17 of 23 speakers in my studio and home theater systems are internally powered. My studio system is all Genelec and sounds very accurate. I know the best new concert and studio speakers are internally powered there are great technical reasons to design a speaker and an amp synergistically, this concept is much more important to sound quality than the vibration systems we often buy. How can an audiophile justify a vibration system of any sort with this in mind.
@mijostynVery good points, especially about the AES inputs, I'll look into that.
So I finally got everything working with my Genelec (analog speaker inputs) system and I was very happy even though the speakers have not been time aligned, I was playing test tracks and different surround sound formats for about 6 hours. Then I listened to my 2.2 system and there was no comparison the 2.2 was so much better, I mean better in a way that was not more accurate but better in a way that was nice to listen to and magical. Subs make all the difference I was very unhappy with my Paradigm 9hs until I bought the separate subs. The 9hs do have balanced Sub drivers but somehow on mine they were very unimpressive even with an adequate 700W amp in each cabinet. The external subs have a 3kW amp and shake the house that's important good base needs to be felt, I spent another 15k on nearly 40k speakers to get the bass right I'm so glad I did.
I think subs can be used in a square cabinet because the length of the frequencies are so long there will be no interference internally. Of course there are the old formulas that are ratios of speaker volume SPL of Frequency and volume the smaller the box the more power you need.
@donavabdear, I was thinking about getting the new Jim Fosgate designed tube headphone amp The Aries from Black Ice audio which was demoed at this past CEDIA. They don’t have a price yet or a firm release date. I really like my Sony SACD/CD/Blueray player and wanted to try out their reference Signature line. I will likely get the matching headphones after I try it out as a DAC and a preamp. The DAC is a custom field programmable gate array and should be quite interesting vs the ESS and AKM DAC’s out there. This is why it has some of the features you don’t see on most DAC’s like the DSD remastering and higher bit rates on PCM:
DSD native (up to 22.4 MHz) DSD DoP (up to 11.2 MHz) PCM (up to 768 kHz/32 bit)
The fact that it has headphones designed to match the amp was a plus.
@donavabdear , My system is really very simple. I have a digital preamp that takes digital inputs from a universal disc player, the TV box and a Lynx Hilo. Connected to the Hilo is my phono stage, an Apple Mini, the Apple TV box and the Sonos connect. The Connect is hooked up to a very powerful router along with the Apple TV box. All the processing is done in digital. The processor is managed by a PC not the Apple mini which just plays music from a 6 TB hard drive. The processor has 4 DAC channels that power two speaker amps and two sub amps. The Hilo is a studio ADC/DAC mixer of amazing capability. There is nothing on the consumer market like it. As soon as it is released I will be getting a DEQX Pre 8, a full digital preamp with Room control, EQ and a 4 way crossover. It have 8 DAC channels. I may add ribbon tweeters to my ESLs.
As far as subwoofer enclosures are concerned a square or rectangular box is the worst design. The air within the enclosure is a spring. In the old days this was called acoustic suspension and like any suspension it has a resonance point. There are no standing waves within the enclosure. The enclosure wants to expand and collapse. Each size panel now has it's own resonance point as they flex and that resonance point can be up in the midrange! Put your hand on the enclosure while the sub is handling heavy bass 30 Hz at 90 dB. First put your hand on a corner. The vibration you feel there is the enclosure moving back and forth from the Newtonian forces generated by the driver. Next put your hand in the middle of one of the sides. Here you feel a combination of the enclosure moving back and forth along with it expanding and contracting. A cylindrical enclosure is inherently stiffer and will be very resistant to compression and expansion. It will still move back and forth to Newtonian forces unless you mount an identical driver on the opposite side and drive it in phase with the front driver. This is called a balanced force design. You would have to double the enclosure volume resulting in a larger subwoofer but with the right modern subwoofer drivers you could still limit the size to 2 cubic feet excluding the volume of the drivers about another cubic foot. 3 cubic feet is not horrendously large.
@kota1, the absolute best place for a sub woofer is on the floor in a corner. The next best place is on the floor against a wall. You are sort of horn loading the sub. The only problem is time alignment which can be easily taken care of digitally. You can see the group delay with a good measurement system but in order to correct it you need DSP.
Hence bracing, The large the panel dimensions, the greater the bracing. A superior shape is of little benefit if we cannot manufacture it, added shipping costs ameliorate the benefit, or it causes difficult in use for the customer. FEA allows easy and quick analysis of designs.
I thought the trunk was the bast place for a subwoofer.
the absolute best place for a sub woofer is on the floor in a corner. The next best place is on the floor against a wall. You are sort of horn loading the sub. The only problem is time alignment which can be easily taken care of digitally. You can see the group delay with a good measurement system but in order to correct it you need DSP.
Hence bracing, The large the panel dimensions, the greater the bracing. A superior shape is of little benefit if we cannot manufacture it, added shipping costs ameliorate the benefit, or it causes difficult in use for the customer. ...
Hence DIY; in principle every design, shape and size (and weight) can be pursued. I’ve gone the horn route with subs where the horn "innards" are elaborate bracings. Large behemoths, but constructed in 13-ply BB with CNC-cut and interlocked panels they’re very sturdy. Further damping can be applied and accommodated as one deems necessary.
Distortion isn’t only cabinet vibrations but as well mechanically induced noise from the direct radiating and exposed woofer(s) during high excursions. Horn-loaded woofer cones, while concealed inside the horn, move very little for a given SPL, potentially both due to high efficiency and the way the woofer cone can have minimum excursion at the tune (via Tapped Horns; not the more traditional Front Loaded Horns where the woofer is usually placed in a sealed chamber). Avoiding mechanically induced noise here is not trivial.
Very few audiophiles have been "exposed" to the sound of horn-loaded subs (or their variants), not least for the reasons you outline as a MFR, which is a shame, because they deliver a very smooth, enveloping and effortless bass reproduction when carefully implemented - certainly audiophile qualities in bass reproduction to aspire to. Their ability to produce truly prodigious SPL’s is part of their perceived prowess here (and so not only about loudness per se), because significant headroom equates into cleaner/less distorted and more relaxed bass.
@mijostynre: sub setup I set mine up per Earl Geddes. He actually recommends at least 3 and to have one above the midline level of the room if possible, see pg. 236. I only have two and use the opposing corner setup:
@phusis, the main issue is that most of my customers are not willing to expand the size of the control / mixing / listening rooms to accommodate the required size of a horn subwoofer in order to get a sufficient efficiency boost at the frequencies the subwoofer is expected to cover. Even for a subwoofer I need to be careful about dispersion as well.
@thespeakerdude, I do not care if you can produce a complicated enclosure or not. I am not limited by financial and space confines. I can build whatever I want. That is the beauty of DIY. If you have the tooling, you can make just about anything. I already have a technique for building cylindrical enclosures and the beauty of it is that the wall thickness varies continuously repetitively between two inches and 1.5 inches 10 times.
@phusis, that is absolutely correct. The smaller the excursion the lower the distortion. It is why bigger drivers have less distortion than smaller ones. The problem with horn loading is size and the difficulty building a large dampened enclosure. The alternative is using multiple drivers. Every time you double the number of drivers you increase efficiency by 3 dB which requires 1/2 the excursion. In a 16 X 30 foot room 8 12" drivers in corners and against the front wall will do admirably.
@kota1, Earl is trying to do the distributed bass gig in his own way. Drivers against a wall on the floor are 3 dB more efficient than drivers not against a wall. Drivers in corners are 6 dB more efficient. More efficient drivers = less distortion. It is also important for the drivers to be less than 1/2 the wavelength at the crossover point apart. Say you want to crossover at 100 Hz. That wavelength is about 10 feet. You do not want your subs more than 5 feet apart. Within 5 feet they are acoustically operating as one driver. If you look at my system page, the front wall is 16 feet. The subwoofers are 4 feet apart forming an infinite line source. This makes them even more efficient and sonically more powerful.
@mijostyn, thanks. I EQ them with Audyssey in my processor. I have a question for you. I run two subs because my processor has two sub outs. I would still like to add a third one as Earl describes. I am thinking of getting a DSPeaker or miniDSP to EQ them. Should I skip it and just stay with two? I don't need more volume and the bass is satisfying. I am just wondering if it would be OTT good if I add another one. Thanks
@thespeakerdude, you can see how my subs measure without room correction in the graph below (blue frame is before), thoughts? The numbers in the scale are cut off when I uploaded it from PDF.
@kota1, You do not want to add another processor. The best way to do it is add 2 subs, one to each channel and stay with a 2.2 system which is what I do, two subs per channel. Remember the main speakers are equal volume at the crossover point and can be included in the distance factor but if you have a point source system the subs of each channel should be right together but the channels separated by 1/2 the wavelength of the crossover point. You could also put them way apart like some people do with a distributed sub system. My own preference is to put all the subs on the front wall, but I also cross at 100 Hz.
You need to include Hz on the horizontal axis and dB on the vertical. We are need points of reference. Change the size of the file to fit. The subwoofer files are typical. You see the room Modes. Room control is a beautiful thing.
That sounds right, I am going to shelve any tinkering with more processors, etc. I think I’ll go in the opposite direction and try 2.0 with no subs and no dsp when I get the new Sony preamp delivered and will post how it goes. The Paradigm passive 40's go down to 45 hz or so. The active version I use go down to 32 hz which should be fine for music.
They may go down to 32Hz, but that is probably with drop-off and high distortion, and if using 2, more room mode excitation. Subs are to reduce distortion, go deep without roll-off, and reduce room mode excitation. Ideally you cross your speakers higher so they are not taxed with frequencies/excursions where they distort.
@thespeakerdude, the active 40's have a high pass filter switch on the back so I can cross them over with a sub, NP. I'll try both and see how it goes, thanks.
@kota1There are very few speakers that do anything gracefully below 50 Hz. The specs are highly misleading. Standard frequency response measurements are taken at one meter. That is fine for wavelengths one meter or less. The longer wavelengths dissipate rapidly with distance in a room and the longer they get the more rapidly this occurs so by the time you get to the listening position a speaker that measured flat to 40 Hz is now down 10 dB at 40 Hz and depending on the room and interference patterns it could be down 20 dB in some places. Then you get some places in the 50 to 100 Hz area that might be + 10 dB producing what I call one note bass. Producing accurate bass requires clever room management, a subwoofer with a lot of power and room control. Why is the sub necessary? Simple, if you try to correct a regular woofer to run flat down to 18 Hz in most rooms you will either run out of power and clip your amp or break your woofer trying to get long excursions out of it that it can not handle. Subwoofer drivers are designed specifically to take long excursions and handle lots of power. They have ported and vented magnet structures so that there is no compression behind the voice coil and spider. The spider is the suspension element that centers and controls the voice coil and the apex of the cone. Another thing is, for a large high fidelity system do not bother with subwoofer drivers less than 12" unless you plan on using them in multitude. I would use no less than 4 10" drivers, or two 12" and up. The more driver area you have going the better. I would not use anything larger than 15" as I think the larger cones are more difficult to control. I have seen slo-mo videos of large cones wobbling instead of moving in pistonic fashion. The "speed" of a driver determines it's frequency response. The larger driver will not have to move as fast to produce a specific frequency because it does not have to move as far. Smaller drivers have to move faster! Larger drivers produce less distortion because they do not have to move as far as fast. They are thus capable of generation much more acoustic energy the result being you "feel" as if you are at a live show. Feeling the music is almost as important as hearing it. It is the feeling that is missing in most systems which IMHO ruins the illusion.
They may go down to 32Hz, but that is probably with drop-off and high distortion, and if using 2, more room mode excitation. Subs are to reduce distortion, go deep without roll-off, and reduce room mode excitation. Ideally you cross your speakers higher so they are not taxed with frequencies/excursions where they distort.
I would not use anything larger than 15" as I think the larger cones are more difficult to control. I have seen slo-mo videos of large cones wobbling instead of moving in pistonic fashion. ...
Some of the high order bandpass designs I’m considering that are equipped with high efficiency, pro 21" neodymium magnet-fitted woofers (crazy powerful, extremely sturdy drivers) wouldn’t see problems with cone wobbling in any domestic setting, let alone in pairs or - God forbid - more. Both the output generated by the front- and back wave of the driver is utilized, and with high eff. to boot cone movement will be kept to a minimum - even at quite staggering SPL’s. These are tuned to offer "no more" than 25Hz honest extension, however (20-ish Hz in-room, plenty for me); if crawling well below 20Hz is needed, not to mention below 15Hz, a steep rise in cone movement is the result, as well as effective enclosure volume to maintain visceral impact. The 15" woofers in my tapped horn subs (also a high eff., high-order bandpass design, tuned just below 25Hz) move only a few mm’s at most at bonkers SPL’s that are viscerally felt. That’s making the most of a given cone area in a design that’s a force multiplier.
@phusis, let me change that to I’m overthinking. I have a well treated room that is nicely EQ’ed in my main system which does everything from 2 CH to 9.2.7 Atmos. I just got a new preamp/dac/headphone amp in the Sony Signature line. I can connect it via RCA to my HT processor and use the subs, the EQ, etc. I can also connect it via balanced directly to my active speakers. Too systems, totally different, in one room. Before I start messing with subs and EQ with the new 2 CH pre I want to let it go and see what happens. Paul McGowan disavows EQ in a 2 CH system (but still likes subs).
I got the new Sony Signature TA-Z1HES installed tonight and so far have only used it as a dac connected to my main system (subs, EQ, etc). I connected it to a laptop and streamed some ripped files as well as streamed tidal. I must have a bias to Japanese tuned products because my processor is a Marantz, this new unit is a Sony and my DAP is an Onkyo DP-X1. The dac in the Sony is crystal clear straight out of the box, I look forward to breaking it in. Of the upsampling features I like DSD remastering the best. You can only engage it with files of CD resolution or lower (44hz). The real surprise was when I let my Onkyo DP-X1 DAP upsample and output the files as native DSD. I have the song Angela by Bob James on an SACD and heard it many times. I never thought upsampling could approach native DSD and if I didn’t know it I couldn’t tell the difference. When streaming Tidal I have to let the DAC do the DSD remastering. The DSD choices available are limited, inconvenient, and expensive. What a pleasant surprise and I would say just as a dac this unit justifies the price. I’ll try it as a two channel preamp tomorrow and post. The engineers at Sony know digital.
@phusis, The problem most of us face with subwoofers with normally sized rooms in a residential setting is SIZE. Horn loaded subwoofers would have to be huge to work correctly. Same thing goes for the enclosures required to house a 21" subwoofer. It is much easier and more cosmetically acceptable for most people, myself included, to use multiple smaller drivers is sealed enclosures. With modern drivers you can get a 12" driver into a 1.5 cubic foot sealed enclosure and with enough power and digital signal processing you can get it to do just about anything within the limits of your amplifier to work perfectly. I use 8 of them which equals 4 15" drivers or two 18" drivers. In a 16 foot wide room I have no trouble getting flat down to 18Hz where they are rolled of steeply by a digital high pass filter at 84 dB/oct so as not to waste power and piss of the turntable. They are actually boosted 6 dB or so at 20 Hz to simulate the visceral sensation you get at a live concert at more reasonable levels. They are also in perfect phase and time with the main speakers. This is critical if you cross over at 100 Hz like I do and don't want to know you are listening to subwoofers.
I used to work for a church doing sound that had the biggest electronic organ in the world. There were 4x 30 inch subs in separate cabinets on both the left and right sides of the main sanctuary the cabinets were not facing the same direction. The organ sounded wonderful and could keep up with the biggest real organs in the world. The speakers for the organ were not set up like a concert but looked like someone had randomly designed them, definitely more of an art than science.
My room is wonderful because it's fairly large and is not square or rectangle and doesn't have any flat parallel walls it has a 10 foot ceiling. Just last night I moved my expensive Lyngdorf 60-2 processor to my Dolby Atmos mixing system simply for it's acoustic room fixing system "Room Perfect", until now I didn't have to use any acoustic processing it simply didn't help even with powdered subs built into my main speakers and 6k watt separate subs next to the speakers. I nearly bought very expensive speakers but realized I only need very good high and mid frequencies and the low frequencies if done right will make everything smooth out. Low frequency is an art, ears are the most part of tuning the system, play a 60hz or 80hz tone and roll the phasing where it's most pleasing musically. Don't forget any latency if you have any digital devices you have latency no way around it.
My Atmos system speakers distances are not spec, newer thinking in acoustics is tending toward non symmetrical speaker placement I fully agree. Ultimately a mixing room needs above all to be standard but this room is personal and I want to experiment, a lot. In the future even 2 channel speakers will be object based and won't need to be symmetrically based.
Also, about diminishing returns when it comes to low frequency. The best system I ever heard was at Harmon headquarters in LA when I was doing playback for a music video and the location person who was an employee of Harmon showed me there big concert system inside the room we were doing the music video in, it took a few minuets to set up but wow I didn’t expect huge speakers could sound so good. There was so much physical movement of low frequency sound that it stunned me. It wasn’t amplitude volume it felt like thunder that even at low amplitude you can feel how huge it was. Bigger is better, this Harmon (JBL etc. ) was a demo to show big concert companies how good sound can be if you want to pay for it and it was amazing. Of course all powered speakers.
Very few audiophiles have been "exposed" to the sound of horn-loaded subs (or their variants), not least for the reasons you outline as a MFR, which is a shame, because they deliver a very smooth, enveloping and effortless bass reproduction when carefully implemented - certainly audiophile qualities in bass reproduction to aspire to. Their ability to produce truly prodigious SPL’s is part of their perceived prowess here (and so not only about loudness per se), because significant headroom equates into cleaner/less distorted and more relaxed bass.
I too am running bass horns - front loaded folded bass horns loaded in the corners of the room, with four 18" drivers on each side. My friend designed and built these with me as his shop assistant and employer. There really is something to the effortlessness of that bass. My non audiophile friends have commented on the bass and that alone. They weren’t impressed with the horn mid and high frequency reproduction, and I think for good reason. Even the best direct radiator bass has a sound of grippy force and power, like something is working hard. One reviewer called it "Iron fisted" bass. I know what that is and it’s impressive in it’s own right. Horn loaded bass doesn’t require nearly as much power to produce plenty of volume and it comes across somehow as sublime. At a quite loud 30Hz those drivers are barely moving.
I heard a lot of good stuff at the Pacific Audiofest this year but I didn’t hear any great bass. Some of it was fairly good though.
At the present moment I’m in the process of moving in to a new place and it will be a while before I can get the bass horns back in action. for now I’m listening with 2 10" conventional subwoofers. They’re way better than not having them and it’s enjoyable - but nowhere near the same. Obviously it would be closer if I had 8 of them in the room stacked in the corners instead of just 2 and they were all 18" instead of 10", so yeah, not a fair comparison. But I think the point is cone excursion matters. The bass horns only had 160 watts total power distributed between the 8 drivers. More than enough - most of that was used to push them a bit lower than they want to go because of limited back chamber volume.
@phusis , The problem most of us face with subwoofers with normally sized rooms in a residential setting is SIZE. Horn loaded subwoofers would have to be huge to work correctly. Same thing goes for the enclosures required to house a 21" subwoofer. It is much easier and more cosmetically acceptable for most people, myself included, to use multiple smaller drivers is sealed enclosures.
The issue usually is not whether large subs can physically fit into and function properly in residential spaces, but whether one chooses and wills their inclusion. You mention what’s "cosmetically acceptable" to most, and that’s absolutely correct; most don’t want such behemoths in their listening room, let alone shared living ditto. Speaking for myself though with a dedicated space I don’t care about convenience (setting them up) or what’s aesthetically pleasing or not, but just plain and simple functionality - unapologetically. Btw., 1/4 wave horn sub iterations have their size pretty much laid out dictated by the parameters sought, and properly designed as such work wonderfully.
It’s about what works, what is required and the benchmark one sets out to work from. To me what’s no larger than ~20cf. per cab is acceptable and physically doable, and ultimately it pays off with regard to headroom and ease of reproduction.
With modern drivers you can get a 12" driver into a 1.5 cubic foot sealed enclosure and with enough power and digital signal processing you can get it to do just about anything within the limits of your amplifier to work perfectly. I use 8 of them which equals 4 15" drivers or two 18" drivers.
Many ways to skin your cat, sure. Multiple 12"-fitted sealed subs like in your case can be a very effective solution, but I think we can agree on that 4 such subs and the weight class they represent would be more than what many audiophiles dare to embark on. It goes to show that if sufficient pressurization, extension and some measure of headroom is the goal there’s no way around physics and (at least an proximation to) ample displacement.
Where I differ is the want for more efficiency and less excursion (for a given SPL), and that requires even more size, so much so - even with way larger cabs - that it comes at the cost of ultimate extension, unless one sets out to work with ginormous horn subs. What’s the summed volume of your 4 sub cabs, ~15cf.? My two TH subs come in at 40cf. (tuned to just below 25Hz), and yet your solution has the lower knee - at the cost of efficiency, the need for more power and added excursion, of course.
Just as an example what high eff. means power-wise: the blue signal LED’s on my MC² Audio amps (1 for TH subs and 1 for EV bass bin) only flash up when reaching 10W, and even at ref. volume watching movies they remain off. I have to seriously crank it for the LED’s to come to life, and there’s +600W disposable to the subs alone..
In a 16 foot wide room I have no trouble getting flat down to 18Hz where they are rolled of steeply by a digital high pass filter at 84 dB/oct so as not to waste power and piss of the turntable. They are actually boosted 6 dB or so at 20 Hz to simulate the visceral sensation you get at a live concert at more reasonable levels. They are also in perfect phase and time with the main speakers. This is critical if you cross over at 100 Hz like I do and don’t want to know you are listening to subwoofers.
Implementation is key - never doubted you have that well covered, as is obviously the case. I cross just below 85Hz to the subs, and the whole speaker setup incl. subs is treated like a 3-way system, and not just with the subs added on as a secondary implementation/thought without high-passing the mains and other. The subs are high-passed @20Hz - theoretically to protect the drivers, but practically to lower distortion and keep them from working in a frequency range where the design wouldn’t do any good anyway - and filter steepness throughout is 36dB/octave.
I too am running bass horns - front loaded folded bass horns loaded in the corners of the room, with four 18" drivers on each side. My friend designed and built these with me as his shop assistant and employer. There really is something to the effortlessness of that bass.
That’s a seriously capable bass horn setup - kudos. What’s the tune?
Even the best direct radiator bass has a sound of grippy force and power, like something is working hard.
Exactly, I find this to be the case in the sub range in particular, where cone movement can be prodigious. I do run dual 15" high eff. direct radiating mid-woofers per channel covering ~85 to 600Hz, which feels like they’re converted to rockets being rid of most everything below their high-pass point; the cones here move zilch even at close to war volume. However, horn-loading the bass/lower mids in this area with a horn big enough can make wonders.
Horn loaded bass doesn’t require nearly as much power to produce plenty of volume and it comes across somehow as sublime. At a quite loud 30Hz those drivers are barely moving.
+1
At the present moment I’m in the process of moving in to a new place and it will be a while before I can get the bass horns back in action. for now I’m listening with 2 10" conventional subwoofers. They’re way better than not having them and it’s enjoyable - but nowhere near the same. Obviously it would be closer if I had 8 of them in the room stacked in the corners instead of just 2 and they were all 18" instead of 10", so yeah, not a fair comparison.
Hope you’ll be up and running with your 18" octet-loaded bass horns in the foreseeable future. I must be a challenge living with less once used to such an all-out horn bass setup!
@kota1, absolutely not. I have a unique problem in that my speakers are full range line sources. In order for a subwoofer system to keep up with them the subwoofers need to form a linear array. On a 16 foot wall that requires at least 4 separate subwoofers. Also, the more drivers you use the lower the distortion and the more power you can radiate out into the space. I want to be able to put a Nine Inch Nails concert in my media room.
Speaking of subs and rooms, I have to add the general trend toward smaller subs in higher quantity is proving to be a better solution for most rooms and studios. The desire for one big sub creates dominant rooms modes that are a bear to remove with giant nulls and huge peaks. Although counter intuitive, adding more does indeed create more modes, but fewer are dominant. We lose the lack of bass in one part of the room and the over abundance in another. Locating 4 subs on 4 different walls at varying distances from corners can be a revelation. Forget the stereo thing below 100Hz, sum it to mono and it can be very surprising.
In studios, its a common complaint to have bass build up on the back wall (the wall behind you) so you always put the client couch there; he or she hears lots of bass and usually likes it. At the mix position different story. In studios were multiple people are working simultaneously in sessions such as tracking, scoring recording, the band in the control room while drums are tracked etc, good off axis performance of monitors and smooth room coverage of low end is much preferred.
Duke, who posts on this forum, has been espousing this multi sub solution for years.
Wow what a great chat very interesting and enjoyable! Made me miss my powered Acustat X’s with the tube amps built in and my Martin Logan Purity’s 🌝I think ML missed the boat not doing another better pair of powered speakers even if I’m not a fan a D class Amps The convenience is killer at a certain level. Thanks to everyone in the chat was a nice conversation indeed!
Speaking of subs and rooms, I have to add the general trend toward smaller subs in higher quantity is proving to be a better solution for most rooms and studios. The desire for one big sub creates dominant rooms modes that are a bear to remove with giant nulls and huge peaks.
One doesn't exclude the other. Certainly in the context of my bringing up large subs it's with the outset of using two of them and no less, and more where permits and/or is willed/decided. What's most important is having the larger pair of subs placed along the front wall (preferably symmetrical to the mains); any addition of subs no. 3, 4 or more for a DBA can be significantly smaller and needn't be as extension capable/covering the same range as the larger ones; they'll still fulfill their "job" as extra bass sources to make for an acoustically smoother response.
Although counter intuitive, adding more does indeed create more modes, but fewer are dominant. We lose the lack of bass in one part of the room and the over abundance in another. Locating 4 subs on 4 different walls at varying distances from corners can be a revelation. Forget the stereo thing below 100Hz, sum it to mono and it can be very surprising.
I find crossing subs even lower than 80Hz to necessitate symmetry-to-the-mains placement and stereo coupling. Most subs aren't low-passed with brick wall-steep slopes, and so the sloping response "bleeds" into the upper range to make for directional awareness. Moreover it can be argued whether the 80Hz barrier of "loss of directionality"-claim holds general credence. To me it's not a hard numerical value but rather a frequency range within which directionality gradually lets go, and extends further down than the oft claimed 80Hz.
Crossing higher than 60-70Hz at least while high-passing the mains I find symmetry-to-the-mains placement of subs to be paramount, and just has the whole sphere of sound snap more effectively into place. An asymmetrically placed DBA to me sounds more like headphone/inside the head bass, which isn't natural to me. I know many disagree, so be it; I'm keenly sensitive to symmetry placement and stereo coupling of subs, and so act accordingly when implementing subs.
Good arguments all Phusis. I can think of locations we’ve been involved in where symmetry worked; other places it did not. Visually we are always drawn to symmetry. My clients want the subs right under the mains and this "looks right". But most of the acousticians I know would argue against it, even if the physical offset is smaller than they are asking for. Their argument is that both subs at 12 feet from a corner sets up a mode relating to 12 feet in length. One at 12.5 and one at 11 is better. 4 subs should be at 4 different lengths from corners. An alternative plan is an array of all 4 subs next to each other on the front wall but we can leave that for another time.
One difference may be that in my applications, the mains are NOT high passed. The argument is that all crossovers create a hole (a dip at the crossover point itself) which is increased with increasing slope of the crossover. In studios, a 48dB slope is a big NO. Most of our applications have a 12dB slope, minimizing that dip. Introducing a dip right at 100 or 80 or even 60 is very noticeable and counter intuitve to the goal of "more bass". The other issue is phase and the introduction of another phase shift that is not wanted. Subs are low passed, usually with gentle slopes.
In all types of music now, we see extraordinary low end being inserted at the artist behest. London Grammar’s "Hey Now" is adjust such an example of unexpected but likable low end.
In our business, a filter to make sure a speaker rolls off at a new higher place is not desired, as now we have added something that makes a sound across the mains and changes them. Even in the case of a simple and well executed LF filter, it is audible. In this application, low passing subs and not filtering anything on the mains is the basic idea. Subs are usually sealed, have no EQ and no DSP of any kind. Blending them can be a relatively easy process and sometimes requires inverted polarity (180) to make work. Depending on arotating phase control, which only works over a portion of the sub band, is not the fix but a fine tune.
In large rooms one wishes for DSP to create a delay of the mains to match up to the subs, but this is often not accepted due to the audible change the DSP introduces plus the barely noticeable delay created by DSP. Any offset in time makes tracking odd, sometimes difficult where one artist is in the live room and one is the control room- both being recorded at the same time. If the entire system is DSP driven that may be a different scenario, but with ATC we prefer 100% analog output to speaker.
Sorry @lonemountainbut high passing mains,. especially residential is often the right thing to do, and done right, with quality subs and filtering on both is inaudible. There will be no shift in tone and no localization is possible. You have to be cutting off below the Schrodinger frequency. Your subs have to be low distortion, especially anything third order and higher. That may be as much a consideration for where you're cut off frequency is as anything. If you've got large means that can play low distortion at high volumes at base frequencies, then I would consider it beneficial to run them full range. But most mains these days don't fit that criteria. For most means I would far prefer a cut off that's not full range especially if the customer likes high volume levels.
I don't understand your comment with respect to DSP. With any modern half decent quality ADC, you're not going to hear any sound of using an ADC and then DSP. And of course if it's an all digital system, it's a nonstarter. Talking about DSP delay is also not relevant when you bring up in the same paragraph 180° out of phase operation which is a delay. There are no absolutes speakers like a line array can be difficult to integrate with subs and an evaluation needs to be done based on mains speakers, room size, listening levels etc
@kota1phasing sub and full range speakers is not difficult, just put you head exactly between the sub and the speakers, play and 80hz tone with all your equipment on and slowly turn the phase knob until you hear the null point and the strongest point. Go back and forth to be sure you are not 180 degrees off, stop at the strongest tone.
@lonemountain, I beg to differ Brad. Subs belong in corners. That is where they are most efficient. I have been using digital signal processing including full range room control for 25 years. My main speakers are ESLs and I high pass them at 100 Hz. The result is far less distortion and much higher volumes. The advantage will not be as great for multiway dynamic speakers but still detectible. IMHO digital signal processing done right is a boon to overall system performance for a multitude of reasons not just subwoofer crossover. You can not perfectly match your channels any other way not to mention tuning your system exactly the way you want it. I even use dynamic loudness filters. The system sounds exactly the same regardless of volume.
The best way, IMHO, to manage subs is to put them where they are most efficient using at least two in a symmetrical array with the main speakers, cross them steeply (48 dB/oct at least) using matching high pass filters on the mains putting the crossover point 6 dB down. Then matching the subs in time and phase with the main speakers. I would argue that if a symmetrical array can not be done due to room issues then it is the wrong room for a HiFi system. I have set up systems in rooms I would have never used for HiFi and made the best of it but I always warned the person the situation was not optimal. Most people do not care. They listen to music but do not imagine it. To them an image is something coming from the right and something else coming from the left.
I can very much appreciate the experience of others. SpeakerDude, yes, the speakers in question are good down low without subs, almost always a 2nd order roll off. All analog from a good converter, usually a Burl. Target for max SPL (for dynamics) is 100 to 110dB SPL.
Mijosten, I appreciate corners are where subs can have the most boundary gain but corners are rarely available in a studio. They are frequently occupied with gear or bass traps. Somewhere along the floor where it meets the wall is usually the best available location, with only 3dB less boost than the corner. Sub arrays are certainly a goal but its extremely rare to have a studio actually allocate the control room space (often living room sized) to implement one. In 25 years I have not seen a single studio example. In live or fixed install, I have seen many examples.
Is this the conflict of the practical vs the theoretical?
Apologies I used voice dictation for my last post and it changed mains to means several times. So much for context sensitive dictation :-)
@lonemountainif you are low passing the subs at only 2nd order (12db/octave) then you pretty much have to run the mains full range. Even 24db/octave is not enough with a high cutoff if you want to prevent localization. Analog filtering on the subs can often cause phase integration issues with the mains. 2nd order will have less phase issues, but has the aforementioned issues. DSP filtering is by far best for subs.
@mijostyn- Corner loading a sub may be the best option for a room, or it may not be. If it is bad for a given room and that room has symmetry, you quite often create more problems than you solve. It would be far more often the case with two subs that pulling them forward on the opposing walls out of the corners would result in more even bass and better use of available power. Your subs will only have some limited line array effect as the line is wall-to-wall, and the floor is right there, so you already have one immediate reflection, but if it behaves as a line array, the front wall-back wall room mode is amplified. Your crossover is below the Shrodinger frequency.
So I got to run my new Sony TA-ZH1ES dac/pre/headphone amp as a pure 2 ch preamp today, sans subs, just in 2.0. I haven’t listened to a system without dsp in this room in a long time (ever?) and although the Sony’s sound is more pure to the original recording it loses a step in sound staging and overall smoothness compared to my Marantz processor in Pure Direct mode which includes the benefit of the subs and room EQ. I might tinker with setting up the subs and dsp with the Sony after the holidays but for now am just going to enjoy it as a dac feeding my Marantz processor.
@thespeakerdude, If a subwoofer driver is right against a wall (in a corner) as part of a line array on the floor there is no first reflection until you get to the ceiling. The wave is beginning at the wall (no delay). A line array does not radiate past it's ends. If the array is horizontal against a wall those ends are in the corner. This is unique to my situation as my main speakers are line sources. Most people have point source systems and such a subwoofer array would overpower their system. People with point source systems are better off with two subwoofers. Corner placement minimizes the effect of reflections because the driver is up against three surfaces instead of two or none if the speakers are away from the front wall. With subs in the corner the first reflections that are delayed are off the ceiling, opposite wall and back wall. By the time they get back to the listener they are late reflections and not as serious. At high frequencies things get more complicated, one of the main reasons dipoles sound better. The biggest problem with putting subs in the corner at a different distance from the listener as the mains is phase an timing. To make this work you have to use digital signal processing to delay speakers so everything arrives at the listening position in phase at the exact same time. Most people without signal processing are better off with the two woofers any where in the room at the same radial distance as the main speakers from the listener, classically this was between the main speakers but does not have to be.
@juanmanuelfangioii, I think you should change your moniker which is an insult to the greatest racing driver of all time and a great person.
@mijostyn, your bass "line array" goes from left wall to right wall, well in theory, and includes the walls as reflectors to extend the virtual length of the array (again in theory and needed for low frequencies). The floor is still a first reflection point, though it barely matters since your subs appear to be working purely below the Schroeder frequency (again, thank you Google!). Thinking of it as a line array is giving you an inaccurate perception of how the bass is behaving in your room or any potential gain advantage beyond room gain.
Talking about late reflections (or early reflections) in bass has little practical relevance. That is not how we hear bass. You cannot decouple how we hear from the acoustics. Also when talking phase, it is important to clarify phase during cross-over so you don't introduce an additional peak or null during transition at the listening position. However, back to Shroeder frequency and real rooms, we are never dealing with single waves with bass, we are dealing with mode dominated spaces. The coordinated arrival of first waves from the various drivers is less critical than how the modal field develops, in the typical room that is not able to damp bass much at these frequencies. That is why bringing the subs out along the walls into the room often works better. The reductions of peaks and valleys from modal excitation is less critical than first arrival phasing which you cannot hear.
I realize most subs are active speakers but this topic belongs in a new thread, (Bassaholics Anonymous?) Can we get back to the thread topic of active speakers and the confusion surrounding them?
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