The Well-Tempered Computer, an introduction to computer audio

Friday, December 6, 2013

Motherboard for audio

Gigabyte is the first company known to me selling a mobo with audio quality as a sales argument.
It features a dedicated USB port with clean power.
The onboard audio has socketed op-amps and adjustable gain.
They also claim to shield the analog components from noise at PCB level.

Gigabytes GA-H81.Amp-UP

Saturday, November 23, 2013

Hegel Super headphone amplifier

Digital inputs: USB micro
Outputs: mini-jack (analog) + optical mini-jack (digital)
USB interface: up to 24 bit / 96 kHz, plug & play
Noise floor: -140dB
Output impedance: Below 1 ohm
Dimensions: 1,6 cm x 4,1cm x 8,2cm / 0.6” x 1.6” x 3.2” (HxWxD)

Website: Hegel
Price: $399

Sunday, November 17, 2013

Audioengine D3

24 bit / 96 kHz DAC with asynchronous USB input and headphone out.

  • Full-scale output 2.0V RMS
  • Frequency response 10Hz - 25kHz (+/- 0.5dB)
  • SNR (DC to 20kHz) 110dB
  • THD+N (1kHz FS 96 kS/s) <0 .002="" li="">
  • Crosstalk -110dB
  • USB transfer mode Asynchronous (dual clock)
  • USB device class Type 1.1 or above
  • Input USB Audio Input bit depth up to 24 bits (upsampled)
  • Input data rate up to 192KS/s (96K native)
  • Output Analog audio mini jack
  • Output impedance 10 ohms
  • Suggested headphone impedance 12 ohms to 10Kohms
  • Headphone amplifier LME49726
  • D/A converter AKM4396
  • USB controller TI1020B
  • Power requirement USB 5V DC, 200mA
  • USB power filtering 2-stage redundant regulation
  • Product dimensions 19x12x6mm (including USB connector)
Website Audioengine
Price: $189.00

Thursday, November 7, 2013


Pre-amp with analog, USB, Toslink and SPDIF input.
Analog line- and headphone out
Digital out (Toslink)

32-bit Texas Instruments PCM1795 DAC
XMOS-based asynchronous USB input 24-bit/192kHz
1/8" analog input couple to a AKM AK5386 AD converter (24-bit/96kHz) coupled with the amp and the Toslink output allowing for digitizing analog input.
USB input coupled with Toslink output ( USB to SPDIF conversion)

Website: AMI MUSIK DDH-1
Price: US$549

Thursday, October 31, 2013


WiSA is an open industry standard to connect speakers wireless.
It allows for lossless 24-bit audio with sample rates of  32, 44.1, 48, and 96 kHz
It supports 2 channel up to 7.1 surround.
It operates in the 5Ghz U-NII band.

At the present (2013) B&O is the only brand known to me using this standard.
As Pioneer, Onkyo, TEAC, Klipsch en Sharp are members of WiSA too, one might expect them to bring out models in the near future.

Beolab 17 speaker with WiSA and Toslink input

B&O Transmitter1 with analog and Toslink input.

The WiSA™ Association

Wednesday, October 30, 2013

Cambridge DacMagic XS

Cambridge DacMagic XS £99.95

Connections Micro USB input, 3.5mm analogue output 
Digital to Analogue Converter ESS9023 24-bit DAC 
Sample Rates Supported
USB 1.0 mode: 16/24-bit, 44.1kHz, 48kHz, 88.2kHz, 96kHz 
USB 2.0 mode: 16/24-bit, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz
Output Voltage 2V RMS
Max. Power Consumption 150mW 
Min. Headphone Impendance 12 Ohms
Frequency Response +/-0.2dB 20Hz – 20kHz
THD (unweighted):<0 .004="" td="">
SNR 103 dBr (unweighted) 
Crosstalk 66dB
Output Impedance 0.5 Ohms
Volume Steps 53 steps (54 different volume levels) 
Dimensions (W x H x D): 30 x 10 x 53.5mm (1.2 x 0.4 x 2.1’’) 
Weight 100g (3.5oz) 



  • Max headphone output at 1%THD @ 1KHz: 34mW(12 ohm), 60mW(16 ohm), 82mW(32 ohm), 86mW(56 ohm), 36mW(300 ohm), 19mW(600 ohm)
  • Channel separation 60~64dB (1KHz) 33ohms -50dB/<=±3dB
  • Frequency characteristics 20Hz~20kHz (±0.5dB)
  • Total Harmonic Distortion 0.033% (33ohms) , <0 .02="" 0.0085="" li="" mw="" ohms="">
  • S/N Ratio 95.5dB/32ohms , 98.1dB/56ohms , 101.6dB/300ohms, 102.1dB/600ohms 

Saturday, October 19, 2013

LH Labs Geek

Small portable USB DAC/headphone amp

  • Two outputs on all types (2 x 3.5 mm jack): line and headphones, both are variable in digital domain (64bit precision)
  • Volume control: two buttons and software (Operation System main volume slider sends volume data to Geek which implements the volume change in its internal volume control)
  • Line-out output impedance: 47 Ohm (on all types)
  • Headphone output impedance: 0.47 Ohm (on all types)
  • Max output voltage (line-out and headphone): 2.65 Vrms (Geek), 3,4 Vrms (Super Geek), 4 Vrms (Super-Duper Geek)
  • Max output power (headphone, 16 Ohm): 450 mW (Geek), 720 mW (Super Geek), 1000 mW (Super-Duper Geek)
  • Native decoded  music format in PCM: 44.1, 48, 88.2, 96, 176,4, 192, 352.8, 384 kHz / 16, 24, 32 bits.
  • Native decoded digital format in DSD: 2.822, 3.072, 5.644, 6.144 mHz / 1 bit
  • "Class A" analogue output stage, THD+N better than 0.005 %, SNR is 103dB (none-weighted), 109dB (A-weighted)
  • Sample rate indicator LEDs, machined aluminum enclosure in three different colors, with 6" USB cable, driver for PC (plug and play on MAC and Linux)
Website: LH Labs
Price: US$ 299

Tuesday, October 8, 2013

AURALiC Gemini 2000 headphone amp

DAC with a 2 Watt class A headphone amp build into a Klutz design headphone stand.

Output: 6.3mm jack / 4-pin XLR.

3.5 mm analog

Integrated SDXC card reader
File format: PCM 24/384, DSD128

Website: AURALiC
Price: US$1995

Monday, September 30, 2013

Resonessence Labs Herus

In case of small portable USB DACs there is the flavor of the month DAC
There is the Audioquest DragonFly doing 24/96.
This was pretty soon surpassed by the Meridian Explorer doing 24/192
Now there is the Herus supporting PCM up to 24/352.8, DXD and DS64/128

Herus $ 350.00

Small PCM and DSD capable USB DAC
63.5mm (2.5in) long, by 31.7mm (1.25in) wide and 19mm (0.75in) high

Asynchronous USB Audio 2.0: PCM bit width 24 or 16
Supported Data Rates: 44.1, 48, 88.2, 96, 176.4, 192 and 352.8 Ks/S
Supported Formats: PCM, DXD and DSD64/128 Uses DoP protocol 1.1 over USB for DSD
Operating Systems MS Windows, MAC OS and Linux
Use the Resonessence Thesycon Driver for USB Audio 2.0 on Windows
Output Signal Level At Maximum Volume level: 2.4 VRMS
Output Impedance:   0.2 Ohms
SNR at least 100 dB, Typically 108dB
THD at least 85 dB, Typically 90dB

Saturday, September 21, 2013

Sony HAP-Z1ES HDD Audio Player

Playback of DSD and the full range of Hi-Res file formats, Analog FIR filters, 1TB hard drive for local music playback and storage, DSD re-mastering engine converts all signals to DSD signals, built-in Wi-Fi for app control and music transfer.

A player with 1 Tb of storage but according to the specs can accommodate only 20.000 titles!

Price: £1,999.00 Incl. Vat

Wednesday, September 18, 2013

Tuesday, September 10, 2013


A Linux distribution with MPD for the audio optimized for (as you might have guessed) the Raspberry Pi.

-Ready to play, download it, flash it, wire it and you’re ready to go!
-Supports almost all DACs
-Bit perfect playback (up to 32bit 192 khrtz)
-Samba support, for reading music stored on NAS
-Fat32 and NTFS support, connect your USB storage and you’re ready to go
-Audio output also from analog Jack
-Only few process are active, less is more in audio reproduction
-Web-radio, Spotify and supported
-Mp3, Wav, FLAC, AAC, ALAC support
-A nice webgui to configure and control RaspyFi
-You can control RaspyFi with lot of Apps for Mac,Win, Linux, Ios and Android
-Wi-Fi support out of the box
-Fits on 2gb SD
-Beets is included, to manage your library and get rid of bad metatags
-Optimized to reduce SD card wearing
-Wi-Fi ready out of the box

Website: RaspyFi

Friday, July 5, 2013

Gefen USB DAC and converter

24 bit / 192 kHz USB DAC with RCA and headphone out.
Can also be used as a USB to Toslink convertor.
Driver for Windows.

  • Audio Input Connector: (1) USB Mini-B
  • Audio Output Connectors:
    • (1) TOSLINK (optical)
    • (1) L/R analog audio (2 x RCA female)
    • (1) 1/4-inch stereo headphone jack
  • Power/Streaming indicator: (1) LED, blue
  • Sampling Frequency indicators: (6) LEDs, blue
  • Signal-to-Noise Ratio: 110 dBA
  • Frequency Response: 10Hz - 20kHz ± 0.1 dB
  • Total Harmonic Distortion (THD)+N: <0 .02="" li="">
  • Operating Temperature: +32 to 104 °F ( 0 to +40 °C )
  • Operating Humidity: 20 to 90% RH, no condensation
  • Storage Temperature: -4 to +140 °F ( -20 to +60 °C )
  • Storage Humidity: 0 to 95% RH, no condensation
  • Power Consumption: 2.5W (max.)
  • Dimensions (W x H x D): 3.4" x 1.3" x 3.4" (86mm x 34mm x 86mm)
  • Shipping Weight: 1 lbs (0.45) kg
Website Gefen
Price: $129.00

Wednesday, May 15, 2013

Avantgarde acoustic - Zero 1

3 way active speaker with 2 horns for mid and treble.
All the digital inputs.
Crossover and room adjustment implemented in DSP

DriversSubwoofer: 30 – 250 Hz
Midrange horn: 250 – 2.000 Hz
Tweeter horn: 2.000 – 20.000 Hz

Digital inputS/PDIF
Analogue inputOptional (AD converter)
Amp2 x 50 watts + 1 x 400 watts
CrossoverDSP: 6 channel, 66-bit FPGA
Filter steepnessUp to 100 dB/octave
Filter typeProgressive FIR filters
Phase shifts< 5 degrees
DAC3 x 24-bit Burr & Brown
Master/slave radio link2.4 GHz ISM/SRD
Amplitude linearization*Yes
Phase linearization*Yes
Room adjustment/equalization*100 EQs, each with 16,000 frequency points
Weight30 kg
BxHxD490 x 1040 x 318 mm

* with optional software

Website: Avantgarde acoustic
Price € 9000

Saturday, May 4, 2013

NS2 Air Monitors

Small powered speakers with a wireless connection using Airplay

Power output: 80W peak power
Frequency response: 60 Hz – 22 kHz
Woofers: 3″ Kevlar with dual magnets, shielded
Tweeters: 3/4″ silk dome, shielded
Digital Signal Processor: 32-bit
Total Harmonic Distortion: <0 .15="" br="">Signal-to-Noise Ratio: > Alalouge 85dB, Digital 90 dB
Amplifier type: Class D
Crosstalk: <50 br="" db="">Impedance: 20k Ohms
Dimensions: H: 160 x W: 110 D: 140 mm
Weight: 3.0 kg
Cabinets: MDF

Website NOCS
Price: $449.00

Wednesday, May 1, 2013

Sonore Rendu

Ethernet to S/PDIF converter.

This is a DLNA/UPnP 2.0 compliant renderer.
It doesn’t have an interface but as it is a DMR (Digital Media Renderer in DLNA speak), you can control the volume using a DMC (Digital Media Controller).
A DMC can be a PC running a DLNA server/controller software like JRiver or a smartphone with DLNA software.
The schema explains it nicely.

One of the disadvantages of DLNA is the lack of gapless playback.
The Rendu supports it but the controller must support it too.
At the present the Rendu support gapless in combination with Bubble UPNP as controller on Android or JRiver on a PC.

The Sonore Rendu.i2s has Ethernet input and SPDIF/I2S over HDMI out.
A model including a ESS Sabre ES9023 DAC is planned.
At the present only 120 VAC models are available!

  • supports gapless playback*
  • supports DSD/DoP pass thru**
  • powered by an on board, extremely low noise, low output impedance linear power supply
  • isolated from noise on the network
  • operates fully asynchronously, using on board fixed frequency low jitter clocks
  • features a transformer coupled true 75 ohm SPDIF BNC output
  • has an integrated, 32 bit, high precision volume control
  • supports up to 24 bit playback at the following sample rates: 44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz, 192KHz
  • plays AAC, AIFF, ALAC, FLAC, MP3, and WAV files from HTTP streams
  • controlled via apps on your mobile device
  • UPnPTM AV 2.0 / DLNA compliant
    * Gapless is currently supported via Android with Bubble UPNP as controller, J-River on PC as controller with local storage. Check back for updates.
    ** DSD/DoP pass thru requires the use of MinimServer

Website: Sonore
Price US$ 1369

Rotel RA-1570

Two years ago a DAC featuring an asynchronous USB input was news.
Today, a DAC without async USB is news and as far as I am concerned, a showstopper.

In the amplifier world, async USB input is still rare.
Rotel is one of the exceptions to this rule.
I wouldn’t be surprised if in a couple of years a USB input is as common as a RCA.

Asynchronous USB 24 bit / 192 kHz
Wolfson WM8740
2x 120 wattAB into 8 Ohm

Website: Rotel
Price: € 1599

Friday, April 19, 2013


Asynchronous USB DAC at a bargain price

  • One USB-I2S Module plugged into the Analog Board
  • Golledge high-quality XOs at 22.5792 and 24.576MHz
  • Asahi Kasei AKM4430 DAC
  • Low-noise 3.3V LDOs by Demain and Oneoclock, or ADP151
  • RCA (phono) stereo output
  • Headers for alternative power supply designs
  • Unpopulated connectors for RS232, LCD etc.
  • Bootloader buttons so you don't have to pop open the box to reprogram the MCU
  • You must provide an USB 2.0 mini-B cable. It is not included.
Open source drivers for UAC2 (24 bit / 192 kHz) and ASIO.

Website: QNKTC
Price: US$ 135

Wednesday, April 3, 2013

Loss-less downloads

Looking for loss-less downloads?
Try these search engines.

FLACme is a search engine for finding CD-Quality (16bit 44.1kHz) music downloads in lossless formats such as FLAC, WAV, AIFF and ALAC.

Find HD Music is a search engine for finding high-resolution music downloads on the web.
The search engine lists high definition (24bit) downloads that are available from the major HD music vendors such as HDtracks, iTrax, Linn Records, Naim Label, eClassical, The Classical Shop, Channel Classics and HIGHRESAUDIO as well as smaller sites such as Melba Recordings. 

Friday, March 22, 2013

Moos Mini Aero

Active speakers with a lot of technology build-in.

  • Loss-less wireless audio up to 24 bit/ 96 kHz
  • Scan-Speak drivers
  • Wolfson DACs
  • Hypex amps

A complete 'who is who' in a small form factor.

Revelator R2904
Revelator 15W-8530
Quad differential DACs
SNR > 125dB
Analog Devices Asynchronous Sample Rate Converters
AmpHypex UcD
DSPAnalog Devices SHARC floating point signal processor, with 32-bit processing word size and 64-bit accumulator
Input Wireless (WATT)
USB dongle for PC and Mac

Website: Moos
Price: $2499

Monday, March 4, 2013

Matrix Audio X-Sabre

Looking at the connectivity of this DAC and its price, it will probably become the DAC flavor of the month.
  • Asynchronous USB
  • DSD×64 (2.8224MHz) / DSD×128 (5.6448MHz)over USB
  • Sample rates supported USB: 16-32Bit @ 44.1kHz/48kHz/88.2kHz/96kHz/176.4kHz/192kHz/352.8kHz/384kHz
  • Sample rates supported Coax/AES-EBU: 16-24Bit @ 44.1kHz/48kHz/88.2kHz/96kHz/176.4kHz/192kHz
  • Low latency ASIO/KS drivers supported
  • Drivers available for: Windows XP/ Windows Vista/ Windows 7
  • 4 ESS 9018 Sabre Reference DAC per channel

Website: Matrix Audio
Price: US$ 1,099.95 

Wednesday, February 13, 2013


Tagging classical is most of all a lot of work.
The internet databases in general recognize the CD but the results are often  a mess.

Don't be surprised if you get
Sonate für Klavier und Violine F-dur Opus 24 [Frühling]
Sonata No. 5 "Frühlings - Sonate"
The Violin Sonata No. 5 in F major “Spring”, Opus 24

Often the composer is stored in the artist field and the performer hopefully in the album title.

What you need is tags for Composer and Composition and have them populated in a uniform way.

The MusiCHI tagger addresses these problems.
It has pick list for Composer and Composition.

You can also batch process your collection (MusiCHI Clean)

The text processor offers a lot of options to cleanup your tags.

I do recommend the MusiCHI Tagger.
It is a real time saver when tagging classical.

More about MusiCHI

Website MusiCHI

Monday, February 11, 2013

Meridian Explorer

Portable USB DAC with analog volume control on the headphone out, fixed line out combined with Toslink out.
Asynchronous 24/192 USB (XMOS) with driver for Windows.
Website: Meridian
Price: € 295 

Thursday, February 7, 2013

Woo Audio WA7 Fireflies

Class-A tube headphone amplifier with asynchronous 24/192 USB Audio Class 2 input.

  • C-Media 6631 USB chip
  • TI PCM5102A 32-bit DAC chip
  • Distortion: <0 .03="" li="">
  • S/N: 95dB
Website Woo Audio
 Price: $999

Opalum active wireless speakers.

Even wireless active speakers needs power to drive the build-in amps.
Opalum has a very specific solution.
The speakers are fed (24 V) by a dual wire connected to a hub.
The signal is transferred over the same wire.
You can connect the speakers parallel or daisy chain them.

The hub takes care of the connectivity.
Analog and SPDIF inputs
Wireless b/g with Airplay and DLNA.

Website: Opalum

Tuesday, February 5, 2013


You like DACs?
An impressive compilation can be found here: DACInfo

Friday, February 1, 2013

Genelect G-series

Genelec is well known in the pro-world.
In 2013 they launched the G series targeting the home.
I do think active speakers for home use is becoming a new trend.

Website Genelec

Monday, January 14, 2013

For your ears only

You can buy custom molded in-ear monitors.
You go to an audiologist.
He makes an impression of your ear.
Send it to the factory.
Wait until they ship your custom-fit IEM.
Oh yeah, you have to pay a substantial amount of money too.

Why not rolling your own!

Take a pair of Sonomax Eers headphones.
Put them in your ears while attached to the thingy below.

Pull the trigger and don’t move your jaw for 5 minutes and you have your custom mold.
Source: eerscustom fit earphones

Sunday, January 6, 2013

Active crossover

Almost all speakers at the home are passive.
You have an amp, a box and inside the box there is a passive crossover.
It split the signal in a part for the woofer and a part for the tweeter.

Studio monitors are in general active.
Each driver has its own amp and the crossover is done on the signal before it enters the power amp.

Onkyo has released a couple of AV receivers enabling you to implement active crossovers using DSP.

A clear explanation of how it works.

A bit more: active crossover

Thursday, January 3, 2013

Parrot Zik

You won’t find headphones in this blog as there is nothing digital about two drivers and a wire.
The Parrot Zik is a “digital” headphone.
Not only is it Bluetooth enabled but it comes with DSP (Digital Signal Processing) allowing you to tailor the sound.

The Parrot Zik is designed by Philippe Starck.

Design is often about minimalism. Those elementary shapes like a cylinder, a cube, etc.
Starck is one of the few who can create beauty using organic shapes.
The Zik is no exception to this rule; it looks swell, is light, and wears nicely.
However, if you argue that one does not buy a headphone for the looks only, you do have a point.

The Zik is a Bluetooth headphone.
I do think Bluetooth is not exactly an audiophile Walhalla but fortunately you can connect it with a wire too.
This gives you a couple of options.

1-Wired only

I plugged the Zik into my Benchmark DAC 1.
Sound is really horrible, the plastic ear buds that comes with your mobile probably sounds the same. To make sure nothing was interfering I even removed the batteries but the same hollow sound remained.
Very weird, the simplest possible connection, just a wire sounds worst.


Put on the power and after a delay of a couple of seconds all of a sudden you have a decent sound. It’s a bit mellow and compered with my Etimotics ER4P lacking a bit of detail but it is decent. At least it is not bass heavy as so many modern headphones are.

3-Wired + Power + Smartphone

You can download the Parrot Audio Suite from Google Play.
This allows you to change the settings of the Zik.

ANC (Active Noise Cancellation)

I toggled between on/off.
The first thing I noticed was a dropout of about a couple of seconds, then the DSP sets in.
This happens all the time you change the settings using this App.
Bit surprised that it takes that long.
ANC slightly changes the sound but not as worse as in case of my Sennheiser PXC 360 BT.

Parrot Concert Hall

You can change the angle between the speakers and the reverb of the room.
Reducing the angle between the speakers is a nice feature as stereo over a headphone sounds like STEREO. It works more or less like a crossfeed.


I simply set it to flat.
Unlike many modern headphones, the Zik isn’t bass heavy.


Tried a couple of devices


No problems to pair the Zik with my Galaxy 2.
It uses A2DP with SBC for audio.
No APT-X here. I do think this a bit of a pity as APT-X sounds better than SBC but I wonder if this headphone is revealing enough to hear the difference.
Using the Parrot Audio Suite, you can invoke all kind of DSP as mentioned above.
This time there isn’t the delay as in case of a wired connection


I have a Bluetooth dongle to listen wireless to the TV.
The Zik cannot be put into pairing mode so no way to connect the Zik to the Bluetooth transmitter.
I asked Parrot support and they confirmed this is simply not possible.
You need a master device with and interface like a mobile to pair the Zik.


Win7 sure has an interface.
The Bluetooth of my HP sees the Zik and pairs flawlessly.
The moment you try to play some music, Win complains.
It is missing a driver. No sound at all.

Win Update cannot find the driver.
Could not find one at the Parrot website either.
According to the Parrot forum
unfortunalty your Asus is using Atheros Bluetooth stack which is currently not compatible with Parrot Zik. That is why when you connect your Zik in Bluetooth to your Asus, it fails on the last step.There are no solutions at the moment and we strongly recommand to use your Zik with Line-in on this specific computer.
After trying all kind of things, I simply opened the properties of the Zik.

The Bluetooth Peripheral Device driver is missing.
Went to the Service tab.

Disabled the Parrot RFcomm service.
This turned out to be the trick to get it to work in Win7.
Obvious Parrot needs to improve on the Win side.

The Zik now pops up in the Win audio panel.
As mentioned before the Zik can be configured with the App.
There is no Win version available.
If you want to change the settings when connected to the PC,you have to:
  1. Disconnect the Zik in Win
  2. Connect it with the smartphone
  3. Use the Parrot Audio Suite to change the DSP settings
  4. Disconnect from the phone
  5. Connect to Win
A tedious procedure but unavoidable as the Zik can’t communicate with 2 devices at the same time.


What happens if an ace designer and a Bluetooth car kit manufacturer joins forces?
You spend € 350 and get a beautifully styled headphone with too many glitches.


Zik: 1.03
Android App: 1.0

Lector D i g i t u be D S D

 DAC with a tubed output stage (ECC-81/12AT7)

Asynchronous USB support up to 32 bit / 384 kHz. Driver for Windows
Supports DSD over USB


- Spdif IEC-958 as RCA connector / 192 Khz 24 bit
- Spdif IEC-958 as BNC connector / 192 Khz 24 bit
- AES-EBU AES-3 as XLR connector / 192 Khz 24 bit
- Opto toslink digital input / 192 Khz 24 bit
- Asyncronous USB / 384 Khz 32 bit
- Word Clock

Unbalanced output / 2.5 volt 250 ohm

Website: Lector
Price:  € 1990