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[Dave Dermont]

My school dance rig for DJs is 4 Yorkville E15 tops over 4 Yorkville LS808 subs.  I'm running 4 Crown XLS802 amplifiers to power it, and using the recommended Yorkville EP1215 processor for any crossover/EQing that is necessary.  The processor was recommended by both Yorkville and my dealer.  For my larger events I bridge the sub amps and run each bridged mono at 4 ohms...smaller events I just run the amps in stereo.

I typically run the tops in pairs off to each side of the stage sitting up on small scaffolding or moving head road cases, splayed slightly to help eliminate any comb filtering issues.  I usually run the subs center clustered on the floor directly in front of the stage.  The stages are usually anywhere from 18"-30" in height and sit 8-16 feet off the back wall.  As far as the center cluster goes - I just sit them all side by side - I don't stack any of them or lay any on their sides since Yorkville told me there shouldn't be any real noticeable difference.

I think I should be getting significantly more output from subs than I am - I don't know if its something I am doing wrong in setting my gains or if that processor isn't as good for the system as say a Driverack or similar processor would be.  The bass seems to fall off very quickly as you move away from the subs - you can hear it, but you don't feel it.  I was always under the impression this quasi-horn loaded design should allow the bass to carry further than a typical bass reflex (I could be wrong in that assumption - I'm not an expert at all).  I am not a sound pro by an means - I rarely ever provide sound for anything other than DJs and the occasional small wedding band/musician. 

I have wondered for a quite a while if I need to ditch the Crown XLS802s for QSC RMX2450s or 1850HDs?  I get conflicting information from Yorkville and Yorkville dealers so I have just left everything well enough alone for the time being.  At this point I either need to figure out how to get the most output possible from these subs, or sell the system and move into something else.

The info about checking the speaker cable is good. I'd do that first.

Also, when bridging the amps, make sure you are using the two red "banana" outputs, not the Speakon outputs.

If you are using the Speakon outputs, we have found the problem.

The amps you are using supply just enough power for the 808s, with nothing left over for headroom.

Moving to a slightly higher powered amp by a different manufacturer would be a waste of money.

For those keeping score, the difference between the 1850HD and the 2450 is about 1.25dB. The 1850 HD, like all RMX amps with the "HD" suffix, have better thermal management for use at lower impedances. That's what maked less better than more.

A lower powered amp almost always sounds better than the slightly higher powered amp that heats up and shuts off.

The 808s are great subs. With proper power they should kick ass and take names. Even with less than the optimum amount of power, their high efficiency will give you more output per available watt than a whole lot of other subwoofers.

Check that wiring.

[Daniel Lozada]

Dave - these amps can be bridged via the Speakon outputs as long as the correct Speakon pin-out is used (as Alfredo Cannon mentioned earlier in the thread).  My dealer had Rapco custom build a pair of 10 awg speakon bridging cables for me when I ordered the subs initially.

I've been told before that these amps may be over-rated - they claim something like 2100w at 4 ohms bridged (original spec given prior to them dropping the 4 ohms bridged rating), but I think it would take an absolute ton of wall power to get to that level since they don't seem to be very efficient amplifiers.  They are a Class AB I believe compared to the QSC RMX 1850HD and 2450 being Class H.

I have noticed that if I push the levels on the subs too much the amps shut down - Crown told me they do this when they can't get enough power.  The red thermal lights kick on and the amps do nothing for about 3 minutes or so.  Then they come right back online.  The amps don't get hot to the touch, barely warm at the most.  I have sent every one of them back to Crown to be checked for any problems that would cause them to be weak or shut down early.  I'm not used to amps shutting down when they aren't even hot - I would understand if I was pushing them to the point where they were heating up big time and actually going thermal.

If you see the clip lights for even a second on these amps you can almost bet the amps will shut down within 15 seconds - they have done that ever since I put this rig together.  This has a lot to do with how hesitant I am to really push the system for more output.  I honestly think the amps do great on my mains, but for subs they just can't seem to get enough juice to keep going all night. 

[alfredo cannon]

Dave - these amps can be bridged via the Speakon outputs as long as the correct Speakon pin-out is used (as Alfredo Cannon mentioned earlier in the thread).  My dealer had Rapco custom build a pair of 10 awg speakon bridging cables for me when I ordered the subs initially.

I've been told before that these amps may be over-rated - they claim something like 2100w at 4 ohms bridged (original spec given prior to them dropping the 4 ohms bridged rating), but I think it would take an absolute ton of wall power to get to that level since they don't seem to be very efficient amplifiers.  They are a Class AB I believe compared to the QSC RMX 1850HD and 2450 being Class H.

I have noticed that if I push the levels on the subs too much the amps shut down - Crown told me they do this when they can't get enough power.  The red thermal lights kick on and the amps do nothing for about 3 minutes or so.  Then they come right back online.  The amps don't get hot to the touch, barely warm at the most.  I have sent every one of them back to Crown to be checked for any problems that would cause them to be weak or shut down early.  I'm not used to amps shutting down when they aren't even hot - I would understand if I was pushing them to the point where they were heating up big time and actually going thermal.

If you see the clip lights for even a second on these amps you can almost bet the amps will shut down within 15 seconds - they have done that ever since I put this rig together.  This has a lot to do with how hesitant I am to really push the system for more output.  I honestly think the amps do great on my mains, but for subs they just can't seem to get enough juice to keep going all night.

I'll take the Pepsi Challenge for you. I have both Xls 802 and RMX 2450. I'll run them head to head bridged mono with Danley TH-115 (4 ohm boxes) and I'll let you know the results tomorrow.

[Dave Dermont]

Dave - these amps can be bridged via the Speakon outputs as long as the correct Speakon pin-out is used (as Alfredo Cannon mentioned earlier in the thread).  My dealer had Rapco custom build a pair of 10 awg speakon bridging cables for me when I ordered the subs initially.

Never take anything for granted.

Open up the connectors and make sure they are wired correctly.

Stuff happens, ya know.

If you are using cables from one cabinet to another, make sure they are wired correctly.

CHECK BOTH ENDS!

[Dave Dermont]

Also, I think the Yorkville subs have a way to change the Speakon pinouts so you can biamp with a single four conductor cable and jump the tops from the subs.

Maybe check into that too

[Daniel Lozada]

I'll take the Pepsi Challenge for you. I have both Xls 802 and RMX 2450. I'll run them head to head bridged mono with Danley TH-115 (4 ohm boxes) and I'll let you know the results tomorrow.

Thanks Alfredo!  That would be of great help...

[Michael Storey]

My school dance rig for DJs is 4 Yorkville E15 tops over 4 Yorkville LS808 subs.  I'm running 4 Crown XLS802 amplifiers to power it, and using the recommended Yorkville EP1215 processor for any crossover/EQing that is necessary.  The processor was recommended by both Yorkville and my dealer.  For my larger events I bridge the sub amps and run each bridged mono at 4 ohms...smaller events I just run the amps in stereo.

I typically run the tops in pairs off to each side of the stage sitting up on small scaffolding or moving head road cases, splayed slightly to help eliminate any comb filtering issues.  I usually run the subs center clustered on the floor directly in front of the stage.  The stages are usually anywhere from 18"-30" in height and sit 8-16 feet off the back wall.  As far as the center cluster goes - I just sit them all side by side - I don't stack any of them or lay any on their sides since Yorkville told me there shouldn't be any real noticeable difference.

I think I should be getting significantly more output from subs than I am - I don't know if its something I am doing wrong in setting my gains or if that processor isn't as good for the system as say a Driverack or similar processor would be.  The bass seems to fall off very quickly as you move away from the subs - you can hear it, but you don't feel it.  I was always under the impression this quasi-horn loaded design should allow the bass to carry further than a typical bass reflex (I could be wrong in that assumption - I'm not an expert at all).  I am not a sound pro by an means - I rarely ever provide sound for anything other than DJs and the occasional small wedding band/musician. 

I have wondered for a quite a while if I need to ditch the Crown XLS802s for QSC RMX2450s or 1850HDs?  I get conflicting information from Yorkville and Yorkville dealers so I have just left everything well enough alone for the time being.  At this point I either need to figure out how to get the most output possible from these subs, or sell the system and move into something else.

Your amps are your weak link. After recently stepping up to iTechs, I now know all watts are not created equal. The 4 center clustered LS808's properly powered should definitely have some impact.

Consider stepping up in class of amps (PLX/XTI), or better yet, check out the refurb Yorkville AP6040's on ebay. It's an extremely solid sub amp at $1299 and you might even be able to haggle. I've heard this combo (still own a 6040 and 6020, buddy has 808's) and it rocks.

[Mike McNany]

Someone above posted about running 1500 watts or so to the LS808s. That's what I did. I ran a PLX3002 bridged to a pair for several years. Watch the clipping and they really thumped for a bar band. Only got rid of the LS808s because they were hard on me to move by myself (pre-wheeled models) and we switched to UCS1s. The manual for the Yorkville processor lists wether to use the built-in delay or not and the crossover frequency for their tops & subs. In my case, with U15s over LS808s, that was yes to the fixed delay and 120Hz for the crossover.

Wall power CAN really strangle amplifier performance. While I normally use wall power vice a distro, I also have a large amount of  12awg power cabling to route as many circuits as needed to a common ground unit (that can common ground up to 4 20A supply circuits).

Mike McNany

[Stuart Pendleton]

Mike, I know YOU know what you are doing.  The OP is a DJ so the source is much more likely to be highly compressed material.  That is going to drive average power ratings up.  Since the 808 was rated for 800 watts continuous, are you sure you would still want 1500 watts per cab.  I know you can do that with live material which allows cooling from dynamics, but not sure I would do that with compressed recordings all night.

[Daniel Lozada]

Someone above posted about running 1500 watts or so to the LS808s. That's what I did. I ran a PLX3002 bridged to a pair for several years. Watch the clipping and they really thumped for a bar band. Only got rid of the LS808s because they were hard on me to move by myself (pre-wheeled models) and we switched to UCS1s. The manual for the Yorkville processor lists wether to use the built-in delay or not and the crossover frequency for their tops & subs. In my case, with U15s over LS808s, that was yes to the fixed delay and 120Hz for the crossover.

Wall power CAN really strangle amplifier performance. While I normally use wall power vice a distro, I also have a large amount of  12awg power cabling to route as many circuits as needed to a common ground unit (that can common ground up to 4 20A supply circuits).

Mike McNany

Can you explain that common ground unit a little further? I've never heard of it before. I own roughly 1000 feet of SOOW 12 awg power cabling (split up into 25/50/100 ft lengths) to cover all my power needs and I have a distro available from a larger production company that I use for larger sound/lighting needs.  Unfortunately I almost never get to use that distro because the venues don't have the hook up for it - only one local venue has the proper hookup. 

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