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In the Forum: Horn-Loaded Speakers
In the Thread: Jessie Dazzle Project
Post Subject: Right again...Posted by jessie.dazzle on: 7/9/2008
Ok, it turned out that I had all caps and coils "in stock" necessary to adjust the filters very close to Romy's recommendations.
Its still not perfect, and I had the mic 1m from the membrane of the driver (had not yet read Romy's last post where he recommends putting the mic back at listening point). Also, the RTA was giving me hell (locking up due to registration paranoia on the part of the maker of the software... Was not able to arrive at a satisfactory setting). All that aside, what I got looks amazingly close to Romy's drawing (see previous posts):
Looks like the low end of the Upper-mid curve should move to the left a little. I will try changing the caps tonight.
Though the filters for the lower-mid driver should allow it to go lower than the previous arrangement, it does not seem to be doing so, and is rolling off at the low end in a more progressive manner. It is also somewhat attenuated relative to previous arrangement (a good thing).
I didn't have a 2.7mH coil as recommended, but in doing the calculation, I came up with 4.5mH, which I happen to have in stock, so I put them in the game, each coil preceded by a 10uF cap. I will try taking the horn lower but need to do a bit of shopping for parts.
How it sounds :
It was 3 AM when I realized my neighbor was gone for the week (which means I can actually listen at interesting levels after 10PM : See previous posts). I listened until around 4 AM (facing the DAY JOB was just painful), so I need to listen again when rested, but first indications are that Romy could not have been more right.
Here is what I noted : Rendition is over all more precise, seems like a reduction in noise, system capable of more delicacy, more intimacy, seems like upper-bass/lower-mid has more weight, texture of instruments in the mid-range even more apparent now. Quite addictive.
Romy wrote :
"...I personally do not feel that you use Fundamentals Channel properly. You desired to run your Fundamentals Channel up to 3200Hz but it is too high..."
Yes, it seems you are correct. Arriving at this conclusion alone would have probably eventually happened (well I like to think so!), but I was reluctant to try such a thing because, to be honest, I had always thought you under-used your Fundamentals horn due to the difficulties you had in implementing it. I have often wondered if you were not supplementing the output of that horn via your Injection Channel. I now see (hear) for myself that neither is the case.
Regarding RTA resolution and display :
I took a look at some of the sweeps you've posted for the S2 and Water Drop tweeter; it seems you tend to use a 40dB window... This I think I could manage. I find reading your RTA sweeps seem a bit coarse to me for example when trying to read HF rolloff of the S2, but this may be because you were using something like a 1/3 octave setting at the time (?)
Regarding the tone generator possibly freaking out, Romy wrote :
"...If you have doubts about your generator, use any good test CD..."
Yes, I remembered that I had a couple such CDs, which I used in this latest round of testing.
Thanks again for the help,
jd*Rerurn to Romy the Cat's Site