As most of you know, over the years we have developed a very close and rewarding working relationship with Dennis Murphy. Dennis is a truly gifted and talented crossover artist. While many may possess similar technical skills, Dennis combines those skills with a keen sense of hearing developed over the years as a practicing symphonic musician. He simply knows how things should sound.
Starting with the first pair of Ellis 1801's I built, I have had an opportunity to build many speaker designs with Dennis Murphy crossovers. And I have never heard one that wasn't right on the money. So when Dennis recently asked if we would like to bring one of his personal designs to market, we obviously said yes.
But before I describe the speaker in detail, I need to ask for your help. In one email, Dennis referred to the speaker as "George." I told him that simply wouldn't do. It needed a name that instilled confidence and perhaps pointed toward one or more of its more significant attributes.
So I'm starting this thread to get some input as to what this speaker might be called. Any and all ideas for a name are welcome. If we happen to select a name you submitted, I can guarantee you won't get rich. But you will certainly feel a sense of pride, knowing you contributed to the success of a great Dennis Murphy speaker design.
Here are some details...
"The speaker" is an MTM design using a MLQW Transmission Line cabinet based on the pioneering work of Martin King. This transmission line cabinet allows the floor-standing speaker to exhibit greater bass extension than a ported design would normally allow.
This design is the end result of a year-long project to develop a very affordable (under $1500) speaker that
- 1) is wide range, with useful bass response to at least 40 Hz;
- 2) has a small enough footprint to allow cabinet dimensions with high SAF; and,
- 3) is sensitive enough to be compatible with a wide range of amplifiers.
Traditional 3-ways would almost certainly fail at least one of the last two requirements. Traditional 2-way bookshelf designs would require a large woofer that might not produce the best possible performance in the upper midrange, and would also require stand-mounting (low SAF).
The solution was to use two high quality 5" drivers optimally suited to Martin King's MLQW transmission line cabinet design, mated to a high quality tweeter.
The Seas CA15 woofers were an obvious choice to perform bass duties, due to their appropriate electrical and mechanical parameters and extremely smooth and extended response at higher frequencies.
The Hiquphon 0W2, which is a more sensitive version of the 0W1 used in Dennis' CA0W1 2-way design, was perfectly suited for the design, since it is sensitive enough to keep up with twin CA15 woofers and provides almost ruler-flat response and extremely broad dispersion. In addition, this tweeter is rugged enough to allow a fairly low crossover frequency with room to spare.
Since the 0W2 is so expensive, an alternative crossover was also developed using the Vifa dx19 3/4" tweeter. Although this unit is not quite as smooth as the 0W2, it too can operate safely at low crossover frequencies and sounds very much like the 0W2.
In either configuration, the sensitivity of the MTM is conservatively rated at 88 dB, and can play a 38 Hz tone at high enough drive levels to set off rattles from loose objects in a typical room.
Here is a picture of the basic design in a prototype cabinet...
The MLQW transmission line cabinets are a sleek 8" wide, 11.25" deep and 44.5" tall (not counting plinths and spikes).
Here is a frequency response plot showing its near ruler-flat response...
Many speaker companies publish FR plots that are 15-degrees off-axis. Here's one that shows the designs response at 60 degrees off-axis!
Here's an impedance plot...
And a reverse null simulation...
While the final details have not been worked out, in order to keep the costs to an absolute minimum, cabinets will be available in three or four standard finishes (piano black most likely being one of them).
When the details are finalized, pre-orders will be accepted.
Thanks, in advance, for any name ideas you may have.
- Jim
