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kenandterry 12-02-2018 07:06 PM

Stereo speaker questions
I have access to a home stereo system, with an amplifier which comes with two 3 ohm speakers connected by two wires, as it is designed. These speakers contain micro tweeters, tweeters, mid range and bass chamber. The amp boasts 120 watt power output.

I also have two speakers from another dead stereo system which are driven by four wires as they were designed. The speakers contain tweeters, mid range and bass chamber. The four wires are labled to be connected to both 8 ohm (high) and 6 ohm (low).

My impression is that the second set of speakers produced better sound, but Im not sure IF or HOW I could connect them in place of the provided speakers to this new home.

Qualified answers appreciated.

mawilson 12-02-2018 10:07 PM

Odds are the first set has a crossover built into the speaker thus only two wires (signal and ground). The second set has a signal lead for each speaker range and a common ground. You'll need a crossover somewhere before the speakers to separate the signal into the various ranges.

As for the impedance mismatch, ideally you should attempt to match the speakers to the amp. That said, connecting 8 ohm speakers to 3 ohm amp should be okay for most circumstances with two caveats: the 100w spec on the amp will wind up in the 35-40w range at the 8 ohm speakers, you may experience some distortion near max volume.

Connecting 3-4 ohm speakers to an 8 ohm signal without matching impedance via a transformer, L-pad, or creative wiring could damage the speaker as it will be overdriven. At best it will likely be distorted.

kenandterry 12-03-2018 05:53 PM

Thanks Mark.

Id like to discuss in detail further, but we move tomorrow :eek:

Can I talk some more when we get settled later?

kenandterry 12-07-2018 07:51 PM

1 Attachment(s)

Heres a picture of how/where the older speakers were connected to the amp. The red, black, blue, white wires are hard wired into the interior of the speakers.

Now, I only have two connection terminals for each speaker on the amp.

Can I use these older speakers with my newer amp at all? If so, what wires where?


mawilson 12-09-2018 07:51 PM

In general, connecting 3 ohm (are you sure they aren't 4 ohm?) speakers to an amp designed for an 8 ohm load is a Bad Thing(tm). If the amp has a protection circuit, it will shut down. If not, it will probably sound good... for a short while after which the amp will be toast. I mis-spoke about the effect in the earlier post. Matching impedance would be involved and probably not economical.

The options are:[LIST][*]find another amp designed for 4 ohms either with an internal crossover or add an external crossover or[*]find some better 8 ohm speakers with or without an internal passive crossover or[*]use the speakers that came with the amp.

I wish I had better news.

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