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Driving speakers in series and/or parallel

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Anonymous
April 25, 2005 5:48:40 PM

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

This general issue has probably been discussed ad nauseum, but I want
to make sure my specific idea isn't going to blow up the Earth.

I have a small PA amp driving a single 8 ohm speaker that I use for
security monitoring in my retail store (mic in store, speaker in
office). I want to expand the system by adding 2 more speakers in
other areas.

If I go out and buy 2 cheap 4 ohm speakers, can I connect all three ( 8
+ 4 + 4 ) in series to my amps 16 ohm terminals?

Quality is not a big concern here (as long as it's not ridiculous). I
just want to avoid damaging the amp (or as stated above, destroying the
planet).

BTW the amp as terminals for 4 ohm, 8 ohm, 16 ohm and 70V connections.
Is there a better solution than what I'm suggesting?

Thanks in advance for all wisdom and advice.
David
April 26, 2005 2:04:51 AM

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

In article <1114462120.772317.76640@z14g2000cwz.googlegroups.com>,
"David Jennings" <davjen@cableone.net> wrote:

> This general issue has probably been discussed ad nauseum, but I want
> to make sure my specific idea isn't going to blow up the Earth.
>
> I have a small PA amp driving a single 8 ohm speaker that I use for
> security monitoring in my retail store (mic in store, speaker in
> office). I want to expand the system by adding 2 more speakers in
> other areas.
>
> If I go out and buy 2 cheap 4 ohm speakers, can I connect all three ( 8
> + 4 + 4 ) in series to my amps 16 ohm terminals?

Doing this will work, but the two 4ohm speakers in series will see half
the wattage each as opposed to the single 8ohm speaker. Which may or may
not be a problem.

>
> Quality is not a big concern here (as long as it's not ridiculous). I
> just want to avoid damaging the amp (or as stated above, destroying the
> planet).
>
> BTW the amp as terminals for 4 ohm, 8 ohm, 16 ohm and 70V connections.
> Is there a better solution than what I'm suggesting?

IMO Investing in the 70V setup will do what you're asking without the
impedance issues. Especially if you plan to upgrade more in the future.

>
> Thanks in advance for all wisdom and advice.
> David
>

hth,

--
Cyrus

*coughcasaucedoprodigynetcough*
Anonymous
April 26, 2005 2:25:52 AM

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

On 25 Apr 2005 13:48:40 -0700, "David Jennings" <davjen@cableone.net>
wrote:

>This general issue has probably been discussed ad nauseum, but I want
>to make sure my specific idea isn't going to blow up the Earth.
>
>I have a small PA amp driving a single 8 ohm speaker that I use for
>security monitoring in my retail store (mic in store, speaker in
>office). I want to expand the system by adding 2 more speakers in
>other areas.
>
>If I go out and buy 2 cheap 4 ohm speakers, can I connect all three ( 8
>+ 4 + 4 ) in series to my amps 16 ohm terminals?
>
>Quality is not a big concern here (as long as it's not ridiculous). I
>just want to avoid damaging the amp (or as stated above, destroying the
>planet).
>
>BTW the amp as terminals for 4 ohm, 8 ohm, 16 ohm and 70V connections.
>Is there a better solution than what I'm suggesting?
>
>Thanks in advance for all wisdom and advice.
>David
Well you might have speaker efficiency (loudness) issues either way.
Another issue in series is power HANDLING capacity of the 8 ohm vs the
2 @ 4 ohm (in series, 4 ohm w+ 4 ohm w = 8ohm W). If they are
different, I woul series the 4's and parallel the with 8, connected to
the 4 ohm tap.

The 70V output has lots of potential (ok, good pun also) for level
adjustment but needs a 70.7 V to Speaker transformer at each speaker.

, _
, | \ MKA: Steve Urbach
, | )erek No JUNK in my email please
, ____|_/ragonsclaw dragonsclawJUNK@JUNKmindspring.com
, / / / Running United Devices "Cure For Cancer" Project 24/7 Have you helped? http://www.grid.org
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Anonymous
April 26, 2005 2:13:21 PM

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

On 25 Apr 2005 13:48:40 -0700, "David Jennings" <davjen@cableone.net>
wrote:

>This general issue has probably been discussed ad nauseum, but I want
>to make sure my specific idea isn't going to blow up the Earth.
>
>I have a small PA amp driving a single 8 ohm speaker that I use for
>security monitoring in my retail store (mic in store, speaker in
>office). I want to expand the system by adding 2 more speakers in
>other areas.
>
>If I go out and buy 2 cheap 4 ohm speakers, can I connect all three ( 8
>+ 4 + 4 ) in series to my amps 16 ohm terminals?

You can try that. Or, if you connect the two new 4 ohm speakers in
series they will present 8 ohms. Parallel the existing 8 ohm speaker
to that, the amp will see 4 ohms.

Your amp probably won't care much what you connect. Your problem
will arise in the differing volumes you are likely to get from each
speaker.

The real answer to this is to use the 70 ohm line. Get a price on
three 70 ohm speakers, maybe with included volume controls. If you
can do this at an acceptable price, fine.

>
>Quality is not a big concern here (as long as it's not ridiculous). I
>just want to avoid damaging the amp (or as stated above, destroying the
>planet).
>
>BTW the amp as terminals for 4 ohm, 8 ohm, 16 ohm and 70V connections.
>Is there a better solution than what I'm suggesting?
>
>Thanks in advance for all wisdom and advice.
>David
Anonymous
April 27, 2005 1:19:07 AM

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

Laurence
70 Volts LINE busbar, not 70 Ohms!

David
I suggest you keep the 8 Ohm unit as is. If you go this extra route, you'll
need 2 PA loudspeaker stations, usually 4 or 8 Ohms, 5 Watts, but fitted
with a 70/100V line xformer - and a volume control is advised for zone
loudness adjustments.
You may even find them 2nd-hand. These high-Z devices can be daisy-chained
with cheapo telephone pair wire. You might want to add more one day.

"Laurence Payne" <lp@laurenceNOSPAMpayne.freeserve.co.uk> wrote in message
news:v21s615b0cdmtupg105uo8icq8ke1kmrpk@4ax.com...
> On 25 Apr 2005 13:48:40 -0700, "David Jennings" <davjen@cableone.net>
> wrote:
>
>>This general issue has probably been discussed ad nauseum, but I want
>>to make sure my specific idea isn't going to blow up the Earth.
>>
>>I have a small PA amp driving a single 8 ohm speaker that I use for
>>security monitoring in my retail store (mic in store, speaker in
>>office). I want to expand the system by adding 2 more speakers in
>>other areas.
>>
>>If I go out and buy 2 cheap 4 ohm speakers, can I connect all three ( 8
>>+ 4 + 4 ) in series to my amps 16 ohm terminals?
>
> You can try that. Or, if you connect the two new 4 ohm speakers in
> series they will present 8 ohms. Parallel the existing 8 ohm speaker
> to that, the amp will see 4 ohms.
>
> Your amp probably won't care much what you connect. Your problem
> will arise in the differing volumes you are likely to get from each
> speaker.
>
> The real answer to this is to use the 70 ohm line. Get a price on
> three 70 ohm speakers, maybe with included volume controls. If you
> can do this at an acceptable price, fine.
>
>>
>>Quality is not a big concern here (as long as it's not ridiculous). I
>>just want to avoid damaging the amp (or as stated above, destroying the
>>planet).
>>
>>BTW the amp as terminals for 4 ohm, 8 ohm, 16 ohm and 70V connections.
>>Is there a better solution than what I'm suggesting?
>>
>>Thanks in advance for all wisdom and advice.
>>David
>
Anonymous
April 27, 2005 7:09:31 AM

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

On Tue, 26 Apr 2005 21:19:07 GMT, "Jim Gregory"
<jim.greg@ntlworld.com> wrote:

>Laurence
>70 Volts LINE busbar, not 70 Ohms!

Indeed. My brainfart.
!