[DaveRedRef-III]

Yes but that depends on my non existent playing abilities! But I think I will get one and thanks for the idea. My son is a grade 2 guitarist, and his teacher is very good, so I will be recording them practicing. At the same time it will give a natural voice test too.

One thing I will try is loud fireworks - the initial crack, the LF bloom, and the way the sound reverbs around the valley will be a good test of depth too.

I will be getting wood blocks though - reproducing the timbre of a wood block naturally is quite a challenge, plus you have the initial transient whack which is really difficult to get right. And its something one can play consistently too.

These initial tests will be crucial, so I can optimise the design of the ADC - in terms of the power of the noise shaper, and in how the system decimates from 104 MHz 6 bits back down to 768 kHz 24 bits. In current ADC's this decimation is done very crudely using simple moving average filters.

The microphones I am thinking of using is the Earthworks QT50 using a Schneider disc. This technique has the benefit of recording phase information as well as amplitude differences. Plus using omni-directional mics to my mind is the best way of encoding depth cues - at least that's the advice I have been given. The QT50 is impulse accurate up to 50 kHz too, and is ruler flat from 5 Hz to 50 KHz.

Rob 

You never know you may have hidden talents as a drummer Rob.

Earthworks QT50 sounds a great mic solution looking at its spec, though I have not used one myself.

I like your 'fireworks' idea also.

 

[rkt31]

recording of some natural panning sounds like train or vehicle going past may also be an idea of testing the abilities of Davina, though recording such sounds may be a bit difficult. imho recording and reproducing the female vocals correctly is also a very difficult task . unlike analog tape any anomaly/ distortion in digital chain is quickly evident in case of female vocals.

 

[DaveRedRef-III]

recording of some natural panning sounds like train or vehicle going past may also be an idea of testing the abilities of Davina, though recording such sounds may be a bit difficult. imho recording and reproducing the female vocals correctly is also a very difficult task . unlike analog tape any anomaly/ distortion in digital chain is quickly evident in case of female vocals.

I think 'double tracking' provides a useful example of the limitations found in current ADCs. Even Prism converters sound unnatural in this test. That's why I think Davina could singlehandedly prolong the Red Book protocol, which I am sure we will find is a lot less flawed than people ever imagined.

 

[Light - Man]

recording of some natural panning sounds like train or vehicle going past may also be an idea of testing the abilities of Davina, though recording such sounds may be a bit difficult. imho recording and reproducing the female vocals correctly is also a very difficult task . unlike analog tape any anomaly/ distortion in digital chain is quickly evident in case of female vocals.

Miami train?

 

[DaveRedRef-III]

Had to laugh at an old speaker review I just converted from a Norwegian reviewer.

He said it has the warm musicality of a couple of big Sonus Fabers, the speed and detail of an electrostatic and the kick-arse bass of a Wilson Audio speaker. .....He decided to see how loud it would go. .... the snare almost gave me bleeding gums and the church organ bass "did something strange with my ability to breath"

lol

He later complained about getting sea-sick from the organ bass.

 

[Sunya]

 
The microphones I am thinking of using is the Earthworks QT50 using a Schneider disc. This technique has the benefit of recording phase information as well as amplitude differences. Plus using omni-directional mics to my mind is the best way of encoding depth cues - at least that's the advice I have been given. The QT50 is impulse accurate up to 50 kHz too, and is ruler flat from 5 Hz to 50 KHz.

 
Maybe try the Sanken CO-100K with 100kHz bandwidth.
 
https://www.sanken-mic.com:6015/en/product/product.cfm/3.1000400
 
You should register at Gearslutz to get input from recording engineers.
 
https://www.gearslutz.com/board/

 

[isquirrel]

 
Hope everything is okay, thank you for your contributions they have been the mainstay of this forum. I personally owe you a debt of gratitude for all of the painstaking research you have done. I for one have benefitted from it. 
 
Thank you my friend.

 

[Christer]

   
Maybe try the Sanken CO-100K with 100kHz bandwidth.
 
https://www.sanken-mic.com:6015/en/product/product.cfm/3.1000400
 
You should register at Gearslutz to get input from recording engineers.
 
https://www.gearslutz.com/board/

I was going to suggest something similar. Telarc and some  other classical labels use Sanken and DPA and Sennheiser and Thuresson and Bruel and Kjaer and a host of other classic pro mics.
Maybe the QT 50  is a very good mic? But I have never seen it used at any classical sessions.
And at least as far as I am concerned,I couldn´t care less how any mic or ADC captures the already high distortion from an  electric guitar or any other synthetic electronic instrument. The only thing that matters to me is how well any HIFI  or  Pro Audio product, can reproduce the human voice and unamplified acoustic instruments singing/playing in a real venue.
And although there is more compromise. And more  shortcuts  are taken these days recording acoustic music than earlier in spite of at least  theoretically better equipment than in the analogue age,final results are not always better.   
 But Sanken has got a very good reputation among some engineers for being noisefree and with probably the highest bandwidth of any pro mic.
And although I personally can´t identify anything over 19khz as a tone, I suspect that bandwidth matters.
If I was aiming to build a the best possible ADC I would get advice from the engineers working with classical music: Not the pop/electronica , acoustically"dead as a dodo" Pop and Rock studio  crowd, who seem to  care  not at all about realistic sound and acoustics and dynamics.
No wonder most of  what they produce,sounds so terrible when there is no real acoustic captured, most instruments are amplified and musicians with  mics up their nose, at best hear the others  in the studio only via headphones and the dynamic range is only loud,louder and really damagingly loud.
An experienced engineer in the classical genre once told me at  sessions that to capture for example, a violin or cello with their harmonics intact you shouldn´t put your mics closer than 6-8 metres away from them.

 

[Rob Watts]

The problem with the DPA and Sanken is that there is very significant lift at 20 kHz - and I would prefer ruler flat at 20 k and "only" 50 kHz response. I have checked out gearslutz, and the earthworks has been used for classical to good effect. But to be honest, once I get to the point of testing with proper classical music, the real pro engineers we have lined up will take over.
 
Rob

 

[ddanois]

Quick question regarding the volume setting on Dave while using an external headphone amp connected via XLR interconnect...
 
Is there a recommended volume setting for the Dave when using it with a headphone amp (430HA)? Currently, my Dave is set at -15dB while the 430HA is set at 50.0 on high gain and the sound seems balanced but I was wondering if the Dave is supposed to be turned up more to be optimal.
 
Thanks,
Derek 

 

[Sunya]

  The problem with the DPA and Sanken is that there is very significant lift at 20 kHz - and I would prefer ruler flat at 20 k and "only" 50 kHz response. I have checked out gearslutz, and the earthworks has been used for classical to good effect. But to be honest, once I get to the point of testing with proper classical music, the real pro engineers we have lined up will take over.
 
Rob

 
I believe the raised sensitivity of the Sanken over 20kHz is intentional to compensate for the low amplitude of very high frequencies.

 

[Sunya]

  Quick question regarding the volume setting on Dave while using an external headphone amp connected via XLR interconnect...
 
Is there a recommended volume setting for the Dave when using it with a headphone amp (430HA)? Currently, my Dave is set at -15dB while the 430HA is set at 50.0 on high gain and the sound seems balanced but I was wondering if the Dave is supposed to be turned up more to be optimal.
 
Thanks,
Derek 

 
DAVE in DAC mode is set at -3dB; so I'd try it in DAC mode and the 430HA on low gain.

 

[ddanois]

   
DAVE in DAC mode is set at -3dB; so I'd try it in DAC mode and the 430HA on low gain.

Perfect! Thanks for the advice.

 

[Rob Watts]

 

  The problem with the DPA and Sanken is that there is very significant lift at 20 kHz - and I would prefer ruler flat at 20 k and "only" 50 kHz response. I have checked out gearslutz, and the earthworks has been used for classical to good effect. But to be honest, once I get to the point of testing with proper classical music, the real pro engineers we have lined up will take over.
 
Rob

 
I believe the raised sensitivity of the Sanken over 20kHz is intentional to compensate for the low amplitude of very high frequencies.

Yes and that's the problem - one of the depth cues is frequency content, so the brain takes account of the air's HF loss - thus bright sounds sounds closer, and sounds that are distant and so have more HF absorption and so more depth. A bright sounding mic will not help and will foreshorten depth perception. Note I do not want to do any EQ with this project, it has to be as simple and direct as possible.
 
Additionally, the polar response is crucial too - with the QT50 its within 5 dB all angles, so reflected energy won't have a large response variation. Actually the 50 in FR response is amazingly flat from 4 hz to 40 kHz only -1dB down. The impulse response is also superb.
 
But thanks for your suggestion, I had not heard of Sanken.
 
Rob

 

[DaveRedRef-III]

Have just been listening to Sinatra on his Platinum Collection CD compilation. The very last song on the third CD is a 2003 remaster of 'One For My Baby'. There is a wonderful distant recording of the piano in the far right of the recording hall. It shows off the depth capabilities of DAVE quite well I think. What I Was surprised by though is the vocal because it sounds modern in the frequency band and high resolution warmth and clarity. It is so good I thought it must be at least a 70's recording but upon checking it was recorded 25th June 1958. I think this vocal recording is almost up there with Buddy Holly's 'True Love Ways' and worth a listen if any Sinatra lovers do not already have it in their collection. A wonderful, intimate vocal recording with distant piano, occasional close recorded Alto Sax and soft strings

Just thought I would mention it for those interested