How get the best sound out of your
SoundBlaster AWE 32
with or without an external DAC
Now with Win 95 specific comments!
Written by Mathias C. Hjelt
V2.0 - 16 Sep 95
There's a reason for everything. The reason for the AWE being so cheap is that
it is built up of cheap components. The reason for the AWE not being professional
is the same. Most AWE users (and obviously most GUS fanatics, too) are aware of the
somewhat noisy and cheapish sound of this card, but few seem to know how to improve
it.
The best way of making the AWE's synth sound as pro as possible and get rid of
all background hiss is to connect its digitial S/PDIF output to an external,
pro-quality D/A converter. However, doing this won't take you all the way to heaven,
but if you're interested in this stuff, check out my page called
"To go S/PDIF or not".
But there are cheaper (in fact, free of charge) ways towards a
cleaner and better AWE sound, and that's what most of this page is all about. It's
mainly about setting up the card correctly in terms of software, but there are also some
hardware factors that shouldn't be forgotten. The two first paragraphs also affect
the digital S/PDIF output. These are the topics that are discussed here:
Most of this is stuff that I've figured out all by myself. If you know any other
cool tricks that enhance the sound quality of the AWE, and would like to get them
added to this page, mail me and let
me know.
Digital noise - OPL-3 blues
If you're still using Win3.1 or 3.11, you probably also use the standard FM driver from
Voyetra. If you do, this is extremely important, no matter whether you are using an external
DAC or not.
As described in the short introduction to
the AWE hardware, the output of the OPL3 goes trough the EMU 8000 synthesizer, and that's
bad. As soon as the Windows FM driver (SB16FM.DRV) is loaded, it initializes the OPL3 in some
foolish way, which makes the chip start whining terribly, and turns the EMU output next to unusable
for serious people -- including those with external DACs.
The cure is of course very simple -- just make sure that no program (no sequencers,
not the MIDI mapper, nobody) loads the FM driver, either by doing a bit of configuring
or by uninstalling the driver in the Control Panel Drivers applet -- but it took a while until
I figured out where this darned digital, disharmonic high-freq whine came from, and as a matter of
fact I did not do it all by myself. Anthony Ruggeri once complained about having digital noise on his
S/PDIF output, and he told me that he suspected the OPL3 since it was the only non-EMU
component that was routed to the S/PDIF interface. Well, after doing tons of listening and
tweaking, I figured out that it indeed was the OPL3, and that it did not start before its
Windows driver was loaded. Wow, now finally I got rid of that very annoying whine that had
been bothering me since day one! I mailed Anthony and suggested he'd remove his OPL3 driver,
and his problems were gone too. For a very obvious reason, I felt pretty happy that day.
So there you have a bit of history. And the good news is that Creative put together a new
FM driver of their own which is shipped with Win95, and it seems like it causes no strange noises
when it's loaded, so if you really want to have access to the FM synth, you can have it now without
spoiling your EMU music. And they say that Win95 is no good!
Frequency response - how to fix it
Many computer mags and synth mags that have tested the SB AWE 32 have reported that it has
got a decent, but yet not fantastic frequency response. This only partly true, because of
this:
- The response of the wave audio channel's DAC is actually slightly better than
most tests tend to show, and that's because the regular "take a test signal, digitize it,
play it and measure" tests get affected negatively by the low quality of the ADC, i.e the
sampling section of the card. I won't, however, get into that here.
- As described in the short introduction to the
AWE hardware the synthesized stuff (EMU & OPL3) runs through a separate DAC,
which never (or very seldom) is tested in regular sound card reviews, although it is the
more important one for most AWE users.
- To make the whole thing even more complicated, the thing that affects the frequency
response of the synth output the most is not the on-board DAC, it's not any on-board analog
electronics at all -- it's an equalizer built into the EMU, and that's what this is all about.
I noticed that there was something wrong with the frequency response of the EMU when I was
importing WAVs into an SBK, and listened to the samples both through the EMU and through the
regular wave audio channel. The EMU-stuff was peaky. Lacked depth. The reverbs were terribly
hissy. Another thing that made me suspicious was that I always had to fiddle wildly with
equalizers and tone controls to make the EMU music sound good, while wave stuff sounded OK without
any bass/treble tweaking at all. And while doing some general EMU research, I noticed things
that were so weird I had to check them out more thoroughly, and came up with a frequency response
graph of the synth ouput:
Who's the black sheep?
As you can see, the frequency response is really weird (an increase of 7.5dB at 11kHz, which means
that the amplitude is more than doubled at that point, compared to a 1kHz signal). Not even C cassette
decks do so extreme things. At first I suspected that this was caused by the lousy on-board analog
electronics and hoped that the problems would disappear as soon as I got an external DAC, but they didn't.
By comparing the frequency response of the Reverb & Chorus effect to that of the QSound algorithm, I
noticed that this strange equalizing must be done in the Effects Engine, since QSound had a much
flatter response than the Reverb stuff.
The Reverb & Chorus algorithm should actually be called Reverb & Chorus & EQ, although only
the reverb and chorus effects can be controlled easily. The EQ is probably more advanced than only a
basic bass/treble filter, but that remains to be seen (and don't expect Creative to reveal any
info at all). By default, this EQ is set to boost the treble a whole lot to add "presence" to the
sound, probably to make the dull ROM-samples sound brighter. In my oppinion it does not make the sound
any better, it rather makes it very odd since the treble dominates way too much, the reverbs let
through too much high end, and the harmonic contents of the samples gets messed up.
It is - of course - possible to control this digital EQ from software. However, at this very moment
(16 Sep 95) there are no publicly available pplications that will let you change these parameters, and not
all drivers have support for it, but this is probably going to change soon. Here's what to do:
Windows 3.1 and 3.11
In version 1.27 of SBAWE32.DRV, dated 27 April 95, there all of a sudden was support for the
digital EQ. No comments from Creative, nothing - it just appeared. Since that date, there's been
support for it under Windows. However, there are no programs that will let you set up this EQ
in an easy way, you'll have to do it by inserting two lines in your SBWIN.INI and restart Windows.
In this .ini file, put in these two lines under the [AWE32]-header:
..where X is a value from 0 to 11. These numbers correspond to the boost levels -12dB, -8dB,
-6dB, -4dB, -2dB, 0dB, +2dB, +4dB, +6dB, +8dB, +12dB. For no boost at all, let X be 5 on both Bass
and Treble. This chops down the 11kHz peak from 7.5dB to about 1dB. The little bump that is left
can't be removed digitally, although it is produced by the EMU in a way or another. In any case,
it's so small that it won't hurt anyone, compared to the 7.5dB peak you get if you don't set these
variables at all. And oh, remember to get the latest drivers first (see below).
Windows 95
As soon as I tried out Win95 I noticed that there was way too much treble, and soon I noticed that
this was because the new driver didn't use the Bass and Treble settings available in SBWIN.INI. There simply
is no support for that. Instead, the new virtual driver file called SBAWE.VXD supports it in a way or another
- but unfortunately there's no way to control anything until Creative release some software
that uses the new implementation. Until that happens, you'll have to attenuate that peak using
an external equalizer, or the analog bass/treble tone controls of the AWE's mixer.
The old AWE Mixer application doesn't work properly, but SBVOL32.EXE ("Volume Control") which comes with
Win95 is a good replacement for it. You find the bass and treble controls if you enable the Advanced mode.
To get rid of most of that 11kHz peak, move the Treble slider to somewhere between the second and the
third mark from the left, perhaps something like 1/3 of the way, closer to the second mark. This equals
a TA: setting of 51 in CTMIX.CFG used by SB16SET.EXE. I used to have TA: 48 earlier, but you can't get
this setting by moving the sliders in the new SBVOL32 mixer, so you'd have to use SB16SET.
There are two problems with this: unless you have a really professional equalizer, you can never
eliminate this peak without cutting out other innocent frequencies. The sound will probably get
duller. The second problem is that not only the EMU music but all sound from the AWE goes through
the analog bass/treble control's so if you do this, you'll lose all treble from the wave audio stuff.
What about DOS?
The DOS API doesn't have any support for this, so you'll have to use analog equalizing like in Win95.
Is this really necessary?
Absolutely! It makes the EMU music much more balanced, the irritating high end is gone from the reverbs,
your samples sound like they were meant to. If you do external analog equalizing, you do not only get rid
of the peak but also wipe out lots of nasty background noise and digital noise at the same time, and that's
not too bad. The best sound I've ever got was when I had the digital EQ set up to boost the treble, and then
cut it down externally. This worked like a noise reduction system - when I halved down the artificially doubled
treble, I also halved the static background noise - both analog and digital. In any case, anyone who actually
cares about what the music sounds like should try this out - you won't regret it. Even if the first impression
is that there's too little treble, you'll soon notice that it's the other way around: it used to be way too
much treble.
Remember..
The digital EQ does not affect the wave audio channel at all. It only filters the stuff that goes through
the Effects Engine, and is only operating if you have the Reverb & Chorus effects type selected in
the AWE Control Panel. The QSound effect does not have the EQ code, so it's not affected by these Bass
and Treble parameters.
The analog tone controls, bass/treble, that can be controlled in the AWE Mixer or the new Volume Control
Win95 app, affect all sound coming from the AWE, since they are located in the analog mixer chip on the
output bus.
The wave audio channel doesn't need any equalizing at all, you can't improve it by moving the analog
tone controls. Leave them centered if you want a flat response.
Where do I get those new drivers?
At the moment, the official driver upgrade packet AWEUP.EXE on ftp.creaf.com contains the 1.27 driver for
16-bit Windows. The latest version, 1.28, is available in the ADIP - AWE Developer's Info Pack - which also
is on Creative's FTP. On some other FTP sites there are AWEUP.EXE files that contain older drivers, so you really have to
make sure you got the latest one. According to Creative, new Win95 applications and drivers will be released any day now,
and are probably out by the time you're reading this. For a link to those sites (including European mirrors), check out my
list of FTPs.
SNR in relation to the mixer volume and gain settings
Since the level of the AWE's line output is remarkably low, it feels tempting to boost it somewhat by
increasing the output gain factor to x4. This is, however, not a very good idea, since all amplifiers
on the card add considerable amounts of noise to the sound when cranked, and the output stage
is no exception.
But let's start in the other end. The synthesizer volume (EMU & OPL3) can -- and should -- always be
at max, to keep the SNR as good as possible. The EMU alone can not overload the mixer (unless
you've screwed up it's internal EQ a lot, for example by adding 12dB of bass), so there's no risk it'll clip
even when it's cranked like this -- and I'm really not interesting in what happends if the OPL3 starts blasting
too, because that chip gives me the creeps anyway. If you think the music is too loud, turn down the volume of
your amp or the AWE's master volume, not the synth channel's volume in the AWE's mixer.
I have never noticed any clipping caused by the wave audio channel playing with its volume cranked
to max, but I doubt anyone want to have it that loud, because it's pretty noisy (read more about
that in another section coming up). However, if you want as good SNR as possible on it too, keep it
cranked. If you don't use wave audio that often, I suggest you keep it muted by default.
Now, make sure the output gain is at x1 for both Left and Right, and then set the Master volume to
something pretty high. The master volume itself does not change the Signal-to-Noise Ratio very much,
because little noise seems to be added after this final volume control, but the gain factor really makes
difference. Not revolutionizing, but even a small improvement is welcome, right?
Worried about too low output signal after doing this? Don't worry, just read the section called
"Connecting the AWE to an external amplifier" which is coming up soon.
NOTE: The S/PDIF output is not affected by the settings of the AWE's mixer.
The input channels (mic, line, CD, PC-speaker)
The AWE has got several inputs, which all are connected to amplifiers -- and all amps on the AWE tend
to be noisy. That's why these inputs have been discussed so much, especially by those who love the
GUS vs. AWE war. Suckers. The truth is that most inputs actually aren't much worse than the rest
of the card, and don't add that much audible noise.
But let's start with the embarrasing part. The Mic input is, sad but true, what you
could call extremely bad. It's amazing that CL managed to make anything that bad. It literally drowns
in hiss. Never use this input -- always keep it muted, and never route it to the recording bus
unless you really want trouble. If you want to record something off a mike, use an external pre-amplifier,
as described in the page dealing with how to sample
best with the AWE.
The Line input -- this is the input you're supposed to be using if you want to input stuff
from external audio sources, and if you use it right, it can pretty good. The volume controller does not
affect the noise level that much -- I haven't been able to reliably register any difference -- and in fact
I'm not sure wether it's a good idea to keep it low and compensate by boosting the external signal level
or not. In any case, you are always going to be confronted with a little amount of noise (both regular
white noise plus some nasty leakage from surrounding digital stuff) as soon as you take this input in use,
so if you don't need it, mute it.
The Line In can be used both for sampling and for mixing the output of some other synthesizer or audio
source with the AWE's stuff, having it all coming out of the AWE's line out. In the pass-thru mode, i.e.
when the line input's little green dot is enabled in the Windows Mixer, it behaves perfectly in terms of
frequency response (Line In to Line Out). If you accept an 1 dB attenuation in the extreme ends, the frequency
range is no less than 2.5Hz to 150kHz. The only reason why you shouldn't use this as a
mixer is that you'll have AWE-noise all over your signal, even if all other AWE-channels are muted. This
is, however, mostly caused by the lousy final stage, and not that much by the line input amp. (Note that
a good line input does not automatically mean that the sampling is good too. Check out the page about
how to sample best with the AWE, and you'll see
what I mean).
The CD input seems to behave pretty much like the line input, although I haven't tested
its frequency response. The PC-speaker input doesn't seem to be very noisy, probably
because of little or no amplification at all it is subjected to. This is, however, no reason for leaving
them cranked if they are not needed.
Conclusion: Only enable inputs when you need them, never ever use the mic input, and
everything will be just fine. It seems like all those who moan so much about the AWE's terrible inputs are
addicted to high gain microphone inputs, and do all their so-called tests with all inputs floating around
un-weighted, un-loaded or un-grounded, just to simulate maximum anti-reality. Oh well..
Wave audio channel problems under Windows
For some reason, Windows does a lot of bad things with the wave channel. For instance, after finishing
playing a sample that does not end on zero level, it leaves the DAC in some strange state that makes it
output a constant high freq whine, which does not stop until another sample is played. So if you notice
that there's an annoying amount of digital noise on the wave audio channel, just play a short, silent
WAV trough it, and it is likely going to shut up.
The VU meters and the "scope view" of the AWE Mixer that monitor the signal on the recording
bus should be avoided. They induce a great deal of irritating digital noise on the wave audio channel.
The spectrum analyzer is not as bad, but instead rather useless.
If anyone knows how to get rid of the damned pops that are generated every time the wave channel is opened
or closed, let me know. I hoped this problem would disappear when I installed the updated drivers, but
nope.
Another thing that still is bothering me is the fact that whenever the CSP is taken into use or closed,
it makes odd noises. To avoid lots of crap when playing samples, don't keep them compressed. (Compression
in general makes the sound noisy - not only a-law, FastSpeech and those, but also the ADPCM algorithms
mess up your sounds, so avoid them if you want clean samples.)
Unfortunately, there is no way of removing all of the regular hiss and noise from the wave audio, except
from muting the whole channel. Playing a zero sample will only remove the left-over crap from the DAC,
and nice tricks like the EMU-equalization won't work since the frequency response doesn't in fact need any
fixing at all.
Connecting the AWE to an external amplifier
Since the level of the line output is so low (especially after reducing the gain factor to x1) and the
on-board-amplified speaker output is completely useless, you have to connect the AWE to an amplifier
capable of boosting the signal considerably without adding noise. If you connect the AWE to a regular
line (aux) input of a regular stereo system, you're probably going to have to crank the stereo's volume
way up high, much higher than you'd have for regular audio sources, and this is likely going to add a bit
of unnecessary and unwanted noise. This is one of the reasons why so many are convinced that the AWE is
incorrigibly useless because of its hiss, while I claim it isn't.
So what you need is an amp, a stereo kit or whatever, with a low-noise pre-amp stage. To find out if
your amp has got such a thingie, connect it to the AWE (which of course runs at gain x1), let the card play
some music, and crank up the amp's volume so you get a pretty normal output level, or maybe slightly
higher than normal (with "normal" I mean the average volume you usually play music at). Now turn off
your PC, but don't touch the amp. If you hear any hiss at all now, it's caused by your amp alone, not
by the AWE.
Even if you buy a semi-pro mixer to be able to mix the AWE with other synths and audio sources, you can
run into the same problem -- increasing the input volume/gain somewhat to compensate the AWE's exceptionally
low line output level may add hiss, that in fact has got nothing to do with the AWE's own hiss. This, and the
fact that such mixers can cost quite a lot, made me wire up my own combined no-noise mixer & headphone amp.
Using this, I noticed that the AWE actually was a lot more quiet than I had used to believe earlier when
I ran it through my cheapish Panasonic stereo. However, the mixer did not turn out to be as perfect as it should
be, so the schematics aren't available yet. You can't build a Mackie just like that.
Many cheap stereo systems often do a lot of stupid equalizing to compensate the lousy frequency response
of the bundled speakers. If your stereo boosts the treble by default, it'll of course also boost the AWE's hiss,
which will be very annoying if you connect it to high-quality speakers or headphones. Strange stereo
enhancers and such stuff may also mess up the sound in a negative way. So watch out with these machines
if you want to keep your AWE clean.
Some people claim that the mini-plugs that are used for all the inputs and outputs in the AWE's back panel
add noise. Bad excuse. How come the noise disappears to a great extent when the AWE's master volume is
cut to zero? Does this change the nature of the mini-plugs? No, let's face it -- it's the on-board electronics
that suck. (Atleast the output jackets of newer AWEs should be treated as innocent -- I have received comments
from users with old AWEs that claim they really have experienced plug-noise.) However, you should pay attention
to the cables you're using -- make sure they are properly shielded and grounded. If you have more than one sound
card that is connected to the same amp/mixer, watch out for ground loops. You may have to leave out the ground
from one of the cards' audio cable. Even if you have no other PC-card than the AWE alone connected to the amp,
you can run into trouble with grounds, caused by a left-right loop. This isn't very likely to happen, but if you
get unresonable amounts of strange noise, try removing the ground from one of the channels' (left or right)
connectors (the ones that are to be plugged into the amp/mixer/stereo).
Physical card placement
I was surprised to see that the physical card placement didn't affect the AWE's noise level very much at
all. I tried moving it closer to and farther away from other cards, and experimented with inserting extra
shielding plates between the cards, but there were no dramatic changes in the static noise level.
However, when I placed the AWE in the slot next to the I/O card, I finally found some interference. The
ribbon cables to the harddisk and floppy were pressed against the soldering side of the AWE, and fell loosely
down over the component side. This resulted in nasty pops, rattles and such noises whenever the drives were
accessed and data flowed trough the cables. In addition to that, mouse movements could also be heard clearly
when the volume was cranked. There was no noticeable increase of the static noise level, though.
So if you want to avoid leakage and interefence, move the AWE as far away as possible from cards like I/O
and graphics. Putting in an isolated(!) shield between the AWE and the rest of the machine could be worth
trying out. However, unless you have very noisy cards in your machine, this isn't very likely going to affect the
static noise level noticeably, it'll just decrease the amount of irregular interference peaks.