I was very excited about Dan Clark Audio's Stealth but when I tested the Expanse I wasn't sure which of the two I preferred. Here’s Christoph Stickel's opinion on the subject:
DS: I see you have both Dan Clark models in use. I had also tested them once and always found it very difficult to say which one is my real favourite. What do you think?
CS: Carsten had already given me the Stealth right after the High End show. I was very enthusiastic about it. Now I've got the Expanse. I haven't wanted to put it off for a long time. One reason certainly is that the ears don't get so warm when listening over a long period of time. It simply is an open system. The wearing comfort is different because air gets to the ears and you don't get sweaty even when listening for a long period. After carrying out a longer A/B comparison with the Stealth, it's not just a matter of ventilation: the Expanse seems a bit more mellow to me. It is more pleasant. It renders everything identically as I know it from the Stealth, just a little more friendly. Listening never becomes an effort. Recently I've had both of them here for comparison and I've noticed that I'm listening more through the Stealth again because it renders the upper mid-range very clearly, for me this being the frequency range between 1200 and perhaps 3000 hertz. I am able to really hear every subtlety here. I also hear more punch and more definition. Not that the Expanse has less of that, but it handles it more kindly. That could be due to the closed system, you'd have to go and ask a headphone designer. I can't answer that. But the Stealth is more fun and makes more sense for my professional situation. With the open-back Expanse, I just listened to records, just enjoyed them, simply forgot to work: "This is terrific! Isn't the world a beautiful place?" But the Stealth prompts me to "Do something now". Here’s another task, that needs to be done. And when I have finished it, the Stealth also says, all is good now and is pure enjoyment. I don't want to give both a rating. I would just describe them as different. Whereas both create the same sense of taste, I don't know how you think about it: For me, it's the same grape variety, the same winemaker, but the wine is vinified differently. That's how I perceived it.
DS: Absolutely, I also find it very difficult to choose one side, but in the end I tend towards the Stealth.
CS: You also make recordings. Then it's very natural that you like to have this immediacy and proximity and unambiguousness for your sound engineer's job. In addition, you can listen with the Stealth in a focused way even in a noisy environment.

Sebastian Müller kindly provided us with excerpts from three tracks of his first album S/M/B 1 for this article. Read how the mixes were edited, which you can compare with the final versions via download:
DS: It's nice to talk about mastering. But you said you would give us examples of what mastering is about. What can you demonstrate?
CS: Basically, it is absolutely lovely of Sebastian Müller that he makes his band’s material available to us and that we are allowed to perform an A/B comparison. It's not at all a matter of course to get permission from a record label, from a producer, to use recordings. We will pick two or three tracks from the two albums that I mastered for Sebastian Müller and compare them. One is the original mix as I received it and the other is the mastered version. This isn’t a classical genre, nothing purist. It’s an awesome band, soulful, partly danceable, it has got inspiring singers, and a terrific brass and rhythm section. Not to forget the exquisite compositions by Sebastian. In other words, this has to work on a commercial level.
I had done my sound editing here exclusively on the analogue level. I received the mix as digital files, then converted them digital-to-analogue and subsequently worked with analogue equalizers, compressors and so on. Then I converted it back analogue-to-digital and created the digital files for release. For mastering, there were parametric EQs, and an analogue dynamic EQ. In addition, there was a tube compressor, but here it has more of a "glueing" effect, basically bringing all the material together, forming even more of a band out of the individual signals, whereby the control response is relatively gentle. It’s about a decibel or so, this compressor also brings a little bit of the tube's harmonics into play, confering it a little more character. Then, as aforesaid, there's the parametric EQ, which I used to take out a few resonances and feature the lows a bit more, where I felt it was right. On top of it I added a compressor, which basically resolves the transients a bit clearer and condenses the mix. For the SMP band, I used the Vertigo VSC-2 as a compressor, which can handle this very nicely and with which I can exactly map out this swing-in and swing-out process even clearer, so that the groove, the soul, the intensity that is on the recording is emphasized even more strongly.
DS: Why isn't all this already done in the mixing?
CS: Recording and mixing is a process of working on the music, interpretation, performance, the sound of instruments and much more, and then putting it all together - a process that can take days or weeks. I master about four albums in a week, so I have a very good overview of how albums of a genre sound, how the mixes sound. I look at the production from a distance. For example, I haven't spent nights with the singer tweaking his or hers intonation or trying to finance the production. So I am unconsumed and unbiased and can concentrate exclusively on the final product, having a lot of experience in evaluating things as well. After I've worked out the mastering, it gets of course back to the artist, or in this case the producer, who listens to it all the way through and hopefully says: "It's wonderful" or "Christoph, that one track, can you get it a bit more aggressive?". Feedback that I then incorporate until everyone is happy. Then I still have to bring it into the right shape: Transitions, pauses, volume – those things we already talked about. And then I work out the different masters for the different media applications. All of this resumes to about one and a half days of concentrated work, which can sometimes be spread over a week. But I always try to work out the whole sound for an album in one session, getting an idea, crossing the gap. Possible corrections and the creation of the master can then also happen later.

Downloads for different music portals and physical sound media require different versions. Here Christoph Stickel names some of the special requirements:
DS: When you say you're finishing an album for the different media, that doesn't mean that anything else is changed tonally, does it?
CS: If it's for vinyl, then I have to pay close attention. In principle, I create a version for myself that I feel is harmonious, that sounds to me exactly the way it should be. If it is intended for vinyl release, for example, there are certain restrictions: In the low frequency range, for example, we have to be mono-compatible. I examine the lows for mono compatibility for vinyl and if necessary I correct them so that it sounds good, so that it doesn't just match technically. I make sure that the cutting engineer who does the transfer from my master to the cutting stylus receives material that he can work with well, that presents, for example, no phase problems in the bass. The treble must not be too intrusive, so that he can easily find the perfect solution for his equipment. The cutting engineer may also have to do some reworking. But I try to prepare the master in such a way that even after the technical adjustments for vinyl have been made it sounds as I had imagined it. For some music genres, my vinyl version is also a bit more dynamic than the one used for digital releases.
In addition to vinyl, there is also the "Apple digital master", for example, which has to be delivered and checked in a certain form. In addition, for the majority of online media we have a standard of -14 LUFs or -16 LUFS ("loudness units relative to digital full scale (0 dBFS)"). This is a standardized loudness measurement, which I don't want to go into it technically now. The important thing is that it works properly on the online media. That it complies with the standards but does not fall behind other tracks on a playlist.
DS: There really is no getting around making the lows mono for vinyl?
CS: Of course, the bass doesn’t necessarily have to be mono, but the left and right channels must correlate with each other. There may well be different information on the left and right, but it must not eliminate one another when switched to mono. Such signals cannot be cut on a lacquer foil. So it’s not mandatory for me to make it mono. But if I have the same information on both the left and the right, which then becomes increasingly wider in phase, the cutting stylus would try to follow up with a movement, that is physically impossible. In that case, I have to set the bass to mono so that nothing can go wrong.
DS: That's why you have your display instruments.
CS: Instruments help well here, but you should also follow your ears. The same applies for the high frequencies. We should avoid to have too much of a treble boost, because due to the RIAA equalization we always have to face a technically conditioned treble boost on the record when it is cut. And, if there is a decent sharpness in the highs, for example, at twelve kilohertz, as well as notable sibilants and blaring cymbals, then the cutting stylus will reply: "Oh no, not this way“. That's when I have to try to get things a little smoother beforehand. But, I'm not trying to interfere with the cutting engineer and do his job. I can't do that at all, because I have neither his knowledge nor his equipment. But I have to prepare it aesthetically in such a way that possible technical intrusions do not change the tonal idea significantly. If the cutting engineer now has to apply a few technical adjustments, the sound will be just right. From this point of view, I can evaluate the high frequencies very well using headphones.
DS: On a nasty note, I wouldn't dare to do that with an Audeze, for example, because I've seen what good equalization looks like done by Weiss for the LCD-X. We’re talking about plus/minus four decibels here.
CS: Once you're tuned in to something, that usually helps. But when it comes to mastering, when I raise or lower a particular frequency, I am handling steps of 0.25 decibels. Then such a lack of cleanliness on the part of the monitors or headphones is critical. If I make settings that sum up to three or four decibels, then I start to think if I'm fooling around or what’s the problem at all. These are ranges that are simply too large. Look at the settings here: I have 0.5 decibels, I have one decibel. So between 0.5 and two decibels is the normal range I am working in. That means that the playback should also be a clean one within this range.

So, enough of theory here: Enjoy excerpts of three tracks from Sebastian Müller's first album and compare them with the mix that was delivered for mastering. Have fun with it!

Download. Sebastian Müller Band 1

In einem kuehlen Grunde Mix In einem kuehlen Grunde mastered Samballi Mix Samballi mastered Scarborough Fair Mix Scarborough Fair-mastered

PS: Time and again we are asked whether the music files can only be listened to on the computer or whether they can also be saved on one's own hard drive. Of course, the latter is possible as well. First off, here come in brief operation instructions for Mac users: Perform a so-called secondary click, depending on the trackpad settings, by tapping with one finger on the bottom right of the trackpad or at any point by tapping with two fingers. With the Magic Mouse, you can perform the secondary click by pressing on the right (default setting) or left surface of the mouse. A selection window then appears in which you click on "Load linked file" or "Load linked file as" to start the immediate download of the desired file. For the Windows users out there, Wolfgang Kemper explains how to do it: Click on the download symbol with the right mouse button and select "Save as...". Then a window appears in which you can select the location where you want to save the file. Click on the "Save" button and you are ready to go.