In high-end 2 channel audio, it seems that the highest subwoofer fidelity would measure ruler flat down to 20hz, and below that hearing threshold accuracy is of minimal concern. Therefore the Perlisten D215s performance here seems phenomenal, am I correct?
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My home office is ~13' x 13'. I've had 3 or 4 subs here:
So I conclude that for larger subs in this room, sealed is the way to go. I've made the same conclusion for passive 2-ways: sealed designs work better, sound better, and excite fewer room notes/sonic anomalies. I also just love the quality of low bass notes from a sealed speaker. There's a punch and truthfullness I just don't hear from ported designs. |
@ghdprentice wrote:
Well then no need to toss around with subs - not even the Sonus Faber iteration, I gather. I'd always go for a pair of subs, but then again I go about it actively and treat the mains + subs as a single speaker system per channel in different boxes, high-passing the mains as well. |
@ghdprentice wrote:
Output and getting it right is really the least of it, I find. I agree many have their sub(s) dialed in too hot, because when they got subs they also want to hear them, and that's when it becomes a nuisance for any serious listening - even with movie playback. Indeed, some home theaters have the subs dialed in ridiculously loud for effect, and to me it just becomes a load of huff and puffing mess that's all over the area. You don't hear that at most cinemas, I might add - at least here they got subs that don't sound as if they're trying that hard. Conversely there can also be the problem of a lack of proper LF-fullness, because a bass reproduction too conspicuous, colored, strained or otherwise will sometimes be negatively gained away so to hide its flaws. If on the other hand a sub sports low distortion (even at high SPL's), plenty of headroom and less of a distinctive mark you can dial back up the gain for more proper fullness and presence in the presentation. Maybe that's why with my previous, low eff. sealed subs that I had to add 4-5dB more gain with movie playback so to have proper impact, whereas with my current, higher efficiency subs I leave the gain where it is and being the same for both music and movies, and it's not for lack of impact and sheer visceral force with movies to be sure, nor the lack of a nuanced, natural and layered presentation with music.
Only 28Hz? Honest extension down to 28Hz is quite deep, and with added room gain they may more closely see into the low 20's. However, it's more about how those lower octaves are being reproduced than extension per se, and for that a pair of subs - properly implemented - may be a blessing to help augment this region more fully. Why not try out those B&W subs you already have, instead implemented with your main music rig, and see how that pans out? If nothing else to get a rudimentary bearing here. |
This much talk about subwoofers can’t help me wonder about how many folks out there are using them correctly. Fortunately there is software to help configure them properly… but, I am surprised how often I have found folks with them turned up way too loud and with the cross overs way too high… doing more damage to the sound than good. Recently, I was over a friend’s house comparing some components. He put on an electronic album with lots of bass… I couldn’t tell anything about the components. I asked about the settings on the subwoofer. It was set to something like 60% volume and a crossover 120 hertz. His speakers were flat to 40hz.
So I had him adjust it while I listened. We ended up with a crossover of 35hz and 20% volume. So both knobs were really close to zero. He was shocked how much better it sounded… the bass wasn’t obscuring the other instruments, the sound field opened up. We listened to the electronic tune… massive single bass notes turned into many… a whole different thing. Home theater is completely different… you want to rattle your windows. But for 2 channel audio it is really easy to do more damage than good and detailed discussions about sub woofer output bring up concerns of over use of subs.
I currently have no subs in my main system, while there are two B&W 800 series subs in our home theater. While I consider putting a couple (Sonus Faber) subs into my system… I am enjoying the complete coherence across the audio spectrum. True, they only go to 28hz… but they sound fantastic. |
@jaytor wrote: "[Open baffle subs] don’t pressurize the room like a conventional sub - the bass is there in the room. For music from traditional instruments like double bass or kick drums, this sounds very natural. These instruments don’t pressurize the room either. "But if you are looking for that kick-in-the-chest sound, this type of sub is probably not for you." Imo the advantage of an open-baffle, dipole sub is better room-interaction than monopole (omnidirectional) subs, resulting in smoother in-room bass. And smooth bass is "fast" bass, perceptually, because it is the in-room peaks which take longer to decay into inaudibility and therefore muddy up the bass. The result includes superb pitch definition in the bass region. But one trade-off is, good dipole bass doesn’t kick you in the chest like good monopole bass does. I say this as a long-time dealer for dipole speakers (SoundLabs). Imo there is a technique which can combine in-room bass smoothness with kick-in-the-chest sound, and that is to use multiple monopole subs intelligently distributed. As the number of distributed bass sources increases, the in-room frequency response smoothness increases, and the variation in that frequency response from one location to another within the room decreases. Disclaimer: I manufacture a distributed multisub system, BUT the concept can be implemented just by using multiple subs and spreading them around the room, and the subs do not have to match. Imo the room’s effects in the bass region are roughly an order of magnitude more significant than the differences between comparably high-quality subs, so arguably HOW MANY subs you use (and how you use them) can matter more than WHICH sub(s) you use. Duke |
@jaytor -- It would be interesting to experiment with a pair of open baffle subs in a 2nd listening space and setup - they seem like a very capable design, not least as an overkill i.e.: über-sized option. 180Hz low-pass should be plenty enough to allow for a variety of design options above, like Danley’s Synergy horns or, like in your case, a line source. Come to think it I listened to a pair of Quad ESL 63’s augmented I believe with a pair of open baffle fitted-to-the-Quad’s Gradient subs (dual 12" Peerless woofer per cab) back in the 90’s, and it was the best I ever heard the Quad’s. Indeed the pairing with the Gradient OB subs was excellent, and going by memory I’d favor that combo over the newer, more full range Quad iterations. The TH’s are great for both music and movies, so yes, perhaps an OB solution wouldn’t offer the same versatile abilities here. Nonetheless they sound like an intriguing option. |
@phusis - I am currently crossing them over at around 180Hz. My main speakers are dipole line arrays which start to roll off around 200Hz, so this crossover point blends well. The sub towers with the plate amps I'm using won't play much higher than this. The drivers are made by Rythmik for GR-Research, using a paper cone specifically optimized for open baffle. Each tower is driven with a Rythmik plate amp (HX800) which is built using two Hypex 400w amps, so the plate amp actually has two channels of output, each of which is connected to two drivers. These drivers have a second voice coil which is used as a servo feedback circuit to the amps. I don't think I've heard a tapped horn sub, but from your description I suspect the OB subs sound somewhat similar. They don't pressurize the room like a conventional sub - the bass is there in the room. For music from traditional instruments like double bass or kick drums, this sounds very natural. These instruments don't pressurize the room either. But if you are looking for that kick-in-the-chest sound, this type of sub is probably not for you. I wouldn't use them for home theater, for example, since most of the bass is from sound effects like explosions which you do want to pressurize the room.
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@jaytor wrote:
Your open baffle bass/subs approach is an interesting alternative. I’ve heard a range of open baffle main speakers and generally liked them, but have never truly considered open baffle as a bass/subs tower option only. How high are you crossing them to the mains - indeed, how high can they be crossed? Going by your descriptions they seem to share at least some characteristics of horn-loaded sub variants. Myself I’m using a pair of tapped horn subs (a Tom Danley patented design, though DIY’ers are allowed to roam freely making their own versions), fitted with 15" B&C pro woofers and tuned at approximately 23Hz. With a 20 cf. volume per enclosure they’re some bulky critters, but that’s the price when you need fairly deep extension in addition to higher sensitivity (97dB). They’re high-passed @20Hz (36dB/octave BW) because of the unloading of the woofer below tune, if mostly to alleviate any added distortion here. Anyhow, few realize the smooth, effortless and immersive bass TH’s can produce, because hardly anyone have heard them in a home environment. It’s difficult to describe, but the bass of TH’s is just there in the room as this immersive presence; you don’t sense the bass being produced by cones with any effort, and as such it’s actually a rather "civil" though visceral bass reproduction compared to direct radiators (be they ported or not), that by comparison - to my ears - draw more attention to themselves. It would seem though in your case with the open baffle subs that they’re not a typical representative of direct radiators. Some 5-6 years back I used a sealed 16" sub (SVS) and later added a 2nd one on loan to see how that panned out. Two of them no doubt was the preferable solution, but after quite some experimentation I still couldn’t them to gel in a satisfying manner with my then all-horn main speakers, and so I scrapped them both and went with the TH’s instead. To say it made a difference is an understatement. The SVS’s went slightly deeper (infrasonic territory) and had a nice clean punch, but compared to the TH’s they simply felt compressed with bad layering, while lacking in central bass agility or "aliveness." The TH’s have a smoother, fuller, and slightly warmer imprinting with zero overhang - something that, conversely, marred the SVS’s - not to mention that the TH’s can be downright scary in their visceral-dynamic prowess and SPL capacity, and even so the B&C woofers barely move. If given only the choice of sealed vs. ported, I’d go with a pair of large, higher efficiency ported subs (say, dual 18" or single 21" per cab) with a relatively low tune. Or, 21"-loaded 6th order bandpass designs with prodigious port area on one side of the cone, and short horn-loading on the other. |
The choice between sealed and ported subwoofers depends on your specific audio preferences and the intended use of the subwoofer. Both types have their own advantages and drawbacks. Sealed Subwoofers:
Ported Subwoofers:
Ultimately, the choice between sealed and ported subwoofers depends on your priorities. If you primarily listen to music and value accuracy and tightness, a sealed subwoofer may be your best choice. If you are focused on home theater or want more output for a larger space, a ported subwoofer may be more appropriate. Keep in mind that there are hybrid designs and advanced technologies that aim to combine the best of both worlds, providing accurate and deep bass with high output, so it's worth exploring those options as well. Additionally, room acoustics, placement, and personal preferences will also influence the performance of your subwoofer, so experimentation and careful setup can be essential for achieving the desired sound quality. |
Porting main speakers is a much different proposition than subwoofers with ported enclosures. Biggest reason is the x-max is much less (distance a driver piston is allowed to travel) on main speakers and is easier to to control the motion with the driver's suspension. Lack of control of driver excursion whether main woofer or subwoofer causes distortion. Most main speakers are ported because they are more efficient and extend deeper and the slight additional distortion is a worthwhile tradeoff and not audible. The main reason I prefer sealed subwoofers for music is that they have significantly less distortion than their ported counterparts, especially where it matters most in the critical 25 to 80 Hz region. That distortion can cause coloration that can veil the midrange frequencies- not good if you love vocals and clarity. Ported subs work well for home theater because the additional distortion is not so noticeable in a typical effects sound track and the additional efficiency and extension is more useable. Also midrange clarity is not very high on the list of home theater system users. Again, distortion at critical audible frequencies that can veil the midrange with ported subs is the main reason to avoid them for music. |
Another option to consider is open baffle, if you have the room. I am really enjoying the bass from my open baffle subs, and prefer the bass quality compared to the sealed and ported subs I have had in the past. To me, it sounds much more natural than box subs - smooth, clean and dynamic, without pressurizing the room and without the boxy resonances that many box subs have. Open baffle subs have cancellation on the sides of the speaker, so fewer room modes are excited resulting in smoother in-room response. Also, since they don't pressurize the room, less bass energy escapes the room. The downside is that the drivers have to work harder to compensate for the cancellation between the front and back wave. If you like to play loud and/or have a large space, you'll need multiple drivers to play deep. They also have to be placed at least 3 feet from the front wall (although they can be very close to the side walls). I use a stereo pair, each with four 12" drivers in a tower configuration. This is overkill, but results in lower distortion and smoother response. I've heard it stated that you can't get deep bass from an open baffle woofer. This just isn't the case. With Room EQ Wizard and a little bit of PEQ adjustment on the sub amps, I've measured flat response (within a couple DB) to below 20Hz, with the -3db point in the mid-teens. They can easily play WAY louder than I'd every want to play them.
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@tvrgeek wrote: "For music, I much prefer low Q sealed. The roll-off much better matches the room gain so flatter to start with..." @erik_squires responded: "This is a subject I don't think most audiophiles understand. You have no idea what in-room bass response will be until you get the speaker in place. In many cases the problem is too much bass and exaggerated room modes." A couple of different researchers, Martin Colloms and Dan Wiggins, have written to the effect that "typical" room gain from boundary reinforcement is about 3 dB per octave across the bottom couple of octaves. Now obviously this is going vary significantly from one room to the next, as well as with speaker and/or listener position within a given room, and this general bass-boosting trend does not predict the inevitable room-induced peaks and dips within the bass region. But the general trend is that rooms introduce some rise in frequency response in the bass region In general rooms tend to boost the low end by less than the typical rolloff of a sealed box system, which is often given as 12 dB per octave, although a very low-Q sealed box can have an effective rolloff closer to 6 dB per octave. Therefore very low-Q sealed box systems often synergize quite well with the room, as long as their rolloff doesn't start too high. On the other hand vented boxes are usually tuned to remain "flat" down to a considerably lower frequency than a comparable sealed box, rolling off rapidly below the port tuning frequency. This inherent response PLUS room gain can result in the "too much bass and exaggerated room modes" Eric mentions. Going back to our hypothetical "typical" room gain of 3 dB per octave in the bass region, it's really not feasible to build a sealed box with a Q low enough that its inherent rolloff is the approximate inverse of this room gain. However it IS possible to build a vented box whose inherent response slopes downward by about 3 dB per octave across the bass region, accelerating to 4th order (24 dB per octave) rolloff below the port tuning frequency. If the port tuning frequency is sufficiently low (say 20 Hz ballpark), then the system's inherent response starts outs "in the ballpark" as far as synergy with room gain goes. So while I agree that in general sealed boxes interact with the room better than vented boxes, imo there is a type of vented box tuning that can usually interact with the room even better than an unequalized sealed box. My marketing department calls it "room gain compensation" tuning. Duke vented box subwoofer manufacturer |
This is a subject I don't think most audiophiles understand. You have no idea what in-room bass response will be until you get the speaker in place. In many cases the problem is too much bass and exaggerrated room modes.
Well, a subsonic filter can protect your speakers and reduce power demand, but sure.
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For music, I much prefer low Q sealed. The roll-off much better matches the room gain so flatter to start with, and you don't need additional subsonic high pass filtering. Less group delay but I don't think that is really very important. If you are using DSP eq ( I suggest you do), the cabinet alignment may not be as critical. I like to start close and just hit the modes, so not giving up on sealed. I run the DSpeaker box in line with the sub only on my stereo. HT is of course done by the AVR. A passive radiator is a PORTED enclosure with the advantage of no port chuffing. The PR needs to be at least twice the area of the woofer to work correctly. Many are not. Very handy when the port calculations wind up with 8 foot ports. Down side is cost. For movie special effects where I want that crazy 20 Hz rumble, OK, I can see ported. That said, my HT is a pair of 10 inch sealed, Q .65 in push-pull and they can shake the house. F3 is around 30 Hz, so with room gain, they are almost flat @ 20. My stereo is a single 12 inch critical Q (.5). It does way more than I could ever use in my large open space living room for music. I don't do heavy organ or computer synthesized stuff. If I can feel tympany in my chest, that is enough. Both systems are powered by a simple O-Audio BASH plate. No mega power needed. I know 1000W or so is popular, but you don't actually use it. Do the math. I can do 95 dB with less than 1% THD with either system. The HT does 102 dB before XMax @ 20 Hz. Not mentioned are infinite baffle. They have quite a following. A DIY only. Finding a driver to work is not easy. I played with them briefly but found no real advantage. "Tight" "Accurate" "Dynamic" Marketing BS. It is the execution, driver, and crossover. Or people repeating you-tube reviewers who have never designed speakers making up crap to fill a video. Any cabinet and speaker can be much, or sharp as a tack. The one absolute truth is: Listen for yourself in your room.
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Sealed and ported have similar efficiencies in the pass-band. Ported will go down lower. All my experience and measurements say that the bigger issue is the amount of bass in a room. If you want to plumb the depths of bass with a sub you have to be careful of the placement and use appropriate room treatments and/or EQ as/if needed. Smaller, sealed subs tend to leave the sleeping dragons alone. They don’t excite the room modes and therefore won’t ruin the sound. It is also true that below the tuning frequency, ported subs climb in distortion due to increasing exertion. They may also be significantly larger than the sealed counter parts. I use a Hsu sub which has optional plugs. Whether I use them or not has to do with the in-room response. Having said all of that, if we aren't talking about subs, I built a sealed center channel specifically because I knew I wanted to use it with a subwoofer, and crossing it over at 80 Hz or so would mean I'd get a lot of dynamic range and lower distortion in that configuration than I would otherwise. |
Sure. Porting a woofer or subwoofer is a way of pushing the speaker down lower flat. The problem is they roll off quickly below that. Sealed subs and woofers are less efficient, start rolling off earlier, but continue on down lower than ported speakers. Ports can make noise. Sealed subs can play just as loud but require more power to do it. Since they go lower you can use DSP and a lot of power to produce very low frequencies. I make subwoofers and will only make sealed ones. I I use 2500 watts per sub with digital signal processing to align the subs with the main speakers. |
