2 x pairs 8ohm speakers wiring to amp - help!

Kn1186

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Hi

I'm hoping that someone could help me with a wiring problem to stereo amplifier (apologies if this is in the wrong forum, I'm a newbie! ).

I have purchased two sets of in ceiling speakers - polk rc80i 100w and yamaha ns-ic600 . Both are 8 ohms speakers.

I have an open plan living room, and was hoping to have one set in the living room, and one set in the dining room. However I was hoping that I could connect both to a single stereo amplifier, which could allow me to play one or the other, but also both sets at the same time.

I was looking into this stereo amplifier from yamaha


Would this amplifier work for this set up? If not, could you help to recommend a better set up or another amplifier please? I am looking to play music through Spotify via a Bluetooth connection.

I will be installing the wires into the wall, and was thinking this would suffice - would these wires be suitable?


Thanks
 
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Hi

I'm hoping that someone could help me with a wiring problem to stereo amplifier (apologies if this is in the wrong forum, I'm a newbie! ).

I have purchased two sets of in ceiling speakers - polk rc80i 100w and yamaha ns-ic600 . Both are 8 ohms speakers.

I have an open plan living room, and was hoping to have one set in the living room, and one set in the dining room. However I was hoping that I could connect both to a single stereo amplifier, which could allow me to play one or the other, but also both sets at the same time.

I was looking into this stereo amplifier from yamaha


Would this amplifier work for this set up? If not, could you help to recommend a better set up or another amplifier please? I am looking to play music through Spotify via a Bluetooth connection.

I will be installing the wires into the wall, and was thinking this would suffice - would these wires be suitable?


Thanks
Most amps with speaker A+B output run the speakers in a parallel connection and so half the speaker impedance. From the caution note below from the manual this amp would seem to be using parallel.
CAUTION
Connect the speakers with an impedance as shown below. If you connect speakers with an excessively low impedance, this unit may overheat.

Speaker connection
SPEAKERS A or SPEAKERS B 8 ohms
SPEAKERS A and SPEAKERS B 16 ohms


So the amp would work OK to switch between either speaker A or speaker B but for A+B would run the speakers at 4 ohms. So there would be a risk of overheating at higher volumes and the thermal protection shutting the amp down.

Also bear in mind that nominal 8 ohm speakers may drop lower at some frequencies to 6 or 4 ohms (perhaps even lower). Again that impedance would be halved during A+B use.
 
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Hi Doug

Thank you for taking the time to reply. Your explanation makes perfect sense.

Am I choosing the right amplifier in this case? I wouldn't say the speakers I've bought are THAT expensive so that's why I thought an amplifier of that price range would be enough. But as you've mentioned, the A+B scenario may cause overheating.

Is there an amplifier then that you could recommend that would be more appropriate for a A+B scenario using the in-ceiling speakers that I've purchased?

Also, could you or anyone help me with choice of speaker wires? I am embedding the wires into the wall, I've read you need the CL2 and CL3 wires for this purpose. What's the difference between them, and which do I need to use in my case?

Thanks
 
Hi Doug

Thank you for taking the time to reply. Your explanation makes perfect sense.

Am I choosing the right amplifier in this case? I wouldn't say the speakers I've bought are THAT expensive so that's why I thought an amplifier of that price range would be enough. But as you've mentioned, the A+B scenario may cause overheating.

Is there an amplifier then that you could recommend that would be more appropriate for a A+B scenario using the in-ceiling speakers that I've purchased?

Also, could you or anyone help me with choice of speaker wires? I am embedding the wires into the wall, I've read you need the CL2 and CL3 wires for this purpose. What's the difference between them, and which do I need to use in my case?

Thanks
Amps
No idea but found this from Denon which specify just 8 ohms for A+B vs the 16 ohms in the Yamaha RS202D.
If the device has an A/B switch for the front speakers and you are able to connect loudspeaker pair A+B and want to operate both pairs together, you should use loudspeakers with an impedance of 8 Ohms or higher. If you use loudspeaker pair A or B, then you can also use 4 Ohm loudspeakers.

Thus I think you'd need an amp which says it can drive 4 ohm speakers so that when you A+B your 8 ohm ones giving 4 ohms it would still be within the amp capabilities. The slightly more expensive Sony STR-DH190 at Richer Sounds specifies 12 ohm speakers for A+B as its minimum recommended is 6 ohm speakers. So still not matching but less mismatch than the Yamaha.

But perhaps worth asking why you want to operate both A+B together?

Cables
CL2 can handle up to 150 volts, CL3 300 volts. I can't see ordinary speakers exceeding 150 volts.
Question - Different speaker cable for front/rears?

What would be more applicable for in wall/ceiling installation would be the fire handling capabilities.
I used this stuff which has a fully certificated LSZH fire rated design
QED QX16/2 LSZH 2 Core Speaker Cable 100m Box - Speaker Cables - AV Online - UK Home Cinema and Hifi Specialists LSZH (Low Smoke Zero Halogen) High performance outer jacket exceeding IEC332-1, IEC60754 and IEC60754-2
You can also buy it by the metre QED QX16/2 LSZH 2 Core Speaker Cable - Speaker Cables - AV Online - UK Home Cinema and Hifi Specialists

News - What is low smoke zero halogen and where should it be used?
Don't know if using this was overkill but where fires may be involved it's perhaps best not to cut corners and skimp on a few pounds. Nothing worse than if you do have a fire and the insurance refuses a claim as 'your cables are to blame'.
 
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Hi Doug

Thanks for your prompt reply again.

That's excellent advice regarding wires, as it's hard to get any UK based audio advice on google these days. Will most likely go for these based on your advice (and the price isn't bad compared to the other brands that I've seen quoted eg Mutec and Monoprice)

Regarding the wires...
*does it matter too much if the wire cable lengths differ? The A speakers will be max 10m whereas the B speakers would be up to 13m?
*would 16 gauge wires you referenced be enough?

Could you send me a link to the Denon amp that you've referenced please?

Thank you
 
Regarding the wires...
*does it matter too much if the wire cable lengths differ? The A speakers will be max 10m whereas the B speakers would be up to 13m?
*would 16 gauge wires you referenced be enough?
The differing lengths will not pose a problem. The longer the length the wider the profile should be. 16 gauge should be enough for 13m and up to 20m, otherwise 14 gauge would be the safer option.
 
Hi Doug

Thanks for your prompt reply again.

That's excellent advice regarding wires, as it's hard to get any UK based audio advice on google these days. Will most likely go for these based on your advice (and the price isn't bad compared to the other brands that I've seen quoted eg Mutec and Monoprice)

Regarding the wires...
*does it matter too much if the wire cable lengths differ? The A speakers will be max 10m whereas the B speakers would be up to 13m?
*would 16 gauge wires you referenced be enough?

Could you send me a link to the Denon amp that you've referenced please?

Thank you
I'd doubt just 3m would make a lot of difference in the signal loss. The conducter resistance is 13.3 Ω/km (QX16/2 and QX16/4 LSZH Speaker Cable) so 0.0133 ohm per metre or just 0.0399 ohm difference in resistance between the two sets. It would cost just 6m * £0.88p or £5.28 extra to have them all equal lengths. You pays your money and you takes your choice...

Some say that wire resistance should never be more than 5% of speaker resistance, so 5% of 8 ohms is 0.4 ohms, 5% of 6 ohms is 0.3 ohms. Whats the max length speaker cable I should consider?

Taking that as gospel (don't know if it is or not) for your 8 ohm speakers using 16 AWG at 0.0133 ohm resistance per metre that is 0.1729 ohm wire resistance for your 13m so OK at both 8 ohms and 4 ohms if running A+B
14 AWG would drop the resistance to 8.27 ohms per km. So 0.107 ohms for 13m or a difference of just 0.0659 ohms between them. Wouldn't seem worth bothering about.

The Denon quote wasn't for a specific product but just a generalised one from their FAQS. But as the cheapest Denon amps with anything like the same power output as the Yamaha or Sony would cost as much (or more) than 2 of them you'd probably end up spending less by just buying one of the cheaper ones for each room....

The Pioneer SXN30AE £329 at Richer Sounds has speaker A+B with 8 ohm speakers Manual notes
You can connect two systems, Speaker A and Speaker B, as the Speaker System. When connecting only one set, connect to the SPEAKERS A terminals. With one set, use speakers with 4 ohm to 16 ohm impedance. Note that when connecting to both SPEAKERS A and B terminals, connect speakers with 8 ohm to 16 ohm impedance to both A and B.

Denon PMA800NE £399 (but just 50W vs 100W for the others). Manual says
Speaker A + B: 8 – 16 Ω/ohms

I'd just suck it and see re possible overheating issues with running A+B together with either the Yamaha or Sony unless you want to spend a lot more money. One risk though is that these amps may run unstable with A+B especially at higher volumes (as you're asking them to operate outside their parameters) and there thus might be a chance blowing the speakers as a result.
 
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Thank you for your help. All your comments make sense and definitely learnt a lot from what you've said. I'll be going with the wires you've recommended and knowing that slightly differing lengths doesn't matter too much is one less thing to stress about. I'll have to do a bit more research on the amp.

Cheers
 
The only thing I would add is that you don't need low smoke / low halon cable in a domestic property. It's only an issue in offices and commercial premises where you could potentially have many miles of it.

The voltages involved will be much much less than you have quoted. A domestic amplifier is highly unlikely to have more than about 25V with respect to earth. A good quality jacketed cable such as Vandamme Blue will provide plenty of protection from damage during installation and is easy to terminate in situ.

You can also get external speaker switch boxes - some with volume controls. This might widen your choice of amplifiers if you are currently looking at only those with 2 speaker outputs. Your other option might be an AV amp with a zone 2 output - which would allow you control of volume and sources in the different rooms, possibly via an app on your phone. Add bluetooth would add to the flexibility of the system allowing direct connection of phones etc. for casual listening.
 
The only thing I would add is that you don't need low smoke / low halon cable in a domestic property. It's only an issue in offices and commercial premises where you could potentially have many miles of it.

The voltages involved will be much much less than you have quoted. A domestic amplifier is highly unlikely to have more than about 25V with respect to earth. A good quality jacketed cable such as Vandamme Blue will provide plenty of protection from damage during installation and is easy to terminate in situ.

You can also get external speaker switch boxes - some with volume controls. This might widen your choice of amplifiers if you are currently looking at only those with 2 speaker outputs. Your other option might be an AV amp with a zone 2 output - which would allow you control of volume and sources in the different rooms, possibly via an app on your phone. Add bluetooth would add to the flexibility of the system allowing direct connection of phones etc. for casual listening.

That's interesting. So I could look into a single speaker output amp (eg. Onkyo A-9110), and use a speaker switch box to hook this up to two sets of speakers?
 
Yes, you can. I use one to switch between the speakers in the summer house and the garden. They're about £15 off Amazon.
 

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