At the end of May 2016, I had the fortune to record one of my favorite Colombian chamber orchestras, conducted from the beginning by maestro Leonardo Federico Hoyos and on this occasion, with the undeniable collaboration of the Russian violist Irena Sopova, who was visiting the country to perform a series of concerts with various local musicians. The concert repertoire included Tchaikovsky’s Op. 48 string serenade, an elegy for strings by the same composer, Alfred Schnittke’s old-style suite, and Grigoras Dinicu’s thrilling “spring hour”. The assembly of this orchestra is quite simple, a string ensemble made up of 20 talented musicians complemented by the brilliant performance of Irena Sopova as a soloist for some of the pieces.
Image 1. Assemble for Alfred Schnittke’s Polka
The Recording
One of the challenges for this production was the location where the presentation took place, the Mario Laserna auditorium at the University of Los Andes is characterized by being extremely “dry”, despite being a medium-sized stage, the surfaces, carpeting, and reverb, in general, do not provide the characteristic acoustic conditions of the sound of this type of ensemble, which presents a significant challenge in designing a suitable acoustic space in the mixing phase.
Despite the fact that the recording was performed with “mid-range” miking, the experience obtained working with this orchestra in previous years, the knowledge of the sound conditions of the auditorium, and the equipment implemented, provided an advantage when developing a high-quality production. The limitations that may arise in a production (lack of resources, inappropriate locations, equipment) are not an impediment when executing world-class projects, especially in a time where digital tools provide us with software and algorithms that with the passing of the years surprise more with their reach and possibilities.
The audio interface implemented was the Focusrite Saffire Pro 40 which provides us with the 8 preamps needed for this recording, in this case, it has not been necessary to use additional expansions or preamps. Outputs 3-4 have a copy of the main microphone arrangement as backup, recorded on an external device in case of problems with the DAW or the equipment involved in the main recording system.
Image 2. Setup of the interface for recording and its Main backup system.
The microphones
The main stereo arrangement has been made with an AKG p420 match pair in omnidirectional mode, both microphones separated by 1 meter apart on a stereo bar, located approximately 1.90 meters high. The first violin sections and cellos were captured with the Shure PG-81 match pair, a pair of microphones widely used as overheads in drum recordings. In the center, the Behringer C4s were used to support the second violins and violas, however, in the pieces without a soloist, this section was supported with the Marshall MXL 990, a microphone that was used to support the soloist in the Polka and the suite. in Alfred Schnittke’s old-style suite. The double bass section has been reinforced with a large-diaphragm AKG D11 (dynamic) to boost the lower frequencies with the help of exciters in the mixing stage.
Image 3. Microphone configuration for Polka by Alfred Schnittke.
Frequency curves have been generated to counteract some of the shortcomings of these microphones, especially for the C4 and PG-81, which are not the best option for capturing these types of instruments, but with objective treatment, they can serve their purpose of supporting the main stereo arrangement. These “curves” are generated from the spectral analysis of some of the most common microphones in classical music, the article referring to this study’s previous publication. All this is done in order to objectively equalize these microphones taking into account common standards for the genre, thus giving a more accurate sound to the recording and providing the backing arrangements with a high-quality sound. These microphones have also been equalized in the mix phase after applying the corrective curves.
Image 4. Measurement of the frequency response of some of the most used microphones in symphony orchestra recording (Compared to the DPA 4006).
Image 5. Compensation curve for the C4, which response is not very good at the low-end (<250 Hz) and above 2 kHz.
The Mix
The main arrangement has been equalized in different stages, including a Mid-Side equalization phase, implemented especially to control the high frequencies that in the case of these stringed instruments, can become a bit problematic when capturing with the C4s and PG-81s, this equalization process is supported by implementing iZotope’s “Imager”, which allows us to manipulate the stereophonic field in different frequency bands. In addition to this, the arrangement was initially supported with Waves’ RBass to enhance the bass depth in a more dynamic way. This plug-in has also been used in the Shure microphone array, which also features band stereo image control, standard and Mid-Side EQ phases were crucial as well. It is worth mentioning that this arrangement has been boosted around the 5 Kh with the help of T-Racks PEQ 1A, an emulator of the popular Pultec EQP-1A.
Image 6. Some of the most relevant processes of the main microphone array treatment (EQ, Mid-Side EQ, Imager, exciter).
Image 7. Most relevant processes of the treatment of the Shure PG-81 microphones, including the configuration of the PEQ 1A of T-Racks.
Image 8. Treatment setup for the C4 microphones.
All the microphone arrangements mentioned up to this point have been sent to an auxiliary channel with Valhalla’s “Vintage” reverb, a tool that provides reverbs of impressive quality with a “Concert Hall” mode and many controls to modify the space, this tool allows us to design an appropriate space to improve the dry acoustics of this auditorium. Since the natural reverb of the venue does not exceed 1/4 of a second, this plug-in was used to emulate a space with a “Decay” of around 1.17 seconds with a pre-delay of almost 20 ms that seeks to “enlarge” the sound perception in order to give a more accurate spatiality, crucial for this music style in particular. The reverb has also been treated with the “Imager” to extend the low frequencies a bit and contribute to the artificial opening that is sought to give to the stereo image.
Image 8. Treatment setup for the C4 microphones.
All the microphone arrangements mentioned up to this point have been sent to an auxiliary channel with Valhalla’s “Vintage” reverb, a tool that provides reverbs of impressive quality with a “Concert Hall” mode and many controls to modify the space, this tool allows us to design an appropriate space to improve the dry acoustics of this auditorium. Since the natural reverb of the venue does not exceed 1/4 of a second, this plug-in was used to emulate a space with a “Decay” of around 1.17 seconds with a pre-delay of almost 20 ms that seeks to “enlarge” the sound perception in order to give a more accurate spatiality, crucial for this music style in particular. The reverb has also been treated with the “Imager” to extend the low frequencies a bit and contribute to the artificial opening that is sought to give to the stereo image.
Image 9. Reverberation configuration and its treatment in frequency and spatiality.
The bass microphone is enhanced by applying the Rbass to boost the lower frequencies of the double bass section, it also has a strong equalization that seeks to omit some of the upper bands of the spectrum. It should be noted that this mic is not sent to the reverb bus as it could negatively influence the spatial dynamics in the low-end (it is used only as a “backup” for the secondary microphone arrangements). The microphone for the soloist has been treated according to the pieces that were performed in the concert, therefore the equalizations vary according to the repertoire and the disposition of the musicians. In the pieces where Irena Sopova is the protagonist, the MXL 990 has been sent to the reverb bus.
Image 10. Configuration of the equalization and exciters of the microphone of the double bass section.
In the final phase, we have a gain boost stage, supported by plug-ins such as Waves’ CLA-2A and Fabfilter’s Pro-L. In the previous posts, you can find an article referring to this stage and the plug-ins used at the end of the chain of this process. Additionally, Waves’ C6 has been implemented to apply band compression that seeks the control of the deep low frequencies on the musical passages with higher sound pressure levels and high dynamics. The use of “Imagers” with the help of MS Equalization (Waves H-EQ) has been crucial to ultimate details of the stereo image of the overall mix.
Image 11. Some of the processes involved in the final stage. (Gain, Compression, Limiting, Stereo Image, General EQs).
Below you can listen and see the final result of this production. You will also find a link to the STEMS of some fragments so that you can apply what has been analyzed in this publication.
