I had a chance to move on a pair of Dahlquist DQM-9 monitors recently, so I took advantage and have them in my listening room now.
They came about locally, with woofer surrounds that were shot, and cabinets and grilles needing some TLC. The tops of the cabinets have some minor flaws. The veneered wood sides of the cabinets are in decent condition, although one of the sides has some of the stain missing in tiny spots lower down; it really is not that noticeable unless you are close. The one grille frame was cracked on opposite corners and I have it perched on the mounting pegs for now. It will need angle brackets and gluing to bring it back. The aluminum trim around the drivers needs cleaning and polishing but behind the grilles, only the outlines are noticeable.
The construction is all Magnat (Germany) drivers; I’ve even read rumors that the entire systems were made by Magnat and branded Dahlquist. Nothing officially verified though, but I have seen entire systems made by Magnat from the same era (Magnat All-Ribbon series, etc.) that have similar cabinet construction, with the same “velvet” front baffle material. The DQM-9 came in two versions–the larger one that I own, and a slightly scaled down “Compact” version with an 8″ woofer, which had a butyl rubber surround. The woofer in the DQM-9 is a 10″ with foam surround. Midrange, 5″ with rubber surround. Tweeter is a treated fabric dome type. Cabinet is a reflex design with dual ports facing rearward.
List price on the DQM-9, circa 1982, was $1200 for the pair, climbing to $1400 for the pair by the mid 80s. These were, therefore, a couple of notches above the speakers I’ve had in recent years (the Grafyx, and the Boston A-150s).
When local audio emporium Absolute Sound carried the DQM series in the 1980s, I remember them having a somewhat “chesty” resonance to the mid-bass that wasn’t too pleasant. When I removed the woofers to redo the surrounds, I noticed that the bottom half of each cabinet had no insulation whatsoever. The top half uses fiberglass.
I ended up putting some polyester fiberfill into the bottom halves of the cabinets before reinstalling the woofers. I have not heard that resonance at all. I thought maybe there was no internal bracing, but there was–a brace runs between the two sidewalls against the rear panel of the cabinet, which is the dividing line between the top and bottom halves. I had considered using Dynamat inside as well, but it won’t be needed. It is interesting to note that the left and right sides of the cabinet are a double thickness of MDF, so they are sturdy to begin with.
Beyond doing a full cosmetic restoration, one tweak or improvement I thought of making would be to redo the crossovers with new components. However, the crossover uses more expensive film capacitors, so they are not prone to age like electrolytics. I would possibly redo the cheap hookup wire with some OFC copper wiring. An interesting design feature is that the crossover is split across three modules inside the bottom half of the cabinet.
The sound? Quite good, and clearly a step above both the Grafyx speakers I have had for decades, and the Boston A-150s I had for several years. Imaging is rock solid left to right, yet I do not yet hear much in the way of depth or a soundstage spread beyond the speakers. I have not tinkered with positioning much yet. I settled for now on having them halfway between toed in directly at the listening seat and facing straight ahead. My stands tilt them back slightly, and I am thinking to have them tilt just a little more forward. I also need to spike the stands to the floor (there is a concrete slab beneath the carpeting and padding), and the speakers to the stands. I am even at the point of possibly making some stands for these.
Tonally the bass is deceptive–while it does not seem as deep the Grafyx at lower volume, they really fill out nicely when the volume is kicked up. It takes a little volume to fully wake them up. In fact, they may go a bit deeper; they grab the 32Hz notes easily when called upon, and orchestral crescendos are taken in stride, with no stress or strain. The highs are not completely as smooth as I’d have thought, but that may again be due to the aged crossovers; what is there, however, is not at all bright, and that lower treble/upper midrange glare I had from the Philips tweeters in the Grafyx is all but gone now. These are easy to listen to for hours, and while I haven’t tried them fully with rock music (which I don’t listen to much anymore), it holds up well with large-scale classical, acoustic jazz, vocals and even electronic jazz.
These will be in my system until the Martin Logan refurb project is completed.