Sean, one thought has been bugging me. As you quite rightly say, dipoles, by the very nature of their design, must distort the sound. I bet, that most concert going Maggie, Sound-Lab or Quad owners will heartily disagree with that statement. I also, trying as hard as I might, don't hear any distortion. Perhaps the secret lies in the way I hear the differences, as described by me above, which I hold to be generic by the way, between the sound of the newer hornspeakers and dipoles. I do indeed find the sound of the A-Capellas "purer" than what my system AND the live experience can render. So what is happening here? Is it the dipole setup in the room, which will render the "theoretical" point of their distorting practically mute/moot, if its succesfull, is the ear so easily fooled, or is it just the fact, that dipoles distorting as they do, render a sound, that more often than not fascinate music lovers?
Wonder what your thoughts are.... Cheers, Detlof |
Sean. The newform ribbons go down to only about 1000 althought in my dr-8-2's I read the crossover was about 900 to two peerless 8" drivers. The back of the heavy ribbons are monopolar. The ribbons have a very small acoustic profile from 1khz up. The ribbon is 3-1/4" wide by 2-1/2" deep. It is heavily bevelled at the front of the structure. The newform ribbons is a very interesting design. A friend of mine who likes my newforms very much owns original quads driven by audio inovations..... |
sean: the only speakers i've ever heard that produce a believable 360º dispersion pattern are the radiostrahler mbl 101d's. the first few times i heard them at dealers and ces rooms, i couldn't imagine anyone's wanting them, much less at the price demanded. i've heard them now, properly setup in a home listening environment. they're driven by a pair of accuphase a 50v's (they really NEED the power) from a boulder 2010 pre, a burmester dac and transport and all connected with tara, the zero ic's and tara, the one cables. they do sound fabulous. ( and why shouldn't they with >$110k in electronics and wire?) but, truth be told, i still prefer my 3-way boxes; i can, literally, walk from my sweet spot to a position behind the speakers and perceive at every point a holographic image. what's more, my speakers also pass another critical test, IMO. when heard from another room, they sound like they're producing a live, albeit amplified, performance. -cfb |
Sean, you are dead right of course. It was the good old Quad 57, which had the backwave at least partially blotted out by a fairly thick felt layer and this speaker, especially in the HQD version threw an incredibly good soundstage. Many people preferred the 57 to the later iterations for just that very reason. Unfortunatedly the thing never played really loud and you had to sit exactly in the sweat spot to get the highs right. I've experimented with blotting out the back wave, but very dilletantly and unsuccessfully. I find the idea you bring up fascinating, but I'm not knowledgeable enough in these things to design or even dream of something similar. Besides, with my setup, it would be impossible anyway. |
Detlof, the thing with live acoustic instruments is that all of the sound is initially reproduced in phase and then is "distorted" or "delayed" by room acoustics & reflections. A single full range driver that radiates omnidirectionally in phase follows the same basic principles of the instrument it is trying to reproduce AND falls prey to the same culprit i.e. "room reflections" in like manner. In direct comparison, a dipolar driver is already distorted in comparison since it is contributing out of phase output at the same time it is in phase. It only gets worse from there in terms of the even greater problems associated with room reflections, etc...
I wonder what a panel type speaker sounds like with the back wave effectively nulled ? I've heard of guys building carefully thought out "enclosures" onto the back of them and being VERY happy with the results. This would give you the excellent transient response associated with these designs, get rid of the out of phase contribution that the back wave produces, increase low frequency output due to the lack of cancellation, should make placement a little easier, etc...
My thoughts are that a relatively deep "D" shaped cabinet with a curvature at the top and bottom would work best for something like this. That type of a design would not have any corners to produce standing waves nor have any parralel surfaces to aid internal reflections. An open "pocket" directly behind the panel would act as air spring tensioning, maintaining the panels linearity. The walls of the cabinet would be lined with a thick layer of insulation for internal absorption purposes.
I know that Newform markets ribbons something like this ( not sure EXACTLY how they are built ), so that may be something to look into. I don't think that any of them offer enough surface area to do low frequencies though, so it somewhat defeats the purpose of what i had in mind. Then again, we would end up with a front firing design that would probably lack the dimensionality, space and air that multi-directional designs seem to offer. Oh well.... Sean
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I agree with everyone that has mentioned Spica speakers. But nobody has mentioned the best Spica speaker. The designer himself said he liked the TC-60's the best. I have to agree with him. These speakers in a large room throw an unbelievably large soundstage. |
What Sean has heard with the AvantGardes, I've heard with the A-Capellas, which are also modern horn loaded speakers. I see his point about dipoles, radiating out of phase towards the back wall. However, when you listen to live music in a room or hall, you never just have sound reaching your ears in phase, having all sorts of reflections from everywhere in the listening area. This is probably one of the reasons, why a well set up pair of dipoles in a carefully treated listening room can sound uncanningly real, more real in fact, than the A-capellas, which though beautifully holographic, will sound just a tad too "pure", ethereal, speak artificial, compared to say Sound Labs or Quads. Though more holographic, they cannot really sound "dirty" like live music and dipoles often do. |
Spica Angelus are imaging champs and pretty easy to set up, just don't get carried away with the gain knob on your preamp (I blew the woofers on my Angelus'during a party). Celestion 700's did a credible job as well, but in general I found "box" style speakers just aren't up to the task. In my experience the most holographic speakers are planars; I've owned Apogee Duettas followed by Martin Logan Quests and Aerius (the Quests are in my main system, the Aerius in my home office system) have been wonderful transducers. Planars are the way to go, but, be ready to invest a LOT of time moving them around in the room til you get the placement just right. Once you set up planars properly you'll never be able to go back to sealed box speakers for critical listening again. I've always used pretty good electronics so I really haven't noticed associated gear making a huge difference with planars (I'm referring to imaging only, of course any change in gear will be heard). Your choice of speaker wire will make the biggest difference with planars, experimentation is necessary. YMMV |
Sugarbrie's right about the room and electronics playing a big part. If those are right, the best I've heard at disappearing are the Pipedreams, the Avalons, the Audio Physics, the mbl 101s and my speakers (Sforzando JL-1s, not currently marketed). With the Pipes and the latter two, you can sit well off axis and "see" the performers as though you were off to the side at a concert, or even walk between and behind the speakers right into the soundstage. |
And I agree the electronics matter also. (What happened to the edit function Agon??) |
I would concentrate on speaker placement and room accoustics more than the brand of speaker. |
No one here mentions the Spica Angelus or TC-50? These are an inexpensive way to get some good imaging (only if electronics are good). |
The first time I heard the 3-D thing was during a demo at a highend stereo place. Speakers were Martin Logan Aerius`s with Golden Tube electronics. I can`t remember what the cd player was. I could walk amongst the performers. kinda freaky. Total cost was about $4000. Dan R |
Point taken, Sean....I've heard the tannoy churchills disappear, which, considering their bulk, is impressive. Also heard the original snell J's running on the SF control amp with a little rotel 855cd....the rear basement wall just disappeared and music had depth out to the sidewalk and back.....it was scary....also heard my newforms with Single ended triode preamp[remember the N.E.W.?] and a group of us who were listening alll thought it was a religious experience. It was all music, the speakers simply were not there....it is more than just the speakers from what I've heard....But I've also heard little nears, the 10's disappear....in fact, my niece bought mine..... |
While i'm not knocking ANY specific speaker brand or type, i've seen a lot of "love" towards the Soundlabs ( probably deservedly so, but i don't know ). How can a speaker that radiates sound in phase on one side and out of phase on the other side produce as coherent of sound as a speaker that is phase coherent for 360* i.e. the sound coming out of the front, sides, rear of the driver emanates from the same source travelling at the same speed and in the same polarity ?
If you look at many acoustic based instruments, they radiate direct sound in phase in multiple directions i.e. a plucked, strummed or bowed string produces sound evenly around its' circumference and the entire length. I would "think" that a driver that had a similar radiation pattern would most closely appr what you would hear at a live performance. Maybe, maybe not. That's what i'm trying to find out here.
This is NOT meant to knock anybody or anything, it is a legit question. I am trying to compare different technologies / designs with how we percieve sound and music. I am interested in comments both speculative and based on factual knowledge of acoustics. Let's see if we can find out WHY different models / designs perform "better" than others... Sean
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no speaker will give you a better 3d sound than sound labs and tubes. if you have ever heard them you will see. |
Many speakers can do it but most electronics can't. I do agree with the recomendations on careful set up! Speakers are dumb, they just play what you feed to them, if you feed them a 2d signal you will get 2d sound. Feed them with electronics that can give you the magic and you get magic coming out! |
The spatial imaging is much more dependent on speaker placement within your listening room. Distance from the rear and side walls as well as toe-in all have a very large effect on the image generation. |
I have just this week recieved my new Audio Physic Virgo III's which are astounding and the best I have heard at reproducing all of your descriptions of 3D space and solid imaging, much improved over the previous model. |
I have heard a number of speakers do this very well. The Piega's, Avalon's, Kharma's and Rockport's are a few that do an incredible job at 3-D imagry. |
You will hear this with Avalon Eidolon speakers, with the right electronics and front-end. |
Well most feel it doesn't get any better then soundlab with tubes for the "disappearing act", though they take up more room then most can afford to lose. Also Avalon Acoustics, are known for there disappearing, this has been covered mainy times before and always the same answers, so there be a few more but they slip my mind(what's left any way) at the moment. I own avalons and love the "jumping" around they do, its pretty weird, in particular after you have a few into ya, nudge-nudge if you know what I mean :)
Tim |
While horns have never been known for "imaging", i was quite amazed at how solidly images were anchored when listening to a pair of Avant-Garde's. The "mid-sized" Pipe Dreams also had excellent imagery. Both of these were very stable and pinpoint. Keep in mind that a LOT of this has to do with the rest of the system though and not just the speakers.
As to being "immersed in sound", i have never heard anything that can present as deep of a soundstage as a point source full range driver with 360* of horizontal radiation. Sean
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