Selected Comparisons
I have enjoyed the AL4.4 and Pd4.4 with all the sources mentioned thus far in this review, as well as those not mentioned.
But since no IEMs in the comparison are particularly hard to drive, I decided to compare them mostly using the iBasso DC-Elite for its highly detailed sound at medium-to-moderately loud volumes.
SIVGA Nightingale PRO
Technical & Design
The Nightingale PRO features a newly designed planar driver with an ultra-thin composite diaphragm structure, paired with a freshly developed 0.008 mm composite diaphragm and a 0.006 mm aluminum ribbon conductor. It is rated at 16 Ω impedance, with an SPL of 107 dB/mW @ 1kHz.
It features aircraft-grade aluminum and magnesium shells machined via 5-axis CNC and a very effective pressure-release system that prevents pressure buildup in the ear canal, which can cause headache, nausea, and ear pain during walking and running.
The Nightingale PRO combines perfectly machined metal parts with a wooden faceplate cover, mixing dark and silver tones with brown wood to suggest an advanced design with a natural feel.
It also has a turbine-shaped metal nozzle cover with a small vent hole near it, which serves as the pressure relief. There is another vent hole near the faceplate and the QDC-style 2-pin connector.
Performance
The Nightingale PRO uses a modern variant of the traditional planar IEM driver with stronger magnets and a thinner diaphragm.
It has the advantages of traditional planars, such as fast transients, extended treble response, high resolution, and very detailed sound. In comparison, AL4.4 and Pd4.4 sound different due to the newly designed 13mm full-range annular planar unit.
The AL4.4 and Pd4.4 sound more like typical single DD IEMs, with a neutral sound and not-so-resolving treble. On the other hand, the AL4.4 and Pd4.4 have a more balanced sound and don’t have the thin note weight and bright upper treble of the Nightingale PRO.
The Nightingale PRO has a more spacious but somewhat artificially big stage. It seems like everything I listen to with the Nightingale PRO has a bigger soundstage than it should, while with the AL4.4 and Pd4.4, the stage size is more accurate.
The Nightingale PRO, AL4.4, and Pd4.4 have no issues drawing power from the source and go very loud without distortion or compression.
ddHiFi Memory E13P
Technical & Design
The Memory features a 13mm ultra-linear planar driver developed by MOONDROP. This new 13mm planar driver has the strength of both dynamic and planar drivers, with 10x the electroacoustic efficiency compared to traditional planar drivers.
The Memory uses the CS43198 DAC chip to convert digital audio signals to analog; it accepts PCM and DSD signals.
In-line control is built into the cable, with a built-in mic for Calls, recording, and music play/pause. This feature has its own wire, so the left and right audio signals are not interrupted with additional solder connections.
An effective pressure-relief system is employed to prevent air from building up in the ear canal, which can cause discomfort, nausea, and headache in some people.
I like the semi-in-ear design, especially the flying saucer-shaped driver shell with the ten vent holes on the side, which also looks like viewing windows for a flying saucer.
A nozzle protrudes from the front end of the shell, and a post-shaped cable port is connected at the rear.
The Memory’s cable shares a very similar design to the ddHiFi M198C and the M130B Coffee Cable; the differences include color, wire composition, electronics, and the 2-pin connectors.
Otherwise, the design is very similar. Unfortunately, Memory’s cable isn’t removable.
Performance
Despite having a built-in USB-C DAC amplifier plug, Memory E13P sounds very similar to both the AL4.4 and Pd4.4, as it doesn’t seem to apply any digital signal processing with the built-in DAC amplifier.
The Memory E13P has a very neutral sound with a flat frequency response, with no boost in the bass, midrange, or treble.
As with the AL4.4 and Pd4.4, Memory also has a somewhat monitoring-style sound signature that sometimes sounds dull, especially at lower listening volumes.
When it comes to soundstaging, they are not too different; due to the better amplification I use with the AL4.4 and Pd4.4, they have a distinct advantage over the Memory E13P. But generally, they are about the same in staging.
At medium to low volume, they have the same dynamic performance, with similar liveliness and energy levels, but at higher volumes, the AL4.4 and Pd4.4’s ability to use a more powerful amplifier gives them an advantage in dynamics and maximum loudness.
HIDIZS MP145 Pro
Technical & Design
The MP145 PRO offers features similar to the original MP145, with improved performance.
The 7 + 7 magnet array is improved to a 1 Tesla Fully Symmetrical Magnetic Circuit, delivering 40% more magnetic flux for clearer sound, a more stable magnetic field, and greater efficiency. The MP145 PRO has an impedance of 30Ω and a sensitivity of 104 dB.
The planar diaphragm itself is also improved through even more precise manufacturing and a 30% increase in the copper trace, which increases detail, response speed, and dynamic range.
Pneumatic Sound Tuning Filters nozzles are replaceable to customize the sound according to the listener’s preference.
The MP145 PRO features an effective ear-canal pressure-relief system. This prevents pressure from building up in the ear canal, which can cause pain, nausea, and headache.
The MP145 PRO has a whale-inspired design; the faceplate resembles a whale’s tail fins. The internal design features hidden ventilation ports on the whale-tail fin faceplate. When viewed from the side, two slot-type vents are on the opposing sides.
The aluminum alloy shell is on the big side; fortunately, it is not too heavy. At 10.2 grams each (measured), it falls within the norm for IEM weight.
Performance
The MP145 PRO is another planar IEM that uses a newer variant of the traditional planar IEM driver with its newly developed motor and diaphragm that eliminate the traditional planar timbre coloration.
The MP145 PRO has a near-neutral and natural sound that combines the single-DD IEM’s natural sound with the planar IEM’s high resolution, detail, and air.
Even so, when compared, the AL4.4 and Pd4.4 sound even more neutral but not necessarily natural. While the AL4.4 and Pd4.4 sound more accurate objectively, with their flat perceived frequency response and monitoring-like sound signature.
The MP145 PRO has a more natural sound with slightly boosted midbass, a slightly relaxed midrange, and a very extended, airy treble.
Not only that, but the MP145 also has a more natural soundscape and a bigger, more immersive soundstage; in comparison, the AL4.4 and Pd4.4 sound like you are in the recording studio at times.
I also find the MP145 PRO more lively and dynamic-sounding across low to high volumes. However, the AL4.4 and Pd4.4 can go just as loud and almost as cleanly as the MP145 PRO when powered from the source.
My Verdict
Both the Memory AL4.4 and Pd4.4 Retro are good additions to ddHiFi’s growing IEM product line, as they match the aesthetics and design language of other ddHiFi products.
I like the design and lightweight, which make them look fashionable, very comfortable, and highly portable.
I also like the neutral, monitoring-like sound with a flat perceived frequency response that allows every part of the music to be presented equally.
However, the monitoring-like sound could come across as too midrange-centric compared to the audiophile-tuned sets most people in the portable ChiFi community are used to.
For that reason, I would suggest carefully evaluating whether you really like the neutral, monitoring-like sound signature before deciding to get the ddHiFi Memory AL4.4 and Pd4.4 Retro.
ddHiFi Memory AL4.4 & Pd4.4 Retro Technical Specifications
- Driver: 13mm planar magnetic unit
- Headphone Plug: 4.4mm balanced
- Effective Frequency Response: 20Hz–20kHz
- Impedance: 16Ω±15% (@1kHz)
- Sensitivity: 121dB/Vrms (@1kHz)
- Total Harmonic Distortion: ≤0.1% (@1kHz)
- Cable Length: 120cm
- Chassis Material: Pure copper, palladium-plated（4）/AL6063 aviation aluminum, CNC formed（AL4.4）
- Cable: Black-mesh-sheathed 6N OCC（4）/Grey-mesh-sheathed 5N OCC（AL4.4）
- Weight: Approx. 31g（4）/Approx. 25g（AL4.4）
- Nozzle diameter: 6 mm
