Topic: Preamp or no preamp question

[tbugsett]

I have a new rig which I haven't had much chance to play with yet and now I have an important show coming up very soon.  So I have a question:

My rig is SP-CMC-8>2x AT8532 power modules>R-09  The AT8532 and R09 are connected with this cable:
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-XLRF-MINI-2

And recently I bought a SP-Preamp here at the yardsale, mainly for quiet taping occations. I was just wondering if I have anything to gain sonically by using the preamp for loud rock shows as well? Or is it unneccessary to drag around this extra piece of gear given that I'll have no problem getting good levels without it.  Or in other words: Is the SP-Preamp significally better sounding than the internal R-09 preamp?

My upcoming show will be stealth taping but I assume the security will be pretty lax. So I don't think it will be a problem getting the gear in.  But even so if there's nothing sonically to gain I see no point in going CMC-8>2x AT8532>Sp-Preamp>R-09.  Lots of stuff to drag around but if the sound will be better I'll do it 

And one other thing: Skipping the AT8532 and going CMC-8>Sp-Preamp>R-09 is not an option as the mics terminate in mini xlr's while the preamp has standard 1.8" i/o.

Any suggestions/advices?

Thanks.

[stevetoney]

The biggest issue is making sure your mics don't overload, which is addressed by the phantom power provided by the battery box.  The next biggest issue is making sure you get the cleanest data steam to record, which is addressed by the preamp.

Generally, the preamp will help rather than hurt.  While I'm not an experienced techie...consider this.  All of the top rigs run phantom power to the mics (which is what your battery box does) and then boosts the signal with a high quality preamp.  The reason they use an external preamp to boost the signal is because they are higher quality and lower noise than what is typically included in your normal recording device.

So, if you want, you can run a test of your own.  I recommend performing some tests at home with your home stereo.  Yes, your stereo cannot simulate the live club environment, but it might be able to replicate the sound pressure levels (SPL) your rig will see in the club and that's the biggest thing that you want to test. 

Anyway, I think you'll discover that you're be better off running the battery box AND the preamp in the steam together.

BTW...while it might seem like the best use of battery boxes and preamps is to boost the signal to make acoustic shows sound louder, the REAL benefit of higher power to the mics is to allow them not to overload at high SPLs.  It took me a long time to understand this concept and frankly, I still don't really understand it.  So, in reality you need external power LESS for acoustic shows than you need for high SPL shows.

[SmokinJoe]

I guess I would agree with the previous statement.  I don't have an absolute answer for you, but just let me throw out another data point.

I have SP-SPSM-6 mics which is more-or-less similar to your CMC-8s.  I run them -> SP-R09-POWER -> R09 line in, and it sounds very clean. I think the R-09 internal preamp is OK, but it's not as good as the external preamp. The SP-R09-POWER http://www.soundprofessionals.com/cgi-bin/gold/item/SP-R09-POWER is probably similar to your PRE, except it has no adjustments and it's more compact.  I have run my mics directly into the mic input, and it sounds good, but on quiet situations where you have to crank up the gain, there is a little more hiss.  My guess is that if you have to run the gain on the R-09 almost maxed out, then it's time for the preamp.  In my case, the preamp adds almost no bulk, so I use it virtually 100% of the time.

My 2 cents worth.

[BayTaynt3d]

Just for the record, a battery box doesn't supply "phantom power". Phantom is 48v (soemtimes 15 I think too), the bbox gives you 9v, which is still way better than the R9 will provide by itself.

Second, if the show is loud, then you definitely will want to power your mics with at least a bbox and not with just what the R9 provides. Otherwise you're mic may brick wall like mentioned above. Your little preamp is also probably a battery box too, so it will provide more power to your mics which will help them not overload even if you don't need any gain from the preamp.

So, if you're using those mics at a "loud" show, you should power the mics with a bbox for sure in my opinion. If your little preamp is the only thing that you have to power the mics with, then I'd personally use it, otherwise you are seriously at risk of distortion. And again, this has absolutely nothing to do with gain, that's a whole other conversation in and of itself.

[SmokinJoe]

I think in his case the 9V comes from the AT power supplies, so the 9V from the preamp is redundant, and it's just a boost issue at that point.

I my case, the 9V from the battery box/preamp definitely helps.

[Brennan]

Bay, just wondering..by "brick wall" you mean just a relatively solid wall of distortion over powering the rest of the recording, right?

[Church-Audio]

I have a new rig which I haven't had much chance to play with yet and now I have an important show coming up very soon.  So I have a question:

My rig is SP-CMC-8>2x AT8532 power modules>R-09  The AT8532 and R09 are connected with this cable:
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-XLRF-MINI-2

And recently I bought a SP-Preamp here at the yardsale, mainly for quiet taping occations. I was just wondering if I have anything to gain sonically by using the preamp for loud rock shows as well? Or is it unneccessary to drag around this extra piece of gear given that I'll have no problem getting good levels without it.  Or in other words: Is the SP-Preamp significally better sounding than the internal R-09 preamp?

My upcoming show will be stealth taping but I assume the security will be pretty lax. So I don't think it will be a problem getting the gear in.  But even so if there's nothing sonically to gain I see no point in going CMC-8>2x AT8532>Sp-Preamp>R-09.  Lots of stuff to drag around but if the sound will be better I'll do it 

And one other thing: Skipping the AT8532 and going CMC-8>Sp-Preamp>R-09 is not an option as the mics terminate in mini xlr's while the preamp has standard 1.8" i/o.

Any suggestions/advices?

Thanks.

If you have a battery box with these mics you dont need a preamp for a loud show.. The biggest problem is that these mics overload pretty easy if they are not modified.... I would in the future think about doing the mod that I do to your mics its pretty easy to do if you can solder you can do it your self. You simply convert the mics to two wire.. use the red wire in the cable for the signal output and the Yellow wire gets connected to one half of a 4.7k 1% resistor the other half of that resistor gets connected to ground.

Then you dont need your power modules you can simply use your edirol by it self and just the mics for loud shows and let the edirol power the mics. Or for more quiet shows you can use your SP preamp and edirol with your mics. There is a real misconception that increasing the voltage to these little mics decreases distortion.. I have measured the difference between 5 volts of mic power and 10 volts, the difference in distortion is .05% not much to write home about. So I think your better off converting your mics. IMO that gives you the most stealthy option.

[tbugsett]

Thanks for all the comments and suggestions.  Much appreciated!  Just to clarify regarding the powering/battery box issue: The AT8532 power modules which I have are supposed to be different to the SP (or others) battery boxes.  I have two AT8532, one for each mic. And each run on a 9V battery.  As per soundprofessionals they're supposed to handle SPL better than the battery box: Max input without distortion is 138dB as opposed to the battery box max 125dB. That's why I choosed the AT8532's instead of a battery box.

Quote from Soundprofessionals:
 "For intensely loud situations, consistent with highly amplified concerts at close distances to the speakers, you can add a set of Ultra high SPL power modules (AT8533 or AT8532) with locking connectors between the mics and the power modules. In this configuration, the mics remain balanced.(..) With the AT8532, the microphones will run on each modules standard 9v battery or 9-52v phantom power. This configuration provides the highest level of SPL capability. The output of the modules are XLRM plugs."

[Church-Audio]

Thanks for all the comments and suggestions.  Much appreciated!  Just to clarify regarding the powering/battery box issue: The AT8532 power modules which I have are supposed to be different to the SP (or others) battery boxes.  I have two AT8532, one for each mic. And each run on a 9V battery.  As per soundprofessionals they're supposed to handle SPL better than the battery box: Max input without distortion is 138dB as opposed to the battery box max 125dB. That's why I choosed the AT8532's instead of a battery box.

Quote from Soundprofessionals:
 "For intensely loud situations, consistent with highly amplified concerts at close distances to the speakers, you can add a set of Ultra high SPL power modules (AT8533 or AT8532) with locking connectors between the mics and the power modules. In this configuration, the mics remain balanced.(..) With the AT8532, the microphones will run on each modules standard 9v battery or 9-52v phantom power. This configuration provides the highest level of SPL capability. The output of the modules are XLRM plugs."

I have measured the AT 853 mics they had a distortion of 1.5% at 114db at 1k I think that SP has quoted the specs of AT but IMO the specs are wrong. After my simple mod the distortion is 0.5% at 114db at 1k.

I wanted to clarify I am not saying SP is misleading people! they are simply stating the specs that Audio Technica provided. I have found for what ever reason that the distortion specs for the 853 are not correct. This was from my own tests. And the simple fact is if the max distortion level really was 138db NO one would ever have a problem with mic overload. But we know thats not the case they do distort. I am not saying they are a bad microphone I love the sound of the 853 I think its a great mic.. But if you do my simple mod to them they dont have the distortion problem anymore.

[SmokinJoe]

Actually, I think the CMC-8 has something other than AT-853.  It has ES943, which it appears is one step up from that 853, or at least that is what marketing would have you believe.  Anyway, the spec is probably a little different.  I thought about getting a set of these... the little samples they have on the website of Van Morrison and James Taylor sound really nice, and those are without preamps.  Yeah, I should have gotten a set of these.

[Ryan Sims]

Hey Thor.

I agree with everyone here that it would be beneficial to use the pre.  I also wanted to give you another +T in hopes that it treats you well and to thank you for such a great smooth transaction on this very box!

All the best,
Ryan