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test A/D D/A - without personal bias & without ears!
Old 12th December 2008
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Arrow test A/D D/A - without personal bias & without ears!


this thread/post is the followup of myrtlebacker post:
taked the file:

...and made some loop tests:

Roland MMP-2 ===> Roland MMP-2
"MMP-2 can only work AD or DA, two are needed for the loop test."
MMP-2 all bypass, no EQ, no compressor, no Mic/pre emulation,
just AD or DA.
with RME Hdsp9632 pci, buffer size was 1024, with AD+DA total sample latency was 1127 measured with free Voxengo Latency Delay Plugin.

In/Out +/-dB was near as perfect as i could. calibrated with free MDA Testone generator 1Khz Sine @ 0dB, no clipping in the converters. the Roland Outs are a bit hott than the Ins. so i had to reduce gain in the master digital fader in Sonar arround -1dB. = Signal was Hot.
I should had used the free SSL X-ISM to calibrate In/Out dB levels.

tested loops:
A) both Rolands with the RME SteadyClock(TM) from the s/pdif signal chained from the Hdsp9632.
B) both Rolands with Drawmer M-Clock DMS-1, s/pdif signal chained.
C) first MMP2 with RME SteadyClock(TM)==analog==> second MMP-2 with M-Clock.
D) +4dBu vs -16dBu with M-Clock = two tests with same clock.
E) original .wav file.
DDS turned off at all times in the Hdsp9632 settings, for better ext.wordclock thru performance.
nice 99.997% OFC Rca--to--Rca cables for s/pdif.
6x Meter XLR--to-->XLR DieHard cables full OFC, 24k gold plated contacts.
all machines exept the PC were plugged AC 120v to Furman AR-15 series II,
old PC. p4 1.6ghz 400fsb, compaq 4700
i like Roland MMP-2 becouse they have transparent mid-range.
maybe the highs are not like Mytek or hyped like behringer ddx3216, but the mid range its accurate and totally transparent, and i like the dynamic range, emu1820m has way better specs measured with audiorightmark RMAA, but to me the Roland MMP-2 sounds better.
some serial numbers have a +-2dB roll off in the freq. range., but anyway i like it.

also used Sonar 7 32bits with 64-Bit engine active. becouse sounds totally transparent in the mid range. the 32 @ 32 does not.

taked screen shots of the zoomed waveforms,
the original vs. the DA-->AD loops waveforms with diferent wordclocks, all test were @ +4dBu, and one at -16dBu.

the sine waveforms looks 99.99% flawless in all tests,
only screen shots of the Saw at start, and Saw at the end.

the test i didnt had the WordClock Module for the Hdsp9632, i had to use the s/pdif as wordclock, and made a serial chain.
Drawmer M-Clock--s/pdif-->MMP2.(A)-->hdsp9632-->MMP2.(B)==analog==>MMP2.(A)-->Hdsp9632

the wordclock signal was not paralell, but serial.

the serial signal: "thru" s/pdif wordclock/audio signals seems to add a bit of jitter in each step.
jitter & drift is less with parallel distributed wordclock.

anyway, here are the results:::
take note that all softwares render visually diferent the waveforms.
Attached Thumbnails
test A/D D/A - without personal bias & without ears!-dactest1.jpg   test A/D D/A - without personal bias & without ears!-dactest2.jpg   test A/D D/A - without personal bias & without ears!-dactest3.jpg   test A/D D/A - without personal bias & without ears!-dactest4.jpg   test A/D D/A - without personal bias & without ears!-dactest5.jpg  

test A/D D/A - without personal bias & without ears!-dactest6.jpg  
Attached Files

looptest, M-Clock Test2 -10dB, Rec (82).wav (1.23 MB, 562 views)

looptest, RME--_M-Clock, Rec (75).wav (1.09 MB, 505 views)

looptest, RME--_RME, Rec (77).wav (1,012.0 KB, 515 views)

looptest, Track 8, Rec (73).wav (1.26 MB, 559 views)

Old 15th December 2008
hey man thanks for doing the tests.
something is going on with steady clock..
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