This post is a lot more personal than most of the previous ones. It is also a long time since my previous post, my apologies, most of 2024 was extraordinarily busy!
Changes – Ends
After a very busy year in 2024, starting with a US tour leg, an Asian tour leg and then an extended run of European Jazz Festivals, it was time for me to review my personal condition, lifestyle and future. This was not a sudden idea, it’s been bubbling under for quite a while. I have been in this industry for many many years, starting as a performer, then a live sound mixer, a classical music recording engineer, a teacher, a Production Company owner and then to commercial contract sound engineering & programming. I retired once, selling out all my corporate ownerships and then immediately got recruited to mix live shows for a well known jazz artist.
It’s inevitable and it’s life, you reach a point where it’s time to quit working so hard, even when you enjoy it immensely. So I quit my FOH mixer position and retired from touring later in 2024.
No more bumpy, endless overnight bus tours, no more 5:00am lobby calls to fly to the next venue, no more very late hotel check-ins when all food & beverage services are closed. It also means that I miss the friendships and support that have built up over years of working together with the other crew members and the artists.
For me, importantly, it means that I really miss amazing musical performances and the energy of live performance.
My life has been a very long and enjoyable career in many aspects of audio and especially live sound mixing.
Changes – Beginnings
As the old saying goes, when one door closes another opens. That has not happened to me yet but I am in the rather privileged situation of being able to consider many different options of what to do next. I don’t really think of retirement as a “never working again” situation. I have a couple of occasional fill-in shows that I do from time to time, those will continue. I have a continuing interest in software, programming and control systems and a couple of projects to work on (more on that later!). I do occasional workshops for theatre and nightclub mixers on getting up to speed and using Smaart to help improve and make their mixes more consistent. We will see how these things keep me occupied and what else will emerge, I’m sure something will.
Newport Jazz Festival - Note two PA arrays "inside PA" under the tent cover and "outside PA" in the scaff towers.
Changes – What audio challenges are still out there
Over the past many years I have been fortunate to learn a lot about how audio systems work, what the industry now does well and what we still do not really have a good handle on. There are many current practices in all areas of audio that bear re-examination and more meaningful interpretation. Here is a short list of things that, in my opinion, need attention.
a) Mixing in stereo or multi-channel audio
These are two different topics but the behaviour of the physical systems introduces the same problems. I’ll discuss stereo but these ideas apply even more to surround or multi-channel audio systems.
I like to mix in stereo and I deal with artists who are mostly acoustic. Mixing acoustic sources in stereo, using stereo or distributed microphones can give acoustic instruments a sense of space, depth and dimension that is unobtainable any other way. This is especially true of larger instruments such as piano, harp, mallets, drums & percussion. Furthermore instrumental sections of strings, woodwinds and brass sound more realistic and sit together better in the mix if they are grouped as stereo mixes instead of mono.
The main problem here is how do you deliver a stereo image to a wide and deep audience area. I like to think about a household stereo system and the idea of setting up an equilateral triangle of two speakers and a listening position then adjusting the toe-in of the speakers to widen the listening field (or sweet spot). It works, and in households and recording studios throughout the world this basic principle is applied. Why then do most PA hangs have the arrays pointing directly out, no toe-in at all?
Well this goes back to the early days of line arrays (and point source arrays) of one speaker or one array covering one part of the audience exclusively and not having any overlap with any other speaker or array. Left array covers the left half of the audience area, right array the right half. Obviously there is no stereo in this kind of configuration because you will never hear a stereo sound field.
The reasons for this have two main points, (i) the interference patterns caused by different arrival times at the listener of a signal from two speaker sources (comb filters). (ii) has to do with the linearity of the speaker response throughout it’s horizontal coverage area.
i. Comb filters are caused by different arrival times (usually from two different speaker arrays) at the listener, at the same level, from a mono source. If you mix with stereo sources, this does not apply. Of course your mono sources are affected (think lead vocal) albeit over a small area where the signal levels are close to the same from both sources. Careful equalisation and good signal processing choices significantly ameliorate this problem.
ii. Most speaker manufacturers publish good information about the performance of their systems including reasonable directivity information. But none perform perfectly and at the location where the arrays are equidistant is where directivity problems usually show up. In the middle of the devices coverage pattern the frequency response is flat and even but on the edges of the coverage pattern is where the frequency response can be quite ragged. Usually it is mid range peaks and valleys, especially in the region where speaker cones transition from piston like activity to multiple areas of radiation. You’ll commonly hear this in the 400-500 Hz region for 15” drivers and 630-800 Hz for 12” drivers. It also happens to horn drivers at the bottom of the coverage control range and in the “waisting” region for the horns. The crossover region(s) can also be a difficult area.
If you pick apart the directivity details for an array you can usually predict where there will be problems and you can definitely hear them. This is particularly true when the array hangs are designed to cover a specific area not covered by any other array e.g straight out. The stitch point between them gets very ugly because this uneven response adds together. Another reason not to mix dead centre of the venue if you can help it!
Interestingly, if you overlap your coverage areas by toe-ing in your arrays you can significantly reduce these overlap buildups simply because more of the audience is in the flat response of the centre of the array pattern and the edge overlaps are isolated to a much smaller area.
I have found over the years that most A1’s and system techs are very resistant to toe-ing in their main arrays, even when a lot of the output is bouncing off the side walls. This attitude comes down to training, usually delivered by the manufacturers themselves.
To me it’s puzzling and unnecessary. Try it yourself, let me know your opinion!
FOH tent setup at Viennes Jazz Festival in France. My desk and rack beside the house desk.
b) Subwoofers – The challenges of horizontal arrays and cardoid stacks
The whole concept of how subwoofers should work, frequency ranges, source configurations, pattern control and coverage areas has been under evaluation and experimentation for many years. In my experience there are very few good answers, lots of compromises and some major trade offs.
But let’s talk about what we actually want from subs first. Ideally I think there should not be any subwoofers. The array should reproduce all frequencies equally along with constant directivity and allow for sufficient power delivery to accommodate our loss of hearing sensitivity at low frequencies (Fletcher-Munson curve). Unfortunately the physics of the devices we use cannot accommodate this kind of performance, at least not with current technology.
Consequently we have subwoofer devices that are optimised to deliver these frequencies with power and accuracy. The other major problem is that at very low frequencies seperated arrays of subwoofers generate major widely spaced interference patterns, the so called “power alley” effect.
Overcoming this problem has led to horizontal arrays of subwoofers lined up along the front of the stage with small spaces between devices and progressively longer delay times applied to the devices as their spacing from centre is increased. This has led to a very even sound field across the coverage area at low frequencies and is now a very common deployment.
However there are significant problems with this solution.
a) Outside the edge of the array the output level plunges, there is literally no sub. If you have any side seating you need seperate sub arrays to cover these areas. Increasing delay times at the outer edge can ameliorate this issue slightly but not significantly, in my opinion.
b) It is impossible to align the phase response at the crossover point with flown stereo or multichannel arrays. There are compromise ways to approximate this but it’s a cluge at best.
c) It is a mono only solution, what happens if you need stereo or multi channel audio response. Many people think this is unnecessary but in musical terms it’s totally necessary. Think about an arpeggiated synth sweep at low frequencies panned across the sound field. Not as uncommon as you might think.
d) It takes a lot more devices than a conventional left/right stack.
Another solution to the “subwoofer problem” is to fly sub arrays beside or behind the main arrays. This has the advantages of maintaining phase alignment with the main arrays and supporting true stereo imaging. It also distributes the power of the systems in a much more even manner throughout the audience area. There is an interesting L’Acoustics technical paper on this topic, I suggest you check it out here
https://aes2.org/publications/elibrary-page/?id=19777
The major disadvantage of this arrangement is creating a power alley. Many shows use both flown left right sub arrays and distributed ground subs basically zoning the coverage areas to get even distribution. Unfortunately this adds to the multiplicity of arrival times and general muddying, especially in the middle of the audience area.
One more interesting solution has been mentioned by Merlijn van Veen and others including a brief commentary by Nathan Lively, link listed below. This is to build left and right subwoofer arrays that are carefully set up to deliver precise cardioid pattern control and to generate even coverage by angling the sub array. The cardioid response pattern helps suppress the power alley effect by nature of the level drop off at increasing distances from the array as a result of the cardioid coverage pattern. If the subs are directly below the main arrays then phase alignment at crossover becomes accurate and predictable across the whole audience area. There are still power alley effects but much lessened by this approach.
There’s a general commentary on gradient arrays and explanation of this solution by Nathan Lively at
https://www.sounddesignlive.com/how-do-you-calculate-cardioid-subwoofer-spacing-gradient-array/
Here is what Jim Yakabuski has to say about the whole topic.
https://www.prosoundweb.com/bringing-the-boom-main-sub-array-configurations-implementation/
Here’s a description of the inimitable Dave Rat’s end fire solutions.
https://www.sounddesignlive.com/dave-rats-end-fire-adjustable-arc-subwoofer-array/
Nearly 40 degC (104 degF) inside the FOH mix tent - Lucca Jazz Festival, Italy. Max that day was 44 degC.
c) Front fill speakers
So what is the job of front fill speakers? Are they a problem area? Well I think they often are. They are their to fill in the main mix to the areas where the main arrays cover least well or where you don’t want major level from the arrays. They also serve to bring the image down to audience level so that the mix at the front doesn’t sound like it’s emanating from the heavens above. Front fills don’t need to be sub heavy, I usually high pass them quite agressively to keep a clean and clear mix . Some people use a modified main mix or just vocals in the front fills, I guess it depends on what is coming off stage and what kind of music it is.
There are two main complications with front fill adjustments that need attention.
a) Timing. Front fills need to be timed back to the arrival time of the main arrays. Where you measure this is quite critical. The important question is how far into the audience do the front fills need to project. This is a judgement call based on how far down the main arrays actually cover and how loud the front fills have to be or can be.
I find that many people expect front fills to cover way more seats than is actually feasible. I typically look to cover 3 or 4 rows of seats max or 15’ – 20’. If you are looking to cover 30’ – 50’ then side stacked infills are a better solution except for the first 3 or 4 rows.
b) Phase Alignment. Even amongst the most carefully engineered ranges of loudspeaker products you will find that some do not exhibit the same polarity or phase response as others. If your polarity is wrong on the front fills then you will have a band of cancellation right across the front of the stage. It’s very obvious when you walk around and listen carefully. Check your analyzer results carefully by checking the mains and the front fills seperately. You can also check the summation of both and try flipping the front fills polarity to see what works best. Be sure to listen to the final result, just to be sure you are OK with what you are hearing.
c) Coverage. I wish that manufacturers made speakers specifically for front fills, especially for theatre use. The scale of arena shows usually allows for more flexibility with speaker choice. Ideally I would look for a 110deg horizontal and 20 deg vertical pattern with a super smooth crossover region. Repurposed point sources rarely have this kind of coverage and although small line array boxes might do they are usually compromised in other ways, especially in frequency response and lack of smoothness because they are designed to be used in arrays. In an ideal world I would like to audition a whole bunch of different boxes just to see what works best.
d) Volume
I wish I did not have to say this but too many shows are way too loud. Is it really necessary for there to be an average SPL of 105 - 110db in the audience area? Basically the answer is no for several important reasons.
i) It damages human hearing in short order. Even moderate exposure times produce permanent damage and the risk of significant hearing damage for staff working in these environments is extremely high.
ii) It doesn’t make the music any better. Some believe that it is more exciting if it’s louder but really that is a critique in itself of the musical content.
ii) Most audio systems struggle to be linear and accurate at high SPL levels, especially if there isn’t enough of a rig to support these levels. Consequently the audio experience is rapidly compromised as the levels go up.
I suggest that everyone involved in live mixing give very careful thought to what levels they really need to mix at and to monitor those levels consistently. Put an SPL app on your phone and use it, is my recommendation.
As a mixer you should be very concerned about protecting your own hearing and adopt good habits at the earliest opportunity. Meter your mixes, carry hearing protection with you at all times, preferably something that is calibrated and can attenuate low frequencies correctly. If you work festivals then use ear plugs all day and night while you are on site, unless you are mixing or sound checking. You will be amazed how much less fatigued you will feel.
Other topics
There are several other topics I would love to explore in more depth but this article has already gone on long enough. Maybe in the future I’ll come back and examine these in more detail.
Manufacturer’s total control of the system configuration
Are the manufacturers of audio systems correct in insisting on specific setup configurations, timing principles, measurement processes and overall control of how a rig is used? One manufacturer is particularly militant, others skew their software to only work in the way they think the system should be configured and others are more hands off. What do you think?
Multi array configurations for dimensional hearing experiences
It’s a great way for a manufacturer to sell a lot more devices but does the audio really sound better in the audience or is it just a way to give musicals more location specific sources?
Are live shows actually about music any more?
Video, and consequently lighting budgets seem to eternally expand whilst the pressure on audio budgets keeps getting more severe. Whilst video is pretty much a necessity in large venues does it compromise the audio quality of the show or relegate audio to a minor role in modern shows? What are live shows actually about and how should a show with major musical content be produced?
Conclusion
Our systems and processes for reproducing live audio have improved by leaps and bounds over the last 25 years and it’s now possible to have great listening experiences more often than ever before. Nevertheless it can still be better and this is what all the comments above are all about. If you have an opinion please let me know.
Last year I did a series of articles about using OSC to control Digico desks. If anyone is interested I may return to this topic and develop a simple monitor mixing app that works for multiple tablets. Let me know if you are interested.
Me with the amazing Japanese audio crew we had on our 2024 Asian tour leg. This was after our last Japanese show in Hiroshima.
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© Clive Alcock - 2025
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