Topic: What's wrong with my new SP gear?? (sample included)

[livingdna]

Did a test of my new mics+bat box when Nouvelle Vague visited Aarhus. Sadly the result was far from ideal:
http://www.2shared.com/audio/Y9iTkNyY/NVsample.html

Used following linage: SP-CMC-8 --> SPSB-11 --> iRiver H140 (with Safety option under automatic gain control - however this wasn't activated as I had set the gain sufficiently low (16 dB)).

Can anyone point me in the right direction as to what went wrong? Preferable before Friday when I hope to be able to do a better recording

[acidjack]

That is clearly overloading, but the question is from where.

If you were not running line-in, that is probably the cause.  You should always run mics>BB>line-in unless you cannot get enough gain.   I would also never activate that gain control feature as those are far from precise and not designed for music recording. 

If you were running line-in, that sounds like the mic overloading to me.  Do you have the "low sensitivity mod"?  If you do not, you probably need to send the mics back and have it done.  If you don't have that done, and you're already going line-in, and you're recording loud bands, you're going to be out of luck.

[mr qpl]

try changing the battery, could be dead

[livingdna]

Thanks for input.
I did use line-in and battery is fully charged.

SP recommended me not to go for the low sensitivity option, since I would be recording both loud and quiet gigs. Would I be better off with adding the low sensitivity option?

Another thing I just realized. I forgot to adjust the roll-off switches in the battery box. Thus all switches were closed except for no. 1. I can't find info about what this does but it's not the no-roll-off (16 Hz) option. Could this be the explanation of the overload?

[acidjack]

Bass rolloff has nothing to do with distortion.  SP gave you bad advice.  You need the low sensitivity mod to record loud sources, period.

I would not recommend using the bass rolloff on that box at all.  It can have unpredictable results, and it's easier to do it in post where you can compare/contrast different levels of rolloff.  Those were more useful back in the DAT/MD days when it was hard to do post-processing.

[kfrinkle]

I tried the low sensitivity options with the SP mics, going into a SP battery box (9v) into MicroTrack 24/96.  I never ever ever got good results (distortion always in loud environments, regardless of the levels going into the MT).  I even had the three-wire mod done to them.  It always agitated me that some people running a Sony TCD-D8 with the same set-up otherwise would get decent results.  I quit, got some Church Audio mics + preamp and a Sony PCM-M10 and could not be happier (well ok, I would like some MBHOs, but thats being picky).  Dump the SP mics, get some Church Audios instead, or spend a serious amount of money on the higher end mics.  After yeards of tweaking with my SP mics, I gave up on them, don't learn the lesson the hard way.

[mattmiller]

I used the CMC-8s for YEARS (2002-2009) with their SPSB-1 battery box and never had any problems with them being overloaded until one time in 2009 when a very bass-heavy room gave me some distortion in the low end.  In response, I had them modded to mini-XLR to use the AT phantom power supplies.  That upgrade cost as much as the CMC-8s did in 2002 (the mod was free with the purchase of the two power supplies at more than $100 each).  A few months later, I made the jump to some Neumann KM140s, so I haven't used the CMC-8s much in the last year and a half.  I tape exclusively loud rock shows, although I can't say for sure how loud my shows were in comparison to the ones you're taping.  In short, I wouldn't give up on the CMC-8s.  I'd call or e-mail Chris at SP and see what he thinks.  He'd probably even be willing to listen to your sample to try to diagnose the problem.

[acidjack]

I tried the low sensitivity options with the SP mics, going into a SP battery box (9v) into MicroTrack 24/96.  I never ever ever got good results (distortion always in loud environments, regardless of the levels going into the MT).  I even had the three-wire mod done to them.  It always agitated me that some people running a Sony TCD-D8 with the same set-up otherwise would get decent results.  I quit, got some Church Audio mics + preamp and a Sony PCM-M10 and could not be happier (well ok, I would like some MBHOs, but thats being picky).  Dump the SP mics, get some Church Audios instead, or spend a serious amount of money on the higher end mics.  After yeards of tweaking with my SP mics, I gave up on them, don't learn the lesson the hard way.

Are you referring to the "CMC-8" aka AT 933?  I never had any problem with those, or with the adapter and U853 caps I was using with them. But mine had the low sensitivity mod.  Church are fine mics, but I don't think it's necessary for the OP to spend another $200 on mics when all that he probably needs is a $20 mod that SP should have told him to get in the first place, as far as I can tell.

[fmaderjr]

Another thing I just realized. I forgot to adjust the roll-off switches in the battery box. Thus all switches were closed except for no. 1. I can't find info about what this does but it's not the no-roll-off (16 Hz) option. Could this be the explanation of the overload?

On my 10 year old SP battery box there is no setting at which only switch 1 is supposed to be open. It's possible that that is the problem. For minimum roll off, switches 2, 3, & 4 should be open. The recording doesn't really look or sound like a brick walled recording to me and the show does not sound particularly loud. It sounds fairly decent to me except maybe for the bass.

However even if I am correct, as acidjack says, when recording loud stuff you will run into trouble without the low sensitivity mod even with correct settings on the battery box.

[SmokinJoe]

CMC-8's aka AT933 family are designed by AT to be used in a "3 wire mode".  I mean... that's the way AT builds them... 2 wires for signal plus 1 for ground.  SP and others connect 2 of the 3 wires together, making them into 2 wire mics, because that way they can make a stereo pair which uses a standards TRS minijack (shared ground between the 2 mics).  But then they overload on loud conditions.  There is a "low sensitivity mod" which Chris Church created, more for AT853's than 933's, and SP adopted it.  Chris has said he doesn't think the 900 series benefit, although others have debated that in multiple threads.  Another approach is to use a 3 wire battery box which goes back to using the mics as they were intended.  Then you use either mini-xlr's on the ends of the mics, or separate TRS connectors on each mic, into a battery box that's made for the purpose.  If you decide to go that route, I'd suggest you get the battery box and reconnection done by the same person, because there is no absolute wiring standard on some of that stuff.

While most recorders wouldn't want to use AGC, if you are using a Rockboxed iRiver, using the AGC in "safety" mode is fine.  I always do.  What it allows you to do is set the gain up a bit, and it will "ratchet down" a bit as required.  If the incoming signal is so hot that it ratchets down below 0 you are in trouble, because once you go much below zero that means you are overloading the input to the iRiver, and distortion will be the result regardless of the meters looking fine.

[George]

I've had the mini xlr/3 wire mod from SP for my at853's for years, even before I heard of Church Audio.  I've never had any distortion with mine.

[livingdna]

Talked with Chris from SP, but so far we haven't been able to identify the problem. I am leaning towards it's the lack of low sensitivity option, but I will also be surprised if that's the case since the music really wasn't that loud..

Tonite I will do a recording with my old SP mics and the new battery box to eliminate that the problem is with the box.


On a side note: What would be the better gain control setting to use? Am using iRiver H140 with rockbox, which is offering options such as Safety, Live etc.
Or would I be better of not using automatic gain control and if so what would be a good level for the gain level?

[Church-Audio]

Talked with Chris from SP, but so far we haven't been able to identify the problem. I am leaning towards it's the lack of low sensitivity option, but I will also be surprised if that's the case since the music really wasn't that loud..

Tonite I will do a recording with my old SP mics and the new battery box to eliminate that the problem is with the box.


On a side note: What would be the better gain control setting to use? Am using iRiver H140 with rockbox, which is offering options such as Safety, Live etc.
Or would I be better of not using automatic gain control and if so what would be a good level for the gain level?

I am not trying to sell you something well.. maybe but actually the best option for you is my 9200 or 9100 preamp with my 4.7k mod in it. It allows you to run the mics high sens or low sens and switch between the two so that you can have the best of both worlds.
You might find one on the garage sale section here or you can get one from me. The problem with these mics is they do overload at way less sound pressure when wired in 2 wire mode. Around 10 to 15% thd @ 114 db @ 1k from my measurements.
Chris

[livingdna]

A little update:

I did 2 further recordings to test my new equipment. On both recordings I used the new SB11 battery box, with a pair of BMC-6. One recording was flawless. The other had slight overloading, but nothing compared to the previous recording with CMC-8. The overloading can most likely be ascribed to the extremely loud sound level (the band was Swans). This leads me to believe that acidjack is spot on with the lack of "low sensitivity option" being the cause.

I am not trying to sell you something well.. maybe but actually the best option for you is my 9200 or 9100 preamp with my 4.7k mod in it. It allows you to run the mics high sens or low sens and switch between the two so that you can have the best of both worlds.
You might find one on the garage sale section here or you can get one from me. The problem with these mics is they do overload at way less sound pressure when wired in 2 wire mode. Around 10 to 15% thd @ 114 db @ 1k from my measurements.
Chris

So if the problem really is the lack of low sensitivity option, your preamp could solve it? Or would I still need to have low sensitivity option installed? Would I have to use your preamp instead of the SP batbox? What's the dimensions of your preamp? I really like the tiny dimensions of the SP batbox.

[Church-Audio]

A little update:

I did 2 further recordings to test my new equipment. On both recordings I used the new SB11 battery box, with a pair of BMC-6. One recording was flawless. The other had slight overloading, but nothing compared to the previous recording with CMC-8. The overloading can most likely be ascribed to the extremely loud sound level (the band was Swans). This leads me to believe that acidjack is spot on with the lack of "low sensitivity option" being the cause.

I am not trying to sell you something well.. maybe but actually the best option for you is my 9200 or 9100 preamp with my 4.7k mod in it. It allows you to run the mics high sens or low sens and switch between the two so that you can have the best of both worlds.
You might find one on the garage sale section here or you can get one from me. The problem with these mics is they do overload at way less sound pressure when wired in 2 wire mode. Around 10 to 15% thd @ 114 db @ 1k from my measurements.
Chris

So if the problem really is the lack of low sensitivity option, your preamp could solve it? Or would I still need to have low sensitivity option installed? Would I have to use your preamp instead of the SP batbox? What's the dimensions of your preamp? I really like the tiny dimensions of the SP batbox.

The advantage of my preamp is that you can have the mics wired 3 wire and use my 4.7k mod inside the preamp that can be switched on and off. Allowing you to get the high sensitivity when you need it and low sensitivity when you need it + 20 Db of very quiet gain. Allowing you to tape all kinds of shows quiet and loud with one pair of mics and one preamp. The preamp is 2.5 x 3 x 1 inch