dual voice coil plus resistor question

Archived from groups: rec.audio.tech (More info?)

I am planning to power a DIY Shiva subwoofer with an Eosone 910 plate amp.
The Shiva driver has dual voice coils of 8 ohms each and the Eosone has only
a single output targetted for 8ohm driver.

If I will hookup the voice coils in parallel and solder a 4-ohm resistor in
series, would I effectively create an 8 ohm load for the amp? Is there
another way of doing this. Will an 8 ohm amp be damaged by two 8ohm voice
coils in parallel (4ohms)?

Archived from groups: rec.audio.tech (More info?)

On Sat, 12 Jun 2004 12:42:41 -0700, Kevin McMurtrie
<mcmurtri@dslextreme.com> wrote:

>In article <NJDyc.331$h751.295@news04.bloor.is.net.cable.rogers.com>,
> "nntp" <renora@rogers.com> wrote:
>
>> I am planning to power a DIY Shiva subwoofer with an Eosone 910 plate amp.
>> The Shiva driver has dual voice coils of 8 ohms each and the Eosone has only
>> a single output targetted for 8ohm driver.
>>
>> If I will hookup the voice coils in parallel and solder a 4-ohm resistor in
>> series, would I effectively create an 8 ohm load for the amp?
>
>Yes, but it will be 50% efficient.
>
>> Is there
>> another way of doing this. Will an 8 ohm amp be damaged by two 8ohm voice
>> coils in parallel (4ohms)?
>
>Connect only one of the coils. Leave the other one open until you get a
>second amp to drive it or a 4 ohm amp.

Problem is, if both coils are used, the required box is vastly
different than if you use one coil, or a series resistor. Far better
way is to connect the coils in series for now - you get as much
acoustic output as the other options (less drive power but more
efficiency), but the amp sees an easier load (less distortion) and the
box needn't change if you get a second amp to drive the other coil.

A 4 ohm load can damage an amp designed for 8 ohms, but 16 ohms will
always be safe (and actually sound better).

Tony (remove the "_" to reply by email)