Rockvale Technologies
RCVTECH is founded by a group of audio enthusiasts with a goal of creating audio speaker systems which they like to listen to themselves.
The story started from the listening fatigue. Like most people we googled the possible solutions e.g. trying better audio and power cables, cable lifters, power filters. etc. We switched DAC and amplifiers from the units that cost hundreds to the units that cost thousands of dollars. We have tried vinyl and tapes players without noticable changes. We could not afford going to next price level, so at some point we decided to apply our electical engineering background to troubleshoot the possible issues. We began from the device that produces the actual sound - the loudspeaker. We opened up the speakers, pulled out the crossovers and that's how it all began.
After replacing the MPP and Electrolytic capacitors with the entry level audio grade ones we found the sound clarity improvements as if the speakers used to be wrapped in a wet towel and it was now removed. The only issue was that the audio grade capacitors would not fit to the PCB boards being 3-4 times bigger than the stock units. We then tried changing the inductors, resistors and wiring that gave us improved base and even more clarity of the sound.
dWe also found that actual measurements of the most stock loudspeakers we had encounters with frequency response is mostly never +/- 3 Db. One set of speakers made by a well known brand claimed to reach up to 20KHz while the actual measurement found it maximum was 16K.
We also found issues measuring the speakers impedance. So called 4 or 8 ohm speakers usually have that value at 400 to 500 Hz. But at 2000 to 3000Hz the impedance of the same speakers can be 12 ohm or higher. In some spots the impedance can also drop below 3 ohm at which pointt some amplifiers start mulfunctioning.
We also came to realize that 5-10% tolerance of the inductor and capacitors values can make quite a difference. For example 10uF capacitor with posted +/-10% deviation could actually be either 9uF or 11uF which translates into crossover frequency moving up or down by 400Hz!.
So we decided to look into making our own crossover components and designing our own crossovers . It took several years of research and development. Some equipment we were able to buy, some machines we ended up making ourselves.
We found this very useful knowledge as we now have a deep undestanding of the internal functioning of inductors and capacitors, how their construction and materials affect audio signal and how to best apply them to the modelling of the crossovers.
Each crossover we make follows all the design values i.e inductors, capacitos, resistors are all made to be 100% of the required values. We make them is small batches for each build.
When designing the shape of the speakers we proudly follow the published works of Dr. Harry F. Olson. In his AES Paper presented pn October 27, 1950 he concluded:
“The response-frequency characteristics, which depict the performance of a direct radiator loudspeaker mechanism in various enclosures of fundamental shapes, show that the outside configuration plays an important part in determining the response as a function of frequency. For example, in some enclosures the variation in response produced by diffraction exceeds 10 db. ”