How to replace your home theater pre-pro with a HTPC!
In a previous blog article – deconstructing the home theater pre-processor – we introduced the idea of replacing the pre-pro with a home theater PC (HTPC). This post provides the meaty details of how we did exactly that!
Overview of the system
Our media server HTPC build is based on the CAPS Zuma but uses a larger chassis with an optical drive to allow DVD and Blu-Ray ripping and playback from optical media. It is a silent PC using heat pipes to cool the processor and contains no fans. We are using a Lynx AES16e card with external DACs from DEQX (the HDP-4) and a Metric Halo (the LIO8).
Hardware bill of materials
Most of the parts are the same as the CAPS Zuma so please see that article for product links.
- Case: Streacom FC10. This is a larger case than the CAPS Zuma with space for two expansion cards and a slot loading optical drive. Two expansion cards allows use of the Lynx AES16e 16 channel digital output card and either a USB card like the SoTM or a video card.
- Motherboard: Intel DH77EB.
- Processor: Intel Core i7 i3770S.
- Memory: Crucial 8GB DDR3 1600.
- SSD: Samsung 840 Pro 120GB.
- Power supply: picoPSU-160-XT + 192W Adapter Power Kit. This is a larger power supply than used in the Caps Zuma and requires the power entry on the rear of the Streacom case to be enlarged using a drill.
- Expansion card: Lynx AES16e. This is a 16 channel PCIe to AES converter.
- Expansion card riser: Logic Supply flexible riser.
- Optical drive: slot loading blu-ray, whatever you can find. I used a TEAC.
- Cables: a couple of special cables are required a) the cable included
with the picoPSU is too short to reach across the case so I had to
extend it using crimp connectors and a short lengths of hook up wire b) the slot load optical drive requires a SATA to miniSATA and power supply adaptor cable.
The build part 1 – installation of the motherboard, processor and heat pipes
The build part 2 – installation of the power supply, RAM, SSD, optical drive, Lynx AES card
With the hardware done it was time to move onto the software. The bill of materials is as follows:
Operating system. All computers need an OS and a HTPC is no different. Windows rather than Linux is the way to go for a HTPC, mainly because we want to use cool applications like JRiver Media Center! I used Windows 8 Pro 64 bit for two reasons: firstly it can back up itself over a network, which lesser versions of the OS cannot and secondly that it includes remote desktop. As a side note having an optical drive like we do in this build makes it much much easier to install Windows 8. Installing it from a USB drive is a royal PITA!
Playback software. Once the OS is installed two key pieces of software need to be installed. The first of these is JRiver Media Center v.18. This amazing library management and playback application is the only way that I know of to replace a pre-pro with a HTPC. The other two pieces of software needed are SlySoft’s AnyDVDHD which allows you to playback and rip blu-ray discs and ArcSoft’s TotalMedia Theater for the dtsdecoder.dll (a file that allows JRiver to decode DTS-HD audio – see here for more details).
Once you’ve installed the software it’s time to move onto configuration!
Windows 8 optimization
Very little optimization is needed to Windows 8 especially when you are using a SSD, 8GB of RAM and a kick ass processor! SweetWater have provided a nice guide written for Windows 7 – but applicable to 8 – that I used to tweak a few settings.
Now we get to the meaty part! JRiver has SO many settings that it is all a bit daunting at first, even for a professional like me! Many of the settings are not that well documented either, which doesn’t help the setup process either. I left most of the general settings untouched except as follows.
In the Tools>Options>Audio menu I changed the following:
- Audio Output: select ASIO as the “Output mode” and then in “Output mode settings”
change the buffer size to 0.1s and check “Device only uses most
significant 24bits”. The Lynx only uses 24 bits even though it is presented in a 32 bit wrapper and that’s why this setting should be checked.
- Volume: set “Volume Mode” to internal and turn on “Volume Protection”. See this wiki article for more. Changing the volume mode lets you use JRiver’s volume control to set playback level and is required for our system topology using external DACs.
- Settings: check “Play files from memory instead of disk”. This is a setting to optimize audio file playback, as far as I can tell it does not affect blu-ray playback.
- Track Change: set “Switch tracks” to Standard (gapped) – 0.5s instead of the annoying cross-fade it is set to as default.
In the Tools>Options>Video menu I changed the following:
- General Video Settings: change video mode to “Red October HQ” (see here for more information), check “Videoclock” (more) and turn “Adaptive Volume” off (set to low by
default). Adaptive Volume seems to be a form of volume compression intended to be used for late night listening…quite why this is in video settings I am not sure about given
that it is an audio parameter!
The next part of the setup is particular to our home theater demo room where the system is installed. I’ll show you the details but just bear in mind they will be different for you if you decide to setup a HTPC of your own! These settings are accessed as follows: Tools>Options>Audio>Settings>DSP Studio. Using JRiver gives you an insane amount of flexibility (way more than all the pre-pros I know of except maybe the DataSat RS20i) in terms of how you want to setup your system.
1) Output format
First we need to properly set the number of output channels. In our home theater demo room we need 12 output channels. This is because the left, center and right are all bi-amplified (i.e. 6 channels), then we have both side and rear surround speakers (another 4 channels) and four subs arranged in separate front and rear arrays (2 more channels). The closest JRiver setting is for 16 channels, which works fine in our case since we have a Lynx AES16e! The big benefit here is that everything is kept in the digital domain. With a normal pre-pro and the screen channels we would need to have an additional DSP box like a Xilica XP3060 after the pre-pro with the resulting extra cost, cabling complexity and potential for sound quality reduction due to the additional analog-to-digital and digital-to-analog conversions.
Most blu-rays only have two surround channels (i.e. they are 5.1) but we have four physical surround channels and so we need to somehow create these extra channels. On a normal pre-pro we would enable Dolby Pro Logic IIx to synthesize the extra surround channels. JRiver does not have Pro Logic IIx but it does have a proprietary upmix algorithm called JRSS. Unfortunately there is precious little information on how JRSS actually works but it does it’s job nicely.
2) Room Correction
This is the part of JRiver where bass management settings are controlled. It is also possible to set speaker levels and delays here but we are doing that in the Parametric Equalizer simply because it’s easier to precisely set individual delays there rather than using the typical pre-pro concept of entering everything as a distance and then having the software work out individual delays. If we are honest the name “Room Correction” is misleading…it’s more like speaker configuration. We’re not doing any room correction here!
In our case we are crossing over the Procella P610 screen channels at 40Hz to our subwoofer array. The P610s are ‘full range’ speakers but we like to rolloff the lowest octave to increase system headroom, lower distortion and improve overall clarity. The surround speakers are P6s which have been designed per THX specifications i.e. they have a characteristic 12dB / octave rolloff below 80Hz.
Jriver’s bass management flexibility is amazing – way, way more than you get in all the pre-pros I have used. Most pre-pros use a fixed 12dB / octave high pass and a fixed 24dB / octave low pass. Since most speakers are not designed as per THX specification this can and does result in imperfect crossover integration (for more see this article). JRiver let’s you perfectly setup bass management every time.
3) Parametric Equalizer
Finally we have what I think is JRiver’s crowning glory – a hugely flexible parametric EQ system built right into the application. In our high end home theaters (and two channel systems too, given a chance) we always specify in and calibrate a parametric EQ to dial out the last remnants of room mode resonances remaining in the low bass after passive acoustic treatment. This normally involves using an outboard EQ like a aforementioned Xilica with the extra cost, wiring complexity and potential for signal degradation it incurs.
We are using the parametric EQ to set levels, delays, add crossovers for bi-amplification of our Procella P610 screen channels and the like. See below for some of the details!
Intel display driver settings
For the video part of blu-ray playback we are using the Intel motherboard’s HDMI output. The settings for this are managed via the Graphics Properties. Out of the box a lot of ‘visual enhancements’ are turned on which will screw up our picture so it is important not to skip this step. Here are the things we changed:
- Resolution – set to 1920x1080p, 60Hz.
- Display > Monitor / TV settings > Enable “IT Content”. This turns off any processing within the Intel display driver.
- Display > Color Enhancement > Enable “YCbCr”. This forces video levels to 16-235 which is the consumer standard used in most displays. If your display supports 0-255 then you could leave this unchecked.
- Media > Image Enhancement > Change “Noise Reduction” and “Sharpness” to application settings, turn off “Skin Tone Enhancement”, “Film Mode Detection” and “Adaptive Contrast Enhancement”.
Lynx mixer panel configuration
To get JRiver’s software outputs to the right physical outputs on our Lynx card we have to do some tweaking to the routing in the Lynx mixer panel. The panel is confusing and mislabeled but eventually we got there!
Other settings that were changed:
- Settings>Buffer Size – reduced from 1024 to 64.
- Settings>Advanced – disable “Synchrolock”.
- Settings>Driver Options – disable “Topology Driver”. This solved an issue where on computer restart the left and right channel volumes in the mixer would reset to -22dB.
Physical hookup of the HTPC to display and DAC
- Video – HDMI from the Intel Motherboard to the display or in our case a Lumagen XS video processor and then onto our SIM2 projector.
- Audio – the Lynx AES16e uses a DB26 connector which is something you don’t see often but does have some advantages in terms of the amount of conductors it packs into a small form factor. To hook it up to our DEQX HDP-4 and Metric Halo LIO8 we had custom cables made up by Redco. The DEQX cable is a DB26 to XLR cable and the Metric Halo cable a DB26 to DB25 cable.
The HTPC in use
It was a lot of effort to determine the proper way to configure everything but I think it was worth it. The system plays back blu-rays flawlessly and the audio DSP works as intended. Sound quality is way better than with a basic pre-pro and the video quality is on par with a nice blu-ray player. There are no pops, clicks or any other nasties to give away the fact you are using a PC. CPU utilization is around 13% and memory utilization 18% when playing back a blu-ray. The system should have plenty of headroom to allow me to experiment with and run multi-channel room correction algorithms from Dirac Live or Audiolense.
Whilst I was configuring JRiver I came across a great additional feature called Zones. This allows you to setup multiple profiles, each of which can comprise a completely different JRiver configuration. The really cool part is that you can get JRiver to automatically switch between profiles using ZoneSwitch depending on what content is playing. In my case I have setup my system so that 2 channel music goes out of the PC into a USB/SPDIF converter and then into my DEQX. I found this to have better sound quality than the Lynx AES16e. When I pop in a blu-ray disc (or play back from a disc stored on my NAS) then JRiver switches back to the Lynx AES card. This means that the HTPC has also become our music server for playback of both redbook and hi-rez music. Bye-bye Mac Mini, iTunes and Pure Music (we won’t miss you!).
What do you think about our HTPC experiment? Please gather your thoughts and add a comment below!
The HTPC as pre-pro replacement was an interesting project, but we found a number of issues with it:
- Limited to sources originating on the computer (can’t switch external HDMI sources)
- High complexity (many JRiver settings to fiddle with)
- Average reliability (updates to JRiver or Windows stop the system from working, requiring manual interventions)
- Poor usability (don’t expect other family members to be able to use it)
- No Atmos or DTS.X decoding