Logitech Z-5500, whats impedance?

[kye3k1]

I checked out all the specs before it but what still puzzles me is two things:

- Signal to noise ratio: >93.5 dB, typical 100
- Input impedance: 8,000 ohms

Whats signal to noise ratio
And what is Input Impedance? 8000 ohms seems a hell of a lot compared to all the other speakers I had a look at.

 

[margag_]

Signal-to-noise ratio is closely related to the concept of dynamic range, where dynamic range measures the ratio between noise and the greatest un-distorted signal on a channel. SNR measures the ratio between noise and an arbitrary signal on the channel, not necessarily the most powerful signal possible. Because of this, measuring signal-to-noise ratios requires the selection of a representative or reference signal. In audio engineering, this reference signal is usually a sine wave, sounding a tone, at a recognized and standardized magnitude, such as 1 kHz at +4 dBu (1.228 VRMS).

SNR is usually taken to indicate an average signal-to-noise ratio, as it is possible that (near) instantaneous signal-to-noise ratios will be considerably different. The concept can be understood as normalizing the noise level to 1 (0 dB) and measuring how far the signal 'stands out'. In general, higher signal to noise is better; the signal is 'cleaner'.

So the signal will be x db louder than noise :idea:

 

[margag_]

Generally in audio and hi-fi, the input impedance of components is several times higher than the output impedance connected to them. This is called voltage bridging or impedance bridging. In this case,

Zload >> Zsource

In general, this configuration will be more resistant to noise (particularly power line hum). The best circuits are created by using a voltage follower in the source with the pull-up (load) resistor at the signal receiver.

So a 8000 omh input impedance is how hard the humm will have to work to get in :idea:

 

[kye3k1]

Thanks I think I know what you are on about for the impedence business but I dont know about the whole SNR thing.
I have never taken a look at the audio side of computers in detail before but thanks for your time.

 

[cookingfrags]

basically...the difference from the signal (though it's not that simple, as margag_ noted...let's just say the signal is music) to the noise inherent to the speaker.

for your purposes of buying speakers, noise is the "hissing" you hear when your speakers are turned up loud but have nothing playing over the speakers. the fact that electricity is flowing through the circuits in the speakers guarantees some sort of noise. so if at a given volume the noise is quieter and your music is louder, that is the higher the signal-to-noise ratio, the better and cleaner the sound...makes sense, right?

 

[h1ghf1v3]

so what higher the impedance means what? better bass?

 

[cjl]

High impedance doesn't actually tell you much - the speakers have a separate amplifier, so it's mostly just a meaningless spec.

 

[niko_tr]

High impedance doesn't actually tell you much - the speakers have a separate amplifier, so it's mostly just a meaningless spec.

Actually, it tells you some things. A high impedance input would not load and possibly saturate a voltage source as much as a low impedance input. You would not want your Ipod or whatever to draw tons of current to supply your low imp. amplifier. If the impedance is low enough the source circuit might not be able to supply enough current to reach the intended potential, which would result in a distorted signal. Hope I used the correct terminology.

 

[ssddx]

this thread's last response is from 7 years ago.. closing this.