Adding Digital processing to an analog console

[DiscoBoxer]

I wanted to do a feeler to see if anybody has experience with this....with positive results.

I am exploring adding digital processing, using an outboard computer with various software options, and using the "inserts" of an analog console to process the source(s).

I imagine that there are latency issues with this style of processing and if anyone has had useable results in a live sound setting? Maybe there are other suggestions for the outboard processing, that allows a lot of options for multiple channels, without having to purchase many racks or hardware.

Purchasing/rental of a digital console is not an option for this exercise. Console is GL3800.

 

[Ric]

Latency from any digital system is an issue, and will vary from device/software; unnoticeable to very noticeable.
You are likely to find that the cost of processing per channel for the computer path may far exceed using individual dedicated outboard processing, i.e. standard effects units, noise gates, compressors etc.

 

[Eboy87]

Honestly, I would be interested to see the cost breakdown of this. Yes, you will have latency issues depending on what you use for processing. How noticeable the latency will be depends on the gear you're using. I've heard of people using a PT HD rig to decent effect, but that's gettign up there in the dollar department. On the other hand, I've used a DriveRack 260 to great effect when needing some parametric filters and a limiter. XTA used to make a dynamics processor specifically to be inserted on the channel rather than the out. It worked well, but the menu had to be accessed via computer to be of any use. We had ours going through a hodgepodge of adaptors to be wireless, and it would die at the most inconvenient times.

Essentially, you're real problem are the number of analog to digital conversions, and vice-versa. That's where your latency issues develop. With something like Peavey's Media Matrix, it's not a problem, as you have one DA/AD. I would say to just spend the money on a few 8-channel Presonus dynamics processors and TC Electronics D-2 and M-1, but by all means, experiment a bit. There's nothing like trying it for yourself to gain more experience and knowledge. May I ask, what the application of this will be?

I hope some of that rambling made sense.

 

[cmckeeman]

i have done this using a behringer board, ardour as the DAW and used the plug in's throguh it and a Safire pro 24 i couldn't tell any latency issues (but i was using it to split and delay the signals) and besideds the interface and a decent mac there are no other costs in making it happen.

 

[65535]

At best the Saffire Pro 24 has 4 analog inputs that alone is $75 per channel of processing. Plus software and a computer.

 

[museav]

There is latency in the A/D and D/A conversions but also in the actual signal processing in the computer and factors such as sampling rates and buffer sizes will often affect the overall latency, so it is difficult to say since the latency would be interface, software, computer and application dependent. Adding to that is the actual processing applied and the application, for example if you are trying to delay a signal with the processing then some latency may not matter and might simply reduce the additional delay required, however if you were trying to mix the processed signal with an undelayed direct, unprocessed electronic or acoustic version of the same signal, then any latency may be a concern.

Also consider that all latency in delivering the signal is potentially additive. For example, if a listener is 10' from a vocalist and 30' from the speaker then the audio from the speaker is already 20' or 17.7ms behind the natural sound. If you have a system DSP that may add a few more milliseconds. Now you're getting where 10ms or so of additional latency may make the sound from the speaker be perceived as separate from the direct sound or essentially as an echo. This can get to be an issue for house speaker spill to performers on stage as well, there often near the actual source but some distance from the speakers and thus much additional latency in any sound the performers hear from the house speakers may start throwing them off.

 

[DiscoBoxer]

I have seen and worked a lot of churches where large format analog consoles are in use, with very limited to no outboards. Common to see 2-6ch of Limit/Gate/Comp (mostly just comp), one multi effects processor, BBE Sonic Maximizer (Great job on the marketing, BBE) and very limited EQ on console. At best, I have seen all the VCAs covered with maybe a few aux sends/returns. A lot of the churches will have one or two decent computers near by, with some familiarity with post production NLEs.

Even though we are seeing more players in the digital console offering trying to meet the demands of small venues on a budget, there is still a gap. My curiosity is on the possibility of creating a hybrid option for those venues that use a lot of channels, lack the current inventory in outboards, and are not at the stage to trade in their analog consoles. I wouldn't be able to accomplish the benefit of saving scenes, but I entertain the thought of dealing with just processing.

I think it would be a fun and educational exercise to see what could be done. Even if the cost ends up being high (subjective), comparable to outboard racks, its doubtful that the racks would ever have the flexibility of options that a stand alone computer could offer with limitless plugins & software options. For the most part, I might run it as a mobile option when I am engineering.

Confirmed by comments above is the issue of latency. Would a firewire I/O work better than a high quality mass I/O sound card due to it's committed resources for A/D conversion?

I have been looking at the Focusrite Saffire Pro 40 or 56 as a starting point....at current pricing, it will cost me about $12 per ch, not including patching from console to processor.

Another possible benefit is for venues with horrible acoustic treatments. Many want to produce a distributable copy of the mix, and taking a record off the mains is not sufficient since the mix is manipulated to accommodate the room and system interaction. Using fly mics has the inherent problem of reintroducing the room's reverberant effect. With an outboard interface to a computer, one might produce a better quality record for live venues, without being limited by tracks.

Thanks for the feedback thus far, keep it coming!

 

[museav]

I have seen and worked a lot of churches where large format analog consoles are in use, with very limited to no outboards. Common to see 2-6ch of Limit/Gate/Comp (mostly just comp), one multi effects processor, BBE Sonic Maximizer (Great job on the marketing, BBE) and very limited EQ on console. At best, I have seen all the VCAs covered with maybe a few aux sends/returns. A lot of the churches will have one or two decent computers near by, with some familiarity with post production NLEs.

Even though we are seeing more players in the digital console offering trying to meet the demands of small venues on a budget, there is still a gap. My curiosity is on the possibility of creating a hybrid option for those venues that use a lot of channels, lack the current inventory in outboards, and are not at the stage to trade in their analog consoles. I wouldn't be able to accomplish the benefit of saving scenes, but I entertain the thought of dealing with just processing.

I think it would be a fun and educational exercise to see what could be done. Even if the cost ends up being high (subjective), comparable to outboard racks, its doubtful that the racks would ever have the flexibility of options that a stand alone computer could offer with limitless plugins & software options. For the most part, I might run it as a mobile option when I am engineering.

Makes one wonder how people ever managed without full signal processing on every channel!

Seriously, I understand what you are going for but the reality is that many of the churches that fit that description are also lucky to have people that can create a decent mix as it is. So while I can see some applications, they may be limited. Quite frankly, anyone willing to invest in and routinely use external interfaces, a computer and software for live processing may just look at SAC - Software Audio Console as that seems to do everything you want without the associated latency issues.

FWIW, another potential issue with using the channel inserts is where they occur in the signal path and whether you can do things such as have an unprocessed signal for monitors and a processsed signal for the house mix.

Confirmed by comments above is the issue of latency. Would a firewire I/O work better than a high quality mass I/O sound card due to it's committed resources for A/D conversion?

On another forum someone recently asked about using a particular software for a similar application and upon reading about it I found that it was 'able' to get its latency under 25ms. That may be acceptable in production and recording applications but not in live sound and while that is probably unusually high, that is just the software processing latency without any A/D and D/A latency added.

When you think about it, a digital console and even an external audio DSP device are pretty much a 'computer' performing processing on digital audio signals with many having analog inputs and outputs and the associated A/D and D/A conversion. The difference is that the related software, firmware and hardware are all dedicated to that one purpose and thus can be optimized for each other and for that specific use. In comparison, a PC or Mac being used for audio is much more a general purpose device with third party audio interfaces and running third party software that is typically intended for applications other than live sound. It can do the job, just generally not nearly as effectively as a dedicated device. Software Audio Console or SAC is sort of a hybrid that uses a PC, external third party audio interfaces and third party software, but essentially applies them in a manner that creates a dedicated purpose 'device'.

Another possible benefit is for venues with horrible acoustic treatments. Many want to produce a distributable copy of the mix, and taking a record off the mains is not sufficient since the mix is manipulated to accommodate the room and system interaction. Using fly mics has the inherent problem of reintroducing the room's reverberant effect. With an outboard interface to a computer, one might produce a better quality record for live venues, without being limited by tracks.

Similar to the above, many applications that need to be considering processing for multiple input channels may not simply use the main mix output for recording feeds, but multitrack recording is very different than live signal processing.


Added: I want to be clear that I am not trying to discourage anyone from trying things for their own education or experience and really more addressing why the concept of external PC/Mac based audio processing is not common or addressed by numerous commercial products.

 

[pmolsonmus]

As usual Brad's advise is spot on. Before considering this think about your overall costs. Computer, operating system, software plug-ins (if they're free you usually get what you play for and you're better off with a second hand outboard units (lots on ebay) latency, upgrade to new systems - Firewire is great, but most laptops are not even shipping with with firewire anymore. Apple and others are moving to Thunderbolt (some great options) but they will be getting pricey as you chase that elusive digital computer alternative. A hybrid for audio/video is likely to appear in the future and digital/analog summing is probably going to happen for live issues as it is being used in recording now, but I don't think we're there yet.
Recording is a VERY different beast than live sound, as neat as it may be to control in the box, for critical situations I believe it is either a digital console or an analog console with outboard digital effects. If you're going to invest, consider starting with digital preamps that can be sent via CAT-5 cable. It may make your later purchase less expensive.
YMMV

Phil

 

[FMEng]

Processing to do what? There's a big difference between vocal processing, such as reverbs and plates, and processing like crossovers, house EQ, driver protection limiting, etc.

 

[DiscoBoxer]

Processing to do what? There's a big difference between vocal processing, such as reverbs and plates, and processing like crossovers, house EQ, driver protection limiting, etc.

Signal Effects to Vocals & Instruments, Expanded EQ beyond console limit, compression, gating, limiting per source.

 

[DiscoBoxer]

Makes one wonder how people ever managed without full signal processing on every channel!

Haha yes, but even 20yrs ago, the desire to do what we can do today was still there.

Quite frankly, anyone willing to invest in and routinely use external interfaces, a computer and software for live processing may just look at SAC - Software Audio Console as that seems to do everything you want without the associated latency issues.

Interesting option. I will have to research the stability of the software. I don't think I would want all my controls to be software though. I do see churches that do have some decent computers with some basic I/O options for both audio and video post editing.

FWIW, another potential issue with using the channel inserts is where they occur in the signal path and whether you can do things such as have an unprocessed signal for monitors and a processsed signal for the house mix.

Good point in regards to vocal and instrument effects, but I would not see a problem if a channel was being processed for compression/limit/gate, and still routed to both.

On another forum someone recently asked about using a particular software for a similar application and upon reading about it I found that it was 'able' to get its latency under 25ms. That may be acceptable in production and recording applications but not in live sound and while that is probably unusually high, that is just the software processing latency without any A/D and D/A latency added.

I spoke casually with an Engineer from Avid, and his belief is that with a sufficient, current multi-core computer that is dedicated, via firewire, latency should average about 2.1ms......depending on software, and my example with him was WavesLive. If this is true, I think that it is useable in live production. But, experimentation will have to validate if the latency is so low on just 1ch processing vs. 12ch, vs. 24ch, etc.

Similar to the above, many applications that need to be considering processing for multiple input channels may not simply use the main mix output for recording feeds, but multitrack recording is very different than live signal processing.

You are correct about multitrack recording being a different animal. I spoke (typed) incorrectly because I was exhausted at the time of the post.

Added: I want to be clear that I am not trying to discourage anyone from trying things for their own education or experience and really more addressing why the concept of external PC/Mac based audio processing is not common or addressed by numerous commercial products.

I appreciate your input as always Brad, no offense taken. I would challenge that it is not being addresses by numerous commercial products. Albeit, most of the "hardware" options dedicated to the software applications for such are very expensive due to what you mentioned above, that hardware components in these devices are dedicated to a fixed task for efficiency. The latest trend in "micro-digital" consoles being offered are showing the desire by the budget consumer to have "digital" capabilities in live operations. It is discussions such as this one that gets the ball rolling with an individual who may want to introduce the next flexible product.....(Not that I am that guy, LOL!)

 

[FMEng]

The cost of good quality, sychronizable, PC audio cards is pretty steep. You can't do what you want to do with run of the mill sound hardware because most sound cards will not work together in multiples because they are not clock synced together. Unsychronized cards running together will crash the computer. A Digigram VX882 will work in multiples, and has 8 inputs and 8 outputs, costs around $2,300, and that doesn't buy any software or the computer itself.

For that kind of money, you can buy a whole flock of analog boxes and a digital speaker processor. The result will be more stable, take less space, easier to check and adjust on the fly, and won't produce large amounts of fan noise and heat. Not to mention analog will sound better than software that cuts corners either due to cost or to save on processor cycles. No, give me a good analog box with meters, knobs, and switches any day.

 

[DiscoBoxer]

FMEng, after doing a little bit more research, I have come to the conclusion that sound cards are not the way to go for the reasons you brought up.

Now just looking at outboard conversion and transfer via firewire, using something like the Focusrite Saffire Pro 40 or Liquid 56.

While I talked about options for small to mid-size churches/venues, that really is what led me to want to just experiment with an entertaining and educational challenge. I already have a couple powerful computers, both PC and Mac. I have ProTools and Waves as well as a few other software products. The additional investment for me is just in the interfacing at this moment......unless I get someone to compel me that it's totally not worth the effort because latency is going to be a major problem. Right now, its looking like a 2.1ms latency is worthy of a trial.

 

[museav]

Interesting option. I will have to research the stability of the software. I don't think I would want all my controls to be software though. I do see churches that do have some decent computers with some basic I/O options for both audio and video post editing.

Talking with numerous users, the SAC software seems to be quite stable providing you properly setup and configure the machine running it, which includes disabling or shutting down many of the background programs and resources that a PC normally runs.

You can also use MIDI fader packs and controls with SAC, some people seem to not be comfortable without physical faders while others actually seem more comfortable using a mouse and/or touchscreen. I find this interesting since it is usually virtual rotary controls that are more of a problem for me to work with than virtual faders, although on both there is no way to recreate physical aspects such as resistance, stops or detents for a mouse or touchscreen virtual emulation other than your finger running off the screen or your mouse off the table.

One of the challenges with any computer based mixing or processing approach is that much of the potential cost savings and flexibility is in being able to choose the hardware, software, peripherals, interfaces, etc. used. However, this also means that every 'system' is potentially unique and someone has to design a system, purchase the components, put the system together, support it, update it, etc. If you have an audio processor that consists of a PC, monitor, audio interface, software, etc. then somebody has to put all of that together and if something does not work or breaks you can't just take send the 'audio processor' to the factory repair center. Similarly, a dealer, contractor or installer dealing with such a device would not be providing a box but rather a system of multiple boxes. It's interesting to see people talk about how their SAC system cost so little compared to a digital mixer but much of that is because they don't assign any value to the effort they invested. Imagine what a Digidesign Yamaha, Soundcraft, A&H, DiGiCo, etc. would cost if the people designing, building and supporting them all had no cost, but that's not reality.

There was a company in Australia that was working on a mixing console controller that would work with Peavey Nion, BSS and other audio matrix DSP boxes to create a digital live sound mixer, but they seem to have abandoned that effort and focused subsequent development of the consoles on only DAW applications.

 

[neotrotsky]

All very good points, but one question that comes to mind is not as much "How" but "Why"? Sometimes it's actually more cost effective to get off board console units than to go through a PC/Mac if you're just going for something as simple as compression and reverb. Many of the religious services I have worked with who lease our venue want a TON of processing and everyone wants to sound like Whitteny Houston, when in fact all they need is someone who can PROPERLY set a mix and just add a touch of reverb to not make it so dry. Also, I've seen the more people have access to cheap and easy PC based processing (especially with a good FireWire interface) they tend to turn into plugin whores who just soak the signal because they can.

I mean, if you have a specific project or set sound in mind, go for it and don't let me stand in the way! But, perhaps looking at what you want in your final product could help determine if you really want to fight the uphill battle in dealing with a DAW's potential issues. As FNEng said, sometimes Analog is your friend and less CAN be more.

 

[museav]

Many of the religious services I have worked with who lease our venue want a TON of processing and everyone wants to sound like Whitteny Houston, when in fact all they need is someone who can PROPERLY set a mix and just add a touch of reverb to not make it so dry. Also, I've seen the more people have access to cheap and easy PC based processing (especially with a good FireWire interface) they tend to turn into plugin whores who just soak the signal because they can.

While it does not really affect the potential benefit of such tools, I do indeed see this as an increasing issue. People encounter a problem or undesired result and immediately start looking for some processing to insert to fix it rather than trying to understand what is happening and addressing the root cause. They tend to want to always add something rather than considering potentially reducing or eliminating something else. You provide gates and compression on every mixer channel and some seem to perhaps assume that they wouldn't be there if they weren't all intended to be used all the time rather than understanding that they are there in case they are needed. It's great to have such tools available and in the hands of a good operator they can be invaluable, but their becoming so widely available seems to have lead to many people effectively trying to run before they learn how to walk.

 

[neotrotsky]

I actually had an incident where an A2 was learning how to run the board for a major religious event, and had to contend with a singer (who was actually rather good) who just BELTED out everything she did and her level was all over the place. The moment she stepped up to the mic I knew what to expect, but he did not. Within the first few seconds, his hands went not for the channel gain, but to the compressor! I literally had to smack his hand away from the unit and told him "Reduce your ceiling first!". Eventually he broke the habit and looked to his channel strip first before resorting to effects and compressors

 

[DiscoBoxer]

In mid sized churches, talent can be all over the map, from very well trained and experienced to barely useable. Resources can be quite limited and you try to produce the best results with what you have to deal with. Having a powerful vocalists with poor mic control is an easy issue to deal with than say a potentially powerful vocalist who lacks confidence. They may be hot at one point and barely audible at others. You can teach them mic control, adjust their monitors all you want, but they will never become refined without time and experience. In the mean time, using heavier compression to produce a more consistent signal is useful. Same with a Bass guitar player who never really learned the fundamentals and wants to play like Les Claypool. If the problem is the source and you are limited on what you can accomplish in one or a few sessions, but have to use them anyways, then you do whatever you can on your part to assist their signal to become more useable. In very rare circumstances, you can even disguise a poor source with creative effects....but that's not really my goal.

In this "experiment", I am not looking to fix acoustic issues, poor system design issues, or analytic capability of a sound engineer. I'm looking to add tools to the toolbox on capability. I get your point on "plug-in whores", and I have seen my share of it as well as personal experience trying to exploit it, but that is no different than someone overusing outboard effects either. I see way too many people overusing delays & reverbs.....or using them improperly..(more with delays and timing), but truth be told, it's a creative environment, and beyond intelligibility, it's in the hands of the creator(s).

I see the mixing console as an instrument. Some people overplay their instruments and take away from a song, some people play steady and consistent but offer no dynamic variety to the song, there is a balance.

Many mid-sized churches do not have large budgets for mic selection, quality active DI boxes, quality compressors, and effects. Some of the effects offered via "plug-ins" can simulate equipment that is not in the budget realm of these venues. Using Waves, I would love to incorporate some of the compressor options over a common 166xl....any day. There is a creative element in the subtlety these plugins can offer when used "properly".

I would love to have the vocal effects options I have from Waves vs. a cheaper Lexicon with the same old same. I have heard the argument both ways, and I am not the biggest fan of being closed minded and do what has "always" worked. I have the time and the capability to experiment, doesn't matter so much as to why I want to do it, other than I want to try something new and see what I get.

This post was meant to be an exercise in experimenting with a potential tool, not to determine if I need an education in acoustics, system design issues, field experience, or how to even use processing. I appreciate the feedback, but my goal is on the "how" and not the "why". Please forgive if my post sounds defensive, that is not my intent. I do however want to get the post back on track to it's purpose.

Respectfully, thanks!