You are correct. I did that one too fast, your chart only goesto 200 Hz, i scaled 20 Hz to the lower limit. I have corrected the horizontal scale to properly match and replaced the erroneous graph.
dave
Nobody knows for sure how the MA data was 'created'. People asked Mark Fenlon specifically for details but he just gave evasive answers.
The graphs are scaled to look good on paper.
Drivers should be measured in an infinite baffle at different angles and levels under anechoic conditions. This would create useful data.
Spreading misinformation again, eh?
Mark has given that information often. On an IEC baffle in an anechoic chamber with an Earthworks M30 using LMS. Industry standard stuff. He adds no smoothing unlike most others.
dave
Once properly rescaled it shows broadly similar dips and then some. IIRC Ryan said your measures are only good to 600 Hz, Mark shows that dip a little lower.
dave
Perhaps you missed my comment Dave, but the Vifa comparison was also scewed unfortunately: http://www.diyaudio.com/forums/full...-class-full-range-drivers-47.html#post4240221
I think that one would line up a bit better. Still some small discrepency.
I think that one would line up a bit better. Still some small discrepency.
LMS isn't available since 2010?
LMS - Loudspeaker Measurement System
Which IEC baffle?
What size is the anechoic chamber? What is its lower cutoff? Has anybody ever seen that anechoic facility?
What excitation signal was used?
Please answer before accusing me of spreading misinformation.
Here's an essentially-anechoic measurement versus a 12ms gate time:
Here's the same measurement with 10, 5, and 2.5ms gate times.
That's no smoothing on any of them. You can see what happen as you "erase" data from the impulse response. It's important to recognize that Mark's data would be comparible to the first curve. XRK's would be somewhere between the 2.5 and 5ms curves.
Just FYI.
Here's the same measurement with 10, 5, and 2.5ms gate times.
That's no smoothing on any of them. You can see what happen as you "erase" data from the impulse response. It's important to recognize that Mark's data would be comparible to the first curve. XRK's would be somewhere between the 2.5 and 5ms curves.
Just FYI.
I am appalled at the continuing attack on Mark. I know him personally and he is far from a snake oil salesman or evasive con man. He develops his drivers using solid engineering, detailed high tech instrumentation, and very high quality materials and processes.
He cares about music and he cares about his customers. He was here in diy to get closer to his customers.
Some of you should be ashamed of yourselves.
Note that there appears to be a dip at 350hz in the green colored 5ms curve? That dip isn't real, despite being almost a full octave above the gate of 200hz. This is why I say these windowed measurements aren't very useful <2.5/Tgate. Maybe even 3/Tgate if you want to play safe.
I offer no opinion on any manufacturer data here, other than to point out that if 'nobody knows' how the data from one manufacturer was generated, then the same whinge must be equally applied to the majority of others.
However: since Pnix is deliberately singling out Mark Audio, claiming they provide inadequate information and fail to use reasonable equipment, he must now present his detailed information about the equipment Vifa, Tang Band, Fostex, Scan Speak, SB Acoustics, HiVi, Dayton, PARC audio, Jordan, EAD, Supravox, PHY, AER, Lowther, Voxativ, Aurasound, Peerless, Fountek etc. all use, together with a detailed statement as to how this equipment was used in obtaining their published measurements. Failure to do so will be an admission that he does not in fact possess sufficient knowledge to comment on this matter.
However: since Pnix is deliberately singling out Mark Audio, claiming they provide inadequate information and fail to use reasonable equipment, he must now present his detailed information about the equipment Vifa, Tang Band, Fostex, Scan Speak, SB Acoustics, HiVi, Dayton, PARC audio, Jordan, EAD, Supravox, PHY, AER, Lowther, Voxativ, Aurasound, Peerless, Fountek etc. all use, together with a detailed statement as to how this equipment was used in obtaining their published measurements. Failure to do so will be an admission that he does not in fact possess sufficient knowledge to comment on this matter.
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I'm presenting and asking for information on technical issues. How can this be considered as a personal attack on Mark Fenlon?
Here's an essentially-anechoic measurement versus a 12ms gate time:
Here's the same measurement with 10, 5, and 2.5ms gate times.
That's no smoothing on any of them. You can see what happen as you "erase" data from the impulse response. It's important to recognize that Mark's data would be comparible to the first curve. XRK's would be somewhere between the 2.5 and 5ms curves.
Just FYI.
What driver is this?
To be fair, as an ex-Mark-Audio-fan-boy, I've been met with rudeness and deleted posts when asking questions or comparing data. Mark does not like DIY'ers measuring his drivers. It's just a reality. It bugs him. I could go on, but it's just salt in an open wound that I'm not interested in rubbing.
Been so long I can't remember. Looks like a woofer. I think it was from a Silver Flute 8". I've shown these graphs before. I could make similar ones with more recent woofers I've measured if you prefer. I have better technique and gear now.
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Exactly, they all don't tell their customers much about the performance of their products. Just because everybody does it doesn't make it right.
Good comparison but it still doesn't explain why there are such huge discrepancies at higher frequencies. Anechoic data and gated data should track quite good. See the TC9 data I've posted. The MA data doesn't show much resemblance.
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Which raises the rather significant question of why you only appear to whine about anything and everything from a single manufacturer.
You cannot provide that information for the large number of other companies I listed, so by definition, you are not in a position to continuously misrepresent one as being worse in this respect than others.
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