I bolted a 476Mg to a 9800 horn yesterday and ran a curve.Originally Posted by hlaari
1/12 octave smoothing. No gating.
It looks reasonably well behaved to me.
Unless JBL sends me a 4338 horn presently, I won't have one freed up to measure for a few months.
I have zero interest in the 4365 horn (too big and too difficult to get).
Same 476Mg bolted to the PTH95HF.
This combination works best active. I set a 6 dB/octave high pass filter at 8 kHz and it flattened the entire curve out reasonably well.
Passively this is simply a 1.6 uF capacitor in series. Putting a 15 ohm resitor across the 476Be flattens it out a bit more. A couple notch filters to fix the bottom end and it's done. Arguably better to just go active and use DSP.
As intended, the waveguide isn't worth much below 1 kHz.
Could I ask you to measure a 476Mg on an array horn please if/when you have time? Or maybe I missed when you did in the past?
Always fun learning more.......
I'll have time by the end of the weekend.
Thank you sir!
Always fun learning more.......
It will sound great. You need a massive notch circuit to subdue the 2 kHz hill, but it is simple to do. The rest of the curve is easy to deal with. Looks like you can have a 700 Hz or so crossover. Very nice.
Ok, I dragged out a Citation 22 so I could get some decent curves of one of your 476Mg's on each of the three horns I currently have available. The H4338 is currently in use and I didn't feel like unbolting an entire system to run a curve; That will teach me to incorporate a horn into a loudspeaker enclosure now won't it!
You can't really do anything with these curves. They're merely for comparison purposes. 1/12th octave, no gating, just raw data with noise and all.
Maybe later today I'll bolt up some 476Mg's to the H9800's, put them in place of the Array horns over the 2206H's, then get out the miniDSP and see what happens.
Thank you very much 4313b!!
I just wanted to have a comparison from "A known good source"before I attempt to measure them here and screw it all up!!
I was thinking of getting out the mini as well and trying an active solution on my current Be arrays and working out some DSP on those as well.
Always fun learning more.......
I did get the mini out and everything all hooked up. I had to swap out the top Citation 22 on the 476Mg's and put an Adcom in with variable input so I could get the gain down far enough to kill off the hiss. With the Adcom three quarters off, it worked out well, no hiss. I had 100 uF protection caps on the 476Mg's just because.
I ended up with a 48 dB/octave filter at 700 Hz, a high pass shelf set at 6 kHz with Q of 1.4 and boost of 9 dB, and a peak filter set at 4.2 kHz with a Q of 8 and boost of 3 dB and it all sounds decent enough. The mini is definitely as good as mp3, probably better. I did compare a couple mp3's to cd's and the cd's were obviously better.
They would have to be set up in my listening room and given an extended listen over a few weeks though to determine whether or not that was all the EQ needed. I suspect a bit more is needed. Baffle step compensation, slight trough in the 4 kHz to 6 kHz region and perhaps a dB or two less above 15 kHz. Given that they aren't for anything permanent, I highly doubt I'll bother.
I wasn't expecting such broadly similar responses across the 3 horns..
The waveguide is arguably the easiest to use between 1 kHz and 10 kHz, which is probably one of the reasons why it has been so popular. I believe Earl K mentioned that many years ago. The miniDSP allows for delay so the greater depth of the waveguide can be negated.
The sonoglass horns sound better but they need a bit more work to measure nice. They typically end up with two or three notch filters.
I am very interested in the M2 waveguide, still not available as of last week.
One thing I wanted to verify with the miniDSP was that all the settings could be done on the fly in realtime and they can be. It's a fun little hundred dollar gizmo.
I ended up reducing the 6 kHz shelf from 9 dB to 6 dB because hot (flat) tops ends just bother me after awhile. Same thing happened with all the JBL four-way Studio Monitors, I always ended up with the compression driver and slot-loaded ring radiator around the 8 or 9 o'clock position.
Thanks 4313b for the "endeavor" into minidsp territory. I will try those settings as a starting point when the time comes!
Always fun learning more.......
The H9800 and Array horn are sufficiently different that you will have to use different setting.
Since you can do it all in realtime it should be fairly easy to get dialed in rather quickly.
The only real question is if the miniDSP can be left in the chain in a high performance loudspeaker system. That's your call.
Yes that part is the key. We will see just how well it performs vs a good cc'ed xo to my ear.
Always fun learning more.......
4313B,
Have you had the privilege to hear both 476Be and 476Mg? As I understand it, the only thing that tells them apart is the diaphram beeing different. Are they more or less equal sonically or is there a significant difference?
/Mostly
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