Interview of Lars Torressen

IWA: What are the qualities of the sound that you value most? The ones that you're after in building up a system?

LT: Dynamics and timbre, like I hear it from real instruments.

That also means great downward dynamic range, the ability to render very low level sounds along with strong sounds. Some call this resolution. This is what I like about the sound from single end DHT tube amplifiers.

I started this hobby in the eighties when The Absolute Sound -magazine was ruling, telling people a good system had to render spatial information well. That meant great depth and width of soundstage with the soundfield spread out behind the loudspeakers, the speakers should “disappear”, or in other words the system should transport you in space and time to the original event. There was also much talking about the frequency extremes, reflecting the way in which loudspeakers were constructed and sold, just look at some ads from the eighties. The middle tone was somehow forgotten! What this lead to was a sound without drama, without colors not able to communicate the nerve in the music.

I must admit that I also was soaked in this HIFI -ish approach to music reproduction, but got bored by the lack of crucial qualities like dynamics and timbre, I just couldn’t hear that from typical HiFi systems. Even the Quad ESL and OTL -system I had at the time, which was very good at 3D and low distortion, bored me.

IWA: What, in your mind, are the main attributes of the sound that are not obtainable through a conventional commercial system?

LT: Again I have to say dynamics and timbre, but have to add flexibility and well behaved room interaction in order to be accurate. If you by a conventional commercial system mean a high power amp, followed by passive filters and low to middle efficient two way polypropylene small size box speakers topped by the ubiquitous 1” dome tweeter, this route which is followed by, lets say  99 percent of the manufacturers, leaves you with a lot of serious shortcuts in these areas.

The bass loudspeaker will very likely be bass reflex or infinite baffle loaded and consequently disturb the neighbors, pressure loading your room and surely create standing waves. The small dome tweeter will struggle to cope with the transients and sound flat. In addition the amplifier has to handle the whole bandwidth creating its own problems.

The system I have now overcome these shortcomings by making a better interface between the amplifier and the loudspeaker, it’s directly coupled. The compression issue is dealt with by using high efficiency loudspeakers that can go extremely loud if needed. In fact the horns are 110 dB/m at one Watt.

Good sound reproduction is basically only available through some effort by the user and intelligent use of quite expensive technical solutions, for instance tubes and transformers. Which implies that when voltage gets up so do the parts price. These technical solutions become very expensive when applied in a commercial system but is within reach of every DIY’er.

IWA: If you anyhow had to buy a system from a shop, what would you choose (a hypothetical commercial system)?

LT: I have heard some very good commercial systems with either Avantgarde horn loudspeakers or the Audionote Japan Ongaku 211 SE amp which is definitely not conventional or obtainable for most of us. I think I would build a system around one of these products.

IWA: The pros and cons of relying on a horn based system?

LT: Pros: first of all high efficiency, that means you can make use of single end topology for the power amp, and the many wonderful low power tubes out there, 801, 2A3, 6L6, 807, 300B and a lot of unknown transmitter tubes. Second, low distortion gives wonderful reproduction of voice and woodwinds for instance. Third, controlled dispersion, which is inherent to the horn principle means less room interaction. I like to consider my system as large ear speakers, the instruments are very present. I like that, some people don’t.

The soundstage is somehow in front of the speakers, I use to say I want the musicians in MY room, it´s quite psychedelic and I just love it!

Cons, then. It takes time and patience to achieve the best sound horns can give you. There are lots of pitfalls and only recently the audio world have understood how good horns can actually sound. Real horns are big too. Horns present the soundstage in a different way from conventional speakers, more upfront, if this is a problem for you it’s obviously a con.

IWA: Should one have more than one system depending on the type of music, or can there be a universal one?

LT: Yes, not only because of the type of music, electronic versus acoustic but also because of the recordings, mono versus stereo.

Optimizing a mono system is one of my favorite projects that is going on in my workshop. Besides my mono collection of jazz and classical music I have a small collection of jazz on 78 rpm. The sound of these records played at the right EQ is truly remarkable, so dynamic, so groovy that they deserve a second system. Regarding playback of acoustical versus electric music I think my horns are good at both, but there exist better loudspeakers for baroque music if one is obsessed at getting the soundstage right.

IWA: How to overcome the fact that active filtering will add extra components on the signal path (in the case of digital, extra conversions)?

LT: There is an enormous potential for good sound in the amp/loudspeaker interface and in the loudspeaker/room interface. The system always has to be considered as a whole and it’s a give and take situation. In my experience, being able to control these interfaces gives me the best sound overall. At first sight my system has grown quite complex but remember that the crossovers are moved forward in the chain, standing between pre- and power amps. I think they do less harm to the sound there, even being digital. What I gain sound wise using carefully optimized horns directly driven by the most transparent power amps there is, totally overshadows the flaws of extra AD/DA conversion in the digital filter. Having control over phase alignment and room interface also adds to this.

Active filtering either analogue or digital gives you the opportunity to use a dedicated bass amplifier, which has an enormous effect on the dynamics and the stability of the stereo image. It’s then easy to avoid the collapse of the soundstage with crescendos. That is a hallmark of a  typical commercial system.

IWA: Say something wise about the tube vs. transistors issue? In your experience, the main faults of transistor amps?

LT: I thought I had made up my mind about that but that was before I heard a really good transistor amplifier, a big Bryston that had total control in the bass and also sounded good in the upper octaves. I haven’t compared this directly to a single end tube amp, and see no reason why I should, they are too different beasts.

In my experience transistors are for power and bass control, tubes are for delicacy and resolution in the middle and upper register. That’s one of the reasons why I make use of the bi-amplify principle, to get the best from both worlds.

I feel the main fault of a typical transistor amp, take for instance my Hiraga 8W, is lack of resolution and downward dynamic range, this is based on direct comparison so I know that. Why, I don’t know but maybe a transistor push-pull amp is too complicated technically? Maybe the power supply is flawed? A lot of what we hear from a system is depending on circuit solutions, the technical solutions. To loosely quote Tim de Paravicini “I can make a transistor amplifier sound like a tube amplifier”, it´s probably a matter of circuit design choices.

IWA: In what way being an instrument maker/player helps in the assessment of the sound quality? Are there disadvantages?

LT: I have developed a sensibility for timbre. I know what I want from my system but not always how to get it, that’s another story. There are similarities, it’s a question of controlling resonances.

IWA: Your brain/heart-ratio regarding digital versus analogue playback?

LT: Nothing to answer, today I use both techniques.

IWA: What meaning it has to you how your system looks? There are cars etc. that especially architects fancy; is there an architect way of doing this hobby?

LT: What I have done is just to use my skills as an architect to domesticate a system based on professional sound components that would otherwise seem alien in a normal living room.

I put some effort in this and also my wife has contributed to the loudspeaker design. She wanted them broader and lower.  I think the system has to be visually present in a discrete way resembling traditional furniture.

I have used natural oak and white linen front and back on my dipoles. White makes the objects seem smaller. I think black can be sober in some settings but it tends to suck if used on big horns. That said, I think loudspeakers has the right to be objects that fill the room if you are a music lover.

Have you ever reacted against a Steinway in a flat, or bookshelves filling the entire wall?

IWA: Thanks Lars for sharing your thoughts with our readers!