Stereo Loudspeaker System
IDS-25 Reviews
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6/22/06 by M. P.
Your IDS-25 speaker design is extremely impressive. I'm no engineer – my background is mathematics, with a BA from Reed College in 1980. The term that comes to my mind is "elegant". I haven't had such an impression of elegance about a loudspeaker design since I first read about the old Ohm "F" system. You seem to have solved at a stroke most of the problems that plague loudspeaker designers. The only aspect of the description that took me any time to accept was the part about the 25 drivers, each with an effective cone area of 5.7 square inches, being equivalent to the cone area of a single 16-inch woofer. "If the effective area is the same, what is the advantage of using 25 drivers?" I wondered, until I remembered that each of the 25 small drivers has a voice coil of its own. This brought to mind the concept of "sectional density" and made it quite clear to me that the control of the amplifier over the motion of the 25 small cones would be far superior to the control possible over the much larger 16 inch woofer cone.
Your discussion of Doppler distortion was interesting. Most other speaker
designers seem to gloss over this problem, if not ignore it entirely. Your
remarks on the advantages of eliminating crossover networks were also
enlightening, especially the part about the drivers interfering in the region
of the crossover frequency. Perhaps most refreshing of all -- my voodoo
detector didn't trip even once while reading about your IDS-25. Your claims for the system appear to be firmly grounded in
reality. This makes me wonder how the self-styled "golden ears" of
the industry have reacted to your product. Badly, I fear -- or with the smug
silence of willful ignorance. All told, a very impressive achievement. I can
only sigh wistfully and wish that I could afford a pair!. Sadly, I'll have to
continue to make do with the vintage bi-amplified ADS L1530 loudspeakers in my
main system, and the Thiel SCS monitors in my smaller system -- at
least until I win the lottery :-)
3/8/06 by B. F.
I had the pleasure to hear the speakers you designed at Ken's this past weekend. Having seen pictures that Ken e-mailed me before I stopped over for a listen, I was surprised at how much smaller they really were. Not the height but the small footprint and very small drivers.
I was shocked at the extension, power and weight of the low frequencies. Also pitch, dynamics, tonal balance and transients were superb. The fact that they're meant to be positioned against the wall makes them even more appealing for small rooms where it's often difficult to move speakers out into the room. Even against the wall they produced good imaging and soundstage depth.
Anyway, I just wanted to say, great job and I very much enjoyed hearing your speakers.
2/3/06 by J. L.
What I heard
over my Roger Russell Vacation
I've been e-mailing this retired loudspeaker engineer for nearly 10 years. Of
course I can bring nothing to the table for this guy technically, but I sure
have fun reading his responses to my otherwise meaningless, never-ending
barrage of e-mails. It's almost as if he's a celebrity in my mind. He
sent me a response to an e-mail on 11/6/2003 (and, yes, I archive ALL e-mails!)
that went like this:
"I have created a new speaker system but am not ready to give out details
yet. It's sort of radical but for me that's not unusual."
I never questioned him about this new "radical" design because I
never thought that his former masterpiece, the XR290, could be outdone. Did I
say "former" masterpiece? So, this guy has been sorta like
Willy Wonka to me since I can remember first talking to him back in 1992. I
then wondered "What's going on with this candyman?" Without all the
"magic" tools available for R&D purposes, what kind of speaker
system built at home could possibly give a thoroughly researched-and-designed
system any run for the money? What could be any more radical than a triple-column
(woofer, mid, tweeter) speaker system? And what could this "radical"
design even look like? It's beyond me. He's gotta be nuts....that's all
there is to it.
Almost two years go by after reading about this new design. Must not have been
so radical after all. What now? As it turns out, Mr. Wonka publishes the recipe
to his new candy in an audio magazine in November 2005 for everybody to make
for themselves. But, wait a minute! The recipe has some of the key
ingredients...but obviously lacks what most people would call the bass mixture.
(get it?...bass mixture!) These speakers become known as the IDS-20 loudspeaker system and I build a pair for myself. Next comes
the imaging....depth.....and spaciousness.
Before the IDS-20 (the BEST $200/pair speakers I've
heard, by the way), I really didn't know much about imaging, depth, or
spaciousness. And I still don't claim to know much about it. I had heard the
terms, but never really heard the qualities. Or had I heard the qualities and
just not realized it? Hmm. Some of the best speakers I remember listening to,
as far as having open, effortless sound, would be a pair of Martin-Logan
electrostatics. Thinking back, I can remember the sound of a particular pair of
Martin-Logans as being very wide and open. It was almost as if the band was in
the same room. That kind of sound was very pleasing at the time, especially
since my uncle and I were always haunting the local home theater stores and
auditioning many speakers over a relatively short period of time. (averaging
4-5 stores on a given Saturday) But that experience was well over 5 years ago.
I'm sure my opinion today might be much different. I believe the term
"coherence" had something to do with the sound of the large
electrostatic panels. But even back then the sub-woofer bringing them
"up" in the low end left plenty to be desired. I've played with many
subs and their controls, only to be disappointed with their overall balance
with their respective speaker systems. And who knows what kind of tone-deaf
person set up the sub for demonstration purposes? It was most likely a person
who believes that more bass is, well, better. Needless to say, external
sub-woofers have never been a purchase I've ever considered spending my money
on; except with a set of computer speakers. The McIntosh ML-series (4's in
particular), have been the star of the show for me for a long time. So, it was
back to the good-ol' ML-4s with their beastly cabinets, and reasonably smooth
response.
Since everybody is fully aware that bass is a good quality to have in a pair of
loudspeakers, it's also fair to assume that most people assume that bass is
only re-creatable via a large woofer or a sub-woofer. I think it's also
fair to say that most people might think that a woofer less than, say, 6-inches
just can't put out any decent amount of bass. The pre-conceived notion!
When I built my IDS-20 speakers, I couldn't believe any
loudspeaker engineer would even think about a column of 20 four-inch full-range
drivers. But this is THE loudspeaker engineer! THE man! The guy
whose work I've worshipped since I was eight years old. I could fathom a good
mid-range and a decent high-end...but bass? It didn't take too long to figure
out "hey, these things are something else!" Getting to work
late, on average 15 minutes a day, has been due to the fact that these speakers
are like a drug....a really GOOD drug! Listening to music BEFORE going to work
was normally something I did IN the car. Not any more! This aural
"high" (and lows, for that matter) is continuously repeatable each
time I listen to these things. "How can it get much better than
this", I ask myself? Turns out the "pusher" knows what his
newfound addict has been in search of. And for something better to be created
was just a bonus. It turns out the "pusher" is an addict himself.
After a self-invitation to the 'burbs of Orlando, THE
man allows me to take a free dose of his new drug....IDS-25. (whoa...good stuff, man!) NOW the
speakers are getting SMALLER, but more PLENTIFUL. The laws of
fuzzy-physics are certainly being broken at this point. After about, oh,
10 seconds of listening to these things I realize that this is the best pair of
speakers I've ever heard....period! I MUST have some!!! I can
picture a graphical depiction of how a speaker's response curve might look as
related to how it sounds to me. Sometimes the curve is heavy in one or
two of the three qualities known most commonly as bass, mid-range, or
treble. The IDS-25s, in my mind, were the closest thing
to a ruler-flat line that I've ever heard. Perfect balance in every
respect. It's almost as if the speakers were connected directly, somehow,
to my eardrums. I can't really explain it. Did I say that I MUST have
some? And then there's the amazing sense of "being there". I've
heard speakers that can project a decent image BETWEEN two speakers, but not
OUTSIDE of the left and right extremities. The IDS-25s did just this; and are simply amazing at doing so. Then
comes the "surround" experience. I'm not talking 5.1 surround, I'm
talking PURE 2.0! This is what I assume is called
spaciousness. I've only experienced spaciousness like this through
headphones. And it wasn't as good through headphones as it was through
the IDS-25s. I MUST have some!
I think a more appropriate description of IDS-25 could
be (I)ntelligently (D)esigned (S)peakers.
I don't know if I can put many more words together to try explaining what I
heard through the IDS-25s because I just don't know the proper
terminology to use. I'm sure one of the main terms I'll be using in the
future, however, will be "Pay to the Order of......."
....and I get irritated at my child for always saying "I want...I want...I
want"
Since THE man left McIntosh back in '92, it's been TOO-BAD SO-SAD for them.
Oh well, you STILL THE MAN!
2/3/06 by J. L.
4/2/04 by R. A.
Holy smokes! Roger did as he promised. He knocked my socks off!
I am going to try to accurately describe the most incredible listening experience I have had in my many years of auditioning various high-end audio systems. I actually heard clean, clear, undistorted, and flat bass from an array of drivers each measuring slightly more than 3 inches in diameter. What really makes this speaker system amazing is that it exhibits so many strong positive attributes, it is difficult to find fault with the IDS-25. The sound I heard from these speakers made me feel just like a dog staring at a fan. Ever watch a dog try to figure out something puzzling? Be it a sound or object, he looks at the source of his amazement, turns his head one way then the other in an attempt to understand the issue that now has become the center of his attention. Yes, that was me, only it was my mind struggling to grasp the situation presented. One knows exactly what a small cone driver sounds like and to have such great sound come from an array of small drivers, it nearly completely messes with one’s head to the point to where one simply cannot accept the facts presented. What are the facts? One fact is that high-end sound is coming from small, near transistor radio sized speakers. It is as if suddenly everything you instinctively know and expect, now no longer applies. If you can imagine being suddenly placed in an environment that is so bizarre and twisted, that your eyes outright lie to you, then that would be yet another way to describe that day. To coin a phrase, it is “so wrong”. Yet in all that “wrongness” things sound so very, very right. I also felt very much like Alice. The Alice from the Looking Glass. The difference being that the end result was a very pleasurable experience and without all the nonsense. Could one call it a paradigm shift? No. Paradigm transformation might be a better term.
My Background
I am a former electronics technician with experience in consumer and broadcast electronics. I have since changed careers since those days, and within the past few years have resurrected that talent for electronics as well as my passion for music. Yes I am a music nut. I listen to music at least 50 hours per week. I consider myself very lucky to be able to listen that much as my current employer actually wants me to work from home. Why did I leave the electronics field? As a general rule, there are a lot more people who have computers than have radio and TV stations. It is a simple matter of supply and demand. I currently do Information Security and Protection for a large, well known financial institution. I currently own a pair of XRT22 speakers coupled with a McIntosh MC2500 amplifier. Other equipment I currently use is the McIntosh C22 preamp, MR67 tuner, MQ108 equalizer, and a MCD7008 CD player.
Imaging Impressions
For the first time in all my experiences with speakers, I heard precise, accurate, and well defined imaging completely free from the “miniature orchestra” effect. Electrostatics, while transparent, suffer from the mini-orchestra effect greatly. For those people who like and desire that experience, this speaker system is not for you. When I first played one of my favorite audition selections, “Schererezade”, 2nd movement, DG 415 512-2 (which is out of print by the way), I was immediately moved forward to near the conductors position relative to the orchestra. This I found to be an interesting effect. Other speakers that I have listened to placed me further back. The next thing I noticed was that the placement of the instruments was so accurate that I could easily detect that the recording was made using multiple microphones. The spatial characteristics of the various solo instruments as they played assured me of that. It may have been that 2-3 instruments had one microphone, but the impression of a multi-miked session was still rather profound. Each instrument was placed precisely “there and there and there” within the full sound stage with “there” defining the z axis precisely.
The sound stage was every bit as full as Roger’s other late designs with the distinct impression that the wall was gone and that the room has been magically transported to the floor of orchestra hall.
Pinpoint accuracy is generally not a desirable attribute for imaging as it is not very realistic. Precision to the millimeter is desirable and realistic however and is an accurate description in this case. I do have to admit that I heard the valving of the various wind instruments as never before. This particular DG recording is unique in that the opening and closing of instrument valves is audible. Some have said this recording was made with the microphones placed very close and I would have to agree. I like it as the sound of the valves adds an intimacy unlike any other recording that I have in my collection. In this case, the sound from the valves also confirmed the precise location of the instrument. If there were any issues with frequency and phase, there would be a slight shift in position between the valve sound and the instrument. There was none that I could tell and it was spot on.
Anne Sofie von Otter’s recording of Offenbach arias (DG 289 471 501-2) was transformed into a live performance. Track 7 of this CD features 5 singers in addition to Ms. Von Otter. At the time of this writing, UMG/DG has a video of the performance of Sextuour de l’Alphabet “S.A.D.E.” at rtsp://ra.universal-music-group.com/dgg/rv-4715012-otter-offenbach-promo-tr07sextuor-S.rm. In this delightful but short work, Gilles Racon stands next to Anne Sofie on the left with the remaining 4 singers on the right. What was surprising about the performance as heard through the IDS25s was that the four tenors on the right were distinctly placed on the stage with each in a different position, not that they were just placed on the right side. I could hear that Gilles Racon was standing to the left of Anne Sofie, not just that he was in the general vicinity. I tried to explain to those with me what I had just heard by saying, “The singers were there and there and there…” pointing to precise spots within the sound stage with my finger.
B&W makes a fine speaker system that images well, but the sweet spot is so small that it makes it rather impossible for more than one person to fully enjoy the imaging. This line array makes for a sweet area that is larger than even the McIntosh XRT22 line arrays.
Many times people describe point sources as something desirable, but the truth is that many instruments are anything but point sources. A piano is one such instrument and an electric guitar is another. Yet the imaging capability of a point source is something quite desirable. What Roger Russell has done is combine the best qualities of a vertical array with the best qualities of a point source in one package.
But how does it sound?
In short, it sounds superb. The bass is well extended in frequency response and quite deep. If anyone has heard a well designed 15 inch woofer, then that is the frequency response that one gets. The frequency response is such that great one keeps looking for the sub woofer, which, of course isn’t there. But your eyes and previous experiences still lie to you. It is difficult to relearn or adjust to something after years of life experience.
If you can imagine hearing a pair of 15” woofers that have almost no mass, that is what you get. The physics behind this is the law that states that a body in motion will continue to do so. The greater the mass, the more likely it is going to resist any change. With the reduced mass of individual drivers, reproducing a bass drum or kettle drum or any deep percussion instrument for that matter, is much more accurate and realistic.
I also listened to “La Boheme on Broadway”, Dreamworks SKG 450 408. I have listened to this recording many times, and what happened when listening to this recording through the IDS-25s startled me. I could now hear quite plainly when the performers faced the microphone and when they did not. I was greatly surprised by how much of a difference it made when listening through the IDS-25s.
Various instruments
The plucking of the strings of a double bass is quite startling when heard through the IDS-25s. The initial pluck is heard clearly and is not muffled.
On conventional systems, the harmonics of the large bass drum and timpani are missing. The sound that the drum makes when initially hit is sharp and distinctive. The IDS-25s reproduce the bass drum like no other speaker I have ever heard save for the XR290 with its four 12” woofers per side. Still, there is a unique quality to the bass that is so life-like and real that I doubt any other speaker system can reproduce it. Not even the XR290 can reproduce that sharpness of bass. I attribute the sharpness of bass to the physics behind using multiple small drivers.
Mids are smooth and the highs are crisp and accurate. The upper end is so darn clear that one can easily discern the initial strike of the triangle. A triangle is a tough instrument to reproduce accurately due to its sharp attack time. It also changes harmonic content very quickly.
Violins were smooth and clear without any edginess. My audition recording for violin is EMI’s CDC 54753 2 6, which is Sarah Chang’s performance of Tchaikovsky’s First violin concerto. Clear, distinct, but not forward. Forward sounding speakers generally mean to me that there is a bump in the frequency response, not exactly desirable as far as I am concerned.
Woodwinds were smooth and powerful with great detail. I recall plainly hearing the breaths taken by performers as they played. The positioning was as precise in depth as it was in the right-left dimension.
Listening to Chabrier’s “Espana” and “Joyous Marche” (DG 447 751-2) was breathtaking and alive. “Habanera” was simply a delightful experience. For those that are unfamiliar with Chabrier, his music is very dynamic with a fair amount of bass drum and timpani. The brass is also very forward and prominent. These speakers reproduced the experience of a live recording to the point that I was left speechless for more than a few seconds. After the Chabrier selections had ended, the best I could do was to very softly exclaim “oh my!” That has never happened to me before. One could say it took my breath away but that is not entirely accurate. In reality, I was stunned to the point that speech now failed me just as my eyes had failed me earlier.
By now, the reality of the situation had struck home. All of my previous prejudices of what to expect regarding size, sound, and fidelity were now so thoroughly mangled, the only thing I could do was just close my eyes and listen. So that is what I did.
But what does it sound like? It doesn’t sound like much of anything. If one really had to press me for a description, I would admit that there are times that the Revealations sound like a cone based speaker, which is what they are. Is that bad? No. There are lots worse things than sounding like a cone speaker. Is it blatant and obvious? Not at all. One has to push very hard to describe the sound of these speakers. I did notice a couple of aberrations in the sound and imaging, but I believe these aberrations were a by-product of the listening room. The listening room was far from good and as a matter of fact it is among the poorer rooms I have auditioned in. Smooth bricks were on the right and large glass windows on the left. If a speaker system can perform well in that relatively hostile environment, then there is no reason why it should not perform superbly in a reasonable room.
Issues
The biggest problem a music fan will experience is the fact that a significant percentage of recordings are not mixed correctly. I am sure that many have experienced the “hole in the middle” effect and many speakers make this less objectionable. Not so with the IDS-25s. Due to the accuracy of this system, all of the problems with recordings will become quite clear and obvious. Just as a filthy car will show no scratches or rust spots, once cleaned these issues become glaring obvious. The same occurs with Roger’s IDS-25 speaker system. Recording mistakes and errors in judgment by the recording engineer become quite obvious. Even changes in recording engineers and their techniques become clearly audible.
Positioning these speakers is not something that is to be taken lightly. Toeing them in seemed to improve imaging and the sound stage. Distance is very important. Most of the DG recordings I listened to sounded better further away. Telarc recordings were better a bit closer and the EMI that I had was nearly hopeless due to poor microphone placement or mixing. Why? The strings section was thrown so far to the left that one had the impression that the focal point was in the conductors lap or even ahead of him. Not a very pleasant place to be as far as I’m concerned. However, I found this to be the exception and not the rule for the recordings that I listened to.
A couple of times I could hear a frequency dependent imaging issue where depending on frequency, the instrument would appear to center itself at the columns position. I believe this was due to a reflection from the very hard and very reflective sidewalls.
Summary
IDS-25s are everything Roger says they are; imaging that won’t quit with accuracy that will reveal the best [and worst] in your recordings. A neutral, effortless sound that is full extends to the deepest bass and highest treble and does so effortlessly. Details in the performance are now suddenly apparent, yet I experienced no fatigue during the entire listening session. Does it sound different than the XR290 or XRT22? Yes it does. My wife said that instruments sounded “clearer”. I do have to admit that for me to accurately assess them further, I would have to spend more time listening to them in my home than the short 6 or so hours I spent with them. These speakers would also make for a superb HT speaker as they have a small and unobtrusive footprint. They look very impressive without being ostentatious.
One could say the IDS-25s reproduce music so clearly it is as if a dulling haze has been removed from a painting. The difference is as obvious as comparing the ceiling of the Sistine Chapel before and after its most recent cleaning.
No subwoofer(s) needed or wanted here. Many will scoff at my last statement saying that a sub is necessary for proper LFE reproduction. All I can say is prove me wrong. Listen to the IDS-25s and compare that to a single or dual subwoofer system that is properly balanced.
Is this system perfect? No, but it is darn close. So close in fact, that the IDS-25s will be my next speaker system.
From R. A. 1-11-04
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