Advice on running 3 speakers from a Wiim Amp

[Rossputin]

Hello all,

I want to drive 3 (outdoor ceiling) speakers – one a stereo pair with its own nearby volume control knob (separate from volume control on the amp) and one a single speaker, also with its own volume control. Since I want the single speaker to contain the audio from both channels, it seems to me that I have two choices:

1. Run the amp in mono and connect two speakers to one channel and one speaker to another channel
2. Run the amp in stereo, connect the pair of speakers the usual way and then connecting both channels to this device to use with the single speaker: CiTR-SM Stereo to Mono Adaptor | KEF USA https://us.kef.com/products/citr-sm-stereo-to-mono-adaptor

My preference is #2 if the Wiim Amp can handle that so that the pair actually runs in stereo. (Would that really be bridging the Amp? Can the Amp do that without a problem?)

What do you think is the best solution, including any idea you have that isn’t either of those?

Thanks,

Ross

 

[Doublej]

Using an in ceiling speaker that is designed to be fed both the left and right channels is another option. Polk Audio RC6s is one example. Whatever you do, you need to be careful about the impedance that the WiiM amplifier sees if you connect multiple pairs of speakers.

Connecting multiple speakers to the WiiM speaker terminals will lower the impedance that the WiiM amp sees. Go below a certain impedance and you'll create problems for the amplifier. One possible way around this are to connect your speakers in series. Do this and the amplifier will see an impedance that is the sum of the impedance of each speaker in the series and should not cause a problem for the amplifier.

 

[Rossputin]

Using an in ceiling speaker that is designed to be fed both the left and right channels is another option. Polk Audio RC6s is one example. Whatever you do, you need to be careful about the impedance that the WiiM amplifier sees if you connect multiple pairs of speakers.

Connecting multiple speakers to the WiiM speaker terminals will lower the impedance that the WiiM amp sees. Go below a certain impedance and you'll create problems for the amplifier. One possible way around this are to connect your speakers in series. Do this and the amplifier will see an impedance that is the sum of the impedance of each speaker in the series and should not cause a problem for the amplifier.

Hey there, I'm aware of those speakers but already have all my speakers. So I guess the question comes down to whether the use of the particular device linked above will cause a drop in impedance as you suggest...or too much of a drop.

 

[Wiimer]

Hey there, I'm aware of those speakers but already have all my speakers. So I guess the question comes down to whether the use of the particular device linked above will cause a drop in impedance as you suggest...or too much of a drop.

Here are the official comments on the four-speaker connection

The WiiM amp is also capable of handling loads up to 2.67 ohm.

A safer option is to connect a mono amplifier to the subwoofer-out of the WiiM Amp and connect one speaker to that amplifier. In this case, switch the main speaker and subwoofer to full-range playback in the WiiM app.

 

[Rossputin]

Here are the official comments on the four-speaker connection

The WiiM amp is also capable of handling loads up to 2.67 ohm.

A safer option is to connect a mono amplifier to the subwoofer-out of the WiiM Amp and connect one speaker to that amplifier. In this case, switch the main speaker and subwoofer to full-range playback in the WiiM app.

so on the one hand that is a really clever solution...and on the other hand it makes me get another amplifier...tough call! But let's play along with that for a minute (because I may actually have a little mono amp lying around). In that case, if the single RCA output from the Wiim Amp for the sub has the audio from both channels then I could connect that directly into a single channel of the RCA input on the mono amp?

Separately, how can I figure out mathematically what the impedance would be if I'm running a pair of speakers the "regular way" and then using that stereo-to-mono adapter connected to both channels to drive one additional speaker? I mean, isn't it possible that that would be fine?

 

[Wiimer]

, if the single RCA output from the Wiim Amp for the sub has the audio from both channels then I could connect that directly into a single channel of the RCA input on the mono amp?

Yes.

Separately, how can I figure out mathematically what the impedance would be if I'm running a pair of speakers the "regular way" and then using that stereo-to-mono adapter connected to both channels to drive one additional speaker? I mean, isn't it possible that that would be fine?

I'm afraid I'm neither an audio specialist nor a maths teacher, so I'm not sure. However, if all three speakers are 8 ohms, I don't think there would likely be any issues connecting them in parallel using method (1).
(Are you planning to play the amp at near maximum volume?)

 

[Doublej]

You'll need to know what the impedance of your stereo speaker are and the impedance of the KEF adapter. From what I could find, KEF claims to mirror the impedance of the speaker it is connected to. If this is accurate, then you take the impedance of your stereo speaker and the impedance of your mono speaker and plug it into:

Speaker Impedance Calculator Series Parallel

What makes things a bit tricky is that manufacturers typically specify nominal (average) impedance across the speaker's frequency range, not minimum or lowest impedance in the speaker's frequency range. But you could create problems for the amplifier if the minimum impedance of speakers connected in parallel is too low.

To calculate the minimum impedance that the amplifier will see, you'll need the impedance (vs. frequency) graph of each speaker.

 

[Rossputin]

I should add the speakers are all 4-ohms...

 

[Rossputin]

You'll need to know what the impedance of your stereo speaker are and the impedance of the KEF adapter. From what I could find, KEF claims to mirror the impedance of the speaker it is connected to. If this is accurate, then you take the impedance of your stereo speaker and the impedance of your mono speaker and plug it into:

Speaker Impedance Calculator Series Parallel

What makes things a bit tricky is that manufacturers typically specify nominal (average) impedance across the speaker's frequency range, not minimum or lowest impedance in the speaker's frequency range. But you could create problems for the amplifier if the minimum impedance of speakers connected in parallel is too low.

To calculate the minimum impedance that the amplifier will see, you'll need the impedance (vs. frequency) graph of each speaker.

ok, but is it 4 ohms in parallel with 4 ohms in my configuration?

 

[Rossputin]

well, if they're all 4 ohm speakers and the single speaker through the adapter also is 4 ohms then I guess the amp would see 2 ohms and that's below the minimum spec for the Wiim Amp, as I understand.

Which makes me think the best answer is what the person said earlier about using the sub out from the Wiim Amp into a separate mono amp for the third speaker...which I can do. Seems kinda nuts, but it's possible.

And to answer a prior question, I will almost never run full volume on this thing. Probably almost never half-volume.

 

[dtc]

From an impedance perspective you can use a impedance matching speaker selector/volume control like those from Niles or even Monoprice. You plug multiple speakers into them and it shows a 4 constant ohm load to the amplifier.

Alternatively, since you already have volume control knobs check to see if they are impedance matching - many of them are. If not, you could replace the volume controls with impedance matching ones, although that will probably be more expensive than the impedance matching box.

If you are using the amp with external RCA connections you could us a simple 2 to 1 RCA cable to produce mono. Some people will talk about theoretical problems with that approach, but it is a time honored method to do this task.

 

[Rossputin]

From an impedance perspective you can use a impedance matching speaker selector/volume control like those from Niles or even Monoprice. You plug multiple speakers into them and it shows a 4 constant ohm load to the amplifier.

Alternatively, since you already have volume control knobs check to see if they are impedance matching - many of them are. If not, you could replace the volume controls with impedance matching ones, although that will probably be more expensive than the impedance matching box.

If you are using the amp with external RCA connections you could us a simple 2 to 1 RCA cable to produce mono. Some people will talk about theoretical problems with that approach, but it is a time honored method to do this task.

I do think I'll end up with impedance-matching volume controls but not sure that would help if the setup is what I described.

 

[Rossputin]

If I give up on running the pair of speakers in stereo and instead set the Wiim Amp to mono, can I just put two speakers on one channel output and one speaker on the other? And if so, which would I put where? (For example put the pair on one channel so they are at the same volume as each other and put the single speaker on the other channel?)

 

[Doublej]

If I give up on running the pair of speakers in stereo and instead set the Wiim Amp to mono, can I just put two speakers on one channel output and one speaker on the other? And if so, which would I put where? (For example put the pair on one channel so they are at the same volume as each other and put the single speaker on the other channel?)

If you have two identical speakers and you put them in series or parallel on one channel of the amplifier they should have the same level of output. Depending on where each speaker is positioned in the ceiling one might sound louder than the other.

 

[harkpabst]

If you have two identical speakers and you put them in series or parallel on one channel of the amplifier they should have the same level of output. Depending on where each speaker is positioned in the ceiling one might sound louder than the other.

Since the existing speakers have been confirmed to be 4 ohm I'd suggest to stick with connecting one pair in series to one output and the remaining one to the other channel.

With the amp set to mono this setup looks the most reasonable to me, as it doesn't require any additional expenses. Just get the wiring right.