Wiring up extra pair of speakers

[Joseph]

My existing pair of 8ohms speakers currently wired to my amp which supports another speaker connection. The figures on the back of the amp prints A or B: 6 - 16ohms / A+B : 12 - 16ohms.

My question is if I want to connect another pair of 6ohms speakers, will that be OK?

thanks in advance.

 

[muljao]

yes

 

[davedotco]

yes

Specifically recomends the use of 12-16 ohm speakers when using two pairs of speakers at the same time, using one pair 8 ohm and one pair 6 ohm speaker will clearly not meet those requirements.

In the real world they may well work fine, but they may not, particularly if worked hard. Not a recomendation that I would be prepared to make.

 

[Al ears]

yes

Specifically recomends the use of 12-16 ohm speakers when using two pairs of speakers at the same time, using one pair 8 ohm and one pair 6 ohm speaker will clearly not meet those requirements.

In the real world they may well work fine, but they may not, particularly if worked hard. Not a recomendation that I would be prepared to make.

I'd agree, there is a difference between connecting another pair and using both at the same time (A+B) , this I wouldn't advise.

 

[muljao]

Does the "+" sign not indicate you can. If not I'll be very slow to recommend again if my misunderstanding gives the wrong advice.

I thought if an amp said a and b, you'd have to suss it out, but a plus b, just add the numbers, no?

 

[Joseph]

yes

Specifically recomends the use of 12-16 ohm speakers when using two pairs of speakers at the same time, using one pair 8 ohm and one pair 6 ohm speaker will clearly not meet those requirements.

In the real world they may well work fine, but they may not, particularly if worked hard. Not a recomendation that I would be prepared to make.

I'd agree, there is a difference between connecting another pair and using both at the same time (A+B) , this I wouldn't advise.

so if I were to use A+B (using both pairs), what speaker impedance would be OK to pair withe the existing 8ohm then?

 

[Al ears]

By my reckoning the manufacturer states that if both speaker pairs are to be used at the same time (A+B) then both pairs of speakers must be within the range 12-16 ohm.

There aren't many modern speakers that do this. Therefore it would be possible to use either/or but not both.

 

[davedotco]

yes

Specifically recomends the use of 12-16 ohm speakers when using two pairs of speakers at the same time, using one pair 8 ohm and one pair 6 ohm speaker will clearly not meet those requirements.

In the real world they may well work fine, but they may not, particularly if worked hard. Not a recomendation that I would be prepared to make.

I'd agree, there is a difference between connecting another pair and using both at the same time (A+B) , this I wouldn't advise.

so if I were to use A+B (using both pairs), what speaker impedance would be OK to pair withe the existing 8ohm then?

When using two pairs of speakers on an amplifier, they are 'wired in parallel'. Look it up if you do not know what that means.

For two impedences R1 and R2 wired in parallel, the total impedance R3 is given by the formular...

1/R1 + 1/R2 = 1/R3. Simple.

Your original speaker is 8 ohm and the mininimum permisable R3 for your amplifier is 6 ohm, so...

1/8 + 1/R2 = 1/6 ie 1/R2 = 1/6 - 1/8, so 4/24 - 3/24 = 1/24,

hence 1/R2 = 1/24, so R2 = 24 ohm.

Since you are unlikely to find a speaker with a 24 ohm impedance, running two sets of speakers at the same time is best avoided.

 

[Joseph]

Thanks guys for your help, all very clear now.

 

[muljao]

I'm going to look into this more, but I don't think this 24 ohm speaker is the case.

-firstly, disclaimer, what I believe and what is correct may be 2 different things, and also what has worked for me in the past may not be correct

I dont believe firstly that an amp manufacturer would put a second set there and only allow speakers that are pretty much unavailable for the most part

I also don't believe Mr. Denon or Mr. Marantz or Mr. Pioneer expects the average user like myself to know the difference between loads in series and loads in parallell. I think the simple a+b on the back, and in instruction manuals is simply that.

I recently had an amp start to cut out because I was using 6 ohm speakers, the manual stated it needed 8-16 ohm speakers (a point I had missed), so the lower ohm speakers allowed more current to flow, increasing heat and the thermal cut. So it seems lower impedance speakers cause the most problem for amps. Many speakers that allow 2 sets of speakers state on a little placard (A or B, 4 to 16 ohms) (A+B 8 to 16 ohms). Now that I write this the second one seems unclear, does it mean combined or each set? I'd imagine its one or the other and the in paralell equation is not expected from us.

As said, I'll try resaerch this a little more and come back, not to be arguementative, just to clear it up

 

[muljao]

Just looking at this link (it makes more sense now) on the manual for a Marantz pm 6006

http://manuals.marantz.com/PM6006/NA/EN/DNTXSYirhopzfc.php

One set speakers limited from 4-16 ohms,

2 sets speakers 8-16 ohms.

The way it is explained here implies to use speakers depending on use. I read that if you use 2 sets of speakers they should BOTH Pairs be rated in the 8-16 ohms range. this makes sense as 2 pairs of 8 ohm speakers in paralell end up at 4 ohms load. I am subject to correction on my interpretation.

To Op, sorry for the "yes" answer in post 2. This, was indeed likely (unintentionally) false information, though I had similar set ups in the past and never had issues, though likely if I had driven them to big volumes I may well have had. I suspect from your original post that if you want to drive 2 sets at once they may both need to be in the 12-16 ohm range for both pairs

 

[Al ears]

Just looking at this link (it makes more sense now) on the manual for a Marantz pm 6006

http://manuals.marantz.com/PM6006/NA/EN/DNTXSYirhopzfc.php

One set speakers limited from 4-16 ohms,

2 sets speakers 8-16 ohms.

The way it is explained here implies to use speakers depending on use. I read that if you use 2 sets of speakers they should BOTH Pairs be rated in the 8-16 ohms range. this makes sense as 2 pairs of 8 ohm speakers in paralell end up at 4 ohms load. I am subject to correction on my interpretation.

To Op, sorry for the "yes" answer in post 2. This, was indeed likely (unintentionally) false information, though I had similar set ups in the past and never had issues, though likely if I had driven them to big volumes I may well have had. I suspect from your original post that if you want to drive 2 sets at once they may both need to be in the 12-16 ohm range for both pairs

This is indeed the case. If you managed to use two pairs at the same time successfully in the past then it is probable they were both 8 ohm, not driving them hard, and you were lucky.

It is possible that manufacturers give a little leeway in these figures but I guess, ultimately, that's what the cut-outs are for.

 

[davedotco]

I'm going to look into this more, but I don't think this 24 ohm speaker is the case.

-firstly, disclaimer, what I believe and what is correct may be 2 different things, and also what has worked for me in the past may not be correct

I dont believe firstly that an amp manufacturer would put a second set there and only allow speakers that are pretty much unavailable for the most part

I also don't believe Mr. Denon or Mr. Marantz or Mr. Pioneer expects the average user like myself to know the difference between loads in series and loads in parallell. I think the simple a+b on the back, and in instruction manuals is simply that.

I recently had an amp start to cut out because I was using 6 ohm speakers, the manual stated it needed 8-16 ohm speakers (a point I had missed), so the lower ohm speakers allowed more current to flow, increasing heat and the thermal cut. So it seems lower impedance speakers cause the most problem for amps. Many speakers that allow 2 sets of speakers state on a little placard (A or B, 4 to 16 ohms) (A+B 8 to 16 ohms). Now that I write this the second one seems unclear, does it mean combined or each set? I'd imagine its one or the other and the in paralell equation is not expected from us.

As said, I'll try resaerch this a little more and come back, not to be arguementative, just to clear it up

Are quite correct. Using the information in your first post a speaker of 24 ohms would be required to be 'safe'. This combined with the existing 8 ohm speaker gives an impedance of 6 ohms which is the minimum permisable by the spec as given.

If you do not understand the difference between series and parallel connection, just follow the instructions on the amp. Ie if you wish to use speaker A plus speaker B they need to be 12-16 ohms each, that is quite clear, so no way would a 8 ohm plus a 6 ohm speaker be acceptable. If you are happy to use just speaker A or speaker B, then 6 ohm speakers will be fine.

The same logic applies to the 'revised' spec that you have given us. In this case using speaker A plus speaker B requires a minimum impedance of 4 ohms, as you say, two 8 ohm speakers in parallel, so a combination of your existing 8 ohm speaker and an additiona; 6 ohm speaker will be...

1/8 +1/6 = 1/R3 ie 3.42 ohms.

So not permisable, even with the 'revised' spec.

In the real world, this is not that bad unless the speakers are 'difficult' and should probably work fine at sensible levels. However should the amplifier fail the manufacturer would be within their rights to void your warrantee due to 'misuse'.

 

[muljao]

Thanks.

I understand parallel and series alright. I just meant that I don't think anyone marketing an amp expects us to be able to do maths to be able to figure what speakers we can use.

Is there even 24 ohm speakers out there? Typical of sales numbers, your device can do this with that, but that is not available 🙂

 

[davedotco]

Thanks.

I understand parallel and series alright. I just meant that I don't think anyone marketing an amp expects us to be able to do maths to be able to figure what speakers we can use.

Is there even 24 ohm speakers out there? Typical of sales numbers, your device can do this with that, but that is not available 🙂

*unknw*

Otherwise, just follow the instructions printed on the amp or in the manual.

Neither tells you that playing an 8 ohm speaker plus a 6 ohm speaker is permisable, it's pretty clear.

Speakers that are 16 ohm are available, though not that common, two pairs of this impedance will work in either case. Using the second, revised spec a second set of 8 ohm speakers to add to the existing 8 ohm pair will be fine and they are commonplace.

 

[muljao]

Ya I mistakenly and wrongly said 6 and an 8 were good to go. I stand corrected

 

[andyjm]

If you want to use both pairs all the time and not have it switchable, then it is fine to wire them in series. Wire like this:

Amp+ to speaker 1+, speaker1- to speaker 2+, speaker2- to Amp-

The overall load will be the sum of the two speaker resistances, which will be fine for the amp. If the amp was maxing out at high volume then it is possible that this configuration will be too quiet for you, but you can always give it a try.

 

[GMae]

I am looking to combine a pair of concept 20s (nominal 6ohm) and concept 40s (nominal 8 ohm) on my marantz PM 8005 (A or B: 4-16ohm; A+B: 8-16ohm)

Based on the 1/R formula...it seems that combined amplifier load when both pairs are driven is around 3,43 ohm...which to me does not seem to far from the 4-16ohm of the A or B option( which I interpret as the allowed amplifier load)...or is the difference between 3,42 ohm and 4 ohm putting my set up at risk?

If this seems OK, my other question is, what else can I expect from a technical point of view by combining the concept 20s and 40s. I suppose the "color"of both speakers will be compatible as they are from the same familiy. However, is there a risk/phenomenon that for instance they might interfere (due to the fact that one speaker reacts faster than the other, or something else...) and leave me with a muddled sound experience?

I am already taking some pre-caution by making sure all speaker cables (Sommer Orbit 240 MKII) are of the same length (25m), to be able to put them around my room.

 

[davedotco]

And welcome to the forum.

The Marantz spec is clear enough, were a problem to arise they could claim misuse and refuse to honour the warantee.

However, in the real world, there is a degree of variation in the impedance of any speaker, so the rated impedence is often described as 'nominal', ie an 'average'. While I would expect the combination to work reasonably enough in practice, you are close to the limit so I would advise against driving the setup too hard and keep an eye on the temperature of the amp, if it starts to get abnormaly hot, give it a break.

The '40s are more sensitive than the '20s, so will be slightly louder with the same input power and there is no practical way of adjusting for this. Otherwise there should be no real problems other than that mentioned above.

However, I am wondering why you want to use both sets of speakers at the same time?

 

[GMae]

Thank you for your message and welcome word...

I very much have the impression that with 2 speakers I can hear the direction where the sound comes from, as opposed to when I have a pair of speakers in front and behind me, I feel in a "bubble" of music. A more complete sound experience for me.

(a similar thing is ...when I listen through my headphone, I like to have the speakers on as well as if it are not only my ears listening but my entire body...for me it makes a difference)

At moments I thought this 2 vs 4 speaker experience might have been due to the way I had set-up the 2 speakers, but then again I had set them up in the way mentioned in the concept 20s manual.

Another reason for my preference for 4 speakers is the fact that I often move around in my listening room, and with 4 speakers it is easier to be in a good spot.

The only negative I have encountered with 4 speakers, is the amount of cable necessary...as I wanted all cables to have the same length...
After I added the second pair of concept 20s...the experience became much more enjoyable...and I was quite happy ...there was just some bass missing
So I started to think about the concept 40s or adding a subwoofer. As I was not sure about how I could connect a subwoofer to the PM8005, I started out with buying 2 pairs of concept 40s...and tried them out...to find out that I prefer the combination of a pair of concept 40s in the rear and a pair of concept 20s in the front.

It is as if the highs are better like this than with just 40s, hence my initial question to understand better what happens when I mix 2 pair of non-identical speakers.

For the deep bass I might eventually still add a subwoofer...

 

[davedotco]

Thank you for your message and welcome word...

I very much have the impression that with 2 speakers I can hear the direction where the sound comes from, as opposed to when I have a pair of speakers in front and behind me, I feel in a "bubble" of music. A more complete sound experience for me.

(a similar thing is ...when I listen through my headphone, I like to have the speakers on as well as if it are not only my ears listening but my entire body...for me it makes a difference)

At moments I thought this 2 vs 4 speaker experience might have been due to the way I had set-up the 2 speakers, but then again I had set them up in the way mentioned in the concept 20s manual.

Another reason for my preference for 4 speakers is the fact that I often move around in my listening room, and with 4 speakers it is easier to be in a good spot.

The only negative I have encountered with 4 speakers, is the amount of cable necessary...as I wanted all cables to have the same length...

After I added the second pair of concept 20s...the experience became much more enjoyable...and I was quite happy ...there was just some bass missing

So I started to think about the concept 40s or adding a subwoofer. As I was not sure about how I could connect a subwoofer to the PM8005, I started out with buying 2 pairs of concept 40s...and tried them out...to find out that I prefer the combination of a pair of concept 40s in the rear and a pair of concept 20s in the front.

It is as if the highs are better like this than with just 40s, hence my initial question to understand better what happens when I mix 2 pair of non-identical speakers.

For the deep bass I might eventually still add a subwoofer...

But if it works for you...*unknw*

If you want to add a subwoofer, you can us the 'Pre-out' connectors on the PM8005. This will have no effect on the impedance matching or any other factors, just choose a sub that has 'Line level' inputs, most, but not all, do.

Otherwise, just keep an eye on the volume levels and the temperature of the amp