To help people compare Forssell SMP-2 and Gordon Model 5 preamps, Mark Wurfl and I recently recorded a live modern music concert featuring piano and a variety of percussion instruments. Attached pictures show the venue and how the mics were rigged.
METHOD
We used two matched coincident omni microphones to feed one channel of my Forssell SMP-2 and one channel of Mark's Gordon Model 5. We put the Forssell on the left channel and the Gordon on the right.
The signal chain was Josephson c617Set mics -> PREAMPS -> Benchmark ADC-1 -> SD744T recorder.
Note: We are confident the microphones are equivalent and spectrally accurate. The matched 1/2-inch MK221 capsules are measurement-grade; Microtech Gefell certifies them to DIN Type I, which specifies a tolerance level for repeatable research. Josephson matches pairs, with amp bodies included, to perform equally within much less than a dB.
Mic cables were Mogami quad (2534) plus a 25 foot house snake of unknown quality. All interconnects were equal length Mogami AES/EBU (3173) or Mogami quad (2534).
CLIPS
There are six clips with two versions of each; one version is the original 24/96 WAV and the other is downsampled to 16/44.
To compare sounds by ear just open the WAV files and listen to the
left channel (Forssell) and
right channel (Gordon) alternately. To see differences in the PCM with an editor this format couldn't be easier because the samples are aligned.
Mark did a great job calibrating the gain stages within three tenths of one dB RMS; one amp is ~
.3dB louder in most of the clips. Listeners should probably compensate for it on playback as we didn't want to mess with the PCM in any way. The 24/96 clips are bit-for-bit as captured. To create the downsampled versions I used R8Brain PRO with linphase and ultra-steep settings. To requantize dither noise was added (IDR, 16bit, type 1, ultra shaping) before truncating. There was no other processing or adjustment for gain. A picture below contains amplitude statistics for each clip.
This link goes to Thomas Bishop's website where all the clips are graciously hosted.
Preamp Shootout Thanks Thomas!
Or you can use these links to access the clips individually:
96/24 versions
http://www.nomadicpro.net/FG_9624_clip1.wav http://www.nomadicpro.net/FG_9624_clip2.wav http://www.nomadicpro.net/FG_9624_clip3.wav http://www.nomadicpro.net/FG_9624_clip4.wav http://www.nomadicpro.net/FG_9624_clip5.wav http://www.nomadicpro.net/FG_9624_clip6.wav 44.1/16 versions
http://www.nomadicpro.net/FG_4416_clip1.wav http://www.nomadicpro.net/FG_4416_clip2.wav http://www.nomadicpro.net/FG_4416_clip3.wav http://www.nomadicpro.net/FG_4416_clip4.wav http://www.nomadicpro.net/FG_4416_clip5.wav http://www.nomadicpro.net/FG_4416_clip6.wav Please note that all the clips contain music that is owned and protected by copyright. They are provided here for educational purposes under the fair use doctrine. U.S. Copyright Office - Fair Use
GEAR WE USED
Mics -
http://www.josephson.com/pdf/C617set_ds.pdf -
http://www.microtechgefell.de/index.php/en/measuring-equipment/sound--noise/kapseln
Preamps -
http://www.forsselltech.com/#!/products/1 -
Gordon Microphone Preamplifier System
ADC -
The ADC1 - Benchmark Media Systems, Inc.
Recorder -
The 744T: Portable, Four-Track Audio Recorder with Time Code | Sound Devices, LLC