【 Weak current College 】 speaker efficiency impedance (a)---Power By 【 China power house network 】

Twenty years ago, the audio Division, Mr. Lin Yi sheng, referring to the 3/5a, face was like a God, said: it's the efficiency of its low!, but on that day in Panchiao Chen Xiu (sound heard people, immigrants, San Francisco) home, three on the trumpet of the audition, 3/5a play less than five minutes, it was another sound heard people really man a xxx to kaima, shelled down!

Earlier, then only the LP CD, I do not have to increase the record company to buy the album. In the selection of records, that background music strange, how cold the tenor Domingo? nasal so heavy! ask, I discovered that all 「introduction stuffy hoist 」 3/5a get ghost-trumpet is at Rogers import sales upturn.

I am on 3/5a of the ill-feeling is, I didn't think the world famous BBC-3/5a, turned out to be a 「introduction stuffy 」 hoist. Wait until after the trial, I discovered that BBC DaLine did not play the KEF monomer performance extreme, LS-3/5a benefit only small size, low price, no wonder some people will sell 3/5a swap my DaLine transmission line trumpet. The reason is simple, according to 3/5a bass monomer B-110 specifications, can not be installed in such a small speaker! this point it is necessary to note, in fact, the United Kingdom is not BBC design Horn, but easy to carry, had to be speaker design was very small, this is no way to compromise. The original BBC want to designed for one-tenth of the Horn, so the method is simple, and relatively cheap, so he was born LS-3/5a.

Low efficiency Horn did scenery, but after the CD start becoming more popular, people on low-efficiency Horn holding at the end of the name critics, Ying-l-in-charge of the company Mr. Cao Yong, said high dynamic CD will naturally eliminated low efficiency Horn.

Transistor machine w/vacuum machine tile

After 20 years, CD system is maturing, but low-efficiency Horn still exist in the market, and low efficiency = high quality concept seems to have not shaken; until recently in the past few years there has been little change only.

Vacuum tube and go back to the old factory new factory flock, but the machine after the level of the output power is generally lower than Crystal machine. There is the sound quality is supreme, the non-WE300B needless, but also as single-ended not to push. 300B do single-ended only around 7-8W output, can push any loudspeaker 7W? of course, someone with a less than 10W of pipe machine level push ATC loudspeaker-that's a voice, but cannot render dynamic of ATC. The old era of Altec, JBL, EV ... And other large floor-standing loudspeaker are high efficiency, because their parents honey partners is the machine. So when the machine push AltecA7 「introduction theatre voice 」, momentum is significantly different, who can say that mill after the class doesn't do dynamic?

Watt is Watt, tile is Watts, so the pipe machine 7W almost entirely equal to Crystal-7W-difference is the pipe machine output transformer, the output power is less with the load impedance. So if someone says pipe machine 7W than Crystal machine 7W enough force, that is absurd, because the truth is: transistor-7W, most of the time than the vacuum machine 7W enough, never cheat you. There are two exceptions: one is OTL without output transformer pipe machine-level and the other is the famous LS-3/5a trumpet.

Horn's efficiency is expressed using the dB value, but is associated with the impedance. It efficiency, but two pairs of different impedance loudspeaker, it needs a different voltage. Because 8 Ω speakers 1W is input voltage, and 4 2.83V Ω speakers 1W is 2V input voltage. Therefore the same efficiency, impedance of different two pair of speakers connected to the same Crystal after the class will have different representations.

Expand the machine output power ︳ 8 Ω load ︳ 4 Ω load

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1W----------------------2.83V----------2V

2W----------------------4V--------------2.83V

3W----------------------4.9V-----------3.47V

4W-----------------------5.66V---------4V

10W---------------------8.95V---------6.33V

4 Ω speaker needs voltage although than 8 Ω low, but demand current are relatively large, 4W output, for example, 8 Ω speaker is 0.7A, 4 Ω speaker to eat 1A current, so everyone says low impedance driver harder to push.

DB is a DB, its calculation formula will power or voltage and current of the multiples vary speaker efficiency is to power calculation. We now have a great change in impedance of a horn, he said the majority of cases, 7W of Crystal machine than 7W of vacuum machine is strong-key that is current when low resistance.

Speaker impedance │ │ vacuum tube power transistor machine machine power

8Ω--------------------7W------------------7W

4Ω--------------------14W------------------7W

2Ω--------------------28W------------------7W

As long as the driving current enough, Crystal machine output power increases with loudspeaker impedance decreases, so do not just7W. But the machine is turn even the output transformer, power does not change with the loudspeaker impedance. So this is not a Crystal machine 7W rubes of 7W enough force? this is the easiest Omni's law.

3/5a is both a low efficiency, and high-impedance

A constant resistance characteristics of speakers and, therefore, when the speaker impedance Meng to decline, the machine may not force, machine level push after Dynaudio Horn comparison is not easy to make good sound, and therefore intends to take when a speaker, but valve electric current is voltage components to provide current, but swap LS-3/5a won't be the same.

3/5a impedance ｜ Crystal machine power | pipe machine power

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15Ω--------------3.7W---------------7W

11Ω--------------5W-----------------7W

8Ω---------------7W------------------7W

Crystal machine connected 7W first-generation 3/5a is onlyapproximately 3.7W, second generation 3/5a is 5W; but the machine has been maintaining 7W output. They have 3/5a for high-impedance speakers, pipe machine 7W than Crystal machine 7W came enough force. Therefore crystal machine, high-impedance speakers push less good. But why 3/5a high-impedance are 11 ~ 15 Ω? it's KEFT-27A treble monomer and B-110A bass monomers are 8 Ω. This is treacherous, according to the specifications for the design by KEF monomer of the damper and speaker, having surprised, you will find the fundamental LS-3/5a is wrong design!

If high impedance coupled with low efficiency, the trumpet and the convergence with tough, 3/5a have this feature. So someone with a big power to push it, but 3/5a and eat great power, the power is too high, it's easier to hit bottom bass-its KEF dynamic bass monomer nothing. Now let's look at the speaker efficiency and expanding machine power relationships than on trumpet is LS-3/5A and Klipsch's Klipschorn, from the following table we can see low efficiency Horn is harder to wait.

Klipschorn Big Horn │ LS-3/5a trumpet

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104dB/1W----------------------------81dB/1W

107dB/2W---------------------------84dB/2W

110dB/4W---------------------------87dB/4W

113dB/8W---------------------------90dB/8W

116dB/16W--------------------------93dB/16W

119dB/32W--------------------------96dB/32W

122dB/64W--------------------------99dB/64W--？

125dB/128W--？--------------------102dB/128W--？

The first line of 104dB and 81dB is two loudspeaker nominal efficiency, 3/5a's 99dB call?, representing 3/5a cannot withstand 64W continuous input, the bass will hit bottom, 50W continuous input is the maximum value. While the Klipschorn Horn in 1W input, you get the sound pressure of 104dB, LS-3/5a breaking the head is unable to do. As for adding a question mark 125W, that was originally released the Klipschorn maximum 100W continuous work under, so when the continuous input 128W Klipschorn will not. Because of the Klipschorn efficiency up to 104dB, to expand the machine of signal noise ratio (S/N) is not high enough, that do not have to turn the volume knob, Horn emits annoying hiss and hum. For expansion of residual noise machine and hum, high-efficiency Horn's effectiveness with discerning.