Jonathan wrote:Seriously, though, how was the sound quality (imaging aside)? I've heard the Bolzano Villetri's are "unique" (and I don't think they meant that in a good way) as far as sound goes, but of course the imaging allows you to experience them from more than one position. Depends on what you're going for, though.
I couldn't fault them for tonality or transient response.
I'd expect if you had a waterfall plot of their drivers, the'd be "best in breed" in those terms as well.
It's not just the spacial placement - it was the complete realism.
You know how it is when you audition a system...
You put yourself in front of it, and close your eyes, and see if "like that", you are convinced there is a real band in front of you?
With these, as I was sitting there, eyes open, I was convinced there was a band there - my eyes didn't believe my ears. The depth penetrated the wall (the speakers were only a few inches off the wall), and the band spread across between the speakers and beyond.
It was realistic enough - and of high enough quality - that you were receiving more convincing realistic data through your ears than you were through your eyes.
First time I've heard something THAT convincing - and as a CES Alexia Park veteran of many years - that's saying something, if I do say so myself.
that was why I bought my ML Odysseys.
and actually why I boought my KEF Reference 104/2 mains, too.
with the ML panels, I listened to a jazz CD and I couldn't literally tell if I was actually in a jazz club or a listening room at the store. I could pinpoint each musician, and which way he was facing in the recording. That's not mentioning the outstanding low end response those mains have. I could feel the drums right through the floor and leather sofa I was sitting on. Quite moving.
Not to bad for $6,500/pair retail. They handle a large room effortlessly as well.
That said, I'd like to hear the ones you linked if I get the chance.
I feel that level of realism is more important than being nit-picky about things like tonality, transient response, and stupid magazine verbage like Pace, Rhythm, and Timing. Obviously if they are that convincing they're doing something right. Just curious about them SQ wise, I was looking around for info on them and stereophile (I think) did a run-over on CES.
Ok so, basically how a speaker works is:
The voice coil is suspended in the gap of a magnet. When we send electricity to the voice coil from the amp, it is magnetized, and depending on the polarity (+ or - side of the sine wave) and amplitude (height of sine wave) of the wave, the voice coil goes in and out. It goes in and out because the magnetic field which is generated makes the voice coil attract or repel from the magnet.
Is all of that correct? Is the attraction/repulsion of a magnet to another magnet called polarity? Also, does anyone have any information on basic magnetism so I can get a stronger grip on how that works?
solacedagony wrote:Ok so, basically how a speaker works is:
The voice coil is suspended in the gap of a magnet. When we send electricity to the voice coil from the amp, it is magnetized, and depending on the polarity (+ or - side of the sine wave) and amplitude (height of sine wave) of the wave, the voice coil goes in and out. It goes in and out because the magnetic field which is generated makes the voice coil attract or repel from the magnet.
Is all of that correct?
Yup. Current flow in a conductor produces a magnetic field around the conductor. When the current is increasing, decreasing, or changing direction, the magnetic field changes. The magnetic field expands, contracts, or changes direction in response to the changes in current flow. In relation to a speaker, this is what creates motion with the voice coil.
solacedagony wrote:Is the attraction/repulsion of a magnet to another magnet called polarity?
Typically it's called polar orientation.
solacedagony wrote:Also, does anyone have any information on basic magnetism so I can get a stronger grip on how that works?
The magnetic circuit itself though is key - don't downplay having an actual understanding of how it works!
Essentially, for most speakers, you have ceramic/ferrite ring magnets - and just like any magnet, they have a north pole and a south pole.
With speakers, it's not critical which pole is "north" and which is "south" specifically - but let's abitrarily call the plane touching the top plate "north", and the plane touching the back plate "south"
A circuit is actually created - as soon as you attach the top plate to the magnet, it becomes charged with "north pole" magnetic energy.
And as soon as you touch the back plate (or more accurately, the entire T-yoke assembly with the pole piece included), it becomes charged with "south pole" magnetic energy.
If you follow the circuit (let's head south), magnetic energy flows out of the south pole side of the magnet, permeating the ferrous metal of the back plate, permeating the ferrous metal of the pole piece, all the way up to the top, where the pole piece passes through the hole at the center of the donut-shaped top plate.
The magnetic energy jumps "the gap" into the top plate, where the circuit is completed back at the north pole of the ring magnet.
That's how a magnetic field is created at "the gap" - it's not just that there's a magnet there... essentially, the entire pole piece is charged "magnetically south", and the top plate charged "magnetically north" - which sets up a field jumping the gap.
There are some critical considerations here, as well:
Stacking magnets doesn't really impact flux significantly, even though your motor can look monsterous... adding another ring adds only about 10% to the flux of the motor.
On the other hand, increasing the diameter of the magnets and motor can increase flux substantially...
...a wide-diameter single ring magnet compared to a quadruple-stack of a medium size magnet - there's more flux available with the wide magnet.
With the magnetic circuit, there are potential weak spots, as well.
The biggest is typically the joint where the back plate and pole piece meet - it's a high stress area, pretty tight, usually not as much metal there - and you can choke off your available flux (and therefore BL - or 'motor strength').
Another factor is the top plate - how tall is it? You can focus magnetic energy tightly into one powerful, but narrow top plate (making for a sub with potentially not much excursion capability, but a lot of motor strength), but you do risk choking it off if you get too tight...
...or you can spread it out across a taller top plate, establishing a very wide gap - maybe you are doing an underhung driver, with a very short coil but a very tall top plate - the inverse of an overhung driver, which uses a shorter top plate and very long coil.
Excursion, or Xmax, is traditionally measured (using "old school" style here) as the distance the voice coil can travel from it's centered 'at rest' position, to where the coil count in the gap (how many windings are in the gap at any moment in time?) starts to decrease - coils start leaving the gap.
Or, with an underhung driver, it's the point where the edge of the small voice coil reaches one edge of the top plate. Xmax is traditionally represented in this one-way motion manner of describing it - obviously a 2-way, or "peak to peak Xmax" would give you a number twice as large.
BL - that's a good measurement of potential motor strength...
"B" represents the magnetic field strength "in the gap", which we tweaked to our desired goal by manipulating magnet, top plate, and our elbow at the pole piece / back plate joint.
"L" represents the length of the windings that are suspended in the gap at any given moment in time. Note that given a particular magnetic field, you could either create a voice coil winding that was very very long (giving you high Xmax, but low BL - a high excursion sealed box sub), or you could create a voice coil winding that was very short (with more windings "in the gap" at any given time, reducing Xmax, but increasing BL - a traditional vented box sub).
Hopefully that helps a bit more, with respect to magnetics at work in the speaker!
Do you have a picture or any visuals of the circuit?
Everything from my post on is what I've actually learned or figured out myself, just tonight, to put this into perspective.
edit: I wasn't downplaying it, I just don't quite understand it yet :)
Your post helped a lot though.
Another weird thing I was thinkign about was:
To play at 50hz, the speaker needs to be going in and out 50 times a second. Now, speakers play ranges of frequencies, can't they only be doing one thing at a time? The speaker can physically only move one speed at a time, correct?
Also, "the gap". Are you referring to the hole in the middle of the magnet, the space between the south and north poles of the magnet? (bottom plate and top plate holding the magnet on, top plate being the one closest to the voice coil)
