That poor RAAL ribbon, it produces a lot of compression (and interestingly the 10kHz region is the worst), along with the SB Acoustics woofer. Is that normal for true ribbon tweeters?
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Given the weird choice of components it seems to perform reasonably well. A short ribbon on a flat baffle will have limited SPL as will a 6" midwoofer. The speaker is too small to be used as mains in a typical room for standard levels and is a bit big for desk use. The compression business is simply reflecting the physics that it is a small speaker. If one listens quietly or sits close it may be fine. A good example of an interesting quirky DIY(ish) speaker.
I have also did some compression testing for (dome) tweeters, and it turns out the usual testing may not be representative of performance effects in real life musical content or recorded program material.
For starters, the test results are strongly dependent on the duration of the test signal. Let me find my thread and link to it here: https://www.diyaudio.com/community/threads/high-dynamic-range-104mm-dome-tweeter.386061/
If don't want to read the thread, here is my summary- I posted a thread looking for a tweeter that can hit over 106dB @1m. For the moment, let us put aside whether X dB is enough for you or me or a crowd at 10 meters, I just wanted to see which was the limiting factor for my design- was it the woofer, the midrange, or the tweeter?
So I went off and did high voltage testing to check. 2.83V, 8.95V, then 28.3V (in 8 ohms that 1, 10, 100W OR 0dB, 10dB or 20dB gain).
Here are the results- the tweeter did not do very well. And it turns out it's strongly affected by the duration of the test sweep. Don't ask what happens when you do a slow sine sweep through a tweeter- because it's lets out the magic smoke!😱
We must remember that musical content has a) very little content above 10KHz b) whatever is there, it happens as short sharp bursts.
As for the bass, this is a thing with the SB Acoustics standard line. @Zvu has been pointing out the relatively poor sub-bass performance of the SB standard line for a while, whilst others say they don't hear it. Well this is good evidence that you may indeed here it, because there is ALOT of content between 50Hz and 300Hz.
Dennis' original design, with the lower sensitivity, but high excursion evergreen Scan-Speak 18W/8545 is still available as a kit via Meniscus, by the way.
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I watched that last night..
Notably there is a point where Erin mentions that loudspeaker has better sound-source localization in the room down-stairs vs. up in his HT and believes the difference is because of room side-wall reflections in the HT room. Likely in part to some extent, however..
My guess is that it has more to due with diffraction effects relative to listener distance. The closer you get to the loudspeakers the more diffuse the apparent "image". In his large room down-stairs he can sit *further away from the loudspeakers and the apparent source-width of the diffraction effects decrease typically leading to a bit more "pin-point" imaging. Often the angle of the loudspeakers relative to the listener is greater as well, and this can also impact image localization.
*I don't know if he did, just a guess. (..as this has been something I've also experienced.)
Notably there is a point where Erin mentions that loudspeaker has better sound-source localization in the room down-stairs vs. up in his HT and believes the difference is because of room side-wall reflections in the HT room. Likely in part to some extent, however..
My guess is that it has more to due with diffraction effects relative to listener distance. The closer you get to the loudspeakers the more diffuse the apparent "image". In his large room down-stairs he can sit *further away from the loudspeakers and the apparent source-width of the diffraction effects decrease typically leading to a bit more "pin-point" imaging. Often the angle of the loudspeakers relative to the listener is greater as well, and this can also impact image localization.
*I don't know if he did, just a guess. (..as this has been something I've also experienced.)