Explorations in Audio

Karsten Hein

Are you ready to Explore?

In 'Explorations in Audio' I aim to share some practical insights on setting up and optimising an affordable HiFi system. Although one would think that, really, all has been said about HiFi, some surprisingly simple questions still remain, e.g.: 'Is digital superior to analogue?' 'Do cables matter?' 'Can digital cables pick up interference?' 'Should speakers be placed on spikes?' 'Has evolution in HiFi made older gear obsolete?' 'Where should I place my sub?' 'Which room correction works best?' - On the other hand: 'Are these really the right questions?' - We shall see.

What’s new in eiaudio?

While the entries in this blog are divided into the three distinct categories above, you will find a mixed listing of the most recent postings below. The most recent article is shown first. If this is not your first time visiting, the listing below is a good place to quickly check if anything is new.

Your input is more than welcome, as long as you follow the basic audiophile rule of ‘ear over mind’. This means that you do not comment based on what you think you know, but only on the basis of your own listening experience. Please feel free to suggest gear for testing as well as leave comments on the descriptions provided here.

  • Madrigal Flat Copper Core

    Madrigal Flat Copper Core

    1/19/2022

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Speaker Cables

    Madrigal Audio Laboratories was founded by Mr Sanford Berlin during the mid 1980s and took over Mark Levinson, the manufacturer of high-end audio products, in the same year. In the company's nearly 20 years of existence, Madrigal owned a number of famous audio brands, such as Audioaccess, Proceed, and Imaging, who developed and produced some outstanding Hi-Fi products, before Madrigal was ultimately absorbed by the Harman International Group in 2003 and saw its headquarters closed down later that year.

    The loudspeaker cables shown here were manufactured by Madrigal Mark Levinson during the late 1980s, most likely in an attempt to answer the question of how speakers would sound if they could be integrated directly with the amplifier's circuit board, rather than being connected by means of sound-compromising speaker cables. This notion may seem perfectly understandable to an audio engineer, but it perhaps needs some explanation to be fully appreciated by those outside the industry.

    Right from the first gramophones, audio reproduction had originated from a single source that transmitted its signal directly to some type of transducer. The first radio receivers were of mono design, and their loudspeakers were integrated with the electronics. It was only with the advent of stereo listening that loudspeakers needed to find their own place further away from the electronics driving them. People listening to broadband speakers connected to their home stereo setup during the early 60s may not have noticed the loss of signal integrity so much, however, as loudspeaker cabinets, crossovers, and driver technology became more sophisticated during the 1970s and 80s, the design imperfections of loudspeaker cables were gradually being exposed.

    Manufacturers of audio equipment such as Madrigal Mark Levinson had an interest in demonstrating the benefits of their improving technology to their customers and noticed that some portion of their research was lost even before the music signals reached the loudspeakers, simply due to the fact that the wires connecting each step of the process were a compromise in themselves. The standard speaker cable during the 80s was, much like today, made up of two multi-stranded copper wires of a smaller diameter (i.e. higher gauge / AWG). While this would serve to establish the basic connection for current to flow, the question was, if this presented the best possible solution. Madrigal went back to the drawing board and developed a speaker cable that was designed based on its sonic merits alone, leaving all other aspects aside and true to the Bauhaus motto: "Form follows function".

    By the 1980s, it was already known that solid-core wires offered greater musical homogeneity over all frequencies by limiting Eddy currents within the cable. It was also known that electrical current mostly ran along the outside of the wire. Madrigal’s aim therefore was to design speaker wire that was made of a single core and still offered the large surface of a thick and multi-strand wire. The result was a flat, ultra-pure, solid-core copper cable of 50mm in width per strand. In its original design, both one positive and one negative strand were stacked on top of each other, leading to an ultimate width of 100mm. Since this made the cable quite unmanageable in everyday usage, the Madrigal's original owner decided to separate the two strands.

    I decided to install the speaker cables on our main system. This consisted of our Restek V1 preamplifier with an H&S Exceptional amplifier driving our Martin Logan SL3 electrostatic loudspeakers. Our Sansui SR-525 turntable with AT-VM95 ML cartridge and Rega Planet 2000 CD player served as music sources. All units were interconnected by means of solid-core silver cables with copper-mesh shielding. I had recently written a review of the H&S Exceptional amplifier and was eager to find out, if the change of cables would lead me to a different impression of the amplifier. And, while I normally set up our system in bi-wiring with our Belden 9497 speaker cables connected to a single point of contact on the side of the amp, I used bridges with the Madrigal cables, half expecting that I would not be able to hear any improvement.

    I need not have worried. The Madrigal Mark Levinson solid-core copper cables turned out to be a game changer by any definition. OK, they were difficult to connect and to place behind our rack, and, yes, they looked pug-ugly with the wife-acceptance-factor (WAF) of a spaceship having parked in our garden, but these unique cables were able to drive our large Martin Logan speakers as if they were tiny headphones. José González’s album ‘Local Valley’ surrendered even the minutest details in the recording some of which I had yet been unfamiliar with, even from listening to the album with our AKG K712 headphones. The H&S Exceptional was a powerful amp that exerted lots of control in driving our Martin Logan speakers (also in terms of back-current decay), and these qualities worked very well in combination with the Madrigal cables.

    I found that the Madrigal Mark Levinson flat cables facilitated a tonally rich and highly musical presentation on our system. Although laden with recording details, their imaging remained focused, leaving lots of natural space around each tonal event. Homogeneity, order, and intimate vocal charm were their strong points. They helped to promote natural dynamics and were fully rhythmical and engaging throughout. It seemed that the Madrigal cables were capable of cutting the music free from any unnecessary constraints. Both the amplifier and the speakers disappeared from the music. Could these be the perfect speaker cables? Well, thus far, I have heard nothing better. Not by a long shot.

    Specifications

    • Design: solid-core
    • Material: ultra-pure copper
    • Termination(s): spade and banana
    • Length: 230 cm per channel
    • Width: 2x 50 mm per channel
    • Weight: 537g per channel
    • Country: USA
    • Year: 1988

    If you should have any further or different information concerning these speaker cables with regard to their original name, precise manufacturing date, and origin, please contact me at karsten@eiaudio.de


    Jörg Hegemann
  • H&S EXCEPTIONAL

    H&S EXCEPTIONAL

    1/17/2022

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Power Amplifiers

    The H&S Exceptional is an ultra-linear MOSFET power amplifier that is capable of pumping 200 watts per channel into 8 Ohm loads and double this amount into 4 Ohms. Usually, doubling the power-rating as impedance halves works in theory, but here it also does in practice. At the heart of the amplifier is a large toroidal transformer able to extract a maximum of 1000 VA from your household grid. The amp’s sturdy body is constructed out of 2 mm steel sheets, and an additional inner steel cage serves to protect the delicate audio signals from harmful EMF that are generated by the power section. The outer cover is chromed. This mirrored-surface helps to accentuate the amp’s modest size of just 36cm in width and 16.6 cm in height. When I first chanced upon it, I had been sitting in the same room for a while and had hardly noticed the amp in the rack. However, the modest first impression was quickly forgotten, when I carried the amp for the first time. Its body felt ultra-solid, as if the unit was cut from a single block of metal. This effect was supported by the use of high-quality materials, right down to the stainless steel screws that were perfectly integrated with the chassis.

    There was no popping, traceable vibration, or humming when the H&S Exceptional was switched on. Even with our periphery attached, there was no hissing or noise in the absence of signal. And, yes, even with my ear held to the speakers, the amp remained dead-silent. This did take me by surprise, because both our B&K ST-140 and Hafler XL280 amplifiers produced at least a faint amount of hissing, despite being well-made and excellent-sounding devices. My first impression therefore was that the H&S was an exceptionally well-behaved amplifier. Could this have been the reason for its ‘Exceptional’ name?

    The H&S brand was originally created by the German Ortofon service technician Eugen Stöckl and his partner, first as a side-project next to their jobs and then as their main occupation. Over a period spanning more than 20 years, H&S developed and built a range of small-series Hi-Fi components for audiophile listeners. Among these products were the phono preamp H&S ‘Exact’, the ‘Iceblue’ phono cartridge, and three consecutive versions of the amplifier that is presented here. The main difference between the amp versions rested in the designs of the housing with the heaviest specimen weighing up to 38kg. Through the increase in sales of their products to audiophile customers, H&S was beginning to get noticed. When, in 2011, the leading international Hi-Fi magazine “The Absolute Sound” listed the H&S Iceblue among the world’s best phono cartridges of all time, Eugen Stöckl was able to receive this considerable honour in person, before his untimely death from a heart attack in the following year.

    When reading about his sad demise on Markus Kannewischer’s website, I was reminded of the tragic fate of Peter Snell who had similarly died of a heart attack shortly after the launch of his popular C-Series loudspeakers. And, while men dying of heart failure was not unheard of, the idea of them dropping dead at the height of success did feel rather tragic to me. Hi-Fi had once again lost one of the industry’s humble contributors. Eugen Stöckl had been a staunch believer in the synergy of measuring and listening and spent lots of time doing both. His investment and stubborn diligence had paid off, and H&S was able to offer some true highlights to the audiophile community. The phono-preamp H&S Exact, for example, is considered to rank among the best of its kind until this day.

    As the H&S Exceptional was a heavy amplifier, it took some 30-40 minutes warming up before displaying its full potential. With the original cost of the amp having been well in the five digits, Mr. Stöckl could be certain that the original amp owners would neither mind nor notice the increase in their electric bill while waiting for their amps to reach operating temperature, especially, as they were anticipating to experience a musical performance that would make them feel as the amp’s name suggested.

    From one Solid State to another:

    I began my exploration of the H&S Exceptional by hooking it up to our main system. This consisted of our Restek V1 preamplifier (previously upgraded by Restek and featuring a quality power supply by Mr. Kassel) and Martin Logan SL3 electrostatic loudspeakers. A Sansui SR-525 turntable with AT-VM95 ML cartridge and a Rega Planet 2000 CD player served as music sources. All units were interconnected with solid-core silver cables with copper-mesh shielding. I had a choice of loudspeaker cables and decided to start with our trusty Belden 9497 in bi-wiring (and connected to a single point of contact on the side of the amp for improved response). I chose a range of music and styles to focus on various aspects of performance, but will use just a few examples to highlight my findings.

    Transitioning to the Exceptional from our trusty B&K ST-140 workhorse, I measured a 6 dB increase in effective volume when driving the H&S at the usual setting on the stepped Restek dial. I attributed this difference to the fact that the Exceptional had close to twice the power of our B&K but nearly the same input sensitivity. To avoid the criticism of comparing apples with pears, I made sure to set the volume at our usual listening level. Yet, even with the volume dialled back, the Exceptional sounded more focused and cleaner whilst playing stronger and more determined than our ST-140. In combination with our Martin Logan electrostatic speakers, the H&S achieved superb spatial and tonal separation of music events. The amp’s agile power output was driven by a total of 120,000 mF in supply capacitors which facilitated a rise speed of 300 V/μS. And, in combination with its formidable damping factor of 800:1, this resulted in an ultra-hard grip on the speakers. Amps like this are a valuable asset when listening to classical music and other scenarios in which many instruments play at once with multi-layered spatial and tonal character.

    The Exceptional was capable of superb bass-punch and ultra-abrupt decay while holding simmering high hats suspended for eternity. In an all-solid-state setup (CD, Restek, H&S) this much command could at times sound overly dry and tight-fisted, stressing accuracy over musicality, but even exchanging one part of this signal chain could result in magic. Switching from our Planet 2000 CD player to the Sansui turntable, for instance, highlighted the amp's more musical side. Vinyl could easily benefit from a highly accurate amplifier by receiving a bit more transparency, drive, and punch than usual. Due to the relative absence of overlapping frequencies, of the kind that came from time-lag issues on the part of the loudspeaker drivers, the H&S Exceptional would not on its own be deemed as a 'warm' and soulful amplifier. It is relatively free of such effects. But, when paired with a turntable and tube preamplifier, it could well contribute to a superb mixture of musicality and detail, in addition to offering the welcome flexibility of being able to drive even the most difficult loads.

    From exceptional amps to exceptional cables:

    On 19 January 2022, just two days after writing the previous chapters of this review, I exchanged our standard Belden 9497 speaker cables (which work excellent on tube amps, etc.) for a pair of monsterous Madrigal Mark Levinson flat solid-core copper cables. The result was truly magical with the H&S Exceptional amplifier sounding perfectly balanced. It seems that the increase in capacitance and the uniquely crafted solid-core design of the Madrigal cable served well to bring out the amp's true merits. After all, the H&S Exceptional was targeted at owners of Krell or Mark Levinson amplifiers who were seeking to move upward. More information on this subject can be found in my Madrigal cable review.

    Specifications

    • Power output (RMS, 8 ohms): 2 x 200 watts
    • Maximum power consumption: 1,000 watts
    • Transistor Type: Power MOSFET
    • Frequency response: 4 - 150,000 Hz
    • Total harmonic distortion: 0,03%
    • Signal to noise ratio: >100 dB
    • Channel separation: 105 dB
    • Input sensitivity: 1.3 Volts, max.
    • Input resistance: 27 kOhm
    • Damping factor: 800:1
    • Rise speed: 300 V/uS
    • Rise time: 0,5 uS
    • Dimensions: (W)360mm; (H)165 mm; (D)310 mm
    • Body: 2 mm steel casing + 2.2 mm steel shielding
    • Finish: polished chrome, silver-matt faceplate
    • Weight: 19,5 Kg
    • Years: 1990 - 2011 (Series 1-3)

    CrossXculture Business Language Training
  • HiFiMAN HE-400i

    HiFiMAN HE-400i

    1/14/2022

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Headphones

    The popular Chinese brand 'HiFiMAN' was founded by Fang Bian in New York. It evolved from an earlier company called 'Head-Direct' that had served as web-shop and Head-Fi sponsor. Among HiFiMAN's first products were the HE-5 planar headphones that were already launched in the founding year of 2007. Within a relatively short time, the new HiFiMAN brand became notorious for products offering excellent sound quality and advanced technology at affordable prices. Their widely successful HM-802, HE-560, and HE-400i headphones were released in 2014. Fang Bian’s design philosophy, as found on his HE-400i planar magnetic headphones, was loosely based on the much higher priced, and by then legendary, Stax electrostatic headphones. However, the planar magnetic principle never was in real-world competition with Stax in terms of sonic virtues.

    In an effort to bring down production costs, HiFiMAN set up two small factories in China and moved its headquarters to Tianjin in 2011. Early HiFiMAN headphones, such as the HE-5, featured wooden ear cups that had two virtues: They looked exquisite and helped the young company to keep tooling costs down. Although the use of wood served the company well in establishing its reputation as a producer of high-quality headphones, the material was prone to cracking as it aged and dried. Some of the early HiFiMAN customers sent in complaints of cracked wooden ear cups. Hence, the revised LE-version of the HE-5 featured ear cups made of plastic and already boasted some typical traits of the company’s signature planar magnetic headphones that were to follow.

    At 93 decibels sensitivity and low 35 Ohms impedance, the HE-400i headphones required only moderate amplification. In practical usage this meant that some listening pleasure could be derived, even when the headphones were connected to a smartphone or computer. This was in marked contrast to the company’s earlier planar magnetic headphones that required lots of clean power to operate, bearing some similarity to electrostatic drivers. Since affordable headphone amps with lots of power were still rare to find in those days, HiFiMAN also started to build their own dedicated headphone amplifiers, such as models EF-5 and HE-6, to power their fleet.

    I began my explorations of the HE-400i planar magnetic headphones driving them with our humble Douk Audio T-3 headphone amplifier, which we had only recently upgraded with General Electric JAN 5654W tubes and an ultra-linear power supply. The interconnects used in the listening test were made of solid-core silver with copper-mesh shielding and could be unforgiving of flaws in both the setup and choice of song material. I set out listening to José González’s album “Local Valley”, which offered a mixture of male vocals, lovely guitar picking, and some minimal and delicate sound effects, such as birds singing and the occasional synthesiser support. The album provided tonal balance as well as subtle bass lines in vocals and guitars. In doing so, “Local Valley” skilfully juxtaposed the close and imminent with the vast and distant to achieve an acoustically pleasing and highly entertaining effect.

    The HiFiMAN headphones had come to us packaged in a posh-looking black box clad with leatherette. In this box, the HE-400i were pressed so firmly and the cable rolled so tightly that I could not help but wonder if the box design would serve to protect its contents or rather damage the cable and ear cushions in the long run. I also noticed that the previous owner had lost or misplaced the additional 6.35 mm adaptor, because this was not enclosed it in the box. As the 3.5mm plug was angled, finding a replacement appeared to become a challenge. I put on the headphones, leaned back to listen, and immediately noticed that the original cable was too short for my sitting position. I could see how, at a mere 1.5m in length, the stiff and cloth-covered headphone cable could turn out to be too short for a whole range of applications. Replacement cables could be found online, of course. However, purchasing new cables of similar quality would drive up the price of these otherwise affordable headphones.

    I thought it best to compare the HiFiMAN HE-400i with our similarly priced AKG K712 Pro headphones. According to my research, the HE-400i had initially been sold for about 400.00 EUR in Germany and then dropped in price to 200.00 EUR, before they sold out in 2018/2019. Our AKG K712 Pro first entered the market at about 300.00 EUR in Germany and then dropped to just under 200.00 EUR, following the Christmas sale of 2021. As they were similar in price and completely different in terms of technology, they seemed to be worthy opponents to me. In order not to be biased by my existing listening habits, I made sure to listen to José González’s complete album on the HE-400i first. This would give Fang Bian's planar headphones and myself some time to adjust, as I could not be sure how long they had been sitting on the shelf, before I arrived at their owner's doorstep to free them from their fate.

    One of the first things I noticed was that the HE-400i planar magnetic headphones created a compact and focused image. The music seemed to be close and intimate, however, the impression was not so much of a lover whispering tender words in my ear; instead, it appeared slightly directive. The only exception to this being the birds on José González’s album, which seemed delicate and distant due to the recorded effects. There was a certain robustness to the presentation that took me by surprise and also some getting used to. And, although the ear cups were sealed with a tight metal grid that optically veiled the planar magnetic drivers underneath, the headphones provided little shielding from ambient noise. This made them ideal for critical listening in low-noise environments at home or in the studio. The fact that their music also radiated outward to considerable extent, as it did on most semi-open designs, could make them tricky to use in the monitoring of studio recordings.

    The HE-400i presented lots of drive and a tonally accurate midrange, with both male and female vocals sounding natural and full-bodied. There was, however, a limited sense of spacial separation between the singer’s voice and instruments in the room. Surprisingly for planar magnetic headphones, the HE-400i more resembled our Sennheiser HD 580 in this respect. In terms of spacial and tonal separation, the conventionally driven AKG K712 Pro were far superior. Perhaps I would have expected a little more agility from planar magnetic headphones, simply because of their low-mass foil design. While the midband was quite solid and seductive, the lack of agility also showed in the treble, which cut back earlier than on the AKG. The HE-400i started dropping off at 35,000 Hz, which was almost 5,000 Hz sooner than the AKG. And, while treble extension above 22,000 Hz is considered a ‘nice-to-have’ by those pointing out the limits of human hearing, this much difference in treble performance naturally affected the ability of the driver to fully generate the impression of space and dimension in the music. On the positive side, neither the AKG nor the HIFIMAN suffered from an unpleasant accentuation of frequencies.

    The HE-400i sounded less edgy when driven with sibilant music material, partly because they were less expressive in the high frequency range. They served well to highlight issues in the mid-band, where they were quite accurate. Bass performance was smooth and natural, showing a slight hump in the lower mid-bass that could have been caused by ear cup resonances interacting with the planar driver. This did contribute to a warmer and fuller sound and was not necessarily a negative aspect for music enjoyment, as it could be perceived as rather endearing. Bass roll-off was at 20 Hz, i.e., a full 10 Hz higher than on the AKG K712 Pro. While this was not a whole lot of difference, AKG did state in their sales material that the K712 Pro was designed with a +3dB increase in bass-extension. This served well to balance out the AKG’s spacious highs without being discernible as a bass-effect itself. The HE-400i seemed more compact in this discipline as well. On the whole, I found the HE-400i to be accurate and smooth-sounding headphones that lacked some refinement in terms of tonal and spacial presentation, especially in direct comparison with our highly engaging AKG K712 Pro headphones.

    I had originally embarked on my tour of exploration aiming to learn about the merits of planar magnetic designs as opposed to headphones with conventional drivers. The HE-400i showed me that decent sound performance can be achieved using both concepts. HiFiMAN was still a relatively new contender on the market whose biggest contribution to Hi-Fi was to make planar magnetic designs accessible to the average consumer. However, this did not mean that conventional driver concepts needed to fear being outclassed. AKG, Beyerdynamic, and other experienced headphone manufacturers, were perfectly capable of competing from a sonic perspective and still had the upper hand in some disciplines. For planar magnetic headphones to achieve the acoustic performance of the electrostatic designs of AKG and Stax, it would take far better drivers and amplifiers than we had available with the HE-400i headphones and our humble Douk Audio headphone amp.

    Specifications

    • Driver type: single-ended planar-magnetic
    • Design: over-ear, semi-open
    • Frequency range: 20 - 35,000 Hz
    • Nominal impedance: 35 Ohms
    • Sensitivity: 93 dB (1mWatt, 1.000 Hz)
    • Power rating: 200 mWatts, max.
    • Cables: cloth-covered, Y-shaped
    • Connector: detachable (mini-jack)
    • Cable length(s): 1.5m
    • Plugs: 3.5mm + 6.35 mm jack
    • Place of manufacture: China
    • Weight: 370g (without cable)
    • Year(s): 2013 - 2018

    80s night
  • Jörg Hegemann

    Jörg Hegemann

    11/28/2021

    Author: Karsten Hein

    Category: Interviews

    Tag: Musicians

    About the Interview

    Many years ago, I was asked to translate a CD booklet into English. It turned out that the CD was a new album by the Boogie Woogie pianist Jörg Hegemann, a music style that I had no personal connection to at the time. Over the years, I translated many of Jörg's CD booklets, but it was not until his release of "Foot Tappin' Boogie" that I could fully appreciate the genius of Jörg's music.

    "Foot Tappin' Boogie" is perhaps the first audiophile Boogie Woogie album ever recorded, because of two reasons: First, the Boogie Woogie was mostly famous in the 1930s and 40s, a time when the technology to create audiophile albums was not yet available. Second, audiophile recordings depend on so many factors that they are rare in any genre, including Boogie Woogie.

    What Jörg achieved thanks to the support of Klaus Genuit at Hansastudios Bonn with "Foot Tappin' Boogie" is so exceptional that I decided to invite him, to be my first guest on a series of interviews in eiaudio's "Music & Talk" section. I was a little shocked when he asked for the interview to be in German, but after spending a day-and-a-half on writing the subtitles for it, can say that I am happy with the result — even for international viewers.

    I thank Jörg for stopping by and for his consent to this interview. Hopefully, this will lead many people to the discovery of this album as an audiophile gem. Because — if there is one thing that audiophiles need — it is more variety in music. Too many of us are still listening to Pink Floyd's "The Dark Side of the Moon" album and believe that it all went downhill from there. — High time to wake up and smell the coffee.

    Purchase the album here and support the eiaudio-project, click here.

    Jörg Hegemann Interview

    Interview details

    • Recorded at eiaudio.de in Frankfurt Griesheim
    • Using 2x t.bone SC-1100 microphones
    • On a Zoom H4n Pro recorder
    • Date: 22 November 2021

    Digitising Records
  • Speaker-Audio Demos

    Speaker-Audio Demos

    8/26/2021

    Author: Karsten Hein

    Category: Explorations

    Tag: Speakers

    What should a loudspeaker sound like? — Well, if there is a short answer to this question, it is probably this: Ideally, a loudspeaker should sound like the original audio material that is being played back on it. Meaning, the recording of a rocket-launch should sound like the rocket being launched. And the recording of a saxophonist inhaling before playing the next tune should sound exactly like a human being taking a deep breath. A loud sound requires sturdy build quality and lots of air to be moved quickly, whereas a human being inhaling deeply requires the speaker’s ability to present the tiniest nuance.

    Acoustic instruments should be tonally correct with wood sounding like real wood, metal sounding like metal, glass like glass, etc. Voices should be as sweet, captivating, or even as raw as the singer’s own voice demands. Tonal correctness requires the speaker’s material resonance frequencies to be minimal and the moving mass of its drivers to be low. Natural instruments and vocals usually have at least two components: the sound that is deliberately produced and the ambient sound caused by the dimensions of the venue on the day of the recording. Both components should be presented equally well.

    The speaker’s frequency band should ideally be extensive, ranging from 20 Hz to 25kHz and beyond without significantly dropping in dB volume per watt. The ability to do so assures that sounds occurring along the fringes of the spectrum are fully presented. Even if some of these frequencies fall outside of human hearing, they do affect the audible frequency band through layering and overlapping. Maximum realism can only be achieved, if no aspect of the original signal is omitted.

    Much has been written on the linearity of loudspeakers. This refers to the ability to play all frequencies at equal volume. When performing in a home or studio environment, however, the linearity measured and certified in a laboratory has very little to do with the acoustic reality of a private listening room. This is why loudspeaker manufacturers take an educated guess regarding your household or studio furnishings and will accentuate frequencies that they estimate will be absorbed by your furniture and dampen those that will be enforced by your walls and ceiling.

    The result of all this is that ‘speaker sound’ exists, even if loudspeakers are usually sold on the premises of being linear. But can this be shown, recorded, and archived for posterity? Well, at this point I am neither sure it is possible nor that the data produced in a recording of a loudspeaker has any value for the decision making process of which speaker to buy. But, since our project is called ‘Explorations in Audio’, I am willing to ‘explore’ the possibility. You see, explorers are naturally attracted to the unknown, especially, if they are greeted with lots of scepticism.

    In this new series of explorations I am sharing with you how a given loudspeaker performed on the day of the recording in one of our listening rooms, using the recording equipment available to me at the time. The material is then uploaded to a streaming platform to be played back on any random equipment that you might have at hand: anything ranging from the built-in speaker of your mobile phone to your own High-End stereo system. The listening result is then up to you to interpret. I would be interested in reading about your findings during playback in the comments section below or under the YouTube file. — Enjoy :-)

    Standard Audio Source (Type 1):

    • CD-Player: Marantz CD-17
    • DAC: Cambridge DacMagic 100
    • Preamp: Dynaco PAS-4
    • Amplifier: Hafler XL-280

    Standard Recording Equipment:

    • Microphones: the t.bone SC1100 (x2)
    • Recorder: Zoom H4n Pro
    • Mastering: Apple iMovie

    Standard Measuring distances:

    • Microphone to speakers: 200cm
    • Music volume: 75dB (peak average at 200cm)
    • Between microphones: 40cm
    • Distance from ground: 100cm
    • Recorder input sensitivity: 80

    Dahlquist DQ10

    Tannoy XT8t

    Snell Type C IV

    ATD Pata Acustica (Auditorium 23)

    Martin Logan SL3

    TEAC LS-H255-MA

    Original CD Audio