Hi All,
Thank you for the prompt reply. Here's some feedback:
@Purité Audio - yes, the microphone position was identical for all speakers (ear height, exactly at my listening position), and so was the tow-in of the speakers. The speakers were practically in the same locations - there might have been few cm difference between them, but pretty much within the same floor markings.
Maggies measurement appears to be horizontal but if you draw a trend line through it, there is approx. 6dB difference between the lows and highs, and this was my intention. I'm still experimenting with different Dirac target curves. The current one gives very balanced sound, but it lacks a little impact in the low frequencies.
@YSC - Yes, anything below 500Hz or so is predominantly the character of my room, but it is still interesting how different speakers in the pretty much same position load that room.
Other than the Magnepan measurement, no subs were used with any other measurements shared. Similar drop off in the low bass frequencies can definitely be attributed to the room gain, especially that all measurements were conducted with speakers being pretty much in the same position.
Yes, I've been using Dirac to correct the whole frequency spectrum, not just below 500Hz. Magnepans in my room are slightly too bright, so before I had access to MiniDSP I've been using them with 1Ohm resistor on the tweeter. After purchasing MiniDSP SHD I experimented with achieving same slope using Dirac. I've compared the two methods of reducing treble output and I could not really hear any difference between them. As such, my thinking was that if I am using Dirac to correct the bass, I may as well use it to do the full frequency range and not bother with the tweeter resistors.
@Chrise36 - When I do room measurements, I always place the mic in the same location (my ear height at my listening position). With ATCs being on the floor, that places the mic just below the tweeter, which is above the acoustic centre of the SCM40A. Just bear in mind that at the distance that I measure that worked out to be around 3.5°, so definitely within the claimed vertical dispersion of +/- 10°. Moreover, I've tried lowering the mic and playing with the speakers tilt, and the slight hump above 5kHz was still present.
I only run Dirac for speakers that form my system, so I don't have it for any other measurements I've shared - sorry. With Dirac, you can pretty much make the FR look however you want, so to make it comparable, I'd have to use exactly the same target curve for each speaker set, and that may not always be desirable. I've only shared the post-Dirac measurement of Maggies, to give you an idea of what frequency balance I'm used to from my main system. Comparing that to other measurements wouldn't be fair.
The Magnepan 1.7i measurement with subs and Dirac was provided for reference because this is my main setup. Midbass is around 40hz to 80Hz, and these frequencies are predominantly covered by active sealed subs in my setup. In my experience, Magnepans don't have as much attack as electrodynamic speakers in the upper bass to midrange, but as with a lot of things in HiFi, it's a compromise that I am willing to live with.
ATCs were played to around 93dBA at 2.5m distance with music material. They did not sound comfortable above that level. Overall, they did not give me an impression of effortless sound that I experienced with some other speakers. Just bear in mind, it's all subjective so my experience may be completely different to yours
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@goat76 - thanks, it takes a lot of time to take half decent photos, and even more time to write your impressions!
It's interesting how lack or excess of different frequencies can be described in different ways. Are you able to share your gated measurements? Also, have you done any in-room measurements - it would be really interesting to see how they compare to mine.
And speaking of measurements, although I really enjoy learning and understanding what's going on, you need A LOT OF measurements to be able to draw conclusions about whether something is likely to sound good or not. Even with spinorama, you may be able to filter our really bad speakers, and have more confidence about which ones your are
likely to appreciate, but that won't 100% guarantee that you will like something. I think it's a great guide and I wish all speaker manufacturers had access to Klippel and were publicly sharing their spinorama results. I think that with the academic research conducted in the past decades, we're definitely moving in the right direction. However, in my opinion, we're still long way away of having high degree of confidence that if something measures well we are going to like the sound, and vice versa.
All the best,
Shem
