Dick Pierce wrote:
Peter Larsen wrote:
Hi guys,
see http://muyiovatki.dk/yorkville/
comments appreciated, is the 4 Ohm box broken?
Looking at one of many assertions made on the web page:
Thank you very much for the careful explanation of what can cause a "4 ohm
version of the same bass loudspeaker unit" to be less efficient, I have
altered the text on the web page in accordance with the points made.
I'd be quite surprised if these two system had even
approximately the same efficiency: if they did, I'd
bet the the 8 ohm one was the broken one.
Consistently 6 dB more sound is produced by the 8 ohm box compared to the 4
Ohm box.
Another comment: the frequency response curves seen on the
site are , well, pretty awful, and it's mostly because of
poor measurement technique, not because of intrinsically
bad response. The curves show tremendous amount of interference
artifacts and more, and it's difficult to derive any
meaningful results from this data.
Output under given conditions was measured, not frequency response per se,
it is not possible to make a valid frequency response of a large speaker in
a small room.
This is not a flat out criticism of whoever made the measurements
per se, but atests more to the fact that measuring speakers
properly is DAMNED hard to do. Measuring them well repeatedly
across several samples is even harder.
No contest.
One and/or the other pair may well be broken. The difference
in efficiency itself is no indication of some problem. But
I'd be hard pressed to declare which was broken, if any, from
these measurements.
Could well be that they are just a pro version and a toy class version of
the same speaker concept, currently I am waiting for comments from
Yorkville. It will be interesting to see whether DHL actually has lost the
second of the PL315/4's or they find it ...
Kind regards
Peter Larsen