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Scientific Discussion / Some embassment about a few of my demos.
Last post by jsdyson -
After some review by some pros (and re-review by me) -- we finally determined that a few of my demos are not DolbyA encoded -- that is one of the troubles, because some kinds of material are difficult to detect either way (believe it or not.)  The recordings either had significant amounts of treble boost and/or HF compression effects.  The songs were by Dionne W and Nat King Cole.  The rest of the material (mostly during/after 1960's pop examples & Mancini) are encoded.  I was really embarassed, but got caught up in the 'fix everything with a screwdriver' syndrome.  I am still wondering a little about DionneW, but I am erring on the side of caution.

One positive item of note -- the decoder has LOTS of enhancements from the basic 'theme' -- still being able to accurately decode DolbyA -- it also avoids creation of distortions resulting from dynamic range expansion.  SO - the typical distortion artifacts from gain expansion are incredibly well suppressed.  Pure/simple expander distortions are not able to be used for indicating a lack of 'hand in glove' expansion, but one has to listen very carefully for stereo image problems, gating kinds of behavior or very muted HF sound.  These just didn't happen on either of those two albums.  Usually, like on my Mobile Fidelity Supertramp (Crime of the Century, AFAIR), there are several bad artifacts when trying to decode material that isn't in the state of being encoded.

I would NOT suggest using the DA compatible decoder as a GP expander or single ended NR (esp because I have better technology in the pipeline), but it does sometimes almost/weakly work.  Specifically the examples from those two artists had a 'veil' on the sound that kept on irritating me, and I suspect that I should have been more critical.  There was something wrong with them, but they generally sounded so good that I kept them.

The Carpenter's and other pop examples (the S&G example, however imperfect, even shows some of the LF distortion cancellation from DA decoding) still have the appropriate pre-decoding artifacts, and I carefully double checked the results.  In some cases, the examples might have been further compressed upon previous DA encoding, but the decoder is VERY GOOD at recovering the DA encoding in difficult cases.  (It isn't using any of my adaptive techniques, so will definitely sound bad when it is presented material that is far from encoded, esp totally uncompressed.)

It is just that Nat & Dionne sounded so good!!!  As I find where I have posted the examples, I have been removing them with a bit of embarassment.  The odd thing is that there was also a definite point where the so-called 'decoding' worked best...  Really kind of weirds me out, but gotta move forward, right?!!?

I don't have an infinite sized collection, and have only a few more recordings that I might try out -- hopefully I can find some more to replace the previous erroneous ones (and more carefully test next time!!!)   Buuuttt...  I so much liked the music!!!

General Audio / Re: Album Art Downloader XUI
Last post by AlexVallat -
Huh, you're right, the version there is incorrect. It's correct in the source ( and in the released installer/zip, but in the Updates.xml it's wrong. I've re-uploaded it now from the master copy, so once Sourceforge updates its caching it should work properly. Or you can download it directly attached to this post. Sorry about that.
General Audio / Re: Album Art Downloader XUI
Last post by AlexVallat -
The discogs script should already have import AlbumArtDownloader.Scripts at the top, just above import util!

I don't know why you are getting the error about SecurityProtocolType. That's just part of the .net framework, in System.dll, so there's no chance that's not present (or nothing would work). I've tested with just and in the scripts folder, and it compiles fine for me, so there's something else weird going on with your setup.
General Audio / Re: Strange frequency spike near 18kHz in song
Last post by blurry_light -
It is 3d - time axis, frequency axis, and colour for signal strength.


Well, technically the waterfall / voiceprint is a 3D graph: time (x), frequency (y), and intensity (color).

You can do a surfc() in octave, which will give you a nice surface plot with contour lines.

All right, I'll see if I can get to that in a while; I'm going to get busy with other things this week, so it may take a while.
General Audio / Re: Album Art Downloader XUI
Last post by Fiatt -
I've made a little modification into the script, i had at the top:

Code: [Select]
import AlbumArtDownloader.Scripts

Now the message is:
Code: [Select]
Searching for scripts...
Found 2 files: [,]...
Loading references: [System.Web.Extensions, System.Web]...
Compiling scripts...,75): error BCE0005: Unknown identifier: 'SecurityProtocolType'.
General Audio / Re: Album Art Downloader XUI
Last post by Fiatt -
I made a clean uninstall via windows and reinstall the app. No luck. Still have the discogs script into the folder but unable to compile it.
same message.
Audio Hardware / Re: Active setup help and recommendations
Last post by patate91 -
I've never used the miniDSP but can't you adjust/balance the levels with it???   Volume adjustment is about the "easiest" digital signal processing you can do!

Yes it's possible to adjust digitaly for every output. I'm confused on how digital volume works. I've read that lowering volume would lower the number of bits. Also that there's a possibility to raise SNR.

I hope you're measuring your room?    ….Diagnosis before treatment!     But, you need to measure your room & speakers together so you can't finish the room treatment before the speakers are done.

Yep I bought a umik-1 and did a lot of measurements. I'm still waiting for some comfortboard to arrive.

Horn loaded compression driver : TAD TD-4002, 110db/w
Woofer : TAD TL-1603, 97db/W
I assume you'll be making some measurements (with a horn attached and the woofer in a cabinet)?

I already measured the horn while investigating a ~ 1 khz to 2 khz dip (that the reason I want to test an active setup and to change crossover 800hz to 600hz or 650hz). As well as speakers, mostly in room due to size. It won't be a problem to level match woofer/driver with the DSP as well as Time align them.

The Internet says the compression driver is 16 Ohms,.  If that's true that means half the power compared to 8 Ohms (-3dB).    (With the same amplifier & settings).     Do you have the gain (or sensitivity) specs for both amps?

I have on hand for experimentation a :
Pioneer SA-9900 for woofers
Luxman R-114 for drivers
There's not a lot of informations about this one on Internet.

If your speakers have an existing passive crossover, maybe you can figure-out the (existing) high-frequency attenuation.   There should be a voltage divider (AKA a "pad"), or a potentiometer or a series resistor.  

If there's a potentiometer it's probably audio-taper (non-liner) and you'd need a multimeter to measure the resistance ratio where you like it.

Crossover is tad TN-4  woofer 36db/oct, Driver 12db/oct. No pot (I had one but I removed it since it is not needed. Parts for the crossover are covered, so I didn't break anything in case I would sell them.

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