PDA

View Full Version : Dave, how about a shootout


audibleconnoisseur
05-31-2007, 08:13 AM
Dave, can you put up a thread that has the decay of S-1 v/s 340SE? Specs of one v/s the other? Interested to see at what % the S-1 are an improvement. Possible to do this for us? Interested to see the visual representation of the measurements side by side.
curtis
05-31-2007, 08:20 AM
a CSD graph for both is available:

CMT-340SE
http://www.ascendacoustics.com/images/products/speakers/cmt340m/340SE_CSD.gif

Sierra-1
http://forum.ascendacoustics.com/images/ascenduploads/CSD.gif
Quinn
05-31-2007, 08:20 AM
Pretty easy to cut and paste them into a post.

340SE-
http://www.ascendacoustics.com/images/products/speakers/cmt340m/340SE_CSD.gif

Sierra 1-
http://forum.ascendacoustics.com/images/ascenduploads/CSD.gif
curtis
05-31-2007, 09:21 AM
Too funny...we posted at the same time!
dallas
05-31-2007, 09:46 AM
can anyone authortatively explain why CSD graphs have no data plotted in the lower left ? i.e., low frequency vs high time
Quinn
05-31-2007, 10:23 AM
Well not authoritative but, I think you run into ground plane issues and need an anechoic chamber to measure below that point.
BradJudy
05-31-2007, 11:57 AM
There's some math (that I can't quote without digging up reference material) about how the amount of time you can measure (msec on the right axis in these images) varies with frequency. Essentially, as the frequency lowers, the time window shrinks, which displays as that cut off in the corner of the graphs.

If the graph was expanded to show a bigger time window, you'd see that cut off curve of no data arcing into higher frequencies.
dallas
05-31-2007, 12:03 PM
There's some math (that I can't quote without digging up reference material) about how the amount of time you can measure (msec on the right axis in these images) varies with frequency. Essentially, as the frequency lowers, the time window shrinks, which displays as that cut off in the corner of the graphs.

If the graph was expanded to show a bigger time window, you'd see that cut off curve of no data arcing into higher frequencies.


seems like a reasonable answer. It' just bugs me there is data that lies directly against the line, and one would assume on the other side of the line that is not getting recorded.
Quinn
05-31-2007, 12:14 PM
seems like a reasonable answer. It' just bugs me there is data that lies directly against the line, and one would assume on the other side of the line that is not getting recorded.

It is recorded but it isn't accurate. Brad did a fuller explanation then I did. My understanding is the low frequencies are really close together and it is hard to gate out the reflections with how fast they arrive.