Question on OHM and Speaker

[user1]

I just got one of those Aura bass shakers that are 4 Ohms that I am
hooking up for my pathetic home theater. My question (probably a
stupid one) is, my receiver is rated for 8 Ohms. What are the
consequences of running my receiver to the bass shakers? I know
nothing about Ohms. I take it that the lower the Ohm rating, the more
power (and heat).

Any help would be appreciated.

[Mark D. Zacharias]

It could cause problems, from a blown amp channel to a bad power
transformer. You didn't say what brand and model the receiver is.

A lower impedance means the amp is working harder to produce a given voltage
(volume) across a load.

Mark Z.


"user1" > wrote in message
...
> I just got one of those Aura bass shakers that are 4 Ohms that I am
> hooking up for my pathetic home theater. My question (probably a
> stupid one) is, my receiver is rated for 8 Ohms. What are the
> consequences of running my receiver to the bass shakers? I know
> nothing about Ohms. I take it that the lower the Ohm rating, the more
> power (and heat).
>
> Any help would be appreciated.
>

[user1]

Sorry about that. I've got a Sony STR-DE925. It can be switched to 4
Ohms, but the Bose AM-5? (or should I say blows) that I have is rated
for 8 Ohms.or 4 Ohms for only the right and left channel.



On Thu, 14 Aug 2003 10:39:12 GMT, "Mark D. Zacharias"
> wrote:

>It could cause problems, from a blown amp channel to a bad power
>transformer. You didn't say what brand and model the receiver is.
>
>A lower impedance means the amp is working harder to produce a given voltage
>(volume) across a load.
>
>Mark Z.
>
>
>"user1" > wrote in message
...
>> I just got one of those Aura bass shakers that are 4 Ohms that I am
>> hooking up for my pathetic home theater. My question (probably a
>> stupid one) is, my receiver is rated for 8 Ohms. What are the
>> consequences of running my receiver to the bass shakers? I know
>> nothing about Ohms. I take it that the lower the Ohm rating, the more
>> power (and heat).
>>
>> Any help would be appreciated.
>>
>

[Todd H.]

user1 > writes:
> Sorry about that. I've got a Sony STR-DE925. It can be switched to
> 4 Ohms, but the Bose AM-5? (or should I say blows) that I have is
> rated for 8 Ohms.or 4 Ohms for only the right and left channel.

How are you planning on hooking this up? Where are you planning to
plug this bass shaker in and are there any other speakers already
being driven by that channel?

I ask because somehow you'd have to have your Bose AM-5's and this
bass shaker being fed.

First, if the bass shaker is 4ohms, and only your left or right
channel can possibly drive that low of an impedance, you then only
have two choices as to where to place it.

BUT, don't you also have to hook up your Bose AM5's?

If you already have a 4ohm bass shaker load hanging off any channel of
your Sony, and your amp specs say that 4ohms is the minimum impedance
it can safely drive, adding any other speaker on that same channel
will bring it below that minimum, and you risk damaging your amp
(worst case), reducing its life (due to added thermal stress), or
sending it into thermal shutdown in very short order (assuming a well
design overload protection circuit).

I'm afraid I can't see how you can safely use this device with your
receiver. You will need an external power amp, or a powered shaker.

--
/"\ ASCII Ribbon Campaign | Todd H
\ / | http://www.toddh.net/
X Promoting good netiquette | http://triplethreatband.com/
/ \ http://www.toddh.net/netiquette/ | "4 lines suffice."

[user1]

According to the wiring instructions on teh Aura site, it says to take
the subwoofer output to an amp, and from the amp to the bass shaker.
The Sony has 2 sets of speaker outputs. I have the Bose going through
the 1st set of outputs. From what it sounds like (and from what I was
thinking) it would be a bad idea for me to run the bass shaker off the
2nd set of speaker outputs.

I guess I'll have to get a cheap amp to run it off the subwoofer
output.

Thanks for all your input... it saves me from burning out the receiver
and having to get a new one.


On 14 Aug 2003 07:19:33 -0500, (Todd H.) wrote:

>user1 > writes:
>> Sorry about that. I've got a Sony STR-DE925. It can be switched to
>> 4 Ohms, but the Bose AM-5? (or should I say blows) that I have is
>> rated for 8 Ohms.or 4 Ohms for only the right and left channel.
>
>How are you planning on hooking this up? Where are you planning to
>plug this bass shaker in and are there any other speakers already
>being driven by that channel?
>
>I ask because somehow you'd have to have your Bose AM-5's and this
>bass shaker being fed.
>
>First, if the bass shaker is 4ohms, and only your left or right
>channel can possibly drive that low of an impedance, you then only
>have two choices as to where to place it.
>
>BUT, don't you also have to hook up your Bose AM5's?
>
>If you already have a 4ohm bass shaker load hanging off any channel of
>your Sony, and your amp specs say that 4ohms is the minimum impedance
>it can safely drive, adding any other speaker on that same channel
>will bring it below that minimum, and you risk damaging your amp
>(worst case), reducing its life (due to added thermal stress), or
>sending it into thermal shutdown in very short order (assuming a well
>design overload protection circuit).
>
>I'm afraid I can't see how you can safely use this device with your
>receiver. You will need an external power amp, or a powered shaker.

[Todd H.]

user1 > writes:

> According to the wiring instructions on teh Aura site, it says to take
> the subwoofer output to an amp, and from the amp to the bass shaker.
> The Sony has 2 sets of speaker outputs. I have the Bose going through
> the 1st set of outputs. From what it sounds like (and from what I was
> thinking) it would be a bad idea for me to run the bass shaker off the
> 2nd set of speaker outputs.

Correct. BEcause the 8 ohm Bose's would be in parallel with the 4ohm
bass shaker resulting in a 2.66ohm load that your amp wouldn't like.

> I guess I'll have to get a cheap amp to run it off the subwoofer
> output.

Or... choose a _powered_ bass shaker that takes a preamp level signal
into it. It has its own amp built into it.



--
/"\ ASCII Ribbon Campaign | Todd H
\ / | http://www.toddh.net/
X Promoting good netiquette | http://triplethreatband.com/
/ \ http://www.toddh.net/netiquette/ | "4 lines suffice."

[Mark D. Zacharias]

> Thanks for all your input... it saves me from burning out the receiver
> and having to get a new one.
>

Thank you for exhibiting more intelligent respect for technical issues than
we often see from non-tech type people. This has been a pleasurable
exchange.

Mark Z.





"user1" > wrote in message
...
> According to the wiring instructions on teh Aura site, it says to take
> the subwoofer output to an amp, and from the amp to the bass shaker.
> The Sony has 2 sets of speaker outputs. I have the Bose going through
> the 1st set of outputs. From what it sounds like (and from what I was
> thinking) it would be a bad idea for me to run the bass shaker off the
> 2nd set of speaker outputs.
>
> I guess I'll have to get a cheap amp to run it off the subwoofer
> output.
>
> Thanks for all your input... it saves me from burning out the receiver
> and having to get a new one.
>
>
> On 14 Aug 2003 07:19:33 -0500, (Todd H.) wrote:
>
> >user1 > writes:
> >> Sorry about that. I've got a Sony STR-DE925. It can be switched to
> >> 4 Ohms, but the Bose AM-5? (or should I say blows) that I have is
> >> rated for 8 Ohms.or 4 Ohms for only the right and left channel.
> >
> >How are you planning on hooking this up? Where are you planning to
> >plug this bass shaker in and are there any other speakers already
> >being driven by that channel?
> >
> >I ask because somehow you'd have to have your Bose AM-5's and this
> >bass shaker being fed.
> >
> >First, if the bass shaker is 4ohms, and only your left or right
> >channel can possibly drive that low of an impedance, you then only
> >have two choices as to where to place it.
> >
> >BUT, don't you also have to hook up your Bose AM5's?
> >
> >If you already have a 4ohm bass shaker load hanging off any channel of
> >your Sony, and your amp specs say that 4ohms is the minimum impedance
> >it can safely drive, adding any other speaker on that same channel
> >will bring it below that minimum, and you risk damaging your amp
> >(worst case), reducing its life (due to added thermal stress), or
> >sending it into thermal shutdown in very short order (assuming a well
> >design overload protection circuit).
> >
> >I'm afraid I can't see how you can safely use this device with your
> >receiver. You will need an external power amp, or a powered shaker.
>
>