3 important questions need to be answered when you are planning to buy a quality speaker for human speech transmission. Answers to these questions are written in the article from SOS electronic. (Reading for 2 minutes)
In the article you will learn:
- what is the basis of good speech reproduction,
- which other features affect the quality of speech reproduction and the long life of the speaker
- which parameter has the greatest influence on the good intelligibility of the reproduced voice
There is no doubt that Visaton is a top manufacturer of speakers from high-end through Hi-Fi to miniature SMD and laptops. They offer solutions for every segment. Martin Brestovič, product manager of SOS electronic, talks about the most interesting group of speakers for industrial equipment, and also about types manufactured especially for the reproduction of human speech.
Today, it is quite common that devices have various messages stored in their memory, and in addition to the optical output on the display or LED and the like, they also give alerts in the form of sound. Typical segments of the use of these loudspeakers are means of transport, kiosks, medical facilities, parking machines, or various systems for voice communication.
What is the essence of good speech reproduction?
First and foremost, the speaker must have good reproduction in the human voice frequency band. We can find many graphs and tables with the average spectrum of voices in the professional literature, and although the individual sources in the data differ slightly from each other, we can state that “everything essential” is between frequencies from 350 – 400 Hz to about 4 kHz. With extra high precision from approx. 200 Hz to 5 – 6 kHz.
This is pretty good news because if you pay just a little attention to the speakers, you probably know that this frequency range can easily be covered by one speaker, and even many small and cheap types can easily cover it.
Which parameter has the greatest impact on the good intelligibility of the reproduced voice?
There is yet another parameter that is very important for the voice to sound really true and have a natural color. It is important that the speaker has the most balanced frequency response (sensitivity) in a given frequency band. This is a slightly higher requirement, and the result of very unbalanced frequency response can be, for example, a typical “metallic” voice coloring and the like.
Equally “rumbling”, not a very understandable sound is typical of speakers (or more precisely reproduction systems from source to a speaker), which emphasize the low tones too much and neglect the higher ones.
The following picture shows two different speakers that should serve as an example of suitable and less suitable frequency responses:
We will now intentionally omit applications where there are large areas and the intelligibility is affected by the echo and also the directional pattern of the speakers. We focus only on “small” applications, where the speaker that is used plays a key role in intelligibility.
What are the other features that also affect the quality of speech reproduction and the longevity of the speaker in the application?
In most cases, a speaker with balanced frequency response is the final solution to achieve quality speech reproduction. But sometimes it can still be beneficial if we use, for example, a speaker with a closed back. This way, we avoid possible sound reproduction rearwards – for example to a closed metal cabinet of the device, where unnecessary disturbing echoes could occur.
Also, depending on the application in which the speaker is placed, it is certainly interesting to know the operating temperature range of the speaker as well as the resistance to water and humid environments. These features also affect the sound quality and the lifetime of the speaker.
If you use a speaker in an industrial device, you will definitely be interested in specific solutions for quality speech transmission. In the second part of this article, SOS electronic will bring you 10 tips for speakers from Visaton‘s portfolio.
More information about Visaton products can be found on SOS electronci website. They will be happy to answer your suggestions and questions at [email protected]
