Some amp questions from a retard

pdadda

pdadda

Captain Sea Boots
I have been using the crappy powered mixer that this local bar provides up until now. But I am looking into buying a minimal but non-crappy PA system. Most places I will be playing will not have more than 100 people or so (indoors). When looking at amps, I see that they rate the wattage per channel at different ohmages. What does this really mean? Should you set them at 2 ohms, 4 0hms, 8 ohms, bridged? I am quite sure this is a dumb question, but it will help me figure out which amp to buy. Even a link to a website with such info would be great. Thanks.
 
pdadda said:
I have been using the crappy powered mixer that this local bar provides up until now. But I am looking into buying a minimal but non-crappy PA system. Most places I will be playing will not have more than 100 people or so (indoors). When looking at amps, I see that they rate the wattage per channel at different ohmages. What does this really mean? Should you set them at 2 ohms, 4 0hms, 8 ohms, bridged? I am quite sure this is a dumb question, but it will help me figure out which amp to buy. Even a link to a website with such info would be great. Thanks.
Click to expand...
Not a Dumb Question
The ohmage is determined by the type and number of speaker cabs being used. Cabs come different ohms; 16,8,4 and, rarely, 2 ohms. If your amp say it can run 200 watts at 8 ohms, then you can run two 16 ohm cabs or one 8 ohm to get the 200 watts. If it says 200 watts at 2 ohms, then you can run one 2 ohms, two 4 ohms, four 8 ohms or 8 16 ohms. And on some tube amps you also have to select which ohmage you're going to run, though I've never run into one. If the amp is stereo, this applies to each side. Also, you can bridge most Stereo power amps, giving you a mono signal, but a increase in power. Most bass players do this, but I don't think it usefully for PA. And I also don't run my amps at 2 ohms; I like a little safety margin. Did all of that make any sense?
 
this makes alot of sense, thanks !
now, why don't live PA engineers use the bridged mono mode ?
since most live PA mixes are kinda Mono.....then whats wrong with using the bridged mode ?
what do you loose? a tiny little bit of stereo image that probably won't even benoticed by the crowd ?
or is there more...

and now that we are talking about AMPS for small FOH systems,
can you name a few brands that do a fine job?
i see that there are Many amps on the market that produce lots of watts,
but i just don't know much about "Live gear",
brands i should check out,,,brands i should stay away from...
popular modals for clubs or venues that can host a maximum of 300 people...

...edit....
additional question:

so if i get it right, then the Higher the Ohm on your speakers, "the better",
and the lower the OHM on your amp, the better,
since this gives you alot more connection possibilities ?
...so you only gotto make sure your Speakers have a higher Ohm-age than the amp.......
Real curious !
cheers,
earworm
 
If you are using more than one speaker, bridged mono doesn't do you any good. (send the same signal to both sides of a power amp and hook one speaker to each side) If you only have one speaker that will handle the power, bridged mono will do what it is supposed to.
 
interesting,,,i'm learning,
and next month i'm gonna start hunting for some amps to do small live gigs,
so any recommendations for Brands...
whats junk,,,what's nice// cause for LIVE i don't really know where to start looking...

thanx
 
earworm said:
this makes alot of sense, thanks !


and now that we are talking about AMPS for small FOH systems,
can you name a few brands that do a fine job?
i see that there are Many amps on the market that produce lots of watts,
but i just don't know much about "Live gear",
brands i should check out,,,brands i should stay away from...
popular modals for clubs or venues that can host a maximum of 300 people...
Click to expand...
Yamaha, Soundcarft, Mackie and some Behringer, if you have to watch the bills.
...edit....
additional question:

so if i get it right, then the Higher the Ohm on your speakers, "the better",
and the lower the OHM on your amp, the better,
since this gives you alot more connection possibilities ?
...so you only gotto make sure your Speakers have a higher Ohm-age than the amp.......
Real curious !
cheers,
earworm
Click to expand...
Ok, the other side of the coin is this; 16 ohm speaker aren't as loud as 8 ohms, 8 ohm aren't as loud 4 ohm, 4 ohms aren't loud as 2 ohm. I'd said 8 ohm cab are sorta standard for small PA systems. Now there is some other complicated stuff regarding SP and surface area and other esoteric s**t. But, I'm not the one to speak on that. This is just practical experience. And most amps will adjust to whatever ohmage speaker load you're running. But, if you drop the load too low, you're risking burning the head, I mean FIRE!!! Flames, smoke, the whole lot.
Here's a few small package's at Musician's Friend; Sweetwater, Zzounds and others have similar packages.
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/631362/
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/630119/
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/605257/

And, you get what you pay for.


:)
 
OK, I have about $1000 to start building my PA. I was thinking of:
Yamaha MG 16/4 mixer
JBL JRX 115
JBL JRX 112M
Crown XLS 402 or QSC rmx 850
That would run me just a bit over budget. What do you think? This is mostly for indoor stuff, no more than 100-150 people. If I only have the money for one speaker and one monitor or two speakers, which would you recommend? I figured I would use one as a monitor until we can buy more stuff in a few months.
 
Definitely, two speakers. You need to get the wide spread.
Get 2 of the JBL JRX 115s
that'll get you started.
 
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You think the JBL's are any better than the Yamaha Club speakers? I had looked at the Peavey PV-215's for the double 15'' speakers. Plus they're cheap. How do those sound? I hope to go listen to all these in a week or so, and I'll post my opinions.
 
pdadda said:
You think the JBL's are any better than the Yamaha Club speakers? I had looked at the Peavey PV-215's for the double 15'' speakers. Plus they're cheap. How do those sound? I hope to go listen to all these in a week or so, and I'll post my opinions.
Click to expand...
I would think, just judging by brands, the JBL's would sound best, The Peavey's the loudest.
 
I'm biased toward QSC because I have one. But, both are quality products. Either should perform well for you.
 
OK, change of plan. I talked to my bandmates and couldn't convince them that this was worth the money right now. They felt more comfortable buying a powered mixer and 2 speakers for our first PA setup, which is fine. At the main place we currently play, we only use two inputs on their powered mixer (two vocal mics). We came to a compromise on the Yamaha EMX66M. Any opinions. They also wanted to start out with smaller speakers (2 Peavey PV115's). Maybe my goals were too lofty for how much money we are currently making. Neither of them want to buy anything used either. I disagree, but that's what bands do best.
 
Let's see if I have this right. The EMX66M has 2 300W amps (rated at 4ohms). So if I am using 8ohm speakers, could I get a total (program) of 300W out (non-bridged)? Or did I totally screw that up?
 
now, a total of 300 Watt rms,
thats 150 on each side

thats barely enough for 150 people in a small place, no ?

what if you want to enforce sound in a bigger gymnasium, for about 300 people

will 2 3-way FOH speakers of about 300 Watt each do?
 
pdadda, that's exactly what I use. Yammy EMX66M. Pretty clean for a powered mixer. I'm running it to a pair of Peavey SP2's though. Got lucky on the speakers, bought them used for $100 each. I have a 4 -pc band, and it's adequate for small and medium size venues. In fact everyone is going direct. No stage amps. I go into a POD to the board, and the other guitar player and bass player have Behringer Vamps and bass V-amps respectively. I also put the kick drum and 2 vocal mics into the mixer and in the process tie up all 6 channels but it holds up fine, the speakers help. I put one speaker in front of the stage and the other aimed either across the stage or in back of the stage as a monitor that still gets to the 'house'. Not exactly the best setup but, without stage amps and floor monitors we can squeeze in to some small areas and still pump out a good bit of sound. One more thing, I don't use the effects on the Yammy, I bring along a 1/3 rack size Alesis Nanoverb. Not the best effects processor ever but waaaaay better effects than you get on most powered mixers and more versatile.

BTW, I do run out of both mains and not bridge mono unless I'm doing a solo gig with one speaker.
 
Since I started this thread, I have gone in a new direction because of deals on used gear. So far, my band purchased 2 yamaha S-15e's with stands and a mackie sr24-4. Total so far=$600. Now we just need to buy an amp.
 
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