Thought I would bring up an Okto DAC8pro "feature" that I have really come to enjoy that I have not seen discussed and did not consider before I purchased. As all signals are routed through the XMOS (even in Pure AES mode) you can use the Okto as an input in REW to measure each channel going in to the Okto. For those that use DIY active speakers this is really nice because it allows you to verify your DSP settings are correct and evaluate changes. This is especially helpful in evaluating overall DSP response when you have a variety of filters implemented (input channel EQ, output channel x-overs, output channel EQ). This is also helpful for those that have Dirac as it will show the overall DSP response from Dirac and other EQ/x-overs and allow you to judge how much overall boost / cut has been applied.
For example the screenshot below shows DSP response for a slightly modified LXmini with sub.
View attachment 136497
Michael
Hello Michael,
In
my multichannel multi-driver (multi-way) multi-amplifier project with OKTO DAC8PRO, I am also much interested in the same features and aspects as you mentioned.
I use software crossover EKIO in PC for stereo 5-way 10-channel operation to drive sub-woofers (L&R) (
SWs), woofers (
WOs), mid-range Be-squawkers (
SQs), Be-tweeters (
TWs) and horn super-tweeters (
STs), and I always carefully measure and confirm the frequency response (relative SPL) of each of the crossover channels;
1. in digital level within PC before going into DAC8PRO,
2. in DAC8PRO's analog output level,
3. in amplifiers' SP output level,
and of course,
4. in actual multi-way SP sound level at listening position using measurement microphone
In my case,
TWs and
STs are driven by one dedicated amplifier, so that I am using full 8 channels of DAC8PRO for active
SWs (amp in it) ,
WOs (driven by Yamaha A-S3000),
SQs (by Accuphase E-460) and
TWs+
STs (by Sony TA-A1ES).
If you would be interested, please visit
my post #321 there for
1.,
2. and
3., and
#318 there for
4.
Currently, I am also intensively working on
"Cumulative White Noise Averaging" for reliable (and fully understandable) measurements of frequency response in these four levels, as just shared
here yesterday on the analysis in the level
1., i.e. "in digital level within PC before going into DAC8PRO". I will soon further apply this approach for levels
2.,
3., and
4.
(Just for your info, I also shared my approach of "Cumulative Pink Noise Averaging" at
here and
here.)
Since Fq response measurement is based on the statistical FFT analysis, I believe that we should be careful enough on the sample size (total energy of the sound signals for analysis), method by r
apid sine-wave sweep, by
pink noise or by
white noise, selection of FFT size, and other smoothing algorithms (like REW's psychoacoustic smoothing) if applied.