Flatline Design Model 175, Designed by Lewis Muratori

Nearly three months ago, I lucked into ownership of a very rare pair of hybrid ribbon speakers, Flatline Design Model 175s. Information regarding these on the internet is not only limited, it's effectively non-existent. The previous owner informed me that only 30 units were built and sold, to which both of mine are serial number 003 (later units used consecutively numbered pairs). An extensive internet search revealed only a brief reference to a pair of Stereophile articles on the speakers by Russ Novak (Full review is found in the December 1994 issue of one of the last pairs built) and another review of his wherein his pair of Flatlines was part of the test system. So, to correct this absence of data, I've decided to post pictures and specs as I have managed to locate and take.

The Basic Specs:

The Model 175 takes it’s designator from the 175cm long true ribbon hung on the side of the 6’ tall cabinet. This ribbon runs from 350Hz to 44kHz, being crossed over at the low end by a first-order 6dB/octave crossover with notch filter. For the rest, a 5” Peerless 146MR2608 polycone driver serves midbass duty from 100Hz to 350Hz with the idea being a smaller cone in an acoustic suspension design could serve as a sufficient intermediary driver between the ribbon and woofer. The 10” woofer, unmarked but looks like a Peerless as well, is actually side mounted firing out between the speaker towers and uses the majority of the main tower as it’s cabinet. Overall construction is pretty good, but modifications have made it even better with ~3/4” front and inside panels and ~1.5” for the outside side and rear thanks to an additional layer MDF installed by the previous owner. The inside is braced in several different ways (using what may be metal pipes covered in Dynamat to minimize elasticity) and all panels are covered in Dynamat. The crossover is mounted on a MDF tray in its own chamber at the bottom with a black plexiglass connection plate so that the whole crossover may be readily pulled out for modification.

This is my schematic with the parts list below; I haven’t an original to compare to and some fairly extensive modifications have been made to these. The woofer and midbass share the same connectors. The inductors have no markings on them to indicate their values:

Now, time for some pictures...

My pair of Flatline Designs in their prior system:


Side view:


The connection plate and crossover drawer cover:


The right channel's cone midbass driver:


The right channel's woofer:


Crossover drawer slid out from its separate chamber:


If I learn more about these rare speakers, I will add to this thread.

- JP

Bitchen speaks, JP. Muratori's name pops up associated with a Melbourne AU audio club/group/gang. He may be some sort of hired gun, sort of like Bart Locanthi (remember him?) going from JBL to Marantz to Pioneer. In any case, keep us up to date on getting them up and running.

Yep, I've slowly been making progress on tracking down Muratori. He's also recently designed a pair of conventional cone speakers that were very well received by the Melbourne club and wrote an article for Hugh of AKSA amplifiers (real nice guy, btw) about affordable, but excellent speaker cables. Just a week or so ago, I was contacted by an Australian audio enthusiast who tipped me into the fact that Muratori has been working for/with Tom Manning at Speaker Bits (the company that once tried to sell my foam surrounds for my Tannoys at the ridiculous price of $270) in speaker repair. When I return from my trip, I intend to pursue that route further to see what more I can learn about these speakers, as what information there is doesn't always agree even with what's contained within the Stereophile review.

In any case, the Flatlines are running just fine and singing. The only repair problem initially was with a soldering heat sink clamp thingy being accidentally left in the crossover of one of the units when the caps were bypassed with the InfiniCaps that created an intermittent short in the one (must've been by a minor miracle the previous owner didn't blow an amp out with these).

The issue I currently have with these speakers is that a 5" monopole cone driver just cannot make for a coherent match with a near 6' tall ribbon. As such, the sound just doesn't sound right close up and when one backs off, the differences in SPL decay are profound even a few feet away. Nevermind that a 5" cone just cannot provide the body in the midbass that the Tannoys taught me to expect and what makes for realistic sounding pianos and tympanis. The bass from the side-firing woofer just doesn't go deep enough with sufficient power for my tastes and doesn't quite merge well with the midbass either.

Granted, the Flatlines are still excellent speakers and were an excellent buy when they came out (the ribbons likely costing a very sizable amount of the MSRP on their own). I'm just overly picky.

- JP

Big pannels ( Both electrostatics , ribbons or quasi-ribbons ) and cones very rarely mate properly.

I´ve been less than impressed by most of the Martin Logans I´ve listened to.
I also auditioned a pair of Quad ELS 63´s with Gradient subs, and something just wasn´t right. The ELS on their own are amazing speakers, though.

OTOH smaller ribbon tweeters and cones are a more coherent match, as I witnessed with several Infiniyty and Visaton models.

Keep looking, JP, and I believe one day you might find the speaker for you in the form of large horns with compression drivers for mids / highs, fed by multiamps with active crossovers. You´re still young, tou have time...

Jorge

it's simple! just run the Tannoys with the Flatliner ribbons.

there you go, its just that simple

elroy

Could try that, but it'd still be mating a monopole to a dipole and so continue those problems. Besides, the cabinets the Tannoys are in are very resonant and port loaded to boot resulting in much less than satisfactory midbass/bass. In many ways, mating Maggie panels to the ribbon would be much less work to build the support than new boxes for the Tannoys (as I would feel the need to overbuild them anyways).

So, the hunt for appropriate panels continues.

- JP