Sunday, August 30, 2015

cMP2 = cMP + cPlay The start of high end PC audio?

Achieving audio nirvana using a PC transport has long been the audiophile dream. One of the earliest software initiatives to achieve high quality rendering on a PC transport was cMP2 = cMP + cPlay. 

cMP2 had what I would consider a cult following which started around 2008. cMP2 provided fairly novice PC audio buffs with a rendering package that really stood head and shoulders above everything else available at that time. Nothing could really rival the sound quality cMP2 was providing with its combined software and hardware computer transport solution. 

Now for those PC audiophiles that have been wrapped up in the world of Foobar2000 or Jplay, its possible you may have never heard of/or tried cMP2. 

So a quick overview is in order. 

The cMP2 cPlay website describes how to build and configure a PC music player & PC transport costing around $1,000 (In 2008 dollars) that exceeds the performance of the very best CD transports at that time. 

A promise of a PC spdif output with less than 50pico seconds of jitter.... was considered vastly better than its competitors or mainstream digital sources such as the Logitech squeezebox which was around at the same time.  The only draw back was the PC configuration, optimisations & modifications both hardware and software which were required to assist cMP2 to perform at its audiophile best. cMP2 optimisation guide

The cMP2 website is fantastic and very comprehensive. The website provides all the FAQ's and how to guides you will need. There's definitely no point covering the same detail here when its already so eloquently presented on the cMP2 website. Just beware cMP2 is for computer audiophiles with a decent grasp of computing and Windows XP/7 OS knowledge. 

CMP2 cplay cmp - grizzlyaudio






Software Specs

Lets have a look at the software specs (Taken from cMP2 website). 

Playback, Stereo only
WAV  (16, 24, 32 PCM; 32 float)
FLAC (16, 24, 32 PCM)

DSP Design
28 bit processing (SIMD & streaming used)
Multi-threaded (event driven architecture)
Multi-core (semaphores at hardware level)
Upsampler/Resampler

Bandlimited Interpolation via "libsamplerate-0.1.5 (SRC)" [*1]  or     (145db/121db SNR selectable) (154db/120db rejection)

Multi-Stage Interpolation via "SoX-14.2.0" (VHQ/HQ selectable)       (175db/125db rejection) (clipping, if needed, done after attenuation)

Attenuation  [-100.0,0.0] in 0.5db steps (53 bit resolution)

Balance Control [-6.0,+6.0] in 0.1db steps Left(-ve), Right(+ve) (53 bit resolution)

Polarity Phase 0/180 selectable "in flight"
VST Support VST 2.4.2, Single low-latency plugin design, (2-in/max 8-out, 32 float, clipped)

Audio Output, 32 bit ASIO 2.2 (and backward compatible) 
Please note KS, DS, WASAPI are not supported

Operating System XP, Vista or Windows 7

Minimum Processor, "Pentium 4" type (SSE2) (core iX 32nm recommended)
Instruction Set, SSE2 (SSE4 recommended)

Minimum available RAM required, 160MB

Maximum available RAM used, 1GB

Maximum tracks in cue sheet, 160 (including track splits)

Operation 

Essentially cMP2 operates as a bootable and highly configured windows shell, which was highly optimised over 3 years for high quality audio playback and low resource usage. cMP2 optimises essential windows XP & 7 architecture, ready for cPlay (the player) to play your music files.

CMP2 cplay cmp - grizzlyaudio
Picture from: cicsmemoryplayer.com
A free downloadable copy of cMP2 & cPlay can be found here:
http://www.cicsmemoryplayer.com/ 

cMP2 download 


CMP2 cplay cmp - grizzlyaudio


cPlay download 


CMP2 cplay cmp - grizzlyaudio

Remember to download both cPlay and cMP...... you will need to download the correct cPlay instruction set for your CPU type, so pay attention here. 

As per the photo above suggests there are 4 possible instruction sets. 



cPlay setup 

Once installed, you should be presented with an interface similar to this. Simply choose your Driver and output device. You can also select your preferred output rate and re-sampler value. 

Once again I would suggest you mosey on across to the cMP2 website which provides a very detailed setup and interface guide. 


CMP2 cplay cmp - grizzlyaudio
cPlay playback screen

Once setup is complete. Simply select and load the songs you wish to listen to by clicking on the folder icon. 

The cPlay screen allows you to control. 
-Volume 
-Track / Song selection
-Stop, play, pause, FF, RW 
-Phase 
-Left right speaker balance 

You will note cPlay provides no support for album art. 


cplay - grizzlyaudio


Retrospective Review 
  • MQN has redefined what is both possible and expected from a highend minimalist PC software player, MQN is the clear leader in PC audio playback. 
  • cMP2 cPlay clearly provides a low jitter PC rendering solution. However software packages such as JLPDaphile present a more convenient modern approach, with minimalist headless operation and large library management. 
  • Playpcmwin is comparable in quality to cMP2 without all the installation fuss
  • cMP2 imaging is more centered than Vortexbox, however Vortexbox presents a wider and 'more' 3D image 
  • cMP2 cPlay feels more analog than Vortexbox, Vortexbox is more dynamic  
  • cMP2 has great bass tone although slightly less in weight when compared to MPD Linux setups 
  • cMP2 has very detailed setup/installation instructions, more modern packages are more easily installed 
  • cMP2 requires registry tweaks for best possible performance - not for everyone 
  • Pretty old skool operation, no album art or headless operation 
  • cMP2 is free to try, but so is Vortexbox, Daphile, Volumio, MusicBee, JLP, MQN, etc etc  
  • cMP2 is not a management solution for large music libraries. Consider using modern solutions if this is a key requirement
  • Cue sheets are mandatory for album or playlist creation 
  • cMP only provides ASIO compatibility for windows mixer bypass. NO DS, KS, or WASAPI support is provisioned



Friday, August 28, 2015

Vortexbox Music Player, NAS & CD Ripper

Today's audiophile literally has the pick of software to achieve audio Nirvana. A plethora of options exist both free and paid. 

On one side of the coin over achieving minimalist players such as MQN deliver unmatched superior sound quality via a minimalist approach and software footprint. On the other, we have the all singing all dancing software packages such as daphile, volumio, JLP, MusicBee, Foobar2000, Logitech squeeze server..... which provide advancements in GUI aesthetics and function yet fail to deliver the same rendering performance possible via MQN. 


It would be difficult to argue that the Holy Grail for any computer audiophile is a rendering package which delivers amazing audio playback with the convenience of headless operation. For a long time it has held true that if a computer audiophile wanted faultless music rendering performance, one needed to forgo headless control conveniences to do so.

Sadly this seems to still hold true, ultimate sound quality costs and its seems convenience is the currency. Less is definitely more and rendering software like MQN takes no prisoners in its ability to demonstrate the highest PC rendering performance possible. 

Yet as I get a little older and hopefully wiser, my willingness to compromise ultimate sound quality for a little convenience becomes more appealing. I find myself looking for middle ground. 

Let me introduce Vortexbox. A free open source bit perfect headless music player and CD ripper. VortexBox rips CD's to FLAC while allowing mirror copies of the files in lossy MP3 formats; MP3 320, MP3 V0, MP3 V2, MP3 plus Apple's loss-less codec ALAC (M4A). 

Vortexbox can be installed on just about any old PC you may have lying around, turning it into a music streaming, NAS serving, CD ripping bit perfect music solution. Paired with your USB DAC or PCI spdif/soundcard of choice and you have yourself a "super affordable" audiophile PC transport. 

Some key features of Vortexbox include: 
-Gapless playback and control via app based programs 
-Quick and reactive control/song selection and playback
-Web Interface for configuration / Headless Operation
-Control apps render album art, artist and track information 
-Works with external USB sound devices (DACS) & internal PCI sound cards 
-Automatic tagging of music files 
-Automatic cover art downloads 
-Automatic sharing of file to SMB file shares.
-Automatic re-indexing Squeezebox Server after every CD is ripped.
- Automatic sharing of all MP3s for streaming to iTunes and Roku Soundbridge.
-DLNA support 
-PLEX Mediaserver support
-Good support for Sonos.

Personal Sound impressions  
-VB presents an extremely dynamic, open and wide image/soundstage 
-Imaging is super accurate. 
-Great bass weight
-Great insight, with a slight tonal high frequency/Midrange emphasis when compared to Foobar2000 or cMP2 cPlay. Foobar for interest - images flatter than either Vortexbox or cPlay, less holographic.  
-Very detailed midrange and high frequency presentation
-Excellent compromise between sound quality and convenience/headless operation 
-VB does however have a slight midrange grain which is not as smooth as players such as CMP2 or MQN player. This is pretty typical of Linux/Alsa based transports/software. 

Installation 
Installation of Vortexbox is quite simple. A free downloadable copy of Vortexbox can be found here: Vortexbox Downloads.

Your beginners how to guide is here: 

Beginners guide to Vortexbox 

Simply copy and mount the ISO and run the CD as a bootable disc, installation takes about 10 minutes. A comprehensive how to guide, is found on the website

Vortexbox Documentation

Once installed, simply scan your network for the devices IP, go to your PC browser and type the IP address to access your headless configuration interface.


Vortexbox Web interface 

Click here for a very good overview of the web interface options.... 

During software installation VortexBox is dynamically assigned a local IP address. Once your VortexBox boots the units IP address will be displayed in the terminal above the login prompt (visible if you have a local monitor connected).

Alternatively grab your phone, PC, or tablet and scan your network to locate Vortexbox IP address. I would recommend Fing for this purpose. Once located it is advised to set a static IP address for your unit. Once completed 
you will be able to access the web GUI to begin configuration of your device. 

The web homepage is accessible at http://vortexbox. Or simply type in the IP address of your Vortexbox box in your browser URL bar. 
Vortexbox GUI web login Grizzlyaudio
Picture from: Google images


The web interface allows users to configure their Vortebox, time zone, music libraries, audio output device, sampling either plughw or hw direct, tagging settings, etc. 


The web interface is simply and very intuitive to make your way through. Once you have configured your Vortexbox, download an appropriate control app like MPod/MPad, Peng, or squeeze controller from your local android or apple store... so you can start listening. 

Headless control 
Vortexbox apps GrizzlyaudioLets face it, these days computer audiophiles expect headless operation. Look no further than the following control apps to provide a seamless and convenient palm of your hand control experience.  

MPod = Apple iphone/iPod controller + Free 

MPad = apple iPad controller + $2.50 from the app store 

MPoD and MPaD are really great apps for controlling your Vortexbox installation. You can use the them to directly control VortexBox Player. 

I have found MPod to be a fantastic control app. I personally find it a much more refined and stable control app when compared to squeeze controller. 

MPoD is fast, responsive & offers Gapless and noise FREE song changes!!. (No sync loss on track changes). In comparison I have found squeeze controller produced some DAC sync loss. Short burst of white noise between song changes and selections. 

To provide some additional information here is a short tutorial on how to configure your album art, very helpful. 
VortexBox & MPoD

MPod is dead silent and very quick.  
MPod is my Vortexbox controller of choice. A first class app. 

Key app features: 
Vortexbox apps Grizzlyaudio
-Gapless playback 
-Connects to your MPD server over TCP/IP.
-Automatically find MPD servers that make themselves know via Bonjour/Zeroconf.
-Supports the use of a password for making a connection to the server.
-Store multiple connection profiles.
-Fast application startup.
-Now playing screen shows active playlist and playing song.
-Cover art from Amazon or local http server.
-Volume control.
-Move to previous, next song.
-Move to any song in active playlist.
-Seek in song.
-Toggle random, repeat.
-Stream mp3 directly to iPhone via icecast 
server or mpd (v0.15 or above).
-Play random album or random songs by shaking your iPhone.
-List of artists with drilldown to albums and songs.
-Option to hide artists that only appear on compilation albums.
-List of albums with drilldown to songs.
-Option to group songs into albums based on server directory.
-List of songs, which also displays artist and album for each song.
-All lists are searchable.
-List of all playlists.
-Save the active playlist into a saved playlist.
-Choice between ‘add to active playlist’ or ‘replace active playlist’.
-Support for last.fm.
-Full iOS4 compatibility including background operation, remote control functions, retina display.
-Works well with Mopidy (mpd like Spotify player).
Peng iPAD 

Apple iPad controller + $10 from apple store 

If your willing to pay maybe consider this great iPad app. 


Vortexbox apps Grizzlyaudio
Picture from: Google images

Squeeze controller - Android or IOS 


Vortexbox apps GrizzlyaudioLogitech Squeezebox™ Controller provides a "free & open source" fully featured remote for your Vortexbox server. Installed on either your android phone or tablet Squeeze controller utilises your home Wi-Fi to control your Vortexbox player. Squeeze controller is available for both android and IOS devices.... 


Key app features: 
-Gapless playback 
-Connects to your MPD server over TCP/IP.
-Playlist management 
-Automatically finds MPD servers that make themselves known
-Fast application startup.
-Search function 
-Streams internet radio 
-Now playing screen shows active playlist and playing song.
-Random song selection 
-Song or playlist repeat 
-Cover art from local files 
-Volume control.
-Move to previous, next song.
-Move to any song in active playlist.
-Seek in song.
-Toggle random, repeat.

Vortexbox apps Grizzlyaudio


MPDroid - Android -$Free 
Vortexbox apps GrizzlyaudioSolely an android app MPDroid allows you to control any MPD/Vortexbox server and stream music from it. Google play link. 


The app comes highly rated on the google play store.

The GUI is intuitive to setup and use. Best of all MPDroid is free, so there's no excuses for not giving it a go. 

Key app features:  -Gapless playback 
-Connects to your MPD server over TCP/IP.
-Automatically finds MPD servers that make themselves known
-Genre music selection 
-Fast application startup.
-Search function 
-Streams internet radio 
-Now playing screen shows active playlist and playing song.
-Random song selection 
-Song or playlist repeat 
-Cover art from local files 
-Volume control.
-Move to previous, next song.
-Move to any song in active playlist.
-Seek in song.
-Toggle random, repeat.





Sunday, August 23, 2015

MusicBee Review 2015

With so many software player solutions available, its really difficult to know which player is right for your music player needs. 

Enter MusicBee a powerful free Windows based music player and management platform. MusicBee aims to make music playback and file management super easy. Bringing together a smart mix of form and function MusicBee has produced an intuitive and powerful music platform. 


MusicBee doesn't pull any punches, the software is squarely aimed as an alternative to Mediamonkey, Foobar2000 and maybe even jriver..... does it deliver - lets find out. 


Lets firstly take a quick look at some of MusicBee's key features. 

MusicBee - Grizzlyaudio- File conversion  
- Gap less playback 
- Intuitive interface 
- Rigging and file organisation 
- Equalisation & DSP options 
- Mono Down mix 
- 44.1khz to 192khz playback (16-24bit depth)
- Re-sampling & Up-sampling 
- Bit perfect output 
- Asio & Wasapi output
- Tagging & music management capabilities
- Stereo enhancer for headphones
- Balance control for stereo and headphone users

MusicBee - Grizzlyaudio

Interface 
MusicBee - Grizzlyaudio
Theres no denying MusicBee has a pretty interface. Its simple and quite intuitive. 

The screen layout is completely customatisable for users. Skin and theme customisation are all easy and possible. 


MusicBee - GrizzlyaudioI must say I really like what is on offer. Natively the offering is great, I really found no need to download additional themes to make the GUI usable. Seriously its super good, and in 10-15mins of tweaking you'll have an interface which is tailored to your preferences. 

Sound 

Lets put it out there... MusicBee is not an audiophile player.... Software like Mqn will run rings around MusicBee in terms of pure sound quality.... 
But thats not what MusicBee is about. On the flip side MusicBee would run rings around Mqn, playpcmwin, etc for usability, form and function. It horses for courses! 

Listening via my AKG k712 pro's I find MusicBee provides a nice open mid & top end which is more forward the playpcmwin. A nice benefit it provides headphone users is the native equalisation... which is a must for HeadFi listening. 


MusicBee - GrizzlyaudioIt also must be said MusicBee ensures bit perfect output in the form of Wapasi and/or Asio output. 

External audio & video players

Jplay MusicBee Integration GrizzlyaudioFeel like turbo charging MusicBee's audio performance? 

Well you can. 

MusicBee offers users the ability to integrate alternate video and audio players. 

To test this out I installed a free trial of Jplay.  Which is widely recognised as a leader in windows audiophile software transports.  

Once installed, simply select the Jplay Asio driver as your player output in preferences. Musicbee's player is now bypassed in favour of Jplays highly awarded rendering engine. 

So now you have the best of both worlds! Awesome music management and audiophile quality output. 

Artist info 
MusicBee offers a great artist info and song Lyric function.  
MusicBee - Grizzlyaudio
With web look up for song Lyrics, artist and album info and art work, you'll always have this detail at your finger tips. 



Tagging Tools 
It couldn't be more simple to tag albums and music files in MusicBee. 

Music Bee offers an impressive selection of tagging tools and utilities, offering intuitive auto and manual tagging functions.  


You also get a tag filter which enables sorting based on selected criteria. 


MusicBee - GrizzlyaudioThe MusicBee software will look up web listings for album art and artist info which you can either embed into your music files or save into the directories your music is located. 

A duplication search function is also provided, a nifty tool which enables users to remove file and album double ups. 

MusicBee - Grizzlyaudio

Music Management & Synchronisation 

Secure and accurate CD-ripping is also on the cards. Users can manage & build their music collections quick and easily. Aided by file conversion tools users can convert their music files to the following formats, AAC, Flac, MP3, Ogg, Musepak & Tak. 

With respect to music library creation users can import existing libraries from iTunes and Windows Media Player should this be a requirement. 
Most users will however simply point MusicBee to their favourite music directory on their trusty PC and have it actively monitor for new content... 

For those on the move and lets face it that's pretty much everyone these days.... you also have the option of syncing your music to either Android or iOS devices - your music will always be up to date - pretty cool right. 


MusicBee even provides a portable installer which enables you to install a portable version of the MusicBee software for travel..... See this link. 


Playback Interface Modes 

MusicBee offers 3 modes of interface. 

Normal

MusicBee - Grizzlyaudio



























Compact 

MusicBee - Grizzlyaudio
Mini 
MusicBee - Grizzlyaudio

These modes allow users to control the foot print of the MusicBee interface. 


The 3 options provided give users a varying degrees of control, information and artist detail while they listen. 


Control 

A few options of control exist for MusicBee. 
MusicBee - Grizzlyaudio - apps
The most obvious is via the laptop. 
MusicBee - Grizzlyaudio - apps
The second is headless operation. 

If you like me would prefer to control things from the palm of your hand, head on over to google play with this link.. What you will find is a free android controller which provides headless operation for the MusicBee software. The app provides full library browsing, song selection, album art viewing, all the options one would expect from a headless controller app.


Summary of functionality... Taken from
MusicBee - Grizzlyaudio - apps
1. Basic track information display (artist, title, album, year of release and artwork).
2. Basic player control. (play, pause, stop, next, previous, volume change, mute, shuffle, repeat)
3. Last.fm account scrobbling on/off.
4. Last.fm love/ban.
5. 5 star rating.
6. Playback progress display and control.
7. Lyrics support (Love this!!).
8. Now playing list display, along with the ability to choose a track to play, search for a track to play, remove a track from the now playing list, or reorder the tracks.
9. Library Search support 
10. Option to reduce the volume on incoming call.
11. Lockscreen controls on devices running Android 4.0 or greater
12. Headset controls on devices running Android 4.0 or greater
13. Volume control using the hardware buttons.

To get the app working you will need to head on over to this link, where you will find the plugin for MusicBee to make everything happen. Simply download the self installer. 

Once complete and installed start MusicBee and then open your android app. Go to settings, connection manager, hit scan and select your PC. It's that easy.... 
You now have full headless operation from the palm of your hand. 

Its cool to note both the application and the plugin are open source and distributed under the GPLv3 License. For those with sexy coding fingers you can find the source for the application here, and for the plugin here.  


Friday, August 21, 2015

MiniDSP 2x4 (Analog to Analog) Crossover Implementation

An unbiased user review..... 


I purchased 2 x miniDSP 2x4 balanced DSP's...and a 4way advanced crossover plugin....  to simplify crossover design and implementation for my active speaker build.


minidsp review - grizzlyaudio - DSP

So why did I select the balanced miniDSP processors, over the unbalanced units? Well, I needed a digital crossover which had enough I/O signal voltage to adequately drive a mix of both residential & pro amplifiers.


MiniDSP 2x4 balanced fit the bill nicely, with its ability to accept & output up to +2v signals, a must when connecting the units to pro equipment, such as amplifiers, DAC equipment, which have much higher signal voltage swing capabilities V's HiFi equivalents. 

Early in the piece miniDSP felt like a solid decision, especially considering that throughout my pre-purchase research, it was evident there was alot of user/forum support detailing success with miniDSP units. Many of these users reported there was no audible difference with miniDSP in the chain. Ultimately, this was not my experience with the product. 

What proves frustrating is miniDSP has positioned itself as the DIY "audiophile" DSP solution. A product range which provides excellent transparency and an "uncanny" ability to slip right into your signal chain without any degradation to sound quality, modifications to your system, or introduction of hard to solve idle hiss and/or gain issues. I won't harp on here except to say tread carefully.... 

Don't necessarily believe everything you read. Yes the product has many excellent positives, like price point, convenience, accessibility and forum user support.... however.... yes I did find a but! (especially in my application) it became clear miniDSP also has some considerable shortcomings which may impact its suitability for many HiFi applications. So its worth treading with some caution.

I learnt first hand that miniDSP balanced was not suitable for my HiFi crossover setup. When I dug a little deeper with my online research. I found many users experiencing and struggling with similar application suitability and product issues. 


Before you click on that "BUY NOW" button take the time to google miniDSP hiss, miniDSP sound quality, miniDSP gain issues and you will find real miniDSP adopters struggling with their miniDSP Hifi & 5.1 applications. 

So with the much acclaimed miniDSP units tried and tested in my system, I give you the following unbiased and honest "abridged" account of my time with miniDSP balanced 2x4 4 way advanced crossover solution.


EXPERIENCE SUMMARY 

#1. DSP IDLE HISS 
The miniDSP (Balanced 2x4) has a very noticeable idle noise floor. 

Let me explain.....  I connected the miniDSP 2x4 units between my balanced preamp and various balanced/unbalanced multi-channel amplification stages. I utilised 2 x brand name passive bookshelf speakers (circa 87db efficiency rating) and 2 x high end digital servo controlled subwoofers for testing... both balanced and unbalanced connection tests were conducted - utilising both residential and commercial amplification products. PM me for these details, if you are interested. 

Now if you are like me and run similar pre-amplifier / amplifier equipment and wish to use a single volume control before your miniDSP for attenuation (Your preamp) - you may need to think again. 


Testing various system setups/connections (utilising a pre amp/bypassing preamp), I found DSP idle hiss present on both mid and high frequency speaker drivers. The DSP idle hiss levels were far from acceptable. I have never had high frequency and mid driver system hiss before. I tried several different power supply units, connected at various different wall sockets, however the idle hiss remained constant and present. Power supply changes made no difference to the pitch, loudness or presence of noise. The idle hiss was audible from my seated position some 2.5 meters from my speakers. 


My exclusion tests later confirmed the MiniDSP as the source of the hiss. Why do I say this, because when I tested with no source connected to the miniDSP input.... I.e. miniDSP directly connected to my amplifier (various pro and residential units) signal hiss was unchanged and still present.

These tests clearly prove (at least in my system) miniDSP was the cause/originator of the signal hiss. Removing the miniDSP from the input of both amplifier setups restores dead quite systems. If this is not proof enough that miniDSP balanced is noisy I don't know what is..


minidsp review - grizzlyaudio - DSPIn fact I was so shocked I tried a comparable Extron DMP44LC a commercial grade 4x4 basic DSP which offers a SNR of 100db or greater. This unit demonstrated vastly lower DSP idle noise in comparison to the miniDSP, even when connected utilising the same balanced terminations and leads that just previously connected the miniDSP. Additionally I also experimented with a Symetrix zone mix 760 which also displayed a much reduced DSP idle hiss V's the miniDSP 2x4 in my system. 

minidsp review - grizzlyaudio - DSP

To provide a little background, I tested both 0.9v and 2v input sensitivities with unbalanced and balanced connections. The idle hiss was present with either input sensitivity selection. High end Pro and consumer amplifiers were also tested in the signal chain, which offer varying degrees of input gain (4db-32db). Tests were also conducted with and without a preampliier/source in the system (Direct miniDSP to amplifier connection). 

In all tests the DSP induced idle hiss was present. 

Bypassing the miniDSP (removing it completely from the signal chain) restored my systems fidelity and performance. 


So for me its no secret that miniDSP 2x4 falls short of cutting the mustard as a great sounding DSP/crossover product. In my system miniDSP simply could not perform to acceptable noise free HiFi SNR expectations.

I would argue just because miniDSP 2x4 is convenient (for equalisation/crossover duties), one should not automatically assume it is fit for permanent casual or even critical HiFi crossover applications. The amount of DSP induced signal hiss noise present at idle should be concerning for any potential user looking at analog to analog implementation.  

Look I am a realist so maybe different incarnations of miniDSP do perform to higher quality levels. Or maybe improvements/rationalisation elsewhere in my system could make up for miniDSP 2x4's shortcomings. 


#2. miniDSP CUSTOMER SERVICE 
Just beware its never the product that has an issue, its the implementation.  
At the end of my dealings with MiniDSP I managed to get a refund on my boards, but I had to push very hard. However it was easier to resell the units locally, as return freight overseas was an expense I did not want to incur.  

#3. GAIN ATTENUATION 
It appears the miniDSP 2x4 applies some gain attenuation between input to output at synergy.  

#4. miniDSP DELIVERY 
On a positive note, once ordered the miniDSP units arrived in 5 days!. 
I order them on a Saturday and the miniDSP package was on my doorstep that Friday!! straight from Hong Kong. That's is seriously quick. All items were very well packaged and arrived in pristine condition. 

Previous installation & programming experience with DSP's include:
Clearone, Symetrix, Biamp, Extron, EAW