Discussion in 'Microphones (live or studio)' started by aracu, Nov 22, 2006.

  1. aracu

    aracu Active Member

    Sep 27, 2005
    This is a miniature composition made by blending short
    recordings of prepared santur together. The mics used
    were an AKG426 set to fig 8's through GordonV pres
    and a pair of Senn800's set to omnis or fig 8's, through
    Sound Devices 744t pres. Sometimes the 800's through
    the 744t pres sounded better on their own.
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  2. mdemeyer

    mdemeyer Active Member

    Dec 22, 2004
    Dublin, CA USA

    Interesting composition, but I have to confess that it's not my cup of tea.

    I do have two questions for you...

    You mention using the 744T with the MKH800s. I recently got a 744T to use for my concert recordings to reduce the hassle of using a notebook. I'm planning to use my primary mic pre (Hardy M1 x 4) into a Benchmark AD2404-96, then dual AES/EBU to the 744T.

    I did some comparisons (measurements at this point) of the A/D and mic pre in the 744T and found something interesting in the mic pre that maybe you can comment on. The noise floor of the mic pre (although not the A/D through the line inputs) has a really high noise level at low frequencies, while being very quiet in the upper frequencies. Here are two plots showing the noise floor of the M1 (red) vs. 744T (blue). Both were terminated with a 150 ohm MF resistor, and the M1 was run into the 744T line inputs with the gain set to zero.

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    You can see in the two plots taken at 40db and 60db gain (I usually operate in this range), that the 744T has a rapidly rising noise floor with decreasing frequency. The Hardy is actually slightly noisier from 800Hz up (at 40db gain) and quiet a bit at 60db gain above 100Hz. So I'm expecting the 744T to sound quieter given the ear's sensitivity to noise vs. frequency.

    I send these plots to Sound Devices, and they confirmed that this is the designed performance. They didn't say it specifically, but I asked if this was a form of 'noise shaping' to improve the weighted (and audible) noise level, and their response did not suggest otherwise.

    I'm just wondering if you have found this to ever be a problem, or perhaps if you run the unit with the HP filters engaged. Really wish there was a 20Hz setting on those --- the lowest now is 40Hz.

    I'm also wondering how you (or others) feel about the MKH800? I have always eyed that as a very versatile mic for acoustic concert recording (instrumental and choral mostly), but the generally lackluster comments about the MKH series in general (thinking about the 20/40/etc.) have held me back from the MKH800. You seem to feel it has some synergy with the 744T, it seems.

    Thanks for posting the sample, and keep up the creative work.

  3. aracu

    aracu Active Member

    Sep 27, 2005
    I have not had any problem with noise being audibly produced
    with the 744t pres, but I've been using those pres usually
    with the Senn800's which have a very high output level, and
    occasionally with the AKG426, which has a fairly high output level.
    I have not tried using those pres with a dynamic or ribbon mic,
    which would put them through a more realistic test. Tested a friend's
    new tube mic through them (don't remember the name offhand)
    and there definately was a noise problem, an audible hum in the
    I've tested the 7447t's filters and did not like the audio
    quality of them compared to using waves parametric eq.
    In terms of the sound quality of the mkh800, it is very practical
    to have switchable polar patterns, high output and wide frequency
    range, but how for example, it's use as an omni compares with
    Shoeps, DPA, Sonodore etc. would be better answered by
    those who have had a lot of experience with many different
    omnis, and would still depend on how each mic's particular
    signature helped or hindered a particular recording situation.
  4. ghellquist

    ghellquist Member

    May 25, 2004
    Hi Michael,
    thank you for the measurements and curves.

    I run a SD720 (edit: it should read 722) as my small rig. A stereo mic, stand and headphones and I am off to record. Quite a difference from my full car load of stuff. What I record is chamber music up to full orchestra + choir.

    Lately I have been using a Schoeps MSTC64 as my main stereo mic. Quite respectful sound in a very easily handled package. Other mics I have used included MKH20, MKH30+40, SF24, KM184, DPA 4007.

    I have never had any trouble with low frequency hiss from the preamps in any of the combinations. I record without HPF and add some filter in post processing -- buses and traffic are in that range. Doing the filtering in post makes it possible to vary the cutoff even during part of a recording, when that bus passes by for example.

  5. mdemeyer

    mdemeyer Active Member

    Dec 22, 2004
    Dublin, CA USA

    I thought the 744T was a great design because it could take 4-channels of AES/EBU (very hard to find feature), which is enough to handle 90% of my concerts when combined with a 3U rack holding my mic pre and A/D. The extra flexibility of a very small, battery-powered stereo package as you mention will be great for those fast and simple setups.

    Aside from cost, which is not low, this is an awesome piece of gear and really shows its professional heritage in build quality, usability, and features.

    I'm surprised I don't see more about them on this board.

  6. aracu

    aracu Active Member

    Sep 27, 2005
    A cool thing about the 722's is how they can be added
    together for a truly portable and cost effective way of
    adding more separate mic tracks.

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