racedoc,
Main thing to keep in mind is the difference between adding "a subwoofer" and adding several. I've had "a" sub as has Tim and others, and what we're all saying is there's a huge difference when going to the multiple sub/distributed bass array/swarm type setup. Your speakers go pretty deep already, but the value we're talking about is a lot more than that. In other words even if you gained zero in terms of extension and headroom (you will, but assume not for now) then you would still notice a lot of improvement just in terms of the bass being a lot more articulate, musical and lifelike. Its just hard to appreciate until you hear it because listening to only one or two subs in a system that's all you really get, a little more extension, a little more volume. With 4 you open a whole new dimension.
In terms of ambience and soundscape, there's two very different ways people hear or perceive that. There's the higher frequencies where timing is so important and we all pretty well get that part. But the way we perceive and interpret low frequencies is quite different in that timing hardly even matters its the speed and smoothness of the bass that counts. Smoothness comes from more sources that create more modes, which equates to faster bass.
What I'm hearing, or better experiencing because of this, is less like more/deeper bass than more/deeper immersion in the recording. You just feel more "in" the space than in your room.
So to answer your question no, I don't think that "a" subwoofer will do much for you. But three or four? Yes. Definitely. |
“The album was mixed to half-inch analog tape, at the very end of the project to give it warmth. So despite the fact that the first CD’s were issued with a ‘DDD’ marking, it was actually ‘DAD.’ In a blindfold test in Amigo Studio B, Frank Wolf, Jennifer, Henry Lewy, and myself, all chose half-inch analog tape over every digital mix format available that we could test—the Sony 1610, Sony 1630, and a Mitsubishi X-80 2-track digital recorder that used ¼-inch tape.” Italics this time for emphasis. The CD was DAD. The LP was DAA. Also the conventional wisdom would dictate that four speakers spread all over the room wouldn’t "mate" or "synch up" with the mains, or wouldn’t be "phase coherent" or whatever. Instead of what you really get, which is clean, fast, precise, solidly anchored and seamlessly integrated with the mains. And that goes whether run stereo or mono. |
Which yeah Tim sounds about right to me. But however it happens and whatever the explanation the fact is those drums are completely physically anchored in their locations. They never move around the stage even as they change a bit in tone and volume, each whack uniquely its own. There isn’t even a reverberation or anything coming from anywhere but where those drums are. What with the recent tweaks (ECT, Blue Quantum Fuse, PHT, all kinds of HFTs) and now the dba, this sounds so good I went looking to the recording for some sort of reason. Well I haven’t found the drum story yet but what I found is maybe even better: “The album was mixed to half-inch analog tape, at the very end of the project to give it warmth. So despite the fact that the first CD’s were issued with a ‘DDD’ marking, it was actually ‘DAD.’ In a blindfold test in Amigo Studio B, Frank Wolf, Jennifer, Henry Lewy, and myself, all chose half-inch analog tape over every digital mix format available that we could test—the Sony 1610, Sony 1630, and a Mitsubishi X-80 2-track digital recorder that used ¼-inch tape.” Which answers the one question that has been gnawing away for so long, "How the hell did they make such a fabulous recording all digital?" Now we know: they didn’t! The Universe is in balance after all! https://www.mixonline.com/recording/classic-tracks-first-we-take-manhattan-jennifer-warnes-366484 |
Yes what you describe makes perfect sense. Every room has lots of modes, or places where certain frequencies reinforce and make for a lot louder sound. The exact location of these modes changes depending on frequency. But if you play a steady tone and move around you will find lots of places where the tone is much louder (a mode) and much less loud. Depending on the frequency these may be very close together. So in other words its certainly possible for you to feel vibration from a mode on your ankles that doesn't sound like it up where your ears are. Play the same bit with your head down where your ankles were and see.
None of this matter much with bass because we don't get our sense of direction from bass, we get it from much higher frequencies. So like the other night, Jennifer Warnes Bird on a Wire, there's these really awesome drum whacks which even though its mostly very low bass you absolutely here them as being very precisely placed in 3D at several different locations. Each whack sounds individual, each drum stays put in each location. My Swarm is two amps stereo but I tried it one amp mono with the same degree of imaging.
Its like we have two almost completely different hearing pathways or systems, one for low frequencies another more precise for higher. |
rauliruegas
You might want to think a little about that 1% distortion number. Not whether it is true or accurate, but whether it matters. When it comes to really low bass, its hard to see how it matters.
Low bass waves are 30, 40, 50 to even 60 feet long. So long that before the speaker even gets to the end of the first wave the beginning of the wave has already hit and been reflected off the walls many times. But not just reflected. In hitting the walls it moves them, and they move back. This energy in the room from the walls turns out to be one of the toughest to eliminate. About the only thing you can do is build a wall specifically designed to absorb and dissipate this energy, then suspend it over another more structural wall. This is what Geddes does in his room, what some professionally designed studios do. Its not cheap.
But if you don’t do this then you have the walls radiating that energy right back into the room. So no matter how low distortion your speakers, they wind up in that room having five, ten, twenty percent distortion.
That’s just one form of distortion. Standing wave modes and nodes are another, probably even bigger form of distortion.
This is all a part of the bigger picture, which is how speakers interact and work within the listening room. Too often specs are quoted that while accurate turn out to have little or nothing to do with real world performance. |
Tim,
Well I started out thinking save some money but between opting for the second amp, upgraded Morel drivers, and finished in Rosewood mine will probably be about the same all-in as a Swarm with the extra amp. Lotta work. Although, when I told Duke about the Morels he said mine will "kill" his, so maybe worth the trouble after all! lol! As if anyone will ever know. The Distributed Bass Array seems to be the best kept secret in audio, so relatively rare nobody ever gonna compare. Although last time I said that was my turntable, and then Chris Brady actually came over one night so who knows? Maybe Duke finds himself in Seattle some time....!
Anyway between your reviews, Duke's encouragement and the growing excitement of this project coming together I can hardly wait to hear it. Working this weekend but fingers crossed it will reach early hook-up stage next weekend.
Chuck |
Yeah that’s fine Tim I got it covered. Its called room reinforcement. Every room has it to some extent. 3 dB per octave is rule of thumb. But it varies.
The free Parts Express cabs are all sealed. Frequency response of a sealed enclosure drops off very gradually, which actually turns out fine because the drop off is pretty much offset by room reinforcement. But you never can be sure your room reinforcement will kick in just right to match your speaker roll off. They may roll off early. So what Duke suggested, and I of course did, is build 2 sealed and 2 ported.
This way if it turns out I need the extra extension I’ve got it covered with the ported subs. But if it turns out that’s too much then I can simply plug one or two, in effect turning them into sealed cabs with the earlier/slower roll-off.
Some of this I have known since it feels like forever- from having built a transmission line speaker in 1980, and a ported sub about 10 years later. But a lot of the details used here, the use of room reinforcement, the sealed/ported options, and especially the distributed bass array concept itself, for all of that I owe a huge debt of gratitude to Duke. When it gets into "exactly how he does this" its proprietary info but everything else he has been graciously willing to share. As exemplified in his posts here. I only wish more were able to get their minds around this revolutionary development in subwoofer technology.
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plga-
I thought 3D sound came only from the tweeters, but it seems that long bass waves have somehow spatial information that contributes with imagin. Incredible!
While we don't hear low bass frequencies as localized sounds within a sound stage the way we do upper bass, midrange and treble, really low bass does contribute to imaging by imparting a sense of space. Really good low bass like you get with the Swarm or other distributed bass array can put you more fully in the recording venue. This reviewer explains it beautifully. http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/
There is more to what is going on here than just the perception of what is happening in the music itself. There is also a quite startling spatial effect. We are all accustomed to being able to control room effects in the mid and higher frequencies by acoustical treatment. But this is harder to do in the bass, and in most rooms there is a definite residue of spatial signature carried in the lower frequencies. The bass is one of the main ways you sense the size and shape of the room around you, and typically the signature of the recording venue is overlaid or even swamped by the bass signature of the listening room. But the Swarm, presumably because of its smoothing out of response, largely suppresses the bass signature of your listening room. And as a result one can hear the original venue in a most unusual way. I played in a performance of the Sibelius Second Symphony recently, so I was particularly attuned to the acoustic effect this piece makes in a concert hall. Listening to Berglund’s recording for EMI with the Swarm in action, I heard a remarkable facsimile of the size and envelopment of the actual symphonic sound emerge. At the end, I felt like standing up and cheering, so close did I feel at some basic level to the real experience.
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It doesn't take an engineering degree Larry but a little time spent learning a little about each of the areas involved sure does help.
Like, sound travels in waves. The lower the frequency the longer the wave length. This one simple fact seems to cause a lot of problems though because it means sound in a room behaves quite a bit different than most people think. What I mean is most people think it all behaves the same. In fact it behaves very differently depending on frequency. Not only does it behave differently, but we even hear it differently!
Its real easy to get confused by people who don't know what's going on, get their facts wrong, and talk about things like toe in and timing which do matter from midrange on up but do not matter at all at low bass frequencies.
If you want to understand there's great articles already mentioned above by Geddes and O'Toole, and of course everything posted by audiokinesis on here is pure gold. Everything else you should take with a big grain of salt. What is not flat out false is maybe even more dangerous for misleading with a grain of truth. There's also a book I can't recommend enough The Complete Guide to High-End Audio by Robert Harley.
As an example of a little knowledge.... plga has a room 14x28x9 which just that one thing is enough to know he's gonna have problems with a sub. Why? Because 28 is exactly twice 14 and almost exactly three times 9. This means nodes are gonna stack up at 40Hz and 80Hz. Why? Because at 40Hz the wave is 28 feet, at 80 Hz 14, and at 125Hz 9ft, and 125 is almost exactly three times 40. You could literally take a piece of graph paper and map out the nodes and see them.
No wonder plga has had so many problems. He's trying to solve a problem of physics the wrong way, with a sub. The key word being "a".
Now look at noble100. His room at 16x23x8 is almost as bad yet he is really happy with great sota bass! Partly this is because the larger dimensions (16, 23) aren't multiples so troublesome bass nodes are further apart. Mostly though this is because Tim has wisely chosen to solve his bass problem with an actual, bona fide proven to work solution- a distributed bass array.
A little knowledge does indeed go a very long way.
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More audiokinesis gold: And somewhat counter-intuitively, the more subs the easier it is, because the location of any one sub becomes non-critical. Once you've initially positioned the subs, time to adjust the controls. First the gain, then the frequency, then the phase, in that order. Then cycle through a few more times. Don't be surprised if you continue to make fine adjustments, particularly to the gain, over the course of the first few weeks. Duke
That's what I thought but still nice to confirm and clarify: "the more subs the easier it is, because the location of any one sub becomes non-critical." Totally logical once you understand what's going on and the reasoning behind the distributed bass array. It also might be my favorite thing about it. The way my room is laid out it will work out beautifully with one on the front wall left corner, one on the right side wall near the right front corner, another one far back on the right wall, and a fourth somewhere along the left side wall. Should work out great with the existing equipment, in particular a massive turntable rack that definitely is not going anywhere and despite its massive, uh, mass would rather not have a sub sitting right next to it! I got 2 sealed cabs and part of one ported cab screwed and glued together. Man they are heavy even without the drivers! Got the amps in the room, Cones, Shelfs, wire. Depth and clarity or just bass? We're working on it! |
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No worries. Line level comes in, goes to input selector, goes to volume, should be pretty simple to take the volume out and wire it right back to a pair of RCA's on the back. Hard to see that one getting complicated on me. Just never done it before is all.
Already checked, I have enough BDR Cones for everything, speakers and amps, including BDR Shelf for each amp, pure gold (or silver, or both) wire for internal wiring, Synergistic Research Looking Glass Phase II with Active Shielding IC for the amps, more SR speaker cable for two subs, and enough rather ordinary wire for the other two subs including all the internal hookups.
The amps are the same Dayton that Duke uses. Two of em, which depending on how I connect the speakers will be running into either a 4 or 16 ohm load. You're probably thinking of the driver with two voice coils at 2 ohms each that can be wired for 4 ohms for more loading options when several are used. Mine are just straight 8 ohm.
The enclosures I have aren't cut for terminals. I was planning from the beginning on coming in from below and got angled terminals to make that easier. The two that are ported, the enclosures will be enlarged from a cube to a rectangle. Ported requires this both for volume and the extra length needed for the port. Ports will be down-firing so they will still have the clean look of the sealed ones. Just need to make sure the feet/cones on those are high enough to avoid chuffing from air noise if too close to the carpet.
These'll be hooked up soon as possible in plain old MDF. Only after everything is proven to work, then they'll be covered in veneer to match my Talon Khorus. That was my WAF. She also thought it would be nice to match their tapered obelisk look. Was right of course, but I did that on my power line conditioner and all those angles, no way! Got trouble enough finding time for simple pre-cut cubes and rectangles!
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noble100 I was all set to buy the Swarm and almost did. But towards the end of the research phase came across the idea of building my own. At first it was just to use up some MDF taking up space in my shop! Using the first suggested drivers it looked a lot cheaper too. But then I came across this Morel driver https://www.parts-express.com/morel-ultimate-uw-1058-10-subwoofer--297-130 which is a lot better and comes with a free cabinet. While I wanted to use up my MDF the thought of the sawdust alone was enough to jump on this deal. Good thing too, they are now sold out! UPS delivered drivers and cabs, ports, terminals. Pretty impressive looking drivers! Amps aren't exactly lightweights, either. Duke has been kind enough to provide some really valuable insight and encouragement. Frankly everything is available on-line but its still so nice to be able to confirm you are on the right track with someone with experience. So the plan is four subs. Two sealed, two ported. The ported enclosures will be the Denovo freebies expanded out to the larger volume the ported enclosure requires. Parts Express has a page where you plug in some numbers and it spits out some more numbers. I know they are accurate because they're the same as Duke pulled off the top of his head! Lol! Seriously, the guy is that good! Every enclosure however good it is still has its own sonic signature inevitably imparted, unavoidably audible. Splitting the 4 into two shapes helps break that up. My plan is to go even a bit further, using a bit different or thicker material on at least one of them. Got this idea from one of the other DBA builders. Haven't even built them yet but already pulled out the old wire drawer and found power cords and interconnects for the amps, speaker cable, cones... looks like everything should fit. Will need to build something to hold the amps. My main question or problem would seem to be, the sub amps require line level inputs but my integrated has no pre-out. It does however have a couple unused inputs. Figured I would just re-wire internally to connect the volume output to one of the input RCA. Could also hard-wire direct but the internal re-wire will look better, work better, and make changing interconnects a lot easier. Probably not the kind of assistance request you were expecting. Lol! Oh well I'm sure I will be able to figure it out somehow. |
Repeating a bit here but all my experience trying to get really good accurate low bass had me pretty well convinced it was impossible. Yet this experience wasn't all wasted. It resulted in a solid base of understanding from which to evaluate alternative approaches. Because of this, when I happened across Geddes/Swarm/DEBRA it was immediately apparent this held promise. It still took a lot of reading to confirm. Fortunately between threads like this and the articles and reviews it led me to there is no shortage of information out there. Hard to overstate how disappointed I am that so few people are interested. Equally hard to overstate how happy I am that Duke and Tim are interested enough to share and help. Thank you guys. Bigly! On that score, can't help but note that reading about the DEBRA setup Tim uses part way down the page it states, "Conservatively rated by designer Duke LeJeune for 113dB output @20Hz" and
“Room Gain Complementary” tuning (Duke LeJeune)." http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd... So DEBRA or Audiokinesis http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html either way you are getting Duke. Which I was all set to buy, its almost a no-brainer, except I had all these sheets of MDF just taking up space in my shop! Lol! Way back in 1980 an article by Roger Sanders in Speaker Builder explained the challenges of bass reproduction clearly enough to compel me to invest what was for me then not inconsiderable time and money building a set of his transmission lines. With zero personal feedback from anyone having used them. Based entirely on my understanding of the principles. Worked out far better than I ever dreamed. Didn't see it as a leap of faith then. Don't see it that way now. More like a slam-dunk. Thanks to you guys. |
And I totally believe that you are quite capable of hearing when you had the correct phase setting. I just think you are most likely hearing the frequency response improvement that arises from your phase optimization - audiokinesis Hey Duke that is an interesting point you raised there. Reading between the lines you seem to be implying two distinct aspects- timing and frequency response. The way I've been thinking of phase is it sort of emulates location. Like, if the wavelength is 10 feet and you move the speaker 5 feet its the same as 180 degrees in phase. Yet I know that's really simplistic, its not just the one 10 ft wave that was shifted they all are. So is that why the setup (if I even understand that fully!) is first to get the four subs located one by one for flat response, and then fine tune with phase? To minimize messing up timing in the process of trying to get flat response? |
You can lead a horse to water.... |
Today’s post is brought to you by the letter "S".
The letter "S" has the Super Power of being able to turn singular into plural. But not always! Due to a design flaw it can only do this when used at the end of a word. Luddite Forces in the Audioverse exploit this weakness. In a typical mind-trick they say, "This is the subwoofer you are looking for." See what they did there? The original quote was, "These are not the DroidS you’re looking for." They dropped the "S"! Pulling you back, always back, to the singular.
It’s a trap!
Don’t go over to the Dark Side. Unleash the power of the letter "S". Use four subs. |
More Audiokinesis gold: The ear simply does not have the time-domain resolution to hear a slight timing mis-match in the subwoofer region. The ear is UNABLE to even detect the presence of bass energy from less than one full wavelength, compared to which small timing errors are insignificant. What the ear IS very good at, is detecting SPL differences in the bass region. This is implied by the bunching up of equal-loudness curves south of 100 Hz. So the ear can indeed hear something going on as you fine-tune the phase control, but what it’s hearing is the effect on the frequency response. If the main speakers are a bit muddy in the upper bass, you can have the subs overlap them a bit and then use the phase control to dial in some cancellation, thus improving the clarity. I’ve had many customers claim to hear an improvement in clarity from the addition of subs without highpass filtering the mains, and I’ve heard it too, but cannot explain it, apart from the occasional situation described in the preceding paragraph. Of course there is also the improvement in clarity that can come from highpass-filtering the main speakers to reduce cone excursion, in which case the transparency of the highpass filter can be a factor. Regarding adding a sense of depth or sense of envelopment/immersion, if you have two subs, you can place one at either side of the listening position and dial in 90 degrees of phase difference. This will tend to synthesize hall ambience. Credit to David Griesinger for this idea. The 90 degree phase difference ("phase quadrature") will also tend to improve the modal smoothing. Sometimes adding a subwoofer to a tonally well-balanced system tips the spectral balance to the dark side. When that happens, we can bring balance to the force. We can add a rear-firing tweeter to just nudge the spectral balance back to normal, without messing up the imaging by adding another source of first-arrival sound. Duke
More pure gold. I’ve copied the whole post just to pose a pop quiz and see if anyone can answer: what one single letter best differentiates Duke’s highly informative post from all the rest? Hint: to understand the answer is to understand the problem. |
