Studio monitors might be a slight exception since the direct sound is very important and I could see someone wanting to place them perfectly for that situation. I'm referring more to home setups where most of us place speakers somewhere close to tweeter height at ear level. Now as long as the reference axis is specified to be somewhere between the midrange and tweeter axis then sure go ahead and use the manufacturer's recommendation, my problem is specifying something that isn't a normal use case just to produce a better graph. My example of the M126 be is the only speaker I've seen that deviates from somewhere close to the tweeter axis and in that case I would measure along the tweeter's axis because that is more accurate to how people will be using them. Revel also specifies that they be placed with the tweeter near ear height in the manual, so it's odd that they want them measured 7" above the tweeter. So I say if a manufacturer specifies a reference axis then use it, otherwise just pick something like the tweeter axis to be consistent.
And no we should be measuring all around the speaker but people who don't listen on-axis can safely disregard the On-axis curve and focus on the listening window, which is much more useful for most of us.
Do not disagree with any of this. The reason the reference axis was in contention with the Neumann was that it is very explicitly specified in the manufacturer instructions, and it is not at all an unusual location =]
You're right though. General procedure is to measure at the tweeter axis unless otherwise specified. Where things have sometimes gotten complicated for me is when the tweeter is placed asymmetrically on the baffle.
Actually, we have two other measurements : the one from Sound and Recording, and the one from the member ctrl.
The curve from Neumann is not a measurement of an existing device, that they took as it is and put into their measurement jig, and found that it measured flat.
They created the device: they put a prototype into their measurement jig, got an average curve, and then tweaked the design, then got a new curve, then tweaked something else in the prototype etc, until their measurement says its flat. And the KH-80 was born !
The frequency response that they provide is obviously from the same measurement device that was used to make the prototype measure flat. It is the frequency response after they have tweaked the speaker so that it looks ruler flat according to their own measurements.
I still think this is a very bizarre argument =] Aside from what
@thewas_ said, it doesn't really matter if their measurements are flat because Neumann were aiming for flat.
A
myriad of good speaker designers aims for ruler flat, especially pro products. I mean, that's what JBL is doing too in their monitors. So why aren't JBL's monitors as flat in their own measurements until you get to the M2? After all, they
created the speakers. Shouldn't the 305P and 705P be flat too?
You could argue that that's because they wanted to save their best for their most expensive, but if so, that's another thing I appreciate about the neumann - the KH80 is actually their flattest speaker, despite being their cheapest. So that reasoning wouldn't hold.
(Edit: to be clear, it's not like I think being 100 percent flat even matters that much! It's about the discrepancies).
Point is, it's not that hard to make a speaker with a perfectly flat on-axis graph. All you need to do is some basic EQ in DSP. Make yourself some filters in REW. If manufacturers wanted to show a perfectly flat line on-axis, they could all do this. They don't(usually), because major deviations would show up in independent verification.
Moreover, the Neumann measurements are independently verified by sound and recording, and arguably my own. Though my measurements don't have quite the same tolerances because they were measured in a living room with three animals sometimes running around (lol) and the gate and splice method, they show the same low-Q tendencies.
Which as
@edechamps pointed out, is crucial. I want to be clear that
this is what those of us with concerns about these measurements were worried about before we learned about the SPL levels and reference axis. I doubt anyone cares about tiny differences like whether this line is more squiggly than that. That doesn't affect sound quality and can easily be explained by equipment, noise, procedure, tiny reflections in your setup, etc (within reason). It's the
low-Q deviations that stood out to those of us familiar with this speaker because those would be the most audible issues.
Just seems weird to imply that just because a manufacturer provided a frequency response graph, it can't be accurate or useful or reliable . Obviously sometimes it's not, but we have no reason to believe that's not the case here - it's been independently verified.
Anyway... I'm glad we finally have another speaker to move on to
. And I really appreciate Amir is taking the level issue to heart, as was noted in the new JBL 104 review.