Hi-fi loudspeakers or studio monitors: which one for home listening

Studio monitors and hi-fi loudspeakers do the same physical work, turning an electrical signal into sound, but they are made for different rooms and different jobs. This guide explains how each is used and what to check before you choose for a home listening room. The examples come from the specifications of the Demograf Audio loudspeakers.

Two tools for two jobs

A studio monitor is generally described as a working tool: it lets a recording or mixing engineer hear what is on a recording, faults included, so that decisions about the mix can be made. Its job is to report, not to please. A home hi-fi loudspeaker plays finished recordings for someone who sits down to listen, often for a whole evening, in a room furnished for living rather than for work.

The two aims overlap more than the labels suggest. An accurate loudspeaker is useful at home too, because it lets you hear the differences between recordings instead of making them all sound alike. The question for a home buyer is whether that accuracy comes with a sound you can live with for hours.

The Demograf Audio catalogue puts this point in its description of Cassandra MkII: "a floorstanding loudspeaker with a monitor’s precision: it shows what is on the recording without sounding cold or becoming tiring." Its catalogue entry names studio monitors as its point of comparison. So when you read "monitor" in a hi-fi description, read it as a statement about precision, not as advice to bring studio equipment home.

How each is used: active or passive, near or far

Many studio monitors are active: the amplifiers are built into the cabinet, and the monitor takes a line-level signal straight from an audio interface or a mixing desk. Many are also designed for near-field listening: they stand on a desk or on stands close to the listener, so that the direct sound reaches the ear well before the reflections from the room.

A passive loudspeaker has no amplifier inside. It is driven by a separate amplifier through loudspeaker cables, which leaves you free to choose that amplifier. For an owner of a tube amplifier this is usually the point: amplifier and loudspeaker are chosen as a pair. Orpheus, Perseus MkII and Cassandra MkII are loudspeakers of this kind, driven by your own amplifier.

The two electrostatic models sit between the two worlds. Menelaus and Atreus are offered in a passive version, driven by your amplifier, and in an active version with built-in Class D amplification. Class D is a switching amplifier design, commonly described as efficient. In both versions the 5,000 V bias supply runs from the mains, so each needs a mains connection: "100 / 120 / 230 V — set at order time, plug to match (NEMA, Schuko, BS 1363 / type G)".

Menelaus lists RCA / speaker binding posts as inputs, with 10 kΩ input impedance. Input impedance is the load an input presents to the equipment that feeds it. The Zeus subwoofer is also passive or active, with a Class A / Class D amplifier optional, and has RCA / speaker binding posts with a 10 kΩ input impedance. In Class A, the output devices conduct over the whole waveform.

Sensitivity: how much amplifier you need

Sensitivity is the sound level a loudspeaker produces from 1 W of input, measured at 1 m, in decibels (dB). It decides how much amplifier power you need for a given volume. The Demograf Audio FAQ gives the arithmetic: every 10 dB of sensitivity is worth ten times the power, so 2 W into a 98 dB loudspeaker plays as loud as 20 W into an 88 dB one.

As rough guides for a medium room, the FAQ gives:

• loudspeakers of about 98 dB (1 W / 1 m) and above for a 2 W amplifier in a room of 20–30 m² at normal listening levels;
• loudspeakers from about 93 dB for a 300B amplifier such as Atlas (5 W);
• loudspeakers from about 88 dB for the 15–25 W of the transmitting triodes in Endymion or Ether.

The Demograf Audio loudspeakers, side by side:

Power handling is the power a loudspeaker is rated to accept; it says nothing about how much it needs. The sensitivity of Perseus MkII is given as a range rather than one figure, so ask which value applies to the driver and configuration you order.

With an active studio monitor, sensitivity matters less to the buyer, because its maker has already chosen the amplifier for the drivers. With a passive loudspeaker it is the first figure to read. At 85–86 dB, the passive versions of Menelaus and Atreus sit below the 88 dB mark of the FAQ guide, so they ask for more power than a 2 W or 5 W triode amplifier can give; the active version carries its own amplification.

Impedance: what the amplifier sees

Impedance, in ohms (Ω), is the electrical load a loudspeaker presents to the amplifier. It changes with frequency, so a single figure is a summary. Orpheus is rated at 8 Ω, Perseus MkII at 6 Ω / 8 Ω and Cassandra MkII at 10–14 Ω.

For low-power amplifiers, the FAQ notes that a high, flat impedance curve and a simple crossover, or none, help. A crossover is the filter that sends each frequency range to the driver meant for it. Cassandra MkII has one crossover point, 3.5 kHz (2nd Order Filters). Perseus MkII is built around a single full-range driver, one that covers the range on its own, with an optional additional driver for a 3-way version.

Menelaus and Atreus are a different load: 2–4 Ω (drops to about 1 Ω at 20 kHz). At the same volume, a lower impedance draws more current from the amplifier. If you choose the passive version, ask the maker of your amplifier whether it is comfortable with a load this low before you connect it. In the active version the built-in Class D amplification drives the panels.

Drivers and cabinets

A driver is the unit that actually moves the air. The Demograf Audio range uses three kinds.

Cone drivers. Orpheus has drivers in three sections (LF / MF / HF); in its top configuration the crossover is listed as "LF driver with iron core inductor; MF driver with large capacitor; HF driver with small capacitor". Cassandra MkII pairs a low/mid driver with a paper cone and a cobalt magnet with a horn-loaded high-efficiency tweeter. In the catalogue's words, the tweeter and the stepped-forward woofer "are aligned in time, which keeps the image precise and three-dimensional."

Field-coil drivers. Perseus MkII uses a field-coil full-range driver, and Zeus a 15″ (larger on request) driver with a field-coil (electromagnet) motor. A field-coil driver uses an electromagnet, powered from a supply, in place of the permanent magnet of a conventional driver.

Electrostatic panels. An electrostatic loudspeaker moves a thin, light diaphragm held between two perforated plates, the stators; a high bias voltage charges the diaphragm, and the music signal on the stators moves it. Menelaus uses electrostatic panels for the HF/MF range (600 Hz – 20 kHz) and a 12–15 inch Demograf Audio Subwoofer for 10 Hz – 600 Hz. Atreus adds an MF/LF electrostatic section covering 20 Hz – 1,000 Hz to its HF/MF panels (600 Hz – 20 kHz), and weighs ~60 kg (including 50 kg steel stators).

The cabinet shapes the bass. Orpheus can be built as Aperiodic Enclosure / Open Baffle / Sealed Box / Labyrinth / Bass Reflex; Perseus MkII offers Aperiodic Enclosure (Acoustic Resistive Matrix) / Open Baffle / Sealed Box / Transmission Line / Bass Reflex; Cassandra MkII is a rear-ported bass reflex; Zeus has an acoustic resistance panel (aperiodic) as standard. In plain words: a sealed box is closed; a bass reflex adds a port, a tuned opening that reinforces the bass; an open baffle has no box at all; an aperiodic enclosure vents through a damping resistance instead of a tuned port; a labyrinth or transmission line guides the rear sound along a long folded path inside the cabinet.

Placement and room size

A near-field monitor is placed so that you hear it before you hear the room. In a home listening room you usually sit farther away, and the room becomes part of the sound: walls, floor and furnishings add reflections and shape the bass. That is why placement and room size belong on the shopping list.

Orpheus, Perseus MkII, Cassandra MkII and Zeus are listed as floor-standing. Plan for their size and weight: Orpheus measures 900 × 700 × 1500 mm and Perseus MkII 500 × 400 × 1300 mm (W × D × H), both From 50 kg per speaker. Zeus measures 450 × 450 × 450 mm, From 12 kg. Because Cassandra MkII has its port at the rear, it commonly needs some space from the wall behind it, where the port output and the wall interact.

The electrostatic models state a room size: Minimum 20–25 m². The Menelaus panels measure 180 × 15 × 5 cm (Straight Shape), with a 450 × 450 × 450 mm subwoofer; the Atreus sections measure 180 × 60 × 15 cm and 100 × 50 × 10 cm (Vertically Curved). An open-baffle panel radiates to the rear as well as to the front, so the distance from the wall behind it matters.

Which piece fits

• A 2 W single-ended triode amplifier, such as Solaria or Eurybia: Orpheus is rated at 103 dB (1 W / 1 m) and 8 Ω, the pairing the FAQ itself points to.
• A 300B amplifier such as Atlas (5 W), or if you want a monitor’s precision at home: Cassandra MkII at 95 dB (1 W / 1 m) and 10–14 Ω, with minimum amplification From 3 W (well suited to tube amplifiers). Perseus MkII, at 93–102 dB (1 W / 1 m) with its field-coil full-range driver, is the other one to discuss.
• Electrostatic panels in a room of at least 20–25 m²: Menelaus or Atreus, either in the active version or in the passive one with an amplifier whose maker confirms it is comfortable with a 2–4 Ω load that drops to about 1 Ω at 20 kHz.
• Deeper bass under any of them: the Zeus subwoofer, 10 Hz – 300 Hz, passive or active.

If your work is mixing, a studio monitor is the tool built for it. If you are choosing for listening at home, start from your amplifier and your room. Write to us with the size of the room, the amplifier you own or plan, and the music you play; the steps are on How to order.