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In the Forum: Audio Discussions
In the Thread: A listening room for a domesticated Cat?
Post Subject: About the use of reading my own site.Posted by Romy the Cat on: 7/13/2017
 Romy the
Cat wrote: |
| If I defeat the hardness by dropping of the output impedance then I
would understand what is going on but I minimize the hardness by raising the
output impedance!!! This is very interesting and I need to think about it more.
|
|
It is very useful to read
my own site and my own writing to confirm that I was an idiot. Tonight I had a
long listening session that included a spectacular (!!!) rendition of Mahler 3
by
Semyon Bychkov and
Cologne Symphony. In the middle of the
last movement it came to me that, as I did a few times before, confused the
direction of drivers damping. It is in reversed logic: the dropping the plate
voltage increases the output impedance and DECREASES the damping of the drivers.
As it “got” it the things are clearly revealed to me: I just have the over damped
drivers. I got a resistor in series with the driver and the result was as
expected: drop in gain and increase in lower end dynamics. Ok, now we are in a sensible
business. I decided to go for radical measures. I opened up the midbass boxes
and got rid all of the foam from them. The driver’s Q raised and now driving
the underdamped midbass with idler amplifier I got my lower knee compression
gone. It is VERY nice and I am very happy.
Very happy about the tightness, hardness and compression that has been gone but not about the rest of the things. The
sound did become uglier but in an understandable way now. As the damping become
less and the driver is not so much “held” but the amplifier output the driver act
up more flamboyant in term of frequencies response. If before my tricks with writing
a slope from 140Hz to offset my 60Hz 10dB peak “kind of worked” and did not has
too much tonal coloration but now it does not work anymore and I have very well
defined tonal problem in the mid of my midbass.
Well, this is already
easer thing to deal with, perhaps easer inly become there is no mystery about
it. I need to spend some time with RTA and to find out where it comes from. Is it
room, or it is some phase rolling out, or it is just one channel position. I do
not know yet. I for sure do not want to write the notch filters to kill the
thin and I would need to learn where it come from and how to address it naturally.
I do not have fantasy that it will be easy. In worst case in my past if the
room has the mode like this then I fixed it by slicing the channels in there
and used the both slopes corrected the room problem. The 60Hz is VERY
uncomfortable region for me and I would like do not have two midbass. Even if I
use each of the drivers “before and after” 60Hz then I do not think the lower midbass
will have the gain to get my SPL. So, I need to fine what my 60Hz peak come is
from. It will be another day…
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