Finally getting a real Gigging PA... maybe.

Volitions Advocate

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1,239
But I need help figuring some stuff out.

My friend had this stuff for years and he never used it.  To make a long convoluted story short. he was in a band who used it. then the band broke up, but it stayed with this singer, who starteda  new band and used it, then that band broke up and he wasn't part of it anymore, then the guys he played with started a new band and ended up with the stuff and my friend just barely got it back after 2 years of not seeming to care much about it.  He'll let it go for less than 1K, if we want it, but theres some things I need to complete it also.

Its all old. I think mostly 80s stuff.  The main speakers are "Pyle Pro" which I think only does Car audio now.  The subs are Peavey, so is the amp. and the mixer is a Mackie.

I'll start with the amp.
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It says its 1100 watts @ 550 a side.  Just in case the pictures are too grainy I'll type out what they all say.

the 2nd picture by the inputs says:
The top left switch: DDT - Enable or Defeat (i have no idea what this is about)
The top right: Bridge or Stereo pretty standard stuff

Then the last Picture by the Outputs:
425 W/4 Ohms 41.2V RMS Per Channel
550 W/2 Ohms 33.1V RMS Per Channel
2 Ohms Minimum Load
Speaker Jacks Paralleled

I understand how the wattage changes with the impedance but I don't know what the Voltage and RMS is all about.

It also says down by the power cord: 120 VAC 60Hz 1200 Watts
Then the main Speakers and the Subs:
n517473612_1168828_4271.jpg
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The Panel for the mains speakers reads:
Power Handling: 1200 Watts
Freq Response 30-20kHz
SPL: 108dB
Impedance: 8 Ohms

I figure the 2 most important values are the impedence and power handling. I have no idea what SPL means.

Panel for the Subs:
Max Power: 700W RMS (program)  350W RMS (53V RMS CONT.)
Impedance 8 Ohms.

I have no idea how to read into this.

The mixer is pretty standard stuff.. Its just dirty. the pots need to be cleaned.  But its in good shape considering what its been through.
n517473612_1168826_3647.jpg


Right now we've got the main speakers hooked up to the amp through channel A in Bridge mode with the cabinets connected in Series.  Apparently thats how they've done it most of the time anyway.  We're not pushing it hard we're just testing it to see if it works and all we've got hooked into it is a couple vocal mics and a keyboard. and it plays nice and loud if we want it do, but we dont really turn it up any louder than being able to hear it above the drums.

I keep hearing OPINIONS about how this should be used but nobody has actually given me any facts or literature to check out.  This strikes me as a good deal though even with the added cost of actually getting the rest. BUT I don't knwo what to get.

Here is what I THINK I need and I'm getting about 2 or 3 pro's with real gear around town to come down to the rehearsal space to check it out too, but i'm trying to gather all the info I need.

As far as I speculate this is what I figure.  I'll trust the 350 watt sign on the back of the subs.  So I can hook up the subs to the amp we've got in stereo and we should be good. thats 550 watts from the amp fed into each speaker cab. (to follow with the old wives tale that you should use a little more power from the amp than what the speakers are rated for) and I'd do this because the main speakers would need a lot more juice to run in stereo (or bridged for that matter) at a volume appropriate for a gig.

So what I would need to buy would be an amp at least capable of pumping out 1200 watts per side to the main speakers and a Crossover for the 2 amps. yes?  We have in-ear monitors so we dont have to worry about wedges and a 3rd amp.

Here is my question.

I've been told by some people (dj's) that you should use an amp rated for about 1.5 times the power of the speaker rating because you can always turn the volume down if you're getting distortion through the speakers, whereas if you have an underpowered amp for the speakers, then the amp might be in trouble.. for some.. arbitrary reason.  So what is the truth?

Thats also not taking into account impedance.  I've noticed as a loose rule of thumb, everytime you double the impedance you halve the wattage.  I saw an amp on ebay that said it was 2400 watts, 1200 a side @ 2 ohms.  so of course If i hooked these 8 ohm speakers into the amp they'd each be getting somewhere around 300 watts each in stereo right?  SO even tho the amp is rated at 1200 a side and the speakers are 1200 watts each.  its really like hooking up a 300 watt amp to 1200 watt speakers. as far as I can figure.  SO if this was the case what would be the problem? aside from not having as much head room to push the volume? is the amp in trouble in this case?  Nobody has been terribly clear in this case.

And like I said I have no idea what the panel on the back of the subs are trying to tell me. is that 700 bridged / 350 stereo or what?

I need some help.  We have a gig in 2 weeks that we're most likely going to be using this equipment for.  This coming saturday I'll be able to buy whatever I need to for it.  But I need to make sure we know its reliable and everything and get a few practices in with it all hooked up to make sure we know how to use it.

Otherwise we'll be renting obviously.

Let me know what i've got right.. if any of it is. and What I should do.
Thanks in advance.  Sorry for the novel length post.
 

jackthehack

Senior member
Messages
5,630
Many of the specs listed above are extremely dubious. I the Pyle Pro speakers are actually 108dB SPL (Sound Pressure Level, measured at 1 meter with 1 watt of input power), I'll kiss your bare ass in Times Square and give you an hour to draw a crowd... Likewise for "Program" wattages ratings.

If you're not using a crossover/seperate subwoofer amp, you can run the main speakers wired parallel to the subwoofers off the amp in stereo mode, theoretically if you believe the wattage ratings that should give you 425 watts per side, a lot more than you'd need for most clubs.

I personnally wouldn't give a grand for that pile, other than the Peavy subs (assuming they're in good condition), the main speakers are junk, that amp could blow at any given moment, and the mixer might need more than just some "pot cleaning".

What other gear do you need and what kind of venues do you play in? You can put together a decent PA of brand new gear for $1000-1500, which would be a much wiser investment. Answer the following and I'm sure there are several people here on the board that can make some reasonable suggestions:

1.) What is the largest venue you'll be likely to play and need to bring your own PA? You can estimate numbers of seats and/or square footage.
2.) How many channels of mixer do you REALLY need?
3.) Primarily what type of music do y'all play?
4.) Do you have a backline of 100watt amps with 4x12s that you play at full volume that the PA has to compete with?
5.) What all "other gear" do you need in addition to the old PA you're looking at?
 
R

RLW

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I have a Peavey power amp I bought in '77 that's still kicking rear. They're indestructible.
 

Volitions Advocate

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Messages
1,239
jackthehack said:
1.) What is the largest venue you'll be likely to play and need to bring your own PA? You can estimate numbers of seats and/or square footage.
2.) How many channels of mixer do you REALLY need?
3.) Primarily what type of music do y'all play?
4.) Do you have a backline of 100watt amps with 4x12s that you play at full volume that the PA has to compete with?
5.) What all "other gear" do you need in addition to the old PA you're looking at?

1. probably... the big pool hall is the biggest bar type venue we'd play with all our own gear. I'd say a dance floor about 30 x 30 feet. plus a lounge/restaurant area with about 15 booths and the area with the pool and snooker tables. with enough room to comfortably fit at least 30 pool tables.
2. We'd use at least half of them. 4 vocal mic's, 2 keyboards, 1 guitar, 1 bass, + drums. The drums we'll probably use a small 8 channel mixer for and give him one channel on the board, he prefers it that way.
3. Im in 2 bands, and the one that woudl actually be using this equipment for gigging would be playing whatever is on the radio.  Mostly Top 40 rock and dance stuff.  A little bit of classic rock but not much.  Pop music mostly. Lots of Synth (the 2nd keyboard is a Korg Microsynth
4. 1 100watt amp w/ 4x12 and a bass amp w/ an 8x10, neither are played at full volume.  I use the ouput volume on my processor to control the volume, I get good breakup at low volumes.  I only need it loud enough to hear clearly.  I dont need 120dB out of the thing.
5. If i were to venture a guess with my limited knowledge.  another power amp at least 2500 watts, and a crossover.  And about 4 or 5 more microphones and all new speaker/mic cables.

If I understand what you're saying about not using a crossover and 2nd power amp (something I didn't consider)
You're telling me that I could use output A to bridge the mains and output B to bridge the subs in stereo mode and get roughly 425 watts out of the whole setup?  Cause if that would be loud enough for a bar then I dont see the problem with what is there already.  Aside form the fact that its old.  But a couple gigs could pay for new equipment if we do it that way.  We're playing little corporate christmas parties and stuff.  Its all rather small bars in town with the exception of 1 or 2 venues.

Thanks for the help.
 

Patrick from Davis

Senior member
Messages
2,197
Just for kicks, RMS stands for Root Mean Square.  It is a statistical way of "averaging" things like outputs from amps where negative numbers are involved in the math (sine waves...).  You can read up on it with the wikipedia link, but for all practical purposes it means that is the average output at that impedance.
Patrick

 

jackthehack

Senior member
Messages
5,630
Were I to set up that PA system:

1.) I assuming that that is a stereo mixer? Not a good pic, but from the controls it looks like it has stereo mix out + a monitor channel.?
2.) Take the left/right outputs from the mixer and plug them into the A/B channels (same as R/L) on the power amp; run 1 speaker cable to the subs, and another to the subs. That will give you stereo sound (always better if running synths/modern keyboards through the mixer).  Npt an optimal setup, but it could work, you could play around with this prior to buying it.

Methinks you're getting hung up on "wattage" ratings. Typical decent PA loudspeakers will be rated around 95-98dB SPL. Add 200 watts real RMS wattage per channel and you're approaching 120dB which is overkill for the types of venues you're going to be playing.

Check out this setup:

This mixer: http://pro-audio.musiciansfriend.com/product/Behringer-Xenyx-1622FX?sku=631271
This amp: http://pro-audio.musiciansfriend.com/product/Crown-XLS-202D-Power-Amplifier?sku=481584
A pair of these: http://pro-audio.musiciansfriend.com/product/Peavey-PV115-2Way-15-Speaker-Cabinet?sku=601389

That's new gear, right at about a grand with a set of speaker stands thrown in. For an extra $100 you can go the Crown XLS 402D amp which would put out another 100w/channel (not a bad idea). You can always add a crossover, another amp and a pair of 18" subs later.

I've used all the suggested gear myself (different older 12 channel model of the Behringer mixer), and for venues similar to where you play it would actually work.  That's assuming you don't actually want to fill the whole 30 pool table hall with loud sound.

Just my 2 cents worth, there are other similar products in the same general price range, just always avoid loudspeakers with any sort of "piezo" tweeters/horns, they blow easily and do not produce/throw high end volume anywhere near as far as a proper horn...
 

mayfly

Senior member
Messages
8,307
From where I sit, there are three questions here:

1 - is this rig a good rig?

2 - is this rig a good deal?

3 - assuming "yes" for the above, what's the best way to run it?

Now the following are just my opinion, so YMMV here, but I've owned/dealt with a lot of PA

1 - is this a good rig?  In my opinion, not really.  The speakers (the most important part) were low end gear back in the day and I don't think they've improved with age.  BTW - Jack the hack has a good thought about the tweeters - if they are not compression drivers don't get them.  Piezo tweeters sound like crap.  The amp is probably ok and will probably last, but it's just not going to sound very good.  Lastly the board.  It's a good one, but it's seen years of use and looks like it was never cased up.  Not a good sign.

2 - is this rig a good deal?  er, no.  You can get a good powered mixer Yorkville setup new for that price.  The Yorkville will sound better, work better, and it has that 2 years "even if you break it" warranty. 

3 - Now - faced with this unit at a show, I'd run it like Jack suggests:  as a stereo pair with each sub connected to each main speaker.  If I had too much bass for a hall, I'd just disconnect one or more of the subs.  I'd also take the amp apart and clean it to prevent thermal failure.  Then i'd take the board apart and clean it too.  Once it was working well, I'd get/build cases for everything and call it a day.  Then I'd probably use it for a bit then sell it and get something better :laughing7:
 

jackthehack

Senior member
Messages
5,630
jackthehack said:
Were I to set up that PA system:

1.) I assuming that that is a stereo mixer? Not a good pic, but from the controls it looks like it has stereo mix out + a monitor channel.?
2.) Take the left/right outputs from the mixer and plug them into the A/B channels (same as R/L) on the power amp; run 1 speaker cable to the subs, and another to the subs. That will give you stereo sound (always better if running synths/modern keyboards through the mixer).  Npt an optimal setup, but it could work, you could play around with this prior to buying it.

Methinks you're getting hung up on "wattage" ratings. Typical decent PA loudspeakers will be rated around 95-98dB SPL. Add 200 watts real RMS wattage per channel and you're approaching 120dB which is overkill for the types of venues you're going to be playing.

Check out this setup:

This mixer: http://pro-audio.musiciansfriend.com/product/Behringer-Xenyx-1622FX?sku=631271
This amp: http://pro-audio.musiciansfriend.com/product/Crown-XLS-202D-Power-Amplifier?sku=481584
A pair of these: http://pro-audio.musiciansfriend.com/product/Peavey-PV115-2Way-15-Speaker-Cabinet?sku=601389

That's new gear, right at about a grand with a set of speaker stands thrown in. For an extra $100 you can go the Crown XLS 402D amp which would put out another 100w/channel (not a bad idea). You can always add a crossover, another amp and a pair of 18" subs later.

I've used all the suggested gear myself (different older 12 channel model of the Behringer mixer), and for venues similar to where you play it would actually work.  That's assuming you don't actually want to fill the whole 30 pool table hall with loud sound.

Just my 2 cents worth, there are other similar products in the same general price range, just always avoid loudspeakers with any sort of "piezo" tweeters/horns, they blow easily and do not produce/throw high end volume anywhere near as far as a proper horn...

Update: To the above, go the $100 extra Crown XLS 402D amp; you can add the subwoofers in the link below for $599 the pair. They have built in passive crossovers so they can simply be run parallel to the PR15s on each channel; you can kick the passive crossover circuit out and put them in bi-amped mode to use a separate stereo crossover/amp, but doubt you'd ever have a need for that...

http://pro-audio.musiciansfriend.com/product/Behringer-B1800X-Pro-EUROLIVE-Subwoofer-Pair?sku=600482
 

simple

Senior member
Staff member
Messages
2,101
I'll add this little tid bit: That Mackie board model was designed (in error) with the two hots reversed, out of phase for your TRS (balanced) jacks. If you are going to use those jacks on that board as balanced, you'll need to build adaptors like I did when I had mine to reverse the two hot wires. Then you can just plug your cables into the short adaptors.
 

Rick

Senior member
Messages
4,530
the only part I like are the peaveys.  The rest of it, forget it, unless they give you some kind of ridiculous deal and it doesn't sound like they are.
 
Messages
8,318
Patrick from Davis said:
Just for kicks, RMS stands for Root Mean Square.  It is a statistical way of "averaging" things like outputs from amps where negative numbers are involved in the math (sine waves...).  You can read up on it with the wikipedia link, but for all practical purposes it means that is the average output at that impedance.
Patrick

Sort of, but AC refers to the sine wave, and speakers are modulated DC.  No negative values, only 0 in this RMS application.
 
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