4 Attachment(s)
Pleasant surprise, bringing it all back home:
Getting the 2407H to play nicely two-way required considerable effort, particularly with respect to constructing a 24 dB/octave crossover for it.
http://audioheritage.org/vbulletin/a...id=12483&stc=1
Looking at the HF compensation, though, the curve appeared "textbook," i.e., 6 dB/octave compression driver. 1.2 kHz 3120A crossover would provide that. Indeed so, but it's only two poles. Worth a try to verify, tho, here with 2407H on PT-H1010 waveguide:
http://audioheritage.org/vbulletin/a...id=12484&stc=1
So, what crossover do I have that's 24 dB slope with textbook 6 dB/octave compensation? Active JBL M552/3 is what. Enable the 80-Series HF boost, and here's the results, all playing 2407H within +/- 2.5 dB and better:
1) OASR "Dr. Seuss" horn
2) PT-F95 "El Cheapo" waveguide
3) PT-F64 (with JBL 1" throat adapter)
4) PT-H1010 (also with adapter. Zilch's favorite PT-F1010 similar.)
Uncompensated curves (no filter) for PT-H1010 here:
http://audioheritage.org/vbulletin/s...&postcount=776
To try out the 2407H, 3120A or M552/3 with CD compensation enabled will get there expeditiously....
2 Attachment(s)
small talk to damping question....
Quote:
Originally Posted by Zilch
Hi, Jean!
Somehow, I KNEW you'd have ideas on this! ;)
I'm surprised we don't see more of it today. The thick composite resin ones are inherently damped, I appreciate, but some of the metal ones could be hung outside as wind chimes.... :D
Hello Zilch,
Long time…
You a DYEman now…
Yes I have few ideas on this question but first I tried to keep your feeling…
In regards on your set-up it is clear you not fix horn into a standard wood panel.
The mass of wood panel + the rest of weight box contribute to damping and it is probably caculated by engineer: Big chance the ringing is out just by fix it…
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For the damping question:
Asphalt, lead or bitumen elastomer or any other hight viscosity damping is poor product audio:
Why ?? this stuff is degrading the transient response. Slow peak but long-time resilience energy effect. This thype of product pick-up energy and re-radiate slowly. The peak to peak is better but the floor noise is poor and blomm the attack of next response by lack of transient and maintaint higher internal noise in time.
See picture for more comprehension.
The other problem is tuning visco damping. If the damping is not tuning the result is poor than original situation . see picture 2 the maximum dampoing create a very hight peak response than original… the best damping in this case is 0.2 damping . So be careful to not create a displacement of coloration by excessif damping….
in fact structurally damping is really better approach than visco damping so never good cie go in the way of visco damping.
:cheers: