I, too, dislike the idea of calling bass response "slow" and prefer the term underdamped. I also like the idea of multi-sub arrays and have experimented with variations on the theme pursuant to some great posts by Duke of Audiokinesis, so I agree with a lot of this post, but....
Spkrplus wrote:
A properly installed Distributed Array has no integration issues up to about 80 Hz because it solves the bass mode before it occurs. All other solutions are band aids attempting to fix the mode after the fact, including EQ, which can't solve the timing error.
If "no integration issues" means "no room integration issues", this is an overstatement. You won't remove room effects with four (or more) subs, but you can greatly reduce their impact on direct FR and power response with careful placement. As a side note: EQ fixes the problem before it occurs, too. Once EQ filters are set by room analysis, the subsequent electrical (music) signal is adjusted prior to reaching the driver. Tho the filters are calculated "after the fact", that does not a band-aid make. If you doubt that this approach works, simply do an RTA of the direct and power response in the room (I use white and pink noise) post EQ. The benefits in both graphs are obvious, tho usually more dramatic IME on FR than power response.
The difference in power response improvement is - to me - the primary conceptual benefit of an array vs EQ, but per my own measurements, I wouldn't personally describe that delta as dramatic. My own array experiment - admittedly not ideal, two Velodyne SPL 8s and two 12" Rythmiks optimized for power response - showed power response improvement over the dual Rythmiks, but not wildly different. In fact, the power response and FR performance of that array was clearly improved by the application of Audyssey, too.
Proviso - a different subwoofer array implementation might yield different results, but my attempt was reasonably diligent. Had I gotten more dramatic results, I'd likely own an Audiokinesis array right now. To be clear, I wouldn't bet against me buying one in the future, but I'll still use Audyssey with it.
As for long wavelengths reflecting off boundaries (2 bass players), this happens with distributed subwoofer arrays as well as single subs. As a technical matter, it happens more - reflections for each sub are inevitable (4 or more bass players). Careful placement of the subs relative to the walls can smooth the response anomalies caused by each of these reflections, but they're simply smoothed in aggregation, not removed.
It's also unclear what "timing error" EQ can't solve. If you're talking about decay characteristics of the room, I don't see how a sub array would be helpful there either.
As for in-wall woofer solutions, they do effectively address the issue of reflection off the wall behind them (this is generally the worst IME) but there are still side wall, floor and ceiling issues which are certainly not trivial.
To be clear, I'm not dissing the idea of subwoofer arrays. I actually think it's a great idea. I'm just pointing out that the particular benefits of an array are overstated in this post and the objections to EQ are also overstated. Of course, the bottom line is a listening session. IME, thirty seconds with Audyssey should be adequate to demonstrate the benefits to most people (simply disable it during play). That doesn't mean it's preferable to a well implemented array, it just means that it's a very effective solution for the bulk of the problem. The best practical solution that I know of is an array with Audyssey, but, if you really want to "fix" the issue, an anechoic chamber (or room that effectively behaves as one) is the only solution that I'm aware of. |
IMO, a well executed subwoofer/mains system is very hard to beat. However, the "well-executed" part is the trick. All of the best sub implementations that I've heard use digital bass management and/or room correction and a lot of folks here won't go that way on principle.
If that approach bothers you, I'd agree that you might want to pass on adding a subwoofer. BTW, I'd never add a sub to Verity speakers (I own P/Es), unless you plan to ditch the bass pedestal units. The Parsifal design is terrific, and I love mine, but IME they are not designed for flat, extended bass response. Adding a sub without some EQ in the mid-bass would almost surely be a mess and, even with EQ, the octave to octave balance of the speaker would be substantially altered. |
Elegal,
Those do exist. Duke at Audiokinesis makes a really interesting speaker system with your choice of two different subwoofer arrays, one sealed the other ported. There are four subs with four channels of amplification in either array. I think it's worth visiting his web site to check out.
There are also traditional 2.1 systems out there, tho not as many as there once were. |
Lewinski,
I've used several active x-overs and I divide them into 2 groups. The analog models included a tubed Marchand, an NHT x-2, and the internal active x-over in my Theta Casablanca. The Marchand was too noisy for me, but that might be unique to that piece, rather than the model, since I've been told that others had more success. The NHT is an excellent piece (and IMHO a great value), but I ended up pairing it with a Velodyne SMS-1. The resulting performance was excellent, but the set-up was a giant PITA (thanks to the Velodyne) and the multi box/cable arrangement was inelegant. The Theta is a really flexible and good sounding unit, too - and a one box solution.
I moved to an Onkyo 5509 pre-pro after I heard Audyssey xt-32. A lot of A/B testing at a couple of local places led to a loan of an Integra pre-pro which I felt was (much, to my taste) superior to the Theta. The crossover in the Onkyo (like most modern pre-pros) is effected in the digital domain. I ended up buying the Onkyo version because I couldn't hear a difference in sound between it and the Integra version, it was significantly cheaper, and I preferred its appearance.
To the x-over question: It's hard to separate the performance of the digital x-over (vs the analog x-overs) because they were integral (pardon the Onkyo Integra pun) parts of two very different pre-amps/pre-pros. In the end, I like the Audyssey powered one-box solution of a pre-pro for my main 2 channel system and that means a digital x-over comes as part of the deal. Whether it's the digital cross, the room correction, the balance of the preamp circuitry, or any combination of the above, the bottom line is that I found it to be a better mousetrap. Since I had already effectively stopped listening to LPs in favor of a server (and consequently didn't really have to deal with the cognitive dissonance presented by ADC and DAC for my analog LPs) I retired my ARC LS-25 and Joule LA-150 without much indecision. As always, YMMV.
Hope that helps. BTW, I've never heard the Dirac correction package, but I've done a bunch of research on it: There's definitely some interesting software there. If you do pull the trigger on Dirac, I'd be grateful if you posted your take on its performance. |
Lewinski,
I've used several different configurations, but I'm currently taking the digital signal out of my QSonix server straight into the Onkyo via coax. The Onkyo does all DSP including x-over. The twin sub out of the Onkyo goes straight to my Rythmik subs and the main out goes to (at the moment) a pair of Cary 805s and on into a pair of OHM 100s. Sometimes, there's a different amp/main speaker combo, particularly if I'm using my Maggie MMGs, which require more grunt than the Carys can deliver.
BTW, I've previously used both of my current stand-alone DACs (Cambridge DAC Magic and Benchmark) for conversion, but - as I've noted - simplicity is important to me and I prefer the simplicity of one box. As to SQ, it's audibly different with each DAC (especially Benchmark vs Cambridge) and a matter of personal taste, but I like the sound of all three options and settled on the internal Onkyo DAC for the reasons stated above.
Further, BTW - there's an upgraded version of the Onkyo from one of the specialists (Upgrade Company?) that offers an in-home trial. At the moment, I'm kicking the idea of a trial around just to check out any potential improvements. If I pull the trigger, I'll post my impressions |
Sorry, I missed the other half of your question. The configuration you describe might sound great, but it's (not to beat a dead horse) a little complex for my taste. In your shoes, I'd personally be inclined to look at something like the HK 990, which provides all the DSP (including x-over) and amplification in a single 2 channel box. As a bonus, it includes room correction, so you could A-B that against the Dirac to see which you prefer.
To be clear, that isn't a recommendation (tho I've heard and like the HK 990 quite a lot), just a simpler alternative that I'd likely pursue given my own particular priorities.
As to the required second DAC in the set-up that Dirac suggested, I can say that the Cambridge represents good value IMO. |
My Parsifal (Encore) barely makes the low 40hz range WITH the woofer cabinet - they start to quit in the mid 40s range and are well down by 40hz. The monitors start to roll off at about 55 to 60 hz in my room. There's a hump in the upper 40s thru the crossover region to the monitors that gives kick drum some extra (ahem) kick and a satisfying sense of bass with almost all music. Not exactly textbook accurate, but I love 'em with most program material, just not for the deepest bass.
I guess YMMV |
You're not the only person to mention the "expanded space" phenomenon. I'm not sure I've ever really experienced it, but it makes some sense if the sub is providing very low level bass throughout the room and that is perceived as ambient special information.
My post was focused more on your chosen x-over point and my guess is that the effect you describe is probably (I'd think) independent of that choice. |
Lewinski,
The DEQX has always looked interesting to me, but the local dealer (possibly also the national distributor) isn't very accommodating, so - even tho I tried to stop in for a demo - I never got a chance to check it out and can't really comment. It's gotten some good press, tho.
I know zero about the QOL and never thought it was designed for this application, tho I'm not sure what it IS designed for.
If you decide to keep the Lamm, my guess is that you'd be best off passing on subs unless you want to run separate 2 systems (or dual front ends). I don't mean to spend your money, but...
The good news is that +/- $2700 buys an Onkyo 5509 with Audyssey xt32 and a pair of 12" subs from SVS. That's a set-up that I'd be happy with and it's a modest investment relative to the LAMM. It would allow you to swap the amp and sources between the pre-amps on the fly (once you've attached the subs and set-up the DRC on the Onkyo), but you have to be the type that wants to repeatedly rewire the system.
I was that guy at one time, but not anymore - and I certainly can't speak for you. |
Lewinski,
If you need an inexpensive, sand-alone active x-over, see if you can find an NHT x-2. It's now discontinued and hard to find (probably because it's pretty widely sought after and used offers tend to get snapped up quickly), but it's a very good sounding unit, quite flexible, and a steal for the $.
Good luck with the project.
Bo:
I've thought about Audyssey Pro and looked into buying the calibration pack, but I haven't yet pulled the trigger. Knowing myself, I might get sucked into another year or two of compulsive tweaking and I'm not sure I want to do that. But, either way, thanks for the recommendation. |
Rhyno,
While there's more than a little good info in your recap of JL's white paper, there's also some misinformation - not sure if it's yours or theirs.
Your description of port behavior may get the spirit of the design's performance more or less right, but it's not exactly correct: Ported enclosures are not merely a "trick" resulting from a port tuning phenomenon. A properly tuned ported box will drive the 3db down frequency lower from any given driver/suspension and will roll off faster below that point than the same system rolls off in a sealed box. That's more extended bass - no trick.
Bear in mind that, as you move lower from the tuning frequency, there will eventually be less bass output from the ported box, due to the more rapid roll-off below the tuning frequency. However, if the port tuning is low enough, as it is on many high-end ported subs (I believe most or all of the SVS subs can be tuned below 25hz, for example), that may not be an issue. For music, the rapid roll-off of a ported sub tuned this way will almost never be an issue.
However, there are definitely other trade-offs with a ported box and I personally do agree that it's much easier to get a good sounding set-up with sealed subwoofers than with ported designs.
As to positioning subs in/near the same plane as the mains, many of the external bass management/digital room correction (DRC) systems will delay the electrical signal to either sub or mains to account for the delta in distance between the sub and mains. This allows more flexibility in optimizing position of both the subs and mains, which may be optimized when they are far from the same plane.
I'm not sure whether JL's own system offers this, but I'm guessing that it doesn't. Since JL's products offer in-sub room correction, it shouldn't surprise that they suggest that it's where DRC belongs (and it also explains their recommendation on room positioning). Personally, I use an external bass management DRC system and enjoy the added placement flexibility.
Running the mains full-range may offer the simplest signal path, but it also eliminates one of IMO the biggest benefits a subwoofer offers. All drivers produce more distortion as frequency drops - the longer driver excursions required for lower frequencies will reduce linearity (increase distortion). The good news is that a high quality sub (like your JL which is among the highest quality IMO) is better equipped to handle the heavy lifting at low frequency than is the woofer in virtually all main speaker systems (even including your Magico, I'd think). If you actively low cut the mains, you remove the heavy lifting from their woofer and shift the burden to the subwoofer, where it belongs. Your mains will benefit from the narrower bandwidth they're being asked to handle. So, there's a trade-off; simplicity vs optimizing bandwidth to driver. Some may prefer the full-range option (I definitely don't), but that's a matter of personal preference not system optimization.
Also, you'd need to consider the room-correction side of the issue. If your DRC is in-sub, I assume that it's functional only to the sub's high cut frequency, yes? If so, and you cross the sub out at 60ish hz, you're only room correcting to that point. In every room that I've ever measured, serious response irregularities run up to 120ish hz and significant irregularities persist above 200hz. Below about 80hz, passive treatments become increasingly cumbersome. If you limit your DRC to 60hz and below, there's a lot of room clean-up that you're foregoing.
At the end of the day, I'd say that most of JL's advice (at least as you've characterized it) is sound, but I'd also note that it's definitely slanted in favor of selling their products. |
Lloyd,
The first question in my mind re: actively low cutting your main speaker at 38hz is: What's your program material?
If this is a music-centric system, I'd only point out that very few recordings in my collection have much signal below 38hz. We're talking about a couple of keys on a piano, the longest pipe on an organ, and a couple of notes on the electric bass, for the most part. It's pretty rare that these are present on a recording so the low-cut isn't really doing much to lighten the load on your X-1s 99+% of the time.
Obviously movie soundtracks are another story, but your set-up appears to be 2 channel, so I'm guessing that it's music based. I personally don't see a ton of benefit in crossing a sub in so low on a music system, but many other knowledgeable folks (including, evidently David Wilson) disagree with me on that one.
Rhyno,
I was just trying to clarify a few points that you made in a little different way, because they seemed to me to be presented in the way JL deems best to promote their (admittedly excellent) products. I hope I made clear that I wasn't really taking much issue with the main points in your post, more clarifying in a way that I feel is more even-handed. As you say, however, it's mostly six of one, a half dozen of the other. |
Elegal,
Ideal placement of a subwoofer is most often far from ideal placement of mid/tweeters. If you put a sub in the same cabinet as the other drivers, you'll end up with (pardon the pun) suboptimal placement of one or the other. |
