Was a pain in the ass to find since I couldn't remember the name of the speaker, but it was the GGNTKT M1.
Yup. I can never find that thread either. Nobody's remembering a name consisting of 7 random consonants.
Was a pain in the ass to find since I couldn't remember the name of the speaker, but it was the GGNTKT M1.
I follow manufacturer spec in the few rare cases where such is specified. Here is an example from Genelec review:Amir always points the measurement microphone at the tweeter center, S&R takes into account the manufacturer's specifications (as far as I know), which often means that the mic is aligned halfway between the tweeter and the bass-midrange chassis.
The reference axis was as instructed in the manual: the top of the woofer. I also tested it with tweeter axis and it made no difference.
Accuracy error depends on complexity of soundfield, not frequency (not directly anyway). This complexity usually comes about around crossover frequency where multiple radiating sources combine, often with diffraction and other effects. In vast majority of cases though, error is below 1%. Sometimes it rises to 2% and if so, I report on it.If the S&R ground-plane measurements are performed very carefully, they should be superior to those of Amir's NFS in the frequency range above 10kHz, since the conversion of the frequency responses measured in the near field to user defined distances becomes less accurate towards very high frequencies (or needs a lot of data points and time to be accurate up to 20kHz, e.g. 7h measurement for one speaker).
Well, wouldn’t that depend on the room? If you are talking anechoic, wouldn’t all frequencies decrease by 6dB when you double distance?@amirm at what measurement distance are your measurements calculated? Have you played around with different distances? It would be quite interesting to use the Klippel to illustrate how FR changes with distance, as presumably the data for virtually any distance can be calculated from a single set of measurements - is that correct?
That's correct although it is not just one number you modify. It is a large set but I can see if I can modify them all and see what we get. Is there a speaker you want me to test this on?@amirm at what measurement distance are your measurements calculated? Have you played around with different distances? It would be quite interesting to use the Klippel to illustrate how FR changes with distance, as presumably the data for virtually any distance can be calculated from a single set of measurements - is that correct?
What bothers me the most is not the measurements and their differences. It is the attempt to EQ speakers based on measurements whereas other measurements would lead to try other EQ presets.
Hence, the EQ recommendations made here and compiled on this forum can be less pertinent than expected.
We should see two completely flat lines, but in reality, one of my KH-120 is 0.5 dB above the other from 1500 to 3000 Hz, and my two 305P are very different from each other. The stereo image is completely shifted if I swap the left and right speaker, and I should equalize them separately above 1000 Hz.
If you are talking anechoic, wouldn’t all frequencies decrease by 6dB when you double distance?
That's correct although it is not just one number you modify. It is a large set but I can see if I can modify them all and see what we get. Is there a speaker you want me to test this on?
Was a pain in the ass to find since I couldn't remember the name of the speaker, but it was the GGNTKT M1.
I wonder if Genelec measures every single 8351b? Probably not, but if they do, it would be awesome if GLM could use the monitor's serial number and measurements as a part of its equalization algorithm.
I am a bit surprised by the effect on stereo imaging if the shift you mentioned is also true on kh120Here is what remains when I substract a measurement of my left speaker vs the exact same measurement made with my right speaker.
View attachment 110605
We should see two completely flat lines, but in reality, one of my KH-120 is 0.5 dB above the other from 1500 to 3000 Hz, and my two 305P are very different from each other. The stereo image is completely shifted if I swap the left and right speaker, and I should equalize them separately above 1000 Hz.
Well yes they are not directly pertinant IMHO in terms of a direct port.What bothers me the most is not the measurements and their differences. It is the attempt to EQ speakers based on measurements whereas other measurements would lead to try other EQ presets.
Hence, the EQ recommendations made here and compiled on this forum can be less pertinent than expected.
Yes. The room offers free field conditions above 100 Hz.My understanding of German is a bit feeble but might it be they are using a anechoic room instead of a Kippel?
Well, wouldn’t that depend on the room? If you are talking anechoic, wouldn’t all frequencies decrease by 6dB when you double
That's correct although it is not just one number you modify. It is a large set but I can see if I can modify them all and see what we get. Is there a speaker you want me to test this on?
this is also a simplification based on the assumption that the speaker's radiation is 360°. It therefore tends to hold true in the low frequencies, but not quite in the high frequencies
I am a bit surprised by the effect on stereo imaging if the shift you mentioned is also true on kh120
can you elaborate this?
I can imagine that outside of tweeter height the response will vary depending on distance, but you probably are not talking about this.
if we stay at tweeter height we now have a variation in the relative distance to the other drivers that probably will change interaction of drivers in the crossover region (?)