Audirect Whistle review

The Audirect Whistle is small in size but Big in Sound…




1. About Audirect:

Audirect is part of Shenzen Micronetwork Technology Co., Ltd. located in Shenzen – China and is engaged since more than 5 years in the development, production and sales of portable DAC’s. The Whistle is the second generation there audio line.


2. Disclaimer:

First of all, a big thanks to Audirect for providing me a free sample of the Audirect Whistle for review purposes. I am not affiliated with Audirect beyond this review and these words reflect my true, unaltered opinions about the product.


Official website of the Company

3. Price:

The Audirect Whistle DAC/AMP is sold for 99,00 USD

Purchase Link:     



4. Introduction:

The Audirect Whistle is a small Hi-Fi DAC and Headphone Amplifier created for people who are not satisfied with there onboard PC soundcard or the sound and output power of there Smartphone’s or Tablets.

5. Package and Accessories:

The device comes in small white card-box and contains the following items;

  • 1 pcs of Whistle PCM/DSD DAC/AMP
  • 1 pcs of Micro USB cable
  • 1 pcs of USB Type-C cable
  • 1 pcs of Lightning cable
  • 1 pcs of long profile 3.5mm to 3.5mm cable

Audirect has put some nice accessories in to the package. Those are 3 digital OTG and 1 analog connection cables. The Lightning and USB Type-C OTG cable is a free bonus. When you plan to buy it separately you must spend normally 13.90 USD for the Lightning and 9.90 USD for the USB Type-C cable.



6. Design and Build Quality:

The Audirect Whistle is a very compact and small (better say tiny) device that has almost the same size of an AA type battery. It is very lightweight and is only weights only 12g.


It has a triangle shaped design with rounded corners and has an all metal housing. The all metal housing is made of aluminum material and is very well made.

The device has a smooth surface and is painted in one color; only the top and bottom corners are not painted and are appearing in silver metal color. The device is available in 2 different color options and those are gray and red. My review sample came is in red color.


On the top of the device is the 3.5mm headphone/analog out that is compatible with 4 and 3 poled jacks.


At the bottom is Micro USB digital out that allows you to connect it to devices with USB 2.0, Micro USB, USB Type-C and Lightning connection like Tablets, Smartphone’s, PC and MAC that supports external USB DAC’s.


On one of the front surfaces are the Audirect Logo and two LED lights. The PCM marked LED lights up when a PCM conversation is in process and the DSD marked LED lights up when you play a DSD (Direct Stream Digital) file.



7. Technical Specifications:

  • DAC : ES9018Q2C
  • AMP                           : ES9016
  • Frequency response  : 20 – 30000Hz ( -0.15dB)
  • Distortion                    : 0.0004 %
  • SNR                           : – 128dB
  • DNR                           : +121dB
    Output Power Rating : – 115dB THD+N, 2Vrms into 600Ω
  • Output Power Rating : – 100dB THD+N, 49mW into 32Ω
  • Output                        : 3.5mm (supports 3 and 4 pole headphone jacks)
  • Input                           : Micro USB (from Micro USB, USB Type-C and Lightning)
  • Resolution                  :  PCM 16 up to 32bit/384kHz sampling and Native DSD 1bit/2.8MHz/5.6MHz DSD
  • Demission’s                : Length: 51.0mm Wide: 14mm Height: 14mm
  • Weight                        : 12g


8. Hardware and Software:

The Audirect Whistle is a small DAC but has some nice hardware specs. The Whistle has no battery and any physical volume control button/wheel.

 a) DAC Section:

Inside the Audirect Whistle is the ES9018Q2C DAC of the company ESS Technology Inc.

The ES9018Q2C is a 32-bit Stereo D/A Converter with Integrated Headphone Amplifier and Output Switch. The SABRE9018Q2C SOC (in short System-On-a Chip) is capable to deliver an SNR (Signal to Noise Ratio) of 121dB, THD+N (Total Harmonic Distortion) of -115dB.

The ES9018Q2C SOC operates from a single +3.3V supply.

The ES9018Q2C features ESS’s 32-Bit HyperStream® architecture that handles up to 32-Bit 384kHz PCM data via SLIMBus, I2S, or DSD-11.2MHz data.



b) AMP Section and Drivability:

The Audirect Whistle has an ES9016 amplifier of the company ESS Technology Inc.

The ES9016 is an on board amplifier that is integrated in to SOC of the ES9018Q2C. The output rated of 49mW into 32Ω and 2Vrms into 600Ω. It was capable to driver my Audeze iSine20 and Audio-Technica ATH M50 to very loud sound volume levels.

c) Battery Draining:

The Whistle has less battery drain than the first generation of Audioquest Dragonfly and other devices like the Fiio E10K.

d) Hissing:

I was very surprised to hear such a clean sound output form such a priced device. I don’t know the performance of the first batch, but the Whistle is a great performer if you have a sensitive to hissing.

The Audirect Whistle sounds very clean with some of my sensitive IEM’s like the HiFi BOY OS V3 and the DUNU Falcon-C, even in very high volume levels. I think that the Audirect team did a good job by making such silent device for this price.

e) Compatibility:

The Audirect Whistle works flawless with Windows PC, MAC, iOS and Android devices.

The Whistle installs the required drivers at the first connection and everything runs automatically. A MAC device doesn’t need any driver installation.

Windows10 Whistle

My Ipad Air 2 did automatically recognize the Whistle as a plug and play device.


My Samsung Galaxy S8+ Android Smartphone is working flawlessly and doesn’t need any additional third party software.


9. Equipments used for this review:

DAC’s                         : Audirect Whistle, Audioquest Dragonfly Black

Digital Source           : Ipad Air 2, Samsung Galaxy S8+ and Dell 5521 Laptop
IEM’s                          : Audeze iSine20, Dunu Flacon-C, HiFi BOY OS V3, TFZ TEQUILA1,
Earbuds                     : NiceHCK EBX, HiFi BOY Dream

Headphones              : Audio-Technica ATH50M


10. Albums & tracks used for this review:

  • Sebastian Ingrosso, Thommy Trash &John M. – Reload (Apple Music)
  • Michael Jackson – Billie Jean (DSF)
  • Casey Abrams – Robot Lovers (Tidal Hi-Fi)
  • Emmanuel Pahud (Claude Debussy) – Syrinx (Flac 16bit/44kHz)
  • Melody Gardot – Who Will Comfort Me (Flac 16bit/44kHz)
  • Aretha Franklin – I Say a Little Prayer (DSF)
  • Diana Krall – So Wonderful (DSF)
  • Otto Liebert & Luna Negra – Up Close “Album” (DSF) – Binaural Recording
  • Alboran Trio’s – Cinque Lunghissimi Minuti (Flac 16bit/44kHz)
  • Megadeth – Sweating Bullets (Flac 16bit/44kHz)
  • Opeth – Damnation (Tidal Hi-Fi)
  • Metallica – The Black Album (Flac 24bit/96Hz)
  • Lorde – Royals (Flac 24bit/48kHz)


11. Supported Audio Formats:

The Audirect Whistle supports the following formats that I have tested out during this review;

Native DSD (64/128), FLAC, ALAC, APE, WAV, AAC, OGG, MP3, WMA

12. The Sound:

 I have burn-in the device for approx. 100 hours before I wrote this review.

Please note that this is a low budget DAC and all my comments about the sound quality are in consideration of this price range.

Tonality / Bass / Mid / Treble / Soundstage & Imagine:

The Audirect Whistle is a quite balanced sounding source with a hint of warmth that avoids making it sound too dry.

I have use the Audirect Whistle with my Samsung Galaxy S8+ (Smartphone), Ipad Air 2 (Tablet) and Dell 5521 (Laptop).

The improvements on any source I have plugged the Whistle was clearly noticeable. The first noticeable thing was a better authority in the bass department. The improvement of the sub-bass extension on my The Galaxy S8+ was immediately noticeable. It was able to provide a better sense of sub-bass power in the 20-50 Hz range.

The Whistle has also the better mid-bass presentation and control. The quantity and quality is good enough to avoid any lose of definition. My Dell 5521 (Laptop) and the Galaxy S8+ have some problems to handle the speed of the mid-bass range, especially in bass heavy songs that need additional speed and control. The mid-bass improvement was best noticeable on my Dell 5521 that has an onboard soundcard. The Ipad Air 2 the best bass department right after the Whistle.

The midrange of the Whistle sounds slightly more forward than the above mentioned sources. The midrange clarity is quite good and benefits form the clean background of the device. The biggest improvement was the detail retrieval on all plugged devices. The midrange improvement on my Dell 5521 was dramatically especially in the upper midrange; while the change in quality was less noticeable with the Galaxy S8+ and the lowest on the Ipad Air 2.

The Audirect Whistle has some pretty good clarity in the treble area. It has the smoother upper treble register and it sounds also more transparent than all the three sources that I have mentioned above. The improvement is best noticeable on the Dell 5521 and less on the Ipad Air2.

The increasing of soundstage is noticeable but not in a marginal way. There is some improvement for the depth on my Galaxy S8+ especially on the Dell 5521. The wide of the soundstage on the Ipad Air 2 is already for a tablet, but gets quite step further with the Audirect Whistle.

13. Comparison:

Audirect Whistle vs. Audioquest Dragonfly Black (v1.5):

The Audioquest Dragonfly Black is USB Stick-Sized Digital-to-Analog Converter (DAC) that is also compatible with Apple and Windows PCs, as well as iOS and most Android mobile devices (requires Apple Camera Adapter or OTG adaptor for Android).

Accessories, Design and Build Quality:

The Dragonfly Black is a small device but is bigger in size compared next to the Whistle. The outer shell of the Dragonfly Black is made of plastic that has a rubber like coating that gives a nice touch feeling, while the Whistle has an all metal shell with a smoother surface. One thing that I don’t like about the Dragonfly series is the use of a plastic cap that maybe protects the USB male connector of the device but can be easily lost.

The package of the Dragonfly Black includes only the leather case, no low profile cables for mobile devices that Audirect Whistle has already in the package.


Hardware Comparison and Compatibility:

The Dragonfly Black has the 32-bit ESS 9010 DAC with minimum-phase filter under the hood. The Audirect Whistle on the other hand uses the newer DAC chip of the ESS family the ESS9018Q2C.

The Dragonfly Black has the advantage that there is no need for any cable if you use the device with a PC or MAC but makes is more bulky that the Whistle. The Dragonfly Black has also this nice colorful LED indicator with the look of a Dragonfly that shows which bit-rat is actually active. The Whistle has also two LED indicators one for PCM that is active for all bitrates (except of DSD) and one for DSD.

The Dragonfly Black supports sampling rates up to 24-bit/96 kHz but doesn’t support DSD files. The Whistle in the other hand supports sampling rates up to 32bit/384kHz and has Native DSD capabilities for sampling rates up to DSD64 -1bit/2.8MHz / DSD128 – 1bit/5.6MHz.

The Dragonfly Black doesn’t need any drivers for PC and MAC devices but needs and CCK (Camera Connection Kit) for IOS devices (that you must buy separately) but without the need to install any software, but doesn’t works great with Android devices. To pair the Dragonfly Black with Android device, you need an USB OTG (On the Go) cable (must be bought separately) and you should install third party applications like USB Audio Pro that costs additional money to active the hardware volume control. The Whistle automatically installs the drivers to your PC and doesn’t need any software for MAC, IOS and Android devices. The cables to connect to these devices are also included to the package that is a big plus.

Both devices have nearly the same battery drain effect to the device they are connected.

The Dragonfly Black has an output voltage of 1.2 Volts and has more output power than the Whistle that performs very well with IEMs.



The Dragonfly Black’s sound signature reminds to this of the Chord Mojo, especially the warmth and musical sound presentation. The Whistle has the more balanced sound tuning compared to the Dragonfly Black.

The bass on the DF Black has more punch and gives a nice hint of warmth. The Whistle on the other side has less bass impact but with better speed layering and control. The bass definition is nearly equal.

The mids on both devices is sounding quite detailed and but after an intensive listening period with both devices, I have come to the decision that the Audirect Whistle has the better detail level for instrument and vocal presentation. The Whistles layering of mids is also superior compared to the DF Black.

The treble range of both devices sounds quite controlled and with nice detail retrieval, that has a performance above this price point. The Whistle has more treble focus and sounds more lifelike, but the DF Black has the advantage with its better control in the upper treble register.

The soundstage of both devices is above average not ultra wide or claustrophobic. Both devices have a nice sense of depth and above average performance for soundstage wideness.


No doubt, the Audirect Whistle sounds much cleaner that the DF Black. The DF Black has a small amount of hissing with sensitive IEM’s, while the Whistle is the cleanest sounding DAC I have tested in this price range to date.


14. Conclusion: 

The Audirect Whistle is a small DAC with a good build and sound quality that has lots of accessories (low profile cables) and almost no hissing that is a big welcome, especially in this price range.

15. Pos and Cons:

  1. + Tiny form factor
  2. + Lots of low profile cables/accessories
  3. + Plug and Play capability for Android and IOS
  4. + Pretty good sound presentation
  5. + Low to none hissing


  1. – No independent volume control
  2. – No battery means additional battery drain for the source

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