AKM’s AK449X DAC chip, from 2016 AK4495 has been released for about six years, we have seen AK4495, AK4493, AK4490, AK4497 and other DAC chips appearing on portable players, sound cards, decoders and other devices. The flagship model AK4499 DA was released in December 2018. It was originally high-end models to market at the end of 2019 – early 2020, but due to epidemic, chip shortage, plant fire and its own AK4499 chip positioning caused it. Fortunately, the player, sound card and decoder of AK4499 DAC have appeared in the last 2020. The main significance of AK4499, from the official voice of AKM, except for the digital part of superior performance, it is also the first time to release current output DAC chip for more than ten years, and put I / V outside the DAC chip [voltage type means built-in ” I / V]. From the third party, AKM officially gave an I / V external view that allowed audio performance to make a larger view. So, let’s take a look at the performance of this AKM AK4499 DAC chip for netizens to purchase the SMSL M400.

Double Wood Sanlin S.M.S.L M400 USB External Decoder

Appearance, main function and specifications

Double Wood Sanlin SMSL M400 Decoder is similar to the device that is currently using the AK4499 DAC chip, the price will not be too low, this is the chip positioning and price limit. The M400 is sold at 5,000 yuan. Generally speaking, the configuration is not too high, and the appearance is only the average level of SMSL. As a desktop decoder, you can only say that the real machine looks better than the photo. But the details are not required.

1. Appearance:

The SMSL M400 decoder appearance work and design is very general, the top cover is a black acrylic panel, and the visual effect is good in the new state, but it is difficult to maintain, such as electrostatic ash, fingerprint collection, not wear, and SP400 ear It will not be good with the “suit” stacking effect. The surface process of a black aluminum material in the fuselage is generally, and the assembly accuracy is general. If you are in front of a small desk, you will feel fine. It seems to be small and meticulous on the acoustic cabinet.

The front side of the decoder is left to the left is a color liquid crystal screen, and the normal bright state will display the volume number and the parameters of the input signal, such as the sampling rate of the PCM. In addition, there are some function settings that require it to display. We will talk about the function introduction below. The assembly of this screen has a relatively severe defect, ie its liquid crystal panel directly cards in front of the chassis opening, completely panel, no pre-glass protection. So it is not careful … LCD is broken. Why is it bad? For example, we can add the wire on the back, it is easy to need to top it in front? It’s broken when you are not careful.

On the right side of the front panel is the knob, this knob has a poor sense, and the rotation is loose. The intermediate area is the button and is useful in function settings. The most central has a very small opening, and the red LED work indicates when the machine standby.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

2. Interface:

The SMSL M400 decoder back is a regular input and output interface. In addition to the power interface, the IIS digital signal input of the USB-B interface, the IIS digital signal input of the HDMI interface, the coaxial RCA and the optical fiber are input. In terms of output, there is a pair of RCA LINEOUT and a pair of XLR balance line output. In terms of HDMI IIS input, the official explains the pin definition, there are two specifications available in the software. DSD part, and Flag have custom specifications in software. Unfortunately, we only enjoy the MR1 in our hands to provide HDMI IIS output, but it is not compatible. In addition, there is a small antenna on the back, which is used for Bluetooth signal reception.

3. Main functions:

We simply understand its main functionality through the screen capture of the M400 decoder. As shown, the first behavior input option does not automatically identify, no auto. In addition to several wired inputs mentioned above, it also includes Bluetooth input. Next, several options mainly include specifications and settings for several sets of IIS inputs. In addition, it is also possible to set whether the volume output is adjustable, or the maximum lock. In addition, there is also a PCM digital filter type option for AK4499 DAC, and a combination of DSD filters wide and narrow two sets. In addition, the XLR balance output also takes into account two different approaches, phase differences, and can be switched in software. Overall, it is easy to get started. The only thing to vomit is that if the remote control is not used, after the setting is completed, there is no return button, which can only be hard to automatically jump back to the main interface, and the volume adjustment can be performed, this time is a bit long, about 20 seconds.

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Screenshot of Screen

The design of the remote control seems to be relatively simple, but the volume, input switching and other functional operations are more convenient. Moreover, the official also designed the remote control default anti-aid function, and needs to be operable according to the C key. This feature is good … It is not to understand that it doesn’t understand. In addition, it is worth mentioning that the SP400 ear is used, and the SP400 also has a separate remote control. And it can be on the crosstalk.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

4. Talking about voltage type and current DAC chip:

The voltage output and current output refer to a voltage or a changed current that the DAC chip finally outputs signals in the analog circuit is changed. Obviously, in an audio device, a sound card, a decoder, etc. need to convert the digital signal into an analog signal, and pass the changed voltage to the next level to amplify as predecessors or amplifiers. The current Delta-Sigma DAC or R-2R DAC or D / A circuit in the digital circuit textbook is a current value that converts the number 01 signal into a corresponding change, it needs to do I / V conversion. The so-called voltage type DAC, such as AK4495, AK4493, AK4497, is a built-in I / V circuit. The current type DAC is to allow the I / V portion to be implemented by the chip external circuit.

Common Voltage DACs include Cirrus Logic CS4398, CS43131, and the like. Common current type DACs such as PCM1792, PCM1794, ESS902X PRO series, etc. (ESS partial voltage type DAC seem to also provide current output mode, such as early ES9018k2M?).

5.akm AK4499 DAC:

This DAC chip is the flagship model of AKM, but also the first generation of AK4397 flagship first release current output type DAC. According to the official introduction, there is a built-in D / A channel, and 4 channels can be supported in parallel, and the signal to noise ratio of 140 dB can be reached in this state. That is, if the stereo decoder left, the right channel can be used to reach the indicator. The SMSL M400 is used as a single AK4499, but it can also be done in parallel every two D / A channels [AK4497 for two D / A channels, the official nominal combined mono output is 131dB signal-to-noise ratio].

In terms of specifications, the AK4499 should be different from the AK4497, after all, it has been possible to do the 32bit / 768kHz and DSD512 hardware decoding of the PCM, and the XMOS XU216 with the 16 core can also match it in terms of USB channel. In addition, the M400 decoder also supports MQA decoding, Bluetooth uses a CS8675 chip to support the UAT Bluetooth wireless solution with Haibei music.

In other configurations, such as high-precision clock chips, you can refer to official information. In the most critical AK4499 DAC as a current output type DAC, it is necessary to match the external I / V circuit [generally use the op amplifier chip to complete], the official does not have a detailed introduction, but it is written in the manual to the OPA1612 op amp, but also Not explicit use in I / V or LPF, or elsewhere.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Below us, objective testing

Objective test

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Objective test part, because the SMSL M400 decoder is typical in the output, we have tested RCA LINEOUT and BAL LINEOUT in the USB section. In addition, the LDAC Bluetooth connection is performed, and the LINEOUT RCA is output. Haibei UAT test, it was originally very interested, but the test results were bizarre, for reference only. Actual test, Under the RCA non-balanced output, the maximum output voltage is 2.3vrms, and the balance XLR output is ± 2.3VRMS. The test is based on the first PCM filter option under Sharp.

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Essee Curve @Lineout

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Surveying Curve @BAL

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Noise Distribution @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Noise Distribution @BAL

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Dynamic Range @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Dynamic Range @BAL

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Total Harmony Distortion @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Total Harmony Doss @BAL

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Intermodulation Distortion @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Intermodulation Distortion @BAL

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Curve @Lineout

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Curve @BAL

Test items

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

LO

BAL

Lo96

BAL96

Noise level, DB (a):

-94.9

-95.1

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-116.7

-117.4

Dynamic range, DB (a):

94.9

95.1

116.7

117.4

Total harmonic distortion,%:

0.00053

0.00024

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

0.00031

Intermodulation distortion,%:

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

0.00512

0.00490

0.00088

0.00068

Stereo separation, DB:

-94.8

-110

-115.2

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Test @Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan 96kHz @ lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan DSD @ lineout

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Frequency Analysis @Lineout

There is no problem with objective indicators of the SMSL M400 from objective testing, all aspects are good, of course, all kinds of equipment test indicators in the past AK449X are nice. However, after all, the objective indicators of I / V, M400 are satisfactory. If you are very interested in test results, it is recommended to pay attention to the THD and IMD under 24bit / 96kHz.

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Esternet Curve @ ldac44.1 Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Surplus Curve @ LDAC48 LINEOUT

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Noise Distribution @ ldac44.1 Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Noise Distribution @ ldac48 Lineout

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Dynamic Range @ ldac44.1 Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Dynamic Range @ ldac48 Lineout

Double wood Sanlin S.M.S.L M400 USB external decoder – Total harmonic distortion @ ldac44.1 Lineout

Double wood Sanlin S.M.S.L M400 USB external decoder – Total harmonic distortion @ LDAC48 LINEOUT

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Intermodulation Distortion @ ldac44.1 Lineout

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Intermodulation Distortion @ LDAC48 LINEOUT

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Curve @ LDAC44.1 LINEOUT

Double Wood Sanlin S.M.S.L M400 USB External Decoder

Double Wood Sanlin S.M.S.L M400 USB External Decoder

Double Wood Sanlin S.M.S.L M400 USB External Decoder

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-94.9

0.00053

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Separation Curve @ LDAC48 LINEOUT

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

LDAC test

16/44

24/48

24/96

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Noise level, DB (a):

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-94.9

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-101.6

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-104.1

Dynamic range, DB (a):

94.9

102.5

114.3

Total harmonic distortion,%:

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

0.00057

0.00197

0.00091

Intermodulation distortion,%:

0.00538

0.00256

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

0.00215

Stereo separation, DB:

-94.4

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

-99.2

-99.3

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan @LDAC 44.1

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan @LDAC 48

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan @LDAC 96

The LDAC part is also normal, and it is also stable in close range of use. However, from an objective indicator, about 104dB of the signal to noise ratio under 24bit, it seems to be a slight gap between our usual test platform, should not be the best state of LDAC, but it is not easy to detect.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

The UAT test results of the sea beck are shown in the figure. At present, this result is really a bit difference. As shown in the figure, the frequency scan of 20 Hz-48kHz under 96kHz sample rate is distorted from 14kHz under high sound quality. The higher the frequency, the brightness of the line is significantly increased? That is, the level is significantly increased. In the partial connection quality mode, the situation is even more miserable. Look again, 44.1KHz sampling rate 20Hz-20kHz scan, more strange, watch the waveform, what is this shape? Surprisingly, if we turn off the LDAC in Android settings, the situation will be even more miserable.

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan 44.1KHz@hiby Uat Bluetooth

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan 96kHz @ Hiby Uat Bluetooth

The previous paragraph is a connection priority setting, and the next section is a sound quality.

Double Wood Sanlin S.M.S.L M400 USB External Decoder – Frequency Scan 96kHz @ Hiby Uat Bluetooth LDAC Off

Of course, about the Bluetooth UAT test, considering the various problems such as receiving ends, transmitting ends, and both end software, and cannot be determined that this is the problem of UAT. But in the test, we have changed many mobile phones and force the surrounding 2.4G WiFi, of course, these are certainly not related to the strange shape of the test results. Originally, we are very interested in UAT test, can only have the opportunity to do anything, hoping that its performance is so strange.

Subjective listening

In the subjective listening test, we left the part of the SMSL home SP400 headphone amplifier to a few days later. Talk to the performance of the SMSL M400 decoder to match the speaker system. The test speaker section includes A100 and New Detk A600 power amplifier + Scanspeak D6620 Treasure + Vifa NE180W-08 6.5 inches combination as a reference. The contrast source selects the MR1 and torque sound of the MR1 and torque sound. Although both are functional and positioning, we are just a relatively high-end positioned CS4398 DAC and ESS 902x PRO DAC sound style.

Double Wood Sanlin S.M.S.L M400 USB External Decoder

Overall impression:

Regardless of the M400 I / V design, it makes us feel a lot, the M400 decoder is in the intermediate frequency, the high-frequency part of the dynamics of the high-frequency part is obviously different, and the sound line is bright. Even slightly excessive, and the three-dimensional outstanding highlights of vocals are even excessive. No more Ak449x on the kind of hearing because of insufficient dynamics and sound. However, it is instead of receiving some of the real neutral or even young and open-minded style in recent years. In the entire middle area, it is not so thick, this is not surprising, after all, AKM is also famous in the AK4397. And in low frequency, it is also a good performance.

Tao sound performance:

The SMSL M400’s treble performance is straightforward, Zhang Yang, no longer AK449X [at least 4497, 4495, 4490] so-called fine, sound becomes three-dimensional, dynamic is fierce, transient is quite sharp, in recent years, everyone has begun to pursue ” In the environment of warm sound, it is really rare to hear such a style. I really heard the AK4397 sound card, PCHIFI early feelings. This treble is not the ultimate details in the Chord Hugo series, in the extremely high frequency part, the M400 of the AK4499 does not deliberately modify it. Instead, in the high frequency, the high-frequency area sound is very dynamic, the transient speed is faster, and the sound is somewhat exaggerated, and even somewhat is brittle. There are some exaggerated “English” tastes, and traditional listening style, the natural coldness of Japan is different, it still has a very good line and dynamic.

Such trebles will be worried that they will be too hard, too hard? There is no problem with actual matching performance. It is only a style that is completely detached from the warm sound. Its high-stroke position is more brought. For the small truth, the high-strix copper instrument is exaggerated, the sound is obvious and more gorgeous, the line is also slightly unexpected. However, due to the high level of quality, there is no problem such as burrs, particles. When the treble with the pop-up type musical instrument, the speed is slightly faster, the exaggerated sound density may make some of the relatively weak recording noise, such as the front and rear noise of the synthesis, the stringed musical instrument in some recording Some so-called loosening, etc., it is very characteristic, but it may be slightly hard.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

Such a sound style is not very suitable for the recording itself, and it is not very suitable for more rigorous recording, it will feel that the treble details are good, but it is slightly exaggerated, highlighting, and the density is relatively abundant than the imagination. However, from the current viewing of the speaker system, as long as the quality of the high-profile speaker is guaranteed, the problem is not large. It may encounter problems with the earphones with earphones.

Such treble styles are also MR1 of the modified component or the 902x PRO series of ESS, in front of the AK4499 M400, can say that they are obvious and humid. However, from density and dynamics, M400 is stronger than MR1, which is close to ES9028PRO ELEMENT-M, and is more dense. But from a middle and high-end decoder, you can only say that M400 treble is very style, and it is still worse in aesthetic and level.

Middle sound performance:

Although we can affirm the M400 of the AK4499, most of the people have finally become three-dimensional, clean, solid, have a very good dynamic, but it is still not thick and warm. For the expression of young girls, such a style obviously strengthens the sound of the breath, and the salvation song is really strengthened. The so-called “mouth” sounds great. But the dynamics is good, and the sound stereo is always much stronger than that of all AK449x floating. Relatively speaking, such a style is also less suitable for the recordings of the smell song, which can’t blame the codec, and blame the taste of the fine. For mature women, the thickness is relatively short enough, but the sound tension, dynamics, lines, and the appearance are very good, and the style is really slightly young. The man’s performance is, even if it is a mature male voice, the sound of the sound and the losses are very good, the thickness is insufficient, and the light is light. Everyone should understand that the light brought by the thickness, and the sound of serious dynamic is not solid, it is very different. Basically, the AK4499 under the performance of the M400 should be changed to the problem before the AK449X is significantly insufficient.

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

In the performance of a large dynamic work such as symphony, its appearance position is relatively relatively, mainly the thickness of the medium-sound part is not enough, or relatively insufficient, and the medium and high frequency engagement portions are obvious. At present, this part of this part may be optimized in I / V and LPF portions, probably M400 is a bit exaggerated. Of course, for such performance, it is very suitable for symphony. After all, the typical EQ of symphony is also called. Its intermediate frequency, medium and high frequency dynamics are very good, strong, and the sound is biased in the medium and high frequency area, slightly more gorgeous. The control force of the intermediate frequency region is good. The sound relaxation is better, even better than MR1 dynamics and control.

Bass performance:

M400’s middle and low-tone part of the M400 seems to be the most obvious defect of the entire machine. The reasons are unknown. It is estimated that there is an optimized space, which is not a problem with the DAC chip itself. In the low frequency, there is a deep part, there is a good strength and the depth of dive. It should be noted that the details of this section may require a large-scale medium and low-sounding speakers to express, such as the A100 should not be well reflected in its advantages. Compared with ESS 9028PRO, low-frequency dive deeper part is quite, slightly weak, and the post-delay transient speed is slightly faster. The difference in thickness in the middle and low frequency is large, and it is also weak in MR1, which also leads to its overall listening feeling is not so thick. Of course, this may also be AKM that has always liked. In addition, it seems that the device of AKM should not be expected, expressing low frequencies like ESS or PCM179X, which may be almost zero. In a very large dynamic, in the low frequency of the big sound, the low frequency of the M400 is satisfactory, and the details are also good. It is better than what previously evaluated national tiles AK4497 / AK4493, and it is basically the same as its intermediate frequency, and the AK4499 will be considered to return to normal dynamic performance, and the voltage type AK449X has different. It is only necessary to work hard to optimize in the middle and low frequency section.

Summarize

The first time I heard the AK4499 decoder SMSL M400, which seems to have more than ten years ago, AK4397 sound card, PCHIFI’s early taste. The sound is straightforward, pursues the lines, dynamics and densities of treble, medium and high-stroke parts. The intermediate frequency does not pursue a very warm thickness, but it is tall, three-dimensional, clean, and better control. Unlike the so-called monochronic monitor style, AK4499 M400 is still good, no problem such as burr, unhirpiece feelings because it is too strong with high-stroke density and public style. Just in the performance of the recording products that have a heavy taste, it is not suitable. For normal recording, M400 will make a more vast vitality, slightly bright.

Today, although we first heard the sound of AK4499, it is also hoping that it can optimize in medium and low frequency, so that the thickness is slightly enhanced, and there is a convergence in medium and high frequency densities, don’t come too much.

Because we first heard the sound of AK4499, for trends, style analysis is just a beginning, and it is sure to talk about accuracy. But we have seen the design of AKM external I / V for more than ten years, I hope that we can hear changes in subjective sounds and I / V external design, and hope to be optimized by I / V, LPF. Good AK4499. More desirable is that AKM’s DAC chip, at least on music appreciation equipment, launching more external I / V version of the low-end models of AK449x. After all, for music appreciation, that is, the D / A core is in parallel, 110dB-140DB differences, really do not have I / V design, not to mention AK449X, the market may become a hundred equipment in the market. Show?

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」

双木三林 S.M.S.L M400 解码器测评报告 「SOOMAL」