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Viper_user 16th August 2012 10:14 AM

Help with calibration
 
Hi!
I use an active system on passive speakers.
This is the speakers. ~1000$
http://web.comhem.se/~u73702837/Active/IMG_6565.JPG



The blue is the original passive filter i want to came close to. (don't mind the brown line.)
The mic also, is an cardioid and is not flat in it's response.
http://web.comhem.se/~u73702837/Active/Range.jpg


This is my latest setup now with active filter and two amps, It sounds really good
but i wonder about the response. According to Lindqvist railey it should be increasing sum. Link
http://web.comhem.se/~u73702837/Active/22.jpg
http://web.comhem.se/~u73702837/Active/panel.jpg


I have also put some delay on the tweeter (measure). to put it on the same coil distance.
http://web.comhem.se/~u73702837/Active/delay.jpg

And this is the miracle box :)
http://web.comhem.se/~u73702837/Active/led.jpg



Any hints for me? this is my first active setup.
Cheers!

VA2GXB 16th August 2012 01:01 PM

A key is to have the mic calibrated. I know it seems tiny, but Panasonic's WM61-A is used in many places as a measurement mic, and calibration files are readily available - check the response

http://img812.imageshack.us/img812/6121/soundcard.png

vacuphile 16th August 2012 01:11 PM

What you see is an interference dip around xover because of phase misalignment and that is why it doesn't sum properly. Play with the delay until it sums flat.

Viper_user 18th August 2012 06:49 PM

Quote:

Originally Posted by vacuphile (Post 3128545)
What you see is an interference dip around xover because of phase misalignment and that is why it doesn't sum properly. Play with the delay until it sums flat.

In fact 0,13ms is the setting i got from measure with mic.
The two drivers appear like just one when put on this delay
It its strange that the delay function give this measurment.

Viper_user 18th August 2012 07:03 PM

Ahha now I have tried to measure with a dynamic microphone. A classic SM57.
And now I got one more expected response, so there was no problem with phase cancellation


http://web.comhem.se/~u73702837/Active/measure3.jpg

vacuphile 18th August 2012 07:05 PM

Quote:

Originally Posted by Viper_user (Post 3131518)
In fact 0,13ms is the setting i got from measure with mic.
The two drivers appear like just one when put on this delay
It its strange that the delay function give this measurment.

I suggest reversing the phase on the tweeter make a new measurement. It will probably still not be good, but better. Just play around with the delay until it is straight.

The only other possibility is that you have a gap beteen the low pass and the high pass, but with a DSP and common sense that is unlikely,


vac

Viper_user 18th August 2012 07:14 PM

And now to the interesting point. The difference from these speakers between the passive filter and active.

The sound is now very fixed and instruments are more placed in the image.
It was kind of diffusely before. A bit like you have turned on the light now. :)

It would be interesting to try this out on a couple of finer drivers some time.
Cheers!

Viper_user 18th August 2012 07:20 PM

Quote:

Originally Posted by vacuphile (Post 3131533)
I suggest reversing the phase on the tweeter make a new measurement. It will probably still not be good, but better. Just play around with the delay until it is straight.

The only other possibility is that you have a gap beteen the low pass and the high pass, but with a DSP and common sense that is unlikely,


vac

It was the human factor.:D My old measurment was not reliable

Viper_user 18th August 2012 07:28 PM

And now the Phase when measure with a dynamic mic. (the lower line)


http://web.comhem.se/~u73702837/Active/phase2.jpg


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