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Originally posted by Luis Gabriel GerenaFor instance I was comparing the Swan Diva speaker with an HTD speaker and the Swan gave their specs as Impedance 6ohm while the HTD is impedance 8 ohms. Does that mean I cant directly compared their specs?Regards |

In terms of quality or sound - impedance tells you absolutely NOTHING!

The only use for this spec is in pairing the speakers with an amp - because it tells you

how much of a load the speaker puts on the amp. The lower the impedance, the more

difficult it is to drive, since the amp has to output more current into a lower impedance

load for a given voltage.

For instance - suppose you wanted to "double up" on the Swans - get two of each and put

them in parallel. If you parallel two 6 ohm speakers - you get a 3 ohm impedance - and

that might be difficult for your amp to drive. Amps usually will drive 4 ohms, since there

are many 4 ohm speakers - but lower and you are not guaranteed.

However, if you parallel the 8 ohm HTDs, you would have a 4 ohm load - and you amp

probably could drive that without problem.

Concerns such as those are the reason for the impedance spec. It tells you nothing

about sound quality, efficiency, power handling, how loud they will play...

Best advice is to ignore the impedance spec during speaker selection - and only have

it come into play when you are choosing the amps.

Also, the rating is usually called "nominal" because that is an average of the resistance. Impedance is related to frequency. So, a 8 ohm speaker might have a low impedance of 4 ohms at some frequency, and a high of 12 ohms at another frequncy.

And, you could wire speakers in series. Two 4 ohm speakers in series will give a total of 8 ohms; two 8 ohms=16 ohms, etc., which is easier on the amp.

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Originally posted by Luis Gabriel GerenaIs sentivity also something to consider along impedance. For instance a 6ohm speaker with 90db sentivity will be much harder to move than a 8ohm speaker with a 87db? Is sentivity more important or impedance when easying the load is the matter or are they not related at all?regards |

Here again - sensitivity doesn't tell you about quality - its use will be in selecting an amp.

The lower the sensitivity - the higher the power of the amp needed to drive it to a given

sound level.

Both impedance and sensitivity are used in selecting amps - not speakers.

Impedance will tell you what the load on the amp is.

Sensitivity will tell you how loud the speakers will be with a given amp.

So the 90db one will be 'easier' than the 87db one regardless of ohms. In terms of watts needed.

A higher number in impedance is 'easier' on the amp, some amps will become unstable at low impedance. With lower impedance the output of watts increase from the amp. Thus making the amp work harder.

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Originally posted by Luis Gabriel GerenaFor instance I was comparing the Swan Diva speaker with an HTD speaker and the Swan gave their specs as Impedance 6ohm while the HTD is impedance 8 ohms. Does that mean I cant directly compared their specs? |

Quote:

Originally posted by Luis Gabriel GerenaIs sentivity also something to consider along impedance. For instance a 6ohm speaker with 90db sentivity will be much harder to move than a 8ohm speaker with a 87db? Is sentivity more important or impedance when easying the load is the matter or are they not related at all? |

Obviously, this gets a little complex when we factor both load impedance and sensitivity into the equation at the same time, but be assured that any decent amp will very likely favor the 90dB/6 ohm speaker over the 87dB/8 ohm speaker.

Nominal impedance â€˜use to beâ€™ a rating whose value was limited to not drop much below (1 or 2 ohms lower than stated, I donâ€™t exactly remember) but could exceed (greater than) almost infinitely. It is not an average.

Hereâ€™s a reasonable write up explaining some of the concepts that show even lower sensitivity and lower nominal impedance speakers can be easier to drive.

http://www.symphonysound.com/articles/tubefriendly.html

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