Audio T Verdict
The PMC Active twenty5.24i is the largest and most capable two-way model in PMC's Active twenty5i range. It combines the scale and low-frequency authority of a substantial floorstanding speaker with amplification and crossover electronics developed specifically for its drive units.
Each cabinet contains a dedicated 100W amplifier for the tweeter and another 100W amplifier for the 170mm midrange and bass driver. Dividing the signal before amplification allows each amplifier to concentrate on the frequencies required by the driver it controls.
The 3m Advanced Transmission Line and Laminair vent help the slender cabinet reach a published 27Hz, giving it the depth and room-filling ability required for medium-to-large listening spaces.
Add a suitable pre-amplifier or network streamer with volume-controlled analogue outputs and there is no need for a separate integrated or power amplifier. It is an elegant route to a genuinely high-performance system with fewer boxes and no compromise on scale.
PMC Active twenty5.24i Floorstanding Speakers
The Active twenty5.24i is a pair of two-way active floorstanding speakers with amplification and a model-specific analogue crossover built into each cabinet.
Its principal features include:
- HF 100W RMS and LF 100W RMS amplification in each speaker
- Model-specific analogue active crossover
- Balanced analogue XLR input on each speaker
- Unbalanced analogue RCA input on each speaker
- Selectable low and high input sensitivity
- 170mm long-throw g-weave midrange and bass driver
- 19mm SONOMEX fabric soft-dome tweeter
- PMC Advanced Transmission Line bass loading
- 3m effective ATL length
- Front-mounted Laminair vent
- Diamond Black, Oak and Walnut finishes
Active Amplification Designed for the Speaker
In a conventional passive system, an external amplifier sends a full-range amplified signal through speaker cable to the crossover inside each loudspeaker.
The Active twenty5.24i divides the incoming line-level signal before power amplification. The high-frequency signal feeds the tweeter amplifier, while the lower frequencies feed the amplifier connected directly to the 170mm driver.
This arrangement provides:
- A dedicated amplifier for each drive unit
- Direct amplifier-to-driver connections
- No passive crossover between the amplifiers and drivers
- Amplifier gain and crossover behaviour selected by PMC
- A simpler system without a separate power amplifier
200W of Amplification per Cabinet
Each speaker contains:
- High-frequency amplifier: 100W RMS
- Midrange and bass amplifier: 100W RMS
The stereo pair therefore contains four dedicated amplifier channels.
This should not be interpreted in exactly the same way as a single conventional 200W amplifier driving a passive speaker. Each internal amplifier handles only the frequency range assigned to its connected drive unit.
Analogue Active Crossover
The model-specific active crossover divides the incoming analogue signal at approximately 1.9kHz before it reaches the power amplifiers.
Removing the passive crossover from between the amplifiers and drive units allows the internal electronics to maintain direct electrical control over each driver.
The speakers accept analogue signals only. Digital conversion and network streaming must be provided by the connected source component.
170mm g-weave Midrange and Bass Driver
The Active twenty5.24i uses a 170mm long-throw g-weave cone in a rigid cast-alloy chassis.
The larger driver provides greater radiating area than the 140mm unit used in the Active twenty5.23i, helping the 24i deliver greater scale, dynamic ability and low-frequency output.
It reproduces bass and midrange information including vocals, guitars, piano, drums, bass instruments and the lower frequencies of orchestral and electronic recordings.
19mm SONOMEX Soft-Dome Tweeter
High frequencies are reproduced by a PMC/SEAS 19mm SONOMEX fabric soft-dome tweeter.
The tweeter is ferrofluid cooled and uses a 34mm surround with a dispersion grille, helping it provide detailed and consistent high-frequency coverage across the listening area.
PMC Advanced Transmission Line
The Active twenty5.24i uses PMC's Advanced Transmission Line, commonly abbreviated to ATL.
Energy generated by the rear of the 170mm driver enters a folded and acoustically damped internal line measuring approximately 3 metres.
The damping is designed to absorb unwanted upper-frequency energy while allowing useful low-frequency output to travel towards the front vent.
PMC uses ATL technology to pursue:
- Deep bass from a relatively slender cabinet
- Controlled low-frequency decay
- Reduced unwanted midrange output from the vent
- Clear separation between bass and midrange information
- A balanced sound at both quiet and higher listening levels
Front-Mounted Laminair Vent
PMC's Laminair vent uses shaped internal vanes to manage the high-speed airflow leaving the transmission line.
The design is intended to reduce turbulence, resistance and unwanted airflow noise while improving bass timing and efficiency.
Its position on the front provides useful flexibility, but distance from walls will still affect bass quantity and definition.
27Hz to 25kHz Frequency Response
PMC specifies a frequency response of 27Hz to 25kHz.
This is the deepest published bass extension in the two-way Active twenty5i range and allows the 24i to reproduce substantial low-frequency information without automatically requiring a subwoofer.
The result heard in the room will also depend on:
- Distance from rear and side walls
- Room dimensions and construction
- Listening position
- Source output level
- Playback volume
- The low-frequency content of the recording
Balanced XLR and Unbalanced RCA Inputs
Each speaker provides:
- One balanced analogue XLR input
- One unbalanced analogue RCA input
A left-channel signal cable connects to the left speaker and a right-channel cable connects to the right speaker.
Balanced XLR may be useful for longer cable runs or installations where rejection of electrical interference is beneficial. RCA provides compatibility with a wide selection of domestic streamers, DACs and pre-amplifiers.
Line-Level Inputs Only
The XLR and RCA connections accept analogue line-level signals.
Do not connect the speaker outputs of an integrated amplifier, stereo receiver or power amplifier. Amplified speaker-level signals could damage the active input electronics.
A Volume-Controlled Source Is Required
The speakers contain amplification but do not provide source selection, streaming or a conventional user volume control.
A suitable partnering component must provide safe volume-controlled analogue outputs, such as:
- A dedicated stereo pre-amplifier
- A network streamer with variable RCA or XLR outputs
- A DAC with a proper pre-amplifier function
- An AV processor with analogue pre-outputs
Do Not Connect an Uncontrolled Fixed Output
A fixed-output CD player, DAC or streamer may send full line level directly to the speakers.
Confirm that the connected component provides a safe, predictable and properly implemented volume control before making the connection.
Selectable Input Sensitivity
A rear-panel sensitivity setting allows the speakers to be matched to different source-output levels.
- Low setting: 1V RMS produces 99dB SPL at 1m
- High setting: 1V RMS produces 109dB SPL at 1m
The lower-sensitivity setting will normally provide more usable volume-control range with sources that have a relatively high analogue output.
The most appropriate setting should be selected during installation, with the source volume initially kept low.
No Built-In Streaming or Digital Inputs
The Active twenty5.24i does not include:
- Wi-Fi or Ethernet
- Bluetooth or AirPlay
- HDMI ARC or eARC
- Optical or coaxial digital inputs
- USB audio
- A built-in network streamer
- A digital-to-analogue converter
- A phono stage
These facilities can be added through the selected streamer, DAC or pre-amplifier.
Streamer and Pre-Amplifier Matching
A network streamer with variable analogue outputs can create a particularly neat and capable system.
Potential partners include the Bluesound NODE ICON, which provides balanced XLR and RCA outputs, or a suitably configured Linn Selekt DSM Classic Hub.
The final choice should be based on sound quality, volume-control performance, source inputs, streaming-service support and system budget.
Two Mains Connections Are Required
Each cabinet contains its own crossover and amplification, so each speaker requires a nearby earthed mains connection.
The electronics support 90–260V mains through an IEC C14 connection.
Allow free airflow around the rear electronics and route signal and mains cables safely without tension or trip hazards.
Placement and Levelling
Begin with the speakers positioned an equal distance from the listening seat and a similar distance from the rear and side walls.
Moving them closer to a wall will normally increase perceived bass weight. Moving them farther into the room may improve low-frequency definition and soundstage depth.
The main cabinet is 192mm wide, increasing to approximately 275mm across the plinth bars. Adjustable spikes add approximately 20mm to the cabinet height.
Use suitable floor-protection cups on hard or delicate flooring and ensure both cabinets are level and stable.
Which Active twenty5i Model?
Choose the Active 23i When
- A slimmer floorstanding cabinet is preferred
- The room is medium sized
- A 140mm driver provides sufficient scale
- 28Hz published bass extension suits the system
- The lighter cabinet is easier to accommodate
Choose the Active 24i When
- The largest two-way Active twenty5i is required
- The room is medium to large
- A 170mm driver is preferred
- Greater scale and dynamic headroom are useful
- The 3m ATL and 27Hz response suit the system
Explore the PMC Active twenty5.23i Floorstanding Speakers to compare the slimmer model.
Key Features
- Largest two-way Active twenty5i model
- Supplied as a stereo pair
- HF 100W RMS per speaker
- LF 100W RMS per speaker
- Four amplifier channels per pair
- Model-specific analogue active crossover
- 1.9kHz crossover frequency
- 170mm g-weave driver
- 19mm SONOMEX soft-dome tweeter
- PMC Advanced Transmission Line
- 3m effective ATL length
- Front-mounted Laminair vent
- 27Hz–25kHz frequency response
- Balanced analogue XLR input
- Unbalanced analogue RCA input
- Selectable input sensitivity
- Input impedance above 14kO
- 90–260V IEC mains input
- Diamond Black, Oak and Walnut finishes
- 20-year registered PMC warranty
Frequently Asked Questions
Are the speakers supplied as a pair?
Yes. The product includes two active floorstanding speakers.
Do I need a separate power amplifier?
No. Each cabinet contains dedicated amplification for its two drive units.
How much amplification is built in?
Each speaker contains one 100W RMS amplifier for the tweeter and one 100W RMS amplifier for the midrange and bass driver.
Do I need a pre-amplifier?
A pre-amplifier, streamer or DAC with safe volume-controlled analogue outputs is required.
Which inputs are included?
Each speaker has one balanced analogue XLR input and one unbalanced analogue RCA input.
Can I connect an amplifier's speaker outputs?
No. The speakers accept line-level analogue signals only.
Do they include streaming, Bluetooth or a DAC?
No. These features must be provided by the connected source component.
Does each speaker need mains power?
Yes. Each cabinet requires its own earthed mains connection.
What is the frequency response?
PMC specifies 27Hz to 25kHz.
What is the effective ATL length?
Approximately 3 metres.
What are the dimensions?
Each cabinet measures approximately 1015 x 192 x 419mm (H x W x D). Allow another 20mm for the spikes, 9mm for the grille and additional rear cable clearance. Overall width is approximately 275mm across the plinth bars.
How much does each speaker weigh?
Approximately 23.15kg.
Which finishes are available?
Diamond Black, Oak and Walnut.
What warranty is available?
PMC offers a 20-year manufacturer warranty when the speakers are registered within 10 days of purchase, subject to its full terms and conditions.
Related PMC Products and Audio T Guides
Why Buy From Audio T?
- PMC Active twenty5.24i demonstrations
- Active twenty5i model comparisons
- Streamer and pre-amplifier matching
- Balanced XLR and RCA comparisons
- Source-output compatibility checks
- Input-sensitivity configuration
- Speaker placement and toe-in advice
- Mains and signal-cable planning
- Floor-spike and levelling setup
- Home demonstrations where available
- Part exchange on suitable existing equipment
- PMC warranty-registration guidance
- Ongoing system and after-sales support
Contact your local Audio T store to arrange a demonstration or discuss streamers, pre-amplifiers, cables and room placement for the PMC Active twenty5.24i.