Options
How to set up my new PA?
prodjsolutions
Posts: 7
I have just ordered the dbx driverack pa and was wondering if anyone has any pointers on how to set it up for the following system?
(2)JBL TR125's
Powered by a Mackie 1400i
(2)JBL JRX118s Subs
Powered by a QSC RMX 1450
(I could switch the amps if it helps any)
I was also wondering if the PA has a crossover on it too(I am almost positive it does, but not all advertisments for it says something about a crossover)?
any help would be great thanks,
Eric
(2)JBL TR125's
Powered by a Mackie 1400i
(2)JBL JRX118s Subs
Powered by a QSC RMX 1450
(I could switch the amps if it helps any)
I was also wondering if the PA has a crossover on it too(I am almost positive it does, but not all advertisments for it says something about a crossover)?
any help would be great thanks,
Eric
0
Comments
Get us the following info, so we don't have to look it up.
Speaker specs, including Freq range (+/- 3 db) and the -10db freq
Rated \"program power\"
Cabinet impedence
Recommended x-over point if available
Amp specs
whether you are going stereo or mono on either cab and if you plan to bridge any amps let us know.
Dra
Here are the specs:
JBL TR125
Front loaded 2-way loudspeaker
Frequency Range: 55 Hz - 16 kHz (-10 dB from rated sensitivity)
Power Capacity 225 Watts (Continuous Pink Noise EIA RS426A, 8 hrs)
Peak Pink Noise: 900 Watts
Nominal Impedance: 8 Ohms
Sensitivity: 99 dB (1W, 1m)
Nominal Dispersion: 90° Horizontal x 45° Vertical
LF Driver: 1 x 380 mm (15 in)
HF Driver: Pure Titanium Diaphragm Compression Driver. liquid cooled
Horn: Optimized Apertureâ„¢
JBL JRX118
18� Subwoofer
Frequency Range (-10 dB): 38 Hz - 300 Hz
Frequency Response (±3 dB): 55 Hz - 300 Hz
Sensitivity : 101 dB SPL
Nominal Impedence: 4 ohms
*Power Capacity: 350 watts
*Peak Power Capacity: 1400 watts
Recommended Amplifier Power: 350 watts to 700 watts into 4 ohms
Recommended Crossover Settings: 30 Hz HPF, 24 dB / octave; 80 - 100 Hz LPF, 24 dB / octave
Maximum SPL: 127 dB
Mackie 1400i
Power Amplifier
1400 watts @ 4 ohms bridged
1000 watts @ 8 ohms bridged
700 + 700 watts @ 2 ohms stereo
500 + 500 watts @ 4 ohms stereo
300 + 300 watts @ 8 ohms stereo
Ultra-low-noise/ low-distortion design
Fast Recovery circuitry reduces distortion at the edge of clipping and beyond
Two 2nd order, 12dB/octave, Bessel low-cut filters with variable frequency from Off to 170Hz help optimize bass output of your sound system
3rd order, 18dB/octave, Bessel electronic subwoofer crossover with two selectable frequency points
Constant directivity horn EQ/Air EQ with variable frequency from 2k to 6kHz and on/off switch
Limiter with On/Off switch (decreases distortion that may become present when the M•1400/1400i is driven at max levels without affecting overall sound levels)
XLR thru outputs
QSC RMX 1450
Power Amplifier
1400 watts @ 4 ohms bridged
900 watts @ 8 ohms bridged
700 + 700 watts @ 2 ohms stereo
450 +450 watts @ 4ohms stereo
280 + 280 watts @ 8 ohms stereo
Signal to Noise (20 Hz–20 kHz) 8 ohms: <-100db
Frequency Response: 20 Hz–20 kHz: + 0/-1 dB, -3 dB points: 5 Hz–50 kHz, LF filter bypassed, 8 ohms
I hope these are the specs you were looking for.
thanks in advance
Kevin
Any components that are not listed in the wizard should be \"custom\".
Set up EQ as dual mono (still stereo, just controlled together)
X-over -
Hi - 100hz BW 24
Lo- 50hz BW12 100hz BW24
50hz because you are under powered. You can't bridge your subs because each cab is 4 ohms and the amp is listed as going 2 ohms in bridge mode. So you'll have to make do.
You can also play with the 100hz setting as well.
Do the gain structure per the back of the manual.
Set the limiters per the back of the manual.
Balance the system volume with the x-over gains or reducing (only) the amp knob (attenuator) of the louder component.
Do this, report back and we'll tackle other issues. (I hope you have the RTA mic).
Dra
Sorry,...my bad...:oops:
prodjsolutions,...I know the following suggestion is probably a budget-buster: I would consider bridging the QSC1450 at 4 ohms for one sub channel and picking-up another 1450 for the same on the other channel...
Kevin
Sorry
Dra
OK Dra,
Let me have it! What do you think?...
450w per sub (450w + 450w = 900w into 2 subs)
1400w into 1 sub
Using the Crown rec of 875w as nominal...
1 is on the low side and 1 is on the high side.
Also consider, the tops are rated at 450w program.
The amp it rated at 300w @ 8 ohm.
I bet Gadget knows the formula for figuring db output comparing the 2 sub scenarios. I think however, that in the end it ain't gonna matter cuz he's gonna be limited by the tops any way. If all things are equal, then I would probably make 2 subs work let hard rather than 1 work extra hard. I assume that amps will not be clipping in either case.
Gadget? I yield the floor to the gentleman from Wisconsin.
Thoughts?
Dra
http://www.csgnetwork.com/decibeloutputcalc.html
Axisplayer, that is a cool calculator.
Dra
Hey Dra,
It just occured to me that: here we are beating our heads, discussing this stuff, and that prodjsolutions may never return to reply... Oh well...at least we got a cool calculator!...:)
Kevin
G
Dra
http://www.sengpielaudio.com/Calculations03.htm
I lived at this site for a while until I got a grip on things.
Thanks
Excellent site!... Hey,...based on your username: What is your axe of choice in regards to electric and acoustic?...
Kevin
Too bad I just spent about $2,200 on new DJ equipment, now I will need to save up for new amps! I will let you know how it goes when I get the new equipment should be about a week!
If you decide to power-up you may want to check-out the Behringer EP2500 amplifier... It's basically a QSC MRX2450 clone (or EP1500 for MRX1450) and sells for anywhere from $278.00 to $349.00... You can click here to read several reviews on the EP series... I believe the trick to this amplifier is wiring and configuring it correctly from the start!... I put nine of these into service in our church's youth center and I'm extremely satisfied with their performance... I will have to say this: they are heavy (37lbs)...but wasn't a factor for me...:)
Kevin
Are you using the onboard clip limiter?
How are they doing on sub duty? The 300> damping spec is kind of low (same as QSC though). For comparison...
Crown CE-2000 400>
Yorkville AP3000 500>
Crown MT2400 1000>
Crown Belchfire 1,000,000,000>
Dra
After reading numerous reviews on those amps it occurred to me that some of the "negative reviews" could be a result of incorrect wiring and/or usage... I have to decipher the expertise, knowledge level, and objective of the reviewer whenever I read their comments,...and particularly so from web sites like MusiciansFriend... For example: If I read a review that goes like this "These speakers are no good they blew after two gigs! I could see the coils glowing cherry red during our last performance!"... What's the reviewer telling me?... Is that the speakers are no good,...or is that the reviewer has no clue about what they're doing?...:oops:
Here's another example: "I own both the QSC RMX???? and the Behringer EP???? and QSC blows Behringer away!"... Is it that QSC blows Behringer away,...or is it possible that the reviewer's employed by QSC?...:shock:
I have to consider every scenario when there are several "conflicting reviews" about the same item...
Hey,...The amps are doing great for sub duty!... Now with that being said; are you considering that I'm a newbie at this PA stuff?...:)
Ya'll...I gotta get me one of them-there Belchfires!...
Have a nice weekend Dra...
Kevin
PS. Yes,...using the clip limiters...
Fact...the BEH 2450 has a stiffer power supply than the RMX... bigger caps and heftier wiring... I have the NADY versions of these amps... made in the same factory..just using different cases. I have had a couple failures.. on theses amps...collectivly we have 10. I had one fail on burnin, and was replaced at no charge..they even sent for the amp for replacement (I didn't have to ship it back). I also have an RMX 2450 and 4050. not very impressive next to my Mac 3600 and 2400.. but usable. Cory has one in service (repair)right now....power supply failure I think. I hate to mention this (sorry Kevin) but I think if your going to buy amps I'd consider stepping up a bit..I know I won't buy any more of the conventional power supply amps period!
My top choice is Digam/Powersoft, but they are spendy...
Mikey swears by the Crown Xti series with built in DSP and hi Q net.. and at about $750 @ NSL are a great amp choice for bigger power (a 34.2 db gain or in excess of 3200 watts @ 4 ohms) and are lighter @ only 10 lbs much better for portable use.
Yamaha also makes the P5000 and P7000 amps that are 4 something and about $550 for the 7000 and are about 24 lbs.
These amps I have listed have a huge advantage that is more important than even the weight.. that is power consumption... they are far more efficient than the conventional power supply amps. They draw less power, run cooler, and are far less picky about what kind of power you feed them...and God knows those of us that operate in the real world usually end up trying to squeeze 10,000 watts from a 15 amp circute on a 100 foot 14 gage value-mart extension cord.. and sharing 1/2 of a duplex with the lampies (Sound tech slang for lighting guys...) To give you an idea of what I'm talking about last year we ran 6 LABsubs (3.2 ohms each) off a single Digam 5000 using a 100 foot 14 guage cable...out in a field. There was a sound production company there also with 8 JBL 4719's with each pair powered by a Mac 5000 which draws 30-35 amps EACH... thats a whopping 130 amps for the subs alone! The system provider came over and asked that we turn the system down because his system COULDN'T EVEN BE HEARD! and he was PISSED!... then when he asked what we were using... and we said that 1 rack space blue 17 lb amp... the Digam..(now we also had 6 of the Nady 2450's powering the 6 PAS RS 1.2 speakers in fullrange mode...but ...) \"oh sure you are.. your using those OTHER 6 amps..\" to which we said ..\"If you'll follow the wires from the subs you can clearly see that they are going to the Blue amp\" then he was REALLY pissed.. he went and got every sub in his warehouse and still couldn't be heard...To prove a point.. while he was gone, My son hooked that same amp up via the 100 foot 14 gage cable and the subs still CRUSHED his system...Now I've never been a fan of JBL speakers.. ESPECIALLY the 4719's.. but when powered properly they can get up and bark.. but this proved beyond a shadow of a doubt that
A.. Labsubs RULE!
and
B.. The Digam/Powersoft amps are insanely powerful...you do the math guys.. 3 each 3.2 ohm speakers on each channel paralleled...... outdoors...all day! and the final debasement... run on a 100 foot 14 gage cable...THAT gentlemen is efficiency! That is why I will not buy conventional amps...oh that and my son is developing a new series of amps that will have all the atributes of the Digam amps and plug and play power supplies.. which means...plug it in and it just works...120v single phase...230v, 120 v balanced.. whatever.. it just works, even low voltage situations won't deter these amps. They are also going to be variable output...dial in how much power you want. Well there it is...
My $1.20 worth
Gadget
Dra
I'd spend the xtra $150 and call NSL and get the XTI4000.. Crown rates conservatively... plus you get the DSP.
G
I really hope to do another decent size system (with a decent budget) sometime soon so I can try some high-end speakers and more efficient amplifiers...
Believe it or not I got a phone call yesterday from a guy that wants me to look at putting a sound system in his wife's salon... I'm supposed to meet with them this Monday... I know it will be a ceiling speaker type set-up and have already started thinking about the numerous possibilities...
Hey,...has anyone used the Rolls rack mount equipment?... It appears to be very flexible for this type of system... They have a 1-slot FM tuner/CD player, 1-slot stereo mixer, and a variety of 1-slot amps (25 volt, 70volt, 4-16 ohms)... Also,…does anyone know of a rack mount Sirius (satellite radio) receiver?...
Kevin
Never mind,...I found it: SRH550 tuner with SRH550BK brackets...
Kevin
But,...the XTi has the DSP (crossovers, etc., etc.,) built in...so that would be a little redundant if you have already purchased the DRPA...
Decisions...decisions...decisions... You gotta love it!... For me that's the fun part...matching it all up for the $$$$... IMHO the system is only as good as the crappiest piece!... That comes from the embeded thought process of an "old school audiophile"...:)
Kevin
All the other tuners can be rack mounted as well. Get a roll of double sided carpet tap. Whala'
Don't know if the law has changed in the last couple of years, but any permanently installed system (in a business) that plays music or the radio is subject to ABSCAB, WHOMBAT, OSHKOSH, FEMA, whatever fees. Heard that on Paul Harvey. But I'd keep that to myself and let them deal with that.
Dra
Yep,...this is probably going to be a low budget system... I'll make some suggestions, install whatever they decide on, make sure it's done right,…and be done with it....:)
Like you say Dra... As far as what they play on it or use it for is their business...