Blueamps C112

    Thanks for the reply and the information!


    It does look like the speaker has significant non-linearity. In particular, the dip at 2Khz would make the speaker "darker".


    I do agree with your statement on phase .... to a degree. Nearly all modern DSP controlled powered speakers handle the phase shift associated with filters needed for cross-overs. This is really only an issue with passive speakers that are bi-amped these days.


    One other thing to consider is that frequency plots are performed at a single output level. At different output levels, the plots can look (and usually do) quite different.


    Finally, you can't really state:

    Quote

    the Camper 112 is flat from 97-10.500 Hz (-6 dB) and 130-8.500 Hz (-3 dB).


    -6db is 1/4th the output (-3db being half). Flat would be no deviation from zero. Now, no speaker is completely flat mathmatically, but stating -6 and -3db points as being "flat" is simply incorrect.



    Some manufacturers state something similar to this as "the frequency response". If they want it to look better, they use the -10db points.


    Do you have a graph of db SPL vs frequency? This would then let us know the SPL that the speaker was measured at.


    As an example: http://www.jblpro.com/ProductA…ents/JBL_PRX612M%20v8.pdf


    JBL has measured the PRX612m at 100db SPL. This is also kind of misleading IMHO (although at least you know more of where the numbers are coming from). Most people don't play live at 100db SPL @ 1M. This would be quite a bit below rock band levels since the output will decrease from 100db as 1/distance ^2. While 100db is a good level for a club IME, you aren't going to find many of the audience hanging out with their heads 3 ft from the speaker ;)


    At higher SPL is where better speakers are separated from ..... less good speakers.


    There are new DSP technologies being used. Yamaha uses what they call FIR tuning. What it is in common speak is a dynamic frequency response shift. Since the human ear does not HEAR all frequencies with the same sensitivity and all volume levels, Yamaha attempts to dynamically adjust their frequency response curve as the volume levels change throughout the frequency spectrum.


    It sounds complicated, but for those using the DXR/DSR series speakers ..... there is no denying the quality of the result.


    .... I have a gig tonight, but I guess a little engineering work before a gig is good for the soul ;) Monday it will be back to being an engineer full time again!


    Thanks again for the detailed feedback.

    Quote from OneEng1

    It does look like the speaker has significant non-linearity. In particular, the dip at 2Khz would make the speaker "darker".


    Are you serious?


    There is no BlueAmps or Camper which uses DSPs. Our crossovers are analog. ;)


    The Camper 112 was measured the way the most people do: 1 watt at 1 meter. 99 dB.


    PS: Some other manufacturers use -16 dB points and don´t show plots to the public. So I think our datas are okay. 8)