|
Unlike many other people, my journey did not start with electrostatic panel speakers or the like.
When I was a child, my brother and I were sharing a room. He had inherited a Dual turntable from my mother that she had gotten for her confirmation when she was a teenager. This turntable came with a set of speakers that I believe somehow could be fixed to the device when moving it. Most of the time those speakers were sitting in a bookshelf. But occasionally, we or I moved them out and played them on the table top or on the floor. When placing those speakers more or less free standing they changed their sound dramatically. It became airy, transparent and somehow more natural.
When I today recollect the details of those speakers then I would say that they were some kind of a semi-open construction because they had slits at the back side, which I believe was made of thin sheet metal. They had an oval full range maybe a 5" x 8" woofer with no crossover and a 2" cone type dark yellow-ish (epoxy drenched fabric cone) tweeter that was crossed with a single cap. The housing was a simple U-shaped baffle made of the cheapest wood covered with a leather like appearance PVC foil and the back wall with the slits must have acted as some kind of flow resistance thus giving this speaker a cardioid-like polar pattern.
The speaker did not become a reference for me because I was only a 6-10 year old school boy not knowing what speakers were all about. I only observed that change of sound resulting from moving the speakers out of the shelf and also when turning the head and moving around the speakers. But it was clear that these speakers sounded somehow completely different than anything else that played music at home at that time.
Years passed and I started an apprenticeship in consumer electronics at Deutsche Thomson Brandt GmbH (mainly Thomson, SABA, Nordmende and Telefunken). By that time I had nearly forgotten this “early auditory experience” because during my last year in school, I sometimes spent time in Hifi shops listening to the typical speakers of the late 80s while waiting for the train or just for the heck of it. Amongst them were products from MB Quart and Quadral and they sounded good to me; not only because the CD has had its final break through. In the 2nd year of the apprenticeship a new supervisor joined the company fresh from university and his hobby was...building speakers. So some colleagues and I formed a group and the new trainer taught us speaker basics after work. That was the beginning of the 90s. Applying what just had been learned about closed and bass reflex boxes, I ripped the Dual speakers apart to give them a new home. Bass was gained but all of this airiness and transparency was gone when I mounted the drivers in a closed baffle. I did not care too much because good bass was (and still is) a desirable attribute.
Since we earned some money, we eventually could afford car stereo systems, which was a big thing for us. Ever since, I learned a lot about car acoustics. Additionally, I invested some money in a set of drivers to build my 3rd pair of speakers around the end of the apprenticeship. The 8" mid-woofer was a brand new Monacor SPH-200KE. When it arrived I hooked it up to my DIY Hifi system with no crossover to check how it would sound like and to get an idea how the final speaker could sound like (OK, that was naive...or maybe not in hindsight). I just held it in my hand right in front of me...and there was it again...this airiness, transparency and clarity. There was no bass but the feeling of my vibrating hand somehow filled in for that sense. They ended up in a 30 something liter bass reflex 2 way box and all of the “special” attributes were gone again. They were OK and lasted quite long for me (after upgrading to Seas NoFerro 900 tweeters) but beside the standard sound, I also didn't like the room modes they excited and moving them around did not fix it completely.
Meanwhile, on the quest for better sound, I had auditioned the first Scala right at the Revox company, a huge fully active speaker with negative impedance power amps, digital signal transmission from the pre-amp and digital (IIR) filters. Well, it was loud and clean. A great speaker and fantastic technology at that time but just no special or natural enough sound. Today I know that the venue where we auditioned it was well damped and way too big compared to regular living rooms. So the listening impression was dominated by direct sound.
Coincidentally, it featured the same (or slightly modified) tweeter that I had used first in combination with the Monacor SPH-200KE: a WHD CAL26/5, from a company (Wilhelm Huber & Söhne Deißlingen) that used to manufacture HiFi drivers very close to where I live.
During my course of studies (medical engineering) the main focus was on electronics. My buddy and I were building e.g. ECG and EEG amplifiers. A lot was to be learned about low noise/high gain amplification, sensible grounding schemes and shielding techniques. For those amplifiers we used OP amps as such, as instrumentation amps, or isolation amplifiers to cater for galvanic separation.
Another auditioning category was a pair of Martin Logan’s (panel and closed sub) and later a similar DYI speaker built by a colleague from HP. Both were really good in total but they were still not the final answer. Other auditions some time before and in between covered the typical speakers of the 90s. One of them was a Quadral Titan, which inspired a design for my brother (he just liked the appearance). We ordered drivers (Visaton TIW360, Audax HM170Z0, Seas KT19F) for such a bulky 3 way tower (construction sketch from back then) but they never made it into a product I could consider final. The design had undergone numerous promising changes but finally, because still unsatisfied, I decided to go fully active. To fill in some missing theory about active correction networks, I started reading Siegfried Linkwitz' page. As a test balloon, I turned my two way bass reflex into a two way fully active closed box with a decent result. I had read about Phoenix, Orion and Pluto meanwhile and one day, I decided to start all over again because all that I had been reading, formed a new and more complete sense about speakers in my mind. So I assembled a dipole speaker with my good old Monacor and one Seas NoFerro 900. I added two reasonably priced 10" sub-woofers and bought a digital crossover that allowed me to change parameters on the spot. I was simply impressed after seconds of listening. What I could hear from a single speaker was plain stunning. And there it was again: airiness, transparency, clarity and…a new sense of spaciousness. The frosting on this new sweet cake finally was the backfire tweeter. I could switch it on and off for comparison and as soon as the final level setting was found it was a really satisfying experience that made me simply smile.
With the other set of “leftover” drivers I built the prototype of an omni pole and again with great and pleasing results.
These are the key experiences and milestones of a 20+ years DYI loudspeaker journey. The other stuff I designed, was and is important for me because it provided the basic knowledge about building speakers; but that does not belong here. What will evolve out of all this, will be visible in the projects section of this page.
However, one thing is for sure: There is no way back to regular shoe box speakers.
6.283
|
