To me, some of the most interesting stories come from one specific form of conflict: when a character’s ideology clashes with his or her principles. I’m writing such a story right this very now. I am that character. And if you’ve read my review of the Onkyo TX-RZ30 A/V receiver, you might already have a sense of why.
Ideologically speaking, I’m opposed to one specific trend plaguing our economy, whereby nobody really owns anything, where services have replaced products, where virtual licenses purchased for the full cover price of a book merely give us access to the text of the book that can be taken away at any time, where we literally need subscriptions for apps to keep track of all the subscriptions we’ve forgotten we’re paying for every month.
Now—on principle—why do I feel this way? It simply comes down to the fact that these things are generally bad for consumers as far as I see it, and especially bad for the working class. It’s mostly for that reason, and that reason alone, I have a built-in bias against something like Dirac Live Bass Control, an add-on license for a bit of software supported by more and more AVRs (and, indeed, even some stereo gear) these days.
To be fair, Dirac has gotten a lot more reasonable with its pricing as of late. Instead of charging you per subwoofer, the aforementioned TX-RZ30 supports a license that unlocks Bass Control for as many subs as the AVR will handle (in this case, two) for $299 (all prices USD).
The question, though, is this: is an alphanumeric code that unlocks capabilities already built into the hardware of the component you’ve paid good money for worth $300? Before putting Bass Control to the test myself, with my own speakers in my own room, I would have been inclined to compare it to BMW’s greedy scheme of charging owners a monthly subscription fee for the privilege of using the seat warmers already built into their cars, albeit only once instead of recurring.
Then again, AVRs aren’t cars, acoustically-iffy home-cinema systems aren’t the same thing as frigid tushies, and everything Dirac is doing represents the output of some serious ongoing R&D that needs to be paid for. So, when I said in the conclusion of the Onkyo review that I’m genuinely struggling with all of this, I meant it.
But what exactly is all of this software, what does it purport to do, and does it do it? Let’s start by discussing one of the ways room correction software typically works. For that, we’ll look at the Dirac Live capabilities of my reference NAD C 3050 integrated amplifier.
In the image above, you can see what Dirac Live does to my reference Paradigm Studio 100 v.5 tower speakers in my two-channel listening room when I let the room-correction system run full-range, from 20Hz to 20kHz. What might not be clear from the image is that it creates a correction curve for the left and right speakers based on how those speakers perform in the room, with the thick gray line (outlined in blue) representing its target curve for the speaker system. The light blue line represents the actual in-room response of my left speaker in the room, and the thicker, squiggly blue line represents what happens to the response of that speaker when the filters are actually applied and theory becomes practice.
Notice that the room correction applied to my left and right speakers behaves as if there’s no subwoofer in my system. It’s doing what it can to make those speakers conform to a full-range target curve, and thankfully, the Paradigms take well to that.
Here’s the thing, though: I did have my subwoofer turned on in the C 3050’s settings at the time, and Dirac Live measured it. And then it did its level best to calculate filters that would make that sub (an SVS PB-1000 Pro) perform to the best of its ability in my room, irrespective of what the main speakers are capable of. The thick yellow line outlined in blue represents Dirac’s calculated target for the sub, the thin blue line is how my sub actually performed in-room before filters were applied—but within the range the filters cover—and the results post-filtering are represented by a thick blue line that then gets covered in yellow outside the range of the filters. But again, none of those filters were calculated with any regard for what my main speakers are doing in the room. The subwoofer is, for all intents and purposes, treated as if it were operating in isolation.
Then what happens is the bass-management system of the BluOS-D module in my C 3050 puts a high-pass filter on the post-Dirac output of the speakers, as well as a low-pass filter on the post-Dirac output of the sub—each centered on whatever crossover frequency I choose—and the filtered output of my speakers below that point and my subwoofer above that point are rolled off. Meaning that much of the DSP that went into tweaking the frequency response and impulse response of both speakers ends up on the cutting-room floor. And before Dirac Live Bass Control, that’s just how all of this worked. So what’s different about Dirac with the $299 Bass Control license unlocked?
Here’s a look at Dirac Live with Bass Control doing its thing on the Onkyo TX-RZ30 AVR I just reviewed, in this case with an RSL CG3 5.2 system connected. And here I’m showing you a before shot, taken before filters were calculated, but during the process of designing the target curve for these speakers in this room with this receiver.
If it’s not obvious what’s going on here, this doesn’t involve setting a target curve for each speaker pair, but rather a target curve for each speaker pair + the subwoofers. So, running this system 5.2, there’s one curve for the front left/right + the dual subs, the surround left/right + the dual subs, and the center + the dual subs. What you’re looking at above is the first of those three.
Now, the thing about the CG3 system that makes it a challenge to integrate is that the low-frequency extension of its satellites isn’t always sufficient to sum with the subs at anything resembling a reasonable crossover point, depending on your room. I have, in the past, crossed these speakers and subs over at frequencies as high as 150Hz just to get them to sum.
What Dirac Live with Bass Control does, on the other hand, is look at the capabilities of both the satellite speakers and the subs and says, in a sense, “Hey, if I extend the response of the subwoofer a bit whilst considering the capabilities of these speakers working together in this room, with the gain provided by the walls, etc., and if I bring these speakers and subs into phase with one another, I think I can achieve a lower crossover point here and get these groups of transducers to sum.” That’s assuming that Bass Control wouldn’t use the royal or editorial “we.”
Of course, as we’ve seen in all of these examples, a smooth target curve is merely a suggestion. What happens when the system does the hard math and actually applies the FIR and IIR filters required to get the speakers as close to that target as possible and co-optimize their phase? The above is an example of how close it got in actual practice in my room. The darker salmon line shows the actual summed output of the subwoofers plus the left and right front speakers.
Mind you, there were some dips at around 80Hz and just above 100Hz, and when I saw those, I started tinkering with the crossover frequency and target curves to try to eliminate them, but I ended up going back to Dirac’s initial recommendation. And when I started throwing test material at the room-corrected system that would reveal any audible dips in this region, I couldn’t hear them. So I guess they’re either high-Q enough or low enough in amplitude that they aren’t audible with regular listening material.
Curiously, Dirac Live’s bass management set the crossover point of my center speaker higher than I normally would. 85Hz has always been a nice-sounding crossover point for me, since the CG23 speaker’s low-frequency extension is specified as such. But the 94Hz crossover calculated by Dirac Live sounds, to my ears, even better. And being able to see the in-room measurements of each speaker in the system really gives a sense of why. The in-room response of the speaker (seen here in light blue) really starts to plummet below 90Hz, perhaps because in my setup in this room, it’s a bit farther from the wall behind it than expected.
Indeed, having access to all of the in-room measurements while double-checking the algorithm and making tweaks is absolutely invaluable. Granted, it’s the sort of thing that could be done with Room EQ Wizard or similar software. But DIY software of that sort doesn’t really give you the same horsepower in terms of frequency- and time-domain DSP, and it’s a lot more work and takes much more time.
The long and short of it is, the results speak for themselves. I’ve never gotten the performance out of these speakers in this room that the Onkyo TX-RZ30 plus Dirac Live Bass Control gave me. And it’s astonishing to me that you get all of this for $1199 (although I’ve never seen the RZ30 sell for more than $1099) plus $299 for the Bass Control unlock code.
As I said above, my principled objection to tack-on software unlock codes is that they’re almost always bad for consumers, and especially bad for the working class. But in this case, I’m struggling to imagine how a working-class DIY home-theater enthusiast could get better results for the same amount of money.
It got me thinking that, instead of viewing the Bass Control capabilities of the Onkyo TX-RZ30 as a hardware feature that’s locked behind a paywall, perhaps it makes more sense to think of the AVR as a computer that’s capable of running this optional program, if you want and/or need it. And if you don’t, that computer just costs $300 less.
Is that copium I’m imbibing, in an effort to make excuses for selling out my values? You could accuse me of such. But I don’t think it is. I think when you view the TX-RZ30 as a platform that works great out of the box but can also support this incredibly powerful room acoustics tool as a wholly optional feature, it changes your perception of the thing. At least it did for me.
What really sold me on this approach, though, was a simple question I asked myself: would I pay $300 for a black box that has this transformative effect on the sound of my speakers in my room? In a heartbeat, I would.
Does the fact that it’s a string of digits I had to plug into a box in a web browser make it less of a value? My ideology would lead me to say yes. My principles, however, tell me that it’s every bit as good a bargain.
. . . Dennis Burger
dennisb@soundstagenetwork.com
