i just ran some RTA tests today of my SVT using the TrueRTA program which allows up to 1/24th of an octave RTA testing of any preamp, amplifier or speaker cabinet. the results were kinda surprising.
the amps/preamps that i tested in this run were my SVT-VR, my Universal Audio 6176, and my Avalon VT737SP preamp.
the first graph is a test running pink noise into them and testing them directly from their preamp outputs. This first graph shows them at a 1/3rd octave so you can get an idea of how similar they actually are, with all of them set flat.
(
the SVT is the green line,
the UA is the blue line, and the
Avalon is the purple line):
the next test was using the speaker output to see what happens when you place the SVT's power amp, and the Crown xti2000 (for the UA and Avalon) into the equation. This was done with a direct box with the 'speaker thru' patch and using the direct out, into the RTA program. (this time the
SVT is Blue,
the UA is green and the
Avalon is turquoise):
in this case, the SVT's results were, by far, the best, as you can see that the crown has as pronounced dip at around 80Hz, so after seeing that, i went into the crown's DSP software and gave the crown a 4.5 db bump at 80hz to try and flatten it out for the next test.
The final test was to use a calibrated B&K 4006 with pink noise in front of my EL Whappo Jr. cabinet, running the TrueRTA at 1/24th of an octave. By looking at the graphs, although i love the sound of this cab, its obvious that it isn't anywhere near completely flat, but the SVT just sounds wonderful thru it (as do the others).
here's the
SVT (orange) as compared to the
Avalon (green):
as you can see, they are almost an exact match now!
and here's the same test, only using the the UA 6176 instead of the Avalon. in this graph the
SVT is orange and the
UA 6176 is turquoise:
keep in mind that these tests are just for frequency response only, and do not demonstrate the dynamics or 'feel' of playing thru the amps. even though the Avalon matches up a little better on the graph, the UA actually 'feels' more like the SVT with a bass plugged into it.
what these tests also show is just how much a speaker cab (in this case, an Accugroove EL Whappo Jr-the newest version) 'color's your sound, with its largest dips being at 1Khz, 2Khz and 8Khz.
i hope that some of you might find this info helpful.
