First P.A system

  • Thread starter Thread starter Idgeit
  • Start date Start date
Never heard of them.
The amp looks exactly like a Mackie 1400i, and the speakers look like PAS boxes, for what it's worth.
 
I mean the set up of it, 2x450W/8Ohm amp with 300W RMS, 8 ohms speakers, would that be ok, or would it have to much power?
 
Aaahh..
Yes, that set up will indeed deliver that amount of power. Just make sure you do not drive the amp too hard, as you could damage your speakers.

Conventional wisdom is to have an amp that can deliver more power than your speakers are rated for, but if you keep the amp from clipping, you should be fine.
 
ohhh k thanks alot for that :)

One last question, what is the actuall difference in 40 and 80 ohms?



Thanks again

- Idgeit
 
C'mon Chess, nobody can set 'em up any better than that!
 
Idgeit said:
ohhh k thanks alot for that :)

One last question, what is the actuall difference in 40 and 80 ohms?



Thanks again

- Idgeit
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40 ohms. :)


It's 4 ohms and 8 ohms, not 40 and 80. It looks confusing, I'll give you that.
It's just written funny. 4ohms and 8ohms.

It's the impedance rating of the speaker.

A lower impedance speaker lets more current flow from the amp, and more power can be generated.

A 4ohm speaker will let about twice as much power be generated as an 8ohm speaker.

Here is the maybe confusing part: when you hook to speaker cabs together, the total impedance drops.

Two 8 ohm boxes hooked together will give you 4ohms. So on that amp, you can hook two 8ohm boxes on each side. The amp can't tell the difference between one 4ohm box and two 8ohm boxes hooked together.

So you can have one 8ohm box per side, each one having 450W available, or two 8ohm boxes per side, each having 350W available.

Total power available with one 8ohm per side: 900W
Total power available with two 8ohm per side: 1400W

It won't be a lot louder, but you can get a lot better coverage with four speakers as opposed to two.

It's a little more complicated, but that's the basic idea.
 
apl said:
Carvin makes good PA amps and speakers.
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OK amps and powered mixers, worst speakers ever, IMO. And most of it is unavailable in Europe anyway, I think.
 
boingoman said:
...unavailable in Europe...
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Oops, didn't catch that. Probably pricey over there since they have to add the distributor markup.
 
apl said:
Oops, didn't catch that. Probably pricey over there since they have to add the distributor markup.
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Not to mention no factory within 7,500 miles. Shipping for warranties gets to be a drag. :)

And I wanted to add that their top line PA stuff has gotten much better, and even has grudging acceptance.

For lower end, I'd stick with Mackie, PAS, Peavey, Yamaha, or the like, though.
 
Im still pondering on a few bits,

2x450W/8 ohms amp with two 300W RMS, 8 ohms speakers,

What is the over all RMS of that setup gonna be?


Thanks

- Idgeit
 
boingoman said:
40 ohms. :).

So you can have one 8ohm box per side, each one having 450W available, or two 8ohm boxes per side, each having 350W available.

Total power available with one 8ohm per side: 900W
Total power available with two 8ohm per side: 1400W

It won't be a lot louder, but you can get a lot better coverage with four speakers as opposed to two.

It's a little more complicated, but that's the basic idea.
Click to expand...

It will be quite a lot louder as you get a further increase of 3db free because of mutual radiation.

Tony
 
wilkee said:
It will be quite a lot louder as you get a further increase of 3db free because of mutual radiation.

Tony
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If you are speaking of acoustic coupling, it generally only happens below about 400hz unless the speakers are designed to couple at higher frequencies and are arrayed properly.

Coupling would surely help you get some extra low-end thump out of say, two 15"/horn cabs per side no matter what, but you gotta be careful to not overlap your horns to avoid comb filtering. Since they won't cover the same area, the SPL of the highs won't be greater at any listening point, but coverage will be wider.

I've taken advantage of this at DJ gigs with only two speakers. Putting them next to each other takes advantage of low-end coupling. You get a little more before you reach for the EQ.

I also find I usually have to cut some low-mids, since they couple as well, and tend to muddy things up.

Using the system above, 2 boxes per side could actually result in less max SPL per coverage zone in the mids/highs, as each box has a max of 350W available, as opposed to 450. :cool:

Thankfully, most of us are looking for more low-end.

Even if the boxes were perfectly coupled and focused on a single area, max SPL increase would be 4.6 db. +3db for double the boxes, and +1.6 db for the extra 500W.
 
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lol i dont know how i missed that when i was reading over the thread,

thanks

- Idgeit
 
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