Thank you all for some very good comments and inputs!
Much appreciated!!
Yes, i am quite sure i can improve the conditions inside of my workshop. Groundplane measurements seems impossible in the area i live in.
I have ben hesitating a bit to do outdoor measurements, as i dont understand wind noise, background noise etc. are not having a major impact on the measurements.
Great input Turbowatch2>> I will continue experimenting to get a sense of the accoustic conditions in the room. I will definitely also try outdoors per your recommendation then. I have a gearbox lift that is a long thin cylinder, that can lift 1.7m - i can make it host a speaker in the top if i make an adaptorplate for it.
Azrael>> My intention is to develop loudspeakers myself, i have some past experience from my time at university, but only limited hands on - and never measured outside of an arachnoid chamber with B&K and Clio equipment 🙂
Can you explain in a bit more detail what you mean about timing reference issue with my microphone? I use UMIK-1 calibrated, then a Focusrite 2i2 audio interface, and the output is connected to a small amp, to drive the speaker.
Much appreciated!!
Yes, i am quite sure i can improve the conditions inside of my workshop. Groundplane measurements seems impossible in the area i live in.
I have ben hesitating a bit to do outdoor measurements, as i dont understand wind noise, background noise etc. are not having a major impact on the measurements.
Great input Turbowatch2>> I will continue experimenting to get a sense of the accoustic conditions in the room. I will definitely also try outdoors per your recommendation then. I have a gearbox lift that is a long thin cylinder, that can lift 1.7m - i can make it host a speaker in the top if i make an adaptorplate for it.
Azrael>> My intention is to develop loudspeakers myself, i have some past experience from my time at university, but only limited hands on - and never measured outside of an arachnoid chamber with B&K and Clio equipment 🙂
Can you explain in a bit more detail what you mean about timing reference issue with my microphone? I use UMIK-1 calibrated, then a Focusrite 2i2 audio interface, and the output is connected to a small amp, to drive the speaker.
By not using a timing reference VituixCAD is not able to predict the behaviour especially around the crossover points correctly. Getting good results would be a try-and-error-mission.
That might be not a big problem when using DSP-based active crossovers. But if you want to use passive crossovers you will be thankful to have this feature.
A timing reference ensures that the time correlations between the drivers of a multi-way system is also recorded, so if VituixCAD predicts two drivers being in phase, they will also in phase in the real world.
It can be created electrically with an XLR microphone on a two-channel audio interface (loopback connection)
Using REW an acoustic time reference would be possible with a USB microphone, but this method is more prone to errors. For that a second playback channel is required which powers a little speaker (a tweeter would be enough). This little speaker must not change it's position relative to the DUT during the entire measuring procedure.
Btw.: do you know this document?:
Measurements with Room EQ Wizard (REW) for crossover simulation with VituixCAD 2
That might be not a big problem when using DSP-based active crossovers. But if you want to use passive crossovers you will be thankful to have this feature.
A timing reference ensures that the time correlations between the drivers of a multi-way system is also recorded, so if VituixCAD predicts two drivers being in phase, they will also in phase in the real world.
It can be created electrically with an XLR microphone on a two-channel audio interface (loopback connection)
Using REW an acoustic time reference would be possible with a USB microphone, but this method is more prone to errors. For that a second playback channel is required which powers a little speaker (a tweeter would be enough). This little speaker must not change it's position relative to the DUT during the entire measuring procedure.
Btw.: do you know this document?:
Measurements with Room EQ Wizard (REW) for crossover simulation with VituixCAD 2
Thanks for sharing Azrael. I am planning to do passive crossovers. I just bought Vanace Dickinson’s Cookbook edition 8, and have the theoretical knowledge from my classes at university.
I didn’t know that document you linked to. That loopback connection is detailed quite well.
So if i understand it correctly, it is not enough for me to create a loopback from output of my Focusrite 2i2 to the input, when using my USB UMIK-1 mic?
It seems like i have to invest in a microphone for the mic input of the Focusrite 2i2 - What measurement microphone is best on a budget?
BR
Thomas
I didn’t know that document you linked to. That loopback connection is detailed quite well.
So if i understand it correctly, it is not enough for me to create a loopback from output of my Focusrite 2i2 to the input, when using my USB UMIK-1 mic?
It seems like i have to invest in a microphone for the mic input of the Focusrite 2i2 - What measurement microphone is best on a budget?
BR
Thomas
No, the mic has to be connected to the same audio interface that is playing back the test signal.
You did not waste money imo. I have different microphones for different tasks. An USB mike is fine for quick measurements, outside or in a car.
I got them XLR phantom powered, direct plug in (into the MIC in of a laptop) and a Dayton Audio for Android phones and use all of them occasionaly.
Setting up the whole rig with my 2i2, stand and the measuring amp needs time and room, so these quick solutions, even as they are not scientifically perfect, can be an option. For what you do at the beginning, your USB is just fine. If you buy a second microphone, get something factory calibrated. It is interesting to compare your mikes, if the calibrated ones match, you may get the 3rd without and check it against them. I'm no big friend of uncertified 2nd party calibration, I trust for example Sonarworks a little more.
Even the cheapest 28€ Behringer should/ can be quite linear, at least in the typical frequency range relevant for speaker building. They usualy fail sub 100Hz and above 6kHz. So the main region will be correct. The low end is usually known from simulations and too much room dependend anyway, getting the highest end right should be something you should carefully check by your ears and personal taste anyway. The region where something like "air" is relevant.
With active speakers things might look a little different... but that's another story.
I got them XLR phantom powered, direct plug in (into the MIC in of a laptop) and a Dayton Audio for Android phones and use all of them occasionaly.
Setting up the whole rig with my 2i2, stand and the measuring amp needs time and room, so these quick solutions, even as they are not scientifically perfect, can be an option. For what you do at the beginning, your USB is just fine. If you buy a second microphone, get something factory calibrated. It is interesting to compare your mikes, if the calibrated ones match, you may get the 3rd without and check it against them. I'm no big friend of uncertified 2nd party calibration, I trust for example Sonarworks a little more.
Even the cheapest 28€ Behringer should/ can be quite linear, at least in the typical frequency range relevant for speaker building. They usualy fail sub 100Hz and above 6kHz. So the main region will be correct. The low end is usually known from simulations and too much room dependend anyway, getting the highest end right should be something you should carefully check by your ears and personal taste anyway. The region where something like "air" is relevant.
With active speakers things might look a little different... but that's another story.
No-one has mentioned wasting money: of course there are applications where a USB mic can be useful. And yes: if necessary, you can also use an acoustic time reference with such a microphone.
But if I want reliable predictions from VituixCAD, then my desire for improvisation is rather less pronounced.
But if I want reliable predictions from VituixCAD, then my desire for improvisation is rather less pronounced.
Yes your phone does a real time FFT split into 16 bands.
The mic input on my realistic 31 8000 equalizer is also capable. This is the model with LED graphic display switchable to 2db steps with built in noise generator.
There is also a turntable speed and wow / flutter measurement app.
The mic input on my realistic 31 8000 equalizer is also capable. This is the model with LED graphic display switchable to 2db steps with built in noise generator.
There is also a turntable speed and wow / flutter measurement app.
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