Excellent midrange, huge soundstage, good bass extension, heavenly treble, good integration of the woofer with the ESL panel

Narrow sweetspot.

I have these beauties for a year now. The best speakers for $5k or less! I'm still amazed at how nice they sound every time when I sit down to listen to music.

Associated equipment:
Audiomeca Keops CD player;
InnerSound preamp;
InnerSound ESL amp;
InnerSound Isis speakers;
Tara Labs Master Gen. II interconnects/speaker cables

Similar Products Used:

ML SL3, Meadowlark Shearwaters, Maggies 1.6

Spectacular soundstage and precise imaging, incredible clarity, transparency, and speed, good bass extension and pitch, good integration of ESL panel with transmission-line woofer in midrange, nice looking (IMHO), and not too big or heavy.

Small sweet spot, somewhat loose bass, and some high frequency treble emphasis.

These ESL/dynamic hybrids are excellent speakers in most respects. For the money, they are quite remarkable. After reading the very positive reviews on this website and in various audio-rags, I did an in-home 30 day audition of the InnerSound Isis speakers, together with their ESL amp and preamp. I was particularly influenced by Jerie’s comments about the speakers (see below) because, like him, I had spent many happy years with Apogee Stages driven by a Rowland Model 1 amp and a tube preamp (in my case, the Audible Illusions Modulus 3A). Since we obviously had similar taste in audio equipment, it seemed pretty likely that if he’d liked the Isis so much, I would too. He made some crucial comparisons between the Isis and the Stages that gave me enough interest to ask for the home trial.

When properly set up (aiming directly at the listener in nearly an equilateral triangle arrangement) and fully broken in (I’d say 50-100 hours minimum) with first-rate electronics feeding them and well recorded source materials, these are truly reference class speakers in their spatial and temporal resolution. (And that’s saying quite a lot, considering their modest $2700 price!) They throw a 3-D image as well or better than any other speaker I’ve heard, including highly touted imagers like the Dunlavy SC IV/As. On disks I’ve played hundreds of times before, I heard radically new spatial information through the Isises (the plural of Isis is what ... Ises???). On Bobby McFerrin and Yo-Yo Ma’s “Hush” album, for example, sounds that had been localized through the Stages and De Capos indistinctly in the middle or on both sides simultaneously now bounced deftly left and right, arched upward over the top, or did cartwheels around the room. The decay of sounds in a natural acoustic and their reflections off back and side walls were also clearly and accurately portrayed, giving a vivid image of the recording space.

The same level of accuracy and clarity was evident in their transparency and inner detail. I could hear individual bristles on the brushes striking cymbals, separate singers within a 40-voice chorus, and tell how much lipstick Ella Fitzgerald was wearing when she recorded a song. The whole soundfield had a clarity, vividness, and solidity that was almost unnerving, especially at night when I listened with my eyes closed. I could do this for hours, usually with a big grin on my face as I experienced the expansive sonic landscape that these speakers created in my listening room.

The integration of the ESL panel with the transmission line woofer is quite smooth and nearly unnoticeable in the midrange transition zone. You can easily tell, however, that the quality of the low bass is not the same as the treble because it isn’t nearly as fast and has boxy resonances that are absent in the ESL panels. The bass goes pretty low (I’d guess to mid 30 Hz or below) and is always tuneful, but it is too loose and resonant at the bottom for my taste. String bass, for example, often sounds too much like an electric bass guitar because it doesn’t start and (particularly) doesn’t stop the way it should. I ought to add that the Innersound ESL amp drives these woofers with more authority than the other two amps I tried (a Rowland Model 1 and an Audio Valve Challenger tube amp). And it can make the Isis go as loud as I could stand without distorting. It’s one powerful little amplifier (300 wpc, but in a smallish and light package that runs very cool).

Even so, I decided in the end not to buy the Innersound gear. It wasn’t the small sweet spot that bothered me. I always listen alone and from one particular chair, and I have no desire to wander about or listen from elsewhere. Nor was it the loosish, resonant bass. My main problem with the Ises was their high-frequency emphasis bordering on aggressiveness that intruded on some (but not all) recordings. I noticed it particularly as a hardness in loud passages with the upper ranges of horns (both brass and woodwind), cymbals, piano overtones, and vocal sibilants. It isn’t distortion -- the sound you get is very clear and clean -- it’s just too much of a good thing for my taste. Combined with the strong bass, the treble emphasis made the midrange sound a bit recessed to me. I fiddled with the level control on the back of the speakers that adjusts the relative strength of the bass, but couldn’t get that to fix the problem I was hearing.

Since I hadn’t read about any high frequency problems in any of the reviews I’d seen, I thought it must be something else in my system. So I spent many hours swapping different versions of everything into and out of the system: 2 preamps (the InnerSound and the Modulus 3A), 3 amps (the ESL amp, the Rowland, and the Audio Valve), 4 interconnects (Goertz silver, XLO Pro 150, Kimber PJB, and RadioShack), 2 kinds of speaker cables (Symo and Radio Shack 12 gauge speaker cord), 2 different power strips, with and without a PS Audio Power Plant in the chain. Subtle differences were audible, but nothing overcame the high frequency emphasis I was hearing.

So in the end, I sent them back to Innersound. Roger Sanders, the owner, was surprised that I had this problem with the HF end, but was gracious and helpful about the return. I wish they had worked for me because they have a lot going for them, especially at their price point. I still think they are a five-star value, but I can only give then four stars for their overall sound because of the problems with the low and high frequencies that I described above. For those who like a slightly etched sound on top and don’t mind some looseness in the bass, these would be spectacular speakers for the money.

Similar Products Used:

I have owned VMPS Towers, Vandersteen 2Cs, Magnepan IIIAs, Apogee Stages, and Reference 3A De Capos; I’ve auditioned several Martin Logans, Thiels, Dunlavys, Ariels, Alons, etc.

image, clarity, "presence"

takes serious equipment to push them

I spent about 3 months auditioning speakers for a new house that I just moved into (much larger). The ISIS speakers were by the far the best available within my price range. Because of the size of the room that I now have my equipment in (30+' x 20+') I focused in on speakers like the SL3 from Martin Logan and 3.6 from Magneplanar. I tried a few conventional speakers such as the Vandersteen 3 signature, but felt that ESL was better suited for my needs. Although I was impressed with the Maggies, a six month waiting list and a need to spend a large amount of money to drive them was too much for me. The ISIS Although requiring a good deal of power is much more forgiving than the Maggies. There is no comparison with regard the SL3's, the ISIS is better in all categories.

Another pleasant note was the customer service that I received from Inner Sound. Having an opportunity to speak directly with the designer of the speaker and to have him honestly (in my opinion) answer questions was a unique and new experience for me.

Similar Products Used:

listened to Martin Logan SL3, Maggie 3.6
owned Vandersteen 2c

Incredible Soundstage, detail, dynamics, build quality, customer service

Relatively narrow sweet spot for critical listening, however off axis casual listening is very clean

InnerSound's ISIS speakers are truly incredible! InnerSound uses the term "Magic Show", but underneath, there's really no magic, just some of the finest engineering and quality components put together by the man who wrote the cookbook on electrostatic speaker design, Roger Sanders. Perhaps it seems like magic that a speaker can make a recording sound so convincingly real.

I had been on a quest for years to find my ultimate audio speaker. I figured that when I found it, I would instinctively know. I expected that I would get a goose bump feeling like some people describe when they are in the presence of a great live performance. You know, horns having that sharp brassy edge that almost makes you grab your ears but after a few moments you know it's right, or those hard hitting dynamics that make your eyes blink and your heart beat faster. I have listened to speakers costing anywhere from $500 up to $20,000 (not that I could ever afford them). I thank all of those sales people for their time and effort, some just short of holding a gun to my head. I learned an incredible amount about speakers, recordings, oh yeah, and wires too. Many times I thought I was getting close, but I would read about another speaker and would want to wait until I heard it. I was so frustrated that I did nothing for a long time and now I'm very glad.

Then by chance, one of my non-audiophile friends at work told me about a company that his neighbor helped start. It was called InnerSound. He mentioned something about hybrid electrostatic speakers. It got my attention enough to make me do some checking around on the internet, after all, just about every speaker manufacturer has something to say about how their speakers compare to electrostatics and electrostatic manufacturers compare their ESL's to other brand ESL's. I called the sales phone number listed on the InnerSound website to see where I could audition these speakers. The factory just happened to be close to where I live, so I drove over and auditioned the EROS speakers with their exclusive bass amp and active crossovers. I got the goosebumps. It was without question a performance that I will never forget. The designer, Roger Sanders, was very informative and had a gift for explaining technical aspects to people who are not very technical. I went home in love. I couldn't stop thinking about those speakers.

After a few days, my practical thinking kicked in and I began to question if it was merely my imagination. I visited a few other audio stores where one owner actually told me "What your problem is - is that you need a reference sound in your head". That's when I was shown the $20,000 Avalons hooked up to about $50,000 worth of hardware. Guess what? The music was coming out of some very gorgeous, expensive boxes, and it sounded like boxes. I waited a few more months thinking that this was just a short obsession and it too shall pass. I reasoned that the EROS speakers were just a little out of my price range and they definitely would not fit in my living room, but I could not leave it alone. Finally I called again to see if I could listen to a pair of the ISIS speakers (the little sister of the EROS). I spoke with Roger again and arranged for a demo. I expressed concern that my inexpensive Hafler 9290's may not be able to drive the ISIS if I decided to purchase them. Roger suggested that I bring one of the Haflers over. So I packed it in the truck and off I went. On the way over, I kept telling myself that these are going to be disappointing compared to the EROS. Man, was I wrong! Once again I found myself totally in awe of the sound that flows out of these speakers. Roger has done a phenomenal job of integrating the bass driver with the electrostatic panel. The transmission line architecture of the bass driver integrates so well with the electrostatic panel that it results in a seamless spectrum of music right down to the frequency where Polygrip starts to lose its hold. The demo was setup with my Hafler running the left channel speaker in bridged mode and his InnerSound ESL amplifier running the right speaker from its right amplifier section. After a little tweaking for power differences, the show began. He played many types of music at center seat, front row, concert levels (and these things will go to concert level). Finally, at nearly ear splitting levels, the Hafler began to clip audibly and we backed off. I was very pleased how well it held its ground. Roger confided that in his younger years he owned several Hafler amps because of their ability to deliver high current and drive highly reactive loads, which are an inherent characteristic of electrostatic speakers. After that demo, I knew I was out of excuses except for maybe just one. My wife told me not to bring home any more "all black" stereo stuff. I asked Roger if InnerSound offered any finish options. Roger explained that InnerSound had experimented with different wood trims, but decided not to pursue it because they really preferred the clean, high-tech lines of the black anodized aluminum. However, Roger said that for about $100 more, he would have his cabinet builder make custom trim. Instantly I agreed and we shook hands on the deal. Overall, it took about eight weeks for my speakers to be completed due the cabinet builder moving into a new facility. When I went to pick them up, there was a nice surprise. InnerSound's cabinet builder had created a selection of various wood trim options. I had asked for medium oak, but in addition, there were dark cherry, light oak, and a very interestingly grained poplar. All of the finishes were superb. At the last moment I changed my mind and opted for the poplar, so Roger had the assembler put the wood trim on my speakers and supply me with the original anodized aluminum "just in case I ever change my mind" (talk about customer service!)

As they were wrapping my speakers for transport in the back of the truck, one of the employees stated that she would really like to hear back from me about the WAF once I got them set up in my house. "WAF?" I was embarrassed. I was not familiar with this audio term. "WIFE ACCEPTANCE FACTOR", she said. As it turned out, she was Roger's wife and she was campaigning to make the wood trim part of InnerSound's new finish options.

Well after a week, I can tell you that the WAF is relatively high. My wife said the wood is a very nice touch, but what surprises me most is that my wife, the one who claims that she can't hear well enough to appreciate good speakers, suddenly has an interest in why it sounds like lead guitar players are standing on our coffee table and why Andrea Bocelli is singing only to her.

Similar Products Used:

I have not owned anything that could compare. I considered Magnepan MG-1.6QR, Martin Logan Aerial, Meadowlark Shearwater Hotrod

Soundstage & Imaging, Dynamics, Speed of Attack, Transient Response and Detail in Spades

Normal ESL stuff, fussy to set-up and room dependant.

The Isis speaker is Inner Sounds "little sister" product offering of the Eros. It is a hybrid design employing an electrostatic panel measuring 11.5 inches wide by 42 inches tall. This panel is mounted above an 8 inch dynamic woofer mounted in a transmission line enclosure. Overall the speaker measures 62 inches tall and sits upon 3 adjustable spikes or hardwood floor "smooth" feet for solid anchoring. Speaker terminals consist of two sets of quality constructed binding posts that are located to the rear of the speaker. One set of binding posts for the ESL panel and the other for the woofer to facilitate bi-wire or bi-amp setup. The speaker also comes with shorting straps for the speaker terminals to support conventional wiring. Below the speaker terminals is the AC plug for the detachable ESL power cord and above is a bass level control knob. This knob has 4 settings ranging from -2 to +1. The speaker manual is superb with outstanding documentation on speaker setup. Most reviews states that these speakers are highly directional producing a rather small "sweet spot". I have found this to be true with most ESL and ribbon panel loudspeakers.

I have lived very happily with a pair of updated Apogee Stages for the past 10 years and in all that time I had never found any loudspeaker worthy of removing them from my listening room. In the past 6 months my girlfriend and I have auditioned the 3.6 maggies and Martin Logan CLSIIz, SL3, Request and Prodigy loudspeakers. Of these speakers we both felt than only the Prodigy, at $10,000 a pair, offered a significant upgrade over the Stages. We purchased the Isis two months ago and have never looked back. Much like the Stages and ESL speaker offerings, the Isis are fussy to setup being highly room dependant. However, straight out of the boxes the Isis let it be known that these speakers are a very special product indeed. Dynamics are absolutely superb. These speakers have a speed of attack that bring a whole new meaning to the term transient response! Unlike most of the Martin Logan products, no ill defined lagging base or rolled off highs here! The Isis slaughter everything in the Martin Logan product line from the Request down. I have a good sized listening room and eventually ended up placing the speakers 54 inches from the rear wall and about 3 feet from the side walls putting the speakers almost 8 feet apart. This really opened up the 3 dimensional sound stage producing astonishingly detailed, timbre correct inner dynamics. Imaging is exacting with clearly defined space between instruments. If you are an inner detail freak these are your speakers as they will deliver musical nuances in spades! Leave the lights on at night! It is important to read the manual on speaker set-up, but don't be afraid to experiment on placement as all ESL designs are highly room dependant. To a greater degree than the Stages, these speakers are terribly revealing of cables, interconnects, electronics and badly recorded music. Be careful what you feed them. Given the correct amplification these speakers will play very loud without distortion and cast a vast soundstage in a very large room. For amplification I would recommend an amp with high current that can drive low impedance loads. These are ESL's and they love lots of current. Choose a speaker cable that can deliver the goods. Bi-wired set up yields superior sonic performance. Cardas Golden Cross works well but the Kimber Bi-Focal XL yields superior results. I would also highly recommend bi-amping or bridged amplification for these speakers. The difference is not subtle. I also believe it is important to do business with a company that is focused on the customer. Inner Sound has proven that to me. They get 5 stars for customer support.

On a final note, most of the reviews about this product crow about what a "good sonic value" the Isis is. I suppose you could look at the Isis that way. The truth is the Isis is a serious sonic contender regardless of price. The fact that you can purchase this high end ESL for a song is purely bonus.

Anthem CD-1 CD Player
Sonic Frontiers Line 3 Pre Amp
(Two) Roland Model One Amps (Bridged @ 240 watt 8 ohms each)
Kimber Bi-Focal Speaker Cables
Nordost Red Dawn Interconnects

Similar Products Used:

Apogee Acoustics and Martin Logan product offerings