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Old 10th January 2010, 09:50 AM   #2261
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Originally Posted by Legis View Post
What comes to DCX's other features, I noticed that only way to mess the sound is to use auto-align. Does your DCX also give different delay-settings every time with auto-align?...Where is the problem? Used mic is Behringer ECM8000 measurement mic.
I use the same mic. I think the auto-align stuff is just about useless. The corrections for my system were just plain wrong. I don't think its nearly sophisticated enough to deal with the real world acoustics of a small listening space or speakers with closely aligned drivers.

That said, the digital delays look pretty bullet proof. You just need to measure and input the distance you need and the DCX does the rest, including changing the delay based on room temperature (which is pretty cute, although I'm not going to measure the temp each day and adjust the delay to my sub-woofer).
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Old 10th January 2010, 10:02 AM   #2262
mige0 is offline mige0  Austria
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Originally Posted by Gary P View Post
Have you tried the BlueCat gain control?

Gary
Handling and GUI is superior for the purpose of volume control from a dedicated plug-in - of course !

Yes, IIRC the BlueCat was one of those plugins that had compromised performance at attenuated levels.

Theoretically the problem starts already as soon as there is *any* attenuation – if i'm right on that its a calculation / interpolation problem.


I think I'm downloading again...


Michael

Last edited by mige0; 10th January 2010 at 10:04 AM.
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Old 10th January 2010, 04:46 PM   #2263
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Originally Posted by mige0 View Post
Gary, I remember Lynn having mentioned elsewhere, that you did a output mod on the DCX with some hi-grade transformers by your own.

What I am specifically interested in is, if you've done some quality measurements of such transformers - simple harmonics would do here.

The reason I ask is that I never got around transformers to *not* add significant 3nd order at low frequencies - what I call the "iron sound" by myself.

Can this be overcome by selecting core material ?

You know, I don't wanna go into a discussion about perception of these 3rd harmonics just want to know what possibly is "common"

So, what realistically to expect in this regard form much smaller signal level - types ?

Michael
What you have measured seems to be pretty characteristic of the transformers I've measured in the past. I don't have data saved to present though. I've just made a quick trip to the lab to check an idea that's been rolling around in the back of my mind for a couple of weeks. The idea was to try using the Arta STEPS program to test transformers. Seems to work pretty well. Gives frequency response and harmonic distortion information on one graph. I'm willing to measure the transformers I have on hand to provide information on how the various transformers perform. I've got some Lundahl, Sowter, O-Netics, and a Slagle in a mix of core types.

Here is the measurement of a Lundahl LL1635 at 2.68Vrms voltage and 300 ohm source impedance.

Click the image to open in full size.

Things that would need to be finalized before running through the transformers would be:

Voltage level(s) of test
Impedance driving the transformers
Placement frequency for the cursor (determines what the set of data at the bottom of the graph presents)
Size of graph (This one is 800x600) Can be 1024x768
?

A baseline run of the measurement system would be included.

Do you find the information presented in the graph usable? The colors are hard to tell apart, but the way each line ends at the right side of the graph makes it easier to pick out which line is what harmonic, I.E. the blue line that extends the furthest is D2.

Gary
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Old 10th January 2010, 04:46 PM   #2264
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Originally Posted by mige0 View Post
Is the "Intermodulation Distorion" plot - where the 3rd order harmonics I mentioned (plus a whole bunch of odd order harmonics) can be seen as well - calibrated in dBu or dBV ?

Michael
Hi Michael, do not know what to tell you. RMAA software doesn't provide calibration like some others do. There is no calibration process where you measure voltage at the output or input and than enter that value in the software prefs. How it does reading is that ask you to provide signal that is close to clipping and than it takes that as 0 dB. There is not much control in that software. And I do not exactly know what Fqs are used for "Intermodulation Distortion" Have to check that if it it shows. I still have to do measurement at 1:2 setting which is better than 1:4. Let me know what do you want me to measure and I will do it on HP network analyzer.
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Old 10th January 2010, 08:16 PM   #2265
mige0 is offline mige0  Austria
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Originally Posted by Gary P View Post
I'm willing to measure the transformers I have on hand to provide information on how the various transformers perform. I've got some Lundahl, Sowter, O-Netics, and a Slagle in a mix of core types.

Gary
I'd be highly interested ! – I guess your offer would be gorgeous not only for me but also provide valid data in the context of that very thread.


Quote:
Originally Posted by Gary P View Post
What you have measured seems to be pretty characteristic of the transformers I've measured in the past.
...
Do you find the information presented in the graph usable?
Gary
Thanks a lot for all the effort - color scheme and information content is fine for me - also stimulus level and source impedance – all makes sense only for comparison anyway.

Bottom line of your plots show that 3rd order dominates by far the overall picture of that Lundahl transformer - almost not to distinguish from THD at frequencies < 1kHz (2nd order takes over past ~ 1kHz or so).
Second interesting fact I was not aware of is, that there seems to be a distinct frequency of lowest distortion at ~ 4kHz in this case.

What interests me most is, if substantially (> 10-20dB) different performance can be awaited from different makes - what you think?


Michael

Last edited by mige0; 10th January 2010 at 08:28 PM.
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Old 10th January 2010, 08:20 PM   #2266
mige0 is offline mige0  Austria
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Originally Posted by AR2 View Post
Hi Michael, do not know what to tell you..
What signal voltage you think was it right before clipping?
Basically we already can compare to Gary's measurements - plus/ minus - seems to me (for now) that saturation is not only an issue in the < 100Hz department - depending on expectations...


Michael

Last edited by mige0; 10th January 2010 at 08:25 PM.
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Old 10th January 2010, 08:27 PM   #2267
Zen Mod is offline Zen Mod  Serbia
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............!
AR2 - we connected them as 1:8
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Old 10th January 2010, 08:46 PM   #2268
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AR2 - we connected them as 1:8
Well, what I meant was this: 1+1 : 4+4
and 1+1 : 2 + 2
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Old 10th January 2010, 08:52 PM   #2269
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Well, what I meant was this: 1+1 : 4+4
and 1+1 : 2 + 2
sorry - maybe I didn't read your post good enough ......

I just wrote that we finally connected them as 1 parallel to 1 :4+4 , meaning 1:8
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Old 10th January 2010, 09:25 PM   #2270
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Hi Zen Mod - can't open pictures of your home page - any advice?

All that old cinema stuff - sounds interesting !

Michael
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