Mics straight to ADC - no preamp

[tenor39]

Very nice sound. Are the C617's that hot? How many mV/p do they output? I've only been able to do this with a DPA 4041, which doesn't even need a preamp with 100mV/p of output.

[MichaelPatrick]

Originally Posted by tenor39

Very nice sound. Are the C617's that hot? How many mV/p do they output? I've only been able to do this with a DPA 4041, which doesn't even need a preamp with 100mV/p of output.

66 mV/Pa (-24 dB ref 1V/Pa)

I have to admit cheating a little as the Benchmark ADC has some line-level gain. I boosted by about 20dB.

I thought this worth posting because it's an interesting setup that I've never tried before. It also helps that the music is beautiful.

[king2070lplaya]

Isn't there an impedance mismatch between the low imp. Mic and the high imp. Line input?

[MichaelPatrick]

Originally Posted by king2070lplaya

Isn't there an impedance mismatch between the low imp. Mic and the high imp. Line input?

It's quite common to terminate lower impedance sources into a high impedance input. A principle of modern balanced circuit design is to let source devices operate without loading, drawing little current from them.

[rumleymusic]

The bass on those 617's always give me goosebumps. I love it.

I remember not having to use very much gain at all on these mics, about 20db sounds about right. The spheres seem to add a perfect amount of high frequency boost.

[shosty]

Originally Posted by MichaelPatrick

Here's a lovely piece by Ennio Morricone from his The Mission movie soundtrack I just recorded in live concert with a pair of Josephson C617Set mics with 40mm spherical baffles on a Schneider disc.

Mics went straight into a Benchmark ADC1; there was no mic preamp. Phantom power was supplied by a Denecke PS-2.

No reverb was added - the sound is 100% natural. MP3 reduces the weight of the organ's low end, but the rest survives well enough.

I love it. Excuse my ignorance but what would be the difference between adding gain on the ADC and using a mic pre? Is the advantage a purer signal due to less electronics?

[MichaelPatrick]

Originally Posted by shosty

I love it. Excuse my ignorance but what would be the difference between adding gain on the ADC and using a mic pre?

Good question. There may be little difference.

Having said that, I imagine fewer devices might help make the sound truer to the original. It's nice to hear good microphones like these with little coloration.

[shosty]

Originally Posted by MichaelPatrick

Good question. There may be little difference.

Having said that, I imagine fewer devices might help make the sound truer to the original. It's nice to hear good microphones like these with little coloration.

Makes sense. Whatever the reason, the poof is in the pudding. It sounds great.

[Mats H]

Originally Posted by MichaelPatrick

Here's a lovely piece by Ennio Morricone from his The Mission movie soundtrack that I just recorded in live concert with a pair of Josephson C617Set mics with 40mm spherical baffles on a Schneider disc.

Mics went straight into a Benchmark ADC1; there was no mic preamp. Phantom power was supplied by a Denecke PS-2.

No reverb added - the sound is 100% natural. MP3 reduces the organ's low end, but the rest survives well enough.

Very clear and smooth sound. Love the evenness of this recording (listening on monitoring that goes to 15 Hz).

Just a question about the impressive output level of those mics: Do you find it a problem with louder source material? Some of my mics must be padded down pretty heavily at times to not distort the input stage of some preamps (KM140 on loud guitar amp come to mind).

[MichaelPatrick]

Mats,

The high output hasn't been a problem with loud material as long as the mic preamp has minimum gain of 3dB to 6dB or so. Preamps that start above that are a problem when SPLs are high.

There's a WAV CD audio version here for those who want to hear the organ lows more clearly.

[Sounds Great]

Originally Posted by MichaelPatrick

There's a WAV CD audio version here for those who want to hear the organ lows more clearly.

Listening on my M50's. That is really beautiful. What a wonderful room, the recording sounds like you're there!

[boojum]

MP - Just lovely. Good room, good mics in the right place and good instrument well played. The sound is grand.

[jacktadoussac]

This could explain why my Josephson C700A sounds pretty darn good with a non-specialist type of mic preamp -- whatever Sound Devices packs into a USBPre 2.

I believe the 617 and C700 share identical innards, in terms of the internal mic amp that fits into the mic body (but I could be wrong).

[Audiop]

Originally Posted by MichaelPatrick

It's quite common to terminate lower impedance sources into a high impedance input. A principle of modern balanced circuit design is to let source devices operate without loading, drawing little current from them.

Yes, and that goes for analog unbalanced signal transmission as well.


/Peter

[didier.brest]

Originally Posted by MichaelPatrick

MP3 reduces the organ's low end, but the rest survives well enough.

Very nice recording !
I could not hear any LF loss in the mp3 and would not commit in distinguishing the wav and the mp3 320 in blind test. Spectral analysis confirmed that the LF end is not affected by mp3 compression.

[MichaelPatrick]

Originally Posted by didier.brest

Very nice recording !
I could not hear any LF loss in the mp3 and would not commit in distinguishing the wav and the mp3 320 in blind test. Spectral analysis confirmed that the LF end is not affected by mp3 compression.

Didier,

That's good to hear because I flatly distrust MP3 to maintain spectral balance and phase. Images get blurred in the sound stage and LFs are sacrificed but, in this case, the kind of music played seems to make it of little effect in the end.