A member on another forum I frequent share this link with me for a network analyzer that could be used to measure speaker impedance: CircuitGear MKII – Syscomp Electronic Design
I was planning to use an old HP audio generator and do it the hard way, but that little scope/analyzer/etc, looked interesting, and a whole lot faster. My big concern is that it only has a 60dB range for the analyzer.
Are there recommendations for cheap DIY tools for measuring and graphing audio frequency sweeps that have a broader range? The thing making the above tool interesting is that it is good well into the MHZ range, which would be nice for working on old radios and such too.
computer and sound card seems an option, but I don't have a decent sound card that I would trust to give as high quality information as a dedicated piece of kit that plugged in via USB. I'm partial to antique gear, but I'm also liking automatic graphing functions and data collection.
I was planning to use an old HP audio generator and do it the hard way, but that little scope/analyzer/etc, looked interesting, and a whole lot faster. My big concern is that it only has a 60dB range for the analyzer.
Are there recommendations for cheap DIY tools for measuring and graphing audio frequency sweeps that have a broader range? The thing making the above tool interesting is that it is good well into the MHZ range, which would be nice for working on old radios and such too.
computer and sound card seems an option, but I don't have a decent sound card that I would trust to give as high quality information as a dedicated piece of kit that plugged in via USB. I'm partial to antique gear, but I'm also liking automatic graphing functions and data collection.
I’ve got to work on putting together a better computer for at home, Will look into a decent sound card at some point, but for now I’ve just got the crappy stuff that came with a dell tower. Hoping that I can find something not too pricey that sounds decent and has better output connectors than the little 3.5mm headphone connectors.
I ended up wanting a pico USB scope that was going to cost way too much money, and stumbled upon the syscomp circuitgear mini for about $40 delivered. It will cover audio spectrum easily, and seems to have pretty good software that comes with it. This thing should do what I want it to. Next job is to find a decent microphone for frequency response testing, and I should be good to go for now.
I ended up wanting a pico USB scope that was going to cost way too much money, and stumbled upon the syscomp circuitgear mini for about $40 delivered. It will cover audio spectrum easily, and seems to have pretty good software that comes with it. This thing should do what I want it to. Next job is to find a decent microphone for frequency response testing, and I should be good to go for now.
Lots of great DIY system tools by the great Dr Linkwitz.
System Test
Make your own mic with a $2 Panasonic capsule (same as what is used in a $100 mic) .
System Test
Make your own mic with a $2 Panasonic capsule (same as what is used in a $100 mic) .
Trust me, we have all been there. I also have a few of the $2 Panasonic mic’s with associated DIY Preamp circuit. It works but when you measure speakers as much as I do, you will come to appreciate a $100 tool that just works. No fuss.
But, it’s all part of the the diy journey - just give it time. Maybe you won’t measure that many speakers and it will be fine. I have designed and built at least 50 speakers and measured as many or more drivers. So, the convenience is key for me.
You can also use your phone and a $16 calibrated mic.
Dayton Audio iMM-6 Calibrated Measurement Microphone for Tablets iPhone iPad and Android
It won’t interface with REW though.
Or use a $50 calibrated 48V phantom power mic:
Dayton Audio EMM-6 Electret Measurement Microphone
But, it’s all part of the the diy journey - just give it time. Maybe you won’t measure that many speakers and it will be fine. I have designed and built at least 50 speakers and measured as many or more drivers. So, the convenience is key for me.
You can also use your phone and a $16 calibrated mic.
Dayton Audio iMM-6 Calibrated Measurement Microphone for Tablets iPhone iPad and Android
It won’t interface with REW though.
Or use a $50 calibrated 48V phantom power mic:
Dayton Audio EMM-6 Electret Measurement Microphone
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The oscilloscope will not give you nice frequency response measurement like a sound card and REW. Oscope is 8 bit resolution. REW has a lot of features like gating, different window functions, etc. it’s free and perhaps one of the best out there for diy speaker measurement.
There’s ARTA, Holmimpulse, etc. but I like REW best.
There’s ARTA, Holmimpulse, etc. but I like REW best.
This one is 11 bit resolution, supposed to be pretty decent. I will check out rew, but I don't have anything resembling a decent sound card at the moment, and my computer at home is rather ancient. Work calms down a bit after this week or next, so I won't be so tired after and will have more energy to devote to fun stuff in my free time. hopefully I can get everything closer to sorted by then.
I recommend ARTA, its documentation's contents might look daunting.
But once you understand them, you will realize what is the best practices, approach and basic math to calculate reflection on speaker measurements(For accurate gating).
They also had a method of measuring port freq response and using driver diameter with port diameter to calculate and scale the measurement accurately
But once you understand them, you will realize what is the best practices, approach and basic math to calculate reflection on speaker measurements(For accurate gating).
They also had a method of measuring port freq response and using driver diameter with port diameter to calculate and scale the measurement accurately
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Finally got the little circuitgear Mini working properly, did some bode plots of the various drivers in free air, didn’t save anything, though, and no pics... I did get to look at it making almost identical plots with two of the same model drivers, though, which was reassuring to see. I need a slightly less cumbersome method for hooking up the oscilloscope and generator along with the series resistor, so that everything has as few extra leads as possible, and can clip onto the drivers faster. Next job is to get my “calibrated” mic, or maybe even a properly calibrated one. For now, I’m down with having “good enough” in order to have a graphical record of what I’m hearing. It seems like for my purposes at the moment, being able to visually compare results will be more important than absolute accuracy.
Got some little mic capsules to test, but I still need a couple of short lengths of tubing in which to mount them. I've also got to buy a couple of op amps to use with them. I'm looking at this setup on the linkwitz page:
System Test
Is it best for making frequency response measurements using a separate mic preamp and the line level input on the sound card, or plug directly into the mic input? Also, on the mic input is there normally some voltage supplied internally to run condenser mics, or do you need to add this as done in the circuit above?
I know this won't be calibrated, but I've got a couple different modules to try out, and see where that gets me. would be easier to simply buy a calibrated mic, but this is DIY!
supposedly very flat frequency response from these JLI mic capsules. we'll see...
After putting these together, it's time to get the old computer my friend is giving me fired up, get REW installed, and start building some boxes.
System Test
Is it best for making frequency response measurements using a separate mic preamp and the line level input on the sound card, or plug directly into the mic input? Also, on the mic input is there normally some voltage supplied internally to run condenser mics, or do you need to add this as done in the circuit above?
I know this won't be calibrated, but I've got a couple different modules to try out, and see where that gets me. would be easier to simply buy a calibrated mic, but this is DIY!
supposedly very flat frequency response from these JLI mic capsules. we'll see...After putting these together, it's time to get the old computer my friend is giving me fired up, get REW installed, and start building some boxes.
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