JBL Concert Series 4852A tops/4842A bottoms - xover points?
dan
Posts: 25
I have the older JBL Concert Series system, 4852A tops (2-2206H 12's) and 4842A bottoms (2-2241H). I'm looking for crossover points?
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Hi pass sub 30Hz BW18
Lo pass sub 80Hz LR24
Hi Pass mid 80Hz LR24 No overlap!
Lo pass mid 1.2 - 1.3KHz LR24
Hi pass highs 1.2 - 1.3KHz LR24 (Match mid lo pass frequency)
My friend in Las Vegas swears by a lower mid-high XO point. He goes with 933Hz and insists it removes a noticeable amount of JBL sound from the speakers and means it in a good way. I will be trying the 933Hz XO point this weekend for the first time and will report back Monday.
Dennis
And I might add that I did find this 933Hz XO point in one of the many JBL SR tunings on their website.
I did the JBL site search before I posted to this site and found the 4850 (concert series) information in the \"Vintage\" section, but it does not provide any xover info. I also looked at other JBL systems with \"similar\" componets and their xover points seemed to be 80 & 1.2, just as you recommend. So I guess I'll play with those settings...
Dan
G
As promised, I am reporting back with results of the 933 Hz crossover point on JBL SR4732A (similar to JBL Concert Series minus the flying hardware). The test was done on a two day Cinco de Mayo festival.
So, I ended up using a 933 Hz BW24 xo point because LR24 didn’t behave well for me. I didn’t “flatten� out the response of the system with a RTA and a butt load of filters. I used the Magnitude trace in SMAART and gently “leveled� the response with as few filters as possible. I did not address every little peak or dip. The tech folks at Meyer always suggest “broad strokes�. You may ask how that applies to old JBL and I don’t have a snappy comeback but it is still how I approached it. I used mainly ground plane measurements but also did a few with the speaker box standing upright and then I averaged the measurements before applying any PEQ filters
I had mentioned a friend in Las Vegas successfully used the 933 xo point and he used a BSS FDS 366T Omnidrive. I decided to use the same processor so we could “compare apples to apples� when we compare notes later.
Out of the gate, the system sounded good. CD playback was fat and required no additional EQ. Same with a vocal mic…….full sound with no “harsh�. The system continued to impress me through the daytime bands that drew a medium size audience. As we went into the late afternoon and evening, the temperature dropped and the audience grew. The system started getting pushed harder and started sounding like JBL again. The “harsh� came back and the 400-500 Hz honk reappeared. Both of these issues are hard to deal with when the system is being pushed.The system being stacked on \"sound wings\" that were attached to the stage didn't help. My initial take on this exercise is to compare it to putting lipstick on a pig BUT I haven’t given up. There is always the human factor. I was doing monitors for this festival and while I could walk out and listen to the main system, I wasn’t “hands-on� and I don’t know what was being done in response to each issue as it came up. I will post again after I do a FOH gig with this system.
I think the 933 xo point is a positive step and after you become accustomed to your system’s response with a 1.2KHz point, try the 933 point and compare. Leave a post with your impression of the outcome.
Dennis
I can't argue the point your making but temperature, humidity, and the crush of a couple thousand human bodys (water bags) takes you places you don't anticipate. Setting the system up at the loudest expected volume in an empty park will be of some help but it won't sound good in the early part of the day with small crowd. I find I have to follow the venue conditions as the day progresses and make EQ changes accordingly to keep things consistant(ish). I have to return my EQ to \"morning start settings\" for the next day.
We finished striking equipment about 1:30 this morning. I'm tired, sunburnt, and every muscle hurts. Promise me I will never have to do another festival and I will send you $10! I'd make it more but the economy you know.......
Dennis
I Promise...
Ok, but I have set up @ the max volume because it's the one WITH the most people... and thusly the \"money shot\" I have found that if I set up for the inevitable, use the \"judicious compression scheme as posted in my \"Compress the whole mix? 101\" and use the GEQ that is esentially bypassed (flat) during the \"big show\" to help with the lack of water bags, and \"wind and water\" I have found that the \"early bands\" are usually less professional, have performances that are \"less practiced\" and all over the place dynamically...and so the light compression scheme and judicious equalization that I can easily return to baseline for the money bands serves me well...
I really wish there was more money in this business.. I can only justify it because I love it! :roll:
G
I'm still tinkering but used your recommendations as a beginning. I do remember something from the old pro-audio days about the 933 xover point, but that was a long time ago and can't really remember the details and/or results.
Thanks, Dan