('79-'82)  $1100

Obtained from the original owner and in excellent cosmetic and operating condition, this pair of legendary JBL L-150 certainly need no introduction.  

Serial numbers are sequential #18134 / #18135. 

All drivers are original, and in great shape. Woofers and passive radiators were professionally refoamed about 10 years ago. The crossovers are 100% original and unmolested. Level controls work as they should. Cabinets and original grills are near perfect.

Drivers: 128H woofer (12")
               PR300 passive radiator (12")
               LE5-10 midrange (5.1")
               033 tweeter (1")

The L-150 was only made for 2 years before JBL released the L-150A which is a totally different speaker with different drivers and a metal dome tweeter compared to the L-150 which features soft dome tweeters.  Although it's very subjective, many "audiophile ears" have claimed that the JBL 033 tweeter used in these is much more natural sounding than the metal one used in the 150A model.

JBL's goal in making the L-150 was to offer a speaker that could approach the sound level and experience of a live performance. They sound terrific at low levels, but with some righteous, clean power behind them, they can be unbelievable. 

Essential specs:
Type: 3 way, 4 driver loudspeaker system
Recommended Amplifier: 300 watts (max)
Crossover Frequency: 1000, 4000Hz
Impedance: 8Ω
Sensitivity: 88dB
Dimensions: 42"H x 17"W x 13"D
Weight: 90 lbs each

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(England '03-'06)  $450

*Why bother with frequencies that only your dog can hear?

Pristine cosmetics, completely original and in perfect operating condition, this pair of Tannoy Sensys 1 speakers present a soundstage that's hard to believe considering their relatively small size. 

With the introduction of Sensys, Tannoy had combined the core element of sound quality with the other equally essential ingredients, cutting edge technology, clean aesthetic design and affordability, to produce a class leading range of exceptional loudspeakers. Avoiding visual tricks that often cause designs to quickly date, the refreshingly uncluttered appearance of Sensys is as reassuringly unpretentious as it is timeless.

The Tannoy Sensys 1 features Tannoy's Wideband technology and follows a minimalist signal path by virtue of the inherently simple crossover.  This simplicity is needed as the drivers are in a naturally phase correct alignment and the integrated design allows for a seamless frequency transition. Sensys 1's high power handling capabilities and high efficiency make for one extremely dynamic package that became a classic and a favorite of audiophiles. 
With a 7” cast chassis mid bass driver and 1" WideBand high frequency unit this is a bi-wireable stand-mount speaker of immense ability. Combining tremendous bass weight and impact with natural open voicing and sound staging.
~Drivers: (each enclosure) single 25-micron titanium dome tweeter, (neodymium magnet system) 
~single 7" mid-bass multi-fiber paper pulp cone

About Tannoy's WideBand technology...
Tannoy has pioneered wide bandwidth audio reproduction in its high-end loudspeaker designs. The undisputed benefits of extended high frequency performance have been recognised by audio enthusiasts and recording industry professionals worldwide. Tannoy has received many international awards for products utilising Wideband technology. Although developed in parallel with the emerging technologies of extended bandwidth SACD and DVDA players, their engineers have long since recognized the improvement that a Wideband Tannoy SuperTweeter can make to a system, even when using bandwidth limited conventional analogue or digital recorded software.

The key element to understand first of all is that Wideband performance drive units are not there simply to increase the amount of high frequency information you perceive, the acoustic benefit is much more subtle than that. It is the enhancement of the frequencies within the accepted audible band that makes this technology so special.

*Why bother with frequencies only your dog can hear? 
This question, often asked, took them to the very heart of what Tannoy Wideband™ technology is all about: Musical instruments produce considerable energy above 20kHz and, with effects of harmonics and overtones, achieve frequencies well beyond what might generally be considered as the limit of human hearing. For instance, the over 20kHz energy of a trumpet, fitted with a particular type of mute, does not drop into the noise floor until 100kHz. Violin and oboe exhibit energy above 40kHz, while sibilants in speech can also be shown to have energy above 40kHz.

Research has shown, through the measurement of brain wave activity, that humans do perceive ultrasonic components within music. Concluding that the mechanism of ultrasound transmission is through bone conduction, probably via an organ in the inner ear, called the saccule, to the cochlea, the organ responsible for hearing. In addition, Wideband technology reduces phase error and significantly improves transient performance below 20kHz. This leads to increased tonal accuracy throughout the whole frequency range, even bass information is faster and tighter, effectively enhancing the total listening experience. Music, speech and soundtrack effects have an increased immediacy, airiness and impact, providing a performance that sounds more natural and true to life.

Extreme physical demands are placed on the high frequency unit when performing at such extended bandwidth levels. The need to achieve completely consistent constructional and acoustic quality has led Tannoy to design and produce its own titanium dome driver at its Scottish based manufacturing facility.

Specs:
Enclosure Type: 2-way bass reflex
Recommended Amplifier:20 - 100 Watts
Power Handling (RMS): 75 Watts
Peak Power Handling:225 Watts
Frequency Response: 49 Hz - 51 kHz
Crossover Frequency: 2.7 kHz
Crossover: Type 2nd order LF, 3rd order HF
Sensitivity: 88 dB Nominal
Impedance:  8 Ohms
Internal Volume: 13 liters
Dimensions: 8.3"W x 13.8"H x 11.5"D
Weight: 16 lbs each

About Tannoy...
Tannoy is a British manufacturer of speakers and PA systems.  Founded by Guy Fountain in London in 1926 as the Tulsemere Manufacturing Company, today the company is part of the Music Tribe group of brands.  They eventually moved to Coatbridge Scotland in the '70s.

Tannoy's image is particularly linked to both studio monitors as well as its Prestige range of home speakers. Prestige speakers use Dual Concentric cone speakers and are easily recognized by their "vintage" design. Tannoy is notable for its 'Dual Concentric' speaker design, which places the tweeter behind the center of the medium or bass driver. "Dual Concentric" is a trademark although Tannoy is not the only speaker manufacturer to design coaxial speakers.

In 2002, Tannoy was acquired by TC Group and TC Group was subsequently acquired by Music Group in 2015. Following the Music Group acquisition, it was suggested that the Coatbridge facility would be closed and all related activities would be relocated to Manchester England. In 2016, however, Music Group confirmed that Tannoy loudspeaker manufacturing would continue in Scotland, with a brand new manufacturing facility planned.

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(2012-current)   $2000  *as is

*NOTE:
This was an "open box" purchase of a pair of new XR50 with cosmetic damage from the factory .  As such there is some cosmetic damage with this pair of XR50.  It does NOT affect the sound.   Also, there are no grills available.  Most of the few areas of the damage are on the back and are not noticeable.  One cabinet has damage on the very bottom left hand corner; it has been touched up but upon close inspection it is noticeable.

From McIntosh:
"The McIntosh XR50 is a cleverly engineered compact bookshelf speaker that produces the rich, full sound one would expect from much larger speakers."

FEATURES:
Ported 3-Way Bookshelf
75 to 300 Watts Power Rating

This pair has the red walnut high gloss wood finish.  Unique front panel McIntosh logo may be illuminated when used with McIntosh components. Amplifiers from 75 to 300 watts are appropriate power for XR50. An additional connection passes on Meter Illumination Control for compatible power amplifiers.

https://www.mcintoshlabs.com/products/speakers/XR50

SPECS:
Impedance (nominal): 8 Ohms
Power rating: 75 to 300 Watts
Frequency response: 40 Hz to 45 kHz
Crossover: 500Hz, 8kHz
Woofers: one per enclosure: 6" / Cast Frame, LD/HP®, Poly Cone
Midrange: two per enclosure: 2" Inverted Titanium Dome
Tweeter: 1 per enclosure 3/4" Titanium Dome
Finish: high gloss red walnut,
Dimensions: (W X H X D): 8"W x 17"H x 11-3/4"D
Weight: 19.5 lbs each

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(England '82-'84)   $500

In pristine cosmetic condition, fully serviced & tested, this pair of Bowers & Wilkins DM-17 Limited Edition bookshelf speakers are accurately defined as true mini-monitors. 
They have the desirable walnut enclosures; the unique and very rare factory stands are included.  

The hefty and hermetically sealed enclosures were designed as 2-layer structures consisting of 1/2" thick high density particle board, 1/4" Bitumen pads and a 3/4" thick front baffle assemblies.

At 85 dB, they are not considered very efficient; as such, they need some very good, solid amp power to make these monitors do what they were designed to do!  Any concerns about too much amp power is taken care of because B&W was clever to include a built-in "Audio Powered Overload Circuit (APOC) system".  
NOTE: The APOC system reads the voltage applied to the voice coil of each unit, and when the limit is exceeded, the relay operates to cut the input signal, thereby preventing thermal damage due to overload. The red LED next to the B&W logo lights up while the APOC system is operating and automatically recovers after an overload condition has passed.

It should also be noted that the DM-17 was one of the very first of the B&W designs to incorporate the tweeter housing isolated on the top of the cabinet.

The drivers:
~The 6" mid-bass driver is made of ferritic material that had been treated with the same dumping treatment as the woofer. The ferritic material is made of highly crystalline, highly rigid polymer that provides tight bottom end sound pressure levels.

~The 1" dome-shaped tweeter is installed in its own protective dome screen and located on the top of the cabinet. Constructed of woven polyester fiber due to its excellent characteristics and, thanks to the use of a strong magnet, the overall volume was kept to a minimum.

Crossover network:
The DM-17 uses a butterworth 24db/oct. crossover with matched components.  B&W was famous for measuring each capacitor and coil so they could match them exactly - if the marked value was only within 10% they would get them to within 1%.  (another reason that B&W is so widely admired for their premium speaker designs)

From the B&W dealer sheet: (original MSRP $900/pair)
"The DM17 Limited comes into the B&W range equipped to occupy the top position among compact two-unit monitors. Despite its miniature dimensions, its performance may be judged by standards as exacting as those applied to full size monitor systems. For those whose ear demands such standards, but who's listening room is of limited size, the DM17 Limited now clearly becomes the loudspeaker of choice.
Regarding the placement of the high frequency driver on the top of the enclosure; it avoids the situation with normal cabinet construction, where sound waves from the tweeter not only radiate towards the listener but also travel along the baffle surface towards the cabinet edges.
When sound waves meet sharp cabinet edges they re-radiate (a process known as diffraction) and, due to the time delay, interfere with and time-smear the sound coming directly from the drive unit.
Having the tweeter separate from the main cabinet also allows its time-alignment with the midrange driver to be finely adjusted so the two outputs add perfectly in phase through the crossover region."

Essential specs:
Minimum amp power required:  40 watts
Nominal Impedance: 8 Ohm
Frequency Response: 85 - 20000 Hz 
Sensitivity: 85 dB
Dimensions: 16"H x 10"D x 8.5"W
Weight: 20 lbs each

About Bowers & Wilkins...
The sleepy coastal town of Worthing in South England might not look like a hotbed of 1960s freewheeling experimentation, but for audio fans it’s a place that’s synonymous with innovation. Thanks to the first Bowers & Wilkins speakers built there in the early years of the company, music lovers could experience albums such as Sgt. Pepper and Pet Sounds in new, mind-expanding depth and clarity.
In 1966, John Bowers set up his company with his partner Roy Wilkins and  began assembling speaker systems in the workshop of their electronics shop and designed their first speaker, the P1.  The profits from this beginning allowed them to invest in new calibration equipment.  By 1968, the high quality "Domestic Monitors" (DM1, DM3) brought more recognition from the audiophile community.In the 70's, with John Bowers at the head of the company, things really took off...with the development of curved cabinet forms and the use of new cone materials such as Kevlar, they hit it big with the Model 801 which almost immediately became the reference speaker of choice for many of the world's leading recording studios. 
Also, the first model DM6 from acclaimed designer Sir Kenneth-Grange appeared in 1976.  The later DM7 and DM17 were the first that featured the iconic "tweeter-on-top" that's still used today.  
In the 90's the appearance of the (now very famous) B&W "Nautilus" which totally upended the preconceived notions of speaker design.Even though John Bowers passed away in 1987, today, in the so-called digital age, B&W just keeps moving along with its latest versions of the Diamond Series and so much more.

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(late 70's)  $300

In very good cosmetic condition and fully operational, this pair of custom built Acousti-Craft cabinets each features a single 12" Electro Voice SP-12B woofer and single 1" cone tweeter.  They also feature beautifully constructed fine cabinetry with original factory cane weave grills that were popular in the 60's & 70's.

The main drivers in both of the enclosures are the EV-SP12B woofers which was in the same family as the 12TRXB coaxial driver used in the legendary EV "Aristocrat" model first introduced in 1957.  This driver was also used in TQWT, bass reflex, horn enclosures or open baffle cabinets. They are rated at 95dB efficient and 16 ohms nominal impedance.  That means they would be perfect with low power tube amps.

The Acousti Craft cabinet design is fully sealed with thick acoustic baffling material lining all sides, top & bottom.  The Electro-Voice SP-12B was primarily produced between the late 70's and early 90's.  However, specific model variations might have been available for a slightly longer period depending on the market and production runs. 

Key points about the Electro-Voice SP-12BPopular model:It was considered a high-quality, professional-grade speaker used in various live sound applications, including concerts and large events. Design features:The design offers a wide frequency response and powerful sound projection. Production shift:As technology advanced, Electro-Voice introduced newer speaker models, leading to the gradual phasing out of certain units.
Basic specs:
Dimensions: 21"D x 23"W x 31"H
Weight: approx 40 lbs each


About Electro-Voice...

In 1927, Al Kahn and Lou Burroughs established the company Radio Engineers in the basement of the Century Tire and Rubber Company in South Bend, Indiana. At this site they first began producing microphones to use in their PA systems, and later to sell to people who couldn’t but them any other way.  Incorporated on July 1, 1930, Electro-Voice was involved heavily in installation and rental of public address systems for churches and other public buildings. Politicians especially had become aware of the power of the microphone to increase their reach, and demanded ever more powerful PA systems.  Microphones were originally manufactured only for EV’s own use, but within a few years the balance had shifted and manufacturing microphones for sale to others had become the more important part of the business.  Thus, the EV branded microphones were used by most of the professional recording studios at one time.  They moved into loudspeaker production as a natural progression of the audio market.
Ultimately, Electro-Voice speakers were THE super efficient speakers of the 60's and early 70's and many well known companies like Klipsch used them in their larger models. 

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(hybrid) (1987) (rare, mint)  $700

The Maxim III-H (hybrid) is best described as the last and best configuration (as designed by *Dan Siefert) of a two-way, compact system featuring 40-Hz resonance woofers, low IM distortion, low group delay and with high power handling capability.

The enclosures:
Essentially a 2-way system, these front-ported, black-lacquered grained oak, tuned-bass reflex enclosures (with radius edges) are based on the special relationship 4:5:6, which minimizes internal nodal reflections. Remarkably solid, 3/4" particle wood and high density fiberboard, plus rigid internal bracing. The narrow baffles provide excellent dispersion and enhanced imaging. They have sequential serial numbers for a matched pair.

The drivers:
Specially designed Dynaudio 6.5" woofers (18 oz ferrite magnets, 1.25" voice coils) feature ultra-compliant butyl surrounds combined with polypropylene cones containing proprietary inert damping compound that makes them twice as thick as most woofer cones.The SEAS tweeters (8.7 oz ferrite magnets) are 1" special aluminum domes with polyamide surrounds, this upgraded tweeter design makes them hybrid, or, the "H" model. (see Dan's technical explanation below)

The crossover network:
3.3 kHz, conjugate-compensated, first order, minimum phase

Specs:
Frequency response: 46 Hz ~ 22kHz
Impedance: 8 ohms
Power handling:  up to 250 watts
Sensitivity 86 dB @ 1 watt
Dimensions:  13"H x 9"W x 11"D
Weight: 18 lbs (ea)

Finally, the Maxim III-H (Hybrid) is true high quality system, 100% made in USA. They easily rival the quality of famous German/American speakers like Visonik, Braun, ADS, B&W, etc. 

The story:
Several years ago, we came across a pair of unknown (at the time) Siefert Research speakers. We were intrigued enough with the design and sound to jump online and (eventually) track down the designer, Dan Siefert. *(see bio below).
He was kind enough to reply with a wealth of inside information way beyond what was available online. He recommended looking for a pair of Maxim III. He also sent us a package with original spec sheets, sales sheets and technical design information about the Maxim lineup.  Back in December 2018, after finally finding a mint pair of Maxim III(H), we contacted him again in regards to what the "H" meant on these Maxim III(H) speakers.
Dan's reply: 12/27/18"
"With the Maxim III-H you have what I consider the best series of Maxims. The "H" stands for hybrid. Looking at the tweeter you will notice that the dome is aluminum but the surround (outer edge) is not.  99.9% of all dome tweeters are a single piece construction. So, if you have an aluminum dome (high stiffness), the surround would also be aluminum.  Aluminum makes a great diaphragm but a lousy surround (where you want high compliance, not high stiffness).  In the '80's there were almost no hybrid construction tweeters. Today they are somewhat more common. Bottom line: the hybrid tweeter combined the high stiffness of an aluminum dome with the high compliance of a polyamide surround making a very good speaker even better."

Stereophile magazine review 1985:
"There are very few loudspeaker systems of any price that don't make a critical listener accurately unhappy when he or she returns from a live concert to put on a recording. The Maxim is, amazingly, one that doesn't. In fact, of all the speakers in this price class that I have heard. I would say that Siefert's Maxim III is probably the most successful design of all. Mated with a suitable power amplifier, and not pushed too high a listening level, it is one of a small handful of moderately priced speaker systems that can make most audiophiles (and practically all music lovers) quite happy for an indefinite period of time. Recommended."~J. Gordon Holt (Stereophile magazine July 1985) Read more at https://www.stereophile.com/.../siefert-maxim-iii...

About Siefert Research...
Dan Siefert began his engineering career in 1975 at Great American Sound Company, designing high-end solid-state audio pre-amplifiers and power amplifiers.In 1983, Dan founded Siefert Research in Los Angeles, designing, manufacturing and marketing high performance loudspeakers...not through dealers but direct to customer.In 1986, he joined Harman International Industries, Inc . as a Senior Systems Design Engineer.While at Harman, Dan brought several speakers to market for professional, consumer and computer/multi-media applications. He was assigned to the Research and Development department, reporting to Dr. Floyd Toole. Dan then focused his attention on measurement technologies and contributed to the development of Harman's advanced subjective and objective measurement techniques.In 1996, he founded One on One Technical Products, Inc. and currently in 2018, as CEO, providing engineering services to the Consumer Electronics Industry. He is a member of the Audio Engineering Society (AES), the Acoustical Society of America (ASA) and the Custom Electronics Design and Installation Association (CEDIA). Dan is also a certified THX Home Theater Products developer.

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