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[#1] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
例如:

E.g.1

單體:JET III DC氣動高音×1、AS-XR鋁質水晶表面振膜中低音單體×2
頻率響應:30Hz~50kHz
分頻點:450Hz/2.5kHz
建議擴大機功率:30~250瓦
效率:89dB
阻抗:4歐姆
尺寸:1022 × 220 × 320(高×寬×深)


E.g. 2
驅動單體 高音: 1個x 25mm (1 in) 鋁振膜
中音: 1個x 130mm (5 in) FST Kevlar 音盆
低音: 2個x 130mm (5 in) 紙/Kevlar 混合音盆
頻率響應   69Hz - 22kHz ±3dB
頻率範圍 -6dB 於 43Hz 與 50kHz
靈敏度 88dB spl (2.83V, 1m)
推薦擴大機功率 30W - 200W (8歐姆負載不失真)
分頻點 350Hz, 4kHz


最後修改時間: 2011-12-08 00:15:41
cyruschow
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58.xxx.xxx.127
2011-12-08 00:13
[#2] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
我意思係睇個spec 咩數字去計算....

當然, 我明白數字歸數字, 要聽過先知.... 但都想知點計點睇...

Thanks!
cyruschow
個人訊息 會員
58.xxx.xxx.127
2011-12-08 00:18
[#3] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
效率越高越易推。第二是低頻响應。如20Hz to 20KHz +/-3 dB 好推過100Hz to 20KHz +/-3dB
jacky35
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203.xxx.xxx.141
2011-12-08 02:16
[#4] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
靈敏度 & ohm 嘅數值 !!!
avlam
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219.xxx.xxx.229
2011-12-08 02:39
[#5] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
一般倩况

8ohm, 高過 90db 算易推

最後修改時間: 2011-12-08 05:23:03
mild7
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14.xxx.xxx.194
2011-12-08 05:22
[#6] 真心求教:點樣喺數字上知道對喇叭易唔易推??    


最後修改時間: 2011-12-08 09:35:30
faimiu
個人訊息 會員
192.xxx.xxx.193
2011-12-08 09:31
[#7] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
不要信數字遊戲.音箱在播放音樂時阻抗是变化不定時高時低.前後級.cd器材都不可信數字遊戲'.

最後修改時間: 2011-12-08 09:57:46
yipfung
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123.xxx.xxx.75
2011-12-08 09:55
[#8] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
如 : 擴大機功率 30W - 200W (8歐姆負載不失真)

係咪 搵部amp 喺 8ohms 下出到 200w 就最好呢??
cyruschow
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202.xxx.xxx.109
2011-12-08 10:40
[#9] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
總括一下:
(1)靈敏度 (e.g. 高過 90db 算易推)
(2)ohm 數值 (越高越易推, e.g. 8ohm易推過4ohm) )
(3)效率 (越高越易推)
(4)低頻响應 (如20Hz to 20KHz +/-3 dB 好推過100Hz to 20KHz +/-3dB)

Am I correct ???
cyruschow
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202.xxx.xxx.109
2011-12-08 10:45
[#10] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
Actually you have to look into the speaker driver's SPL.

There should be easily driven by a samll amplifier with just a few wattage, if the speaker driver's SPL is more than 94dB.

Speaker driver has less SPL requires much more power (Wattage) to achieve the same maximum SPL of high efficiency driver.

Hope that to clarify your question.
rcywong
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219.xxx.xxx.89
2011-12-08 11:37
[#11] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
Cyrus Hing

you are making good progress!

1) 8 ohm nominal impedence, and 90 db sensitivity is a good reference. 3db drop in sensitivity requires roughly double amplifier power to achieve similar sound level.

2) 4ohm speakers are not necessarily dificult to deal with. They may just require a higher current output from the amplifier. I believe many solid state amplifier today is capable of doing so (with the exception of AV amp). However, try to avoid 2ohm or 16 ohm speakers

3) If the input sensitivity is very high (e.g. > 95db), there is better chance that the speaker may pick up noises/interferences from the signal path.

4) the benchmark for frequency response is 50Hz-20KHz +/-3db. This "3db" refer to the roll off rate at the high freq. and low frequency end. For instance, 100-20KHz, +/-3db is not ideal frequqency response at today's standard. Theoretically, the frequency response range is wider the better, not related with whether it is ease to drive or not

5) A speaker with recommended input 20-200W just give a rough idea of the required amplifier power. It may survive with a 20W amplifier provided it has high quality per wattage. Ideally the output of amplifier is bigger the better, and should not be problem even it is > 200W.
Cheers!!

最後修改時間: 2011-12-08 11:54:51
faimiu
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192.xxx.xxx.193
2011-12-08 11:49
[#12] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
u dont look at nominal impedance as this is an averaged measurement. the swing with different frequencies can be large.

first u look at the minimum impedance. impedance of 4 ohm will draw at least double current than an impedance of 8 ohm. i would say anything below 3.2 ohm may render many amps very difficult to supply ample current. reputable speaker manufacturers will quote minimum impedance figure in specifications.

of course u have to study graphs including phase angle shifts

from wiki:
"Impedance Phase Angle

Impedance variations of the load with frequency translate into variation in the phase relationship between the amplifier's voltage and current outputs. For a resistive load, usually (but not always) the voltage across the amplifier's output devices is maximum when the load current is minimum (and the voltage is minimum across the load) and vice-versa, and as a result the power dissipation in those devices is least. But due to the complex and variable nature of the driver/crossover load and its effect on the phase relationship between the voltage and current, the current will not necessarily be at its minimum when the voltage across the output devices is maximum - this results in increased power dissipation in the amplifier output stage which manifests as heating in the output devices. The phase angle varies most near resonance in moving coil loudspeakers. If this point is not taken into consideration during the amplifier design, the amplifier may overheat causing it to shut down, or cause failure of the output devices. See Power factor for more detail."

also

"Either lower impedance or higher phase angle will require more current from the amplifier. Together both low impedance and greater phase angle will be very difficult for any amplifier to manage. You can have low impedance yet also have a benign phase angle and the demands made on the amplifier will be much less than should a higher overall impedance with a greater phase angle be present. "

cpu8088
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115.xxx.xxx.214
2011-12-09 22:44
[#13] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
Wakaka!

cpu8088識乜叫Phase angle咩?又玩C&P!

喂你唔係話我呃你既咩?E+又學人講phase angel?

睇返呢條thread:

[分享一篇文章-------揚聲器的效率、阻抗與動態]

最後修改時間: 2011-12-09 23:02:08
孟波
個人訊息 會員
123.xxx.xxx.186
2011-12-09 22:56
[#14] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
your statement "除了阻抗曲線,相位曲線(dor line)也是影響喇叭好唔好推的重要因" is totally wrong to me.

why would i have to agree to your baseless statement?

cpu8088

你真係有讀寫障礙,由頭到尾我都係叫你確認唔同意我既論點,幾時要求你同意?

咁你依家即係確認話我講錯啦?正如你阿叔兄話,>>>>又話人地錯又講唔出邊度錯,>>>

之前又話我>>>may be u can trick beginners but u cannot trick me.>>>

我呃你乜呀?呃你去賣屎忽呀?!地。

>>>show me your theory and convince me.>>>

your theory??呢d只係玩hifi既一般常識,又唔係我發明既,點叫得your theory?

成條thread位位師兄都冇話我呃人係得你一個,如果係第二個問我,我一定會同佢詳談,不過睇黎人人都心裡有數,係你cpu8088想抽我水,叫你答條相位曲線代表乜你又唔識答,但又話我講錯,呢d就係火星邏輯?



最後修改時間: 2011-07-07 19:34:14 孟波
會員
218.xxx.xxx.240 2011-07-07 19:14

孟波
個人訊息 會員
123.xxx.xxx.186
2011-12-09 23:21
[#15] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
誰是defeated person?你覺得你贏左?咪笑爆人咀啦。

你龜縮29個小時等我出了12個post後才閃閃縮縮伸個頭出黎嗡兩句,我星期五晚開始擺明約你上黎對質,你有冇應戰呀?

>>>posting some graphs does not mean u know what u are talking about and substantiate your wrong statements>>>

你真係有病,個graph係YS-audio兄post上黎既,雖有兩個但係都係得一款,一條實線(阻抗)一條虛線(相位),有幾複雜。some graphs?得兩個叫some呀?

>>>just post here your explanations at any time u want for all to see.>>>

重有,呢條thread係得你一個唔明個graph,冇人問過呀,我post上黎都係答你一個。

>>>i have already pointed out your wrongs>>>

wrong係邊?pointed out?邊句係?

>>>here i come and go as i like.>>>

即係你唔敢應戰啦?

你未答我:

1.你承認真係唔識條相位曲線代表乜
or
2.你承認目的只係挑釁我,自己唔識唔重要,只係格衰鐘意寸人。
or
3.你其實真係一隻縮頭烏龜。

你如果是旦認一樣,我即刻話你聽點解"除了阻抗曲線,相位曲線也是影響喇叭好唔好推的重要因素。"

今晚又等你。

最後修改時間: 2011-07-10 16:10:00 孟波
會員
218.xxx.xxx.240 2011-07-10 15:53

*************************************************

cpu8088龜縮成5個月先浦頭,唔使冬眠咩?
孟波
個人訊息 會員
123.xxx.xxx.186
2011-12-09 23:35
[#16] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
"相位曲線也是影響喇叭好唔好推的重要因素。"???

a graph is showing measurements plotted in graphic form as a mean of representation. the graph does not itself affect how speakers hard or not hard to drive.

your chinese is so poor. can u post in english?

cpu8088
個人訊息 會員
115.xxx.xxx.214
2011-12-09 23:59
[#17] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
面皮厚唔知醜就係你cpu8088最大優點?

我中文差你睇唔明咩?咁你以後唔好再挑釁我自取其辱啦。

你想我打英文呀,我淨係跟一位英文好叻師兄學過一個dog字,佢當時係用黎稱呼你cpu8088既!

dog係咪狗咁解呀?

最後修改時間: 2011-12-10 00:20:04
孟波
個人訊息 會員
123.xxx.xxx.186
2011-12-10 00:08
[#18] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
ni shi yil tiao wei yang gou,dui bal?
孟波
個人訊息 會員
123.xxx.xxx.186
2011-12-10 12:43
[#19] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
that guy u mentioned misspelled dog. it should be the other way around meaning "god" lol

i have been trying to engage in more technical discussions but u consistently resort to personal attacks. this is infringement of r33 posting rules.

can r33 management do something about this? i have requested this before but no action taken. do u run different rules here for your so called "friends"?

that is why i gather the number of posts have dropped in recent months here. there are better managed forums around the internet.

cpu8088
個人訊息 會員
115.xxx.xxx.214
2011-12-11 07:06
[#20] 真心求教:點樣喺數字上知道對喇叭易唔易推??    
cpu8088, you are confusing people in general here with your cut & paste in the isolate subject such as 'Impedance Phase Angle'.

Apart from what was posted in wiki which you copy and paste, can you derive the equations to justify what you have pasted?

Do you expect any person in the general public be able to measure or even understand the phase relationship between voltage and current when people want to compare or to pick a pair of speakers to buy??

CPU, you are raising an issue which is way beyond by some of the members here (please leave that Impedance Phase Angle issue to the speaker designer to work out), perhaps you should publish a book or create a web-site of yours to allow people to download what you had 'Copy and Paste'.

************
'cyruschow' opening question for this thread in trying to identify based on the speaker spec and be able to pick one pair from another, but how do we expect to know the performance of the speakers based on the specification. I am afraid I have no further answer on top of what was already posted here by other members and I agree, trust your ears, follow the rough guideline to use between 4 ohms to 8 ohms nominal impedance (but impedance varies according to frequencies), the sensitivity issue was also addressed by other members earlier.

I wish speaker designers will be able to give me some clue to why the same speakers in the same room and same position sounded differently even if we change the speaker cable they sound somewhat different.

I always thought of an issue but never been discussed anywhere or by anyone. I believe passive crossover unit can seriously affect the performance of an amplifier especially those amplifiers design with feedback path. I can imagine the back EMF send by the speaker crossover and if somehow gets into the amplifier's feedback path, this may affect the sound quality, and to what extend, this is subject to a timely measurement and to observe the amplifier/speaker behavior and again outside the scope of the discussion here. [Many years ago as a hobbist, I designed and built an amplifier and had experienced such problem] When it come to speaker cable which is the transmission line between the speakers and the amplifier, if the speaker cable somehow can prevent this unwanted or bad EMF being send back to the amplifier, we may be able to accept this as a benefit [indeed finding a suitable speaker cable had made an improvement to my project]. This obviously lead me to think about active crossover application.

I personally felt whatever speakers you are going to use, you have to closely match all the equipment and cable around it. Therefore equipment matching is always important. Yeh Yeh Yeh, everyone knows that but I keep remind myself on this when I am attracted to and wanting to buy a new pair of speakers.

Then again, the hifi dealers and second hand dealers will love our business.

TRUST YOUR EARS to suit your taste when selecting equipment.



最後修改時間: 2011-12-11 10:23:31
NAR
個人訊息 會員
42.xxx.xxx.106
2011-12-11 10:16
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