Hello Rob and the Group
--- In Rob Danielson <> wrote:
> Hi Tom--
> I couldn't download the volume matched file but after boosting the
> DIYCaps/Jecklin section +2.6dB and the NT4 section +13 dB to match
> volume, the stereo imaging with your DIY rig is much more interesting
> to me and, if you can rid the buzz (~4K Hz and up) from your DIY rig,
> I'd head out with it over an NT4 any day. Perhaps some shielding on
> the back of the caps or elsewhere would help?
I was monitoring both NH1s from the comfort of my dining room. The
NT4's NH1 was next to me and I therefore used headphones with a short
cable. The Jecklin's NH1 was ouside in the garden and I had to use
headphones with an eighteen ft. cable. Possibly this was a cause of
the hum pickup.
> To my ears, the NT-4's stereo image is very compressed towards the
> center and the cuckoo call with the NT-4 is harmonically simplified
> compared to your DIY Tri-Capsule Jecklin rig. I assume you removed
> the attenuation circuit from your NT-4 cable (if it came with one).
I used NT4 cables that did not have the attenuator.
For this dawn chorus test I used the more sensitive single capsules
rather than the triplets (easily done using a modular mounting system
so that I can use singles or triplets on the jecklin disc and also on
the parabolic reflector). BTW, the reflector is now finished and
operational. The focal zone was found to be very close to the
designed 12.5 cm from the base of the dish. It works well in the
garden but needs testing on the saltmarsh. I will report on this when
it is done.
This evening I did some tests to check the relative sensitivity of the
single capsule and triple capsule stereo setups (in the Jecklin) and
the NT4.
The test was to measure the manual volume setting on the NH1 at which
the bargraph just reached the -12 dB spot. The sound source was pink
noise from an off tuned FM radio 12 ft. away.
The results confirmed the sensitivity ranking and were:-
Single capsule stereo 16
NT4 21
Triple capsule stereo 27
Cheers
Tom
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