Dear @jetter : Yes , those vintage speakers are really good and mines are even better due to my self modifications that I next explain along a little history behind ADS and behind the L230s:
" A/D/S/ (Analog & Digital System) History
In 1966, a brilliant physicist, Dr. Godehard Guenther, came to the United states to work for NASA. Being an accomplished pianist and possessing an intensive passion for music, Dr. Guenther was disappointed with availability of high quality, cosmetically appealing audio products. He sent home for his Braun hi-fi system and soon his friend and co-workers were all asking if these products were available in the United States. He had Braun send a few systems and it quickly elevated to container loads. Godehard was awarded sole distribution right for Braun hi-fi in the United states.
Dr. Guenther left NASA and move to Cambridge, Massachusetts in 1974. He started importing drivers from Braun and Id the assembling and selling of the finished products in the United States. Eventually, he sourced all components and began designing and building his own products sold under the a/d/s/ name. "
So those drivers and specially the tweeter and main midrange domes are just unique an unavialable and ADS used only in two speaker models: L 2030 and L 1530. We just can’t believe that those vintage domes can performs with that so high quality levels, we can swear are today best top drivers.
Btw, latter on Ed Meitner was the chief engeneering and ADS electronics appeared as were the Atelier line and Museatux one. My L 2030 were designed by Mickey Kelly that gone out from ADS to start Aerial Acoustics till today.
The L-2030 " seen " the ligth thank’s to Telarc LP recording group whom talked with ADS to they build a custom made monitors under Telarc specs and that was what ADS did it and named BC 8/11 and was a full range bi-amp design that Telarc choosed to been handled by Threshold electronics. After started Telarc recordings the L-2030 appeared and Telarc used it along the 1530 too, always through Threshold electronics.
I bougth my pair with out knowing nothing about ADS speakers design and I bougth it at Metex Int. in Laredo, TX where I listened mated with Pioneer electronics , turntable and Denon cartridge.
The tweaks/changes to it started to damp internally those big boxes:
first it has " three hands " of a insulation/antivibrational treatment ( like a white paint. I can’t remember the ingredients. ) from Acoustical Magic Company ( it works marvelous ) and took me one full weeek to do it because I have to let dry that " paint " for the second and third hand and I had to take out all the speakers drivers to work with an empty box ( btw, both woofers are wired in parallel but each one in its own sealed space/compartiment. ).
At the same time I change the internal stock damping glass fiber by 10kg ( in each speaker ) of long hair 100% virgin wool and change too the fabric cloth of the grille for a " transparent one ".
It is internally hard wired with Silver Oval by Analysis Plus cable and KCAG by Kimber Kable.
In original stock condition the L-2030 came with some convenience swtichs: one to choose mid-range line source or point source operation, two others to change the SPL in the tweeter and mid-range by -1.5db to +1.5 db and the other switch was for overload protection.
Well, all those switchs just disappeared when I decided to make changes in the crossover:
I take out the crossover ( now is external ) and change all the parts: resistors ( Powertron by Vishay. ), all silver air core solid ribbon ( 5.5 cms. of pure silver. Almost 2kg. of silver in the bigest one. ) Alpha-Core inductors , WIMA FKP 1 and KEMET caps in the crossover, the speakers cables goes soldered directly to the crossover parts. This speaker crossover is tri-hard-wired from the amps output to the 3-way crossover parts and speaker drivers.
In reality are three separate/stand alone crossovers: one for the tweeter, one for the midrange and the other for the woofer, all these hard-wired directly to the amps ( no connectors. ). I added two Dalhquist external tweeters at the back of the speakers running with its own external crossover hard wired to each amp and with the crossover at 6.5khz and up
In the woofers " today " instead that the crossover been with the inductor alogn its caps I take out the caps and connected in series only the silver inductor with no caps.
From 4-5 months now the L-2030s re wired for point source operation and what can I say: just phenomenal/awesome. Yes, maybe you could be foolished by your ears listened to these speakers, even me because all the speakers surrounded system performs at the same quality level. No, it's not perfect, nothing it's.
Wired as point source permits that the inductor in the midrange could goes out ( the diagram says that ) but till today I did not because I preffer to mantain mid-range IMD as lower I can because with out the silver inductor the mid-range can goes deeper in frequency. Maybe some time I will test it.
These L-2030s runs from 80hz and up and the bass frequency is handled by two Velodyne active HGS-15 subwoofers that were modified too and where its woofers are made of paper as the L-2030. I do not change those subs because its very low THD at full power ( over 120db at 16hz. ) of only 0.5%. Subs crossed at 95hz.
These subs are just in front of the speakers looking in between face to face,
Btw, there is no additional external high pass crossover, this was solved internally on each Levinson 20.6 monoblock at its input with one FKP 1capacitor along a Vishay naked Z foil resistor.
@mijostyn I already check the DEQX and yes it’s a good option, thank’s.
R