SirNickity wrote:I'm also curious how the SB Pro compares -- at least within its limited specifications.
Despite using an appropriate 8-bit, 44kHz (mono) test WAV, the figures that RMAA is reporting for the SBPro2's noise level and dynamic range are nonsensical. I'll have to revisit this, as I'm either doing something wrong that I have yet to account for, or the software is simply unable to interpret the data correctly.
On an unrelated note, I figured I'd check to see how a treble value of 0 (-14dB) on the SB16 compares to the default 3.2kHz cutoff filter of the SBPro/Pro2.
Sound Blaster Pro 2, 3.2kHz cutoff filter - 8-bits per sample MONO 44.100 kHz PCM

Sound Blaster 16, -14dB Treble - 8-bits per sample MONO 44.100 kHz PCM

Comparison recordings of the above:
Gotta love the "approximate" 44.1kHz playback rate of the Sound Blaster Pro 2 example...
Unsurprisingly, the filtering effect of the SB16's treble reduction isn't nearly as pronounced as the Pro's low-pass filter. At the same time, Creative's suggestion of reducing the treble to mask some of the 8-bit playback issues seems slightly less lame. That is, it's still lame, but more effective than doing nothing at all.
Am386DX-40 wrote:You sure it's the mixer chip revision? Take a look at this: My Sound Blaster 16 CT2230 Review
Of the cards represented, only the CT2290 bears a CT1703 CODEC. The commonality in this sample set, as relates to the THD/IMD metrics, is an "A" mixer chip (CT1745A, and CT1745A-S). Preliminarily speaking, dash-following suffixes don't appear to be particularly meaningful (e.g. an "-S"), but a larger set of metrics and comparisions should help clarify that.
James' observation of mixer channel settings of -2dB producing the optimal SNR is pretty spot-on, and is reflected in what I'd arrived at for the tested mixer configuration:
/MA:240;240;50
/VO:240;240;50
/MI:0;0;50
/CD:0;0;50
/LI:0;0;50
/MIC:0
/SP:0
/TR:128;128;50
/BA:128;128;50
/IPL:MIC- CDR- LIR- LIL- MIR- MIL-
/IPR:MIC- CDR- LIR- LIL- MIR- MIL-
/OPS:MIC- CDR- CDL- LIR-
/AGC:-
/IPG:1,1
/OPG:1,1
/SE:- (where applicable)
Scali wrote:Another observation is that the CT1740 seems to have completely horrible stereo crosstalk.
Where the tested CT1740 is a pretty early version (rev. 3 PCB, CT1745 mixer), I suspect that same-model cards with later PCB designs and/or a CT1745A may fare better in this regard. I have a couple of additional CT1730/1740 cards to test yet.
rasz_pl wrote:are those stock setting, or with massaged mixer?
Answered above. Recall that I'm trying to establish an "optimal" baseline.