Yes. They answer that way because it's inherently true. A proper measurement environment and equipment is / are superior to anything most of us have access to. Alas. There's a reason they exist.
Sure but that doesn't invalidate gated measurements. There's an accuracy level that is good enough. Gated measurements are good enough if one understands the limitations and uses them correctly. Which I think is what I did with my Alpair measurements.
Indeed. They would make a very good low cost 2-way (FASTish) crossed conservatively at around 300Hz. Even the venerable (and otherwise horrible above 300) Dayton DC160 Zaph|Audio would serve well for such a "budget" low end, since the TC9 not only reaches three octaves lower than the dome in the cone-and-dome kit PE used to sell, but it performs better on the high end as well.
I seem to remember seeing something akin, if not almost exactly that last year on one of the forums. Not sure which; I'll see if I can find it somewhere.
The files are huge and beyond size limit for uploads. Unless there is a way to save it compactly? I suspect the .wav audio file is embedded in the .mdat file. PM me and I can email it to you if still interested.
Why not upload the file to Dropbox or a similar site?
The pronounced null and peaks that show in the manufacturer and vendor data sheets are still missing, even with the "expanded" scale. It will be interesting to determine why . . .Now with warts exposed, you can see that the 60 deg data is about the same in both measurements.
Sure but that doesn't invalidate gated measurements. There's an accuracy level that is good enough. Gated measurements are good enough if one understands the limitations and uses them correctly. Which I think is what I did with my Alpair measurements.
As I've said several times, I'd concur. Nothing wrong with your measures with two caveats -the frankly excessive expectations of off-axis performance (it's not going to happen with a 4in out past 30 degrees. Would that it did) & that I'd be wary of assuming how accurate those are out past 30 with the gear. I said the same to X above, as you probably noticed. I've said the same elsewhere. The results in both / all cases might be better than indicated (not impossible) -they might also be worse (likewise). For the sake of interest, I asked a bod I know over at the University of Salford who does a lot of work in their anechoic chamber for his views. Same reaction. This is not a personal remark, or denigrating anything or anybody -it's just what it is.
Of course they make money. Not a crime, last I checked.
I.....
I regretfully gave up on that happy illusion some time ago, much as I wish it were true.
Nobody denies much of the gear available to us is very capable, but it's not up to those levels and you're kidding yourself if you think it is. I regretfully gave up on that happy illusion some time ago, much as I wish it were true.
What illusion? Gated measurements or ground plane measurements are described in numerous publications and software documentations like the REW or ARTA manual. Of course there are limitations but you make it sound like there's no way to obtain meaningful data other than paying a lab and that's simply not true.
Even data measured in a lab has its limitations. You can probably get more reliable low frequency data from a ground plane measurement taken at an empty parking lot on Sundays than from any lab in the world.
Indeed. They would make a very good low cost 2-way (FASTish) crossed conservatively at around 300Hz. Even the venerable (and otherwise horrible above 300) Dayton DC160 Zaph|Audio would serve well for such a "budget" low end, since the TC9 not only reaches three octaves lower than the dome in the cone-and-dome kit PE used to sell, but it performs better on the high end as well.
Yes, works great in a FASTish system. See post 194 or the "Cheap And FAST OB, Literally" thread, or the Nautaloss thread.
The pronounced null and peaks that show in the manufacturer and vendor data sheets are still missing, even with the "expanded" scale. It will be interesting to determine why . . .
They might have changed it. Rare, but not unknown. I recall Troels Gravesen measured a pair of little ~2 1/2in Scan Speak units with his Clio setup and found them substantially better than the advertised data. Too different for just differences in measurement equipment; IIRC he speculated that the data sheet may have been using the data from prototypes while the production units were modified / slightly revised.
What illusion? Gated measurements or ground plane measurements are described in numerous publications and software documentations like the REW or ARTA manual. Of course there are limitations but you make it sound like there's no way to obtain meaningful data other than paying a lab and that's simply not true.
I have said multiple times that they are useful & provide meaningful data, as well you know. It's there in the posts above for all to read. I have simply pointed out that there are limitations to this as well. Period.
Even data measured in a lab has its limitations. You can probably get more reliable low frequency data from a ground plane measurement taken at an empty parking lot on Sundays than from any lab in the world.
Please present your detailed, peer reviewed evidence showing this to be the case. The acoustic research department at the University of Salford, other such institutions & their commercial lab equivalents will no doubt be intrigued.
Folks of interest, we are at the brink of what can be expected physically from whatever 4" available. Get more - get the throat active with the needed airpush from a compressor - follow evolution...
I can't possibly imagine what that means, but it sounds absolutely filthy.
Regarding home measurements vs lab measurements with "Professional Lab grade equipment": I used to use very fancy microphones and preamps for acoustic measurements in a lab way back in the day. These were Bruel & Kajer, Kistler, etc... $2500 calibrated mic's (just the element), ultra low noise preamps, etc. IMO, what we have access to today for about $70 in the UMM-6 USB mic is perhaps just as good if not better than fancy lab mics because the preamp and DAC sits only 4 inches away from the mic element in the same housing and there is NO noise pickup in the cables, and it is one cohesive unit. It may not be as sensitive or have as wide a dynamic range, but for speaker measurement from 30dB to 120dB SPL, they probably are better than lab gear from 15 years ago. The anechoic chamber is what the home user lacks, and going outdoors can achieve some of that at the expense of increased background noise.
I can't possibly imagine what that means, but it sounds absolutely filthy.
Now, try to get yer most beloved 4" design sound as an elephant with stomach problems...
Regards
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Please present your detailed, peer reviewed evidence showing this to be the case. The acoustic research department at the University of Salford, other such institutions & their commercial lab equivalents will no doubt be intrigued.
Every anechoic chamber has a lower limit. The lower limit of a parking lot is determined by the closest boundary which can be quite far away. It's physics, no peer review necessary.
Now, try to get yer most beloved 4" design sound as an elephant with stomach problems...
Regards
You are giving the Vogon poets a run for their money. ;-)
There is a nice set of measurements of many many subs using the outdoor method that is well documented here: About The Sub Zone: Testing Methodology and Environment - Home Theater Forum and Systems - HomeTheaterShack.com
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