Recent content by jesperlykke

Nice you figured it out! But you should really create your'e own calibration file, to be sure that the notch is up to date allway's. I also create different compensation file's depending on the ADC's input level (could be 1.7V or 4.5V), also if the notch have some 0dB and +6dB setting, I have a...

Hi johny... Please read my other thread regarding the use of an compensation curve https://www.avnirvana.com/threads/measuring-freq-response-with-a-deep-notch-cannot-measure-the-correct-depth.11825/

Hi Johny... Yes you should use both external notchfilter + the AES17 notch. The AES17 is to take care of the sinewave's "skirt" Jesper.

I see... thanks... So A is just a calculation i see, makes good sense. Will dig some more into this next few days :) Jesper.

So after some time, I stumbled upon the (A)weighted measurement. I'm not aware of which kind of numbers I got using my calibration file as pr. instructed here in post #16 to #18. Or is it possible to change something and get (A) measurements or do I allready get that. I'm having problems...

I accept that, also that it's correct. So anything above my ADC's 0dbfs level (around 1.339v) will be shown as +dbfs I did know that, and I also realize that it's not making sense what I asked as an option for REW. Jesper.

Hi... A ran some test, to try the two different calibration techniques out. All test is with Victors 998Hz oscillator @ 2.1V sine. The Notch is the Cosmos APU adjusted to -41dB / 998Hz. I carefully calibrated the voltage levels in REW before I started the test's. I'am in no doubt, that I would...

This is really great... After some hour's with trial and error I finally got it right. (Notch is dual fliege OPA1662) This is the way I did it for the result's (see pictures for better explanation) : 1. Adjust Analysis. 2. Take measurement with notch and without notch. (-25dB - Full input...

Yes... this is excatly how I use my passive notch ----> My other thread regarding passive notch This methoed is working as expected. I will make some test, and compare them and post them here afterwards. Jesper.

Great... So you suggest me to try it out adjusted so that the TOP of the notch (away from the notch) is adjusted to 0 SPL instead? - Please see picture. Or should I do as I did with my passive notch the trace arithmetic (Notch response / No notch response (soundcard loopback) BTW. Is it...

Hi here... As I said, proberly need to have some more cleared out. I created a "mic. calibration" / notch compensation file, as Archimago do. Link ----> Archimago notch compensation (It's just to allign the measured notch SPL to 0 via. add offset in the SPL & Phase dialog + export measurement...

So this is solved now :) Allway's help John, thanks... Tried to do a couple of 4M / 48kHz sweep's... Notch is >70dB deep I will proberly ask some more quistions regarding the calibration file Jesper.

Will do for sure...

Perfect.... Thank's John.

Is it the Decimate IR checkbox. Sry. I'am not knowing that much about that YET :T