Getting started ...PA power
dbxdbx
Posts: 12
Hi folks,
Just bought a DRPA but a power amp is in the repair shop right now, so I haven't had a chance to plug everything in yet. I wanted to get some basic sub/amp pointers before I get locked into any bad habits! I'll be using a DRPA plus the gear below for a 5 piece band that plays straight bluesy rock on the loud side in small ( 50 - 100 capacity ) clubs...
Our gear has some mileage on it for sure, but here's the manufacturers ratings...
power amps on hand ( I'm showing smaller specs when mfr provides more than one ):
QSC RMX2450
450W per channel @ 8 ohms per side
650W per channel @ 4 ohms per side
1200W per channel @ 2 ohms per side
1300W bridged into 8 ohms
2400W bridged into 4 ohms
QSC MX2000a
450W per channel @ 8 ohms per side
650W per channel @ 4 ohms per side
1000W per channel @ 2 ohms per side
1300W bridged into 8 ohms
2000W bridged into 4 ohms
top speakers on hand:
(2) JBL EON 1500 ( 8 ohms each )
\"average\" power handling = 220W
\"peak\" power handling = 900W
sub speakers on hand:
(2) YAMAHA SW215 subs ( 4 ohms each )
\"program\" power handling = 1000W
\"max\" power handling = 2000W
Questions:
1) what configration of amps/speakers makes the most sense with the given gear and DRPA? Do I need more power?
2) one possible configuration is stereo tops and stereo subs, but I'm concerned the subs would be underpowered. To avoid this, alternate configurations would be:
a) get rid of one sub, use the single remaining SW215 sub and bridge the sub amp into 4 ohms...this would be a \"mono sub in the middle\" setup
or....
b) get rid of *both* 4 ohm subs, buy a pair of 8 ohm subs and bridge the sub amp into 4 ohms...this would be a \"subs on each side\" setup.
Any thoughts on pros or cons of a) vs. b) given the gear available?
3) the power amps are almost equivalent ...should I have a preference about which one is used for subs and which one is used for tops?
4) any general ideas or gotchas I should be aware of in using my DRPA with the gear on hand?
Thanks so much for your insight!
Just bought a DRPA but a power amp is in the repair shop right now, so I haven't had a chance to plug everything in yet. I wanted to get some basic sub/amp pointers before I get locked into any bad habits! I'll be using a DRPA plus the gear below for a 5 piece band that plays straight bluesy rock on the loud side in small ( 50 - 100 capacity ) clubs...
Our gear has some mileage on it for sure, but here's the manufacturers ratings...
power amps on hand ( I'm showing smaller specs when mfr provides more than one ):
QSC RMX2450
450W per channel @ 8 ohms per side
650W per channel @ 4 ohms per side
1200W per channel @ 2 ohms per side
1300W bridged into 8 ohms
2400W bridged into 4 ohms
QSC MX2000a
450W per channel @ 8 ohms per side
650W per channel @ 4 ohms per side
1000W per channel @ 2 ohms per side
1300W bridged into 8 ohms
2000W bridged into 4 ohms
top speakers on hand:
(2) JBL EON 1500 ( 8 ohms each )
\"average\" power handling = 220W
\"peak\" power handling = 900W
sub speakers on hand:
(2) YAMAHA SW215 subs ( 4 ohms each )
\"program\" power handling = 1000W
\"max\" power handling = 2000W
Questions:
1) what configration of amps/speakers makes the most sense with the given gear and DRPA? Do I need more power?
2) one possible configuration is stereo tops and stereo subs, but I'm concerned the subs would be underpowered. To avoid this, alternate configurations would be:
a) get rid of one sub, use the single remaining SW215 sub and bridge the sub amp into 4 ohms...this would be a \"mono sub in the middle\" setup
or....
b) get rid of *both* 4 ohm subs, buy a pair of 8 ohm subs and bridge the sub amp into 4 ohms...this would be a \"subs on each side\" setup.
Any thoughts on pros or cons of a) vs. b) given the gear available?
3) the power amps are almost equivalent ...should I have a preference about which one is used for subs and which one is used for tops?
4) any general ideas or gotchas I should be aware of in using my DRPA with the gear on hand?
Thanks so much for your insight!
0
Comments
Read the Welcome FAQ it may answer your questions..
what would you get for subs in place of the Yamaha's? because 650 watts isn't gonna get you the loudness you want.. safely...
The RMX has a better power supply... so I'd use that for sub duty..
Gadget
Assuming you were referring to the subs - am I underpowered even in the 2a) and 2b) scenarios? I thought bridging the RMX2450 into capable subs ( whether a single SW215 or a couple yet-to-be-determined 8 ohm boxes ) would fit the bill alright...(?)
On the possible replacement subs for the SW215s at 8 ohms instead of 4...I'm not that far along yet - I'm open to suggestions while in the typical spot of being on a budget, yet concerned about avoiding crap.
1) I noticed a couple of JBL 418S boxes for sale in town, but I believe they are 4 ohms as well, so I'd be back to the 2a) scenario of a single 4 ohm sub...which might be OK.
2) I live near a lesser-known manufacturer ( Madison in Colorado ) that has a continual presence on ebay ...they have some 8 ohm subs with 200oz magnets that appeal to the bargain-hound in me
3) < Insert your ideas about other possible good values in 8 ohm subs here ! >
Any general pro/con thoughts about a single middle sub vs one on each side?
Thanks for your expertise, forum dudes...!
Buy another amp (I know that was not an option) and bridge each to a sub box. That's 2400w / cab, 1200w /speaker.
Don't play so loud.
DRA
Yes you could bridge 1 sub only...
cab you do any woodworking>
G
G - juju is a technical audio term I hadn't heard before LOL! Translation could only be one of a few things - subpar drivers, subpar design, subpar construction... or all of the above?
yeah woodworking is great ...used to build my own guitar cabs in high school ( cough ) thirty years ago ( cough, cough ). I saw some threads here referring to sub plans available if that's what you're getting at. With a sweet and efficient design, plus a couple of of killer raw 8 ohm drivers ( recommendations welcome!), I'd enjoy being Mr. Sub Shop and building the pair I'm looking for. I bumped into this informative link the other day ( http://colomar.com/Shavano/subs.html ), but it refers to inexpensive cab design software rather than including specific plans..
Didn't mean for this to become a DIY sub thread, but it's an attractive option...
Thanks again G & Dra!
Gadget
As of right now, it looks like I'll use a single SW215 while investigating the \"build\" option...
Audiophiles have long known that smaller drivers make better sub woofers... they move faster and the cone is lighter and less mass requires less power to motivate
Like a Ferrari engine in engine in a dump truck!
G
I thought it was that the smaller cone could withstand the higher stresses/pressures involved with horn loading.......
The thing is with the same motor structure as an 18\" speaker a 10, or 12\" would be like a dump truck with a Ferrari motor (the 18\") and a Ferrari with a Ferrari motor...( the 10\" / 12\") which one will start and stop faster? Which will be affected the least by the loading of the air mass it must push? If the speaker is capable of reproducing the frequencies and the cabinet is well designed.. the smaller driver will go lower.. be louder and have less distortion.
About the only thing the 18\" has over the smaller drivers is the amount of air moved with each stroke, but with the ability to get more strokes in and in the case of the LAB 12 and 10\" Eminence drivers they have a huge stroke comparatively.. 13mm versus 4.5mm with the 18\"...thats nearly 3 times the excursion...
G