wiring 3 set of loudspeakers to 1 amp?

[endia]

hello,
my boss asked me some help about wiring 3 set of loudspeakers to his amp and i'm asking that help from you

he wants to locate one set into the room and two sets to terrace but his marantz has 2 set of output (total 16 ohm). is it possible to connect them like this;
say, one set (8 ohm) to first output and those 2 sets (2x4 ohm) to the other output with a simple multiplier box? or should i build (yes, it's my task now) a special circuit?

any help will be appreciated to me
thanks...

[sreten]

Hi,

You connect one 8 ohm set to speakers 1.

You connect the two sets of 4 ohms in series to speaker 2.

That is 2 lefts in series to left speaker 2, 2 rights in series to right speaker 2.

/sreten.

[AndrewT]

Hi,
most amplifiers that have switchable speaker outputs usually put the two sets in series.
The 16ohms requirement seems to indicate that dad's amp does not fall into this category.

As Sreten pointed out you need to connect the 4ohms speakers in series to make 8ohms.
Then connect the two sets up as if they were 8ohms.

The amp then connects the whole lot either in series or in parallel for each channel. You should try to find out which connection method the amp is using.

If your finished system is three sets in series. 8+4+4 on each channel. It will probably sound awfull. The problem is that the impedance of each speaker is not constant so you effectively have put a variable resistor in series with each speaker and also ruined the damping that each cabinet was possibly designed for.
You can partially avoid the problem by only using A or B but the two 4 ohm in series still have the variable impedance.

Try it but be prepared to fork out for an extra 4 channels of power amp to drive the extra speakers. It will sound a lot better and if you keep the power down won't cost too much.

[sreten]

Originally posted by AndrewT
Hi,
most amplifiers that have switchable speaker outputs usually put the two sets in series.

Hi,

most amplifiers with switchable outputs for both are in parallel.

Usually the back says "load 4 - 16 ohms, 4 ohm minimum".

I've never come across an amplifier that puts both pairs in series.

/sreten.

[dnsey]

Are all three sets of speakers to be run at once, or just one set at a time?

[AndrewT]

Hi,
Re posts3&4.
Sreten you may be right, but if the amp normally accepts 4 to 8ohms as a single load and it then says the double load is also 4 to 8ohms this implies series connection. Otherwise the combined loading would be 2 to 4ohms.

If the amp says the combined loading is 16ohm total, the implication is that the two 8ohms speakers are being connectted in parallel giving an effective load of 4ohm. I think this senario of parallel connection applies in the starter's case.

[Cal Weldon]

Originally posted by sreten
I've never come across an amplifier that puts both pairs in series.

Every Fisher solid state I've owned does that. (five in total) It's the only one I can think of though. Even their partner Sanyo didn't do it.

[endia]

hi all, thanks
i apologize for this too late reply..
i thought that 2 sets will be in parallel on 2nd output.. i'm a bit confused now.. should i connect them like a or b?
btw marantz's manuel says total 16 ohm for both channels.. and amp has a switchable otput, also can drive both outputs.

[bjackson]

A+B are exactly the same.

[simon5]

Here is the series wiring...

You put the 8 ohms pair alone on one channel.

You put your two 4 ohms pairs in series on the other channel.