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[#81] 裝修完,由柚木地轉磚地,用相同器材低音少左 付出些少時間:耐心:去擺位,些微小事可迎刅而解......! |
KONGKIN55 會員 116.xxx.xxx.40 |
2019-01-12 10:00 | |
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[#80] 裝修完,由柚木地轉磚地,用相同器材低音少左 木地板係最好 |
aheung 會員 219.xxx.xxx.131 |
2019-01-12 08:50 |
[#79] 裝修完,由柚木地轉磚地,用相同器材低音少左 Hi 長長影子, Thanks for your professional advice. I just download an app for my iphone to test the RT60. Attached is the figure shows the result of RT20. By extrapolation, the RT60 would be around 0.36s. Therefore, the corresponding critical distance is 0.56m. The existing distance between my speakers to my listening position is 2m. Therefore, the RT60 is required to be reduced to 0.028s which is much lower than 0.36s. It should be a big reduction. It seems that the cost of required room acoustic treatment may be much higher than my set of lo-fi. :P |
ericelegie 正式會員 222.xxx.xxx.215 |
2011-01-09 09:59 |
[#78] 裝修完,由柚木地轉磚地,用相同器材低音少左 Correct, 咁嘰環境下0.6 m 嘰距離係好短先可以達到... 所以真係要follow IEC規格, 1m距離, RT為0.4s V要成125m2, 不過另一點唔駛咁擔心, 專業用環境RT係要依據硬性規定好多點嘰量測平均值計算出黎, 雖則落差響一個範圍內, 但唔同位置落差較大, 家庭環境擴散性亦比較差, 應用時一般只需要用聆聽點所在位置量測到嘰RT黎計算去計算自己嘰critical distance, 所以實際量測出黎嘰RT會相對(實質全房間嘰等效RT值)比較短 critical distance亦因此亦比較長 (另外實際居住環境太細亦難依規範作多點量測, 另一實際遇到嘰問題係環境背景雜音相對專業環境大, 所以量測數據亦難以量測到-60dB時的殘響數值, 而係需要用-約-5dB 到 -20dB或-30dB嘰slope走勢往下-60dB去求得, 否則RT值嘰量測結果會變得太長), 量測上又可以從Impulse response中搵出時間最接近或最強烈嘰反射impulses, 跟據量測嘰時間去搵出反射位置去應用擴散板或吸音板去推長ITD時間去解決反射太強及Dc太短等問題.. 最後修改時間: 2011-01-07 19:24:55 |
長長影子 正式會員 119.xxx.xxx.148 |
2011-01-07 19:12 |
[#77] 裝修完,由柚木地轉磚地,用相同器材低音少左 Dear 長長影子, Assuming RT60=0.3s and Critical distance, D=0.057*sqrt(V/RT60) [Ref1] Room volume, V = 2.44(W)x5.25(L)x2.73(H)=34.9m3 D is 0.615m. Is it correct? Ref1: http://en.wikipedia.org/wiki/Critical_distance |
ericelegie 正式會員 144.xxx.xxx.139 |
2011-01-07 14:57 |
[#76] 裝修完,由柚木地轉磚地,用相同器材低音少左 acoustics is inherently a very complex subject. if u go to some american forums u will see they consider room treatments, speaker placements and speaker designs very important to achieve good sound. more so than swapping cables or electronics to overcome deficiencies. there are also many professionals tuning your rooms. such as rives: http://www.rivesaudio.com/resources/listening_room/frame.html |
cpu8088 正式會員 115.xxx.xxx.214 |
2011-01-06 19:05 |
[#75] 裝修完,由柚木地轉磚地,用相同器材低音少左 哈哈哈哈! 將佢複雜化, 就顯得自己特別高明! |
k.c 正式會員 119.xxx.xxx.106 |
2011-01-06 12:15 |
[#74] 裝修完,由柚木地轉磚地,用相同器材低音少左 用玻璃做音箱都有,玩音響玩到要分什麼物料的地板,真是攪笑.大把發燒友的家都是用磚地板,好唔好聲就要看個人的功力,你估個個人都會玩得好聲. |
100fun 正式會員 219.xxx.xxx.184 |
2011-01-06 12:00 |
[#73] 裝修完,由柚木地轉磚地,用相同器材低音少左 江湖術士講嘰野冇經過嚴謹驗証, 聽下就好喇咪當係聖經先得架... 大部份環境下Toe-in係必需嘰,因為大多數專業喇叭設計上指向性係被要求, 通常都較能保證正負30度內變化... 喇叭同聆聽點距離最基本限度一定要小於從聆聽環境中嘰RT中去求出critical distance (dc)以內... 最後修改時間: 2011-01-06 02:16:54 |
長長影子 正式會員 119.xxx.xxx.148 |
2011-01-06 02:05 |
[#72] 裝修完,由柚木地轉磚地,用相同器材低音少左 NAR hing: 吾知系咪鄺大俠提過Live recording嗰位。 你指等三角,幾乎被發燒友判左死刑。 1st發燒友吾toe in,吾treat side wall,冇牆角ring尼d概念。 除左,大俠。近乎20年前,重系$3,000focal unit near field,DAT>console>onkyo,等三角近音toe in,大俠猛讚當時播左Unplug1 track1 dat當然過左成2,3年先成CD,原因系dat靚好易,CD靚落好多工夫. 大俠教左我一樣野,故事我講左,点理解看修維 |
TISvili11 正式會員 183.xxx.xxx.206 |
2011-01-05 23:39 |
[#71] 裝修完,由柚木地轉磚地,用相同器材低音少左 Your knowledge in acoustics is appreciated. I suppose u should have ur ECM8000 mic comes with ur EQ, haven't u? Let's try and have funny with it. Not only the simple FFT spectrum but the Cumulative Spectral Decay & Energy Time Freq waterfalls derived from the impulse response. Otherwises, the reflections versus time cannot be distinguished. I totally with u guys that a proper acoustic treatment for a listening environment is very important no matter for omni-source, dipole-source, bi-directional source, etc. I experienced lots of Digital Room Correction solutions for R&D applications, it is a really powerful tool with very high flexibility. At least, the loudspeaker response can be compensated precisely in both time & freq domain under a controlled environment. |
長長影子 正式會員 119.xxx.xxx.148 |
2011-01-05 21:12 |
[#70] 裝修完,由柚木地轉磚地,用相同器材低音少左 你可以send個impulse response過黎,我展開出黎分析貼上黎大家可以一齊討論一下.. thanks remind me the years studying discrete fourier transform ...etc, but i am a analog circuit design guy |
batmanames04 正式會員 180.xxx.xxx.168 |
2011-01-05 09:44 |
[#69] 裝修完,由柚木地轉磚地,用相同器材低音少左 The best way to solve this problem is to change the tile floor back to wooden floor, and this may cost less than changing gears and cables |
muzixman 正式會員 61.xxx.xxx.247 |
2011-01-04 22:15 |
[#68] 裝修完,由柚木地轉磚地,用相同器材低音少左 Must thanks 長長影子 for forwarding the link 'DRC - Digital Room Correction' I find it many audiophile do not believe what is mentioned in paragraph 4.6.3 Speaker placement. This involved the speaker seperation and sitting position. Most engineers sitting in a studio control room are positioned in a equilateral triangle fashion. I had noticed many argument in blogs about how far audiophile should sit away from the speakers. The treated studio room would certainly help minimising all kinds of ill effect caused by an imperfect room such as your living room. I enjoyed reading the article from the link. Thank you very much. |
NAR 正式會員 219.xxx.xxx.99 |
2011-01-04 21:54 |
[#67] 裝修完,由柚木地轉磚地,用相同器材低音少左 你可以send個impulse response過黎,我展開出黎分析貼上黎大家可以一齊討論一下.. |
長長影子 正式會員 119.xxx.xxx.148 |
2011-01-04 21:24 |
[#66] 裝修完,由柚木地轉磚地,用相同器材低音少左 incident wave + reflected wave (t) + [-1 x reflected wave (t) = incident wave], 可以從impulse response量測中比較並睇到反射脈沖被抵消嘰結果, 駐波及RT亦被控制.. 我絶冇話係完美, 但係已經比傳統EQ freq compensation黎得好好多, 使用上更有彈性, 家下好多量聲學測儀器及系統重播都用相同方法做校正處理, 我自己係聲學嘰人我當然都係以聲學處理優先, 但亦會以DSP為附.. It is different, noise cancellation is a feedback control system |
長長影子 正式會員 119.xxx.xxx.148 |
2011-01-04 21:03 |
[#65] 裝修完,由柚木地轉磚地,用相同器材低音少左 Room treatment can be very effective above 200 Hz, but the same result may be obtained more aesthetically with ordinary furnishings, wall decoration, rugs on the floor and the variety of stuff we like to surround ourselves with. How much treatment is needed, or how short the reverberation time should be, depends on the polar radiation characteristics of the loudspeaker. For my open baffle speaker designs a room becomes too dead when its RT60 falls below 500 ms. We can think of sound as propagating like a light ray. Thus, we can use a mirror to find the region on the side wall or ceiling where sound from the speaker might be reflected towards the preferred listening location. It depends on driver, crossover and baffle design, i.e. the polar radiation pattern, whether the region so found is illuminated by sound to any significant degree. If so, then a variety of commercial surface coverings are available to scatter and/or absorb the offending reflection. The acoustically most problematic frequency range is below 200 Hz, because of the spatially and frequency wise irregular distribution of room resonances. Many computer programs have been written that calculate the resonant modes of a given room and recommend optimum loudspeaker and listener placements. Usually, real rooms are much more complex than the calculated models. Walls are not infinitely stiff, rooms have windows, doors, openings, suspended floors or ceilings, etc. In addition, it is the polar pattern and the acoustic source impedance of the given loudspeaker that determines which of the potential room modes are actually excited and to which degree. The usefulness of such programs is marginal at best. Likewise, recommended proportions for room length, width and height should not be taken more seriously than other proportions that may be based on visual aesthetics. The conventional closed or vented box design, that is used for the majority of loudspeakers on the market, contributes significantly to the room problems below 200 Hz. These designs are omni-directional radiators and they tend to excite a maximum number of room resonances, particularly when located in room corners. While this adds to the perceived bass output at certain frequencies, it can lead to a falsification of the recorded material, namely when the room resonance decays more slowly than the original sound. In general, the low frequency response of omni-directional speakers in small rooms is quite non-uniform. Attempts to treat the room with absorbers will make only marginal differences unless very many absorbers or large absorbing surfaces are used. It is best to attenuate peaks in the bass response with parametric equalization. Holes in the response cannot be filled in (Ref. 1). By far the perceptually most uniform response in the range below 200 Hz is obtained with an open-baffle, dipole or figure-of-eight radiating source. Because of its directionality, the dipole excites far fewer room resonances than an omni-directional source. The measured room response is not necessarily any smoother than that for an omni-directional source. But the perceived difference in bass reproduction is startling at first, because we are so used to hearing the irregular and booming bass of the typical box speaker in acoustically small rooms. Quickly one learns to recognize the distortion of this combination and it becomes intolerable. quoted from linwitz lab http://www.linkwitzlab.com/rooms.htm |
batmanames04 正式會員 61.xxx.xxx.217 |
2011-01-04 21:01 |
[#64] 裝修完,由柚木地轉磚地,用相同器材低音少左 非也,正係用DSP控制喇叭黎抵消反射聲嘰影響同時亦能控制殘響, 其他比較特別嘰用途仲有crosstalk cancellation等等.. quoted even thoug like the words you mentioned, your ears still hear sound coming from the incident and reflected waves lets say a single tone asin(wt)expj(theta1) generated from the source, after a single reflection from the wall becomes bsin(wt)ejtheta2 sum of it incident wave asin(wt)expj(theta1) + reflected wave bsin(wt)ejtheta2 never equal to asin(wt)expj(theta1) I am thinking is it possible to get specific signal dwin(wt)expj(theta3) dsp control the driver cone + gsin(wt)ejtheta5 reflected wave = asin(wt)expj(theta1)? |
batmanames04 正式會員 61.xxx.xxx.217 |
2011-01-04 20:35 |
[#62] 裝修完,由柚木地轉磚地,用相同器材低音少左 最後修改時間: 2011-01-04 20:19:31 |
Kenny 正式會員 116.xxx.xxx.145 |
2011-01-04 20:19 |
[#63] 裝修完,由柚木地轉磚地,用相同器材低音少左 Noise cancellation/room correction sounds perfect in theory, but it is better you listen it 1st, before going forward as your mileage may vary. Once you put a processing unit in the chain, there would be a delay (or latency) to the sound reproduction. It can be quite annoying. I am not sure how "jitter" sounds, but it should be close to it. It just does not sound like it is a live recording. PS: NAR: I do see your points. What I merely mention is it is quite tiresome to move big speakers around. |
Kenny 正式會員 116.xxx.xxx.145 |
2011-01-04 20:19 |