| 查雪琴.室内低频混响时间特性探讨[J].声学技术,2016,35(5):435~441 |
| 室内低频混响时间特性探讨 |
| Requirements for low frequency reverberation characteristics in rooms |
| 投稿时间：2016-05-03 修订日期：2016-07-20 |
| DOI：10.16300/j.cnki.1000-3630.2016.05.009 |
| 中文关键词: 可懂度 明晰度 掩蔽效应 低频声的干涉 |
| 英文关键词: intelligibility clarity masking effect wave interference |
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| 中文摘要: |
| 室内混响时间要求应从哪个低频段开始，它的混响频率特性又应该是怎样的，它是否可同时适应语言和音乐用途的要求，一直是声学界讨论的问题。有不少规范的低频都是从125 Hz开始；对语言用途的低频段（250 Hz以下）或许可以是平直的，对音乐用途则大都遵循低频上升的“低音比”原则。文章根据不论语言和音乐都在低频有不可忽略的能量，这些能量将会激发小房间内的简正振动（驻波），从而加强了声场中部分低频成分。在大空间内，还因存在低频直达声与反射声到达听者的路程差，使该频段的波长在同量级时出现干涉现象。又因高声级低频对中高频掩蔽效应存在不对称特性等现象，都因干涉作用加强了低频声，掩蔽了对清晰度极为重要的中、高频，最终影响语言的可懂度或音乐的明晣度。因此，为了提高语言可懂度和音乐明晰度，必须在小房间抑制低频驻波，在大空间内减低低频声干涉影响，就必须加大室内低频从63 Hz开始的阻尼，也就是说低频段的混响时间不应提升。在德国的音乐用途大厅（尽管开始时并不是自觉地去执行）由此得到意外的最佳音质效果。笔者在德国十几年间，据此原则从事室内声学设计和研究的经验，在每一个项目中都得到实践证明。 |
| 英文摘要: |
| Reverberation characteristics in rooms are currently under question:What should its spectrum look like? How about low frequencies? Could the same frequency characteristics fit both, music and speech? Acousticians are, since long, at odds about these questions! Most standards limit their requirements only down to 125 Hz, may flat below 250 Hz for speech, but with a bass rise for music. This paper concentrates on the understanding that both speech and music containing considerable energy at the lower frequencies. This may excite the eigenresonances of smaller rooms in the form of standing waves and booming modes. In larger halls the superposition of the direct with the early reflected waves may cause destructive interferences when the wave path difference is of the order of a wave length. The resulting muddy sounds are always causing detrimental masking effect on the mid and high frequency sound which defines intelligibility of speech and clarity of music. Damping these interference effects requires the installation of broadband absorbers efficient down to the 63 Hz octave, thus avoiding a bass rise in reverberation if at all possible. A number of existing as well as newly retrofitted halls and rooms in Germany prove the validity of the author′s innovative acoustical layout concept. |
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