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WAAAYY OT: ISDN woes


mcgoo

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Well, this is not everyday keyboard stuff, but I'm hoping someone might have some good tips / leads / thoughts...

 

At my production studio day gig, we've had ISDN lines for about 15 years, but the use of it is dwindling, while the costs of the lines are going up. We're toying with ditching the lines and going with Source Connect. For the times we'd have to hook up to someone that doesn't have source connect, we'd use a bridging service (thru someone like EDnet), which I think would still be cheaper in the long run than keeping the ISDN lines.

 

So, my questions are- does anyone have any experience with Source Connect, and how performs in VO sessions? As good as ISDN (we've been using the Telos Zepher)? Does bridging to an ISDN studio work ok? Lastly, if you know a forum more suited to this kinda geekdom, point me that way!

 

thanks,

 

greg

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Other than ISDN, nothing else you mentioned made any sense to me. But a local sound guy sets up networks for a major corporation, so I posed your question to him. His response:

I am guessing this is for live recording across the ISDN lines to a remote studio? This is commonly done when recording voice-overs for television shows. More specifically, Southpark used to do it for Chef's voice because Isaac Hayes was in a different city. I am not familiar with Source Connect.

 

If you have to do it in a live scenario, the good news is that T1s are probably cheaper and the difference between a T1 and an ISDN is that ISDN lines have 2 64KB channels and T1s have 24 64KB channels. Carriers are making them more expensive because they want to get rid of the equipment. If you want to nail up a point to point link, it will probably be cheaper and if they offer fractional T1s, it might even be cheaper than that.

 

In scenarios where you do not know where the other end will end up, you might have to go over the Internet. I am sure that this is much like voice over data networks, which I am familiar with, so there are no guarentees as far as quality because the path the packets will take will be unknown. So, packet properties like latency (the amount of time the packet takes to get from the source to the destination), jitter (the difference in the times several packets take from one another--etc. 20ms for packet 1, 30ms for packet 2 and 40ms for packet 3 means 20ms of jtter because the differece between the largest and smallest delay is 20ms) and reliability (whether or not a packet is dropped) cannot be controlled. If it is a stream in real-time, this is going to be sent best effort and if packets arrive out of sequence, the packets that arrived late are discarded. This is why you want low jitter. The better the Internet connection, the less likely you will have problems.

 

If this is just sending a previos recording, best effort is all you need because there is no stream to interfere with. It is just a simple file transfer.

 

Don't know if this helps or not. It can get pretty technical.

 

Dan

 

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Thanks Dan... tell your friend thanks. Yes, we use the ISDN for realtime studio sessions, mostly for recording VO from out of town talent.

 

Since posting this I've been talking to other people. Slowly but surely I'm learning a thing or two. I've heard from others that phone companies are trying to phase out ISDN- it's old tech & they don't have enough techs that know it & can service it, so the price is going up. The problem is that the studio industry has ISDN as the de facto standard, & everyone seems to be sitting back to see what the next standard will be... who wants to dump a bunch of $$$ into hardware or software that won't work with other studios.

 

If we go the Source Connect route, it's an internet based system. I've heard others recommend a T-1- even a dedicated one so we don't bog a line down with other users within the studio uploading & downloading while we're trying to cut VO.... although I wasn't aware of the 24 lines thing. that's very cool.

 

Anyway, thanks for looking into this. It's a real pain trying to figure out.

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We still use ISDN for much of our work. There are many ip codecs and iPhone apps that work well if you have strong WiFi. The iPhone app records to the internal drive and sends the linear file over FTP after the interview/recording is done. The audio sent during the live event is compressed for data bandwidth but is easily replaced. A higher quality interphace and mic to the iPhone/iPad helps a great deal. Using the Verizon MiFi 4g connection is essential if standard hi bandwidth wifi isn't available.
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I had to go through the ISDN stuff about 10 years ago in computer networking. The phone company originally figured it stood for: "I Smell Dollars Now," but even after training, their techs were "I Still Don't Know," and the customers were saying "It Still Does Nothing." The Tidewater Virginia area only had one or two techs with the phone company that really KNEW the stuff to a point where problems could be solved in any reasonable length of time.

 

If an ISDN circuit was doing the job, even business grade DSL connection should work, or cable broadband if that is available. Fractional T1 is point to point, so the bandwidth is always there. In many areas, trying to get a T1 or fractional has a long lead time.

 

The studios do need to figure out a new pathway. The ideal would be something that digitizes so that the result can be processed by any of a number of different technologies, so that communications becomes independent of the specific physical layer of communication.

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The key with ISDN is knowing your codecs well and the choices that clients make. For instance, the BBC still likes G.722 when we use L2mono128 for most circuits. The L2 gives better frequency response and lower latency. Music vs. speech have differing requirements. Live vs. taped interviews do as well.

 

ISDN will be phased out over the next few years. Comrex and other devices will give you great performance as long as internet traffic isn't congested.

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To be honest, I thought everyone had moved on to other technologies beyond ISDN years ago.

 

I have a computer wiz / Network designer buddy that got a good laugh 5 years ago when I told him we used ISDN. But it's not that we're alone. If that were the case it'd be a no brainer. As far as I can tell, most pro studios that do VO work & use out of market talent still use ISDN, so the problem is, everyone's afraid to jump ship until a clear leader emerges. Right now it seems there's no universal software or hardware that'll work with anything. There are bridging services that are making it their business to have lots of different technologies, so that people can go thru them to get hooked up to another studio using something else. Of course if a clear leader (hardware or software) emerges, eventually they'll have to revise their service line, but that's not my problem. :)

 

So far, I've heard people mention Source Connect- it can run as a VST right inside my DAW to hook up thru the internet. It would hook directly to another studio if, and only if they also have Source Connect. If not, then I go thru a bridging service. What I haven't found yet (other than testimony from a bridging service) is how well that works.

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The building my former employer uses I "discovered" about 4 years ago that by changing their phone service to the local cable company they could double the lines in and get improved internet bandwidth at the same cost as using the local phone company and ISP. They needed more server bandwidth than the T1 could provide. So I made some inquiries, turns out we had a fiber connection to the building, installed previously by other businesses in the building. So by switching to fiber we went from a standard T1 1.5Mbs speed and 10 ISDN lines to 5Mbs and 20 phone channels at the same cost.

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