Any form of measurement mic is going to put you in a way better position than flying blind. from 17 years ago, my first attempt at doing some measurements Speaker Workshop + Microphone = invaluable 🙂
Tony.
Tony.
Yes.
Just finding something cost effective and reliable with constant results is what I'm after.
Do you have a link to the thread by any chance? Google couldn't help and I'd be interested in looking at that.
Maybe I should have titled it in a better way - my apologies. Dumpster Diving, Yard Sale and Thrift Store Speaker Quick Assessor
As was said, this will put you in a lot better position than no mic / analyzer.
I'd say the (auto-magically uncompensated) phone based mic and the $15 analyzer app would put you 99% of the way there; if you need lab-grade, nist-traceable, absolute frequency band db SPL measurement values - that another person can reliably repeat using the same equipment elsewhere - sky's the limit on expenditure for attaining that.
As was said, this will put you in a lot better position than no mic / analyzer.
I'd say the (auto-magically uncompensated) phone based mic and the $15 analyzer app would put you 99% of the way there; if you need lab-grade, nist-traceable, absolute frequency band db SPL measurement values - that another person can reliably repeat using the same equipment elsewhere - sky's the limit on expenditure for attaining that.
I will look through that other thread in a bit but it has crossed my mind to go cheap and cheerful as you indicate. I've even contemplated the mega cheap mics on Amazon like these which plug into phones / tablets / PC as a better than nothing option.
Dayton Audio iMM-6 Calibrated Measurement Microphone for iPhone, iPad Tablet and Android: Amazon.co.uk: Musical Instruments
As you say it'll get you most of the way there even if its not the ultimate in accuracy, but how sharp do you really need it to be and most of all its not going to cost me a lot.
The phone app things looks ok but I don't think there's any substitute for having a proper line plot trend which are the most familiar when looking at frequency responses.
I am very tempted to go cheap 🙂
I have a dayton IMM-6 and definitely would recommend it. You will need a four pole to three pole adaptor to use it on a trs 3.5mm mic socket or to output to RCA.
The mic uses the second ring (furthest from tip) and sleeve connections. I purchased a four pole TRRS socket and just ran a shielded mic cable from the second R and sleeve connection to an RCA that I use with my dedicated mic pre. I'm not sure whether a 3.5mm mic input is using tip or or ring.
I'd consider putting the TRRS socket in the end of a piece of tubing to use as a mic boom. something just big enough to accommodate the socket.
Tony.
The mic uses the second ring (furthest from tip) and sleeve connections. I purchased a four pole TRRS socket and just ran a shielded mic cable from the second R and sleeve connection to an RCA that I use with my dedicated mic pre. I'm not sure whether a 3.5mm mic input is using tip or or ring.
I'd consider putting the TRRS socket in the end of a piece of tubing to use as a mic boom. something just big enough to accommodate the socket.
Tony.
Anyone know of any real time analysis software like that's with the OmniMic that could be used with this little mic. Something that will plot a line and then you can make a change in your crossover to compare?
REW or ARTA would be the two main pieces of software that you could do an RTA type measurement with (using pink noise), and see changes in real time.
You can also do frequency sweeps with both to produce an spl graph.
Holm impulse is another option for doing frequency sweeps.
Holmimpulse and REW are both free. ARTA is shareware, but can be used in demo mode.
Out of the three holmimpulse is probably the easiest to get started with (but may require some work to get going on windows 10). REW works on Macs as well as PC and linux.
Tony.
You can also do frequency sweeps with both to produce an spl graph.
Holm impulse is another option for doing frequency sweeps.
Holmimpulse and REW are both free. ARTA is shareware, but can be used in demo mode.
Out of the three holmimpulse is probably the easiest to get started with (but may require some work to get going on windows 10). REW works on Macs as well as PC and linux.
Tony.
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Would love to be able to do this like the Dayton V2, if its an option on the cheaper mics though I may just go for one of those and save myself money.
Dayton Omnimic Real-time Measurement Demo - YouTube
Dayton Omnimic Real-time Measurement Demo - YouTube
Hmm it's been a couple of years since I looked at it. Maybe there has been a change. I can see conceptually if you can set two different inputs for the incoming signal you could do it, ie independent sound sources for input, channel one the usb mic, and channel 2 line in. Without that capability it won't work. I didn't think that the accoustic reference is applicable to these types of measurements, but re-reading that desciption, maybe it can.
Tony.
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The feature was introduced in 2016 to provide a timing reference mechanism for USB microphones using only the measurement input. There is a fixed timing relationship between the timing signal sent to the reference speaker and the measurement signal sent to the speaker or driver being measured. As long as the timing reference speaker and microphone are not moved relative timing is preserved between measurements.
Tony, I am interested in your comments and recommendation of the IM66.
Can you expand on your testing methodology using this mic and/or link to the associated hardware/software you use..? 🙂
best,
Bob
Hi Bob, I will have to answer later. I just spent about 20 minutes writing a reply and got a timeout message and lost it (and lunch is pretty much over). arrghh.
Tony.
Tony.
That is so annoying. Long text may be better in Word or a simular editor first then copy and paste. We would have all liked to have seen your thoughts on it.
OK second attempt 🙂 this time drafted in wordpad. I rarely have a problem where I lose a post but it was probably for the better as I think this one is an improvement 😉.
Firstly I have been using a diy mic for years, it is a panasonic WM60AY capsule on the end of a 1M long piece of copper tube that is the same diameter as the capsule. The reason I bought the dayton was that although the WM60AY is reportedly extremely flat I was never 100% sure I could trust the measurements I did with it, and the dayton comes with its own individual cal file. Hard to beat at about $30AU.
The other main components in my test setup are:
* A small LM3886 amp (though I have found that it is not so great at low impedances and something better able to handle low impedance speakers may be better).
* an Eric Walin Mic preamp
* a gen 1 focusrite 2i2 USB sound interface
* an Eric Walin Jig II testing jig http://espacenomeutente.altervista.org/wp-content/uploads/2019/09/jigII.pdf Note that you can do a much simpler setup with Claudio's cable jigs Cables
Note that I am currently working on a circuit for using electret mics directly from the phantom power of the focusrites mic preamp. it is also possible if you have a sound interface with mic pre's to use a battery box to power the electret. If you have a mic preamp built into the sound interface it makes sense to use it 🙂
I've made up various cables. I use a 1/4" TS jack to rca for the output on the focusrite, and I use an rca to TRS 1/4" plug (with rca hot to T and rca ground connected to R not sleeve) for the input (as my Walin preamp has rca out).
Software wise, I used to use holmimpulse almost exclusively, but have started now to use REW. Note my comments earlier about USB mics and REW were not correct, and you can get timing info using the acoustic timing signal, I have not actually tried this myself, as I can do dual channel measuements.
Now so far I have only done comparison measurements with the Dayton IMM6 and used it to create a cal file for my trusty old WM60AY mic. Part of the reason was that was easier than making up a new wand to use it on 😉 But My idea for it was that a tube with a TRRS jack in the end of it that the dayton could plug into would be the best way to use it. On budget I think it is extremely hard to beat, and it has the advantage that you can plug it into your smart phone (if you have one with a headphone/mic jack). If you are willing to pay around three times the price, there are a number of other calibrated mics, both phantom powered and USB on the market.
I made up a TRRS to RCA cable to use the dayton with my Walin pre. You can work out which pins on the TRRS socket to use by plugging in the mic and using a multimeter set to ohms. The mic has an impedance around 2K.
As far as doing measurements I'm still learning. It is amazing how many little things make a difference. Trying to get as clear an area as possible with nothing that can interfere with the sound wave propagation is essential, if you can measure outside away from any boundaries all the better, if you can't a big room with the speaker in the centre and mic oriented oblique to any walls helps, mic and speaker roughly half way between floor and ceiling if possible.
Attached is a picture of an outside measurement day, with my rather dodgy setup. I really should make an extendable pole with a spike on the end that I can just push into the lawn for the mic wand to attach to. I'm pretty sure I get reflections off the step ladder.
Also attached is a pic of a couple of the cables I made up.
Tony.
Firstly I have been using a diy mic for years, it is a panasonic WM60AY capsule on the end of a 1M long piece of copper tube that is the same diameter as the capsule. The reason I bought the dayton was that although the WM60AY is reportedly extremely flat I was never 100% sure I could trust the measurements I did with it, and the dayton comes with its own individual cal file. Hard to beat at about $30AU.
The other main components in my test setup are:
* A small LM3886 amp (though I have found that it is not so great at low impedances and something better able to handle low impedance speakers may be better).
* an Eric Walin Mic preamp
* a gen 1 focusrite 2i2 USB sound interface
* an Eric Walin Jig II testing jig http://espacenomeutente.altervista.org/wp-content/uploads/2019/09/jigII.pdf Note that you can do a much simpler setup with Claudio's cable jigs Cables
Note that I am currently working on a circuit for using electret mics directly from the phantom power of the focusrites mic preamp. it is also possible if you have a sound interface with mic pre's to use a battery box to power the electret. If you have a mic preamp built into the sound interface it makes sense to use it 🙂
I've made up various cables. I use a 1/4" TS jack to rca for the output on the focusrite, and I use an rca to TRS 1/4" plug (with rca hot to T and rca ground connected to R not sleeve) for the input (as my Walin preamp has rca out).
Software wise, I used to use holmimpulse almost exclusively, but have started now to use REW. Note my comments earlier about USB mics and REW were not correct, and you can get timing info using the acoustic timing signal, I have not actually tried this myself, as I can do dual channel measuements.
Now so far I have only done comparison measurements with the Dayton IMM6 and used it to create a cal file for my trusty old WM60AY mic. Part of the reason was that was easier than making up a new wand to use it on 😉 But My idea for it was that a tube with a TRRS jack in the end of it that the dayton could plug into would be the best way to use it. On budget I think it is extremely hard to beat, and it has the advantage that you can plug it into your smart phone (if you have one with a headphone/mic jack). If you are willing to pay around three times the price, there are a number of other calibrated mics, both phantom powered and USB on the market.
I made up a TRRS to RCA cable to use the dayton with my Walin pre. You can work out which pins on the TRRS socket to use by plugging in the mic and using a multimeter set to ohms. The mic has an impedance around 2K.
As far as doing measurements I'm still learning. It is amazing how many little things make a difference. Trying to get as clear an area as possible with nothing that can interfere with the sound wave propagation is essential, if you can measure outside away from any boundaries all the better, if you can't a big room with the speaker in the centre and mic oriented oblique to any walls helps, mic and speaker roughly half way between floor and ceiling if possible.
Attached is a picture of an outside measurement day, with my rather dodgy setup. I really should make an extendable pole with a spike on the end that I can just push into the lawn for the mic wand to attach to. I'm pretty sure I get reflections off the step ladder.
Also attached is a pic of a couple of the cables I made up.
Tony.
Attachments
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Very good Tony. A lot of that went over my head as I'm a little confused with all this measurement business but I get the gist of it and I'm sure others will benefit to what you've written more. I may actually look at what you have done again as my learning curve improves.
That little mic does look like a very attractive option I have to say. However once you factor in a interface such as the 2i2 (looking at around 100-150 in the uk) you are not far from a USB all in one. Unless there are other cheap interfaces which will just work with the mic out there. As I understand it its a TRS plug. And some of these are even not the same as some manufactures change the have different configurations of its set up. Samsung, different to iphone or some laptops perhaps if those even have one. I cant say for sure its only what I've come across in the past. If I knew it would be an easy plug and play I think I would go for the cheap option as the mic seems to get great reviews.
That little mic does look like a very attractive option I have to say. However once you factor in a interface such as the 2i2 (looking at around 100-150 in the uk) you are not far from a USB all in one. Unless there are other cheap interfaces which will just work with the mic out there. As I understand it its a TRS plug. And some of these are even not the same as some manufactures change the have different configurations of its set up. Samsung, different to iphone or some laptops perhaps if those even have one. I cant say for sure its only what I've come across in the past. If I knew it would be an easy plug and play I think I would go for the cheap option as the mic seems to get great reviews.
Actually it is a TRRS plug (four contacts rather than the more usual three) I think that is so you can have stereo + mic on a headset. I think it should be standardized but there is always the chance that someone makes a proprietry version so you have to use their headsets / accessories with their phone. It works fine on my ancient samsung galaxy S5.
I originally bought the focusrite because I also wanted to use it for measuring amps etc which you need stereo, and very low distortion and noise floor for (not important for doing speaker measurements, where the noise floor is much higher as is distortion). I'm pretty sure others here have posted about cheaper bheringer sound interfaces that they use for speaker measurements.
Tony.
I originally bought the focusrite because I also wanted to use it for measuring amps etc which you need stereo, and very low distortion and noise floor for (not important for doing speaker measurements, where the noise floor is much higher as is distortion). I'm pretty sure others here have posted about cheaper bheringer sound interfaces that they use for speaker measurements.
Tony.
In the line of Tony's recommendations, in case your PC or PC soundcard has separated mic input and line outputs, you could simply download ARTA for free and get yourself a cheap (a Pound or so) electret condensor mic capsule. All you need to do is to solder connecting cable and some sort of pipe to mount the -very tiny: 6mm dia or so- mic capsule. The original Panasonic WM 61has disappeared it seems, but various remade clones such as Monacor MC 4001 are readily available and and dirt cheap.
The mic input of a PC or soundcard saves you a separate mic preamp.
All you need to do is set the PC input and output right, connect an amp between line out and speaker, and start experimenting.
For starting experiments this will work fine. Sets you back a few Pounds only, an will help you to get your feet wet slowly. Once you feel safe, then it is time for Focusrite & friends and aim for accuracy.
The mic input of a PC or soundcard saves you a separate mic preamp.
All you need to do is set the PC input and output right, connect an amp between line out and speaker, and start experimenting.
For starting experiments this will work fine. Sets you back a few Pounds only, an will help you to get your feet wet slowly. Once you feel safe, then it is time for Focusrite & friends and aim for accuracy.