In my initial review of the Legacy Aeris (Issue 235) I found that it was an excellent speaker for its price. The addition of the new Wavelet processor, however, makes a great speaker even better.
The Wavelet is a stand-alone electronic processing component that combines a DAC, a digital and analog preamp, electronic crossover, and far better room-correction features than were provided by Legacy’s original Wavelaunch processor for the Aeris. The end result is a combination that integrates electronics and speaker design in ways that not only do more to solve room-interaction problems, but produce cleaner and more musical sound at every dynamic level.
The Wavelet also provides the kind of defeatable adjustments in the bass and the lower midrange that should be in the electronics and not the speaker, and which can help make many recordings sound more musical and realistic. Moreover, the Wavelet is the answer to my one major wish for an improvement in the original Aeris design: It provides automatic set-up and room-correction adjustment features. In fact, they are a snap to operate.
The combination of the Aeris and the Wavelet are also relatively affordable by the steadily escalating pricing of the high end. The Legacy V that I reviewed in Issue 258 is the best speaker I’ve encountered with room compensation, but it costs $49,500—daunting even to most dedicated high-end audiophiles. Legacy has adapted the same Wavelet unit it developed for the Legacy V for use in the Aeris at a much more affordable $24,475. Moreover, users who already have the Aeris can buy the Wavelet for $4950, and the price for a consumer who wants to trade-in his original Wavelaunch processor supplied with the Aeris will be $3450.
Key Features of the Aeris
I’m not going to repeat most of the content in my initial review, but even a brief look at the photos of the Aeris in the Legacy website will show you that the it is one of the most attractive pieces of sculptured woodwork in audio.
To provide a short refresher course, its features include:
- A cardioid-shaped radiation pattern to decrease boundary coloration from sidewalls while decreasing modal sensitivity at low frequencies.
- Increased dynamic range and waveform tracing accuracy by employing drivers with higher sensitivity and greater acceleration. The high-flux magnetic motors of the midrange drivers are larger than on most bass drivers.
- The Legacy dual AMT (Heil) design employs a 4″ folded ribbon that hands off to a similar 1″ unit at the shorter wavelengths. The AMTs integrate with a high-efficiency 8″ midrange that together cover over seven octaves at a sensitivity of 98dB, and that I found helped produce something close to point source sound, in spite of the Aeris’ overall size, and to be smoother and more natural in the midrange and treble than any similar driver I’ve yet encountered.
- A titanium-encrusted 8″ midrange with an enormous motor structure imported from Italy.
- A 10″ mid/bass and dual 12″ subwoofers with a linear volume displacement of nearly 200 cubic inches. The bass section is powered by a cumulative 1000 watts of included ICEpower Class D amplification and offers exceptional extension to 18Hz. (Separate 500-watt full-bandwidth ICEpower amplifier modules are used for each of the 12″ woofers to reduce intermodulation distortion and prevent the user’s main amplifier from encountering up to 40 volts of back EMF generated by the Aura motor system used in the woofers.)
- Reverberation is minimized by reducing sidewall reflections via the radiation nulls to the side of the speaker. This open-air arrangement behaves as a dipole from 80Hz to 3kHz, summing into a cardioid pattern with the bass drivers in the band from 80Hz to 200Hz. Listening panels in controlled trials have determined that imaging precision and soundstage width is consistently improved over the Legacy Focus system, for example, which exhibits an otherwise-similar monopolar driver layout.
The Wavelet’s Key Features
The new Wavelet provides a far more flexible and capable package of electronics than the combination of the Aeris and the Wavelaunch electronics that I reviewed in Issue 235. The Wavelet is a full-featured outboard analog and digital preamp. It also provides automatic setup, including adjustment of the levels for its electronic crossover and channel balance, and far better room compensation than the earlier Wavelaunch—compensation that helps eliminate the coloration from unwanted room reflections.
The Wavelet includes two pairs of XLR and two pairs of RCA stereo inputs, and USB, RCA, and optical digital inputs for connection to an excellent 24-bit/96kHz DAC with switchable apodizing filtering. There is also an Ethernet port to keep the unit’s software and firmware up-to-date. Wi-Fi operated remote-control software can be loaded into a iPad or smartphone, and provides precise volume and balance settings as well as a number of other features most modern preamps lack.
Features also include easy switching between room-controlled and uncompensated sound, and settings for normal and reverse-stereo or mono operation. The unit also has four different settings for dynamic expansion, and one of the most practical equalization settings I’ve encountered. You can adjust playback as required to suit your taste or individual recordings. There are now four faders for bass-frequency contours centered at 50Hz, 100Hz, 150Hz, and 300Hz, a spectral tilt control hinging at 1kHz, and a brilliance control at 13kHz. The faders are visible on-screen at your remote and their effect is audible in real time. These controls are far more practical in compensating for the real-world differences in recordings than all but the most advanced parametric equalizers. The latest software update allows the user to store/recall up to eight different contour settings.
The Wavelet’s New Approach to Room Correction Software
The Wavelet does retain several important software features that were in the Wavelaunch.
Built-in software uses an algorithm to divide the left and right inputs with a customized high-pass and low-pass network to form a stereo two-way crossover. The transfer function for each loudspeaker is pre-programmed at Legacy for linear output from each driver, correcting minor anomalies inherent in the combined array. The output side of the matrix is factory configured for Aeris, the input side (left side of the matrix display in the software) is for you or your installer to make adjustments in your room.
Software includes an empirically derived algorithm that is integrated into the speaker design to compensate for the losses in low-frequency separation in most listening rooms by increasing the ratio of difference information in bass frequencies to more closely approximate half space (free space with ground plane).
What is radically different about the Wavelet, however, is that it debuts Bohmer acoustic processing. This is a system that can optimize the loudspeaker/room acoustic-transfer function in both the frequency and time domains. It uses a new set of algorithms, and starts with a psychoacoustically based measurement method with the provided calibrated microphone.
Alignments are then individually optimized within an unprecedented 40ms window by way of a setup using a calibrated microphone and wireless iPad, smartphone, or computer. The result is audibly improved transient response that allows the Aeris to operate accurately and consistently in any listening environment.
And here, let me stress a set-up feature that I failed to give proper emphasis in my review of the Legacy V. You do not put the mike at the listening position and try to average out what can often be serious variations in response in the bass with minor differences in microphone height, or if you rely on one seating position for setup, or try to create average settings over a wider area of listening positions. Instead you set the mike on axis with the Aeris’ tweeter at a distance of 48″ and then move it twice per channel—once to check phase and set the crossover and balance and once for room correction. I found the end result worked well with a wide range of speaker and listening positions, and produced consistently accurate measured results, where other units I’ve tested that place the mike in or around the listening position sometimes produce strange settings because the mike just happens to be in the wrong position. Moreover, no amount of tweaking the settings on the Wavelet to their extremes presented digital processing problems—something that can happen with room-correction devices that have more features than processing power.
The only limits I find to the Wavelet’s features that will have an impact on most audiophiles are first—like virtually every preamp now on the market—it does not include a built-in phono section. Second, it uses Wi-Fi for remote operation, and while it works well with a decent Wi-Fi system, I prefer to use a computer with a wired connection.
I should also note that the Wavelet does not attempt to get into the hi-res equivalent of the horsepower race at 384kHz and 32 bits. Legacy notes that “higher resolution files such as PCM and DSD can be readily played back through the Wavelet using software such as JRiver.”
In practice, however, I don’t find a limit of 192kHz/24-bits to be real-world limitation to sound quality. The room correction and other DSP processing in the Wavelet are very advanced. It uses an Analog Devices processor with an internal processing sampling rate of 96kHz and bit depth of 56 bits—a bit-rate that Legacy states is “56 bits of depth in a domain more than one trillion times finer in resolution than that of a standard CD.”
When it comes to actual recordings, I have not yet heard any reason to even go as high as 192kHz. Some of my colleagues disagree, but I have so far found rates above 96kHz/24 bits to be a waste of money. I do buy the 96kHz/24-bit version of the music I download or stream for safety’s sake, but most of the time, a good 16-bit/44.1kHz version of the same mastering of a recordings will sound exactly the same. One has to be very careful in paying what usually is nearly twice as much for the 96kHz/24-bit when there is no way to hear whether there is any difference, particularly with a modern DAC with really good filtering. Oddly enough, the better your DAC, the less likely you are to hear any difference.
As for streaming DSD, most DSD recordings have already gone through some form of PCM mastering before they are issued in DSD form. Moreover, I have yet to hear any comparison test that indicates high-rate DSD recording sound better than 96kHz/24-bit recordings. I do keep my SACD player, but largely because I love classical music, and the SACD versions on disc are usually a bit more detailed and have more musical upper octaves than the CD version on the same disc. However, to the limited extent that I have heard direct comparisons of DSD and PCM files that some of my friends have made of the same performance on high resolution systems, I have heard no more superiority from DSD over 88kHz–96kHz/24-bit than I have heard from 192kHz/24-bit over 88kHz–96kHz/24-bit.
As for the rest of the Wavelet features, it does comes with a small basic remote volume control, but what counts is the Wavelet app you can download for both setting up and operating the system. It provides exact volume and balance control, dynamic expansion and equalization settings, switchable room correction, and all the sophisticated control options I touch upon later. Just set up the wavelet for the form of remote control, leave it on continuously, and forget about the small remote entirely.
I should stress from the outset that the Legacy Aeris with the Wavelet is a very good speaker even without the room correction switched on. To repeat some key points from my first review, the treble and upper midrange are realistic without any softening or, contrarily, any touches of hardness. The treble from the dual Air-Motion Transformer (Heil) folded ribbon tweeter is extended and provides all the air I could want. Equally important, its transition to the mid frequencies of the “titanium-encrusted” 8″ midrange is virtually inaudible. Many of the designs I’ve heard that mix driver technologies have at least minor sonic anomalies in the transition areas between them and you can sometimes hear the difference.
Even without the room correction switched on, the Aeris will reproduce the midrange of my best piano and violin recordings with the kind of accuracy that is sometime missing in even the most expensive competition. It does equally well with flute and clarinet and soprano voice, reproducing the difficult passages in voice in ways that still shows the strain a given singer was under but that add nothing in terms of hardness or coloration. It does an unusually good job reproducing the most difficult instruments in the sonic repertoire, like the harpsichord, and it is as natural with cymbals as my recordings allow.
As for the bass, the Aeris will reproduce most of the bass detail that is actually on even the most demanding bass spectaculars. Saint-Saëns’ Third, the deepest organ music, Kodo drums, Telarc bass spectaculars, bass guitar, synthesizer, take your pick.
Switching on the Bohmer room correction makes improvements that are a matter of nuance, not a revolution in sound, and it can take a few minutes to realize that less room resonance is a good thing and excessive, lingering, peaky bass is not. But, there is no question that the new room correction option makes a critical difference.
The Wavelet’s room correction is subject to well-chosen limits and will not produce perfectly flat response at the cost of excessive correction. It can still compensate to a great degree, however, for really bad speaker placement in areas where there is too little bass or too much. It provides a capability that will make a vital improvement if you have a truly bad room, or you have to use a setup that is less than optimal because of the décor or other reasons. It does enough to get rid of the worst peaks—peaks which not only give the sound something of “one note bass character” but also excite room resonances and mask the midrange, the highs, and the details of the rest of the bass.
What is even more important to me, however, is that it also produces major sonic benefits even in a good room and a good location. The bass is much tighter, and transients are far better defined. You can hear the full range of bass without dominant peaks and fewer apparent suck-outs. Higher-level dynamics are cleaner, particularly in the bass. The Aeris does not have all of the power and bass detail of the Legacy V, but it can overdrive my room at every bass frequency that is musically relevant. Adding the Bohmer room correction means that the overall sound is much cleaner at higher volumes. There are fewer room-boundary problems, where higher bass levels mask the rest of the music to some degree or are too sustained to sound realistic. Room correction not only provides great bass detail, it does so more evenly.
The critical transition from the deep bass to the midbass is cleaner and more musically natural, as is the transition from upper bass to the lower midrange. This allows the Aeris to do a better job of cleanly reproducing the natural warmth of music that is present in good recordings and doing so more accurately. The middle and upper midrange and the treble become clearer when the hills and valleys in the bass response, and excess room resonances, are reduced. This is something I’ve also noted in really good speakers without room correction and that measure exceptionally smoothly in the bass in a given listening room. Getting the bass right is critical to getting the best in midrange and treble sound.
Soundstage detail and depth become cleaner and more detailed, and imaging becomes notably more precise and natural in many recordings. The Aeris’ soundstage is very good even without room correction, but the speaker seems to act more like a point source with room correction engaged.
The combination of the Aeris and Wavelet provide some of the most musically realistic sound I’ve ever encountered. They take digital processing and room correction a vital step forward, and show they can reach levels that are competitive with even the best purist speakers.
The ability to make firmware upgrades, as the interview attached to this review with Bill Dudleston (the chief designer of the Aeris) indicates, will lead Legacy and Bohmer to make steady improvements in processing, operating, and set-up features, and don’t forget, as you look at the price, the Wavelet is also a really good analog and digital preamp and DAC as well.
If I now have a new wish, it’s to hear what the Bohmer level of correction can do when applied to other brands of speakers. As the interview indicates, this is another wish that may end up being granted.
Specs & Pricing
Type: Frequency- and time-domain-optimized 4.5-way loudspeaker with directivity controlled array
Tweeter: 1″ AMT neodymium ribbon
Upper midrange: 4″ AMT neodymium ribbon
Midrange: 8″ cast-frame, titanium-encrusted diaphragm, dipolar configuration (open baffle)
Midbass: 10″ cast-frame, carbon-fiber/pulp diaphragm, dipolar configuration (open baffle)
Bass: Dual 12″ aluminum diaphragm, Aura neodymium motor, sealed enclosure
Frequency response: 18Hz-30kHz +/-2dB
Impedance: 4 ohms
Sensitivity: 95.4 dB @ 2.83 volts1m in-room
Recommended amplification: Bass section is powered internally with dual 500-watt ICEpower amplifiers; 30 watts or greater required for upper section
Crossover: 80Hz, 2.8kHz, 8kHz
Inputs: 1 pair of external binding posts, 1 XLR balanced inputs
Dimensions: 14.5″ x 58″ x 16″
Weight: 171 lbs.
AHC Talks with Legacy’s Bill Dudleston
Let’s talk about the future of both your efforts in room correction and plans for the Wavelet. Any plans for a universal version of the Wavelet that could handle any speaker, including ones with a single input?
Yes. An example is already in the works. We are introducing a 750-watt flex-powered version of our Focus speaker, which can be driven three different ways; mono-amplified internally with a single input, bi-amplified with internal crossover, and bi-amplified with the Wavelet crossover. In all three variations the Focus XD can employ the room correction. To correct a generic speaker with a single input, we will offer a basic menu of target function choices, including excursion limit protection at low frequencies, and request the user input the best fit of the speaker’s radiation pattern (e.g., omni full-range, omni bass with cardioid upper range, and dipolar). Another parameter to be input will involve the number of subwoofers in use if any.
If we can switch back to the Legacy Aeris and Wavelet, what adaptations from the room correction for the Legacy V did you have to make to suit the Aeris?
The room correction process remains the same with a very similar target function as the V. However, building the V system from the ground up using the Wavelet revealed several areas where we could get more performance from the Aeris in the crossover region and in driver correction. Aeris is more coherent with the Wavelet in place before the room correction is even applied.
How is your approach to room compensation evolving? Have there been changes since the Legacy V review and what changes are you exploring? Will they all be possible through software changes?
Most of the recent improvements to the software have been made to improve setup and user control, such as the polarity check and level adjustments. We are now looking at the upper range of the reverberant field more closely. Here the density of reflection, spectral balance, and relevant temporal information are being studied along with the psychoacoustic weighting of this information. All improvements will be available through software updates downloaded to the USB stick and inserting in the Wavelet port.
The remote control features and software download commands are now accessed via Wi-Fi. Do you have plans for a wired network connection to realize software updates?
The prototype Wavelet originally hosted its own network, but this prevented the continual improvement to the remote interface and functions. The current method provides many advantages include control of multiple units simultaneously. Software updates will eventually be offered from the Legacy website, regardless of what port is used. Users will be allowed to subscribe to updates for a modest fee to keep the programming current.
Any potential for Wavelet to adopt MQA or higher sampling rates?
That really is a DSP question. The Wavelet will presently accept PCM files rates at high as 352.8kHz and higher. But remember Wavelet is not just converting a single sample of data per unit time, but correcting a 40msec window. This is equivalent to 14,080 samples to applying complex computations upon in real time.
A sampling rate of 96kHz is more efficient, consuming less processing power and sonically equivalent in the end. Think of a digital photo. A sharply focused image at 150 dpi will provide more real detail than a slightly out of focus image at 300 or 600 dpi. That is why it is the role of the Wavelet to sharpen focus in the time domain at 56 bits and then use apodizing to remove digital artifacts.
As you know I am a strong believer in the workings of Bob Stuart’s MQA. I think if audiophiles experienced it, even if they didn’t comprehend the genius of the solution it offers, they would realize that sonic improvements are not to be had by merely increasing sample rates. I hope the press gives MQA the attention it deserves. The consumer must demand it for the format to gain acceptance.
We would then most certainly consider a license. While I will personally always record live in WAV, MQA is the best solution yet proposed to deliver music to the audiophile. No compromise in dynamics, noise floor, or audible bandwidth, yet file size is similar to a 16-bit WAV file. It is certainly a great replacement for FLAC, DXD, DSD, SACD. Today, music should not even be distributed in MP3, AAC, WMA. These formats should be used in talking appliances.
Your literature describes the way the Wavelet reduces room reflections, but does not describe frequency correction. How does the Wavelet do this?
First the loaded algorithm corrects the loudspeaker frequency anomalies in each channel of output, independent of the room. Let’s say we have a shallow dip at 1800Hz, for example, but next to it is a sharper rise in response at 2200Hz. Previous methods would apply a broad boost at 1800Hz, and a sharp cut at 2200Hz using filters that introduce phase shift. While this can make the frequency response appear smoother at a single mike position, the ear is aware something is still wrong in the time domain and the power response. Time domain measurements substantiate this.
The Wavelet applies a totally different approach. First of all, it will not force the frequency response flat at the expense of transient behavior. It will address the cause of the problem and make a psychoacoustic correction weighing the time domain heavily. The Wavelet’s software will identify domain errors introduced by stored energy in the diaphragms, which are ultimately the actual cause of the peaks and dips. It will undergo iterative calculations to determine the most optimal solution with regard to phase to preserve transient response. It may apply a gentle lift if energy is lacking, or remove a resonance in the diaphragm material but the time domain will always be improved in the process.
The room correction continues in the same manner, with emphasis on treating errors introduced by boundary interaction. It does not merely notch response due to room resonances. It instead works to prevent these resonances from forming by looking for late arrival of redundant information in the measurement process. Resonances take quite a while to build up. Even a simple floor to ceiling axial resonances requires at least 16msec to form. The problematic buildup from the wall behind the speaker usually requires less than 8msec in comparison.
This old information is predicatively and literally fed forward in time, canceling its own presence. It is not accomplished relative to a position or multiple averaged positions in the room but relative to the launch from the speaker itself. It is unique in this manner. The process really should be described as automated loudspeaker adaptation instead of room correction. We didn’t change the room a bit!
By Anthony Cordesman
I've been reviewing audio components since some long talks with HP back in the early 1980s. My first experiences with the high end came in the 1950s at the University of Chicago, where I earned part of my tuition selling gear for Allied Radio and a local high-end audio dealer, and worked on sound systems for local night clubs, the Court Theater, and the university radio station. My professional life has been in national security, but I've never lost touch with the high end and have lived as a student and diplomat in Britain, Belgium, France, Germany, NATO, Asia, Iran and the Middle East and Asia. I've been lucky enough to live in places where opera, orchestras, and live chamber and jazz performances were common and cheap, and to encounter a wide range of different venues, approaches to performing, and national variations in high-end audio gear. I currently hold the Burke Chair in Strategy at the Center for Strategic and International Studies, and my open source analyses are available at that web site. What I look for in reviewing is the ability to provide a musically real experience at a given price point in a real-world listening room, and the ability to reveal the overall balance of musical sound qualities that I know are on a given recording. Where possible, I try to listen on a variety of systems as well as my own reference system.More articles from this editor
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