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.

  • Sennheiser HD 580 Precision

    Sennheiser HD 580 Precision


    Author: Karsten Hein

    Category: Gear & Review

    Tag: Headphones

    In my recent article on the Beyerdynamic DT 990 PRO, I wrote that my reason for purchasing new headphones had been that I could not remember who I had given my old Sennheisers to. Some weeks later, I found them at my parents’s house, next to an unused field recorder. As it turned out, the Sennheisers were much older than I remembered (and had professed in my article). A faded and wrinkled receipt showed that I had bought them at Galeria Kaufhof in 1996. All the more, I was surprised to find them still in good shape, even after 25 years. And something else surprised me: Even before listening to them again, I still had a solid memory of their sound.

    Before purchasing my Sennheiser HD 580s, I had listened to music with a set of closed Panasonic studio monitors that we had bought in New York during the 1980s for the pretty steep price of 250.00 USD. I remember that they had impressive bass and were able to lift the ear-pieces off your head. They also featured an otherwise decent sound. I carried them around until the cushions disintegrated and their black and flaky residue would be clinging to my hair for the rest of the day. At the time, I was reluctant to give them up. And switching to the open Sennheiser HD 580 seemed to be a sonic step back. Everything I had loved about the Panasonic headphones was gone. Instead, there was this baren new clarity, a quality that I had trouble warming up to at the time.

    Perhaps this was partly due to the fact that the relatively high impedance of 300 Ohms made them more difficult to drive with the equipment I owned in the 90s. It seems that these headphones were directed at the professional market, where high impedance is less of a problem. And, since the Pioneer had been of closed design, the semi-open Sennheisers seemed far less punchy in bass. This made me miss the familiar fullness of the lower frequencies. However, dusting them off and listening to them again after so many years, with years of discerning speaker auditions having passed on my side, my taste in sound and music had also matured, and the Sennheisers left a much more balanced impression than they used to. I was able to see the advantages of such an open design. It all depended on the application.

    On professional recording equipment, such as our Zoom H4n, the HD 580 did do quite a wonderful job in depicting voices and stage dimensions. I noticed this first when I played back a recording of my father playing the guitar. Both the guitar and my father sounded so realistic that I had to look up from the monitor to check, if he had started playing again. I was amazed to find him sitting with his hands by his side, patiently waiting for me to finish my listening check. A simmilar effect happened, when I was listening to my recording of Luigi’s Snell C-IV loudspeakers playing the first song of Jörg Hegemann’s “Foot Tappin’ Boogie” album. I had set up two large-diaphragm studio mics, pressed record and then walked across the room to turn on the CD player. Listening to this again during video production a few days later, I repeatedly looked up, fully convinced that someone was approaching me from behind. The impression was fabulously real.

    When it came to voices, the Sennheiser HD 580 deserved the name ‘precision’. Tonal accuracy would have been an even better name. And this character trait did not depend so much on the equipment driving them, either. On the other hand, they were not particularly strong in terms of bass extension. For optimum bass, they required a strong dedicated headphone amp. On our T-3 Plus with GE tubes, the HD 580 showed a punchy mid-bass, but lower bass frequencies were still under-represented to the extent that it took some getting used to. At the higher end of the spectrum, the Sennheisers tended to focus on the essence only. Sadly, this meant losing some of the nuances and subtle transients of the music. This made them excellent companions for smaller recording studios to monitor the tonal balance of voices and guitars but also rather useless for genuine audiophile listening, which was perhaps not surprising given their relatively low price point.

    As I found out when doing research on the specifications, there is a real HD 580 fan community out there. And, to my delight, I even managed to find a new replacement head-cushion for my Sennheisers online (not yet shown on the photos). They were well-worth keeping, if only for monitoring future studio sessions with our Zoom recorder. In this scenario, I could not imagine anything more useful.

    Company History

    Fritz Sennheiser set up operations in a farm house near Hanover in 1945 post-war Germany. His young start-up Laboratorium Wennebostel, or ‘Lab W’, soon became a supplier of measuring equipment to Siemens. In 1958, the company changed its name to Sennheiser electronic. Although Sennheiser’s MD 1 mic still borrowed heavily from existing microphone designs, the MD 2 mic was of the company’s own engineering. Other microphones soon followed, with the first Sennheiser wireless microphone system reaching the market in 1957. In 1960, the company introduced its famous MD 421 microphone, which is still available in stores today.

    The company produced a range of successful products and soon expanded to form subsidiaries in over 20 countries. Famous headphones include the HD 25 (1988), the Orpheus electrostatic headphones (1991), the HD 800 high-end headphones (2009), and the electrostatic Orpheus successor HE 1 (2015). Both the Orpheus and the HD 800 are considered to be top of their range products. At the time of writing this article, the company is run by the Sennheiser family in its 3rd generation.


    • Driver type: single, dynamic
    • Design: over-ear, semi-open
    • Frequency range: 16 - 30,000 Hz (-3 dB)
    • Impedance: 300 Ohms
    • Sensitivity: 97 dB (1,000 Hz)
    • Harmonic distortion: < 0.1 dB
    • Plugs: 3.5mm + 6.3mm jack
    • Weight: 260 grams
    • Place of manufacture: Ireland
    • Cable length: 3m
    • Year(s): 1993 - 1997

    Jörg Hegemann
  • Beyerdynamic DT 990 PRO

    Beyerdynamic DT 990 PRO


    Author: Karsten Hein

    Category: Gear & Review

    Tag: Headphones

    When my friend Charles asked me to digitise his record collection for him — the remaining pieces he had salvaged from the flooding in his basement — I needed a pair of headphones to oversee the process with. My last use of headphones had been so long ago that I could not remember who I had lent my Sennheiser HD580s to. Nor could I be sure that they still existed, considering they were from 2008.

    I contacted Jens, who is a composer and producer of music himself and usually quite knowledgeable about what is available on the professional studio market, to ask him for advice concerning reasonable headphones for my task. He mentioned that he was quite happy with his AKG K271 MK2 headphones. Jens referred to them as being “honest and revealing”. If I wanted even more honesty, he suggested, I might also consider the open K702. I thanked him for his prompt and knowledgeable support and bought the Beyerdynamic DT 990 PRO instead.

    Do you have such moments, in which you know that you are getting excellent advice and then end up doing the exact opposite? In retrospect, I think it was the AKG headphone’s bulky look that put me off purchasing them. The two solid steel rods connecting the two ear pieces that remained fixed while only the head strap was lowered. This part was designed so much more elegantly on the Beyerdynamics and made me blind to some obvious disadvantages that should have got me thinking, especially with my prior knowledge in audiophile matters.

    For one thing, the Beyerdynamic DT 990 PRO only had one single, non-detachable signal cord. A single cord had some disadvantages, when it came to signal integrity, because the two channels ran in very close proximity to each other over a longer distance. This could potentially cause inductivity that negatively affected the signal. The cable being curled like an old telephone cord only contributed to this phenomenon. In HiFi, cables touching cables was generally not a good idea and to be avoided.

    I also could not help but wonder, if the two channels had cables of the exact same length, as one of them needed to be run over to the other side of the headphone to reach the other driver. The relatively poor center image of the 990 PRO, especially in comparison with the T1 of the same company, made me doubt that this was the case. One could argue that this should not have mattered on a short cable run such as this. But, if this was the case, why did Beyerdynamic not simply use the same cable design on their flagship T1 headphones? The answer is simply: Because in HiFi everything matters.

    The fact that the cable was not detachable could be seen in two ways: On the positive side, a soldered connection did not inject as much mass into the signal path as a plug would have done. But on the negative side, it meant that I was stuck with the cable it came with, even though I did not like it much. No upgrade was possible in this case, unless I was prepared to take out my soldering iron and get busy soldering new connections.

    The DT 990 PRO were of light weight and did not press too firmly on the temples. I could see that wearing them for many hours would not present a problem. I did find that they could get warm with time and would not recommend them in areas of high humidity or temperature. However, all this I could have easily lived with, if they had offered greater tonal balance. This was the most obvious weak point of the DT 990 PRO headphones and made them rather undesirable for audiophile listeners. It was sometimes said that they were non-linear or ‘HiFi’-sounding — whatever that meant — but I do feel this to be an understatement.

    Some frequencies of the mid-band strangely seemed suppressed, either by the driver or cabinet design, or by the thick acoustic foam-padding over the drivers, as to make voices sound thinner and sharper. I tested this with three different kinds of output: my computer sound card (only when digitizing records), our Denon CD player’s internal headphone amp (for comparison), and our Douk Audio T-3 Plus tube headphone amp (during an audition). The loss in frequencies remained similar, and this, although the treble was the harshest on our T-3. Since the latter had no difficulties driving high-resistance headphones and worked very well with the Beyerdynamic T1, I assumed that the effect of a recessed mid-band was built into the headphones themselves.

    Given my narrow range of amplifier equipment, it was well possible that the DT 990 PRO would have performed better in combination with other devices. However, especially having the T1 as benchmark, I find it hard to believe that any differences in source design could paste over the general tendency of the DT 990 PRO to sound unbalanced, especially on vocals.


    • Driver Type:  single, dynamic
    • Design:  over-ear, open
    • Frequency range:  5 - 35.000 Hz
    • Nominal impedance:  250 Ohms
    • Sensitivity:  96 dB (1 mWatt, 500 Hz)
    • Harmonic distortion:  0,2% (1 mWatt, 500 Hz)
    • Power rating:  100 mWatts, max.
    • Cable:  Single (spiralled), fixed
    • Plugs: 3.5mm + 6.3mm jack
    • Place of manufacture:  Germany
    • Year:  2021

    CrossXculture Business Language Training
  • Jörg Hegemann

    Jörg Hegemann


    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

    80s night
  • Beyerdynamic T1

    Beyerdynamic T1


    Author: Karsten Hein

    Category: Gear & Review

    Tag: Headphones

    Following my recent exploration of the affordable T-3 Plus headphone amp by the Chinese brand Douk Audio, I was left wondering how good this little amp actually was. At the time of my test, I was lacking a pair of headphones that would be revealing and balanced enough to allow me a definite verdict from an audiophile perspective. Dissatisfied with the open ending of my exploration, I kept pondering on how to proceed, until I remembered that my friend Michael owned a pair of top-of-the-line T1 headphones from the German manufacturer Beyerdynamic. I invited Michael over to our house and asked him to bring his headphones along. That evening, we set up a test to examine the merits of both: his headphones and Douk Audio’s T-3 Plus preamplifier.

    As reference, we used Luigi’s Pata Acustica speakers driven by our Hafler XL-280 power amplifier and our Dynaco PAS-4 tube preamplifier. The latter had its focus on vinyl and a great phono stage. The signal source on this system was a Technics SL1310 turntable with AT-VM 540 ML cartridge. I knew this system to offer excellent tonal balance and dynamics while being revealing enough to be highly engaging. If there was room for criticism at all, this would be in respect to bass extension. The Pata Acustica bookshelf speakers had a natural limit when it came to bass that I generally did not mind but some hard-core bass-lovers might object to.

    The test system consisted of our Philips GA212 turntable with Shure M 75 ED cartridge, connected via Fast Audio cables to Douk Audio’s T-3 Plus preamplifier. This had its noise-free energy coming from a new and dedicated linear power supply. By that time, I had already decided that I preferred the Douk’s phono stage abilities to those of its line input. I have not checked, but it is well possible that the line stage is passive on the T-3. On the evening of our test, we focused on three songs on vinyl: Seasick Steve’s minimalist “Hard Knocks” representing male vocals, Helge Lien Trio’s jazzy “Gorogoro”, and Katie Melua’s relentlessly swelling vocals on “Heading Home”. We started with Seasick Steve on the Pata speakers, then moved on to the T-3 Plus with my own Beyerdynamic DT 990 PRO headphones for comparison. Finally, we connected the Beyerdynamic T1. We paused to compare our findings following each step, and although we did not agree in all aspects, our basic assessments turned out to be the same.

    The male singer's voice sounded tonally most accurate via the Pata Acustica loudspeakers and very similar to this via the Beyerdynamic T1 headphones. While the loudspeakers set a wider and highly accurate stage and sounded a little fuller, the T1 sounded more intimate and reached a little lower in bass. Slightly more detail was audible on the loudspeakers, with individual notes trailing longer. However, this was mostly due to our new Audio Technica cartridge, the particular cut of its ML stylus, and the greater ability of the Technics turntable. Our own Beyerdynamic DT 990 PRO headphones, in comparison, revealed a midrange dip and did not manage to hold the music together as well as the other two contenders. This made bass sound more boomy and treble more pronounced. Additionally, it seemed as if there was a cloak over some frequencies, an over-dampening of the headphone shells, perhaps. Individual high-notes, especially, were flung deeply and seemingly detached into the cloak of darkness that otherwise prevailed. Interesting, but somehow not useful for voices and acoustic guitars.

    On Helge Lien’s Jazz piece, we began with our reference speakers that gave a formidable impression of the event. We then went on to audition the DT 990 PRO first. Our reasoning for changing the original order was that we did not want to fall into the trap of fulfilling our expectations. Without vocals present, the DT 990 PRO sounded natural and exciting, lacking some of the fullness of the instruments on the Pata speakers. While the rendition was engaging and entertaining, careful listeners could notice a lack of substance. The Beyerdynamic T1 brought substance back and held the performance together. Here, the stage seemed wider, and locating instruments on stage was easier, although the speakers prevailed in the latter aspect. There was sufficient musical detail in all three contenders, but the T1 and the Pata's sounded most accomplished.

    We completed our test with Katie Melua’s “Heading Home”. The recording showed a slight metallic ringing to Katie’s microphone that might have added an interesting effect on a car stereo but seemed rather misplaced in audiophile listening. Therefore, any character trait during reproduction that highlighted this effect was unwelcome. Not surprisingly, the revealing nature of the Audio Technica cartridge brought out the metallic quality of the recording. The Pata handled this rather well by tonally integrating the effect without letting it break away. This did keep the listener engaged, if only to wonder when the treble would lose control of the moment. The DT 990 PRO brought about a more unfamiliar Katie Melua, accentuating some of the rougher aspects of her voice. Katie seemed more rocky, more like a younger Pat Benatar. I enjoyed listening to this rendition of her voice, until I started longing to have the familiar Katie back. The DT 990 PRO's suppressing of selected frequencies did not come without risk, of course. On the other hand, the T1 managed Katies voice very well, partly because they did not have to struggle with input coming from an over-sensitive ML stylus. The Shure’s elliptical diamond did not add any sibilance (as it sometimes did). Consequently, the performance seemed clear and solid, although not quite as suspenseful as on the Pata system.

    Beyerdynamic’s T1s are tonally accurate sounding headphones with a solid sound stage that present the music performance as a homogenous whole. The excellent materials used pay off in creating a pleasant and entertaining musical experience. These headphones deserve a good amp that can deal with high capacitance output of 300-700 Ohms. To both our surprise, the small Chinese T-3 held its own during our test, if only after upgrading, tubes, power supply, and interconnects to an audiophile level. Following these significant upgrades, I can recommend both, even in this combination.

    Company History:

    Beyerdynamic has a long history in audio electronics. The ‘Elektrotechnische Fabrik Eugen Beyer’, as the company was first called, had its origins in Berlin, Germany, during the 1920s. Its first products were loudspeakers for use in the emerging film palaces. Beyer's first pair of dynamic headphones, model DT 48, followed in the 1930s. With Berlin having been severely bombed during World War II, many German companies left the city ruins to seek new opportunities elsewhere. Eugen Beyer finally found a new home for his operations in Heilbronn, a German city located about 600km south-west of Berlin.

    Famous Beyerdynamic products where the DT 49 (1950s) hand-held headphone, used in record shops and popular record bars, the M 160 ribbon mic (1957), and the E-1000 microphone (1965). At the time of writing this, Beyerdynamic is still based in Heilbronn and operates an American subsidiary Beyerdynamic, Inc. in Farmingdale, NY. The company offers a range of products, ranging from headphones and microphones of conferencing and interpretation equipment.


    • Driver Type: single, front-angled, dynamic
    • Design: over-ear, semi-open
    • Frequency range: 5 - 50.000 Hz
    • Nominal impedance: 560 Ohms
    • Sensitivity: 102 dB (1 mWatt, 500 Hz)
    • Harmonic distortion: 0,05% (1 mWatt, 500 Hz)
    • Power rating: 300 mWatts, max.
    • Maximum output: 126 dB (300 mWatts, 500 Hz)
    • Cables: 2x cloth-covered OCC 7N copper
    • Plugs: 3.5mm + 6.3mm jack / XLR, mic jack (optional)
    • Weight: 356g / 437g with cable
    • Place of manufacture: Germany
    • Year: 2016, 2. generation

    Digitising Records
  • Speaker-Audio Demos

    Speaker-Audio Demos


    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)

    Original CD Audio