Sitting Room Build: Jack 12 Lite

[HugoMack]

So..... I tried agin using 1khz sine wave, and this time got a stable reading. I know what the power amp vol control positions for the two channels at that level. But now with the DBX connected, I can't get a stable voltage reading.... Hmmm, having turned off all the functions of the DBX, still getting variable voltage readings. A new DMM is required (the current one being old...)

[Ryan Sober]

So..... I tried agin using 1khz sine wave, and this time got a stable reading. II know what the power amp vol control positions for the two channels at that level. But now with the DBX connected, I can't get a stable voltage reading....

Turn AFS off.

[HugoMack]

Everything's off on the dbx - and back to unhooking the dbx and going direct from desk to power amp, the same half second voltage changes

But now it works OK using a 1khz sine wave....

So now - hooray - I've set it to limit to just under 40V, which in the dbx display shows as a reduction of 18db. does that make sense? (2 x 400 watt amp @ 4R ). The limiter is coming on at -5 db on the desk main output - with the input channel for the link noise at 0db... Anyway, the limiter comes on immediately which is what I want

I'll have to wait until I have another gig to relate what I've done to volume levels. But it makes sense following my pervious experience.

@Grant and Bruce, I don't have the luxury of a nice outdoor yard (and neighbours in the next grid square) to hook everything up and test it. I can only crank it to gig volume at a gig, although when I complete the subs, I'll hire a village hall or something to get it all set up properly.

But it looks like my Jack12 Lite full-range configuration is now set up. Many thanks.

[Ryan Sober]

Everything's off on the dbx - and back to unhooking the dbx and going direct from desk to power amp, the same half second voltage changes

But now it works OK using a 1khz sine wave....

So now - hooray - I've set it to limit to just under 40V, which in the dbx display shows as a reduction of 18db. does that make sense? (2 x 400 watt amp @ 4R ). The limiter is coming on at -5 db on the desk main output - with the input channel for the link noise at 0db... Anyway, the limiter comes on immediately which is what I want

I'll have to wait until I have another gig to relate what I've done to volume levels. But it makes sense following my pervious experience.

@Grant and Bruce, I don't have the luxury of a nice outdoor yard (and neighbours in the next grid square) to hook everything up and test it. I can only crank it to gig volume at a gig, although when I complete the subs, I'll hire a village hall or something to get it all set up properly.

But it looks like my Jack12 Lite full-range configuration is now set up. Many thanks.

Strange. Glad you got it sorted. Sorry for being presumptuous; the AFS has caused quite a few headaches for some of the folks around here, and it seemed like the same symptom.

[HugoMack]

[quote]Sorry for being presumptuous; the AFS has caused quite a few headaches for some of the folks around here, and it seemed like the same symptom./quote]

Don't worry Ryan. Grateful for your help. I'd disconnected the dbx several times, turned everything off at least twice, and there'd been previous "turn off AFS" suggestions earlier.

For some weird reason, my DMM doesn't seem to like sine waves below 1khz unless they're actually on a speaker terminal with the speaker in action.... DIsconnected, it seems to need the higher freq. There may be a good and electronically-complicated reason for this. Or not....!

[Ryan Sober]

Don't worry Ryan. Grateful for your help. I'd disconnected the dbx several times, turned everything off at least twice, and there'd been previous "turn off AFS" suggestions earlier.

For some weird reason, my DMM doesn't seem to like sine waves below 1khz unless they're actually on a speaker terminal with the speaker in action.... DIsconnected, it seems to need the higher freq. There may be a good and electronically-complicated reason for this. Or not....!

That's what I get for not reading the thread...
Sounds like a hokey DMM, then... or it could possibly be that the amp doesn't react to no-load situations gracefully. I've noticed that SMPS amps are hit-or-miss for behaving nicely in no-load situations.

[HugoMack]

Your SMPS observation fits with my experience; the DMM was cycling through about five voltages that were more or less the same for each attenuator setting.

Only when I set the tone generator to 1khz and left it for a bit did the DMM reading settle to a definite and expected sort of voltage, which I was able to set at just below 40v.

But I'm pleased to see that at this setting, the limiter is limiting to the right sort of level at desk output max.

I really am very pleased with the dbx - and the principle of loudspeaker management dsp's - which I'd never used before.

On the Harman dbx site, the FAQ section strongly advises against using the AutoEQ RTA indoors. I wasn't able to get it working at my trial run gig (it insisting that the mic cable was u/s). I've asked questions but this site seems pretty unresponsive (or maybe I'm asking stupid questions ) So I guess I'll just get it going and see. The AFS seems to work really well.