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RTA comparison on vintage speakers

Your "8 speaker comparison" would be much easier to interpret visually if you turned off the data point symbols.
 
BmWr75 said:
Two more vintage speakers and a remeasured AK design have been added to the 8th post in this thread.
Click to expand...
I'm calling your work with these "Commendable."

It clearly demonstrates that with relatively inexpensive measurement gear and some knowledge and practice, you can easily ascertain the frequency response performance characteristics of a variety of speakers, and distinguish among them.

Your results correlate well with my own findings on those particular models which I have also measured, and I fully expect we'll see further validation of your results as more AKers get up to speed with objective performance assessment technology.... :thmbsp:
 
BmWr75, thanks for the measurements.

Re the DEQ2496, I would suggest taking images in "full screen" mode. Press "RTA" and toggle RTA display to full screen. Much easier to read and compare.

Question:
Are your results of one monitor or the stereo pair?

Reading RTA of the pair makes precise hairline accuracy of the mic position essential or HF cancellations will show.

I usually do a single monitor at one meter.

So far in my experience, the floorbounce, which may be the 315 Hz anomaly someone mentioned earlier, can be mitigated by generous acoustical damping, but not eliminated. I try to keep the ceiling in mind as well, so the height is a factor.

I can tell you from personal experience that the ECM mic is not consistent in its FR (tried 3 of them), so I correlated my measurements with those of "known accuracy," such as Zilch's. But that only ball parks the questionable range. I know of no way to use a calibration file for the DEQ unit.

On the other hand, I find that I can duplicate my measurements exactly so long as I know the exact placement of the speaker.

It's a cool unit and does a lot for the money.
And thanks again!
 
skywave-rider said:
Question: Are your results of one monitor or the stereo pair?
Click to expand...

Single monitor. Just used the balance knob to shut off the other speaker.

I do always mean to take the photos in the full screen mode, but see I've forgotten a few times to do that.
 
Zilch said:
Well, poo. :pity:

Try it both ways and let's see what you get.... :yes:
Click to expand...

Zilch, here you go. Just remeasured the OLA utility cabinet with the grill on and off. Tweeter switch set to Normal. See the attached pictures. With grill is shown first. Without grill next. The grill on smooths out the curve.
 
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Yep, I already suspected that curve was the basis for your "no grill" guess. I didn't remove the grill when I made that earlier measurement, so was probably measuring below the tweeter. Had to adjust the mic stand up for the most recent measurements.
 
It's all instructive, of course, and I'm not a bit embarassed by any of it; the data is what it is.

The appropriate question is always, "HEY, what's up with THAT?" which frequently leads to new discoveries, and I'll follow up on this one, later today, perhaps. :thmbsp:

I still haven't figured out why they don't image worth a poop, and you may be on to something relevant to that issue here.... :dunno:

Edit: http://www.audiokarma.org/forums/showthread.php?p=2526351#post2526351
 
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