Gary Rodgers wrote
"Sanitarium" wrote in message
...
| I agree with Mark.
|
| Make sure your subs are wired for an impedence load the head unit can
| handle.

If the subs are running off of an external amp, what difference will the way
they are wired to the amp make as far as the head unit is concerned?

| When you wire up a 2 ohm speaker load to an amp bridged mono, the amp
| "sees" a 1 ohm load.

No it doesn't.

| Furthermore, a 4 ohm speaker load to an amp
| bridged mono, the amp will really "see" 2 ohms.

No it won't.

| If this is the scenario
| make sure the amp can handle lower impedence loads.
|
| Garrett
|
snip

Can you 'splain this to me? A load is a load. If'n yer puttin' 2 ohm
load
(2 -4's wired in parallel), the amp sees 2 ohms. If yer puttin a single
4-ohm speaker (sub), the amp "sees" 4 ohms...because that's what the load
is.

Or am I missing something?

You aren't missing something ... Sanatarium is. He misunderstands the theory
behind bridging an amp.

For a given amp the following is true :
Amp "A" is rated for 50W x 2 @ 4ohms, 100W x 2 @ 2ohms (minimum impedance)
when you bridge the amp, 195W x 1 @ 4ohm (minimum impedance)

notice that when you bridge the amp the minimum impedance is higher. Bottom
line is, if you wired a pair of 4ohm speakers in parallel and then run the
amp bridge you will have a 2ohm load which the amp is not rated to handle.
In this example, you have 3 obvious options :

1) speakers in parallel running off 1 side of the amp (amp not bridged)
results in 100W @ 2ohms giving each speaker 50W
2) speakers in stereo on their own channels (amp is in stereo) results in
50W x 2 @ 4ohms giving each speaker 50W
3) speakers in series amp bridged results in ~100W @ 8ohms giving each
speaker 50W

This is why some degree of planning is important when choosing an amp for
the subs, or subs for an amp. Some would argue that running subs in stereo
is a bad idea ... I don't have an opinion on it. It is mostly for
illustration, but is very applicable for speaker systems that aren't subs.

--
Regards,
Dan Snooks