Compare
Same room,
same volume.
We compare in one room, at one matched volume, and we write the difference in words. The tables use the same figures as the product pages.
Oto Audio — compare
How we listen
Volume-matched, notes in words.
Comparisons are made in the listening room at Pelgrimsgang 14. The room is 28 m², with treated walls. We play the same tracks for each piece and match the volume before anyone comments. Notes are written in words, not as a score. You can put up to three headphones, or two speaker pairs, on the table in a 60-minute hour.
The three tables below use one set of figures: the headphones H1, H2 and P7; the amplifiers A10 and A40 with the D2 DAC; the speakers S5 and S8. Prices are the shop prices. If a cell is a dash, that product does not have that rating. The D2 is a DAC, so its power cell is blank.
Headphones
Three headphones,
side by side.
Oto H1 Open, Oto H2 Closed and Oto P7 Planar, played at the same volume on the same tracks.
| Specification |  Oto H1 Open€349 |  Oto H2 Closed€299 |  Oto P7 Planar€890 |
|---|---|---|---|
| Type | open-back dynamic | closed-back dynamic | open-back planar |
| Driver | 50 mm | 40 mm | 90 mm planar |
| Impedance | 32 Ω | 24 Ω | 18 Ω |
| Weight | 290 g | 275 g | 420 g |
| Sound | airy, wide, light bass | close, warm, firm bass | even, detailed, deep bass |
| Leaks sound | yes | very little | yes |
| Best with | any phone or DAC | phone, night, travel | A10 or A40 |
| Price | €349 | €299 | €890 |
Oto H1 Open€349
- Type
- open-back dynamic
- Driver
- 50 mm
- Impedance
- 32 Ω
- Weight
- 290 g
- Sound
- airy, wide, light bass
- Leaks sound
- yes
- Best with
- any phone or DAC
Oto H2 Closed€299
- Type
- closed-back dynamic
- Driver
- 40 mm
- Impedance
- 24 Ω
- Weight
- 275 g
- Sound
- close, warm, firm bass
- Leaks sound
- very little
- Best with
- phone, night, travel
Oto P7 Planar€890
- Type
- open-back planar
- Driver
- 90 mm planar
- Impedance
- 18 Ω
- Weight
- 420 g
- Sound
- even, detailed, deep bass
- Leaks sound
- yes
- Best with
- A10 or A40
Choose the H2 when the sound has to stay with you: night, travel, a phone in a shared room. It leaks very little, and the character is close and warm, with firm bass. Choose the H1 when you want air and width and light bass, and a leak into the room is acceptable. Any phone or DAC is enough.
Choose the P7 when you want an even, detailed sound and deep bass, and you can use the A10 or the A40. It is the heaviest of the three at 420 g, and it is open-back, so it leaks. Hearing all three at the same volume is more useful than ranking the ohms.
Amplifiers and DAC
The amplifiers
and the DAC.
Oto A10 Desktop Amplifier, Oto A40 Integrated Amplifier and Oto D2 USB DAC.
| Specification |  Oto A10€420 |  Oto A40€1,290 |  Oto D2€260 |
|---|---|---|---|
| Role | headphone amplifier | integrated amplifier | USB DAC |
| Power | 1.2 W into 32 Ω | 2 × 40 W into 8 Ω | — |
| Inputs | 2 analogue | 3 analogue + phono | USB-C, optical |
| Outputs | 6.35 mm + 4.4 mm | speakers + 6.35 mm | RCA + 3.5 mm |
| Sound | quiet, controlled | relaxed, full | neutral, low noise |
| Best with | P7, H1 | S5, S8 | A10, A40 |
| Price | €420 | €1,290 | €260 |
Oto A10€420
- Role
- headphone amplifier
- Power
- 1.2 W into 32 Ω
- Inputs
- 2 analogue
- Outputs
- 6.35 mm + 4.4 mm
- Sound
- quiet, controlled
- Best with
- P7, H1
Oto A40€1,290
- Role
- integrated amplifier
- Power
- 2 × 40 W into 8 Ω
- Inputs
- 3 analogue + phono
- Outputs
- speakers + 6.35 mm
- Sound
- relaxed, full
- Best with
- S5, S8
Oto D2€260
- Role
- USB DAC
- Power
- —
- Inputs
- USB-C, optical
- Outputs
- RCA + 3.5 mm
- Sound
- neutral, low noise
- Best with
- A10, A40
Choose the A10 for headphones at a desk. It is the one we describe as Class A, with two outputs, and it is the partner for the P7 planar and the H1. The background is quiet and the drive is controlled. Power is 1.2 W into 32 Ω, which is the figure to read if you are coming from the P7 at 18 Ω or the H1 at 32 Ω.
Choose the A40 when the system includes speakers. It is relaxed and full, 2 × 40 W into 8 Ω, with a headphone socket still there. The S5 and the S8 are the pairs we use with it. Choose the D2 when the source is a computer or an optical output and you want a neutral, low-noise feed into the A10 or the A40.
Speakers
Two speaker
pairs.
Oto S5 Bookshelf Speakers and Oto S8 Floorstanding Speakers, each sold as a pair.
| Specification |  Oto S5€780 |  Oto S8€2,150 |
|---|---|---|
| Type | 2-way bookshelf | 3-way floorstanding |
| Drivers | 25 mm + 150 mm | 25 mm + 130 mm + 2 × 165 mm |
| Sensitivity | 86 dB | 90 dB |
| Room size | 10–20 m² | 20–35 m² |
| Sound | open midrange | full range, easy bass |
| Best with | A40 | A40 |
| Price | €780 | €2,150 |
Oto S5€780
- Type
- 2-way bookshelf
- Drivers
- 25 mm + 150 mm
- Sensitivity
- 86 dB
- Room size
- 10–20 m²
- Sound
- open midrange
- Best with
- A40
Oto S8€2,150
- Type
- 3-way floorstanding
- Drivers
- 25 mm + 130 mm + 2 × 165 mm
- Sensitivity
- 90 dB
- Room size
- 20–35 m²
- Sound
- full range, easy bass
- Best with
- A40
Choose the S5 for a small room. The open midrange is what we listen for, and the stated range is 10–20 m². A study of about 14 m² sits inside that span. Sensitivity is 86 dB. The pair is at its best with the A40.
Choose the S8 when the room is 20–35 m² and you want full range and easy bass. Sensitivity is 90 dB. It is also at its best with the A40. The S8 ships by courier at the same rates as the rest of the range: free in the EU over €150, otherwise €9. If you want both pairs in one visit, the hour allows two speaker pairs, volume-matched, on the same tracks.
Listening room
An hour in the room is free: same tracks, volume matched, up to three headphones or two speaker pairs.