Both of my drivers measure better than factory curves.
Here's the factory chart:
Here's what I measured with REW nearfield, driver in 60 liter box with 44Hz tuned port. Sorry no off axis on this. Port output not included.
I would not use this driver higher than 1500Hz tops. With LR4 at 800 or 1000 Hz, there's no need to notch filter the breakup as it's far enough down to have no audible effect.
Don't know actual SPL level; probably close to 80~85 dB/1m.
Mike,
Thank for the measurement
Please be aware that REW has a built in smoothing function of 1/24th octave.
“The fundamental and harmonic plots derived from sweep measurements are smoothed to 1/24 octave. This cannot be adjusted”
SB do not use smoothing and include all effects of room/floor bounce.
If you would line to make accurate SPL readings, please consider getting an SPL calibrator. In modern era about $199 or less and will enable accurate SPL reports to about +/- 0.4dB.
Alternatively if you have iPhone you can have a guesstimate that is within about +/- 2dB.
Thank for the measurement
Please be aware that REW has a built in smoothing function of 1/24th octave.
“The fundamental and harmonic plots derived from sweep measurements are smoothed to 1/24 octave. This cannot be adjusted”
SB do not use smoothing and include all effects of room/floor bounce.
If you would line to make accurate SPL readings, please consider getting an SPL calibrator. In modern era about $199 or less and will enable accurate SPL reports to about +/- 0.4dB.
Alternatively if you have iPhone you can have a guesstimate that is within about +/- 2dB.
Reference:
https://www.cdc.gov/niosh/noise/about/app.html
https://www.cdc.gov/niosh/noise/about/app.html
@tktran303
That was measured with UMIK1 + calibration file, which is supposed to take care of SPL as well as FR, afaik.
I have Audio Tool on my phone, which in combination with Dayton Audio iMM-6, is decent.
I also use a mic SPL calibrator (94 or 114 dB reference 1kHz tone) with better than 0.5 dB accuracy. I've used 2 for 20+ years.
These all are made to jibe with one another.
So I'm reasonably confident that the measured data is fairly accurate. No additional smoothing was used, iirc. 1/24 oct smoothing is pretty minimal, too, btw -- unsmoothed isn't always that useful esp when measuring in a smallish room. (22x20x9')
I said I didn't know the SPL level because standard SPL is usually taken at 1m distance, and for that measurement, the mic was about a centimeter of the center of the cone. So naturally the SPL registered by REW here is way higher than it would be at 1m.
The other thing is, to address @ErnieM re the cone breakup, I don't hear it in any glaring way when I play anything through it while holding the driver in my hand. Which kinda confirms my measurement: The breakup is not that bad.
An Aside: This listening to both music and tones via speaker held in hand (or hanging very close, not mounted on any baffle) is something I do mostly with cone drivers & sometimes tweeters; it give me some correlation between what I measure & what I hear -- w/o which I'd only be designing by measurements or principles. I can't see that being effective without ramping up my measurement systems 10X. OTOH, my ability to listen & analyze what I hear is pretty good, and absolutely key to my speaker design & building. It isn't as thoroughly science/measurement based as some of the supastars at DIYaudio, but I have built lots of speakers that most musicians & music lovers & audiophiles -- and my wife! -- really like.
That was measured with UMIK1 + calibration file, which is supposed to take care of SPL as well as FR, afaik.
I have Audio Tool on my phone, which in combination with Dayton Audio iMM-6, is decent.
I also use a mic SPL calibrator (94 or 114 dB reference 1kHz tone) with better than 0.5 dB accuracy. I've used 2 for 20+ years.
These all are made to jibe with one another.
So I'm reasonably confident that the measured data is fairly accurate. No additional smoothing was used, iirc. 1/24 oct smoothing is pretty minimal, too, btw -- unsmoothed isn't always that useful esp when measuring in a smallish room. (22x20x9')
I said I didn't know the SPL level because standard SPL is usually taken at 1m distance, and for that measurement, the mic was about a centimeter of the center of the cone. So naturally the SPL registered by REW here is way higher than it would be at 1m.
The other thing is, to address @ErnieM re the cone breakup, I don't hear it in any glaring way when I play anything through it while holding the driver in my hand. Which kinda confirms my measurement: The breakup is not that bad.
An Aside: This listening to both music and tones via speaker held in hand (or hanging very close, not mounted on any baffle) is something I do mostly with cone drivers & sometimes tweeters; it give me some correlation between what I measure & what I hear -- w/o which I'd only be designing by measurements or principles. I can't see that being effective without ramping up my measurement systems 10X. OTOH, my ability to listen & analyze what I hear is pretty good, and absolutely key to my speaker design & building. It isn't as thoroughly science/measurement based as some of the supastars at DIYaudio, but I have built lots of speakers that most musicians & music lovers & audiophiles -- and my wife! -- really like.
My apologies- SPL reading from USB connected mic is accurate enough.
I was commenting that the measurement “measure better than factory specs” is because of the measurement (near field- which looses precision as frequencies get higher) and the display method (smoothed)
Both combine to make it appear better than the datasheet. My apologies I was not aware it a nearfield measurement.
For other readers, may I add that a near field measurement looses precision as the frequency get higher. The SPL view with a 1000ms will show this.
eg.
VIEW 1: REW SPL + phase view
VIEW 2: Distortion chart (always includes 1/24th octave smoothing)
VIEW 2b)
VIEW 2o)
The SPL view in the Distortion view is always 1/24th smoothed.
When you can see the harmonics, as in View 2a), this can assist with selecting an appropriate high pass point
View 2o) is complete OPTIONAL, ie. a low noise microphone able to peer down to 10dB or lower, is NOT needed for crossover design work.
VIEW 3:
The 1m view has the advantage of being able to show the effect of the narrow baffle. Unfortunately, due the method of the exponential sine sweep measurement process, there is some smoothing due to the 5m gate, and a complete loss of accuracy below 200Hz (1/5ms)
VIEW 4:
A full polar view might further assist with understanding the directivity of the transducer, in box. This may help with choosing the appropriate low pass point.
One line conclusion:
Appearance of high frequency breakups will vary based on view.
I was commenting that the measurement “measure better than factory specs” is because of the measurement (near field- which looses precision as frequencies get higher) and the display method (smoothed)
Both combine to make it appear better than the datasheet. My apologies I was not aware it a nearfield measurement.
For other readers, may I add that a near field measurement looses precision as the frequency get higher. The SPL view with a 1000ms will show this.
eg.
VIEW 1: REW SPL + phase view
VIEW 2: Distortion chart (always includes 1/24th octave smoothing)
VIEW 2b)
VIEW 2o)
The SPL view in the Distortion view is always 1/24th smoothed.
When you can see the harmonics, as in View 2a), this can assist with selecting an appropriate high pass point
View 2o) is complete OPTIONAL, ie. a low noise microphone able to peer down to 10dB or lower, is NOT needed for crossover design work.
VIEW 3:
The 1m view has the advantage of being able to show the effect of the narrow baffle. Unfortunately, due the method of the exponential sine sweep measurement process, there is some smoothing due to the 5m gate, and a complete loss of accuracy below 200Hz (1/5ms)
VIEW 4:
A full polar view might further assist with understanding the directivity of the transducer, in box. This may help with choosing the appropriate low pass point.
One line conclusion:
Appearance of high frequency breakups will vary based on view.
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Very thorough, @tktran303 Thank you for the details.
I still don't hear the breakup as a serious issue if you low pass where you should with any 12": Ideally, at or below 1khz where both FR and directivity start going south.
I still don't hear the breakup as a serious issue if you low pass where you should with any 12": Ideally, at or below 1khz where both FR and directivity start going south.
Totally with you. I had my eye on that driver, and was going to crossover somewhere between 700Hz and 1KHz, because as you say it starts to get directive.
And yes, agreed that measuring or listening in the nearfield is a good strategy, to mitigate the influence of the baffle/environment/room.
I forgot to ask before- any reason you chose this over the nero-15mwn700d?
And yes, agreed that measuring or listening in the nearfield is a good strategy, to mitigate the influence of the baffle/environment/room.
I forgot to ask before- any reason you chose this over the nero-15mwn700d?
It was a size thing -- had to be 2cf max, and I thought it too small for 15"s. Didn't even think about the 15; probably should have checked. Has anyone modeled the 15mwn700 in enclosures?
Also I doubted the 14x10 horn + ROSSO-44CDN-PK combo could be crossed low enough in a 15" 2-way. I'm pushing it at 800 & 1000Hz, and getting away with it because the speakers won't be played loudly enough to raise distortion much. It's 110 dB sensitivity. But with a 15", I'd want to cross maybe 600 or lower and that's definitely too low for this horn & CD even at home SPL levels. And there was no budget or time to design/build an active 3-way.
The 12mwd700 is a good driver. I will try it for 120~700 Hz duty in a 4-way OB. I am hoping it will further improve the high bass / low mid area over 8" drivers I've used for this role with previous OB versions.
Also I doubted the 14x10 horn + ROSSO-44CDN-PK combo could be crossed low enough in a 15" 2-way. I'm pushing it at 800 & 1000Hz, and getting away with it because the speakers won't be played loudly enough to raise distortion much. It's 110 dB sensitivity. But with a 15", I'd want to cross maybe 600 or lower and that's definitely too low for this horn & CD even at home SPL levels. And there was no budget or time to design/build an active 3-way.
The 12mwd700 is a good driver. I will try it for 120~700 Hz duty in a 4-way OB. I am hoping it will further improve the high bass / low mid area over 8" drivers I've used for this role with previous OB versions.
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