A dual-channel digital parametric EQ with a 340 ms delay line on each side — and a nameplate that sends collectors on a confusing chase.
Overview
The DN-4000 is one of those pieces where the badge on the front and the badge on the manual don't quite agree, and anyone shopping for one needs to understand that before money changes hands. The document trail for this unit consistently describes a dual-channel programmable parametric equaliser — five fully parametric bands per channel, high- and low-frequency shelving filters, plus high-pass and low-pass filters, with dedicated switches for direct access to every EQ filter. That much is repeated across the period documentation. What is not repeated is the maker's name: the source material for this model carries Klark Teknik and Mark IV Pro Audio Group branding, not Denon. Collectors should treat the "Denon DN-4000" attribution as unresolved and verify the nameplate on any actual unit before committing.
Setting the identity question aside, the feature set is genuinely ambitious for a rack equaliser of its generation. Each channel carries a delay line with a maximum delay time of 340 ms — the kind of number that matters if you're time-aligning a delay stack or chasing a speaker placement compromise you can't fix with a saw. The front panel runs on rotary controls for frequency, Q, and level, which the documentation frames as the fast, simple way to set up a filter, aided by a large backlit LCD that can display both channels simultaneously. Anyone who has dialled in a parametric by feel on tiny pots knows why the rotary-plus-display approach is the humane one.
The processing engine is digital, and the documentation specifies advanced 20-bit AD/DA conversion, with the dynamic range claimed to be comparable to the best analogue equalisers. Treat that as the manufacturer's line rather than a measured verdict — but the 20-bit figure is the number to look for on the box. Mix (December 1996, p.141) covered the unit at a list price of $4,600 and recorded 18-bit converters alongside the five parametric bands, the shelving and pass filters, the 340 ms delay, the backlit LCD, and 30 nonvolatile EQ memories. That converter discrepancy — 18-bit in the review, 20-bit in the promotional copy — is worth flagging; the safest reading is that the shipping spec is 20-bit and the review captured an earlier or differently configured figure. Neither number should be quoted as gospel without checking the specific unit's serial and manual.
System integration is where this thing earns its rack space. MIDI and remote interface ports allow control of up to 16 DN-4000 units from a single master — a serious number for anyone building a multi-zone or multi-cabinet install where you don't want to walk the room with a flashlight and a tweaker. An optional AES/EBU digital audio interface extends it into all-digital chains. The 30 nonvolatile memories mean your carefully tuned room curve survives a power cycle, which sounds trivial until you've lost one.
The delay-and-EQ pairing is the pitch the literature leans on, and it's a fair one: "Delay with EQ, or EQ with delay?" the copy asks, and the answer is that both live in the same box with independent control per channel. For a sound system designer working difficult rooms — the documentation specifically calls out rooms with a characteristic honk or resonance — the parametric bands let you track a problem frequency and its Q precisely rather than hacking at it with a graphic. The same copy warns that high Q with a peaking response will ring at the centre frequency, which is the honest caveat every parametric user learns the hard way.
That's the shape of the DN-4000: a capable, memory-rich, remotely controllable dual parametric with a useful delay line, sold at a price that put it firmly in professional-install territory. The open questions — production years, weight, dimensions, current market values, common failure modes — simply aren't documented in the available material, and this page won't invent them. What a buyer can act on is the feature set, the converter question, and the nameplate question. Verify all three in person.
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