{"product_id":"sabina-the-echo-has-a-clock-physics-t-shirt","title":"Sabina – The Echo Has a Clock Physics T-Shirt","description":"\u003cp\u003eSabina lifts her baton and the echo rings fade on schedule, right when she says they will.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eIn the late 1890s Wallace Sabine, a young Harvard physicist, was asked to fix a lecture room where speech lingered for seconds. Timing how long a sound stayed audible as he brought in seat cushions, he found that reverberation time is proportional to the room's volume divided by its total absorption. The 0.161 comes from 24 ln 10 \/ c with c ≈ 343 m\/s.\u003c\/p\u003e\u003cp\u003eHe went on to advise on Boston's Symphony Hall, which opened in 1900 and is often described as the first concert hall whose acoustics were designed with a quantitative formula. Its occupied reverberation time is about 1.9 s.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eT₆₀ = 0.161 V \/ A,   A = Σ S α\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eT₆₀: time for sound to fall by 60 dB (s)\u003c\/li\u003e\n\u003cli\u003eV: room volume (m³)\u003c\/li\u003e\n\u003cli\u003eA: total absorption (m²)\u003c\/li\u003e\n\u003cli\u003eS: area of each surface (m²)\u003c\/li\u003e\n\u003cli\u003eα: absorption coefficient of that surface\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eWallace Clement Sabine, Harvard, late 1890s; Boston Symphony Hall, 1900.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e Sabine's formula is not exact: it fails for very absorbent rooms, where Eyring's version does better. Sabine's own calculation for Symphony Hall gave 2.31 s, as reported in E. Thompson's history The Soundscape of Modernity (2002); historians attribute the overestimate to how he counted audience absorption.\u003c\/p\u003e\u003ch3\u003eOn the shirt\u003c\/h3\u003e\u003cp\u003eFront: Sabina, the pixel-art character, with “THE ECHO HAS A CLOCK”. Back: Sabine's law, the absorption sum, the 60 dB definition and the Symphony Hall figure. Printed on a unisex tee.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"S \/ White","offer_id":50960520937575,"sku":"75270341677972860987","price":29.99,"currency_code":"USD","in_stock":true},{"title":"S \/ Black","offer_id":50960520970343,"sku":"30420556656348127758","price":29.99,"currency_code":"USD","in_stock":true},{"title":"M \/ White","offer_id":50960521003111,"sku":"14783740889478211875","price":29.99,"currency_code":"USD","in_stock":true},{"title":"M \/ Black","offer_id":50960521035879,"sku":"11581509197452070219","price":29.99,"currency_code":"USD","in_stock":true},{"title":"L \/ White","offer_id":50960521068647,"sku":"30346411397102019158","price":29.99,"currency_code":"USD","in_stock":true},{"title":"L \/ Black","offer_id":50960521101415,"sku":"13965369723055952815","price":29.99,"currency_code":"USD","in_stock":true},{"title":"XL \/ White","offer_id":50960521134183,"sku":"16459640426208742387","price":29.99,"currency_code":"USD","in_stock":true},{"title":"XL \/ Black","offer_id":50960521166951,"sku":"85910444588613522493","price":29.99,"currency_code":"USD","in_stock":true},{"title":"2XL \/ White","offer_id":50960521199719,"sku":"31212001825842121547","price":29.99,"currency_code":"USD","in_stock":true},{"title":"2XL \/ Black","offer_id":50960521232487,"sku":"20937994804072166784","price":29.99,"currency_code":"USD","in_stock":true},{"title":"3XL \/ White","offer_id":50960521265255,"sku":"71826666958680066657","price":29.99,"currency_code":"USD","in_stock":true},{"title":"3XL \/ Black","offer_id":50960521298023,"sku":"17273851100120331823","price":29.99,"currency_code":"USD","in_stock":true},{"title":"4XL \/ White","offer_id":50960521330791,"sku":"30486647476780523091","price":29.99,"currency_code":"USD","in_stock":true},{"title":"4XL \/ Black","offer_id":50960521363559,"sku":"20335870124607116278","price":29.99,"currency_code":"USD","in_stock":true},{"title":"5XL \/ White","offer_id":50960521396327,"sku":"10694050161012745418","price":29.99,"currency_code":"USD","in_stock":true},{"title":"5XL \/ Black","offer_id":50960521429095,"sku":"81391968065120687802","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/sabine-reverberation_front_02_white.png?v=1793625822","url":"https:\/\/pixelatedphysics.com\/it\/products\/sabina-the-echo-has-a-clock-physics-t-shirt","provider":"Pixelated Physics","version":"1.0","type":"link"}