Conference napalm::guitar

    
    Excuse me if this obvious, but what about the equalization built into
    your mixer.  Assuming that the mics are picking up the bass drums
    then all of the other pieces you've listed sound like they'd work.
    
    Another thing that helps keep the bass SPL up is to compress the bass
    guitar.
    

We like beer bottles to rattle off the table 100 yards away...
:)

      Maybe my initial note wasn't quite clear. The low end sounds good at
    low (um, should say lower) volume. What I meant was the Crown PSA-2 is
    peaking out (up?), I mean the internal power amp comp/limit is kicking 
    in because it's out of juice.
    
      The comment about compressin' the bass is in the ballpark. I guess I
    mean what can I do short of adding another PSA-2 or more 18's to
    augment the low end. 
    
      I do like the LOWWWW frequency end of the spectrum. I'm probably
    asking for concert level low end without enough equipment, but I'd
    like to maximize what I've got.
    
      Maybe I just need some advice on how to adjust the on board (mixer)
    EQ on all the channels that could impact the low end. Maybe some advice
    on which outboard equipment on which inputs would do us the most good
    for the least $'s. Maybe just some advice on the initial setup for the
    mains.
    
      I mean I'm using what I think is a good mic(s) for the kick drums.
    I'm boosting the low end quite a bit on the board (Peavey SRC-2400;
    low frequency EQ band is a 100Hz shelving type), for the kick drums
    that is. I'm puliing a tad off the bass, but even without the bass
    at all the PSA-2 is still peaking.
    
      I got a suggestion to add a 15 or 31 band EQ as an insert on the 
    kick. Does this sound like the best first shot or ... ???
    
    Thanx doods,
    
    Rog 
    

    ...sounds to me like you're just, frankly, running out of zoobs.
    
    Low frequencies will always send my amp into comp/limit at an
    *apparently* much lower SPL than highs. Nature of the beast. EQ'ing
    in some more low just makes it happen faster.
    
    In the words of Tim "The Tool Man" Taylor, you need MORE POWER!!!
    
    Edd

      OK, let me try this from another angle. This system's low end
    component's are pretty close (within an RCH) of givin' us what we
    need in the low end, but I just want to get the most out of it.
    
      Should I:
        a) Quit my bitchin'
        b) Just pull back the EQ on the board
        c) Add another EQ on the kicks
        d) Add a gate to the kicks
        e) Add a comp/limiter to the kicks
        f) Add a comp/limiter to the bass
        g) Pull more low end off everything except the kicks
        h) Add a 4-way Xover (now 3-way) and use another amp and my Ampeg
           SVT cabs
        i) all of the above
        j) none of the above
        k) Any other ideas
    
      Maybe you could give me some idea of how to prioritize the various 
    options as to the best bang for the buck?
    
    Thanx again,
    
    Rog
    

I brought in the Xover (DOD X324) documentation today.
I found a startling revelation - It's not only a 3 way stereo/4 way mono,
but also has a "Low Freq Summed output" - Maybe this is what we should use to
supply a send to the big Crown ?

I beleive that we are working the PSA-2 to hard.  Driving (4) 18" 
not-so-efficient bass bins with one power amp (a 2 ohm load, right?)
is perhaps trying to move too much air (??).  We can experiment perhaps
with using two bins, or trying a big Carver Pm 1.5 in it's place.

Seems to me that while the big Crown is optimized at a 2 ohm load, it's 
still got a *bunch* of coils and paper to move...  Removing a pair of
bins might produce excellent results in MONO mode.

Thougts ?  Comments ?

jc

    Since bass frequencies don't come from a perceived direction, it seems
    to me that running bass bins in stereo is a complete waste.  You'd
    probably have more power to play with by running them in mono.  Save
    the stereo for the mids and highs (if you really think it helps).
    
    gh

Lesse then:

The big boy in mono-mode - will it handle 2 ohms Rog (4-18 inchers) ?

jc (Who 'thinks' that Crown should blast you thru the wall without a flinch)

    I think the idea of adding SVT cabinets is a good one.
    If you are putting out sound through the 18" speakers alone, you may
    lack some of what is needed to give the sound its PUNCH.  You'll get
    rumble, but not that *sock* in the chest feeling.
    
    I have electronic drums and I pump them through an 18" speaker, two 10"
    speakers and a high frequency horn.  I believe that the 10" speakers
    are important to make the sound come alive.  It would be too dull with
    the 18" alone.
    
    	Willy

      I have been using the crossovers summed sub output as a mono input to
    the sub power amp. I am not running the amp in bridged mode though.
    That means the amp is seeing approximately a 4 ohm load per side in
    mono (2-8ohm 18's per side).
    
     Rog

Ummm RE: The SVT cabs...

I think your msising the "rest" of the picture.  This is a three way 
stereo PA, the 18" subs are only low-end, there are Renkus Heinz mid 
and high end drivers also.  

They produce *plenty* of mid and high freq stuff...  It's the 'rattle
your beer off the table' low freqs that are missing...somewhat...
It's certainly NOT a show stopper, but optimization is FUN!
:)

jc

    RE: The SVT cabs...
    
      But if we went to a 4-way... crossover and 1)18's 2)SVT's 3)Renkus
    15's 4)Renkus horns...
    
    Rog

If you go four way, you'll need more amps...If it's more amps you want,
then keep it three way and use a pair of PSA-2's for the four bins.
You wouldn't be able to BREATH out front.

(gasp!)

jc (stayin' on the stage)

      I wonder... anybody out there got any PSA-2's for sale cheap??? :)
    
    Rog

Yeah - and anyone in the Springs are have a FORKLIFT TO MOVE THIS RACK !?!?!

jc (Who is STILL sore from movin that thang!)

    I can't believe people are recommending SVT cabs!  They are quite
    unsuitable for such an application as they would have too much
    distortion.
    
    							Brian

     Hi Rog,
     My 2�.......

      >Maybe my initial note wasn't quite clear. The low end sounds good at
    >low (um, should say lower) volume. What I meant was the Crown PSA-2 is
    >peaking out (up?), I mean the internal power amp comp/limit is kicking 
    >in because it's out of juice.
    
     	You nailed the problem right on the head. You don't need any more
     speakers, you need a bigger amp (I can suggest a few) because it ran
     out of headroom. Other factors can contribute to the problem, though.
     	The PSA2 is more of an esoteric piece of gear, than a brute force
     balls-to-the-wall amp. It has all the specs, but doesn't have great
     power, which is what you need. The PSA2 is 265W @8 ohms/ch, and 380W
     @ 4 ohms/ch, and, I'm not sure, but I think it's 600W @ 2 ohms/ch. That
     isn't enough to do what you wanna do. I know, I had the same problem.
     	I solved it with a bigger amp, 12ga cable to power the rack, 20 amp
     receptacles (not a power strip) to plug the amps into, 12 gauge spkr wire
     with Neutrik Speakon connectors. I never had that problem again.
     BTW, are those Peavey 1-18 cabs 8 ohm or the 4 ohm version? Peavey sells
     field replaceable baskets for all Black Widow drivers. They have new
     Kapton 600W 8 or 4 ohm baskets for ~$100 each. You could make them all
     4 ohm to optimize for the PSA2. I'm not sure that would be best though.

     	Things that contribute to loss of headroom

       1.) Amp rack powered by small gauge extention cord
       2.) All the amps plugged into a "power strip"
       3.) Spkr wire for subs smaller than 14ga
       4.) �" phone plugs on spkr wire
      
     Food for thought....
     Front loaded spkrs are easier to work with than horns, but the
     major drawback is they are not as efficient as horns, folded or
     bent. Output can be 10dB or greater with a folded or bent horn,
     than a front loaded cab with the same model driver. Then there's
     power compression.  That's when the voice coil heats up, output
     drops 3-4dB in each driver. It's inherent in all spkrs with voice coils,
     but not as great in some as in others. All these things can affect
     the headroom of your system.

     >The comment about compressin' the bass is in the ballpark. I guess I

     You mean bass guitar?

     The ATM-25's are very good. The board EQ isn't very good for kick.
     100Hz boost/cut is good for rolling off the low end to make vocals
     more intelligible, and defining the bass guitar to distinguish it
     from the kick. (A compressor inserted on the bass guitar channel
     will work wonders)

      >I got a suggestion to add a 15 or 31 band EQ as an insert on the 
    >kick. Does this sound like the best first shot or ... ???
    
     Good suggestion, but not the best first shot at the problem. You really
     gotta fix the power problem first. A 2x15 inserted on the kicks will
     help boost the 50-60Hz low-end fat on the kicks that the mixer EQ can't. 
     But, the EQ add alone will only make the problem worse.

     Here is an approximation of a 2/3 octave 15 band EQ on a kick drum.
     Fat boosted, boom removed, snap boosted, but not this dramatic. Tweak
     the mixer EQ if you need to.

          . .
        .     .       	     . . 
   0- .        .          .      . .
     	        .      .
     	          . .

     Hope this helps
     Neal

      Thanx Neal, sounds like real "sound" :) advice, and at the right
    price, too!
    
    Rog

Hey Neal - 

If you had a tri-amped stereo rig with 4 PV 118subs, (2) Renkus Heinz 15"
mids and (2) Renkus Heinz horns, which power amps would you hook up to 
who ??  Don't forget the two monitor amps we'll need after...  :)

Actual Spec's (Stereo into 4 ohms w/both channels driven):

400 + 400 =  800 - Crown PSA-2
600 + 600 = 1200 - Carver PM 1.5
600 + 600 = 1200 - Carver PM 1.5
350 + 350 =  700 - Crown Micro 1000
300 + 300 =  600 - SoundTech PL600
240 + 240 =  480 - BiAmp TL240
160 + 160 =  320 - Ashley
---------   ----
2650+2650 = 5300 - Total

How about:

(2) 118's 	       <-----Carver Pm 1.5 (Bridged - 1200wt/4 ohm)
(2) 118's 	       <-----Carver Pm 1.5 (Bridged - 1200wt/4 ohm)
(2)  15" mid 	       <-----Crown PSA-2 (Stereo)
(2)   1" horn          <-----Crown Micro1000 (Stereo)
(1) 15x1 monitor       <-----Ashley (Bridged)
(2) CV V29's (side fl) <-----SoundTech (bridged)
(2) Mitchell-Wedge     <-----BiAmp (bridged)

I'm no expert, but it seems to me that THIS config would mutilate ANYTHING
within 1 mile of the mains, plus deafen the performers (heh-heh, especially 
Guido) with monitor.  (*Some* guys can NEVER get enough monitor, I for one,
don't complain too much :) - Besides, seems like 1500wts for monitors would
be BLAZIN'.

Whatcha think ??  What do YOU think Rog ??

    Oh, now I see.  When I said that the SVT's were a good idea, I was
    under the impression that you were just putting bass guitar and bass
    drum through it. Perhaps I read your initial note wrong.  
    
    If this is part of a total PA package, then SVT's would probably not be
    appropriate.
                                   

    A repair guy once told me that *all* of the Carver amps he saw in for
    repair were used for low-end, never for mids of highs.
    
    He thought that the Carver design might limit its durability for
    low-end use.
    
    Kevin
    

    ...and Carvers don't have REAL transformers either to push that bottom
    out.
    
    Get a few Crown Macrotechs or Boulders.  They'll do the job of all the
    rest.
    
    Mike

     Hi Coop,
     Got yer mail.

     I'd use the summed lo out regardless, but it wouldn't solve the problem
     you have.

     Yeah, the amp is being driven too hard, regardless of the load, which
     in your case is 4 ohms/ch. It would make the problem worse by using only
     one pair. Four cabs will move more air than two, and the Crown working
     at 4 ohms/ch is closer to optimum than at 8 ohms/ch. Time to get the big
     amp. If you have access to a Carver PM 1.5, try it out. I betch it does
     the job.
     	BTW, I use two PM 1.5s. I used to run the whole system with three,
     and I never had problem with them that didn't turn out to be operator
     error. You can get them used around here for ~$600. They're
     450W @8 ohms/ch, and 600W @4 ohms/ch, but doesn't do 2 ohm loads. The
     new name for the PM 1.5 is the PM 1200. The PM 1250 was formerly the
     PM 2.0 which is the MosFet version, good for 625W @4 ohms/ch, and weighs
     only 11 lbs. The PM 1.5/PM 1200 weighs only 21 lbs.

     What's the PSA2 weigh Coop? |^0 

     Neal

>Hey Neal - 

>If you had a tri-amped stereo rig with 4 PV 118subs, (2) Renkus Heinz 15"
>mids and (2) Renkus Heinz horns, which power amps would you hook up to 
>who ??  Don't forget the two monitor amps we'll need after...  :)

     Uh Coop,
     You don't acually HAVE all these amps do you??!!??!?
     My head is spinning thinking about it.

     I gotta know...what are your crossover points?

     No need to bridge any amps, you don't gain anything by it, and it
     can uck fay up the damping factor of your amps. Believe me, it's audible.
     ESPECIALLY if you got the load trying to pull all that current down one
     crummy 16ga wire. There are damn few amps that can be bridged with no
     deterioration of damping factor. I can count 'em on one hand. Bridging is
     ok if you're doing a PA install in a mall or a bank or something. It's
     a real issue in your application.
     I think that one Carver would do the subs, two to a side. But if you want
     to be able to communicate with African elephants......FROM COLORADO.......
     then just dedicate each channel of the two PM 1.5s to one sub. The cross-
     over should be able to drive all four channels well, (each ch has 1.5V
     input sensitivity) especially if you use the Summed Mono Low output.
     Patching the inputs on the Carver isn't a problem. 

     The PSA2 is excellent in the Mid Bass role and the Ashley is exc for the
     horns. The MicroTech 1000 unbridged, 2 mons/side, and the same with
     the SoundTech and BiAmp. I hope yer using earplugs. 

     You be crazy Coop %^)
     Neal

>     Uh Coop,
>     You don't acually HAVE all these amps do you??!!??!?

Well - they belong to Rog ('cept for the ST and BiAmp, which we us for a
two-way rehearsal system.  He's got some major wattage - thats why I'm so 
bummed that we can't blow the roof off of the clubs we play.

>     I gotta know...what are your crossover points?

Beats the snot outta me.  I'd say the lows are crossed at about 450 cycles...
But I don't know about the mid/high point.  Where do you think we SHOULD 
be crossing them over at ??

>     then just dedicate each channel of the two PM 1.5s to one sub. The cross-
>     over should be able to drive all four channels well, (each ch has 1.5V

I'm confused - with like a 4-way "Y" cord or something ??

>     You be crazy Coop %^)

Not me, man - I'm behind the mains.  :)

Seriously though - This *is* the problem - in a 12x16 room last night, we 
had the Carver PM1.5 in bridge mode driving (1)118 bin, the Crown Micro
driving (1) 15" mid, and the Ashley driving (1) horn...  A cassette deck 
plugged into the Xover (an Ashley 3way mono) and had it on full blast.
It should've blown the roof off the place.

It wasn't that loud!!!  This what we're trying to figure out - WTF ?
My little home JVC 35wpc receiver is louder.

I got a major chubby when I saw *all* these amps...Thinking of all the 
headroom, but last night we were close to clipped the Carver that was
driving the bass-bins...

What can be goin' on here ??

Oh - I should say that we had the mid/high level on the Xover pulled
back to match the bassbin volume - the mids/highs seem plenty loud...
Are Peavy speakers THAT inefficient ??

Also - we use a 3-way *stereo* Xover - a DOD (Audiologic) X324 and "Monster"
cables with bananna clips...All mixed by a Peavy (mumble)24x4x4x2.  A very 
NICE system...

jc

    Does the Xover have level adjustments for each section ?  Might need to
    bump those UP ...
    
    Jerry

RE: Scary-mon

Yes - it does.  The bass level was CRANKED.
This is a strange one - and we're playin' *next* weekend.
I'm getting nervous.  :)

jc

    
    
    
    
                  You have the lows crossed over at 450hz?? into 18s??
                  I'll bet at 450hz the response is down at least down -3db
    
    		  You'd probably do better at about 250... mids to 2-3k and
                  horns the rest.  As was mentioned, a lot of the "punch you
    		  in the chest" does come from the low mids and the high
                  end too.  You need the snap on the kick to give the sound
    		  some definition and direction.
    
    		  Gee...it seems that 500 watts into a bunch of 18s would
    		  knock you back a couple o' feet.  And you have what?
    
    		  1200+ ???     Those speakers must be real pigs
                                (inefficient) or you have some major
    				wiring and/or crossover probs.. good luck
    

    Hi again,
    
      The low/mid crossover point is 150Hz. The mid/hi crossover point is
    at about 1300Hz.
    
      The system was not totally set up last night. We were just
    experimenting. We at best were only hooked up to 1-18, 1-15, and
    1-horn. We were using a low-fi cassette into a mono 3-way crossover
    as input to the amps.
    
    Rog

Yeah man - something is definately wrong in dodge city...
I hope we can square it away.

>Title:  Muss be a rilly big shoe....

Nha, not really... It's just that metal heads like it loud.
In this genre, 5-6K watts of PA is a drop in the bucket...

One band came in from Dallas about 6 months ago and the bums
had like 14 (count 'em) really BIG 1Kwt+ Ramsas.  When they
opened I was literally blown away.  Good band though. :)
This is the same band where the guit-player had (12) 4x12's.
Humana,humana.

So - 250cycles for the low/mid, and 2-3K for the mid/high point ??
With all the PM1.5's that'd be 600watts into each 18.  It should
HURT people.  I'm hopin'.  :)

BTW - I don't know how efficient these speakers are, but they are
black widow loaded Peavy 118subs...

jc

Yeah - like Rog said - we haven't given up all hope...
:)

jc

    
    
    Looks like you're feeding pro gear - that wants something like a +4 db
    line level in, with consumer gear, that delivers something like a -10
    db output.  Could this be the case?
    
    It would sure explain your ability to hear today...
    
    

    This might be OTL but are all the sub bins phased correctly?? If not
    they'd be working against each other ( for non techies that + to +,
    - to -)..
    
    
    (Just thinking about that much power in the low end makes my ribs hurt)
    
    FJE

I think everything is in-phase...  We'd be able to see phase problems
also, and the Xover has phase inversion.  It may be just a impedence mismatch
or something equally silly that we haven't stumbled across.

The biggest problem is one of time - ergo, so far, we've always been rushing 
to start a gig... get the system up and play  this week e've had an opportunity
step back, set it up in our own environment and diddle with knobs and
wires.  I think we'll get it all squared away though.

Keep the ideas comin' !!

jc

    Would it be possible to check the signal amplitude along the signal
    path?  
    
    Perhaps you could use the VU meters on a tape deck or another
    board that has meters: Insert a test signal into your board (test tone,
    CD w/music, tape w/music, ...).  Monitor the board output level on your
    'homebrew amplitudec checker'.  Connect up the next piece of gear in
    the chain ( graphic EQ? ) and dial in the normal gain settings. 
    Monitor the output level from the EQ, using the same test tone or same
    passage of music.  Repeat adding signal processors and checking the
    output of each until you reach the power amp.
    
    I try to run signal processors at unity gain, which would be a decent
    place to start.

      
       I've been on vacation, but after reading these replies I'll enter
    some info that agrees with some things already said.
    
       POWER AMPS: As mentioned, get the Carvers out of the low-end. They
    are fine and very useful as mid/high fronts or monitors. You need those
    big-a$$ capacitors in the power supply of a heavy duty power amp to
    keep the juice on hand for low-end power. I use a Carvin FET900 bridged
    driving twin ELITE 18" cabs (RCF 600 watt speakers). 
    
       Crossover - I'm using a system with the twin 18's on the bottom and
    the mid/high cabs have 2X10's and a horn each (also rated at 600watts).
    I crossover at 250 to 300 hz. 
    
       EQ - The bottom is down in the 18's, but a 2K EQ job on the kick
    channel adds punch. 
    
       Compression - I use an Alesis 3630 to keep the bass drum solid.
    It takes some experimentation with the compressor, make sure you don't
    overload the input - it's easy to do with a kick drum.
    
      
       Oh Yeah - Im my system the 18's can shake a room! I have a 
    Carver PM 1.5 and it does a good job of powering the mid/high cabs.
    
    							-B()()M-

     So Coop/Roger,

     Didja get it all straightened out for gig last weekend?

     How'd it go....or shouldn't I ask?

     Neal

    Actually, it's working out GREAT !!!
    
    Roger can correct me if I'm wrong, but here is how we are hooked up
    now:
    
    PM1.5 (bridged)          --> (1) Bass Bin
    PM1.5 (bridged)          --> (1) Bass Bin
    Crown PSA-2 (bridged)    --> (2) Bass Bins
    Crown MicroTech 1000     --> Mids (stereo)
    Ashley	             --> Horns (stereo)
    
    Thump, thump !!
    
    We also borrowed a spectrum analyzer with pink noise generator to set
    up the EQ.  Quite the difference...And we broke records at the club
    last night with booze sales !!  The place was jammin' !!
    
    jc