Recent content by No. 5

NanoCAD has a free option and it's 2D, the user experience is very close to AutoCAD. If you are familiar with SolidWorks, they have very cheap prices for single user, non commercial use, if you contact a reseller. OnShape is 3D and has a free option and has almost no learning curve if you...

I'm sorry, but I'm not following how that's connected to knowing the absolute SPL of a measurement, could you explain? I mean, a virtual bass array is still cool and all...

Thank you for explaining your position, I see what you are talking about in regard to providing a reference point. I'm going to risk being called pedantic now, and propose that you did actually measure the noise floor. :) Consider this waterfall: This is a measurement sweep (sort of), level...

I think I understand what you are saying, but looking at it another way, isn't the difference between the system/room noise floor and the measurement level always relative? I mean, if you know the measurement level is truly 75dB and it decays into noise at 35dB, how is that different from seeing...

That would be an example where knowing the true SPL isn't necessary. Consider that an offending mode will present itself in two ways: as narrow band of frequencies that are higher than the "average" level, or as prolonged ringing around a narrow band of frequencies. To identify a mode in the...

If you are doing a measurement where true SPL is relevant (and it's not for many), you need to decide how "true" you want it to be. If you want it to be within 2dB and around $30, I'd say find yourself a used Quest acoustic calibrator or a used Extech, Sper Scientific, or Quest class 2 sound...

Well, you will get something. The mic capsule and preamp have self noise, as does everything else up the capture chain in addition to ambient background noise. However, your time scale is set to two full seconds, and whatever it is looses almost no energy over that time (it probably disappears...

Its low frequency roll-off is unknown. In other words, it is accurately measuring frequencies but not the SPL of those frequency. Therefore I would not recommend using it for a house curve. But for getting a look at what's happening at low frequency it is still a very useful tool because it will...

I do, it's in my thread 'near field scanner on a shoestring' over at DIYAudio. It's probably still best to splice in a ground plane measurement below 200Hz or so, but it has the potential to get far more detail below 1kHz than what can be typically achieved with an IR window.

I am also a bit surprised by how close the structure is to the microphone. I know they are using sound field separation up to 1.5kHz, but you'd think you'd want enough breathing room around the mic to allow a 3 millisecond (or so) IR window... but maybe there is enough breathing room or they're...

Can do! Just had to find it again... I'm not great at documentation... This is one of the three Behringer B2030P's that I have and measured via beamforming compared to the Klippel data from the ASR reviewed B2030P. Top to bottom is Klippel NFS; beamforming 41 points vector averaged...

Short answer: it should remove it. Long answer: I believe that sound field separation works the same as a sound intensity measurement in that the system is aware of the arrival vector of any sound passing through the bounding measurement surfaces and can consequently ignore anything coming from...

That sounds like a reasonable trade off to me, and gives me something to think about for my own project. "Seeing" clearly between 100Hz and 1kHz is, as you well know, not easily doable for a DIY'er, and having a way to do that is by itself a massive advantage and was one of the big driving...

Another useful method in my opinion! I've been impressed what you have been doing with the beamforming technique (I go by aslepekis over at DIYaudio). :)

Evaluating that seems worthwhile to me, as getting a full radiation balloon at high frequencies seems useful. That being said, having sound field separation and any kind of 3D look at the radiation pattern is a huge advancement, so having some holes in the coverage at angles that aren't...