is they can be crossed at a higher frequency because they have low distortion around 200 hz. In my design plans, I would benefit from that.
For really low bass I'd try a MLTL.
JohninCR, at large excursions, is air flow noise from the rear a problem? Does the stuffing help? What does 'WG' stand for as in 'WG baffles'? And, what tools did you use to design your U baffles?
When designing a U frame, you use stuffing to match the front radiation with the group delay of the rear? I'm not sure if I understand this right...
Hara said:
The Maelstrom is just one of the drivers I had, but didn't have room for the box, so I cut it in half. Stereo would be better if it wasn't for the f%&#ing theives who stole my other one, I'd have stereo.
Tools- Just a saw and glue. Seriously though, bass is about delaying the rear wave. Linkwitz gives us the formula for Fequal, which is the frequency where the rear wave is only 90deg out of phase from the front, so it neither cancels nor reinforces it. Below that point, dipole cancellation rolls it off at 6db/oct.
Fequal= (.17x343m/s)/D in meters. "D" is the added distance the rear wave must travel to your ears compared to the front wave. In my U-baffle, the rear radiation must travel to the rear edge, then back to the driver baffle plane before the remaining travel distance is equal to the front, so my "D" is greater than 1m, making my driver size box 23" deep the equivalent of a 4m wide flat baffle.
The open cavity behind the driver is essentially a TL and will have resonances that start at 1/4 wavelength of the TL length. You can't just operate below that frequency, because in these very low frequencies the air in the cavity moves as a lumped mass, making the opening at the back the rear wave source. As this behavior changes in higher frequency to sound travelling down the pipe is the cause of the fundamental 1/4 wave resonance. That's where the damping material comes into play. It prevents the lumped mass behavior and forces the pressure front to travel from the rear of the driver instead of instantly being at the terminus.
Without the damping you lose the rearward travel distance or a full octave, making an undamped U-baffle equal to a dipole of the same dimensions. It damps that fundamental resonance at the same time, making the sub useful to higher frequencies. JohnK has info about how to damp a U in his tech studies at www.MusicAndDesign.com , he refers to this lumped mass behavior as the resonance creating negative group delay. JohnK's site and Linkwitz's site have all the info you need for building open baffle alignments, although some of it takes reading a number of times to understand and they don't always boil things down to their simplest form like I tend to do.
I used WG for WaveGuide. No, I can't hear any driver operation noises.
JohninCR,
Thanks. The boiling down part is really what I need. I've looked at both sites and there is a lot of information. The hard part is trying to understand where to start.
Thanks. The boiling down part is really what I need. I've looked at both sites and there is a lot of information. The hard part is trying to understand where to start.
Hara,
Sorry, I have a typo that I can't fix. A half meter deep U is equal to a 2 meter wide flat baffle. For the flat it's a 1m delay for the rear wave to get around the side. For the U that meter is obtained by travelling rearward 1/2m first, then back to the front baffle.
Sorry, I have a typo that I can't fix. A half meter deep U is equal to a 2 meter wide flat baffle. For the flat it's a 1m delay for the rear wave to get around the side. For the U that meter is obtained by travelling rearward 1/2m first, then back to the front baffle.
Ok. So I switched the tweeter. Changing the damping material behind the dome helped but still tolerance between the Esotars is too much. At least for me. So Seas aluminium it is. H1214. Famous H1212 without the chamber. Leaves some space to experiment the rear tweeter if it seems necessary and intresting. Also need a couple of unmodified waveguides...
But the bass. That darn bass. I used Linkwitz spl_max spreadsheet to estimate few constructions. Since system has separated lowmidrange drivers cross could be a bit lower and gentler than in Orion, Phoenix or NaO. I thought something like 80-100Hz 2nd order if possible.
Original Beethoven, godfather of this system, has four 12" woofers in 550mm deep W-frame. And I assume it also uses four Madisound woofers that are also used in Phoenix woofersystem. But just two in Phoenix. So it's 530cm2 cones moving +-6mm linear. Beethoven system is recommended for pretty large rooms, 40m2+ or so. From displacement view two 12" XXLS woofers move pretty identical amount of air in same size W-baffle. This should be pretty adequate in my situation. Along sidewalls capacity increases another 6dB. Difference to standard Orion (2x352cm2, +-12,5mm) is 6dB, 12dB if placed along sidewall.
So it seems like a done deal. But there still are few aspects. First, two XXLS woofers basically can't be connected parallel. Minimum impedance drops to 3,3 ohms creating pretty demanding load for the amplifier. With four woofers configuration would be easy. Here the SLS option runs into play. Four 12" Peerless SLS woofers. Open frame, nice excursion, large cone, affordable price, nice curves. Nice 91dB+ efficiency for each. All together 97dB efficient (max, going down towards low bass), 6,5 ohm minimum load. Easy to drive with pretty much any poweramp. Runs out of excursion below 40Hz with modest <100W power, above that same power creates more SPL than listeners can handle. Also 4dB more linear excursion limited SPL or (while even the XXLS option is adequate) could deliver lower distorsion.
SLS downside is the size. It's less expensive, more efficient, easier load and more SPL capacity than the XXLS option. Pretty much all plusses there. Except the size. If I remember I introduced my "crankshaft" idea earlier in this thread. It is pretty large. Especially from the side if "D" is increased up to 550mm. From the front it's 340mm wide which is exact match for my panel width. At least the front perspective is the one I should use if I start to negotiate them into our livingroom. 😀
Thoughts, ideas ?
Jussi
But the bass. That darn bass. I used Linkwitz spl_max spreadsheet to estimate few constructions. Since system has separated lowmidrange drivers cross could be a bit lower and gentler than in Orion, Phoenix or NaO. I thought something like 80-100Hz 2nd order if possible.
Original Beethoven, godfather of this system, has four 12" woofers in 550mm deep W-frame. And I assume it also uses four Madisound woofers that are also used in Phoenix woofersystem. But just two in Phoenix. So it's 530cm2 cones moving +-6mm linear. Beethoven system is recommended for pretty large rooms, 40m2+ or so. From displacement view two 12" XXLS woofers move pretty identical amount of air in same size W-baffle. This should be pretty adequate in my situation. Along sidewalls capacity increases another 6dB. Difference to standard Orion (2x352cm2, +-12,5mm) is 6dB, 12dB if placed along sidewall.
So it seems like a done deal. But there still are few aspects. First, two XXLS woofers basically can't be connected parallel. Minimum impedance drops to 3,3 ohms creating pretty demanding load for the amplifier. With four woofers configuration would be easy. Here the SLS option runs into play. Four 12" Peerless SLS woofers. Open frame, nice excursion, large cone, affordable price, nice curves. Nice 91dB+ efficiency for each. All together 97dB efficient (max, going down towards low bass), 6,5 ohm minimum load. Easy to drive with pretty much any poweramp. Runs out of excursion below 40Hz with modest <100W power, above that same power creates more SPL than listeners can handle. Also 4dB more linear excursion limited SPL or (while even the XXLS option is adequate) could deliver lower distorsion.
SLS downside is the size. It's less expensive, more efficient, easier load and more SPL capacity than the XXLS option. Pretty much all plusses there. Except the size. If I remember I introduced my "crankshaft" idea earlier in this thread. It is pretty large. Especially from the side if "D" is increased up to 550mm. From the front it's 340mm wide which is exact match for my panel width. At least the front perspective is the one I should use if I start to negotiate them into our livingroom. 😀
Thoughts, ideas ?
Jussi
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