T.R | Title | User | Personal Name | Date | Lines |
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891.1 | there are differances | ANT::SDRP_JACQUES | | Thu Oct 06 1988 08:58 | 16 |
|
There are differences. The obvious differance is that stereo EQ's
have RCA phono inputs and outputs. Pro gear generally has both
1/4" phone jacks and balanced XLR jacks, although some of the
pro gear designed for recording use do have RCA phono jacks. Pro
units are designed to operate at 1v line levels, and have balanced
transmition lines. Balanced outputs are very important on a pro
unit so you can drive the signal from the sound board back to the
stage where the power amps are located. Stereo gear is meant to
operate at lower voltages than 1v line level, therefore you could
end up overdriving the inputs of a stereo EQ. I would say, if you
are doing some home recording on a Multi-tracker, a home stereo
EQ would be usable, however for PA use it would not do as good a
job.
Mark
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891.2 | re.1 Can you answer a couple for me? | VOLKS::RYEN | Rick Ryen 285-6248 | Thu Oct 06 1988 11:49 | 25 |
| re: < Note 891.1 by ANT::SDRP_JACQUES >
Mark,
You sound knowledgable. Can you answer a few questions for me?
>>>"Pro gear generally has both
1/4" phone jacks and balanced XLR jacks..."
Could you briefly explain to the terms balanced outputs
and balanced transmission lines? Can I assume that anything
that has a 2 conductor XLR connector is balanced?
Can I assume that 1/4" is unbalanced? How do I decide when
to use one over another?
>>>"Balanced outputs are very important on a pro
unit so you can drive the signal from the sound board back to the
stage where the power amps are located. "
The set-up I work with occasionally, has the power amps set up at
the board, sending the high power signal to speakers on stage
over 1/4" lines. Is it better to send the low voltage signal
on balanced lines, with the power amps on stage?
Any insite for this novice apreciated?
|
891.3 | What He Meant Was ......?? | AQUA::ROST | Canned ham, that's for me | Thu Oct 06 1988 12:17 | 37 |
|
Re: .2
1. NO you CANNOT assume anything with XLR jacks is balanced....just
ask Dan Eaton. 8^) 8^) 8^) In some XLR gear the third conductor is
grounded, which makes things unbalanced, which removes the whole
advantage of going to XLRs in the first place...balanced lines have
superior noise immunity.
2. Placement of the power amps relative to the speakers has to do with
power loss. Running high power amps it is ideal to use very large
gauge speaker cables and to keep them short. The resistance loss of a
speaker cable is roughly inversely proportional to the conductor
thickness (i.e. gauge) and proportional to the length.
If you use a cable that is twice as thick and run it only half as
far, the power lost *in the cable* will be cut by a factor of 4.
Long runs of narrow gauge cable can generate a lot of heat if high
power is applied to them....heat is the biggest thing leading to
cable breakdown (other than physical abuse). Plus it saps watts
that could be going to your speakers.
If you therefore decide to place the power amps close to the speakers
and away from the mixer, you need balanced low impedance lines between
mixer and amp unless the separation is under 20 feet (in which case
high impedance will work, but low impedance is still preferable).
As far as the EQ needing XLR outs, look at it this way...whatever
unit is directly connected to the power amps must have XLR outs.
So if the signal goes from board to EQ to amps, the EQ needs XLR
outs but the board doesn't.
If the device doesn't have XLR outs you can use transformers that
convert 14" high impedance, unbalanced to XLR low impedance, balanced.
|
891.4 | Lo/Hi/Bal/Unbal/Line/Mic | LEDS::ORSI | You live around here often? | Thu Oct 06 1988 14:12 | 22 |
| Re-.3
>and away from the mixer, you need balanced low impedance lines
>between mixer and amp unless the separation is under 20 feet
>(in which case high impedance will work, but low impedance is
>still preferable.
You are confusing low level (~100mV) lo and hi imp
signals, like a mic or guitar output, with line level (~1V)
lo imp balanced and hi imp unbalanced signals, like a mixer,
eq, delay, compressor, etc. output. Line levels lo or hi can
be driven down long lines, like the returns on a snake back
to the power amps from a mixer. But like someone said, balanced
lines will greatly improve noise immunity. I run my PA system
totally unbalanced with no problems. All my patching is done
with 1/4" to 1/4" cables.
Neal
Hi impedance mic cords and guitar cords should be kept under 20 ft
to prevent hi and lo frequency losses.
|
891.5 | Good info! | CSC32::G_HOUSE | Back in Black | Thu Oct 06 1988 14:27 | 5 |
| Thanks all, I was thinking of the EQ to use with my guitar and/or
PA, so it sounds like I'd better avoid the ones designed for home
audio use.
Greg
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891.6 | My bug might be EQ | VOLKS::RYEN | Rick Ryen 285-6248 | Thu Oct 06 1988 15:05 | 27 |
| Yeah, thanks from me also. I'll have to check out
the actual PA set-up to see, but I think we may have
things that break some of the rules that you have discussed.
As I recall, our EQ has only RCA plugs. The setup is owned
by a keyboard player, so I suspect that he got the EQ
FOR keyboards, and just started using it on the full PA.
From what I've seen keyboard stuff seems to
have lots of RCA plugs, so it probably works fine for a
keyboard only set-up.
You wouldn't believe how extensive this PA is, yet it
still doesn't sound right. There is a fly in the ointment
somewhere, and it seems to be AFTER the mixing board somewhere.
I suspect the EQ or cable-ing.
Some pro's have run the board a few times, and they seem to
magically get it tweeked up just fine. Seems like when anyone else
(including myself) touches it, it goes downhill quick.
It never makes a clean transition from one set-up to
another without lots of bugs.
Maybe I'll start a new note on the subject of PA set-ups
and such. I could use a few tips.
Rick
|
891.7 | more thoughts | ANT::JACQUES | | Fri Oct 07 1988 09:57 | 54 |
|
For anyone interested, Peavey has a nice write-up about
low impedance vs high impedance, balanced vs unbalanced,
line level vs mic level, etc. in their pro equipment
catalogue. It was written by Jack Sondermeyer. Any Peavey
dealer should have catalogues with this article in them.
I guess I need to correct what I said in .1, Stereo equipment
does run on 1v line levels (Thanks for the info, Niel).
I find the home recording equipment is where the differant
standards all come together, as home recording gear often
includes 1/4", RCA phono, and even XLR inputs on some models.
I get around this by using adaptor cables rather than using
adaptors between 2 cables. You can buy cables from Hoya,
Peavey, Whirlwind, etc. that feature 1/4" on one end, and
RCA phono on the other, or any other configuration you need.
You can also use transformers to go from a balanced line into
a 1/4" input on a recorder, mixer, etc. when they don't have
balanced inputs.
I ran into a situation a while back that made me wonder. A guy
showed up at a jam and wanted to plug his keyboard into the PA
via the 1/4" line out jack on his amp. He didn't have a long enough
cable, so I tried to use a mic cable with a transformer on the end,
no-can-do. The transformer is only meant to work one way with
the input going to the primary, and the output taken from the
secondary. The XLR male/female scheme prevented me from connecting
things this way, fortunately. I found out that the only way to
accomplish this sort of thing is with a direct box. I am considering
getting one or two direct boxes for the next time I encounter this
problem. I suppose I should get active boxes if I am going to
get any. Anyone care to suggest a good quality, reasonably priced
active direct box I should look into? Maybe I should just buy some
long unbalanced cables for this purpose since 1v line levels can
travel across unbalanced lines without signal loss problems? What
is the max length I could run 1v line levels across unbalanced
lines without noise problems ?
Mark Jacques
Another thing about home stereo equipment to keep in mind
is that it is not road worthy. It is designed to sit in
your home entertainment center semi/permanently installed.
Even if it has rack ears on it, this does not mean that
it is pro gear. RCA phono jacks are not designed for constant
plugging and unplugging. You can buy high quality, fairly
durable RCA phono cables, but the jacks on the rear panels
of stereo equipment can only take so many insertions.
|
891.8 | more eq info needed !!! | ANT::JACQUES | | Mon Oct 10 1988 15:59 | 20 |
| While we are on the subject of Equalizers, I am considering
getting an eq for my PA system, as well as one for my guitar
effects rack.
For the PA, I sometimes run stereo, sometimes mono, but I think
I would be better off with a stereo unit. Even if I am running
mono, I could EQ the voices and instruments separately. I have
looked at EQ's from Peavey, dbx, Rane, and Yamaha. I have narrowed
the field to either getting a Rane, or a dbx. The dbx model I am
interested in has a neat feature. It can either be used as a
stereo 15 band/side eq, or a mono 31 band eq, selectable at the
flick of a switch. Is anyone familiar with this unit? What do
you think? Would I be better off witha Rane? The dbx is around
$300 to $350. How much for a good Rane eq ?
For guitar playing, how is the SRD half-rack eq's. How about the
Boss mini studio eq. Would either unit work well in an effects
loop with a distorted signal slamming into them ??
Mark
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891.9 | | MARKER::BUCKLEY | Quayle? Ahahahahahahahahahahahahahahahahaha | Mon Oct 10 1988 16:23 | 15 |
|
Peavey has a nice dual 15 band graphic for a little over $200. It has
some nice features like low cut filters, and some notch effects. Its
nice because the frequency resp. of the unit doesn't change as you
boost/cut the output level!
Ibanez has a dual 15 band, but its not as nice.
Don't like the DOD eq's...too noisy!!
The Scholtz stuff is *OK*, not as bad as some stuff. I'd get the
scholtz unit over, say the BOSS half rack 10 band graphic.
I like the stereo eq's because you always find use for an eq even
if application isn't immediately nec.
|
891.10 | Another EQ question | CSC32::G_HOUSE | Dracula Sucks | Tue Nov 01 1988 10:50 | 3 |
| What is the difference between a graphic EQ and a parametric EQ?
Greg
|
891.11 | Parametric Vs. Graphic | AQUA::ROST | You've got to stop your pleading | Tue Nov 01 1988 11:11 | 57 |
|
A graphic EQ is so-called because it usually uses sliders, so that
you get a "graphic" representation of the EQ adjustment by looking
at the slider positions. It is just a multi-band EQ with all interior
bands being of the "peaking" type....that is, the boost/cut is maximum
at the marked frequency and drops off as you move away from that
frequency in either direction. The highest and lowest bands may
also be peaking, or they may be "shelving" types, that is, moving
in one direction away from the center frequency, the boost/cut falls
off, but in the other direction it remains constant. In simple
EQ systems (like your guitar amp, bass and treble are usually shelving
type and mid usually peaking type.
Shelving:
-------- ------------
\ /
\---------- ---------/
Peaking:
/\ -------------- --------------
/ \ \ /
------------------/ \--------- \/
A parametric EQ is almost always of the peaking type. Simple
versions (sometimes called semi-parametric or quasi-parametric)
simply allow you to choose the center frequecny where the boost/cut
will occur. In true parametric systems, you can also adjust the
"Q" or slope of the boost/cut. In other words, you can have the
EQ act on a very narrow range of frequencies (good for feedback
control or eliminating "dead spots" on your guitar neck) or act
on a wider range of frequencies for more broad tone shaping. Most
parametrics have fewer bands (maybe 2 or 3) than graphics, which
may have anywhere from 5 to 31 bands.
Narrow Q:
/\
/ \
----------------/ \------------------
Wide Q:
/------\
/ \
----------------/ \------------------
|
891.12 | EQ frequency points | FRETZ::HEISER | ask me | Thu Apr 30 1992 16:21 | 5 |
| Does anyone have info on the basic cutoff frequencies in relation to
the guitar? How do you know what settings to use to achieve a
particular sound?
Mike
|
891.13 | pontification alert... | EZ2GET::STEWART | You're just supposed to sit here? | Thu Apr 30 1992 17:26 | 17 |
|
Don't have numbers for you on the first question, but I'm reasonably
sure the fundamentals are with the 100 Hz to 5 kHz.
In response to your second question - you need two precision
instruments: your ears and your brain. First, you need to listen
critically to the sound you're after (if you're trying to emulate and
existing sound). Secondly, you need to be able to hear what your EQ is
actually doing to the sound you're shaping. This means not only
shaping the frequency response curve, but being able to distinguish how
the effects affect the sound, also. I know this is incredibly
obvious...
The thing is, EQ is not sufficient to change the voice of an instrument
beyond some small degree. No amount of EQ is going to make a strat
sound like a Les Paul...
|
891.14 | | RAVEN1::JERRYWHITE | Hey you're pretty good - NOT ! | Thu May 07 1992 06:21 | 21 |
| I need some advice on stomp EQ's for guitar. I'm gonna buy one *real*
soon .... anybody got any pro's or con's about any of 'em ? What have
ya had, what did ya like, what did ya hate, how much was it, have ya
got one you'd like to sell ?
Here's what I'm gunning for. I'll be using a Laney combo on a clean
setting, an Ibanez Tube Screamer (or something similar) for nastier
stuff, and the EQ to boost clean and dirty voices during leads. A wah
will be in the chain on occasion, should "Voodoo Chile" enter the
picture.
If the EQ gets a *little* dirty when the signal is boosted, that's
fine.
Talk to me .... 8^)
ps - Hey Greg, can I buy that Wasburn back (complete with the custom
2EZ graphics on the bottom).
Jerry
|
891.15 | .02's worth | WEDOIT::KELLYJ | Think for yourself | Thu May 07 1992 07:31 | 3 |
| I haven't used a floor EQ for a while, but I did use two in the past: a
6-band MXR graphics, battery powered, and a 10-band MXR, AC powered.
Both worked okay as EQ's, but the 6-band was WAY noisy.
|
891.16 | guit - eq - amp is my signal chain | DEMING::CLARK | accept STRESS into your life | Thu May 07 1992 08:52 | 16 |
| I use a DOD 7-band EQ and I think it works fine. You can boost or
cut by up to 12dB for each channel, and boost or cut the overall
gain by 12dB. I paid about 55-60 bucks for it. Using it to boost
clean and dirty voices during leads is one of the primary uses I
have for my EQ pedal. Keep the overall volume flat, boost the
800 hz band about 6dB, the 400 and 1600 hz bands about 4dB, and
maybe the 200 and 3200 hz bands about 2dB. This will make your
guitar signal fatter and louder, but not so loud that you totally
overwhelm your non-eq sound.
The other thing you can do is use the same settings but boost the
overall volume about 3 dB and keep it on all the time. Your amp
sees a much stronger, fatter signal coming in and gives you more
total crunch per unit of music that way.
- Dave
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891.17 | Tube screamer +GE7 = Ahhhhhhhhhhh | ESBTRX::KALINOWSKI | | Thu May 07 1992 09:23 | 17 |
|
Jerry......
The best combination I've ever heard was ....
Guitar--->Boss GE7----->Tube Screamer----->Marshall
This worked perfectly for the type of setup you described. I've heard the GE7,
the Ibanez parametric, the MXR and the DOD and the Boss takes the cake for
floor stompers. (Unless TC or Lexicon makes a stomper I don't know about)
Try the GE7, I guarantee you'll love it in conjunction with the tube screamer
I use one with my Marshall.
Brian
|
891.18 | | CAVLRY::BUCK | your ghost haunts my soul | Thu May 07 1992 09:30 | 5 |
| >>Guitar--->Boss GE7----->Tube Screamer----->Marshall
Two big votes for this combo!!
|
891.19 | Thanks guys ... I see the light ! | RAVEN1::JERRYWHITE | Hey you're pretty good - NOT ! | Thu May 07 1992 09:59 | 8 |
| Sounds like a plan. From the propaganda I've been reading, the GE7
seems to be a superior unit. Kinda high though ... $89 from American
Musical Supply.
Strat ---> Boss GE7 ---> Classic Tube Screamer ---> Laney ProTube Combo
Jerry (with the VISA in his hand ... 8^)
|
891.20 | Three BIG votes... | KDX200::COOPER | Step UP to the RACK ! | Thu May 07 1992 10:35 | 7 |
| A little steep perhaps, but you get whatcha pay for...
The GE7 is a nice unit for boostin' the input gain as you
described. I bet that Laney screams with a TubeScreamer and
a GE7.
jc (Who was the original owner of that Washburn/2EZ special :)
|
891.21 | | RAVEN1::JERRYWHITE | Hey you're pretty good - NOT ! | Thu May 07 1992 10:46 | 7 |
| Yeah, I remember. I think that pedal was the first thing I ever sold
through notes.
I gotta demo a GE7 this weekend for sure.
Jerry
|
891.22 | I thought I saw one in 2.* | FRETZ::HEISER | ask me | Thu May 07 1992 10:58 | 1 |
| Wasn't someone in here selling a GE-7?
|
891.23 | | RAVEN1::JERRYWHITE | Hey you're pretty good - NOT ! | Thu May 07 1992 11:00 | 3 |
| If so, would they please stand up ! 8^)
Jerry
|
891.24 | As a service to our readers | SSDEVO::LAMBERT | Gonna boogie my scruples away | Thu May 07 1992 11:16 | 3 |
| See note 2.1923. "search" is a wonderful tool. :-)
-- Sam
|