I just installed HOLMImpulse, compared to SW it is far away better and more user friendly. I use a diy microphone with a WM61A capsule.
I measured a Cyburgs Needle with a FRS8 driver at a distance of 0.5m. I added the calibration file for the WM61 but the response is very weird. There is a steep roll off starting at 5Khz. Would you advice what causes this problem, the program says my setup is fine. Card is uncalibrated ( line out --> line in ).
I measured a Cyburgs Needle with a FRS8 driver at a distance of 0.5m. I added the calibration file for the WM61 but the response is very weird. There is a steep roll off starting at 5Khz. Would you advice what causes this problem, the program says my setup is fine. Card is uncalibrated ( line out --> line in ).
An externally hosted image should be here but it was not working when we last tested it.
Can someone help me with HOLMImpulse and step response (it may already have been addressed- sorry).
I have a digital active 3-way system.
I can adjust the delay in many ways, including distance measurement, or better still, using Praxis to get the optimum step response.
But I haven't had success with HOLMImpulse.
What I have done is add delay for each driver so that the separate impulse peaks overlay the stimulus peak (zoomed in for accuracy).
Is this logic correct? It certainly measures differently this way, and doesn't sound right.
With thanks.
David
I have a digital active 3-way system.
I can adjust the delay in many ways, including distance measurement, or better still, using Praxis to get the optimum step response.
But I haven't had success with HOLMImpulse.
What I have done is add delay for each driver so that the separate impulse peaks overlay the stimulus peak (zoomed in for accuracy).
Is this logic correct? It certainly measures differently this way, and doesn't sound right.
With thanks.
David
Hmm.. this is strange..
Tried to calibrate the sound-card on my lap-top using the loop-back function..
After having done the calibration sweep, the measurement is implemented, and i get a new sweep curve showing perfectly flat frequency and flat Phase response..
But when I do a new sweep (ordinary measurement this time) through the same loop, the phase is not flat anymore!
Have i missed something obvious here??
Best regards,
Tried to calibrate the sound-card on my lap-top using the loop-back function..
After having done the calibration sweep, the measurement is implemented, and i get a new sweep curve showing perfectly flat frequency and flat Phase response..
But when I do a new sweep (ordinary measurement this time) through the same loop, the phase is not flat anymore!
Have i missed something obvious here??
Best regards,
Here's the plot from the calibration run i attempted.. Blue is the loop-back measurement, red is the corrected response (?), and green is the measurement I did last with the loop still connected..
Don't know if anybody can read anything from this.. I was expecting the green curves to be exactly like the red ones??
Don't know if anybody can read anything from this.. I was expecting the green curves to be exactly like the red ones??
Attachments
Well, I've only found one check-box for ADC-DAC converter, and that's the one under the device & Signal tab where you can allso initiate the calibration or import a calibration file.
When I un-tick this box and perform a new measurement, it is obvious that the measurement is not corrected with calibration.
Also, when I run the measurement, it says that calibration is being applied in that window that pops up.
What else could be wrong here??
Would really hate not to have this sorted by the time I have my measurement mic buildt!!
When I un-tick this box and perform a new measurement, it is obvious that the measurement is not corrected with calibration.
Also, when I run the measurement, it says that calibration is being applied in that window that pops up.
What else could be wrong here??
Would really hate not to have this sorted by the time I have my measurement mic buildt!!
Well, My default was set to MME, and uppon switching to ASIO, the in and output windows went blank, hence it was obvious I missed that ASIO driver, whatever that might be!
Anyway, followed your advice, downloaded and installed, and voila; both frequency response and phase was flat as a pancake!
Seems THD went up a bit, but perhaps this is due to my set-up? I looped the headphone-output (only analog audio out available) straight in to the mic-input pulling output level allmost to the bottom to avoid digital clipping..
Perhaps the digitally limited( i assume) output gives high THD or noise and I'd be better off attenuating with some resistors?
Anyway, thanks a lot for the advice, couldn't have figured this one out my self!
Anyway, followed your advice, downloaded and installed, and voila; both frequency response and phase was flat as a pancake!
Seems THD went up a bit, but perhaps this is due to my set-up? I looped the headphone-output (only analog audio out available) straight in to the mic-input pulling output level allmost to the bottom to avoid digital clipping..
Perhaps the digitally limited( i assume) output gives high THD or noise and I'd be better off attenuating with some resistors?
Anyway, thanks a lot for the advice, couldn't have figured this one out my self!
You bet I was glad it wasn't something more serious!!
For all I know, it could have been some inherent feature in the hardware which couldn't be fixed, after all, this little ASUS Eee laptop is a dirt cheap simple little thing not intended for any "serious" use!
And now I can do stuff with it that would otherwise require a rig of measurement equipment. amazing!
No, I don't use any digital out or anything, sort of gathered one can buy nice external ADC-DAC units that run through the USB, but for my use I don't really see the point as I really don't need perfect THD or noise performance as long as I can do decent frequency and phase on some DIY speaker projects!
See if I can dig out some resistors and hook up a voltage divider so I can run the output at higher level just to see if that will improve distortion.
Once again thank you very much!!
For all I know, it could have been some inherent feature in the hardware which couldn't be fixed, after all, this little ASUS Eee laptop is a dirt cheap simple little thing not intended for any "serious" use!
And now I can do stuff with it that would otherwise require a rig of measurement equipment. amazing!
No, I don't use any digital out or anything, sort of gathered one can buy nice external ADC-DAC units that run through the USB, but for my use I don't really see the point as I really don't need perfect THD or noise performance as long as I can do decent frequency and phase on some DIY speaker projects!
See if I can dig out some resistors and hook up a voltage divider so I can run the output at higher level just to see if that will improve distortion.
Once again thank you very much!!
That's good that it worked out for you. If you want to explore the capabilities of the card a little further I recommend using Right Mark Audio Analyzer. It should give you an idea of what your card can and can't do as well as measuring which settings will work best with that specific card.
Wow.. the advice keeps flowing in here!
Much appreciated though, because I'm getting some strange results..
Messed about a bit with a few resistors and pulling input/ output gain up and down to balance.
the THD curve changed several times (not only in overall magnitude), and suddenly a weird narrow "spike" appeared in the phase plot. Almost like something isn't behaving entirely consistent or stable..
Perhaps there is some DC messing things up? Better get a proper pot and a cap and do some more systematical measurements in order to see if there is some pattern to this.
That Mark audio analyser sounds interresting.. must check that out!
Thanks again!
Much appreciated though, because I'm getting some strange results..
Messed about a bit with a few resistors and pulling input/ output gain up and down to balance.
the THD curve changed several times (not only in overall magnitude), and suddenly a weird narrow "spike" appeared in the phase plot. Almost like something isn't behaving entirely consistent or stable..
Perhaps there is some DC messing things up? Better get a proper pot and a cap and do some more systematical measurements in order to see if there is some pattern to this.
That Mark audio analyser sounds interresting.. must check that out!
Thanks again!
