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Salk Sound SS9.5 speaker Review

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Finish: Special Gray

The driver set

Salk Audio has continued to hone its skill set making artful driver selections. Here, the Satori beryllium dome is used along with an Audio Technology midrange, neither one’s size specified on the website. The descriptions remind me of Kevin Hayes’ Valve Amplification Company (VAC), which eschews highly specified numbers in favor of general descriptions of the attributes. It had been a long time since I used a metal domed tweeter, the last one I recall owning being in the Kirksaeter Silverline 220 in use in the living room, and it had not the deftness of the Satori.

Jim offered some comments on the driver selection for this speaker, and in regard to the tweeter he states, “The earlier SS models relied on a custom version of the RAAL 70-20 tweeter, still one of the best ribbon tweeters available. The SS9.5 model uses a Satori beryllium tweeter. There are a number of advantages to beryllium. First, the cone break-up mode is at 34kHz – well beyond audibility. So, cone break-up will never cause the speaker to sound bright and edgy. Second, beryllium is self-damping. So, instruments like cymbals decay naturally and do not ‘ring out’ like other metal domes are inclined to do. Finally, the off-axis response of a dome is superior to a ribbon.”

I am a bit surprised at how much I like the beryllium tweeter. The presentation strikes the ear as being not as atomized as the RAAL ribbon, but it seems no less refined. It does not balk at the extended decay of cymbal strikes, or when revealing the friction in a bow pulling a string on a violin. Further, it has an appropriate output relative to the Audio Technology midrange. I listened at elevated levels to a variety of music, some of which in the past was strident through the RAAL ribbon of the Vapor Joule White, and I could not make the Satori scream at me. Those who have avoided metal dome tweeters can put aside their skepticism in this particular case. The Satori tweeter exceeded my expectations and restored faith in use of a metal domed tweeter.

Jim shares this about the midrange driver: “The midrange for this design was a custom project with Per Skaaning of Audio Technology. The Skanning family originally founded ScanSpeak and then Dynaudio. So, they are among the most experienced driver designers/manufacturers around. If you look closely at the midrange, you will notice it looks exactly like a Dynaudio driver. That is because it basically is. This is a very smooth and musical midrange with a bit more body in the lower midrange. So, male vocals sound a bit more realistic. While it is quite detailed, it is not as ‘analytical’ as some other high-performance midrange drivers.”

The Audio Technology midrange was a very pleasant surprise, as I have in recent years shied away from smallish midrange drivers. It is no secret to readers of my work that I enjoy the formidable mid-bass drivers employed by Legacy Audio’s largest floor standing speakers, the Aeris and Valor models. I doubted that a smallish midrange could summon the sense of ease of the 12” paper-coned concentric mid-treble of the Valor. However, the Audio Technology does pull off a surprising amount of ease, once again being mated superbly with the Satori tweeter. I think it is the best smaller midrange I have had in house.

The driver that to my ears is inscrutable is the Satori 9.5” woofer. I hear it, but not distinctly as a separate driver. With many past dynamic speakers, the bass driver is quite pronounced and easily locatable spatially, but not this one. The blending of the 9.5” woofer with the side firing passive radiators, akin to the Soundscape 10, is complete. Jim has shown his hand as a driver mix master, and has populated the baffle of the SS 9.5 in such a way as to maximize driver synergy.

Jim comments on the Satori bass driver: “Finally, you will notice that we use a single 9.5” woofer from Satori. In previous SS models, we either used a single woofer with relatively low sensitivity or, in the case of the SS8’s, dual woofers in order to increase the sensitivity. While multiple woofers will increase sensitivity if wired in parallel, the impedance drops and there is a certain amount of comb filtering where sound from each of the drivers intersects in space. With a sensitivity of 88 dB in this case, a single woofer suffices to move a lot of air down low.” The effect is a seamless transition from the 9.5” woofer to the side passive radiators, belying the appearance of the Satori bass driver with far deeper presence.

Here is what he says about the general design and the Satori woofer and twin side-firing 8” passive radiators: “The overall design concept was based on our success with the SS12, S10 and SS8 designs. All of these featured an open-backed midrange section and dual, side-firing passive radiators. Not only is there no possibility of port noise, but it performs well in even smallish rooms where a rear ported speaker playing this low may cause issues.” Jim likens the four 10’ side firing radiators to mini-subs that load the front of the room evenly. As we will see, placement in the room is important, depending on how much presence in the lower frequencies one wishes to experience.

Rounding out the physical description, the veneer had a semi-gloss finish and sculpted grills that affix with magnets to the appropriate locations on front and the two side radiators. The rear black plastic plate with the brass binding posts has poorly identified positive and negative indicators. I had to crouch down and use a flashlight to see them clearly to determine correct polarity, as the binding posts are brass, a good move for sound quality, but have no identifiers on them. One oddity in the build presented itself; on both sets the left/negative post did not allow full insertion of banana plugs. I tried two different brands of plugs, but the left post only allowed them to be inserted halfway. I am guessing this was a manufacturing defect of the company supplying the posts. This should be easily rectifiable by Salk Audio such that customers would not experience it. Nevertheless, there was enough penetration that the plugs did sit in the post and did not fall out. I noticed no performance shortcoming from the anomaly.

In discussion prior to the formal request for a review, I stated a preference for bi-wired speakers, but I had not made a firm request. I was anticipating using an additional two channels of the Legacy Audio i.V4 Ultra Amplifier, which would have upped the power to a glorious 2,400 total watts in use with the pair. With certain amps I might combine amplifier channels, but the differential design of the i.V4 Ultra prohibits it. In brief, each external channel of a differential amp design is akin to an internally bridged pair of amps. In a differential design four internal channels are bridged so as to exit the amp as a pair of L/R stereo outputs, but both the negative and positive carry a signal! There is no dedicated ground (traditionally the black post), so combining external channels is a no-no!

Even though with differential amps I cannot combine channels, I take glee in their technological advancement. Historically, when reviewing stereo amps that were bridgeable, I requested a pair of them in order to check out their bridged mono performance, and I typically found that performance soared when they were bridged. It did not always result in a new reference, as any given stereo amp may outperform any given bridged amp, and vice versa, but it did prepare me to appreciate the advantage of differential amps. Differential designs, such as the Pass Labs XA200.8 and the Legacy i.V4 Ultra, have convinced me that differential design is the way forward for amps, whether or not class D, which the Legacy amp is.


Schroeder method of IC placement and parallel speaker wiring

There are ways to juice a system’s performance beyond using multiple amp channels, and my primary ones involve doubling (placing in parallel two pair) the interconnects as well as the speaker cables. This does not combine amp channels, as I have just said that a differential amp drives all the output posts, and to sum multiple channels at the speaker posts would be potentially catastrophic to the amp. But in using a single set of amplifier posts one can safely attach two pairs of speaker cables in perfectly parallel position, assuring the leads mirror each other as if melded together when connecting the amp and speakers. There are certain amplifiers and systems where this may not be recommended; I am thinking in particular of low power amps and high efficiency speakers. If in doubt, consult the manufacturer. I normally use a set of spades and a set of banana terminations for convenience, but I have at times been able to use this configuration with two sets of spade terminations on the amp and speaker posts. Much care must be exercised to ensure that none of the spades are touching the spades on opposite posts! Doubling, or parallel, speaker cables help with many aspects of performance, including cleanness, warmth and spatial depth.

The more novel approach is my Schroeder Method of Interconnect Placement, and a pair of them requires four interconnects and two sets of Y cables. For each channel, L and R, place Y cables at both ends of the pair of interconnects. Note that XLR interconnects require a particular combination of terminations on the Y cables, such that one end of the joined ICs is male and the other female; a pair of single male to double female, and another pair of single female to double male cables are required. When assembled you will have a pair of doubled ICs! There is one caveat, that being the potential for an obscure interconnect design featuring high capacitance conductors (imagine an unwound foil of a spooled capacitor acting as the conductor), but such would be an anomaly in the world of interconnects. As usual, due diligence is required for this do-at-your-own-risk method.

In effect this approach doubles the AWG of the interconnect as well as the cable’s ground, and it makes a big difference in performance! I am now uninspired to use interconnects without Schroeder Method, as I find the result to be thin, even anemic. The Legacy i.V4 Ultra Amp responds readily to the Schroeder Method, and the SS 9.5 did as well.


Bombastic bass

Near the end of 2020, a side project with a set of vintage Ohm Walsh Model F speakers given to me in poor condition prompted a restoration. The restoration was what I would call a marginal success, not due to any deficiency in the replacement of the spiders and surrounds, but due to the speaker just not sounding great. After the initial euphoria of actually doing a budget restore of a Model F and hearing it for the first time, when I began to critique the sound, it was dull, had a constrained character, and the upper end was weak. I figured something fundamentally was wrong, and I continued to be bothered remembering what I saw when I had lifted the upper module, which houses the Walsh drivers, off the bass cabinets for the restoration. The bass bins were stuffed to the gills with heavy, dense foam that reached an apex a mere inch or two beneath the mouths of the drivers. How on earth can any driver sound normal when it fires into a cavity that presents quite limited expansion of air? The equivalent would be like shouting through a megaphone, but holding a thick pillow an inch in front!

I had not much to lose with this older speaker, so I tore out half the foam, opening up completely the upper portion of the cabinet and leaving the dense foam in the bottom half – a decision that could be reversed if ineffective. What a stunning transformation that had on the speaker! The dullish drivers changed fundamentally, providing what I had expected in the way of vibrancy, dynamic impact , a truly balanced and clean full range sparkle, and a more generous bass. It was a complete success. This was an instance where removal of wadding was entirely positive for a speaker and it salvaged the project, keeping the speakers from being pushed to the side and forgotten. The lessons in managing cabinet and fill material gleaned from this vintage speaker would be applied to configuring the SS 9.5.


Open back midrange feature

A somewhat similar assessment to the Model F’s cabinet and damping material episode was underway in regard to a feature of the SS 9.5 that hearkened back to the Soundscape 10: the open-backed midrange, incorporated in the upper cabinet of the SS 9.5. It seemed things were coming full circle, with much refinement of Jim’s designs over the past 8 years. The SS 9.5’s rear upper chamber comes with a moderate amount of light density (reminiscent of cotton candy) poly fill, and a choice of back panels for the rear opening; one is solid and the other is mesh, to allow either a traditional closed speaker or quasi-open baffle midrange setup.

As a point of clarification, not in an attempt to correct the manufacturer’s nomenclature, but for additional insight for the reader, both the midrange and tweeter are inside the chamber. Looking at the design of this baffle inside the speaker, which is easily seen when the light poly fill is removed, the majority of the Audio Technology midrange driver is not open to the rear, but the opening is occupied by the driver’s magnet structure. Even though the cone itself is not exposed, this opening would still allow a significant amount of the back wave of the driver to escape to the rear. The tweeter, which seems more exposed at the back, does however have its own backside, or housing. How these things affect the design of the SS 9.5, I will leave up to the manufacturer, but the fact that the result is a beautiful measured response is uncontestable. When the chamber is opened up, both drivers are contributing to the back wave propagation toward the front wall. The degree to which they are allowed to do so depends upon the amount and density of the fill used in the cavity.

I had used several side firing speakers previously, among the most memorable being the Chapman Audio T-77, but I was unprepared for such powerful bass from the SS 9.5, a bit too much. As I listened more closely, however, it struck me that the effect I was hearing was in the midrange to mid-bass region. I experimented to see what might happen if I attempted to dampen the cavity and block it with the solid cover. I pushed in the airy poly fill much closer so as to surround the tweeter and midrange backsides, as this would present no potential for damage to them. Incrementally I stuffed the cavity with additional cloth hand towels to fortify the poly fill in the cavity and further dampen the side walls of the chamber. I did so in four distinct phases, each incorporating more hand towel mass, and thus dampening the cabinet walls of the cavity and further reducing the rearward energy of the drivers. The effect was the midrange and mid-bass seemed to settle, or tighten. The more I stuffed, the more I liked what I heard, until a Goldilocks state occurred in which I could relax and accept the balance of cabinet and bass driver combination. At that point the LF seemed a bit too intense relatively, so I went one step further, repositioning the speakers such that they were more perpendicular to the front wall and aimed just wide of the respective ear (previously, they were toed in toward the respective ear). I much preferred these changes, which demonstrates superior flexibility in the SS 9.5’s setup and performance envelope over speakers without the option of the open-back midrange feature.

I was a bit surprised by this result because, prior to receiving the speakers for review, I was sure I would prefer the sound with the midrange chamber open. I have used many panel and open baffle speakers, so I anticipated that the light poly fill and mesh cover arrangement would be superior to my ears. Not so; I gravitated toward the more damped and solid back plate setup. Maybe it was my anticipation that the speaker had to sound more like a classic dynamic product, as I had been using the Vapor Joule White speaker for years as a reference. If the hybrid performance of the added front wall reflection and openness of the midrange and tweeter’s back waves are desired, the option is there for the taking. Conversely, if the speaker is to be placed closer to the front wall, or the front image is to resemble more closely that of a classic dynamic speaker, then the opening can be sealed.

I love options in audio products, and this is an unusual instance where the option, though valid, was not as preferable to me as the more traditional setup. I presume that such things will vary widely among owners. It is important to note that I consider the design of this speaker — having the option of the open chamber — to be positive. This is one aspect of the speaker that warrants continued experimentation, as such profound influences as the amount and density of damping material and placement of the speakers, and perhaps even the particular components and cables in use, could cause a shift in preference for it being open or closed. If the speakers are made available to me following the review, I will continue to explore the many options; this is a unique set of dynamic speakers, one I have a desire to use in reviewing. As seen below, there would be ongoing changes to the speaker positioning that elevated the performance further.

4 Responses to Salk Sound SS9.5 speaker Review

  1. Calvin Curry says:

    Please review the Songtower 2, BMR Monitors. Some of the Song 3 Series, etc. It is a shame that many people are not aware of Salk Speakers. I had the pleasure of meeting Mr Salk and his precious wife, when I was visiting my daughter at law school in Lansing. He gave me a tour and explained the different aspects of Salk’s way of building speakers. We listened to a set of speakers. Had a wonderful day there. They are special people.

  2. Calvin,
    God’s Joy to you,
    Thank you for the reply! I would encourage a colleague to review a smaller model of Salk Sound speaker. While I am still capable of muscling them about, I prefer to focus on tower speakers simply for the grandness of them. The day will come, but hopefully not for a while yet, when I will have to opt for monitors. But, you are right, more exposure would be a good thing.

    I also very much like the Exotica 3, and think that would make for a great review, perhaps by a colleague.

    Douglas Schroeder

  3. Richard says:

    Your comments force me to experiment with the solid back and additional stuffing for the mid-range chamber, which I’ll do this week. Thank you for that suggestion and the excellent review!

  4. Richard,
    God’s Joy,

    Thank you for your kind words!

    I hope you have a lot of fun and perhaps even get a tuning you really like! You an have more than one performance setting, if you wish.

    Douglas Schroeder

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