Need advice on wireing speakers for audio

[TCassio]

need some advice on how to wire up some speakers for Whole House Audio (this is a cheap setup, I am evaluating the possibilities). Presently I have 5 8 ohm speakers wired to an ELK 800 10 watt amp. I have 2 sets of 8 ohm speakers wired in series and 1 single 8 ohm speaker all connected in paralelle. Hence an 8 ohm load, I think.

My first concern is this, the Elk docs says:

**NOTE: The ELK-800 is primarily designed for short
duration (intermittent) paging applications. For long durations,
such as playing music, you may need to reduce the
volume output, or lower the power input voltage, or lower
the speaker loading in order to keep the ELK-800 from
overloading and shutting down.

How would I lower the loading so I can play music?

Does this mean a lower ohm value or a higher one?

My second question is this. I just picked up 3 sets of 6 ohm speakers dirt cheap.
How do I wire these in with the 8 ohm speakers so as to meet the requirements of the amp. Here are the amps specs.

Quote:
SPECIFICATIONS:

• Output Rating: 10 Watts.**
• Speaker (Output) Load: 2 to 16 Ohms.**
• Power Input: 12 to 24 Volts AC or DC**
• Current Draw: 50 to 800 mA
• Input Impedance: 1000 Ohms nominal.
• Size: 4.5" x 3" x 1.2".

Features and Specifications subject to change without notice.

Any help is appriciated.
__________________
Thanks,

T.

 

[upstatemike]

Just to understand what you have.... Two sets of 8 ohm speakers in series so each set is 16 ohms. You put the two 16 ohm sets in parallel so you have 8 ohms. Then you put the 5th 8 ohm speaker in parallel with everything which brings you down to 4 ohms. Did I understand that right?

 

[TCassio]

That is correct. So adding the 5th speaker added in paralell brings the load down to 4 Ohms??

 

[WayneW]

Yup, two 8 ohms loads in parallel produces 4 ohms

 

[upstatemike]

The load is not the only issue. With respect to balance, your 5th 8 ohm speaker will be be considerably louder (assuming they are all of equal efficiency) since it is getting 4 times as much power as any of the other ones.

 

[TCassio]

I changed my config, this is what I have. Tell me if I am correct please.

I have 2 8 ohm speakers wired in series = 16 ohms

I have 1 set of 6 ohm speakers wired in series = 12 ohms

I have a second set of 6 ohm speakers wired in series = 12 ohms

I have the three sets hooked up in parallel which yeilds 14 ohms.

is this correct. :huh:

 

[upstatemike]

I get 4.36 ohms. (1/16+1/12+1/12)/1=4.36

 

[upstatemike]

If you go the other way... two 8 ohm in parallel = 4 ohms. Two 6 ohm in parallel = 3 ohms. Then put the three sets in series for 4+3+3=10 ohms. A good load and fairly even power distribution.

 

[TCassio]

Thanks UpstateMike,

Obviously I'm a fish out of water with this so maybe you can help. How would I modify the above configuration to get the load closer to 16 ohms?

 

[TCassio]

I just got your second post thanks, that should do it.

 

[BraveSirRobbin]

Couple of easy equations to help you:

Series resistance is calculated:

R(Total) = R1 + R2 + R3 + R4 + ...

Parallel Resistance is calculated:

1/R(Total) = 1/R1 + 1/R2 + 1/R3 + 1/R4 + ...

Make sure you divide before doing the addition.

Regards,

BSR