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[Ken Webster]

Hi,

One of our PCs is failing to play MIDI files.  As it is a very old desktop XP PC, we have decided to replace it and I am tasked with doing so.  However, since upgrading the analogue side of the system last year and as the current digital implementation is poor, I planned to completely redesign the digital side of the system.   This requires a report with proposed spec to be written up for approval.  I haven't put pen to paper as yet but have some ideas and would like some advise.

The current digital AV side has 2 PCs, one primarily for playing music slides and the other primarily for AV content like word slides and video presentations.  We also have a CD/DVD player.  These can all play sound through the desk but only the last 2 connect to the video projector.

We have for many years relied on recorded music in our services but recently some musicians have joined the church and now do some live music.  It is likely we will continue with recorded music for the majority of services.

I would like to combine word slides with recorded music files to release people from projection.  However when we have live music, we will still need to run word slide projection.  I don't believe the sound operator can do both jobs effectively.

The requirement for constructing play lists from digital AV files remains so I am looking for alternative equipment options for constructing and playing the play lists as we do currently with the Desktop PCs using windows media player (audio only).  My concern is that PC have a long standing reputation for poor PSU, internal shielding and high RF and EM interference.  I note, there are some better shielded sound cards available these days.  The PCs have in the past caused issues with ground loop hum.  Possibly this has been due to a combination of things that have been attended too, including isolation using audio transformers.  So I am interested in non PC alternatives if they exist or better ways to set them up to avoid noise issues (inc fans) etc.

I had a brief look at "all in ones" the other day but I don't know how this option compares for sound quality S/N performance etc.  While digital devices generally have internal DACS, I am considering connecting all such devices through an external HDMI control center DAC to drive FOH sound and projection.  This keeps AV output in synch and reduces desk input channels to just 2 (split tracks) instead of the 6 currently used.  This releases more channels for live sound.  It's expensive though!

Any comments or suggestions for things to follow up are most welcome.

Ken

[Scott Holtzman]

Hi,

One of our PCs is failing to play MIDI files.  As it is a very old desktop XP PC, we have decided to replace it and I am tasked with doing so.  However, since upgrading the analogue side of the system last year and as the current digital implementation is poor, I planned to completely redesign the digital side of the system.   This requires a report with proposed spec to be written up for approval.  I haven't put pen to paper as yet but have some ideas and would like some advise.

The current digital AV side has 2 PCs, one primarily for playing music slides and the other primarily for AV content like word slides and video presentations.  We also have a CD/DVD player.  These can all play sound through the desk but only the last 2 connect to the video projector.

We have for many years relied on recorded music in our services but recently some musicians have joined the church and now do some live music.  It is likely we will continue with recorded music for the majority of services.

I would like to combine word slides with recorded music files to release people from projection.  However when we have live music, we will still need to run word slide projection.  I don't believe the sound operator can do both jobs effectively.

The requirement for constructing play lists from digital AV files remains so I am looking for alternative equipment options for constructing and playing the play lists as we do currently with the Desktop PCs using windows media player (audio only).  My concern is that PC have a long standing reputation for poor PSU, internal shielding and high RF and EM interference.  I note, there are some better shielded sound cards available these days.  The PCs have in the past caused issues with ground loop hum.  Possibly this has been due to a combination of things that have been attended too, including isolation using audio transformers.  So I am interested in non PC alternatives if they exist or better ways to set them up to avoid noise issues (inc fans) etc.

I had a brief look at "all in ones" the other day but I don't know how this option compares for sound quality S/N performance etc.  While digital devices generally have internal DACS, I am considering connecting all such devices through an external HDMI control center DAC to drive FOH sound and projection.  This keeps AV output in synch and reduces desk input channels to just 2 (split tracks) instead of the 6 currently used.  This releases more channels for live sound.  It's expensive though!

Any comments or suggestions for things to follow up are most welcome.

Ken

You just need a modern PC with an HDMI or display port.  Delay is adjustable in software so I don't think plucking the audio off the HDMI is the best idea.  You could use the DAC in the projector if it has one and put a DI up the projector and run a balanced line back to the board (1 input, you don't want stereo and should not be running any stereo through the PA.  All stereo sources should be mixed down to mono).


I would personally just run a decent external USB audio interface.  So many good choices in the $100 range.


As far as the PC what's your religion PC or MAC?  You really can't go wrong with anything in the i5 class, dedicated video and 16G of RAM. OS on SSD and a quick large hard drive for media.  On the PC side you should not even need to spend $1000.00 I am not sure what premium those Apple thingies. bring.

[Mac Kerr]

Hi,

Any comments or suggestions for things to follow up are most welcome.

Ken

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Mac

[Ken Webster]

You just need a modern PC with an HDMI or display port.  Delay is adjustable in software so I don't think plucking the audio off the HDMI is the best idea.  You could use the DAC in the projector if it has one and put a DI up the projector and run a balanced line back to the board (1 input, you don't want stereo and should not be running any stereo through the PA.  All stereo sources should be mixed down to mono).


I would personally just run a decent external USB audio interface.  So many good choices in the $100 range.


As far as the PC what's your religion PC or MAC?  You really can't go wrong with anything in the i5 class, dedicated video and 16G of RAM. OS on SSD and a quick large hard drive for media.  On the PC side you should not even need to spend $1000.00 I am not sure what premium those Apple thingies. bring.

I understand this may seem overkill but essentially I want to identify the best performing option, then work back from there to an affordable agreed solution.  So the basic principles are, use the best available source, mess with the signal as little as possible, keep the interconnects short and to the best standard, keep the S/N as low as possible, keep interference as low as possible, keep PSU and earth reference issues minimal.

I agree with the need for HDMI as it's the only interconnect that supports uncompressed lossless HD bitstream.  Delay I have found, depending on device doesn't necessarily work in the way you would like to use it.  It is difficult to predict whether this will be useful to the system you end up with.  It may be more flexible in a PC than other types of AV products.  Using the projector DAC if it has one) effectively doubles the signal cable run and number of connections which is unacceptable.  The mixer output is indeed MONO however the digital files and CDs they were ripped from include some split tracks.  It is necessary to bring split tracks into the board as separate channels so the vocal track can be blended with the stage vocal and then balanced against the instrumental track.  Some of these split tracks are so unbalanced, this is just not even optional, each of the 3 devices that may play split track must input the mixer as stereo.  They never play together so could be selected externally from the mixer provided queuing is available.  To my knowledge, USB does not support an uncompressed lossless audio bitstream (at least in earlier windows versions).  In any case, the only way we can currently switch projection between A/V sources, is by IR remote control which is unreliable at the distance.  This is a major reason that I am leaning towards the HDMI control centre, to switch between AV sources.  However, I have seen HDMI switch boxes which appear to allow AV source switching.  This might allow us to use a single less expensive DAC.  The two less expensive options are functionally the same as a control centre.  I guess part of this is the idea that investing is a single common external DAC should be better value for money than relying on possibly dubious inbuilt ones that are subject to higher noise interference within the PC case.  As to OS, unless there is some clear AV performance difference, windows is the most likely path for familiarity and software availability reasons.  I hope to make all media files available on a local WIFI network so other ministries may access them without booting the main PA but the PA will always have a priority hard wired network connection to them.

Currently, the pressing questions I have are around source device type, the rest is just setting the contextual scene and my current thinking for now:
    Is there a realistic non PC option for playing off play lists?
    Which will give the cleanest sound, Desktop, All in one or Laptop etc?

The last is a big question as it includes power supply and earth reference stability as well as RF and other induced electrical effects, case shielding etc.  I am interested in the all in one PC option as it seems like a light weight computing option and therefore I suspect the PSU might have less adverse effects but it depends how well it's designed and constructed.  For me, these devices are unfamiliar.  I am concerned about this because PCs will share the same power and earth system as every other AV device in the system and in my experience PCs don't share well in this respect as they are not primarily designed too.

Regards,
Ken

[Scott Holtzman]

I understand this may seem overkill but essentially I want to identify the best performing option, then work back from there to an affordable agreed solution.  So the basic principles are, use the best available source, mess with the signal as little as possible, keep the interconnects short and to the best standard, keep the S/N as low as possible, keep interference as low as possible, keep PSU and earth reference issues minimal.

I agree with the need for HDMI as it's the only interconnect that supports uncompressed lossless HD bitstream.  Delay I have found, depending on device doesn't necessarily work in the way you would like to use it.  It is difficult to predict whether this will be useful to the system you end up with.  It may be more flexible in a PC than other types of AV products.  Using the projector DAC if it has one) effectively doubles the signal cable run and number of connections which is unacceptable.  The mixer output is indeed MONO however the digital files and CDs they were ripped from include some split tracks.  It is necessary to bring split tracks into the board as separate channels so the vocal track can be blended with the stage vocal and then balanced against the instrumental track.  Some of these split tracks are so unbalanced, this is just not even optional, each of the 3 devices that may play split track must input the mixer as stereo.  They never play together so could be selected externally from the mixer provided queuing is available.  To my knowledge, USB does not support an uncompressed lossless audio bitstream (at least in earlier windows versions).  In any case, the only way we can currently switch projection between A/V sources, is by IR remote control which is unreliable at the distance.  This is a major reason that I am leaning towards the HDMI control centre, to switch between AV sources.  However, I have seen HDMI switch boxes which appear to allow AV source switching.  This might allow us to use a single less expensive DAC.  The two less expensive options are functionally the same as a control centre.  I guess part of this is the idea that investing is a single common external DAC should be better value for money than relying on possibly dubious inbuilt ones that are subject to higher noise interference within the PC case.  As to OS, unless there is some clear AV performance difference, windows is the most likely path for familiarity and software availability reasons.  I hope to make all media files available on a local WIFI network so other ministries may access them without booting the main PA but the PA will always have a priority hard wired network connection to them.

Currently, the pressing questions I have are around source device type, the rest is just setting the contextual scene and my current thinking for now:
    Is there a realistic non PC option for playing off play lists?
    Which will give the cleanest sound, Desktop, All in one or Laptop etc?

The last is a big question as it includes power supply and earth reference stability as well as RF and other induced electrical effects, case shielding etc.  I am interested in the all in one PC option as it seems like a light weight computing option and therefore I suspect the PSU might have less adverse effects but it depends how well it's designed and constructed.  For me, these devices are unfamiliar.  I am concerned about this because PCs will share the same power and earth system as every other AV device in the system and in my experience PCs don't share well in this respect as they are not primarily designed too.

Regards,
Ken

The PC won't effect the audio quality unless it is it can't push bits fast enough, all can do that.  If you need to adjust levels of stereo tracks to mixdown then you do need a stereo DI.  The HDMI switcher is not going to guarantee audio sync. 


You didn't answer question about board type.


Can you give an example of the type of switcher you are considering?


Whatever PC you choose I think you should use an external USB audio interface that provides proper balanced outputs.  So many options Peavey and Behringer on the load end.  Focusrite makes some very nice units.  Radial has a nice box too the USB Pro-2 that falls in the mid range at about $200.00

[Caleb Dueck]

I believe Scott's point is that any new-ish computer is not going to be the weak link in the chain. 

[Stephen Swaffer]

I have used both PCs and Macs and both desktop and laptop versions of each for media presentations.  I have also used sound card outputs, headphone jacks on laptops and usb and adat interfaces.  The only time I have run into noise issues from ground loops or anything else has been using a sound card/headphone output to run to a mixer.  Using a USB interface as Scott suggests has always been a clean interace for me.

For the money, I'd rather have a PC than a Mac-the Mac's are just a pain if you want to do anything other than what Apple wants you to do-or assumes is the best way and I just can't see paying more for that inconvenience.  From a practicle standpoint, PC's can be just as reliable.

[Ken Webster]

The Mixing console is a Yamaha MR1642.  I know these are getting long in the tooth but it’s working fine especially after deoxiting all the connections and lubing all the faders and pots.  There are 2 failed faders that lube spray won’t bring back to life but the leaves 14 other viable channels so not much of an issue.  It should be replaced sometime but this is not as urgent as the PC not playing the MIDI files.  The PC still plays the ripped files which is the majority of what we use.

I have not put together any short lists of HDMI switches, DACS or control centres.  So far, I am not considering any specific product brands or models.  I have only identified that such devices exist and could potentially meet the purpose.  The following are just some examples.

HDMI control centres:
    Essence HDACC II     http://www.essenceelectrostatic.com/hdmi-v2-0a-is-not-forward-compatible-with-earlier-versions-of-hdmi/essence-hdacc-ii-4k-front-2/
    AU-D250-4K22    http://www.cypeurope.com/store/store/app/product/AU-D250/Advanced-Digital-Audio-Converter-
    Just ignoring the ridiculous price for a moment, I can’t help but notice the case similarity here.
    OK so just ignore the prices for now, they are just examples of a single package solution.

Here is a 2017 review of HDMI switchers:
http://www.toptenreviews.com/electronics/tv/best-hdmi-switchers/

HDMI switch could be combined with an HDMI pass through DAC.
Although these examples are unbalanced, the cable run is only a few cm (not sufficient to pick up noise).
http://www.essenceelectrostatic.com/product/evolve-hdmi-multi-channel-dac/
http://www.lindy.com.au/4k-hdmi-audio-extractor-with-hdmi-pass-through
http://www.lindy.com.au/4k-hdmi-audio-extractor-with-mhl-arc

Here is one that provides balances analogue out:
http://www.extron.com/product/product.aspx?id=hae100&subtype=361&s=4

So it appears an HDMI switching approach may be possible at least.
If so, it looks likely to be a very simple to operate solution for us.

I know that many people think that digital is just about the bits.  So I ask, is a PC going to give the same performance as say an OPPO BDP?  I am aware that PSU design and construction is important for audio performance even in digital gear.  This is why I am asking, to see if the PC industry has lifted it’s game or have we simply given up?  I am not very satisfied with, don’t you worry about that……

I just don't want the benefits of future upgrades to be limited by what we do now.


Ken

[Stephen Swaffer]

So check out the websites for QLab and Ableton Live-and search threads on here.  There are plenty of guys using these software packages in much more demanding applications than you probably ever will use in your current situation. 

As Caleb and Scott have said, the computer is not going to be the weak link.

USB 3.0 can stream 32 channels in both directions simultaneously to our QU-32, 48 kHZ, 24 bit.  A couple of stereo channel's isn't going to make it work hard.

In H.O.W, keep the signal chain simple and if you are concerned about the DAC, buy a USB interface that is designed to be a pro level DAC with true balanced outputs-not a home theater consumer piece of gear.

Just my opinion.  Have I used consumer gear in our church?  Yes-and it usually does OK-but it also tends to act up at the worst possible times.

[Cailen Waddell]

There seems to be a lot of hardware talk.   That seems backwards to me.  Find the software that best supports your needs then get the hardware recommended by the software manufacturer. 

If you are playing slides and pre recorded music qlab and pro presenter are packages you should look at.   There may be others.


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