Having had music make up a big part of my life since my earliest memories, both tinkering with audio and being musical since my early teens, along with always wanting to know how things work, has led me in the pursuit of quality sound and music reproduction for many years.
This article aims to give insight into an example of a performance venue with acoustic challenges and the potential causes, compromises, solutions and concerns that surround this type of situation. The main subjects covered discuss:
- Design properties of a space and the acoustic issues which arise due to the intended style and purpose of performance venues.
- The specific acoustic challenges faced by spaces which haven’t been designed for certain types of music or amplification, most notably low frequency clarity and control.
- Subjective analysis of the acoustics and sound quality of a typical performance and the relation between music genre, sound levels, frequency content and overall clarity when the design and acoustic properties of a space are considered.
- Potential reasons for poor acoustics and audio clarity, along with suggested solutions / remedial works to improve both the quality and flexibility of the acoustic environment.
- The difficulties surrounding the prioritisation and implementation of improved acoustics in venues.
What comes to mind when I think of Edinburgh’s old music venues and issues surrounding the sound quality, is an era of patched denim jackets, pints under 25p and cars without power steering. However I find myself confronted today, with the same kind of acoustic issues my father often experienced during the seventies: bad PA quality and vocals being very hard to hear in a live band setting, cavernous stone walled venues with little to no acoustic (purposeful anyway) treatment, along with either excessive or insufficient sound levels.
I had often assumed it was just because many of Edinburgh’s venues were not purpose built for music performances, or at least not being built during an age of electrical amplification of music. However it turns out this is not the case, as an outing last year to a venue I had not frequented before, illustrated.
The Queens Hall is a former church, converted to a performance hall in 1979, with perhaps the main music styles intended to be played there being; classical, jazz and possibly acoustic blues. This conclusion is drawn from the traditional design of the interior of the hall. The venue retains classic church features, such as the pews and uncarpeted flooring, along with low background noise levels, having been designed for a NR25 noise curve, and in reality coming out at NR19. Ref: (James, 1990)
This type of design can lead to slightly longer reverberation times than if the space is designed for speech or electrically amplified music; this is generally to create a greater sense of ambience and envelopment among other acoustic parameters. The prevalence of this long reverberation can extend into the lower frequencies and is regularly longer than in mid and high frequencies. This, I can only hypothesise is to help enhance, for example, the fullness of the sound of an orchestra, which generally has limited low or very low frequency content and of which the amount of power from the instruments in lower frequencies is limited. The lower sensitivity of human hearing in this range of frequencies may also play a role in this longer reverberation time. Another assumption here is that this long reverberation time at low frequencies was designed into the space purposefully.
While this type of acoustic design is congruent with these more traditional music styles, it is not however helpful for good sound with amplified music, such as pop and rock music. The long reverberation time at low frequencies can: become “boomy”, mask other parts of the music, create issues with timing for the musicians and reduce the perceived overall clarity of the music.
It may seem obvious in some respects that spaces such as stadiums, sports halls and classical music halls are clearly acoustically unsatisfactory when it comes to rock and pop performances, as even by their very name, they are not intended for or designed for use with amplified music. Along with this, even if they are used for these types of concerts, more often than not, they have not been acoustically modified for use for rock and pop concerts. Ref: sect 2.1.1 (Eric R Thompson, 2008)
However it should be considered that what is immediately obvious to the acoustician, sound engineer and musician etc, will not always be obvious to the owner or management of a venue and indeed the average member of the public. It may seem that in some cases that more awareness, better education of and a desire to facilitate a general understanding of acoustics may be the best route forward to help raise the importance and subtleties of the subject at large.
Amplified music can often without much difficulty produce high sound pressure levels at lower frequencies Ref: (Niels Werner). When taking this into account in spaces with long reverberation times at low frequencies, the result can often be low frequency waves essentially bouncing off room boundaries continually. This is because the sound pressure of the reverberant component of the sound, is directly related to the sound pressure of the source component, which often leads to a recipe for sonic disaster when audio is amplified.
Further to this, in very large spaces or even moderate ones, air absorption and the directivity of source components can contribute to the frequency response of a room. High frequencies are affected to a greater extent by both of these factors than low frequencies are, further exacerbating the imbalance in frequency response throughout a typical performance space. Also, another potential reason for this could be that, given that the room boundaries have sufficient mass, so that for the most part the low frequency sound energy is reflected back into the room (see acoustics- mass law), the low frequency sound waves are not able to propagate freely, passing through the structure and behaving as if in a free field environment. This leads to higher likelihood of room modes and constructive interference of the sound waves. This is less likely to be a significant issue with high frequency waves. This is because room surfaces, combined with room geometry and materials contained within the room, tend to present themselves as a more diffuse environment for them, along with common materials being significantly more absorbent at these higher frequencies.
Before delving into the details, it should be borne in mind that my view of the acoustic characteristics of this space is based on a subjective analysis. I have no direct evidence of the objective reverberation time of the hall and furthermore information of reverberation at low frequencies. However, having gathered my own evidence from both visiting the venue to directly experience the acoustics and from others reviews on the matter I have come up with some approximate conclusions of the situation and some potential changes or improvements that could be made to the acoustics of the venue.
When first entering the queens hall, one of the first things that is immediately apparent to the acoustician, is the traditional layout of the hall, being a mash up of mid-20th century classical music hall and 19th century church. There are tight, upright wooden pews that run around the perimeter of the hall in a horseshoe shape fashion, about 6 rows deep. A small amount of fabric cushioning is present on the pews; the only other porous fabric material being evident were the curtains on the stage, some carpeting upstairs and a small number of curtains covering the windows on one side of the hall. The ceiling is relatively high; still it does seem that it has been installed lower than the actual original ceiling, potentially to allow for incorporation of ventilation. However it did seem awful stuffy in the hall, especially for a late autumn evening, although this isn’t uncommon for a traditional Edinburgh venue.
The experience that I had at the Queens Hall, would appear not to be just my ears or a wildly one sided subjective analysis, as my dissatisfaction of the sound was backed up by the consensus of patrons and musicians who I spoke to after the gig. Along with this when we moved upstairs to try and gain a better view and positon for the best sound, we were able to hear the chatter of the crowd around us, which became somewhat disturbing. This included several shouts for the guitarist to turn up by fellow gig goers in the crowd beside us. Towards the end of the gig, I moved back downstairs towards the back and noticed a significant increase in bass as soon as I came in the rear doors. This did not seem to even out until I was clear of the overhang of the balcony. The clarity of the guitar along with the vocals seemed to increase when I was downstairs compared to upstairs. As well as my experience with the acoustics, looking at various reviews online of the performances in the Queens Hall for these types of louder amplified gigs shows other unsatisfied gig goers when referring to sound quality.
All this despite the Queens Hall website describing “We can accommodate everyone from a string quartet or a full symphony orchestra, to a full touring rock band and still maintain the excellent natural acoustics of the Hall.” Perhaps the key point to understand here is that significantly different acoustic conditions are required for orchestral/classical and rock music genres in order to get the optimal sound. The most recent, documented refurbishment was in 1996 where the refurbishment of the pews, lighting and carpeting was undertaken. However, there was as far as could be investigated, no mention of acoustic changes or assessment.
It may not be directly the current owners fault, but somewhere down the line, investment has been lacking in the area of acoustics, most notably when related to the room acoustics and reverberation control at least. This seems strange, given that the main purpose of the venue is for music and sound events, you would think that the importance of getting the acoustics right would be of a high priority. Yet unfortunately this has become unsurprising to me, as many, if not the vast majority of music venues in Edinburgh appear to have good acoustics somewhere far down the list of areas to invest in.
Maybe this was a one off for the Queens Hall in terms of how the music sounded, but nonetheless it shows difficulty in the ability to respond to different acoustic requirements. In light of the large number of good reviews online regarding the acoustics of the venue, it appears that most of these reviews are when acoustic, jazz or orchestral music has been played.
Further investigation revealed that there were several remarks / reviews of unsatisfactory sound, with most of the reviews having been when there was either, a more typically loud act or rock style act performing. Even with the style of performance taken into account there are still unfavourable comments regarding acoustics when mainly speech was the primary source. However it should be mentioned that this could have been due to bad mixing or other shortfalls, so this may not be totally clear cut.
Below are some examples of less favourable reviews of the acoustics.
“We saw Henning Wehn here during The Festival, not particularly comfortable, acoustics not good and unbearably hot.
Not again for us.
Visited August 2015”
“A good venue for a “more intimate” atmosphere – probably better for jazz than more mainstream bands.”
The following review I believe sums up the issues with the acoustics in the Queens Hall rather well, when used for rock music and / or loud amplified music, reinforcing that it was not just my, or my friend’s experience.
“Eric Johnson is without doubt a very accomplished guitarist and having heard a number of studio performances and seen video of his live performances with G3 some years ago – I was very much looking forward to this concert – since EJ tours of the UK are few and far between and particularly as we had bagged decent seats for this date. The concert was unfortunately marred by very poor sound quality – the guitar sound (lets face it – the primary reason to see the guy) was often lost in the mix and was plagued by a constant hum during quieter interludes – which Eric, himself made reference to during the show. Whether it was as a result of this that the bands performance was affected, I dont know, but I felt that the band lacked stage presence and enthusiasm for much of the show and it seemed that for the most part Eric was just going through the motions – with little emotion – and very little interaction with the audience. The high point of the evening was the acoustic set which did not seem to be plagued by the same sound problems and was a much more enjoyable showcase of his and his bands undoubted talents. Im not sure if the sound was down to the venue – this is my first gig at this venue. Overall impression – slightly disappointing…”
The tell-tale sign here is when the performer switched from electric to an acoustic set that the acoustics improved. Often the case with these acoustic sections of a gig is that the rest of the band either does not play or have quieter parts. This illustrates that when the music involves wider ranging frequencies and complex interactions between them, the music hall may be too lively(reverberant) to give good clarity, because as mentioned before, sound masking along with destructive and disruptive reflections cause sonic problems. This could be linked to the long reverberation time at lower frequencies – muddying and masking the sound of vocals and guitar. The lower frequencies are not as likely to be as prominent in an acoustic set.
Single instrument performers and especially those using the natural acoustics of the instrument, are more often acoustically enhanced rather than undermined by more lively acoustics of the performance space. This is why artificial reverberation is often heard on studio recordings of solo acoustic instruments and sometimes the recording of the performer and their instrument is done in a large naturally reverberant space. This goes some way to explaining the phenomenon of the acoustics of the queens hall sometimes working favourably for performers and sometimes not.
With this said, I received feedback from my father, who went to see the blues band King King after we had both attended the UFO gig and remarked that due to the style and volume levels of the music King King play, the acoustics were much more conducive to a clear sound.
So in conclusion the main issues in the case when I visited were:
- “Boomy” unclear bass, that masked the rest of the music, along with the kick drum, not being “tight” i.e the frequency content was not right and the longer reverberation of the space at this frequency was easily noticeable due to the more impulsive nature of the drum compared to other instruments.
- Vocals which did not cut through the mix / lacked clarity and definition.
- The guitar sound was not consistent throughout the majority of the hall and like the vocals, lacked clarity and power to cut through the mix.
- Position chosen to view the performance throughout the hall greatly affected the sound quality and balance between instruments. Effects of increased elevation from the performance or wide angles of view along with boundary effects were detrimental to sound quality.
It should be reinstated that these issues are in part due to the above, but also in conjunction with and perhaps the main issue being that the type/ style of music and sound levels were not appropriate for the type of hall and its acoustics.
Although I have not heard an orchestral or jazz performance in the Queens Hall, I would hazard to guess that the acoustics for these types of performances would be satisfactory due to the feedback from online reviews. Along with this, the correlation between the design of the hall and its closeness to typical design recommendations for these styles is more conducive for good sound in these circumstances.
For this type of performance space and because the type of music styles now performed here varies so much, the ideal scenario would be to use some form of adjustable absorption. This would involve elements of the space which transform between a more absorptive and more reflective surface.
The curved rear of the hall certainly does not help with dispersing the sound, in fact, this actually focuses the sound like a concave mirror. As mentioned, it was noticeable when moving from the rear door into the hall from the lobby space, that there was a significant increase in the perceptible bass frequencies in this curved area, not levelling off subjectively to much of a degree until about one or two rows from the end of the pews. It should be added that this area of the hall’s acoustics is not helped by the fact that the overhang of the balcony above, completely covers this seating area.
The other noticeable effect was the increase in clarity of the vocals and guitar when downstairs towards the rear, compared to upstairs. My thoughts are that the increase in clarity at this particular location has more to do with the audio acoustics than reverberation control, as the local area was densely packed with people, adding to the local absorption. I suspect that more of the direct sound from the speakers was reaching the crowd downstairs than at the upper level, however this will be talked about more in the next section.
To help balance a sense of spaciousness, minimise room modes and long reverberation times at lower frequencies, a combination of adjustable absorption, along with diffusive elements would be a good start for improving the acoustics of the space.
Ideally as well, the balcony face could be treated with a combination of angled diffusion panels and absorptive panels. Or to increase the adaptability of the hall – panels that have one side reflective and diffusive, with the other side being absorptive and being flip-able, to vary the reverberation of the hall, depending on the music style to be played. These could be panels which slot into a rail system and can be lifted out and flipped around for quick and easy adjustment.
The ceiling being mostly flat, apart from some light shallow cornicing, would typically lead to more direct reflections and because of it being a large, flat main portion of the internal sides of the hall, is more likely to lead to reflection of lower frequencies and contribute to standing waves. To help reduce this, hanging diffusers, ideally combined with some hanging absorbers from either the ceiling or the lighting/speaker rig could be used to enhance the acoustics of the hall.
Additionally a mixture of large profiled elements and tuned absorbers at the rear of the hall where the curved wall is at both the upper and lower levels would aid in the reduction of increased bass response at the boundary of the rear wall. Furthermore absorption to the underside of the balcony would be desirable in this case too. The ideal scenario would be a redesign of the hall to accommodate for seating with a better view of the stage and more even distribution of the sound from both the sound reinforcement system and the performance area for quieter / acoustic acts and performances. A stage and balcony layout, where a perpendicular view of the performance area is avoided for most performances, with the flexibility to design a temporary stage closer to the middle of the hall surrounded by the audience for more intimate / classical types of music would be most desirable.
A subjective assessment of background levels within the hall was not suitable, as when we arrived, there were already patrons in and around the hall chatting. Along with this the type of music that we were listening to, was typically loud and did not involve any quiet passages (such as classical or jazz pieces may have) which would have led to a greater exposure to ambient levels within the hall.
It was noted when we were seated upstairs that the speakers that were suspended from the lighting rig were not operating or at least not operating at a volume level to contribute effectively to the audio in the upper level of the hall. This meant that the audio that we were hearing upstairs was reliant on the sound reinforcement system installed downstairs for the gig, projecting enough to cover the 1st floor tier. The system that was operating downstairs appeared to be a short line array which was angled only very slightly upwards, but not nearly angled enough to provide accurate coverage to the upper levels. This meant that the direct sound from the speakers was not reaching the upper level well, but was more effectively reaching the downstairs level. Moreover, the on-axis sound from the speaker was first directed towards a reflective surface (balcony face) before reaching the intended audience upstairs. It would also explain why the mix would be better for the audio engineers downstairs, and the overall sound being better downstairs. This is likely because what they would be hearing was the adjusted/mixed near-mid field of sound from the speakers, which is tuned to have the best sound at the mixing desk. It seemed that more of the indirect sound or reverberant sound was of a greater presence upstairs as there was no on-axis sound from any of the speaker systems.
Another factor which may come into play, especially when it comes to the directivity of the sound from the loudspeaker, is the critical distance at which the direct component and reverberant component of the sound are within a few decibels of each other or are the same level. This may play a greater role when listening upstairs as the directivity of the higher frequencies (related to the polar plot of each loudspeaker with respect to frequency) is generally greater (more like a narrow beam) than at lower frequencies. This leads to greater high frequency content and subsequent clarity when the speakers are pointed or directed towards the listener, i.e. on axis. Because the speakers were not adequately directed towards the listeners on the upper level, this tends to lead to lack of clarity and improper frequency response (i.e. not enough high frequency and too much low frequency) at the listening point. Combine this with long reverberation times at low frequencies and the result is a “muddy” sound, lacking clarity, good timing and frequency balance.
The sound system that was present and thought to be operational when I visited appeared to be a non-permanent feature of the hall, being brought in for gigs like UFO. This could perhaps lead to a degree of understanding as to why the sound in the venue was less than ideal. Setting up a sound reinforcement system for this kind of gig is by no means a small or easy task. Having to balance considerations like: placing the speakers so as to avoid excessive feedback from the microphones on stage, not to cause too much of a visual obstruction to the stage, angle and direct the speakers for good coverage, placement of the main mixing desk/ area to get a representative sound, placement of monitors for the performers along with various other challenges mean that getting a good sound can be difficult.
Solutions to this problem lie in a combination of redesign of the hall’s natural acoustics, along with reposition, distribution, utilisation and potential redesign and replacement of the sound reinforcement system.Nonetheless, it seemed like a slightly awkward set up, with the main speakers being pushed relatively far forward due to the depth of the stage, being what looked like a quarter of the way along the length of the hall. This would mean that anyone behind , in line, or very close to but off axis would get a far less than ideal sound and mix of the band than intended by the mixing engineers.
As for the acoustics of the hall, more absorption could be placed around the speakers at boundary surfaces near to the speakers to allow for the surfaces of the room to have a lesser effect on the frequency response of the speakers.
When thinking about the type of sound reinforcement set up that may be most appropriate for the hall itself, a best case would be for a house sound system to be installed that can fulfil the requirements for all types of performances. The reason I say this is as I presume that the house sound system (that looked to be permanent), was not sufficient to provide the sound level requirements for the UFO gig, as they seemed non-operational and there was large speakers that appeared to be brought in specifically for the gig.
Whilst not a straight forward answer to the sound system subject, mainly because of the considerations surrounding potential relocation/ movement of the stage and other considerations such as, electro-acoustic issues like feedback , directionality and frequency response etc, a improvement may be found in using a line array system.
A possible idea could be to use an extended line array speaker system, suspended from a rig at both sides of the stage, starting at the same height as the current suspended speakers, extending down to just below the bottom of the balcony height. As the speakers reach just below the balcony height, they can be curved downwards so as to be directed appropriately towards the crowd on the bottom floor. Another consideration could be to include a small secondary column line array running right beside the main line array, but angled slightly outwards to give good coverage to the crowd to the left and right of the stage.
Additional consideration which may also help with better management and distribution on the audio, would be; multiple subwoofers if necessary to increase sonic headroom and even out bass frequency response, and smaller distributed loudspeakers hanging from the underside of the balcony to provide better sound to those underneath the balcony. These may also be slightly time delayed to aid synchronisation if necessary.
It should be made clear that the Queens Hall is not the only venue in Edinburgh with less than ideal acoustics. In fact in many cases, depending on the type of music played, it may be among some of the better sounding venues in Edinburgh. It could be hinted at that venues are just not willing to spend money on improving the room acoustics, partition sound insulation performance as well as audio equipment. Not only in Edinburgh, it would seem, but throughout the UK and beyond the idea of investing in good acoustics is way down the priority list of many performance venues. The result of this is, for the average gig goer, very little choice when it comes to seeing your favourite artists perform in a place where the quality and clarity is much better than, or on par with listening to them on a basic home stereo.
In my experience, Bannermans and The Caves have the issue of lots of reflective stone with curved ceilings, the Festival Theatre PA can’t project loudly down to the rear seats, the main speakers in Stramash aren’t on par with the quality of the mixing desk or the venue’s live music focus, the mash house is a standing wave nightmare, and the jam house has many of the same problems as the queens hall etc. So the take away here is that the problems mentioned here are not unique and many venues across the capital suffer sonically.
Bearing in mind that everything contained in this piece of writing is just my opinion, I still think there is a lot more sonically, to be desired from many of Edinburgh’s music venues, especially when it comes to heavily amplified music and the spaces it is played in.
These issues and sound characteristics of this type of performance space seem to be common in many of these older buildings (and to my surprise, even new ones!) And even if it were the case that they were not built in an era of electrical amplification, it can be hard to understand why has there not been some remedial measures taken to improve the reverberation characteristics of the venues to accommodate for the vast majority of performances.
The most obvious answer to this is the general public acceptance of, but more often tolerance of these conditions. This means, if your favourite artist is playing somewhere, even if the sound is poor, you’ll still go because it may be one of only a few very rare opportunities, or the only opportunity to see them perform live in your city. Therefore if the punters keep coming, the venue has no incentive to improve the quality of its product and service. So it really boils down to an expense, that if it can be avoided and can’t be directly seen to be harmful to business, most venues would rather not spend. It is however hard to determine where the bulk of the responsibility for poor sound in venues lies. Is it the venues responsibility? Should promotors and artists push for better acoustics by not working with venues with poor sound and stating this to the owners? Should the public formally complain more often or talk with their feet and return less to venues with bad sound?
Coming back to the Queen’s Hall, I have seen that there is proposed refurb works planned for some time in the next few years or so. This leaves me with some hope that there might be room to include acoustics in the budget, if it is planned on the continued use of the venue for heavily amplified music.
“The Queen’s Hall is about to embark on a major fundraising exercise to refurbish and expand our facilities to celebrate our 40th anniversary in 2019, and to commemorate this historic building’s 200th anniversary in 2023.”
Whether the issues observed at the Queens Hall were more down to the natural acoustics of the space or the position and quality and mix of the audio is hard to say definitively at this stage. This said there were some issues which seemed more akin to one than the other, for example: large increases in bass levels under the canopy and towards the wall indicate issues with the acoustics of the space, whereas changes in the clarity and balance of the sound from the lower level to upper level combined with the fact that there appeared to be no operating speakers at the upper level along with none of the lower speakers aimed to project to the upper level, indicates more of an issue with the audio reproduction acoustics.
Eric R Thompson, N. W.-L. (2008). The importance of bass clarity in pop and rock venues. The Journal of the Acoustical Society of America, 5.
James, A. (1990). Background Noise Levels in Studios and Auditoria. Physique Colloques, 6.
Niels Werner, A.-L. (n.d.). Suitable reverberation times for halls for rock and pop music. Department of Electrical Engineering, Acoustic Technology, Technical University of Denmark, Building 352,.