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Old 6th January 2016, 08:06 PM   #351
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Quote:
Originally Posted by billshurv View Post
the post 1 circuit or the post 30 circuit?

EDIT: correction he did 3 designs in the end. another one on the last post.
The post 1 circuit. The one in post 30 has no component values and does not seem to be a fully worked out design.
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Last edited by DouglasSelf; 6th January 2016 at 08:09 PM.
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Old 6th January 2016, 08:13 PM   #352
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Quote:
Originally Posted by scott wurcer View Post
The 1kHz sampled at 44.1K a 32K length record can't contain all 64k codes at one obvious level, but an interesting thought experiment. At a 64k record a ramp from plus to minus full scale does, it there a sine wave at another frequency that touches exactly each code once in 64/44.1 seconds?
Scott
If I am not bothering you much, what these 64k and 64/ stand for?
I had a day dealing with numbers and FFTs and now I am even more slow than I am during a good day

Sorry for corrupting the thread guys

George
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Old 6th January 2016, 08:43 PM   #353
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Originally Posted by gpapag View Post
Scott
If I am not bothering you much, what these 64k and 64/ stand for?
I had a day dealing with numbers and FFTs and now I am even more slow than I am during a good day

Sorry for corrupting the thread guys

George
To be honest, it would be better if you could take this to a separate thread.
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Old 6th January 2016, 08:44 PM   #354
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Going back to this reference:

35] Lawson, J "Rumble Filter Preserves Bass" Letter to Electronics & Wireless World, April 1992, p317

Lawson gives two earlier WW references for the LF crossfeed idea:

Macaulay J P, Circuit Ideas WW Sept 1979, p75

Lagvad J, Letters WW Mar 1980, p61

and it would probably be easy to find earlier ones. You could argue it's a fairly obvious idea. I wonder if these two work?
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Old 6th January 2016, 09:01 PM   #355
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I have now checked the Macauly circuit. It's a beauty, and I expected no less from Macaulay, who haunted the Letter columns of WW for many years.

Firstly, there is a +0.5 dB step below 100 Hz for in-phase signals. Not dreadful, but very clearly not flat.

Of greater moment is that it shows 6 dB of gain for anti-phase signals below 100 Hz. It's worse than nothing.

The original circuit used discrete transistors and I have converted it to opamps, keeping the significant values the same.
I think the sims are sound, but I do wish someone else would check.

I'm starting to understand why this notion has never seen commercial use. Now, for Mr Lagvad...
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Old 6th January 2016, 09:10 PM   #356
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Quote:
Originally Posted by gpapag View Post
Scott
If I am not bothering you much, what these 64k and 64/ stand for?
I had a day dealing with numbers and FFTs and now I am even more slow than I am during a good day

Sorry for corrupting the thread guys

George
To exercise all codes in 16 bits you need at least 64k codes...
Sorry Douglas.
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Old 6th January 2016, 09:29 PM   #357
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So far Mr Lagvad wins (I'm not including my effort in the contest) as he published something that more or less works.

It has a damn-near flat response to in-phase signals. (+0.02dB peaking)

Unfortunately the slope of the anti-phase suppression is only -6dB/octave, and there is +2 dB of anti-phase gain around 135Hz. There's the trap...


I've got a fourth-order Devinyliser, and I'm not afraid to use it.
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Old 6th January 2016, 09:40 PM   #358
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Sorry for being dim, is there a general WW archive were we can find the letters?

I'm zero use on the SIM front but trying to wrestle a re-installed audacity into submission to see if there is anything that can be done on some real files for testing.*

I do need to mimble off and reseach something that is troubling me and too stupid for me to ask here though.

*Note that whilst this is opening up all sorts of avenues for experimentation for which I am grateful for the nudge I have to admit that all the best 'ambient soundstage' I have heard in my system has been off CD.
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Old 6th January 2016, 10:16 PM   #359
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Quote:
Originally Posted by jan.didden View Post
To exercise all codes in 16 bits you need at least 64k codes...
Sorry Douglas.
So k in this case means kibibyte(kiB)=1024byte. Therefore 64k (binary) means 65536byte (decimal).
Now we communicate (on another thread)
Thanks for the patience.

George
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Old 6th January 2016, 10:49 PM   #360
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Quote:
Originally Posted by DouglasSelf View Post
.....The original circuit used discrete transistors and I have converted it to opamps, keeping the significant values the same.
I think the sims are sound, but I do wish someone else would check.
...
I've been busy but will try to look.
My opinion is that high order filters could cause obvious leaping about when piano or bass guitar are playing notes around the cutoff. The group delay may also be an issue
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