Alpha Audio live stream review of LS1a

Sunday March 28th Alpha Audio did another live stream test of active monitors, of which a recording can now be viewed. The contenders were ATC SCM40a, Dutch & Dutch 8c and Grimm LS1a. In an earlier review a similar test was done, but this time the prices of all three systems were more comparable because the LS1a was used in stead of the LS1be, and also ATC sent in a different model. Next to Jaap Veenstra and Yung Lee of Alpha Audio, singer songwriter Tim Knol was panelist.

A high quality DPA microphone pair was used to record the playback from the loudspeakers. This setup reveals more of the sound quality than one might think (even via the low bit rate codec of Youtube). Listening back to the recording of the stream one can easily ‘AB’-switch between the three loudspeakers, and even listen to the original tracks via your streaming service of choice. For the latter, please make sure to align the playback volume carefully with the level in the Youtube recording. The cue then is to listen for tonal balance: which sound resembles the balance in the original mix most? 

You will hear some influence of the quality of the electronics and processing. The dominant part however is the acoustics of the loudspeaker-room system. You will hear a combination of the direct sound arriving at the microphones first, and then the reflections from the floor, the side walls and the ceiling, and after a while the later reflections from all directions. Together they form the total sound experience. In all loudspeakers the direct sound is colored slightly (by diffraction on the cabinet edges for instance), but the speaker off-axis sound that creates the reflections is usually colored more. The better controlled this off-axis coloration is, the more the sound of the microphone recording will resemble the original. 

Further, you will hear that the balance between the direct sound and the reflections is dependent on the speaker design. It will sound ‘more direct’ with a wide front speaker like the LS1a and more ‘room like’ with narrow front speakers.

Additionally the bass response varies depending on a lot of parameters: the low frequency roll-off of the speaker; whether it is a closed or open system; whether it is an omnidirectional or (partially) cardioid design and last but no least what the relative positions of the speakers and the listeners (or microphones) are in the room.

Read about LS1a >

There is much more to say about this interesting test. For instance how difficult it is for the panelists to compare loudspeakers in such a live setting, without the possibility to directly AB the sound, like we can do now. So don’t judge the speakers quickly, nor the test panel. 

Apart from the live recorded song by Tim Knol, the two tracks that were played are: 

Jacques Loussier Trio, My Personal Favorites, the Jacques Loussier Trio plays Bach – J.S. Bach Fugue in G minor, BWV 578. In the Youtube recording you can find it here: LS1a: 39’19”, ATC SMC40a: 1:09’05”, D&D 8c: 1:47’57”.

James Taylor, Sweet Baby James – Fire and Rain. LS1a: 45’18”, ATC SMC40a: 1:15’16”, D&D 8c: 1:53’42”.