Hi Guys, so I have a set of these powered JBL speakers- 2 15's and a horn I believe. The amp module, and specifically the "input module" has gone out and is NLA. My quick thought was just turn them into passives as we have plenty of power amps laying around. Can anybody help with a crossover design? What do I need to know about the drivers and cabs?
The best time to measure active speakers for conversion is while they are still working. At this stage, what you propose is possible but you will need to design the crossover yourself.
There are many and varied ways to do that and a lot will depend on how far you will go and how you will proceed, whether you will measure then design, or tweak and measure as you go, whether you want fast results etc.
There are many and varied ways to do that and a lot will depend on how far you will go and how you will proceed, whether you will measure then design, or tweak and measure as you go, whether you want fast results etc.
Good, but even if you didn´t, brochure or user manual will certainly mention crossover frequency.
Then any reasonable 12 or 18 dB/octave crossover which can handle the power involved "should" work as well as any other one.
You won´t have the bonus little peaks and dips here and there offered by the Factory original 0ne to flatten response even further, but in any case the cabinet will be very usable.
Here in Argentina that is done all the time, even if available, a replacement module costs more than a new cabinet because of distance,freight and Customs, I see everywhwere small PA companies stacking random brand cabinets on stage sides, on inspection many just have a piece of plywood covering the plate amp hole with a ocuple speakons only, obviously there is some passive crossover inside.
I suggest you add a protective light bulb (say 12V 12-15W or 24V 30-45W depending on driver actual power handling) in series with HF drivers.
Kludgy as it seems, they often sound quite good.
Then any reasonable 12 or 18 dB/octave crossover which can handle the power involved "should" work as well as any other one.
You won´t have the bonus little peaks and dips here and there offered by the Factory original 0ne to flatten response even further, but in any case the cabinet will be very usable.
Here in Argentina that is done all the time, even if available, a replacement module costs more than a new cabinet because of distance,freight and Customs, I see everywhwere small PA companies stacking random brand cabinets on stage sides, on inspection many just have a piece of plywood covering the plate amp hole with a ocuple speakons only, obviously there is some passive crossover inside.
I suggest you add a protective light bulb (say 12V 12-15W or 24V 30-45W depending on driver actual power handling) in series with HF drivers.
Kludgy as it seems, they often sound quite good.
Frequency Range (-10 dB): 45 Hz – 20 kHz (EQ in flat position) Frequency Response (±3 dB): 52 Hz – 20 kHz (EQ in flat position) Coverage Pattern: 70° x 70° nominal Directivity Index (DI): 10.3 dB Directivity Factor (Q): 10.8 Crossover Modes: DSP controlled 48 dB filter slope Crossover Frequency: 1.6 KHz System Power Rating: 650 W continuous, 1300 W peak
48dB!!!
48dB!!!
Yes, that's a lot. If you can learn why they did that you can shave an equal amount off each side.
If you also measure the impedance of the separate drivers then you have what you need to simulate a copy of the original.
If you also measure the impedance of the separate drivers then you have what you need to simulate a copy of the original.
Your other problem might be that the JBL 265F woofers are 2 ohm drivers (the JBL 265F-1 drivers are)