After a lot of conversation, doubts resolved and tips given about capacitors in an old post I made (https://www.diyaudio.com/community/threads/crossover-the-infamous-capacitors.414191/), I noticed that there was no way out other than taking measurements of my speakers with a microphone instead of already building a crossover using an online calculator (The That doesn't take away from the fact that these calculators help me a lot to get an idea of how it works and I'll spend more or less on it and because of that I owe all my thanks to my hobby friend @Galu ).
I was recommended to use the Umik-1 microphone which in my country would literally cost 3 times more than buying it abroad (±150 dollars) plus the fee to bring in 95% of the price of the product plus shipping (sadness). In the end it would cost around ±300 dollars.
@geotone showed me that I could build a precision microphone that would be able to measure my speakers using a cheap microphone from aliexpress (as an example) whose link is this: https://pt.aliexpress.com/item/1005004281678104 .html?gatewayAdapt=glo2bra
And complementing @geotone, the user @ulogon recommended me a very interesting article on how to build one at home for measurements, the link to the article is this: https://www.diyaudioandvideo.com/Tutorial/BuildMicrophoneForSpeakerTesting/
Using these sources I plan to build the microphone but first I have some doubts such as:
What should the room be like for speaker measurements?
Should I measure the speaker without the box and then with the box? (That means I'll have to build the box first).
How should measurements be taken so that everything goes well?
After the measurements, what would be the next big steps?
Another question about crossovers now is that I was choosing speakers with only 4ohms, I would like to know if I can buy 8ohm speakers and mix them?
For example, a 4ohm tweeter, a 4ohm midrange and an 8ohm woofer, do the crossover and connect them to a 4ohm amplifier.
I was recommended to use the Umik-1 microphone which in my country would literally cost 3 times more than buying it abroad (±150 dollars) plus the fee to bring in 95% of the price of the product plus shipping (sadness). In the end it would cost around ±300 dollars.
@geotone showed me that I could build a precision microphone that would be able to measure my speakers using a cheap microphone from aliexpress (as an example) whose link is this: https://pt.aliexpress.com/item/1005004281678104 .html?gatewayAdapt=glo2bra
And complementing @geotone, the user @ulogon recommended me a very interesting article on how to build one at home for measurements, the link to the article is this: https://www.diyaudioandvideo.com/Tutorial/BuildMicrophoneForSpeakerTesting/
Using these sources I plan to build the microphone but first I have some doubts such as:
What should the room be like for speaker measurements?
Should I measure the speaker without the box and then with the box? (That means I'll have to build the box first).
How should measurements be taken so that everything goes well?
After the measurements, what would be the next big steps?
Another question about crossovers now is that I was choosing speakers with only 4ohms, I would like to know if I can buy 8ohm speakers and mix them?
For example, a 4ohm tweeter, a 4ohm midrange and an 8ohm woofer, do the crossover and connect them to a 4ohm amplifier.
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Given that I'm able to only answer this question
, I think I understand that the microphone must be very directional to minimize the effects of the room on the measurements.And its directionality can be increased by placing it in a tube (shotgun microphone).
It is also better for the microphone to have high sensitivity and a high signal-to-noise ratio.
Positive side is that it seems that microphones suitable for this purpose cost little, at least in these parts.
As large as possible with the speaker/microphone group centered in all dimensions of the room. In practice, gating/windowing of the signal will be necessary to eliminate sound reflections from room surfaces. This is quasi-anechoic measurement. You should read about it thoroughly. Basics are discussed here: https://www.stereophile.com/features/103/index.html
Outdoor measurements are another possibility if you don't mind dragging all your equipment outside, if it's quiet where you live, if you don't have neighbors that will get annoyed with it, etc., etc.
For a funny extreme example of room size, an old power plant building is handy
https://www.stereophile.com/content/nwaa-labs-measurement-beyond-atomic-level-page-2
"NWAA's free-field room is the size of four football fields—so large that there's no need to gate impulse-response measurements."
Assuming you are going to use them in a normal sealed/ported design, measuring speakers without the box is typically only done if you want to check free-air Thiele Small parameters or if you are investigating basic behavior for a specific reason. The box makes multiple changes to how the speaker behaves, so from a design standpoint, you need it in the measurements for accuracy.
I have ugly test boxes I use over and over for early prototypes and basic measurements.
Carefully, and after you understand the basics. It's very, very easy to introduce errors that show more about the measurement technique than the speaker performance.
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Forget the above question for now and concentrate on microphones & measurement.
Asking an additional question which is not directly associated simply serves to complicate the issue.
P.S. My knowledge of microphones & measurement is scant, my friend, but I'll continue to follow the thread with interest!
There are books and manuals, even videos that teach you how to measure right. You could start here https://audioxpress.com/assets/upload/files/dappolito2959.pdf
And here: https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_help_20.html
And here: https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_help_20.html
Do you actually want to build something or do you want to keep yourself busy with irrelevant fears? I'll rejoin when I see pictures of your progress.
You have all the information you need available, Vituixcad help is a great start. Confused questioning only yields confused answers. Read up first.
You have all the information you need available, Vituixcad help is a great start. Confused questioning only yields confused answers. Read up first.
I think part of the issue is the overload any new builder is likely to face when the internet is the primary source of information. There are a lot of random, tweaky ideas that get discussed and it's hard to separate big ideas from small ones when it's all new information. It's the old drinking from the fire hose problem.
An organized, well respected book is still a good place to start. The Loudspeaker Design Cookbook by Dickason has been that source for a long time for good reason. It doesn't cover everything, but it's solid and isn't full of edge case ideas.
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Given that I'm able to only answer this question
And its directionality can be increased by placing it in a tube (shotgun microphone).
It is also better for the microphone to have high sensitivity and a high signal-to-noise ratio.
Positive side is that it seems that microphones suitable for this purpose cost little, at least in these parts.
Sorry but this advice about directional microphone is the worst you can give for measurements.
Directional microphone are built using figure of 8 pattern capsule and as such are subject to what is known as proximity effect. In practice this give a rise of low end ( varying with distance).
Frequency response of such microphone will vary a lot too if not on axis so forget about this.
Measurements microphone are all omni. And 99% of them small capsule type ( 6mm -1/4").
Usb microphone seems handy but it comes to a price: you can't make phase measurements with them ( because usb protocol is asynchroneous and as such you can't make two chanels measurements technique which allow to define phase).
So if you want to make serious measurements you'll need:
A small capsule measurement mic and a 2 chanel audio interface ( something like Focusrite Scarlett whicjh include mic preamp and two chanel in/out to perform a loopback for one out to one input to have a synchronised signal to compare your mic to and then have an absolute reference to extract phase).
It's probably not what you would like to hear but truth it is.
For the mic no need to go crazy: Dayton emmc6 or a Behringer ecm800 derivative is more than enough even for advanced designers to have meaningful data. Better mic offers higher spl capability, lower and higher freq range, lower inner noisefloor, better calibration and qualty control but in a typical room
It won't make a difference.
I would not go into the rabbit hole of designing your own mic either. At least not at first: the good small capsule that were availlable twenty years ago are now scarce and you wouldn't have calibration files easily availlable ( Dayton offer them with their mics).
Don't take me wrong, designing microphone is fun and something i do but not for measurement duty and it ask to master electronic a bit. It have some very specific issue too ( capsule are very high impedance and everything must be clean as hell as a fingerprint can make all bass disappear...).
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For the record, the 8th Edition of the Loudspeaker Design Cookbook (LDC) has a new Chapter 9: “Computer Based Tools for Loudspeaker Development” has been completely revised to include current offerings of computer-based loudspeaker measurement analyzers, as well as loudspeaker enclosure and crossover simulation software.
@Pedroga Past editions of the LDC have been available in Brazilian Portuguese.
I had just purchased the Panasonic WM-61A, should I refund it?
I had plans to use a 2.2kΩ or 10kΩ resistor and a 10µF capacitor
Therefore, it will be better for me to do the crossover without the measurements.
@Galu I was just starting to read this book. I will complete it and make notes of everything I can for this book.
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I don't know this capsule so can't say if you must refund it or not.
I'm not in your situation so can't tell what to do.
Important points have been given to you to see if it's worth investing in the gear presented or not.
If you think this hobby will last on you then you'll invest in gear presented at one point or another because of limitations you'll encounter.
If your initial plan is just to build something and have fun then go ahead and have fun! Thats the whole point.
And... we all spent money on things we did not used or wasn't on par with what we expected. It's part of this hobby. Sad but it's the way it is.
Our fail make us progress, whatever they are.
I'm not in your situation so can't tell what to do.
Important points have been given to you to see if it's worth investing in the gear presented or not.
If you think this hobby will last on you then you'll invest in gear presented at one point or another because of limitations you'll encounter.
If your initial plan is just to build something and have fun then go ahead and have fun! Thats the whole point.
And... we all spent money on things we did not used or wasn't on par with what we expected. It's part of this hobby. Sad but it's the way it is.
Our fail make us progress, whatever they are.
the same recommendation you gave, chatgpt said the sameI don't know this capsule so can't say if you must refund it or not.
I'm not in your situation so can't tell what to do.
Important points have been given to you to see if it's worth investing in the gear presented or not.
If you think this hobby will last on you then you'll invest in gear presented at one point or another because of limitations you'll encounter.
If your initial plan is just to build something and have fun then go ahead and have fun! Thats the whole point.
And... we all spent money on things we did not used or wasn't on par with what we expected. It's part of this hobby. Sad but it's the way it is.
Our fail make us progress, whatever they are.
It's an electret so should incorporate a preamp making it less sensible ( preamp have lower output z).
Buy some isopropyl alcool ( 99.9%) to clean flux and solder residue and work with nitril gloves, it should do.
Holly sh.t! Are you comparing me to a soul less bot?!
Time to comit suicide... LOL!
Please give my 15years as member here some credit and don't ever compare me again to a brainless bot my friend. Lol.
Buy some isopropyl alcool ( 99.9%) to clean flux and solder residue and work with nitril gloves, it should do.
Holly sh.t! Are you comparing me to a soul less bot?!
Time to comit suicide... LOL!
Please give my 15years as member here some credit and don't ever compare me again to a brainless bot my friend. Lol.
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If this is a genuine WM-61A, you have a treasure beyond price as these were the most reliable and consistent 6mm electret capsules. They were used in Measurement Mikes from early Behringer ECM 8000s to $$$ Earthworks.
audioimprov.com/AudioImprov/Mics/Entries/2017/12/13_A_Simple_Reference_Mic.html
shows how to make a P48 version which will almost certainly be flatter than an ECM 8000.
The theory behind it is at https://groups.io/g/MicBuilders/files/Ricardo/SimpleP48
You have to join.
If you don't have p48V phantom power, you can do this but you need a mechanical arrangement similar to Henry's XLR so you can hold it in a microphone clip & stand. But the P48 version has MUCH better performance.
krivium, no problem, I know your feelings and instead thanks for your informative post and sorry if I was so wrong in reporting part of what I thought I understood from reading the content of that article since I read those informations from the following website that I've linked in a different and similar thread of the same OP.
However, just to reiterate that I had pointed out my lack of expertise in that matter please note I said
(it was implicit: "reading the article I linked") giving credit to a site where generally correct things are written.
So, sorry if no credit on my part for providing the link to that website and for reporting in good faith part of my understanding about the related article and not too demerit maybe for giving credit to a site and an article that actually didn't seem to deserve it anymore, as you instead were able to positively criticize.
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