The LM-1 vs. Bruel and Kjaer

The LM-1 speaker kit has only been promoted for a little while and already it's evident there's a lot of misinformation and attempts to discredit the design. I hope it doesn't become the Kardashian (any of them) of speaker kits.  In any event, one completely inaccurate criticism is that the frequency response is below-average. Nonsense. Could you use different parts and asymptotically approach perfection? Probably. You could get different, but getting noticeably better will be very difficult.

Let's go over some background.

Who is Bruel and Kjaer?

When scientists and engineers think of high-end acoustical instruments Bruel and Kjaer is among the most respected names there is. One famous bit of knowledge that has come out of that organization is the ideal B&K speaker curve, which I happen to like a lot (that's a personal preference). It is meant to be as the ideal response at the listening position. I copy it here, below:

Note that it is not flat! A speaker that measured flat at the listening location would be an ear drill. The B&K curve is about +3dB at 70 Hz or so and -3dB at 20 kHz. Quasi-anechoic measurements measure the speaker driver in near-field, with the expectation that at a distance the measurement would become like you see here. The full discussion of why this is beyond the scope of this posting, but do your research and you'll find much more written about it. You may also find that the Dirac Live target curves, also follow the B&K model of a gently descending response. The point is, I don't make this stuff up. Flat at the listening location is not actually ideal. What is ideal is open to some interpretation.  I'm choosing the B&K curves as a matter of taste.

So, how does the LM-1 do by comparison to this fabled B&K curve in real life? Let's comapre (LM-1 level is offset and measured in a bookshelf):

Damn well! This is the plot with R1 = 4.2 Ohms (2.7 + 1.5 actually). I'm packing and that's all the resistors I have on hand.

So, what does this say? This is an objectively neutral speaker kit. If you are looking for a true bookshelf speaker system with reference grade frequency response the LM-1 will do it for you, within the limits of what a small monitor can do.  Also, as discussed, the treble balance is up to the builder. If you don't like it, change it. :) I have a feeling that most listeners will like a value closer to 3.9 Ohms or so.