The EQ settings were flat on both radios. Actually, there is no receive EQ
setting in the TS-870, and the receive EQ on the O2 V.2.037j does not work
on AM. Each receiver was fed to a Behringer UB1202 mixer (settings flat)
feeding a Sound Blaster Audigy 2 card in my laptop, also flat.
On your graph Martin, is the vertical axis time? If so, how much time is
being displayed? I'm not quite sure how to read that.
Ron N6IE
www.N6IE.com
(Formerly N6AHA)
----- Original Message -----
From: "Martin AA6E" <aa6e@ewing.homedns.org>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, January 23, 2007 5:53 PM
Subject: Re: [TenTec] AM Receiver distortion in Orion II
The second half is clear far better than the first, in my opinion. It's
not a question of low-frequency response, but of distortion in the highs
- almost like a little clipping, or maybe some other digital artifact.
Ron should tell us what the Audio Eq. setting was, by the way.
I ran a spectrum on the file with Spectrum Lab. The results (for
several playbacks) are at http://aa6e.net/aa6e/images/capt0701232044.jpg
. Carl was right that the "good" playback is much wider than Orion's.
Orion's spectrum has a very sharp cutoff, but I don't think that's what
I am hearing.
It would be neat to try this on the Orion I comparing v1 and v2
firmware, but I've got a few other things to do right now...
73 Martin AA6E
Carl Moreschi wrote:
The Orion recording has more bass and less highs. With a 6 khz filter in
the Orion, the audio passband is 3 khz on each side of the carrier. I
would
expect this to sound bassy and have less highs. But the quality is
excellent. The 870 recording clearly shows that the bandwidth is much
greater than 3 khz which would only allow 1500 hertz of each side of the
carrier. I bet the 870 has a special AM filter that is in the 9 khz or
higher range that switches in automatically in AM. It is impossible for
the
870 AM audio to sound like this with only 3 khz BW. Both audios are
excellent considering the BW.
Carl Moreschi N4PY
121 Little Bell Drive
Bell Mountain
Hays, NC 28635
----- Original Message -----
From: "Ron Castro" <ronc@sonic.net>
To: "Ten Tec List" <tentec@contesting.com>
Sent: Tuesday, January 23, 2007 5:54 PM
Subject: [TenTec] AM Receiver distortion in Orion II
One of the items on my "wish list" for the Orion II is to fix the AM
receive audio, which sounds to me like a problem in the DSP code that
causes
distortion and 'muddy' sound. It's most noticeable during selective
fades
that cause a serious clipping effect. Last night, I made an MP3 of a
local
AM radio station comparing the O2 to a TS-870, and sent it to TT service.
This morning, TT said they couldn't hear any difference between the two
receivers. Is it my ears or what? The link to the clip is below. The
O2
is the first 60 seconds and the 870 is the second 60 seconds. Bandwidth
on
the O2 is 6 kHz, while the 870 is 3 kHz, although as you'll hear, it
sounds
just the opposite!
http://n6ie.com/OrionII_vs_870.mp3
Can anyone besides me hear the difference?
Ron N6IE
www.N6IE.com
(Formerly N6AHA)
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