Hey all,
I think I am done building stuff with traced files and want to start using a mic to get FRD files. Does anyone have a recommendation? Budget is around $150. I cannot justify over that for the amount I will use it. I do know they are only good for 5 years or so. There are a bunch of them on Parts Express and honestly I do not know the difference. It would be nice If I could use them to make FRD files of ported units.
I saw there is a way to create such a file but you need to have the time alignment correct and that this requires a secondary part. I think this is best. If I am going through all the trouble then I would like to be able to create FRD files for ported subs.
Secondly, it is worth buying a DATS system? Are DATS zma files more accurate than what is posted by the makers online? I do understand manufacturing variables but are they far enough off to make a serious difference in the sound?
I get how a company would fudge their FRD graph to get some more sales. I have seen quite a few drivers come no where near what the manufacturer graph claims. This is why I am doing this. Sick of building a whole unit and not getting what I expected.
Well let me know what you recommend or what you use that has been working out well for you. Thanks everyone.
I think I am done building stuff with traced files and want to start using a mic to get FRD files. Does anyone have a recommendation? Budget is around $150. I cannot justify over that for the amount I will use it. I do know they are only good for 5 years or so. There are a bunch of them on Parts Express and honestly I do not know the difference. It would be nice If I could use them to make FRD files of ported units.
I saw there is a way to create such a file but you need to have the time alignment correct and that this requires a secondary part. I think this is best. If I am going through all the trouble then I would like to be able to create FRD files for ported subs.
Secondly, it is worth buying a DATS system? Are DATS zma files more accurate than what is posted by the makers online? I do understand manufacturing variables but are they far enough off to make a serious difference in the sound?
I get how a company would fudge their FRD graph to get some more sales. I have seen quite a few drivers come no where near what the manufacturer graph claims. This is why I am doing this. Sick of building a whole unit and not getting what I expected.
Well let me know what you recommend or what you use that has been working out well for you. Thanks everyone.
Cross Spectrum still are in business, aren’t they? The EMM-6 is just right to start with. You need an audio interface too, with microphone input and +48V phantom power. Look for the Behringer UMC202HD. The ARTA user manual tells you how to build an impedance bridge from practically scrap.
There are many ways to measure impedance, each using different equipment or software, and all of similar usable accuracy and using similar methods.
As for whether measured is better than traced, you might get away with traced especially if you check your responses after crossing, by measuring them. I would be more comfortable measuring impedance but there are many more questionable shortcuts you could take
I need an external sound card for that jig right?
Do you have a recommendation for that unit? I see there are hundreds available and have no idea what is good or not
I see that UMC202HD is about $100. That and the mic is within budget. I'll need two XLR jacks rights? One to link the mic and one to link the preamp to itself.
One last question: When taking frequency sweeps of a ported subwoofer, why don't people just take a far field measurement? Wouldn't that include both the driver and the port itself output at the listening position? Why take two nearfield measurements and then combine them?
Yes, you need the external sound card for the impedance jig, but you need it ANYWAY for the microphone. Amazon has an "open box" Behringer UMC202HD for $88. (It is listed under "used" but is sold by Amazon Warehouse. They usually indicate the condition. The one lists is "Like New" but if it was cheaper and had a scratch on it, would it matter?)
Parts Express always has 10-12% off on major holidays, so wait until this weekend or the next holiday for the EMM-6.
I haven't bought these cables at Parts Express, I'm sure they have them but don't know if they are cheaper than Amazon:
Parts Express always has 10-12% off on major holidays, so wait until this weekend or the next holiday for the EMM-6.
I haven't bought these cables at Parts Express, I'm sure they have them but don't know if they are cheaper than Amazon:
- For that impedance jig you will need Three TRS to RCA cables. For this, get one TRS to RCA cable, and get two TRS-to-TRS male cables and two TRS-to-RCA adapters. Then you will have the TRS-to-TRS cables that you need below.
- Some alligator clips
- For measurements you will need:
- a 20-25 ft XLR microphone cable
- A TRS to RCA cable (probably short) from the output of the Behringer interface to an amplifier (but you can use one of the ones from the impedance jig)(already listed above for the impedance jig)
- A TRS-to-TRS cable (probably short) to run from the output of the Behringer interface to the input of the Behringer interface for Loopback (already listed above for the impedance jig)
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Because you cannot measure subwoofers accurately at low frequencies in rooms. If you place your mic 3-4m away it will measure the +/- 20 dB dips and peaks caused by the room resonances and not the smooth output of the subwoofer.
Quite frankly there is little practical need to measure subwoofers because their output is the same in all directions and pretty accurately given by a simple lumped model using the driver, port and box parameters (which need to be known). Likely as accurate as messing about with near field measurements. Measurements can help with distortion levels though and measuring the room response is pretty much essential for sorting out a high quality low frequency response. Measurements are also pretty useful at higher frequencies for resonances, radiation patterns, etc... so a mic is effectively required to design a speaker just not so much for output at subwoofer frequencies.
Cross Spectrum Labs seems to be on hiatus at the moment-
Shipping update (Apr 22, 2022):
EMM-6 microphones will be available in the coming weeks.
We will not be able to respond to inquiries about availability. The most up-to-date information will be published here.
Reference:
https://www.cross-spectrum.com/measurement/calibrated_dayton.html
"Shipping update (Apr 26, 2024): We apologize for the lack of updates. UMIK-1 mics are currently unavailable. A combination of health issues, equipment issues and project schedules have consumed the bulk of our energy as of late and we haven't had time to focus on microphones. We will continue to sell calibrated microphones and meters - we do have some units in stock that we haven't been able to process and offer for sale yet. We just need a little patience from everyone. Thanks for your understanding, and we'll provide further updates as we have them."
Reference:
https://cross-spectrum.com/measurement/calibrated_umik.html
@A4eaudio
How important is it to have an electronic compensation file for one's mic? Can he just one and use as-is?
Shipping update (Apr 22, 2022):
EMM-6 microphones will be available in the coming weeks.
We will not be able to respond to inquiries about availability. The most up-to-date information will be published here.
Reference:
https://www.cross-spectrum.com/measurement/calibrated_dayton.html
"Shipping update (Apr 26, 2024): We apologize for the lack of updates. UMIK-1 mics are currently unavailable. A combination of health issues, equipment issues and project schedules have consumed the bulk of our energy as of late and we haven't had time to focus on microphones. We will continue to sell calibrated microphones and meters - we do have some units in stock that we haven't been able to process and offer for sale yet. We just need a little patience from everyone. Thanks for your understanding, and we'll provide further updates as we have them."
Reference:
https://cross-spectrum.com/measurement/calibrated_umik.html
@A4eaudio
How important is it to have an electronic compensation file for one's mic? Can he just one and use as-is?
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It is effectively essential if you have even a passing interest in accuracy. Here is the response of a bunch uncalibrated microphones of the same model.
ctrlx already pointed out that you can correct every budget microphone using a tweeter with known response. Way back I did so, and later discovered I was only 1dB off at high frequencies. But still I’d get a corrected mike (not that hard over here). Properly used and stored, they actually don’t drift.
For low frequencies measuring level accurately is less important due to room modes and boundary reinforcement (or not). In other words, LF playback is always compromised by the room.
Btw not only the EMM-6 but also the Sonarworks SoundID mike comes with individual correction files. The Sonarworks even with a bonus ‘diffuse field’ file. I see that B&H has it for $89 ex tax.
For low frequencies measuring level accurately is less important due to room modes and boundary reinforcement (or not). In other words, LF playback is always compromised by the room.
Btw not only the EMM-6 but also the Sonarworks SoundID mike comes with individual correction files. The Sonarworks even with a bonus ‘diffuse field’ file. I see that B&H has it for $89 ex tax.
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The calibration file that came with my EMM-6 was obvious nonsense having been taken in the presence of strong reflections. To be fair to Dayton they acknowledged the problem and were willing to pay to have it calibrated by Cross Spectrum labs in the US but being based in Europe it didn't seem worth the time, effort and possible cost dealing with customs and the like. I used an average of the tweeters I had to hand and didn't bother with the low frequency end. The calibration files that come with cheap mics probably need viewing with a degree of caution and are best checked.
Microphone calibrations do change with time (and pressure, temperature, etc...) and at work they would normally use a mic with a calibration that was less than a year old when performing measurements for clients. This is pretty typical and for measurements with legal standing likely to be a requirement as is using a certified calibration service and not what comes with a microphone. A pistonphone would typically be used before and after a set of measurements along with measuring the atmospheric conditions. For DIY at home one wouldn't normally bother but knowing what is involved in taking accurate measurements may help with getting a feel for the likely accuracy of home measurements.
Microphone calibrations do change with time (and pressure, temperature, etc...) and at work they would normally use a mic with a calibration that was less than a year old when performing measurements for clients. This is pretty typical and for measurements with legal standing likely to be a requirement as is using a certified calibration service and not what comes with a microphone. A pistonphone would typically be used before and after a set of measurements along with measuring the atmospheric conditions. For DIY at home one wouldn't normally bother but knowing what is involved in taking accurate measurements may help with getting a feel for the likely accuracy of home measurements.
The EMM-6 price has come down over the last few months to $55. There have been concerns about the accuracy of the calibration file in the past. Given the OP's budget, I'd say it's his only choice. He can send it to Cross Spectrum or have a DIYer create a better calibration file in the future.
@Bmsluite - I'm interested in the accuracy of a new 2024 EMM-6 (I have data for the calibration file for one from many years ago which wasn't very accurate). If you will pay for shipping I'd purchase one this weekend, have it shipped to me to test, make a more accurate calibration file based on an Earthworks M23R mic, and send it on to you at cost + actual shipping. PM me if interested.
@Bmsluite - I'm interested in the accuracy of a new 2024 EMM-6 (I have data for the calibration file for one from many years ago which wasn't very accurate). If you will pay for shipping I'd purchase one this weekend, have it shipped to me to test, make a more accurate calibration file based on an Earthworks M23R mic, and send it on to you at cost + actual shipping. PM me if interested.
After a bit more research and seeing how everyone ends up with about 6 mics........ I decided to go with my "buy once, cry once" philosophy. I will be buying that Behringer preamp ( i found and open box one for $78) and a Nady CM-100 mic ($90). I found through some digging that for the price the Nady seems to be the best. It also has a lot less floor noise than the Dayton units.
Question about loop back cables. I might sound stupid here but I would rather ask and sound stupid rather than do and actually BE stupid.:
Exactly what type of cable is this loopback cable? Is it a stereo 6.35 male jack to two mono RCA jacks? I couldn't quite narrow down exactly which cable is needed for loopback. If you could explain this to me or show me an example it would be greatly appreciated.
I did see similar reports in my research. I decided upon the Nady CM-100 and the behringer preamp. $30 more than I wanted to spend but I am sure it will be money well spent.
I responded to your PM. I am very interested to see your DATS jig research project
That Nady seems another ECM8000… it’s ok. For anything above 5kHz, get an unique correction file.
The loopback is the cable that connects left line output to left line input. You need ‘stereo’ 6,3mm jack to ‘stereo’ jack (actually balanced in-and outputs).
For the impedance measurement, get mono jack cables for the inputs and an amp with black=ground (no bridged amps). And build the resistor rig from the ARTA manual.
The loopback is the cable that connects left line output to left line input. You need ‘stereo’ 6,3mm jack to ‘stereo’ jack (actually balanced in-and outputs).
For the impedance measurement, get mono jack cables for the inputs and an amp with black=ground (no bridged amps). And build the resistor rig from the ARTA manual.
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