Thinking about DL32R for church praise team

[WK154]

Ah yes, a sound system designed by committee and politics. I think you may want to get some local qualified outside help on this before cobbling more together. With 200-300 members it cant be much of a budget.
Good Luck

[Kblue]

I think you may want to get some local qualified outside help on this before cobbling more together. With 200-300 members it cant be much of a budget.
Good Luck

Thank You

To replace our old mixer, I think I am OK with qu-24 unless I found something else.
After changing mixer, my next project would be to replace speaker and Amp...
I would need some outside help... My church ceiling is only about 20 ~ 25ft... 

   

[Kblue]

The pre's for example are quite good, no 20 cent op-amps,  a lot more linear and faster with $6 op amps and better matched low noise JFets.

I am a retired engineer (not audio engineer) but very familiar with signal-to-noise ratio stuff...
Just wondering if you know typical noise figure (or noise temp) of those low noise JFETs typically used as 1st stage amp ?
 

[robbocurry]

If you're not stuck for space, for your environment I suggest you buy a mixer with faders and iPad / Android remote control.
Perhaps a little more expensive than the Beh....er x series, but imho with a whole lot friendlier user interface (amongst it's many attributes) is the Allen Heath QU series.
Well worth a look and a pretty solid and safe investment for your church.

[gerenm63]

"However ...

If you have "live" situations, such as a praise band or orchestra, then these systems are not what you want, at least not for the entire system. But, I'll also agree with WK (with whom I often disagree ) that a digital mixer such as a Mackie DL or a Behringer X32/Midas M32 would not be a good choice if your operators are untrained. I've found that it's easier for inexperienced operators to wrap their heads around analog boards -- even complex boards like the big Allen & Heath, Yamaha, and others."


My turn to disagree  . I would not throw hundreds of knobs at the uninitiated (analog). My experience especially in schools and other places is that it's always a challenge for someone to keep their fingers off the knobs. They may be able to get a sound eventually out of the unit but what a sound? I have used the XAP800 in live performances and with great success. The pre's for example are quite good, no 20 cent op-amps,  a lot more linear and faster with $6 op amps and better matched low noise JFets. Try 15 eq's, compressors and delays in addition to the traditional 3. Crossovers etc. Full matrix routing, test signal generator and the list goes on. Setup requires experience, operating very little.

I only made this comment based on the experience of actually doing it. I find that it's far easier for the uninitiated to equate an analog board to something they're familiar with (I tell them it's just like a big stereo setup, which usually puts them at ease pretty quickly). I start with the basics, and add as needed.

I guess it's all in the approach, but I've always found it easier to train people on analog first, then they can pretty easily make the leap to a digital.

[gerenm63]

Ah yes, a sound system designed by committee and politics. I think you may want to get some local qualified outside help on this before cobbling more together. With 200-300 members it cant be much of a budget.
Good Luck

That's why I suggested he talk to Charles....

[gerenm63]

You also forgot the thousands of churches.

I am wondering what mixer they are using for their praise team...

I've seen everything from mid-sized Mackies to huge 64 channel Allen & Heath GL3800s. And some have more than one space, with different systems in each.

[gerenm63]

The reason I said better sound is to give some reference point about what I need to those who suggesting polycom or biamp...
I would have to explain church council why I installed mixer made by a company who builds speech-device like phone and video conf... 

I found compress was very important for live vocal...specially for female singers whose voice becomes so sharp and loud all of sudden at high tone...
And many times, a guest speaker comes too close to condenser mic with loud voice...

Biamp is an audio systems company, first and foremost. Telephony is a relatively recent add for them (and, like audio, they do it quite well).
Polycom is a teleconferencing company first, anything else secondary.

[sam.spoons]

It seems to me that you need two systems here. A system which works well for simple speech and recorded music, un-supervised and another for the praise band. The former is never going to be a satisfactory solution for a live music based service/event, the latter will never be suitable for unsupervised operation. I'd have a small simple analogue desk (A&H Zed 10 or similar) on stage and a digital desk at the mix position. If budget will allow a digital stagebox would give you plenty of I/O for extra monitors. If budget is tight the only game in town is the Behringer X32/S16 setup (an X32 Compact and single S16 costs around €3000 an A&H Qu24 is €3800 with stagebox).

[WK154]

The pre's for example are quite good, no 20 cent op-amps,  a lot more linear and faster with $6 op amps and better matched low noise JFets.

I am a retired engineer (not audio engineer) but very familiar with signal-to-noise ratio stuff...
Just wondering if you know typical noise figure (or noise temp) of those low noise JFETs typically used as 1st stage amp ?

Ultra low noise Jfets and other input transistors are usually classified in this app by 1/f spec in < 1nV/√Hz . I was involved in the late 70's in a far more demanding preamp app for counting electrons. Input transistors at LN temperatures. Here is a current article that covers the various noise sources of the type I'm talking about.
http://www.sciencedirect.com/science/article/pii/S0168900215009766
Granted audio app needs nowhere near this low noise since passive components become the major source of noise and Jfets less of a source. Hence quality low noise resistors, caps etc. play a role in good preamp design. Mackie actually used NPN Epitaxial's 2SA1084 for their first stage in the 1604 series. Onyx pre's varied with different input transistors for different models. A good source for preamp info is That Corp and Jensen transformers. Basic preamp design note from That.

http://www.thatcorp.com/datashts/dn109.pdf

300 ft of cable isn't helping in your case. Check the impedance of each of the twisted pairs and you'll see what I'm talking about. Bill Whitlock covers that nicely in his app notes on CMRR. What Engineering field did you practice?

P.S. If your background noise is in the 60 - 80 dBSPL range none of the above matters since it is lost in the noise (pun intended). Church app is much quieter hopefully.

[Kblue]

What Engineering field did you practice?

Thanks for the info...

I was initially Telecom-backbone Eng... I went through so many technology changes... Spent a lot of time on early-day Internet backbone...
I was sick and tired of man-made logic... So I changed it to RF(active and passive) where more law of physics (God-made logic) plays... 
Still doing some consulting work as spec writer...
Lowest Frequency I ever dealt with is around 950 MHz...generally, 14 - 30 GHz... all modulated digital signal...

This Audio world has been always amazing...100 Hz to 20,000 Hz(whatever highest)...200 times wavelength difference...

I need to read manual A&H Qu 24...
 
 

[Kblue]

300 ft of cable isn't helping in your case. Check the impedance of each of the twisted pairs and you'll see what I'm talking about. Bill Whitlock covers that nicely in his app notes on CMRR. What Engineering field did you practice?

I read it very briefly by skipping some details (It has been so long I ever dealt with Op AMP...) but very interesting fact about balanced circuit.
In shielded twist pair, I seem to understand potential creation of unequal capacitance between two inner conductors in reference to the shield and this will be amplified by Diff Op-Amp... This is very good...

Maybe the problem we are having with keyboard connection is related to ground terminated both end.  I will take a look at it.
I guess I need to isolate GND at DI.

Not familiar with MIC circuitry, but my gut feeling tells me  shield can not be removed at receive side for passive mic and pre interface...
What about active mic like phantom? Is ground pin in XLR used for 48V return?

[WK154]

I pretty much covered the gamut from X-rays to audio. Just haven't got to subsonic, it's hard to keep a whale for a pet.    The impedance mismatch gets past the differential input circuit as noise. You definitely have two totally different ground potentials being 300 ft apart. A DI box is a essential audio tool and if it's noise from the KB the Di box will deal with it. Passive at mixer end is my preference. Yes the shield is the 48V return in the XLR.
Bill Whitlocks app notes AN003,004,006,007,009 pretty well cover all those issues.
http://www.jensen-transformers.com/application-notes/

P.S. most KB are unbalanced outputs and 300 ft. is going to be a problem.

[WK154]

I don't have a good idea of the actual church layout but you said it was a 300 ft straight shot for the cables. That would be a problem for wireless as well at a 100 meters for FOH. Any chance to move closer? Also since you have 15 cables and your typical use is 10 what is the need for a 24 input mixer? Your condenser mic is what brand and model?

[sam.spoons]

As WK says pin 1 (ground) is 48V -ve and pins 2 and 3 carry equal potential (48V +ve) so there is no potential between them (which would damage dynamic mics). I would have thought the DI needs to be at the keyboard so that most of that 300' run is balanced?

I guess the 300' run follows a convoluted path and the mix position is somewhat closer to the stage as the dove flies? 300' from stage to mix position might be alright at Woodstock but indoors...... (and would represent a delay of around ⅓ sec).

If you choose to go digital with faders a digital snake would remove all those issues (though 300' is towards the extreme end of what cat6s can handle in that context). Another option might be a side of stage desk position and cover the FOH mix wirelessly from the floor with an iPad (more than adequate for 10 channels). Whether you go for a desk with faders or a rack mount stagebox style like the DL32R (or Berry X32 Rack) I would still consider the small analogue desk as a backup/un-attended solution.