We begin at the beginning, with a quest for solace in a helter
When we get to the bass and upper bass and the midrange that's where extra brain size is required. The problem is to find and integrate a larger single driver with the speed and high frequency extension to seamlessly match an ultra-fast ribbon tweeter. The Celesta uses an asymmetric crossover scheme that has two different slopes for the tweeter and mid-woofer. Still success or failure hinges largely on that Celesta 6 inch driver, it most certainly has to be exceptional. This is how the manufacturer describes this driver. "A Six inch woofer with a 3" Hexatech aluminum 3.1 inch diameter long throw voice coil. The motor/ voice coil uses a hybrid Neodymium Ferrite magnet with a Titanium coil bobbin and a copper sleeve Neolin motor housed in a Uniflow aluminum diecast chassis". Understand all this innovative engineering cannot have any effect unless you find a way to eliminate enclosure resonances that would interact and smear the 6" woofer and the tweeters frequency response. The manufacturer's literature states that they have a proprietary Alta XTL (Extended Transmission Line) bass and cabinet tuning method.
Many years ago I attended a CES press demonstration using four Bang Olufsen Beolab speakers. All were using a DSP driven adaptive bass linearization system. It was intended to be a system using four speakers in a surround Audio Video home theater setup. That's valid if you never change your speaker's positions. And that would be the case if the movie and the screen was your priority. Like Carl Marchisotto intimated, designers do not design speakers that have ruler flat frequency response. If they did succeed most speakers might sound alike. I believe audio speaker design is in large part an art-form. In the real world the room is always there. So far no practical system has always totally and completely found the room's environmental/detrimental cure all. Unless you drag your Hi-Fi outdoors it is always a game of do whatever you can. To make a point, did you ever turn down the bass level and notice that the speaker sounded far brighter? The point I am trying to make is that everything affects everything else. Far better to listen in an environment that you know intimately and you will discover the speaker designer's voice.
A Forgotten Phenomena
Damn it, I had forgotten about this. My long gone unreliable but much loved Quad ESL 63 Electrostatic speakers (I nicknamed Sparky) had that ability. They were bipolar, meaning the sound radiated from the front and the back but very little energy radiated from the sides. Ergo, because of this phenomenon much of the junk within my room was taken out of the equation. However I would never have expected this transmission line speaker to do a similar disappearing act. The key is about the Celesta FRM-2 enclosure and that multilayer Damphard stuff. Then add the (If I told you then I would have to kill you) Alta XTLbass and enclosure muti-frequency tuning method. Also we should not discount the fact that the center of the mid-bass driver is raised about 34 inches above the floor.
The Proof Is In The Putting
That quality is contained on a recording of Harmon Lewis and Gary Carr's performance of Adagio d' Albinoni. This is a recording of a large Pipe Organ and a Bass Fiddle duet played in a large stone walled cathedral. There are passages containing very deep sustained bass organ peddle notes that echo off the walls. The organs reverberation reinforces the texture of the wooden reverberating sound of Carr's bass. His bow intones mournful feelings of pain and despair with a low moaning sound. At this point only a stone cold heart can ignore that deep quavering cry. This organic sound contains myriad sonic subtle overtones that if omitted would render it all mechanical and emotionless.
The Alta-Audio FRM-2 speakers speak with a remarkably defined voice. I would be remiss if I do not mention that Ribbon tweeter and the very clear stage it can paint. The match between these two drivers determines success or failure. The difficult crossover between the drivers is virtually undetectable. The tweeter has power articulation and speed that can complement and balance all the bass energy. As a matter of fact if anything it can generate to much energy. On some CD's I preferred to listen with the grill cloth in place. What better way to explain it than take a fun retrospective ride with the Beach Boys. The CD, Good Vibrations [Capitol CDP 0777 81299 29] is the previously unreleased, 30 years story of the Beach Boys Sessions. This disk contains original demos, radio broadcasts, separate vocal tracks and back up instrumental tracks and many live concert recordings. The very last cut is Surfer Girl, Live in Hawaii 1967. The sound quality is all over the place and that is a good thing. In the studio the raw mike feed sans reverb allows me to separate every voice and back up instrument as I sing along pretending to be one of the Beach Boys.
Remember, enjoy the music and from me, Semper Hi-Fi.
Review System Components
Ron is right, speaker design is an art, an art which is grounded in engineering. The Celesta FRM-2s are the first in a line of speakers from Alta Audio that were created using features developed through a design study that included feedback from reviewers, musicians, audiophiles, industry friends, other designers, and even a conductor. We took the time to listen at every one of the various stages, and some of the listeners even became beta testers. In order to keep ourselves grounded, we would try as frequently as possible to listen to live performances of natural instruments (not like we did not enjoy it). Occasionally we would even get a recording of a performance we had attended, we would listen, and I would get feedback from the beta testers. It all went to help tune the sound of the speaker.
In the case of the Celestas, they are called the FRM-2s for "Full Range Monitor". The concept being that in many listening rooms floor standing speakers get in their own way, as evidenced by the problems Ron has with floor standers in his room. A monitor speaker intrudes less and interferes less. Also, It will not act as a reinforcement point for standing wave resonances.
There is a problem, though. Most monitors cannot produce the bottom octave of sound that is between 30 Hz and 60 Hz. It is an octave that can be both heard and felt, and I feel is essential to reproducing most music. The trick is to reproduce that octave in a monitor speaker. The laws of physics get in the way. They say that size (cabinet volume) controls bass output. But the laws of physics are more complex. They also say that there are other methods to tune a speaker. One method is called the transmission line. It tunes a speaker through a tuned resonant column of air, much like a pipe organ. We developed a new transmission line tuning concept in the FRM-1, our prototype, and refined it in the Celesta FRM-2. We call that concept Alta XTL bass. The result in the Celesta FRM-2 is clean tight bottom octave bass with incredible amounts of output from a monitor speaker with a 6 inch driver. That driver, as detailed in the review, is of exceptional quality.
In order to control the bass energy from this system it is housed in a cabinet where all of the sides are made of our multilayered DampHard compound material which is non resonant and presents a hard surface to the drivers that does not flex. Extremely dense, it is much of the reason these monitors weigh 55 lbs. each. Its inert nature and the cabinet's shape help it sonically disappear.
This all results in a deep black noise free sonic background on which smooth acoustic images stand clearly. In to this system we ear tune the finest crossover parts to meld the woofer's output with the high frequencies from our ribbon tweeter. The magnetic material used in this tweeter is so powerful that we ship the speakers with tweeter covers to protect them from pulling in stray metal. Smooth and dynamic it melds seamlessly with the woofer with response that extends well beyond human hearing.