Topic: SOUND PROFESSIONALS SP-CMC-2 - Do they need a High SPL Mod?

[darktrain]

Just got a pair of these for my cousin(getting him started) and i have read conflicting things on the AT831's(SOUND PROFESSIONALS SP-CMC-2 ), do they need the 4.7k high spl mod like the 853's or not with the single mini jack and powered by a battery box?

[olyrc]

I ran those same mics through a batt box for my first rig and had no problems.

[darktrain]

They will see most of there duty running smaller rock type shows

[nameloc01]

Three wire mics perform best when powered "3 wire". If you already have a battery box (SP) and they are already terminated into a single mini plug, you will run into clipping (at some point) ealier than you should.
"Modding" the mics is definitely cheaper than powering them "3 wire" but the trade off is the performance is not as good.(Spl handling is NOT AS high and the noise/distortion is not lowered in relation to the gain loss) So...decisions..decisions...

[darktrain]

he is getting a 9 or 12v bb with single 1/8 input so looks like i will just do the 4.7k high spl mod for him on it, if he gets into it like me(it may run in our blood) then he won't have them for long it will be a steady spiral downward(in the pocketbook that is) toward better sound

[nameloc01]

Probably best to not jump in head first right off the bat. I am all too familiar with the "downward spiral".
I used to run a pair a 829s with a SP/BB...I actually only had clipping I think 2 or 3 xs'. But, of course, it happened at the shows I wanted to get done well the most. Seems like that's how it always works.
What's he recording with?

[Will_S]

Try running them as they are first.  The 2wire 831s are less prone to distortion than the 853s.

Regarding gain loss, as wired now the 2-wire AT831s (without the 4.7k mod) offer MORE gain than they would if 3-wire powered.  So you'd get the best S/N performance as wired now, if you don't run into distortion problems.

[nameloc01]

I said 3 wire provides higher spl handling, and WITH the mod there is gain loss. I think you misread what I wrote.

[nameloc01]

Also as I was told when you "mod" the mics and lower the gain(sensitivity),the noise/distortion remains the same, it is not lowered in relation to the gain loss. Hence more noise,less gain.

[Will_S]

I said 3 wire provides higher spl handling, and WITH the mod there is gain loss. I think you misread what I wrote.

No, I'm just saying there is MORE gain with the mics how they are right now (2 wire, no mod) than if they were converted to 3 wire or 4.7k mod, which are very close in sensitivity with 3 wire being maybe 2 dB more sensitive than 4.7K mod but both being 10+dB less sensitive than straight 2-wire.  

So in other words, converting the mics from 2 wire (no 4.7K mod) to 3 wire also causes gain loss.  So gain loss is really not an argument in favor of 3 wire power.

[Will_S]

Also as I was told when you "mod" the mics and lower the gain(sensitivity),the noise/distortion remains the same, it is not lowered in relation to the gain loss. Hence more noise,less gain.

Again, 4.7K mod vs 3 wire is only a trivial gain loss, ~2 dB, so the noise floor change is pretty trivial as well.  Especially for earbleedingly loud rock concerts where SPL handling becomes an issue, the noise floor of the mics is moot.

[nameloc01]

Still is not the best way to go. The best way is the best way. The real only issue to modify the mics is its more cost effective. Like I said, he probably is best modding them, as he is new and might decide after pull #1 he hates it. hopefully not.
Not trying to argue, but whenever someone askes about the right way, its my policy to inform them. Same as if someone asked what the best clips for Schoeps mics are,...that would be Schoeps clips. Not to say there aren't other clips that would "work"...same thing.
Again..not trying to argue.

[darktrain]

I am pointing him in the direction of a h320 or ihp120, they are solid little machines and with the rockbox agc its basically hit record and thats it, don't want to muddle his mind with preamps and gain control yet, i will wait till he has the "fever" to delve into that and more, just like when i started off with the giant squids and mz-r70 to the nbox and mk4's(its all such a blur)

[nameloc01]

I hope you fully enjoy watching his complete demise into a full-blown gear slut. lol

[Will_S]

Agree with you (nameloc01) to a point, but...

The real only issue to modify the mics is its more cost effective.

That's simply not true.  Other advantages of modded mics over 3 wire power (especially as provided phantom adapters) are:

1. Smaller package, including the ability to run directly into many recorders without even a battery box.
2. Better battery life (vs adapters, or straight into a recorder vs. with a battery box).
3. Easier compatibility with off-the-shelf mini preamps, which some people choose to use (or are basically required to use for good signal to noise performance on quiet material).

Is that a worthwhile tradeoff against a potential 2dB rise in the noisefloor, that will be inaudible in most circumstances?  Maybe not for some people, definitely so for others.

Darktrain, FWIW, I have run 4.7K modded AT853s directly into an iRiver H120 at moderately loud rock shows with no distortion.  I think the H320 offers similar plug in power, but I don't know how the 831s would fare run straight in with no BB.