Adding in the Subwoofer
The next step is to add in the subwoofer. As I'm feeding the I2S output from the PCM2707 to the TDA1543 and both Opus PCBs simultaneously, it's possible to use the TDA1543 output solely to drive the subwoofer. The Opus DACs will be used with the 300Bs and Transparence speakers maintaining a crossover-less setup for the midrange and highs.
The Linnn Isobarik 5150 is configurable to crossover between 41-81Hz in variable steps. I started off at 41Hz initially, but found that the sub gave away its corner of the room location frequently when rendering sub bass. I'm out of space in my main living room and with the Linn being quite the behemoth, there really is nowhere else for me to put it. Crossing over at 48Hz seemed better to my ears, so we'll proceed to look at the room response with the sub in place.
Opus plus Sub |
That's better; we now have a decent response to around 25Hz. The nature of the Linn sub in my room is quite "boomy" and the bass lacks definition, even with a minimal amount of gain (possibly due to placement). Crossing the unit in a little higher does help with this, but then things get lumpy around 60Hz where there's already a peak from the main speakers. It'll be interesting to see how applying DRC will level things out.
Opus plus Sub with DRC The wonders of DRC - a predicted near flat in room response between 25 Hz and 15 KHz. |
Now we're talking! A predicted response most of us dream of at the listening position. The correction file was hastily loaded into Convolver and a few tracks played to see how things sounded. At the risk of sounding like a salesman, I can tell you I was pretty knocked out by the results. The integration of the subwoofer is almost seamless, only hinting at its location on the very lowest notes. All the perceived boom factor from the bass is gone. What remains is the tightest, most articulate bass I've heard outside using my Sennheiser headphones. I already knew the Supravox drivers in open baffles had real promise, but armed with DRC and a subwoofer, they simply move up to another league.
Switching DRC on and off is pretty much a day and night change. Listening without the filters is almost torturous when you've been subjected to what is possible. It's not that things get fatiguing; it's just that everything sounds chaotic and bloated without DRC to correct the abnormalities. The sonic quality of both DAC kits combined with a PC as the feed has surpassed my expectations, far in excess of what I can recall from the HDA Xplosion card I dismissed as lackluster in my previous attempts of using a PC based front end.
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Christobevii3 - Monday, December 1, 2008 - link
What about using a dts/ddl sound card to output to a basic receiver?Rajinder Gill - Monday, December 1, 2008 - link
If going to the nth degree for 2 channel it’s hard to look past USB-I2S in async. For multichannel, a DTS/DDL card is perfectly adequate. Although I’d still use an external solution if I could find one.wolrah - Monday, December 1, 2008 - link
How do you figure I2S is any better than S/PDIF? S/PDIF supports up to 20 bit resolution at either 48 or 44.1 KHz, so it can carry a CD audio stream natively. The bits on the disc are the bits flowing out the optical port on the back of your gear of choice.In theory an I2S signal will be able to take more interference, but when we're talking optical signals in a home environment the kind of interference needed to make a difference would be on the scale that you'd never be able to listen to anything.
Goty - Monday, December 1, 2008 - link
Well that's easy to answer:Nope. I'll stick with my Martin Logans, tyvm.
wolrah - Monday, December 1, 2008 - link
In fact it easily can, because plain and simple reading from the disc itself is error prone. A one time rip to WAV or [lossless format of your choice] using cdparanoia on its insane mode output through a high quality sound card will be the same as or better than any silly 4 digit CD player.Even playing straight off the disc, there's no reason to believe any "audiophile" gear will play a CD any better than any other CD player unless there's a design flaw like a crappy power supply.
On the note of power supply, am I the only one who laughed at the bit about the battery vs. the wall wart? Who wants to bet that he's never double-blind tested that one. That's the wonderful thing with A/V gear snake oil, it's very easy to hear what you want to hear.
mindless1 - Monday, December 1, 2008 - link
I've hand-built amps for years and double-blind tested batteries and wall warts. Yes there is a difference. A good (read: overkill for anyone not into building audiophile equipment) localized power filter stage, if not localized regulation, would ideally negate the difference between the two power sources but that can also unnecessarily increase the build complexity, time, and cost.PS the battery is almost always inferior assuming the wart has proper shielding or is inadequate in capacity, and generally I refer to a wart as only a transformer and rectification stage, not trying to build an entire high precision linear regulation stage inside of it due to limited space and EMI.
Rajinder Gill - Monday, December 1, 2008 - link
Martin Logan makes electrostatic loudspeakers if I recall.I'm not sure where that fits into using a PC as a transport and for DRC. Unless you're refering to the approval of open baffle design loudspeakers using te supravox drivers?plonk420 - Monday, December 1, 2008 - link
this is surreal...my $20 Chaintech AV-710 just died in the last 48 hours. i've been trying to resist the Head-Fi audiophile talk and try to find cooler heads to verify whether or not i should go X-Fi or DAC (something silly looking like the HotAudio HotUSB1 or Silverstone), or try to figure out if i'm experiencing the placebo effect "falling back upon" my ALC883, which i can swear "doesn't sound as good" EVEN THOUGH i'm fully aware of the power of placebo.
i'm not sure i liked the mixed bag of positive and negative reports on (cheap) X-Fi vs Xonar vs X-Fi USB vs some DAC vs E-Mu 0404/0202
mindless1 - Monday, December 1, 2008 - link
Choose a Creative card for gaming sound effects. Choose a DIY DAC for highest audio quality at a reasonable price. Buying some cheap commodity grade DAC is a gamble, I'm not familiar with those two products you mentioned but generally in the consumer segment and price range you end up buying an idea, a type of tech but not excellence in that execution.MOtherboard integrated audio usually doesn't sound as good including one using ALC883, though someone with poor hearing or gear may notice the difference less and less depending on where the weakest link in the chain is and how bad it is.
Gannon - Monday, December 1, 2008 - link
I have an X-Fi and it's better then my audigy, mind you I got the more expensive version with front panel and the remote. I use it for everything and have never had a problem, though I don't use vista at all just XP.