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 1 
 on: Today at 10:42:08 am 
Started by scottstephens - Last post by John Roberts {JR}
Bozak should be more famous/infamous.  He's one of the departed audio pioneers I wish I could have met.

Paul Klipsch is another...
I was lucky enough to work with him as an outside consultant (designed electronics for a couple consumer delay products). I got to become friends with Rudy and after he retired he even drove up to where I lived (above Hartford), to have dinner, with him and his wife. He sold his business and retired when he did, because he had a brain aneurysm that was inoperable, and he didn't have a child capable to take over the business. 

I tried desperately to get one magazine editor to interview him while he was still around. Rudy was one of those guys who has forgotten more than I will ever know about speakers. I offered to have the interview at my place which was half way between the magazine office and Rudy... The editor dragged his feet and that window closed (RIP). In hindsight I should have interviewed Rudy myself, but we all know how hindsight works (too late to fix anything).

For any generation there are a handful of pioneers who think outside the box, and advance technology. I would put Tom Danley on today's shortlist, but there are a few more. Our industry is not very good about documenting and showing respect for the greats because this is a business after all. 

Thanks for the opportunity to remember an old friend.

JR 

 2 
 on: Today at 10:40:52 am 
Started by Scott Gaines - Last post by Scott Gaines
I put bass in the 2 Behringer 12s we currently use, and I can usually hear myself pretty well. And our keyboard player has a pair of K8s that we also use. But the K8s don't have wedge angles, so they're kind of a drag to use.
But we're sharing monitors, and therefore monitor mixes right now, and that's not really where we wanna be.
 
Our QU16 mixer can give each of us a dedicated monitor mix, so is like us all to eventually have our own wedge. $$$

Sent from my HTC_2Q4D100 using Tapatalk


 3 
 on: Today at 10:38:24 am 
Started by Nathan Riddle - Last post by Nathan Riddle
LMR-400 UF (basically what you quoted) Is what we use for the majority of our RF cables..... Well, what we purchase at least for between antennas and receivers/distros. 

We also use LMR-240, usually it is what most of the manufacturers/distributers are sending out now with large RF orders (or RG8). The few extra dB loss per run for the majority of our applications, it doesn't make a considerable difference between the two (<50ft).

However, for longer runs (100's of feet) LMR-400 is the way to go (or bigger, or fibre for 1000's of feet).

But do realize, that with the larger numbers (LMR-400), it is as thick as a 15A AC cable, and not nearly as flexible. You can fit a few hundred feet (probably a thousand+ feet) of coiled RG8 in the same space as 100ft of coiled LMR-400.

Get in the habit of doing path loss calculations over free space and cable. Find out what your receiver needs for signal strength and figure out what cable best suits your needs. If LMR-240 fits the bill, save some money and get that. But if you really need LMR-400, get the LMR-400.

BRad

Thanks for simplifying all this for me and pointing out the specifics!

Coaxial cable losses at the distances we're working with will always be less than than free space path loss.
 
Pick a coax cable, any coax cable (and a frequency): http://www.qsl.net/co8tw/Coax_Calculator.htm. For safe measure, add 2dB to account for worn connector losses.

Now check the path loss at that same frequency (use "0" for transmitter and receiver gain): https://www.pasternack.com/t-calculator-fspl.aspx.

This is why it's just about always better to get the antennas as close to the transmitters as possible.

I played with both; I wasn't sure about the gain at first but once you stated using "0" it worked itself out. Thanks!

Makes a ton of sense now to use coax to get the antenna closer than leaving the antenna further away.

I need to figure out how to calculate the dB loss of couplers, connections, & cable differences [a rule of thumb].

 4 
 on: Today at 10:31:34 am 
Started by Nathan Riddle - Last post by Nathan Riddle
I just wanted to add to this for those that are new to digital wireless systems.  Digital transmitters are sending data (ones and zeros) so there is no dynamic range component to the signal (in standard terms).  The transmitters are always running at full power compared to analog systems.  There is likely much more energy running through your jumper cables and so a much bigger potential for interference.

For this reason you should use higher grade cables (RG8x or LMR-195) when connecting to your distro.  It's also a best practice to NOT neatly lace all the cables together.  A rat's nest will likely work better.

Thanks for this golden nugget :)

I'm a bit OCD when it comes to cable management so my RF rack looks spic'n'span; I'll have to go clutter it up :(

 5 
 on: Today at 10:22:19 am 
Started by Dave Guilford - Last post by David Allred
At the risk of again not answering the OP's question, that's not how optics works.  All else equal, wider beams lose brightness over distance faster than narrower beams.

It did seem counter-intuitive, but the OP wanted info based on the numbers he provided (which he trusts). 

 6 
 on: Today at 10:17:13 am 
Started by Xiang Cao - Last post by Scott Helmke
Still analog?

 7 
 on: Today at 10:02:38 am 
Started by Mike Pyle - Last post by Nathan Riddle
Happened to me this past week as well.

 8 
 on: Today at 09:49:04 am 
Started by Dave Guilford - Last post by TJ (Tom) Cornish
From the numbers, the 8 deg has a lesser lux drop-off rate from one distance metric to the next.  5x reduction , then 4.1x reduction.  Compared to 6.7x, then 4.3x for the 4.7 deg.
The 8 deg also seems to have a less aggressive drop-off progression.
At the risk of again not answering the OP's question, that's not how optics works.  All else equal, wider beams lose brightness over distance faster than narrower beams.  Either one (or both) of the spec sheets is incorrect, or they are using very different definitions of beam and/or field angle from each other, and the 8 fixture is actually narrower than the 4 fixture, at least for where most of the power goes.

Are the lux ratings of the 4.7 all colors + white, or just white firing? 
It is hard to compare brightness of a white light to a light capable of various colors and white.
Indeed.  Almost certainly the brightness spec is with all colors at full, which is going to be a very different color than the white only fixture.  If the white-only fixture is warm white, the multi-color fixture will have to be turned down to match, also skewing the calculations.

The best way forward is a demo.

 9 
 on: Today at 09:41:33 am 
Started by David Allred - Last post by David Allred
Took me a minute, but having seen the game I know that the GA fan section was on the half of the stadium where the camera was.  Proves what we already know.
 https://www.youtube.com/watch?v=8jgPl3fywFs


 10 
 on: Today at 09:23:17 am 
Started by Nathan Riddle - Last post by Nathan Riddle
As an update.

Thanks for the help everyone!

I used the Combine4 and ran 100ft of Generic LMR-400 UltraFlex with the Shure UA8 (554-626MHz) to the stage on a stand so it was ~6ft high (furthest musician was 15ft away). No complaints from Band, worked flawlessly as far as I know :)

https://www.rushcables.com/BNC-Male-to-BNC-Male-400-UF-Coax-p/ars-28-421-003.htm

I am very curious as to the differences between generic and real LMR cable. I wish I had a measurement system like a OTDR for coax.

---

I'm still a bit lost on the calculations involved for dB loss mainly from passive/active splitters and couplers. I get the free space vs cable loss calculators now.

I'll most likely start combining 6x units soon. So I'll need to start figuring out passive/active combining best practices.

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