When recording in rooms with poor acoustic conditions, reflection filters, also known as microphone isolation shields or portable vocal booths, are the best solution for voiceover artists, podcasters, and singers. There are both budget and premium models, but all of them aim to stop the reflected soundwaves from hitting the reflection filter for microphone and causing an unacceptable audio quality.
But, are they worth it? What is the difference between them and a DIY version? Can they be more effective than a DIY version?
We wanted to know the answers so we went out and bought what many consider the ultimate reflection filter – SE Electronics Space. Although it was a large purchase, we felt that the premium model would perform better than expected or offer a greater level of performance than our DIY version. It’s unlikely any other budget models on the market will do as well.
To make sure that the tests are as controlled as possible, we created the following scenarios.
- A dynamic mic is placed in a small space with a low ceiling, lots of surfaces to absorb sound waves (soft furnishings and a carpeted floor) …)
- The same room as the one above, but with a condenser mic
- A dynamic mic is placed in a large space with high ceilings. A lot of reflective surfaces are present, including large windows, a wooden table, and wooden flooring.
- The same room, but with a condenser microphone
In either room, no specialist acoustic treatment or mic placement was used. The shield’s position inside the room was also the same regardless of whether it was placed about the reflection filters. The SPACE was replaced by our DIY version, which was made with items that could be found in the home and not from acoustic foam purchased at a hardware store.
Each one has been recorded as an audio sample so that you can hear the differences.
What is a Reflection filter?
Reflection filters are used to absorb soundwaves that would otherwise reflect onto the microphone. This can lead to reverberation problems. Most reflectors are made of acoustic foam, but some models have multiple layers that include different types and absorbers.
They are popular because of their portability and appeal to people who need more studio space or those who record at home in an area that isn’t acoustically treated.
They are not meant to be used in place of proper acoustic treatment. However, they can be very useful if they are properly placed in the right room with a microphone.
Prices can vary greatly, with prices starting at $40 and rising to $300+. Premium models are built quality, materials, and R&D.
It is important to choose the right materials because they can hurt the intended purpose. They may cause comb filtering which allows a lot of low- and mid-frequency waves to be returned into the microphone.
How reflection filters work
There are two types of reflection filters: an open-top model with an integrated microphone mount, and a box-type design where the microphone sits inside. Both have the same basic purpose: to reduce reverberation and absorb unwanted sound waves, improving audio quality.
Because there is only one side open, the box-type design serves more as an isolation shield. This can result in a less ‘dead sound, which may be good or bad depending on your goals. This is an example of such a design.
The most common open-top design, which is usually a U-shaped shape, sits behind the mic. The microphone’s capsule is typically level with the filter’s left and right sides as shown in this image.
The open design of this room allows for some of the acoustic characteristics of the space to still be present, which can sometimes improve the sound quality. The quality of the final sound will depend on the microphone and reflection filter used, as well as the environment in which it is recorded. How pleasing the recorded sound will be also affected by the properties of the voice that is being used.
Although reflection filters can colorize the sound, it is sometimes a good thing.
What is the purpose of Reflection filters?
Reflection filters are used primarily for voice work. These filters are used by voiceover artists, singers, as well as podcasters. However, they can also be used to record musical instruments.
A reflection filter is most commonly used when the environment in which the recording takes place is not ideal. They are not an ideal solution, however, they do work better at absorbing higher frequencies than the lower ones and only absorb sound waves from behind the microphone.
A cardioid microphone is used for podcasting and performing voice recordings. This means that most of the pickup occurs in front of the microphone, not behind it. Even with a reflection filter sound waves can bounce back to the mic from behind performers. Some sound treatment is highly recommended. However, it is not always possible to improve sound quality. A duvet or acoustic cover can be hung behind the performer who is speaking into the microphone.
Are Reflection filters necessary?
A reflection filter can be very beneficial, especially in rooms that have not been treated with acoustics. A low-sensitivity dynamic microphone can still produce excellent results in large rooms susceptible to echo. To learn more, see our article on the best microphones to use in untreated rooms.
They can still contribute to great sound quality, even with some treatment. They can be used to reduce reflections at the mid-high frequency.
Are Reflection filters effective?
Let’s now get to the fun part: the testing. We chose the SE Elektrons SPACE model because it is a premium, high-end model. Here are the specs:
- Filter system with 10 layers that include the following:
- Vertical bass trap pillar
- Aluminum diffuser with punched holes
- Isolating the air gap
- Acoustic wool absorber
- Recycled paper film
- Tensioned aluminum foil membrane diffusor
- Acoustic wool absorber
- Polycarbonate diffusor
- Asymmetrically isolated air gaps
- Patented polyester acoustic fibreboard
- U shaped design
- 7 Vertical Bass Pillars
- Dimensions (WxHxD: 450x330x250mm
- Vertically and horizontally adjustable and lockable
- Can be tilted at any angle