JBL AM7212/64 x-over Point
jalo07
Posts: 2
We recently purchased four AM7212/64 speakers for our main sanctuary. The installer configured them in stereo bi-amplified with a Crown DSi 1000 for the HF and Crown DSi 4000 for the LF. I checked the amp's configuration after installation, and the only settings that were made were x-over points and -3db limiting.
The x-over point he set in the Crown amps was 1.2kHz with a 24dbs slope. However, according to the spec sheet, the internal passive x-over is set at 1.8kHz. Should I change the x-over point to match the internal x-over?
I have noticed that this installer wants to x-over every speaker at 1.2kHz, as he did with our previous speakers, which were spec'd to x-over at 800Hz. Is 1.2kHz some sort of standard I don't know about? I am more naturally inclined to follow specifications, as that is what the designer intended.
Also, we have a dbx DriveRack 260 that he completely removed from the system. Should I add it back, turn off processing in the amp, and use the x-over and DSP in the DriveRack 260?
Comments
if anyone else cares to know here is my response from support:
"We do recommend moving the crossover point up to the 1.8kHz listed on the cut sheet, for closest performance to published specs. Crossover points can vary widely, from 800Hz as you mention up to 2.8kHz in some boxes, it largely depends on the physical response of the LF and HF drivers used and the design intention of the unit- given this, your inclination is spot-on, these specs are provided so they may be used to get the best possible sound from our products. Regarding the DriveRack, these boxes don't appear to have any specific tuning presets for those units, so the amplifier DSP should be just fine. Hope this helps!"
PAUL THOMAS
Technical Support Engineer
Harman Professional Solutions
This is an interesting question! It is indeed important to follow the specifications that were set by the manufacturer to ensure optimal system performance. If the internal passive crossover is specified to operate at 1.8kHz, it is advisable to set the active crossover to the same frequency or slightly lower to avoid potential misunderstandings in the operation of the components. However, 1.2kHz may be chosen for a specific specification or sound feature that the installer is trying to achieve.
Regarding your question about the dbx DriveRack 260, this can be a very useful component as it provides more precise tuning and control over the sound system. If you want to get maximum efficiency and more possibilities for sound correction, it is worth returning it to the system. Using Nocramming https://nocramming.com/numerade-review to adjust the DSP will help to optimize the tuning process and avoid unnecessary losses when adjusting the crossovers and processor.
Overall, it is important to take a comprehensive approach and ensure that all parts of the system work in harmony to achieve the best result.
Thanks!