Freds.Bands
Live Music Listener
This appears in the Oklahoma CL listing. Keep in mind that some of this is opinion and maybe even conjecture I've missed commenting on. I have edited out, via ...., the sales talk for this system and bracketed [] my own corrections/additions. I didn't check to see if it's OK 
to post here. But his early Rectilinear IIIs look very nice to me.
More to come.
to post here. But his early Rectilinear IIIs look very nice to me.These are the highly coveted early Brooklyn version of the speaker before the company moved to the Bronx... They are not only beautiful sound, but unlike most current speakers, beautiful furniture. They are large and very heavy. The 12 in woofer alone weighs more than 22 lbs. I have never gotten tired of listening to them in all the years I have owned them. ... They are 34" high, 18" wide and 12" deep. They weigh close to 100 lbs [~80] each.
Rectilinear Research
Model III
I meet many vintage stereo collectors who have never even heard of the Rectilinear Research brand, yet the vast majority come away rather impressed after a short audition of the model III.
There are four versions of the model III and for the longest time, these speakers did not surface very often. Lately I have been seeing many pairs show up both on eBay and Craig's List, yet every set has been the last version made which started in 1971 and most are rather beat up.
The very first version (1967) is the most valuable and hardly ever found, the pair offered here is almost as hard to find and is the second version (1968), while the third version (1969) is semi-rare yet does pop-up now and again. While the extremely common 1971 version can be found rather easily and usually for only a few hundred dollars, they are not as highly valued by collectors. [are we collectors?]
For those you who might be interested, a brief history on the model III is posted at the very bottom....
The design goal of the Rectilinear III was to create a reference standard with special emphasis on the widest possible dispersion of sound and unimpaired performance in unusually large rooms. By comparison, the L100 of the same era was specifically designed not to be a highly accurate speaker as it copied the flawed Altec Lansing 604 design and was a close field monitor. [I think they were also to compete with the AR 3.]
As the L100 was becoming popular at the very same time as the model III, Rectilinear very politely comments on the JBL flaws in one ad without actually mentioning any names. Rectilinear directly pointed a finger at JBL by stating the new "West Coast Sound' was inaccurate with overly bright midrange and boomy bass, which was a fact. IMHO, when these two speakers are compared side by side, the model III simply outperforms the JBL L100 & 4311 in all areas plus allows for hours of non-fatiguing enjoyment.
The model III cost just under $600 [$578] a pair way back in 1966 with Duke Ellington personally endorsing them by stating The sound is so natural that I feel I'm sitting there with the band! ....
The moving-coil loudspeaker was invented in 1925, yet the stereo era of hi-fi did not start until 1958, all recordings before this time were mono. By the mid-sixties there were very few dynamic speakers on the market which could accurately reproduce stereo sound without adding coloration to the playback. The Rectilinear III really stood apart at this moment in history by offering a very neutral product that did not add or subtract to the sound of original recording. [Others mfgrs claimed that also.]
While no one will claim this system is the best speaker using today's ultramodern (expensive) standards, this vintage speaker is very enjoyable to play due to the smoothness and accuracy of sound, plus having such a strong bottom end which is often found lacking in many early speakers.
Despite being a bass reflex design cabinet, the Rectilinear III is a relatively low-efficiency system requiring a fair amount of clean amplifier power. I recommend 50 watts as the minimum, but they can be run on as little as 20 watts. Yet this comes with a caution, under powered amps will kill tweeters if pushed into clipping, so do not crank up the volume.
Critical listeners who prefer program material at high levels (loud) will most likely want to use equipment near the maximum of 100 watts per channel. Yet be forewarned the other way, do not overpower the speaker as the midrange voice coil will overheat and start to rub.
...
Cabinets & Grills
.... The quality is a reminder of the good o'l days when solid construction was the norm! The cabinet panels are braced on all four sides plus supported front to rear to restrict vibration. This bracing plus the mounting of the woofer off-center in the cabinet virtually eliminates any cabinet resonance from the lower frequencies.
To further isolate the lower frequencies, the midrange driver is suspended [in a separate plastic cup) in the cabinet with RTV glue [and damping material] to dampen out any undesired vibrations. As the front baffle is removable, the cabinets tend to leak air which impacts bass response. [He says, "A sealing gasket has been installed in both speakers to eliminate this problem and can be seen as the black foam strip in the photo." May be a good idea.]
The grills on the model III (and many other RR systems) were not designed to be removed by the consumer, being nailed to the front baffle with small brads. Unfortunately many folks do not know this fact and end up breaking the delicate frames trying to pry them out. [I like the idea of small magnets or even velcro to replace the nails.]
This early pair has the thicker frames unlike the thinner and more fragile frames found on the late model, yet small fractures still existed which compromised their strength. [He says,"A thin support of 1/8 inch plywood has been added to the perimeter of both frames to restore the integrity. The OEM cloth was faded which is very typical, yet by simply reversing the fabric the original orange-black-brown tweed looks new! Maybe two more good ideas.] Both metal grill badges (not the late model plastic type) are installed which is a typical flaw for these speakers [that is, people losing them].
Drivers
The woofer was designed to move sufficient air while maintaining a fast transient response for solid output down to 20 Hz in the tuned enclosure. The woven cloth surround will never rot plus permits 1 inch cone excursions without running into nonlinearity issues. The woofer operates from 20 to 500 Hz and is rolled off at 6 db per octave [is it 6 or 12 dB? must find out as it affects the capacitor size] to keep it out of the midrange where coloration could become apparent. The DCR of these woofers is 11.2 & 11.3 ohms. [I've heard that before; odd for 8 ohm woofers.]
The midrange driver which was made in Holland. This design provides a smooth transient response between 500 Hz and 3 kHz which is also attributed to the special European paper and an unusually light voice coil. This exceptionally neutral driver covers the musical characteristics which differentiate the vast majority of instruments and vocals. The DCR on these drivers is 3.6 & 3.8 ohms.
The four paper cone high frequency drivers made in Denmark cover the remaining range from 3 kHz all the way to 18.5 kHz. This classically simple design uses a very light cone and voice coil creating a smoothness not found in more complex designs, the thin aluminum dust cap weights only .01 of a gram. By widely spacing these four tweeters from top to bottom and around the front baffle, the upper frequency sound is dispersed over a very large area. The DCR of the 8 tweeters is 7.0, 7.1, 7.2 (x3),7.3 & 7.4 (x2)\
Crossovers
The crossovers use air-gapped iron-core chokes coupled with capacitors to accurately control each driver, along with having a single attenuation control on the back panel for the four tweeters [He says, "which has been cleaned and tested to assure smooth and noise-free adjustments from end to end. Typically I replace the vintage capacitors with high quality audio grade components, yet did not on this set as serious collectors prefer the OEM parts." We do?]
The OEM input posts only allowed for 16AWG wire or a spade lug.
More to come.
Last edited:
