hd414 "classic" headphones

[Bob Carlyon <bob.carlyon@xxxxxxxxxxxxxxxxx>]

Some of you may recall brian moore's message informing us that sennheiser
have re-introduced the hd414 headphone for a limited period. I was so
excited that I bought a bunch. We have now calibrated 5 headsets (10
earpieces), and thought that some of you might be interested in the
results. The headphones meet all the manufacturer's specifications, but the
distortion is considerably higher than that on several "old" pairs of 414s
. The range across headsets of second and third harmonic distortion re a 1V
primary (with that seen on one old headset in parentheses), was as follows:

                (* = not measurable)

          2nd harmonic            3rd harmonic
Freq    Atten re primary        Atten re primary
250:       38-47 (66)             33-65 (73)
500:       48-55 (68)             49-73 (69)
1000:      55-60 (72)             67-*  (*)
2000:      52-67 (78)               *   (*)
4000:      33-63 (71)             60-*  (*)
8000:      65-49 (70)             73-*  (*)

Measurements were made using a B&K 4153 artificial ear and a B&K 0.5 inch
condenser microphone, model no 4134. Analysis was performed with the aid of
an HP3562A spectrum analyser, Jay Datta, Christian Lorenzi, and  Minoru
Tsusaki.

And merry christmas to you too.

Bob

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Bob Carlyon
MRC Apllied Psychology Unit
15 Chaucer Rd.
CAMBRIDGE CB2 2EF
England

Phone: (44) 1223 355294 ext 720
FAX:   (44) 1223 359062

email: bob.carlyon@mrc-apu.cam.ac.uk
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