Tweeter: RAAL 64-10X OEM
Intermediate frequency: 2 x structure balanced mode radiator 2.5"
Linkwitz-Riley second-order acoustics at 850 Hz
Linkwitz-Riley fourth-order acoustics at a frequency of 3,800 Hz
A few years ago, in our evaluation of BMR Philharmonitors, we were shocked by the cost that Philharmonic Audio provided: an excellent bookshelf speaker with true full-range expansion and near-perfect on-axis and off-axis response. More importantly, its build quality and surface treatment are excellent, and it has reached the level expected for more expensive speakers. Unfortunately, shortly after our review was published, the sales of BMR Philharmonitors were put on hold. They eventually brought it back due to popular demand, but the price increased, although even at the current cost of $1,700/pair, we still consider it to be one of the cheapest products in high-fidelity audio currently.
Needless to say, BMR Philharmonitor has its fans, and we are some of them, so when Philharmonic Audio announced the BMR Tower, we were particularly interested in it. The basic formula is simple; use BMR Philharmonitor and tower it. However, as we will discuss in the design overview section, engineering challenges are not as simple as adopting BMR Philharmonitor and making it bigger. Despite this, Philharmonic Audio has now released BMR Tower, and they claim that it provides the same sound as BMR Philharmonitor, but with a wider dynamic range and deeper bass extension. It has a lot more speakers, and the price is $3,700 per pair. So, the question it naturally asks is whether it still has the same absurd value as BMR Philharmonitor? Let's dive into BMR Towers to find the answer...
BMR Towers arrived at my door in two large and heavy boxes. Lifting them is a challenge, and I encourage buyers to use a trolley to move the packaged speakers, or have a healthy partner who can help carry them. They are double boxed, each edge has a thick edge protection layer. Inside, there are four thick polyethylene foam blocks to protect each side of the speaker from impact. The speaker is covered in a cotton bag to prevent moisture and wear. The overall packaging is above average and close to the level of care I see on more expensive items.
After opening the package, the gloss of the speaker was better than I expected, which surprised me. These speakers are very shiny. I received Rosewood mirror finish, these speakers seem to be much more expensive than they actually are. They can also be finished in bright white or bright black. They have a flat front baffle with rounded edges, bent back to a narrow rear baffle, and there is hardly enough space for two vertically mounted terminal posts and tags with identification information. The driver is mounted directly on the baffle, not on the waveguide or mounting plate. The drives have a matte black texture and will not stand out visually, although I guess they will stand out even more on a white surface.
Philharmonic provides a grille covering the driver. The grille for each speaker is divided into two parts: one capsule-shaped part covers the midrange and tweeter speakers, and the other covers the woofer. In my opinion, these grilles look a bit strange and do not improve the exposed appearance of the speakers. I do think that speakers without grille look good. Grids must be the source of diffraction, so their only useful function is to protect the driver. If the driver is unlikely to touch anything in the environment where the speakers are located, it is best not to use the grille.
Much like its predecessor, the bookshelf speaker, the design of the BMR tower speaker is somewhat complicated. Naturally, some design elements are taken from the BMR Philharmonic Orchestra, but there are also some new problems that need to be solved. Engineer Dennis Murphy told me that the design of the BMR tower is more challenging than the BMR Philharmonitors. Let's start our design overview with the tweeter, the ancient RAAL 64-10X. This 64-10 is a newer design than the one used in the BMR Philharmonitor we reviewed, and it is said to have only half the distortion at higher output levels. To describe the tweeter, we will quote from the BMR Philharmonitor comment, because all the same comments still apply:
BMR Philharmonitor uses ribbon tweeters from the highly regarded Serbian manufacturer RAAL. Ribbon tweeters are usually installed on expensive speakers and are highly sought after for their linearity, detail, and high-frequency extension. What makes the ribbon tweeter so special? The answer is the low quality of the diaphragm. The working principle of a ribbon tweeter is to place a very thin conductive tape, which is usually a conductive trace on a material such as Kapton, or just a very thin aluminum tape in a strictly controlled magnetic field between two permanent magnets. When alternating current passes through the ribbon, it will vibrate as its magnetic charge rapidly oscillates between positive and negative. Proponents of the ribbon claim that they are better than domes as high-frequency reproducers because their moving mass is much smaller than domes, so they can accelerate and decelerate faster, and this faster movement makes the sound more realistic. However, ribbons have historically had some shortcomings. One of these shortcomings is that they are more expensive to manufacture, and they are fragile, so they are not as capable as high pitches in the mid-range. They also need a transformer to increase the electrical impedance to a usable level, which naturally increases their manufacturing costs and makes them larger components. BMR Tower solves the problem of low frequency vulnerability, just use the ribbon at the strongest high frequency and above, instead of letting it play outside the comfort zone.
BMR Tower uses two Tectonic BMR drivers and installs them in the MTM configuration associated with the tweeter. Compared to the BMR Philharmonitor, the additional BMR driver doubles the power handling capacity of the midrange, and since this is where most music "lives", this is a considerable advantage, especially for those who like to take a higher level The person who listens. The MTM installation arrangement is completed at both ends. It keeps the midrange and tweeters at equal distances, so any vertical off-axis cross zero point only appears in one frequency band. The mid-frequency driver will also greatly reduce the vertical off-axis dispersion, especially at the upper end of its bandwidth, which should better match the tweeter at the crossover point, because the ribbon tweeter has such a narrow vertical dispersion. Vertical off-axis cancellation should also reduce acoustic reflections from the floor and ceiling.
The Tectonic BMR midrange driver used by BMR Towers is an interesting technology. Again, we will quote the description of the BMR driver in the BMR Philharmonitor review, because it still applies:
"BMR" stands for "Balanced Mode Radiator". It is not an expensive component, but it is still a complicated project. It is an extremely wideband, flat diaphragm, 3-inch driver that uses a weighting ring on the diaphragm to significantly reduce cone breakage. When the deviation of the driver occurs so fast that the cone cannot maintain a consistent shape and starts to bend in various ways, cone rupture occurs. At sufficiently high frequencies, this happens to all drivers, and the result is that the response starts to be severely distorted beyond a certain frequency. The larger the cone, the lower the frequency at which the decomposition begins to affect the response. This is one of the reasons why the midrange driver is smaller than the bass driver, and the dome tweeter is smaller than the midrange driver. It has always been a challenge for speaker designers to filter out fragmentation artifacts, so any driver that does not have so many problems in this regard will make it much easier to design a good speaker. Tectonic's exact method of using its weighted ring to reduce breakage is quite complicated, but it is explained in this white paper.
For low frequency production, Philharmonic turned to Scan-Speak Revelator series drivers, which are the 8-inch bass drivers that Philharmonic used in their first speaker Philharmonic 3 in 2012. It has an unusually low 21Hz resonant frequency and is suitable for 8” drivers with 88dB sensitivity. This is a fairly sturdy motor part with a 2” thick magnet stack with a 5” diameter and a 2” diameter voice coil . It also uses a very light but strong paper cone attached to a cast aluminum basket. Its quality makes it an excellent choice for the kind of alignment used in BMR towers: a high-capacity transmission line. This type of transmission line does not use a box with a long and complicated path internally folded like a traditional transmission line. Instead, the woofer and port are placed in the correct position, and the box damping material is loaded at the correct position. So that the port produces output with a quarter wave of the driver output, instead of delaying the entire cycle like a traditional ventilated speaker. The advantage of the transmission line is that the loudspeaker can obtain deeper bass extension, and the driver loading is more precise, in order to better control the movement of the cone. Philharmonic claims that the speaker has a tuning frequency of 22Hz, which is much deeper than most seemingly "full-range" tower speakers, which rarely tap high power at 40Hz.
The crossover frequency from the bass driver to the mid-range is 700 Hz, and the crossover frequency from the mid-range to the treble is 3,900 Hz. The crossover circuit uses the Linkwitz-Riley second-order acoustic slope from the bass driver to the midrange and the fourth-order acoustic slope from the midrange to the tweeter. It is not a simple design, with a large number of bulky poly film capacitors, inductors and resistors. Obviously, in order to optimize this circuit, a lot of adjustments are needed. The relatively high crossover frequency can keep the midrange and tweeters away from the heavy frequency range and ensure that the BMR tower can perform louder playback without putting the driver in danger or causing serious distortion.
The shell is made of MDF and is well supported by two ribs and a window stay. It has a 1 ⅛ inch thick front bezel, and both midrange drivers have their own sealed compartments. Inside, except for the bottom where there is no filler around the port, the entire shell is filled with filler, and this type of distribution is required to perform a large-capacity transmission line design. All this is loaded with a fairly large 3-inch diameter port that is 9 inches long and has large bell mouths at both ends. The feet are brass cones connected to the ends of the discs by ball joints, so they should be able to adapt to most types of floors without any problems. I am very happy that the Philharmonic Orchestra has avoided the spikes that seem to be so popular in this field. The grille is not fragile and has some sturdy frames. They are connected magnetically, but as mentioned earlier, these grilles are only used to protect the drive diaphragm. They will not improve the sound, although they may not hurt it in any meaningful way.
In my 24' x 13' (approximate) listening room, I set up the speakers to maintain a distance of a few feet between the back wall and the side wall, and the distance between the speakers and the listening position is equal. I adjusted the angle of the speakers to face the listening position. The listening distance of the speakers is approximately 9 feet. The amplification is handled by Pioneer SC-55. No room correction equalization is used. No subwoofer is used.
As always, I started listening to speakers that focused on vocal music. For this reason, the first album I chose was "Little Kahuna" by Vana Liya. This new version is dominated by Caribbean music style, mainly reggae music, Liya's warm voice occupies the center of the stage. This is a piece of relaxing music, and Liya's voice is beautifully recorded and mastered, which makes this album an excellent demonstration material for hi-fi sound systems and a pure listening pleasure. How well can BMR Towers express Liya's talent and natural gorgeous voice?
When I started this album with BMR Towers, the first thing that impressed me was the vastness of the soundstage. Some percussion mixes span the channels, and on the BMR tower, they seem to span the width of my entire listening room. Liya's voice is firmly fixed in the center between the speakers, but the slight reverberation added to her voice makes her look like she is singing in a larger acoustic environment than my home theater room. As an album deeply rooted in reggae, because this kind of music is too relaxed and unable to exert force on the bass, the bass line is thick but not overbearing, and BMR Towers conveys the appropriate bass weight as the basis of the rhythm. Liya's voice, as well as the voice of the guest singer, sounded as rich and natural as the instrumental accompaniment. The entire album presents a uniform tonal balance, and it's hard not to let my heels pat with a catchy rhythm. There is no doubt that Vana Liya's future is bright. If more people can hear her music presented by BMR Towers, the future is indeed very bright.
When it comes to evaluating audio systems, few genres are as effective as orchestral music, because so many spectrums are used at the same time. If something is overemphasized, it is usually easy to hear sounds related to other elements of the recording. One of the orchestral pieces I decided to listen to on BMR Towers was the music score of "Zach Snyder's Justice League". The difference between "Zach Schneider's Justice League" and the first version of "Justice League" is particularly important because the scores are completely different. Danny Elfman composed the music for the first edition, and Thomas Holkenberg, also known as Drug Addict XL, composed the music for Zach Snyder's edition. Just like the accompanying movie, Holkenborg’s music is darker, heavier, and larger than Elfman’s score. One reason I chose it is because Holkenborg is not stingy in using bass in his score. This should be given to BMR Tower. Transmission line design is a shining opportunity. In fact, among composers, Holkenberg appears in our subwoofer review almost as much as Hans Zimmer.
The sound field reproduced by BMR Towers for the Zach Snyder Justice League soundtrack is refreshing, and the sound produced is lush and full of cinematic feel. The wide sound field created by the speakers gives the music a slight symphony hall effect, although it is undoubtedly recorded in the orchestra recording sound field. Therefore, apart from the occasional solo, there are not many precise imaging aspects in the album. The sound expected for such an epic soundtrack is "big". The dynamic range is also well executed, and BMR Towers can easily replay this exaggerated score at a vibrant level. The extensive use of bass drums does not cause trouble to the Reveller subwoofer, it can maintain the uniqueness of each bass element, such as drums, electronic bass cables, bass brass and bass violin. The subwoofer was not missed at all. They may be able to add more haptic effects at a higher SPL, but the sound produced by BMR Towers is very complete without a subwoofer. The spectral balance of the music sounds natural and realistic, and I haven't noticed any anomalies or abnormalities. The only strange thing I noticed is how deep these tower speakers can dig; they do have a subwoofer-like extension. Most seemingly full-range towers are not truly full-range, and do give up the lowest audible octave, but the BMR tower seems to capture the lowest frequencies contained in this kind of music. In general, Holkenborg's sheet music proved to be a pleasant listening on the BMR tower, and there is no doubt that orchestral lovers will love what these speakers do for their music collection.
For vocal works that are more complex than a single sound, I found a wonderful album called "Brabant 1653: Baroque Vocal Music from Brabant", played by everyone's favorite Dutch music group Holland Baroque. In "Brabant 1653", Holland Baroque shows the personality of 17th-century Dutch religious music and the extent of its development despite the differences between Catholicism and Protestantism. This record was released on the famous Pentatone label in the spring of 2021, with the highest level of production quality and played on Qobuz with a well-deserved 96kHz/24-bit resolution. High-fidelity audio was invented for such recordings; how good is BMR Towers turning these flawless performances into?
The sound field presented by BMR Towers is clearly presented, and it sounds like I am sitting in the back two rows of the chapel where the performance was recorded. Singer occupies various positions across the scope of the speaker layout, and each singer and instrument player is imaged with precise positioning. The atmosphere of the church is well communicated, and the reverberation seems to emanate outside the boundaries where the speakers are placed. The sounds of human voices and musical instruments are reproduced in exquisite detail. Everything sounds lifelike, without any timbre elements or even slightly exaggerated or dull. BMR Towers produced a neutral sound, but it would be foolish to mistake a neutral for boring; the performance was very lively, and I once again found myself surprised by the magic that a simple stereo system can create. These speakers seem to match this recording perfectly, and it's hard to imagine how it sounds better.
In our final comment on the speakers of the Philharmonic Orchestra, I wrote about my listening experience with Japanese artist Sayohimebou's album "Crystal Lamai". I think why not continue to do a good thing, and listen to another Sayohimebou album on BMR Towers, this time it is "Karaoke♫スターダスト Dongfeng", Google translated as "Karaoke♫ Stardust Dongfeng". This is a kind of dynamic and creative electronic music, almost free from the constraints of traditional music creation. Every studio effect filter in this album has been tuned to maximum, and the music relies heavily on sampling, even though the sampling source is out of its original context. In other words, this is a completely artificial music, unlike many music recordings that try to imitate a certain normal acoustic environment. Although listening to this album is like taking a train to Crazytown, there are ways to do this madness. I really want to know what it sounds like on BMR Towers.
From the very first moment of this album, BMR Towers depicted a scene similar to the intersection between sugary children’s cereal ads and re-contextualized modern art. The sampled sound pulls back and forth in the sound field, like an overactive cartoon character jumping out of the screen, but immediately appears on the other side of the screen. The phase technique used by Sayohimebou combined with the ultra-wide sound field projected by BMR Towers makes this musical schizophrenia seem to extend to the entire front hemisphere of my listening room. The characteristics of the speakers and the characteristics of the music enhance each other to create a truly unique sound experience, with multi-color explosions splashing layers of glowing neon paint on each exposed surface. This kind of music can also really suppress the bass, but BMR Towers can use the impact from the heart to eliminate the kick drum and electronic bass line. The precise imaging capabilities of the speakers are a treat, heard from an album by an artist who is almost completely indifferent to reality. Sayohimebou is definitely an acquired taste, but this kind of music is crazy in the best sense of the word, and BMR Towers makes crazy sound as good as possible. I can highly recommend these exquisite high-fidelity speakers to crazy music lovers all over the world.
In order to hear the performance of BMR Towers in terms of dynamic range, I decided to shoot a big-budget Hollywood action movie, a movie that I have not watched but promised some real sonic fireworks is "Mission Impossible 4 : Ghost Protocol". The "Mission Impossible" series has always been a reliable choice for those wild action scenes that are not too exaggerated to cartoonish. Such a big production must have some money to buy the best sound engineering. I adjusted it up for this viewing. Regarding the volume, the fourth "Mission Impossible" movie did not disappoint with the elaborate action movie and the special effects of the Reaper. This iconic theme song sounds great on BMR Towers. Most of the action scenes They are all reproduced vividly. The car chase in Dubai during the sandstorm is a notable example: as the turbocharged V8 engine accelerates, the deep wind is shaking. The launch of ballistic missiles from a submarine is another example: a thunderous launch The explosion sound is reproduced by the authority of the BMR Tower. For those who want to rock action movies, BMR Towers have demonstrated their capabilities, and their dynamic range is sufficient for daily household use. However, at the specified 86dB sensitivity, I may Will look for THX reference level dynamics elsewhere in a large dedicated theater room. I watched "MI:4" at high volume and did not notice any distortion or compression. I suspect that most users will reach their dynamic range limit.
To hear what BMR Towers would sound like in a more exotic mix, I watched the 2014 science fiction movie "Under the Skin". This Scarlett Johansson (Scarlett Johansson) movie combines erotic thriller and science fiction film together, has an almost experimental atmosphere, and has matching mixing effects. In this movie, Johnson plays an alien femme fatale who roams the streets of Glasgow, looking for lonely men, lures them to destruction, where they are swallowed. The plot may sound like B-rated movie cheese, but it is actually just an excuse to achieve a very special mood. To what extent does the BMR Tower help achieve the film’s emotional setting goals?
It turned out that the mix was simpler than I expected, but it still has a rich texture. Most of them sound like live recordings, which are more in line with the human experience than traditional Hollywood mixes. BMR Towers provides the immediacy needed for these scenes, even if everyone has a strong Scottish accent, the clarity of dialogue has never been an issue. But the most noteworthy element in the sound is undoubtedly Mica Levi's grotesque soundtrack, which sounds like a mixture of classic Gothic horror film soundtracks and avant-garde neoclassical soundtracks, using continuous minor strings. It is a disturbing experience to hear such accurate rendering that BMR Towers can do. If a word can summarize "Under the Skin" as an auditory experience, then the word will be distinct, and the BMR tower is sufficient to capture the unique soundscape embedded in this movie.
James Larson is Audioholics' main speaker and subwoofer commentator because of his in-depth understanding of speaker functions and performance, and his overall enthusiasm for the advancement of audio science.
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