Merrill DCA5.5 (Almost) Full Range Driver
I always look forward to evaluating a new speaker. It requires critical listening for extended periods which is something I really I enjoy. The Merrill DCA5.5 is a roughly 5" diameter full range speaker available from diyparadise.com. This driver was recently redesigned and features a much heavier cast frame than it’s’ predecessor.
In theory, full range speakers provide sound that radiates
from one coherent point and avoid the difficulties inherent in a crossover
network. Unfortunately, physics works against the one driver approach; a large
driver that produces deep bass is not well suited to high frequencies and a
small high frequency driver will be subject to high levels of distortion
reproducing very low frequencies. The challenge is working out an acceptable
compromise for both.
driver holds tremendous potential for the do it yourselfer. Be advised that you
are buying a raw driver, not a completed speaker, but it truly is an exceptional
driver. Yeo at diyparadise asked me to design a non-resonant enclosure and keep
it as small as possible with 24" as a maximum height.
The low sensitivity (88dB/W/m) has to be considered when selecting or evaluating amplifiers that will work well with this driver. I evaluated these speakers in three different rooms in my house and used amplifiers from 15 to 110 watts RMS with excellent results.
these drivers really excel is on solo piano music, acoustic music and in their
vocal presentation. Their midrange compares favorably to any speaker I’ve
heard regardless of price or size. I listened to these speakers for over 4
months in the rooms I have described and with a range of program material that
would take 20 pages to list in its entirety. In a brief summary, selections from
k.d. lang Hymns of the 49th
Parallel, Linda Ronstadt Cry Like
a Rainstorm and Howl Like the Wind
Court, Joni Mitchell’s Court
and Spark and Sarah McLachlan U
Want Me 2 were breathtaking in their lush reproduction. Male vocals
were outstanding as well. The Rolling Stones Has
Anyone Seen My Baby? [Bridges to Babylon], as well artists like Neil
Young, Bruce Springsteen, Mott the Hoople, U2, Blues Traveler and many others
were exceptional. Piano tracks form Jim Brickman showcased the attack and decay
properties of the driver.
The biggest shortcoming of the DCA5.5 is the bass response, and again that may be of special interest if you like to experiment with drivers. I believe the bass response could be improved at least somewhat in a horn type enclosure. But ultimately the small physical size and limited excursion would limit its’ performance in a full range speaker. I realize there will be people that disagree, but from my experience, you can’t cheat physics and strong bass requires moving lots of air and a larger driver. When I auditioned the Merrill with tracks from both the Titanic and Master and Commander soundtracks, the lack of the lowest octave was very evident. The performance of the Merrill’s was improved considerable when I turned on the powered subwoofer I have in my main system.
When I compared the Merrill DCA 5.5’s to my two reference speakers, the DCA5.5 had equal or better midrange and high end but lacked the low end. Their low efficiency required also fairly substantial drive power but so do my main speakers. My main loudspeakers are two-way Morel drivers in a sealed enclosure with a similar sensitivity. My secondary system has an 8 inch Dynaudio woofer in a transmission line with an ESS Heil AMT-1 handing the midrange and high end.
My office system has Fostex full range ported speakers. The
Merrill’s were a big upgrade in clarity and attack compared to the Fostex
speakers and the difference in the bass response was not as much compared to my
Since it is after all aimed at the DIY market, it should get a lot of props for the tremendous potential and versatility it provides to a speaker designer.
Marantz CD-63SE CD player
15 inch closed box subwoofer with an active crossover and dedicated 200 watt amplifier was used for some of the listening tests.