Pro Audio Design Forum

JR. wrote:but their target market was live and fixed instal not recording. The APB design team was responsible for Crest consoles, and several years after Peavey bought Crest, they left and formed their own console company.

That makes more sense. Like you said, in the past five years plus I've never seen an analog console at a club be replaced with another analog one. Everyone is putting digital consoles in clubs.

Yes, it's becoming rare to encounter an analog console in a live setting. I've also discovered how much fun it is when a digital console freezes mid show and needs a reboot, I've seen Yamaha's and Presonus do it.

Another "live" app I'm pretty familiar with is television broadcast, such as the 10:00 news shows. The TV stations were dragged into the digital era when the Feds killed analog over-the-air broadcasts.

More than a few times I've seen the audio (and other times the video) lock up during a newscast...something that an old ADM, Ward-Beck, etc desk would never do, nor a Grass Valley/whatever video switcher.

Bri

Going back to the original gist of this thread. Regardless of what's in the middle of the signal path, we still have to deal with analog inputs (mic and line) and audio outs.

The former requires input switching and preamps in the case of mics. The latter often times requires analog routing.

Bri

brianroth wrote:Going back to the original gist of this thread. Regardless of what's in the middle of the signal path, we still have to deal with analog inputs (mic and line) and audio outs.

The former requires input switching and preamps in the case of mics. The latter often times requires analog routing.

Bri

Increasingly we are ending up in the digital domain, so analog middle ware becomes a decisions of how soon after the mic preamp do we make the conversion?

There was an expectation that we would end up using digital output mics, and that still could happen, but old shool analog mics are not going away anytime soon so analog mic preamps will stay with us for a while.

Digital controlled analog mic preamps seems like a part of out tool kit for a while.

JR

As does "after the fact" routing to things like loudspeakers, outboard boutique gizmos, etc.

Bri

JR. wrote:There was an expectation that we would end up using digital output mics, and that still could happen, but old shool analog mics are not going away anytime soon so analog mic preamps will stay with us for a while.

With my mike designer's hat on ..

I like to have my mikes behave up to 135dB spl and die gracefully above that.

I'd be very happy to have a noise floor of 10dB spl like some of the Sennheisers. So a dynamic range of 125dB.

There are quieter specialist mikes and my Calrec Soundfield Mk4 does 145dB quite nicely with Vp switching but I think most designers of high quality recording mikes would be happy with this performance.

This compares with the 20b performance of the best A/Ds which nea...arly reach 117.4dB [*] So we are some 10dB away from a fully digital high quality mike.

Panasonic made an experimental 24b A/D which Guru Scott Wurcer has tested for true 141.5dB DR but it was declared unmanufacturable. I think 20b performance on 24b A/Ds is likely the best in 'real life' for the forseeable future. There's loadsa analogue details that have to be addressed at a very high level to do this.

[*] The DR isn't just 20b x 6.02dB. The real comparison is a FS sine wave with the properly dithered TPDF noise. See Lipsh*tz & Vanderkooy et nauseum on dither. They show some dither tricks to improve on this but in practice, the best 'real life' A/Ds are still 20b

Speaking of hybrid systems...

One project I recently looked at was a post-DAC, pre-power amp analog attenuator for live performance applications.
DSP-based attenuation followed by a 124 dB DR converter (if you can actually get that much DR) just didn't cut it.

In DSP-based digital wireless mic applications getting signal into the A/D unclipped without some form of analog protection limiter/companding would seem to be a challenge.

And of controllers...

I just contacted THAT to get a firmware upgrade for the USB/SPI interface so that the DLP-232 can be used with the 5263 dual gain controller.
Not being happy with the Win-based USB interface they built up an Arduino SPI controller with two analog pots controlling the SPI commands.
They wanted something "intuitive" like a knob.
That's the kind of gizmo I'd like to see posted here.
I should be getting details on it soon.

And finally digital broadcast facilities...

I have a friend who is the Director of Engineer for a popular nationally syndicated morning show tell me about the day the Wheatnet router crashed during morning drive.
Tens of thousands of dollars in ad make-goods, thousands of dollars of loaner replacement equipment and hundreds of dollars in Fedex charges it was discovered that an RJ-45 had backed out of its socket.
The modern digital broadcast plant can be a very fragile thing.

Analog gear can suffer single point of failure modes too... While a highly computerized digital system may be harder to patch around in limp along mode.

My comment about digital mikes not being popular any time soon was more related to "flavor" preferences than some dynamic range conversion limitation... analog media has dynamic range challenges too.

Some have played games with intentional non-linearity at the top of the dynamic range before conversion to add some soft-limiting to extend effective dynamic range. Midas digital consoles have some fan-boys who apparently prefer to hit the (soft) limiting hard and often.

For wide dynamic range digital controlled analog, I would investigate DPOTs (try lower impedance models), but the PCB implementation could affect noise floor from digital leakage, For set it and leave it alone, the digital clocking could be turned off and noise floor should be pretty good. While during gain changes, noise floor would be harder to guarantee.

JR

JR. wrote:Analog gear can suffer single point of failure modes too... While a highly computerized digital system may be harder to patch around in limp along mode.

JR

In the broadcast systems I helped design (or reverse engineer <g>), single points of failure were extremely rare.

Redundant power supplies, battery backups...even generators ...covered the most common failures. Multiple buses and Olde Fashioned patch bays in the equipment allowed 'routing around" a failed signal path.

The Digi systems either work 10000% correctly, or are in total failure. In my experience, there is NO "limp along".

My fave joke: "Wanna Hear me copy the sound of a locked-up digital circuit/digital path: dadadadadadadadadadaddadadaa"



But, I am digressing from the gist of this thread. I ACCEPT that these digi systems are fragile..."Brian...get used to it".
lol

(Just like I hate the half-second (?) latency delays when in a fast-paced conversation on a cell phone.."OK..OK...Eric...you talk and I'll be quiet".) Ma Bell landlines didn't mess with me like that! <g>


Ahem....onwards into the future, such as it is...

Bri