External Audio DSP usage

Robert KB6QXM

Has anyone used an external audio DSP from the audio out of a Flex 6XXX radio? I have a JPS NIR-12 that I want to feed a set of Altec Lansing powered speakers/subwoofer.

Thoughts?

Patrick

I use a bhi DSP, would not be without it now, really improves noise abatement.

Mr Radio

I am using a Timewave DSP-599zx. It provides a very pleasant audio, unfortunately one audio channel can be used at any time.

Robert KB6QXM

@Mr Radio My thought is to use a cable splitter at the end of the chain. You end up with dual mono audio anyways.

Mr Radio

OM Robert,
Timewave has two channels but they are selected by a switch and only one channel can be used at any time.
I had the same idea like yours, but it did not work. Anyway, I am stiil using it with my Flex 6700, it provides a nice sound for one channel and some adjustments are possible.

Tom, SP7WT (Mr Radio)

Doug Hall

Robert,

I have some experience with the NIR-12 as I designed the hardware and wrote the software for it back in the 1990s.

The bandpass filtering on the NIR-12, while quite good, will have a disadvantage over the filtering in the radio because it happens at audio, while the filtering in the radio happens earlier in the chain and is ahead of the AGC. In other words, the NIR-12 will filter out the undesired sound, but the radio filtering will filter out the actual undesired signal.

You might get better results with the noise reduction modes and the automatic notch filter on the NIR-12, as I have found that these modes in SmartSDR are not exactly stellar.

73,

Doug K4DSP

Robert KB6QXM

@Doug Hall Nice to meet you. I think that the JPS NIR-10 and NIR-12 are outstanding pieces of hardware. I also own a JPS ANC-4 also. JPS equipment was stellar in my opinion. It is a shame that they no longer serve the amateur community. The last I heard the company still serves the military.

In reference to the NIR-12, I want to tailor the audio going to my amplified speakers/subwoofer. Between the radio and the external audio DSP, I might be able to get the experience that I am looking for. Can you tell me what was the last firmware version of the NIR-12?

Thank you for chiming in. I checked out your QRZ page. I will personally let you know my experience once I get the cabling I need to wire it up.

73

Doug Hall

Robert,

There was never any updated firmware for the NIR-12. So you've got the latest version.

JPS is still around, and serves the land mobile radio market selling interoperability equipment and signal-to-noise voting systems.

73,

Doug K4DSP

Robert KB6QXM

@Doug Hall I also own a JPS NIR-10 and I know that that there was multiple releases of that firmware.

Thank you for the reply. I appreciate. I will not have to open the NIR-12 now to look at the firmware version.