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BlinkRockr41 09-09-2004 08:01 PM

Hey I've got some more questions. We're looking at buying a mixer and power amp seperate now to possibly save money. The reason for this is because we only need 2 mic inputs so we could buy a really small mixer for cheap. OK first of all you have to match the ohms of the power amp to the ohms of the speaker, right? So if you need 400W (or 200 for each speaker) you want a power amp with 200W/ch @ 8 ohms, and two 8 ohm speakers, right? But if its 200W @ 4 ohms, can you run that into 2 8 ohm speakers? I guess im asking how the ohmage is supposed to match up.

Aes820 09-09-2004 08:48 PM

The ohms should match up.
If you've got a 2x200 @ 4 ohms.
You should use it with 200 watt, 4 ohms speakers.

You can run it through 8 ohms speakers.
But with the higher impedence of the speakers, the wattage output of the head will be somewhat reduced.
So with a 2x200 watt @ 4 ohms amps through 8 ohms speakers. You may be only getting 2x120 or so watts out of the amp.

There are other options open to you. But I think the simplest and the least expensive thing to do would be to buy a poweramp and a pair of speakers that match.

KissMeIamSh*tFaced 09-10-2004 06:13 PM

This thread should be stickied i think

Aes820 09-11-2004 12:26 AM

[QUOTE=KissMeIamSh*tFaced]This thread should be stickied i think[/QUOTE]
Seconded..
It was at one stage.
It's not up to me tho.

KissMeIamSh*tFaced 09-12-2004 06:48 PM

ok guys... what is the cheapest PA you guys have ever seen? I think i saw one for 500$ once (used) with 4 inputs and two monitors.. something like that

Gremlin 09-13-2004 03:00 AM

$500 used, 4 inputs?

dude, check it.
[url]http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/630130/[/url]
[url]http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/632200/[/url]
[url]http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/608003/[/url]

Those are probably the cheapest you'll find.

KissMeIamSh*tFaced 09-13-2004 05:22 PM

o haha i meant 500$ canadian but yea that would be what 325? And i meant like seen in a pawnshop or a store. so i guess 270$ american would be what i should have said

Aes820 09-13-2004 05:44 PM

[QUOTE=Gremlin]Those are probably the cheapest you'll find.[/QUOTE]
Yep.. Pretty much.

herobehindthemsk 09-13-2004 06:43 PM

KissMeIamSh*tFaced, good band man..good band

KissMeIamSh*tFaced 09-13-2004 08:53 PM

ok well there goes my feeble attempt to start a conversation

PS: Very good man

i'm_soooo_emo 09-16-2004 08:52 AM

my pa is ****e.
 
At the moment i have got a Mcgregor powered mixer (300 watt) that to me looks about 15 years old at the least. And i also have some peavey eurosys III speakers. I have had this for about a year but i am well unhappy with it. It sounds ****E! Do you rekon it'll be the speakers or the mixer that needs replacing coz i can afford to replace both? Whatever i decide to get i'll have a budget of about £400.

HELP!

Aes820 09-16-2004 05:23 PM

Narrow down where the problem is. Because it is either a problem with the speakers or with the PA. Either the speaker cones are damaged, or the PA is rooted.

Try it out the speakers through a differnt PA, and try out the PA with differnt speakers.

But guess is that the PA will be stuffed, seeing as it is so old.
Find out the wattage of the speakers, and get yourself a new powerd mixer to suit.

herobehindthemsk 09-16-2004 07:20 PM

hey aes...my pa just isn't cutting it with only 2 cab's and 1 floor monitor...what do you think would be the CHEAPEST way of making it louder than all the instruments>?....way louder

Aes820 09-16-2004 07:56 PM

Pick the speakers up higher, if they are not already. Get some stands for them.
Speakers at ear height sound louder than speakers pointing at your ankles.

Add on more speakers. Doubling your speaker area will give you a similar increase in loudness as you would get with twice the output power. But, of course, watch your ohm loading.

Is the floor monitor ran off the same powered mixer as the FOHs? How is it setup?
You could perhaps use an independant powered speaker for the floor monitor. And dedicate the power to the FOHs. Perhaps you could even bridge it?

You could sell it and buy a larger PA. And of course there are many other options. But it depends on what you've got. What have you got at the moment?

moaner 09-17-2004 09:37 AM

Aes, is there any real disadvantage to using a passive mixer into our PA? Our PA has 2 mic and 2 aux (presumably line, that's the way we've used them) inputs. Could we have a Passive mixer for all the amp mics going into a passive mixer into one mic input, and the vocal mic into the other? and put the line outs of the keyboards into the aux inputs? This would be extremely convinient as when we upgraded our PA we could get a 4 channel one- there seems to be a huge gap between the prices of 4 channel PAs and 6-8.

Aes820 09-17-2004 10:06 AM

Yeah. Run the main outputs of the passive mixer into the aux inputs of your powered mixer.

Run all you mics and line level signals into the passive mixer (or into the two spare mic inputs on the powered mixer if needs be). That should be fine.

But, as always. Keep an eye on how you've got your levels set. Watch for clipping, excess noise, etc.

moaner 09-17-2004 10:24 AM

thanks

man, you're quick...

herobehindthemsk 09-17-2004 01:13 PM

[QUOTE=Aes820]Pick the speakers up higher, if they are not already. Get some stands for them.
Speakers at ear height sound louder than speakers pointing at your ankles.

Add on more speakers. Doubling your speaker area will give you a similar increase in loudness as you would get with twice the output power. But, of course, watch your ohm loading.

Is the floor monitor ran off the same powered mixer as the FOHs? How is it setup?
You could perhaps use an independant powered speaker for the floor monitor. And dedicate the power to the FOHs. Perhaps you could even bridge it?

You could sell it and buy a larger PA. And of course there are many other options. But it depends on what you've got. What have you got at the moment?[/QUOTE]


right now ...its a squier 4 pa with 80 watt mixer with 2 i think 12 inch cabs with a 10 inch floor monitor

Aes820 09-17-2004 08:47 PM

80 watts, hmm.. Yeah that probably wont last you too long.

Just see if you can stick it through (using those above mentioned methods) with it until you can afford to upgrade.

For an upgrade, a 2x200 watt powered mixer and a couple of speakers would probably be your best bet.
And you could always keep the 2x80 setup to use as monitors.

herobehindthemsk 09-17-2004 09:10 PM

would mic pre-amps help any..don't they give the kind of boost a guitar efx petal gives a guitar>? or no?

Aes820 09-17-2004 09:33 PM

They may boost your loudness a little bit. If you set them properly.
But they can introduce unwanted distortion into your sound if you are not careful with how they are set up.

You can definately give it a try if you wish. Although it is not a long term solution.

moaner 09-18-2004 05:05 PM

Sorry to bother you aes...

were i to use 4ohm outputs of my pa into 8ohm spekaers, would this blow them/ the amp? The amp is only 60w, whereas the speakers are 75w each. with them safe in terms of power rating, is it an issue?

Aes820 09-18-2004 08:53 PM

Running 4 ohm outputs through 8 ohm speakers mean that the wattage output of the amp will be slightly reduced.
So if the amp is 60 watts at 4 ohms, then it may only be 40 or so watts while through 8 ohms.
So, power wise, it is not an issue at all.

To get the most out of your PA it is usually best to match your ohm loadings at all times. But, just be sure of the way that your PA works. Running two 8 ohm speakers in parrallel off the one output will have a total load of 4 ohms, for example.
And often, many of those little 4 input mixers are infact just mono PAs, and not true stereo.

moaner 09-19-2004 03:49 AM

I severely doubt its true stereo, but it has 2 4ohm outputs and the speakers i've found are 8 ohm

Its just we were thinking of using it for small venues and then in the future, we'll upgrade everything and use that as our monitoring setup. But 60w wasn't a lot in the first place, will 40w be any good at all, for even the smallest venues?

here they are
[url]http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=23794&item=3749255399&rd=1[/url]

would this plan work? I'm just trying to picture if it was just me with a 40w guitar amp what kinda venue i'd be able to play comfortably. with speaker stands, this might be alright.

Aes820 09-19-2004 04:09 AM

Yeah. That's what I was thinking.
And in that case you will be getting the full 60 watts out of the PA. But still, that isn't a whole lot.
They should be alright for practising, and perhaps 'backyard party' sized gigs. But probably not much more
Getting them up onto stands may help a bit. But you really would be better off, in the long run, with a higher powered PA.

With regards to upgrading the whole lot and keeping them for monitors. That is a good idea. And that is what i have done. My older PA is one of those little 4 input 100 watt powered mixers. And since I have now upgraded into these 2x300 watt biamped speakers. I keep the 100 watter and it's speakers for monitoring.

i'm_soooo_emo 09-19-2004 04:24 AM

IN my rehersal room at the moment i have a 300watt pa and speakers (dunno the watt of them but its irelevant anyway. But we are soon gonna start sharing with another band and they have a better pa than mine. But my plan is to use MY pa (the crap one) as a monitoring thing and this is how i plan on doing it. Will this work.......?

I will set the good pa up as normal but then from an output on this pa i will then run a jack to jack lead to an input on the crappy pa and use the crappy speakers as monitors. This way i will be able to turn the volume of the monitors up and down.

Any good?

moaner 09-19-2004 04:42 AM

what a convinient time to ask...

look up.

Aes820 09-19-2004 06:28 PM

Yeah. That'll work fine. If the good PA has got a line out, or an Aux output. You can run that into the input on the older PA.

DO NOT run a cable from the speaker outputs of the good PA into the older one. This wont be any good for either PA.

BlinkRockr41 09-20-2004 05:10 PM

Hi, I asked some questions before about how the ohmage was supposed to match up between the power amp and the speakers. I have a few more questions. Ok I understand the the ohmage of the power amp has to be equal to the ohmage of the speaker. And I see alot of power amps that run on 8, 4, and even 2 ohms. So that would mean if I ran the power amp on 2 ohms, I just need some 2 ohm speakers. The problem is, looking throught Musician'sFriend they dont tell you the ohmage of alot of the speakers in there, and the ones they do, all say 8 ohms. So are all speakers 8 ohms? They couldn't all be 8 right, otherwise how could power amps run on 2 ohms? And if not, how do I figure out the ohmage if it doesnt tell me? One other thing, when a power amp is bridged, you have a mono signal, right? So can you only drive one speaker when a power amp is bridged? If so, do you get plenty of sound w/ one speaker? I assume you would because of the increased wattage by bridging. Thanks for the help

Aes820 09-20-2004 06:00 PM

1st question. Ohms.

Some poweramps have the abilty to be run at 2 ohms. Yet many (but not all) speakers are only 8 ohms. But. You can wire multiple speakers together. So you can have two 8 ohm speaker cabinets wired next to each other (in parrallel) where the total load of these two speakers would be 4 ohms.

Two 8 ohm speakers (or groups of speakers) in parrallel = 4 ohms.
Two 4 ohm speakers (or groups of speakers) in parrallel = 2 ohms.

So, given this, you can connect up additional speaker cabinets onto the one PA to suit different ohm loadings. Knowing that more speaker area is a good way of increasing loudness. As doubling your speaker area will give you a similar increase in decibels as you would get with an amp with twice the wattage.

Read this article for information about speaker impedence:
[url]http://www.peavey.com/support/technotes/concepts/impedance.cfm[/url]

2nd question. bridging.
When you bridge a poweramp. It is like taking both the left and right channels and combining them into the one mono channel. So a 2x200 watt amp will become a 1x400 watt amp when it is bridged.

Another thing you have to think about, when you bridge the poweramp, you have to double the speaker ohms.
So if your amps is 2x 200 watts @ 4 ohms. Then when bridged it'll be 1x 400 watts while at 8 ohms.

Bridging a poweramp is commonly done when using the poweramp do drive a subwoofer (in a biamped / triamped setup). Because of the lower frequencies, subwoofers require the extra wattage to stay clear and undistorted. And also, because bass frequencies are omnidirectional (you dont need a left and right channel). It doesnt matter that you dont have a left and right channel.

So, if you are thinking of adding on a subwoofer to your setup. Get back to me. But for now and for your specific situation, I dont think there will be any advantage in bridging your PA. Just leave it how it is.


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