Mic preamp for classical guitar & other classical instruments

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Aleguitarpro

Well-known member
Joined
Dec 28, 2011
Messages
179
Location
ITALY
Hi.

Tomorrow I'll sell my Focusrite ISA 828.
I've bought it 2 years ago to record classical guitar and acoustic instruments in general but I've never been fully convinced of its sound...
Then, I've built a 4 channel API 312 preamp and I discovered that it works better in acoustic recording.
More attack, depth.

I've bought ISA for its clearness but the results haven't been up to my expectations.

I've built also a G9 and I've 2 TL AUDIO pre.

Someone can give me some advice on a DIY preamp for this purpose?
I want to reproduce exactly what I play.

Thank you very much!
A.
 
Matador is coming out with a new layout for Dan Kennedy's GR2 preamp. I haven't used the Great River yet, but it's supposedly in the same ballpark as the Jensen/Hardy pres, which are a great choice for acoustic instruments. I guess that's one or two levels removed from a solid recommendation--but that's what I would build if I wanted to do classical recordings. The SSL 9K is another less expensive choice.

Dylan
 
SCA J99.  I also think the Lola would be cool to check out for this.

The best pre I have heard for this is the Buzz Audio pre.
http://www.buzzaudio.com/products/ma2.2.htm
 
Okay, forgive me for promoting my own stuff... but the feedback and listening on the new Expat Audio Eden Mic Preamp is that it's "Super Clean" - (Keith SSLTech's words, not mine! and he's VERY hard to please)

When you have a chance, have a look at http://expataudio.myshopify.com/collections/mic-pres/products/eden-microphone-preamplifier

It may fit your application. (granted, it may not too... but I felt you should know what's available in the "Super Clean" Category!  ;D

Good luck with finding your tone.

/Rochey
 
Dylan W said:
Matador is coming out with a new layout for Dan Kennedy's GR2 preamp. I haven't used the Great River yet, but it's supposedly in the same ballpark as the Jensen/Hardy pres, which are a great choice for acoustic instruments. I guess that's one or two levels removed from a solid recommendation--but that's what I would build if I wanted to do classical recordings. The SSL 9K is another less expensive choice.

Dylan

I would think Dan's first preamp would be a little better for this application.  I have used all his pres and his first version is just a little cleaner and sounds great on acoustic sources.  So does his mic pres in the master mix but that isn't DIY.  haha

I would rate them in this order for clean and great sounding on acoustic sources.
1. Buzz
2. GR first pre (I believe this can be DIY'd)
3. SCA j99 (DIY)

I would love to hear your pre Rochey.  Sounds interesting.
 
dandeurloo said:
Dylan W said:
Matador is coming out with a new layout for Dan Kennedy's GR2 preamp. I haven't used the Great River yet, but it's supposedly in the same ballpark as the Jensen/Hardy pres, which are a great choice for acoustic instruments. I guess that's one or two levels removed from a solid recommendation--but that's what I would build if I wanted to do classical recordings. The SSL 9K is another less expensive choice.

Dylan

I would think Dan's first preamp would be a little better for this application.  I have used all his pres and his first version is just a little cleaner and sounds great on acoustic sources.  So does his mic pres in the master mix but that isn't DIY.  haha

I would rate them in this order for clean and great sounding on acoustic sources.
1. Buzz
2. GR first pre (I believe this can be DIY'd)
3. SCA j99 (DIY)

I would love to hear your pre Rochey.  Sounds interesting.

Dan, that's the one I was thinking of--the clean design before his NV series. The layout Matador is working on is compact and looks well done, and also has options for various transformers, etc. Gustav may also be doing a board.

Dylan
 
http://www.johnhardyco.com/JTS9902ChDetails.html

or roll your own. There should be several clone projects around, but I'm not up to date with them. The most important factor contributing to the sound are the transformers. Trust those jensens. It's no accident this particular combo became the "transparent" workhorse.

Or don't roll your own because getting your build quality to this level is a wee bit of a bother.

TSMP3-4.jpg
 
Aleguitarpro said:
Hi.

Tomorrow I'll sell my Focusrite ISA 828.
I've bought it 2 years ago to record classical guitar and acoustic instruments in general but I've never been fully convinced of its sound...
Then, I've built a 4 channel API 312 preamp and I discovered that it works better in acoustic recording.
More attack, depth.

I've bought ISA for its clearness but the results haven't been up to my expectations.

I've built also a G9 and I've 2 TL AUDIO pre.

Someone can give me some advice on a DIY preamp for this purpose?
I want to reproduce exactly what I play.

Thank you very much!
A.

It seems reasonable to use different microphones for different instruments, but mic preamps should be orders of magnitude more linear and accurate.

Of course opinions vary

JR
 
Aleguitarpro said:
... for this purpose?
I want to reproduce exactly what I play.

A.

You probably have this well in hand, but my first curiosity would be:

Mic(s) placement and type (cardiod, omni)
Room arrangement
Microphone(s) used
Preamp

In that order.

Changes in that list have diminishing returns... and the first two are at least an order of magnitude more important.

bb
 
Rochey said:
Okay, forgive me for promoting my own stuff... but the feedback and listening on the new Expat Audio Eden Mic Preamp is that it's "Super Clean" - (Keith SSLTech's words, not mine! and he's VERY hard to please)

/Rochey

I am always interested the specs of mic preamps that are considered clean sounding. I downloaded the user guide which gives the very impressive graphs of measured distortion. I notice that these are measured at an output level of 0dBu but that no load is specified. Can you tell me the load that was used? As I am sure you know, distortion increases with level and applied load. So, I would be interested in its distortion at peak levels, for example at +22dBu into a 600 ohm load.

Cheers

Ian
 
Thanks to all!

I'll try your recommendations.
First pre that I'd like to DIY (due to his low cost) is SSL 9K pre.
Coming from a 5532/5534 pre (FF828) I'd like to listen this project.

I'm very interested in John Hardy pre and in GR.
I don't remember where, but I've read that GR mp1 pre are somethink like a NEVE-sounding pre.
Obiouvsly, different transformer choice affect in a great way the sound of that pre...

bruce0 said:
Aleguitarpro said:
... for this purpose?
I want to reproduce exactly what I play.

A.

You probably have this well in hand, but my first curiosity would be:

Mic(s) placement and type (cardiod, omni)
Room arrangement
Microphone(s) used
Preamp

In that order.

Changes in that list have diminishing returns... and the first two are at least an order of magnitude more important.

bb

I've tried in this years many different placement and mics.
My favourite choice is a 3 mic arrangement: one mic as spot in front of/near the bridge and a stereo couple (AKG 414 ULS matched pair) placed about 1m far from the guitar, in front of the neck joint.

I like very much (but not for classical solo recordings) an M/S placement (AKG 414ULS or an old RODE NT-1 as figure-8 SIDE and another AKG 414/OKTAVA MK-012/neumann KM184 as MID).

I use this placements/mics in my studio (5 x 4m room, with traps, diffusors, etc) and in in-place recordings (churches, theatres, etc).
So, the problems that I noticed are in all these situations.

I've tried these preamps: AVALON 737, FOCUSRITE isa828, TL AUDIO 5051 (worst choice for this applications), my G9 pre, DBX386, API 312 clone.
Probably these aren't the best choice for classical guitar, so I've started this thread.

A.
 
ruffrecords said:
Rochey said:
Okay, forgive me for promoting my own stuff... but the feedback and listening on the new Expat Audio Eden Mic Preamp is that it's "Super Clean" - (Keith SSLTech's words, not mine! and he's VERY hard to please)

/Rochey

I am always interested the specs of mic preamps that are considered clean sounding. I downloaded the user guide which gives the very impressive graphs of measured distortion. I notice that these are measured at an output level of 0dBu but that no load is specified. Can you tell me the load that was used? As I am sure you know, distortion increases with level and applied load. So, I would be interested in its distortion at peak levels, for example at +22dBu into a 600 ohm load.

Cheers

Ian

Ian,

I'm still a relative novice with theAudio Precision. I set input to 0dBu, output to 22dBu, and i'm getting excellent thd+n. 0.008 percent or so on the one unit tested.

However, that is with the default load. I'm not sure how to change the loading to be 600ohm.
(i'm working on that)

The output is driven by a drv135... Designed for 600ohm and high swing.

More data to come, but so far, things look positive!

Cheers

Rochey
 
Aleguitarpro said:
Someone can give me some advice on a DIY preamp for this purpose?
I want to reproduce exactly what I play.
Anything that doesn't have transformer in it.
Perhaps something based on one of the high-quality chips by THAT or TI, or a proven design like a Cohen.
But you may not like it...
 
Now that you've listed them, I would perhaps rethink the choice of mics. Of the ones mentioned AKG 414 and OKTAVA MK-012 should deliver quite transparent results. But these are certainly not "perfect capture" devices. While AKG 414 has a great off-axis response (one of the signatures of a great mic in general) it's still a skewed lens that emphasises high mids, no matter how you place it. Octava depends entirely on the pattern you've screwed in and you mentioned none of that. You can work around these limitations. Do you have an assistant in the studio? Your understanding of mic set up seems stellar, but are you sure you are placing the mics optimally?

If you've considered all of this and things still don't work out, there are certainly some brilliant "perfect capture" mics. But this is where it gets quite expensive.
 
I've put a sample recordings here:
http://soundcloud.com/aleguitarpro/classical-guitar-recording

This was made with 2 AKG414ULS, an old Rode nt1 with DAT recorders but I don't remember the preamps used (from mine... for ex. FF828, DBX. I don't think Avalon).

I don't like the sound in this recording. We made it in a theatre.
Mic position as I described.

Kingston said:
Now that you've listed them, I would perhaps rethink the choice of mics. Of the ones mentioned AKG 414 and OKTAVA MK-012 should deliver quite transparent results. But these are certainly not "perfect capture" devices. While AKG 414 has a great off-axis response (one of the signatures of a great mic in general) it's still a skewed lens that emphasises high mids, no matter how you place it. Octava depends entirely on the pattern you've screwed in and you mentioned none of that. You can work around these limitations. Do you have an assistant in the studio? Your understanding of mic set up seems stellar, but are you sure you are placing the mics optimally?

If you've considered all of this and things still don't work out, there are certainly some brilliant "perfect capture" mics. But this is where it gets quite expensive.

Is very difficult to make a perfect clear classical guitar recording and it's quite simple to obtain a "wolly" sound.
I'm trying to discover the best match with mics/pre/placement.
I've bought these AKG414 ULS for their ultra-linear response and it wasn't simple to find a matched pair of that.
I haven't tried DPA or Earthwork that someone judge the best choice for classical guitar...
And yes, I've an assistant because for me it's quite impossible to place a mic, play, record and listen at the same time!!
Let me know if you judge this recording bad.
It will be a good starting point.
Thanks,
A.
 
Thanks for the example. I would say this recording is not optimal. There is far too much low mid range present (200-500hz), and they obscure the more interesting aspects of the performance (transient information, hand movements). The tone is more like a "piano" and I doubt the guitar sounds like this in the theatre.

Sounds like a mic placement problem first and foremost. You should be able to get much better results from AKG414 and certainly the preamp is decent already, whatever it was. Perhaps the mics were too close, perhaps one of them pointed at some louder body resonance point (something that is hard to catch by ear).

I happened to run this to a high end mastering EQ while I was listening and was able to make a tremendous improvement just by cutting some of that low mid range and boosting high frequencies. This should really be done by changing the mic placement.

But then again, it's not exactly illegal to use EQ after the fact. The information was already there in the recording, just obscured.
 
Kingston said:
Thanks for the example. I would say this recording is not optimal. There is far too much low mid range present (200-500hz), and they obscure the more interesting aspects of the performance (transient information, hand movements). The tone is more like a "piano" and I doubt the guitar sounds like this in the theatre.

Sounds like a mic placement problem first and foremost. You should be able to get much better results from AKG414 and certainly the preamp is decent already, whatever it was. Perhaps the mics were too close, perhaps one of them pointed at some louder body resonance point (something that is hard to catch by ear).

I happened to run this to a high end mastering EQ while I was listening and was able to make a tremendous improvement just by cutting some of that low mid range and boosting high frequencies. This should really be done by changing the mic placement.

But then again, it's not exactly illegal to use EQ after the fact. The information was already there in the recording, just obscured.

Maybe the sound it's a little bit dark because in this recording I used a very old guitar made in 1940 in Barcellona.
It was tuned at 435 instead of 440hz.
Maybe it encrease the effect you descibed, maybe the mic placement wasn't done well.
Now I remember that on that occasion we used DBX386 modded pres.
Thanks for your analysis!
 

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