Latency free monitoring solutions

For all their many advantages, DAWs have one serious disadvantage, latency. As we know, latency is the time delay created by the finite amount of time it takes for digital processes to execute. This is true for any audio processor including A to D and D to A convertors, effects processors and digital mixers, but in the case of these devices the latency is within the time frames of that which occurs naturally as sound travels through the air. In short, it's all but inaudible.

The story is different for a DAW. In the case of the round trip latency between a DAWs input and output,  the delay is compounded by the need to buffer samples until processor time becomes available. This i/o buffering is what causes performers the most problems when we are monitoring the DAW output. A delay of more than 30ms can be off-putting to many performers, especially guitarists.

i/o buffer settings in a Logic project

There are a number of solutions and all have advantages and disadvantages.

1) Direct out audio interface monitoring. In this case, the audio interface duplicates the input signal before conversion and passes one copy to the A to D and the other back to the stereo monitor output. This process is analogous to a tape recorder's input-copy-monitor function (see this video on tape delay).

However,  because the recording of the performance is not being monitored, any problems will not be evident until playback. This is why playback was such an essential part of multi-track tape recorder recording.

A second disadvantage is that any effects or processing applied to the signal (track) in the DAW will not be heard. Some audio interfaces offer a monitor reverb which is added to the direct out signal to help blend the performance with the backing track.

If you plan to use this approach, you must ensure your audio interface software provides suitable tools for balancing monitor mix levels, especially if you are recording many performance simultaneously (eg tracking).

2) Reduce the latency to the lowest possible sample count by optimising the DAW system and turning off any latency inducing processes during recording.

This method can be tedious, often requires a software and/or system re-boot and is not always successful in reducing latency to an acceptable level.

3) Turn-off software monitoring in your DAW,  split/duplicate the signal to be recorded and send one to the audio interface and the other to a spare channel on a separate hardware monitor mixer which is also monitoring the DAW stereo out. You can add hardware effects reverbs to the mixer's send and return or buy something like a Yamaha O1V which has effects in-built.

This solution requires more hardware (much of which is dirt-cheap on eBay), including a mic/line level splitter, but may ultimately be more scalable, flexible, easier to configure and intuitive. And of course it provides a completely latency free monitor mix for your performers.

A Yamaha O1V mixer being used for DAW and live performance monitoring

If you have an alternative solution for combating latency which works for you, please let us know.

Thanks for reading
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Focusrite Liquid channel revisited - the Marmite device

The Liquid Channel has divided opinion like no other piece of gear in recent years and you can read much of it online in forums. Interesting as it is to attempt an evaluation of the device, the issues the discussion has raised are perhaps at least as interesting.

Therefore, here are a few thoughts on the Liquid Channel itself, and the general reviewing process, myths and debates relating to how the Liquid Channel has been regarded and our own fears about acquiring the "wrong" gear.

1. When we read user generated products reviews, such as those used by Amazon, we should often disregard both the 5 star and 1 star reviews, unless either constitute the majority of opinion. How many times have we read a 1 star review to find the reviewer was disgruntled by receiving a product damaged during shipping? Not really a review at all.

2. We should also disregard opinion if it is not clear that the reviewer has actually reviewed the product. Wouldn't it be great to have some method to validate if that was the case? Have you ever wondered how many reviewers with a vested interest have anonymously dammed a "competitors" product in forums?

3. Evaluating a product is no simple thing. Simply setting up an equitable A-B comparison is challenging. Try comparing and evaluating mic-pre's for example. Can you think of a robust process? For example, how can we accommodate the fact that a given mic's sound and performance will alter depending on the impedance of the pre? The effect may be subtle but it cannot be discounted. Also, how are we to record a performance to 2 mic pre's simultaneously? It may require 2 identical mic's positioned in the same physical space. Not easy. Much easier to compare a line level device, such as the Liquid Channels compressor replicas with a line level signal.

4. The Liquid Channel has sophisticated switching circuitry to reproduce what a mic "sees" when it is connected to a range of classic mic-pre devices. If you've ever built a mic pre, pop the lid on the Liquid Channel and take a look at the input stage. It's impressive and comprises a significant proportion of the weight and circuitry of the device. Once the signal has passed through this circuitry it is subject to the convolution process (so called "replicas") which reproduces the non-linear frequency response and distortion characteristics of the mic-pre device from which the impulse responses were taken.

5. Convolution is not emulation. It is not physical modelling or virtual algorithms. What it is is an exact "genetic" fingerprint of the sampled device. Sophisticated maths, requiring lots of processing power, imprints the sonic fingerprint of the impulse response on the signal it is processing. Providing the impulse response is accurate, convolution is capable of reproducing an exact replica of the frequency response and distortion characteristics of the sampled device.

To evaluate the success of this process, the very device from which the impulse response was taken must be compared to the replica. Despite component tolerances improving drastically in the last 20 years (cheap resistors with tolerances of 1% are now commonplace), 2 analogue devices from the same production batch may not sound exactly alike, especially for analogue gear manufactured more than 30 years ago.

6. You can "disable" the replicas and use the Liquid Channel as a high quality transparent mic pre and A to D convertor.

7. All this processing takes time and therefore the Liquid Channel introduces some latency (approximately 3ms) into the signal chain (as do all digital processes). The latency is within the range that occurs naturally in nature as we move around a sound source. For example it takes 2ms for the sound of a drummers snare drum to reach their ears. More here .. http://www.projectstudiohandbook.com/videos/playlists/sound-wave-theory/speed-of-sound/speed-of-sound-video.html

8. We may ask the question, why seek the opinion of others before buying a piece of gear at all? Their are clearly some good reasons (eg does it have manufacturing or ergonomic problems), but a bad reason is because we are frightened of being ridiculed by making a "bad" choice. If our concern is how the gear that we own reflects on how we are perceived by others, then we may want to reflect on exactly what we want to get out of being involved in recording.

It's worth repeating that the "objective" evaluation of a piece of gear is entirely irrelevant to its possible creative applications. History is littered with examples of great sonic innovation coming from humble equipment.

9. For the record, the contributors to this post do not work for Focusrite or have any vested interests whatsoever. They own a Liquid Channel, some 1073's, two Grace Design pre-amps, a Dave Hill Europa, a Triton Audio D20, an ISA430 mk2,  some Yamaha pre's (01V 96), RevA and RevD 1176's, some DBX160s, a Focusrite Red 3, and a Gem Audio Labs Preceptor, and happily use all of them to achieve sounds and sonic effects that please them.

Thanks for reading.
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Beer or gear?

A member of our team recently had a check -up at the doctor. When asked "do you smoke and drink" they replied "not anymore". The doctor asked "when did you stop". "18 years ago" was the answer.

18 years ago was exactly when this team member built their first home recording studio. They were in their early 30's and had been bitten by the recording bug. So absorbed were they by their new interest that they had simply forgotten about socialising, drinking and smoking. They stopped going out and lost contact with many old friends. All the money saved went on buying a new piece of gear.

When the studio had grown sufficiently a few people asked if they could record there, and although the studio was never a full-time commercial facility, each weekend someone came to record or hang-out and a little money was earned which went back into buying more gear.

Soon our team member had a new set of friends, all deeply interested in gear and music. Few of them socialised, smoked or drunk because all their spare cash was spent on their obsessions, recording and making music.

Our team member calculated that around £5000 a year previously spent on travel, booze and fags, and another £2-3,000 from "clients", was now spent on compressors, synths, software and whatever else was on the wish list.

What's your poison?

I guess we all eventually get bored with clubbing, drinking and socialising and this is why many of us are called "boring" by teenagers. But we studio owners are NEVER bored! We cannot remember the last time we couldn't think of something to do. There is always something we want to achieve in our studio, whether it be improving or repairing a piece of gear, or working on the next great song or piece of music. We have a "to-do" list with 46 items on it!

But now with social media we have the best of both worlds. It enables us to maintain contact with all our friends, wherever they are, at almost no cost. We love FaceTime and Skype.

We have never been so connected, had so many conversations, and had so much money to spend on gear. Nothing can entirely replace being in the same physical space as your friends (especially if your mind is on something more than friendship!), but as we sit here writing this post, 3 new messages have arrived from old school friends including an invitation to a Google hangout "reunion". How cool is that!

Thanks for watching and reading
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