+1 millercarbon Bass tube traps, imho, are big, expensive, ugly as sin and are completely unnecessary if you invest in this instead: https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/ This distributed bass array system will provide sota bass response in any room and seamlessly integrate with any pair of main speakers. It'll also look a helluva better in your room than bass traps. I've been using this with large Magnepan panels for the last 4 yrs and can verify the review is very accurate. Tim |
zardozmike,
Simple, just buy and install the AK Swarm and forget about bass traps, room correction software/hardware, Helmholtz resonators, mijostyn and Mr. Rocket Science forever.
Tim
|
dtximages:
"Or just buy more subs. I don’t see anything magical about the AK Swarm. What I gathered is that 4 subs, semi-carefully placed will essentially do a better job of EQ-ing itself than room correction software"
Hello dxtimages,
You're correct, the key to the distributed bass array (DBA) concept's effectiveness is having 4 subs distributed throughout the room and anyone can create their own custom DBA system using any subs they prefer. Four small DIY subs or four huge and expensive JL Audio subs, or any subs in between, will work. The DBA concept is scalable and flexible and provides accurate, detailed, smooth and natural bass response in virtually any room and seamlessly integrates this bass with any pair of speakers, even fast planar-magnetic and electrostatic speakers.
You're also correct that you don't see anything magical about the AK Swarm or a custom DBA system, all the magic is heard and felt but not seen.
Tim
|
geoffkait:
"In the case of the much maligned CD not very much of the bass frequencies are coming through anyway so what’s the difference?"
Hello Mr. Rocket Science,
True RS, most cds and vinyl recordings only contain summed mono bass from 20 to about 100 Hz but reproducing whatever bass there is on the source material with high fidelity is still important for an optimum listening experience.
Tim
|
jon_5912:
"Has anyone ever tried having a single big sub and a few more smaller ones? I'd think a single sub that goes to 20hz would be enough and then 3 smaller ones that only maybe go down to 30hz could be used to even out the response. Locate the big one in the best spot for very deep bass and the other three can even out the response from 30-80hz. There tends to be a huge price difference between subs that will go to 20hz vs 30."
Hello jon,
Very good question. I've never tried this myself but I don't believe there's any reason this wouldn't provide accurate, detailed, smooth and natural bass with deep bass extension down to 20 Hz. I suspect, however, having only one sub extending down to 20 Hz might limit the power and impact heard and felt at that deep bass frequency. But It may be possible to compensate by having the volume set higher on the sub that goes to 20 Hz or you could always use two and still be saving money, just a bit less.
You should also probably go look and hear some subs, 30 Hz sounds and feels quite deep and may be sufficient for some.
Tim
|
geoffkait:
">>>I’m afraid you missed my point. The bass information’s there on the disc, and tons of it, it just isn’t being retrieved properly or completely - not by a long shot! - As fate would have it the CD playback systems are plagued by a number of technical problems even after all these years that prevent a lot of information from getting to the speakers. Primarily, scattered light and vibration of the CD itself, but also some other problems."
Hello geoffkait,
Yes, I did miss your point. Maybe if you didn’t wear that huge hat, your point would be more easily seen. Oh, Wow! Wowie Wow Wow! Now that you’re hat’s off and I’m closer, I can see you obviously have a very significant point there. Oh my god! No way! What the....Wow, maybe you should put your huge cowboy hat back on now, that point you have there on your head is really freaking me out!
Anyway, I completely agree with you that CD recording and playback does have its problems and has the capacity and potential to be of much higher quality. Those issues you mentioned and the serious issue of compressed dynamics (Loudness wars) caused me to now use less CD content and more 24bit/96KHz FLAC downloads, especially those recorded direct to digital.
However, this thread was started inquiring about bass room treatments and my suggestion was to invest in a better bass system like a DBA instead. While I believe the subjects of the quality of CD recordings and playback are very valid and important ones, I think it may be better suited for its own thread or threads.
Tim
|
mijostyn:
"
Tim, I think you should find a job as a used car salesman, excuse me salesperson.
Actually summed bass below 100 Hz is an advantage in most acoustic situations you would have in the typical home."
Hello mijostyn,
No thanks, I enjoy being semi-retired and performing only the occasional brain surgery.
All 4 of the subs in my system are run as mono and I have no current issues with summed bass below 100 Hz, although those wanting or expecting stereo deep bass from their systems will likely be disappointed.
mijostyn:
"
Back to Tim, The term "room control" is a misnomer. You are not controlling the room. You are controlling the speaker to correct response abnormalities of the speaker/room system, to make both sides have exactly the same response and correct timing so that the sound from each driver hits the listening position at exactly the same time."
I don't recall ever using the term "room control". However, I do understand the 4-sub DBA concept works so well due to creating numerous well dispersed additional bass room modes (bass peaks and dips) at various frequencies in the room. And I understand the psycho acoustics identified principle of our brains processing these numerous varied bass room modes by averaging them out which results in the perception of the bass as accurate, detailed, fast, smooth and natural. But I agree with you that this is properly described as controlling the speakers to correct abnormalities of the speaker/room system, not as "room control".
The time domain aspect, or the timing of bass sound waves reaching the listening position, is of much less importance for deep bass frequencies than it is for mid-range and treble frequencies. We're actually not very sensitive to arrival time in the bass region. It's been proven that we don't even hear a deep bass frequency until the full duty cycle of the frequency sound wave has been released into the room. In other words, we cannot detect the presence of bass from less than one full wavelength. We also need to hear multiple full wavelengths before we can detect pitch. A 56 foot 20 Hz sound wave released into a normal sized room means it is going to bounce or reflect at least once before the entire duty cycle is detected and be able to be heard at the listening position. We also need to detect multiple cycles at the listening position to determine pitch.
This implies that relatively small timing differences - 'small' relative to the wavelengths in the bass region - are not going to make an audible difference in and of themselves.
I think you're stating there's a requirement for the "correct timing so that the sound from each driver hits the listening position at exactly the same time"
seems unreasonable and unlikely given the reality of our bass sound wave perception capabilities.
Tim |
jon_5912:
"The reason I ask about adding smaller subs to a big one is that I, like a lot of people I'm sure, already have one big expensive sub. I would never buy three more like it. I measured the response with the Behringer ultracurve and measurement mic, and equalized out the worst of the problems. I'm not unhappy with it how it is but if I could add a few smaller, cheaper subs and get a dramatic improvement I might consider it."
Hello jon_5912,
I think you may have missed my response to your question earlier in this thread. Here it is again:
Hello jon,
Very good question. I've never tried this myself but I don't believe there's any reason this wouldn't provide accurate, detailed, smooth and natural bass with deep bass extension down to 20 Hz. I suspect, however, having only one sub extending down to 20 Hz might limit the power and impact heard and felt at that deep bass frequency. But It may be possible to compensate by having the volume set higher on the sub that goes to 20 Hz or you could always use two and still be saving money, just a bit less.
You should also probably go look and hear some subs, 30 Hz sounds and feels quite deep and may be sufficient for some.
Tim
|
Using large, expensive and butt-ugly bass traps always seemed analogous to opening windows in mid-winter to control the heat in your house. Better to control it at the source, right?
Like turning down the thermostat to reduce the heat or use a 4-sub DBA system to optimize your room's bass response and sell your bass traps.
Tim
|
jtcf: "
Check this out: https://www.psiaudio.swiss/avaa-c20-active-bass-trap/It looks to me like an expensive alternative to the DBA system
Hello jtcf, It seems to me the active bass trap and the distributed bass array (DBA) system operate on almost opposite principles. As I understand the active bass trap (ABT) , it uses a built in mic to identify room bass modes, that are within its limited range and up to 150 Hz, and uses openings in its surface to somehow draw these sound waves into its inner chamber and, through an unexplained process, eliminates or attenuates these room bass modes. I believe it's only able to identify bass modes that are peaks and not dips but I'm not certain. The DBA, on the other hand, takes the opposite approach of distributing 4 subs in the room in order to create many more bass modes (both peaks and dips) throughout the room and then relies on some scientifically proven and well understood psycho acoustic principles. The following are the relevant psycho acoustic principles that the DBA concept relies upon: 1. Humans are very adept at determining the originating locations (the source) of sounds with frequencies above about 100 Hz, with this ability improving as the sound frequency increases. 2. Humans generally are unable to determine the originating locations of sounds below about 100 Hz but are adept at discerning the volume and pitch, as well as changes in volume and pitch, in these deep bass tones. 3. We need to hear the complete duty cycle of a deep bass tone frequency (the complete bass sound wave cycle from beginning to end is called a duty cycle and it needs to exist in the room) before we're consciously aware of the bass sound. If less than a complete duty cycle exists in the room, then no bass sound is detected. This is relevant when the length of the sound wave exceeds any of the room's dimensions; a 20 Hz tone has a total length of 56 feet, so it needs to reflect off a room surface at least once, depending on the room dimensions, before we actually discern the bass sound. 4. We need to detect multiple complete duty cycles of a bass tone frequency to determine pitch. 5. When we detect multiple bass sound waves and bass modes (peaks and dips) at various frequencies in a room, our brains process this by summing and averaging these. This psycho acoustic principle is the key to the DBA concept being such an effective bass solution. Of course, all of these psycho acoustic dynamics described above are taking place at a subconscious level and we're just aware of how detailed, fast, dynamic, impactful, smooth, natural and perfectly blended and integrated with the main speakers the bass sounds. I realize I'm seemingly constantly extolling the virtues of the DBA concept and its only relevance to this thread is that it requires no acoustic treatments, no room correction software or hardware, minimal equalization and no DSP. My main intent is really just to spread the word on how well the DBA concept actually works. I honestly don't believe it's possible for me to overstate how well this bass solution performs in my system and room. There's also no typical warning of ymmv (your mileage may vary) necessary since the DBA concept performs extremely well in virtually any room and with any pair of main speakers. So I'll coin a new acronym exclusively for audio solutions that will work for others without qualifications: ymwnv (your mileage will not vary). Tim |
Hi jtcf,
I just came up with the acronym ABT (automatic bass trap) to avoid having to use its full name on my last post.
I restrained from stating it didn't work because I've never tried them and, therefore, I'm not qualified to have an opinion.
My opinion is that good bass response is very important but one of the most difficult qualities to achieve in a home audio system. I actually consider my system as two systems: a bass system and a midrange/treble and stereo imaging system.
I also prefer a system focused on producing good bass than one trying to improve bass that's already been produced in the room.
Later,
Tim |
b_limo: "@noble100, Correction, does a DBA system, or a SBA too, sound better in a treated room compared to an untreated room?"
Hello b_limo,
DBA is an initialism for distributed bass array.
My 4-sub DBA system is in an untreated room and functions very well. I can't imagine how any bass room treatments would be beneficial. The DBA concept works best when bass soundwaves are allowed to freely reflect off room boundaries, I think any room bass treatments that would impede these bass soundwave reflections likely would also impede the effectiveness of the DBA system.
Sorry, I don't know what an SBA is.
Tim
|
mijostyn:
"Boy are you out to lunch on this one Tim. It is not what you hear. It is about what you feel. I would bet that you have never played with a system in which you can control phase and arrival times which is why you have this rather flaky opinion. This makes a major difference in the realism of the system. Just wire one sub out of phase and see what you get. I've got news for you. You have to be in phase the entire cross over region. If you are 1/2 wavelength out of time you have one sub wired backwards. This would be the kind of biased unacceptable opinion you swarm guys would come up with. If you think the bass you have now is good, you have a long way to go. "
Hello mijostyn,
Sorry I'm so late getting back to you, we went out for lunch and we waited about 3 months for our food! So, I literally have been out to lunch.
I feel like you have a poor understanding in general about how and why the Swarm 4-sub distributed bass array (DBA) concept works so exceptionally well. Here's a summary of some key DBA concept info to help you grasp it:
-Phase is important and the Swarm's phase can be continuously adjusted for the 4 subs as a group on the amp/control unit. Also, during the setup process one of the final steps is to reverse the phase on each sub individually to make sure the bass doesn't sound better with one of the sub's phase reversed.
-The fact is that the very long bass soundwaves behave very differently than the much shorter midrange and treble soundwaves in typical domestic rooms.
-This makes sense since a full-cycle 20 Hz deep bass soundwave is about 56' long while a 20,000 Hz full-cycle high treble soundwave is a fraction of an inch long.
- It's been proven that we don't even hear a deep bass frequency under 80 Hz until the full duty cycle of the frequency sound wave has been released into the room, our ears have transmitted the details of the full-cycle deep bass soundwave to the brain and our brain processes this info as the perception of a deep bass tone present in the room.
-In other words, we cannot detect the presence of bass under 80 Hz from less than one full wavelength.
-We also need to hear multiple full wavelengths of bass under 80 Hz before we can detect pitch and volume. A 56 foot 20 Hz sound wave released into a normal sized room means it is going to bounce or reflect at least once before the entire duty cycle is detected and be able to be heard at the listening position. We also need to detect multiple cycles at the listening position to determine pitch and volume.
-This implies that relatively small timing differences - 'small' relative to the wavelengths in the under 80 Hz bass region - are not going to make an audible difference in and of themselves.
-The time domain aspect, or the timing of bass sound waves reaching the listening position, is of much less importance for deep bass frequencies than it is for mid-range and treble frequencies. We're actually not very sensitive to arrival time in the bass region.
-There's no requirement for the correct timing so that the sound from each bass driver hits the listening position at exactly the same time like there is with the midrange and treble drivers.
-The 4-sub DBA concept works so well due to creating numerous well dispersed additional bass room modes (bass peaks and dips) at various frequencies in the room.
-The psychoacoustics identified principle of our brains processing these numerous varied bass room modes by averaging them out results in the perception of the bass as accurate, detailed, fast, smooth and natural.
-This is properly described as controlling the speakers to correct abnormalities of the speaker/room system, not as "room control".
Tim
|
|
|
Hello clearthink, This is a paper by Todd Welti of Harman International, who studied under Dr. Earl Geddes. He specifically also states that bass under 80 Hz is not directional or localized. ttps:// www.harman.com/sites/default/files/multsubs_0.pdf |
clearthink, I'm on another thread right now posting back and forth with Duke Lejeune, Audio Kinesis owner who designed and sells the Swarm 4-sub DBA system I use. Here's a post quote from him today: "@noble100 wrote: "Duke... I was hoping to get your honest opinion on my thoughts on how I understand multiple sub systems function in general as well as my understanding of how bass is recorded on CDs and vinyl." In general I agree with what you wrote, so let me just toss out a few comments. " We all are unable to localize deep bass frequency soundwaves..." My understanding is that’s generally true in a room. The figure I use is 80 Hz, rather than 100 Hz. I think Floyd Toole uses 80 Hz. This doesn’t necessarily mean that one cannot detect the location of a sub which is crossed over significantly lower, say at 40 Hz, because crossovers are not brick walls, so upper bass/lower midrange energy can give away a sub’s location if it comes through loud enough. Therefore in my opinion a steep lowpass filter on the sub helps to hide its location. "the bass is summed to mono on frequencies below 100 Hz on all vinyl and cd recordings." I wouldn’t say "all", but I would say "almost all". (If we’re talking about a Swarm/DEBRA system, a second amp can be added to give you true stereo bass). "Our brains are able to associate the fundamental deep bass frequencies reproduced by the subs, that are not able to be localized, with the deep bass’s higher harmonic frequencies, that extend well beyond 100 Hz, which are reproduced by the main speakers that are able to be localized. This psychoacoustic association allows us to localize the deep bass in the soundstage, for example the kick drum is located in the rear center and the upright bass is located in the front to the left, which would not be otherwise possible without this psychoacoustic association our brain’s are capable of." I agree. Duke" Here's the thread link: https://forum.audiogon.com/discussions/searching-for-matching-subwoofer-solution?page=2Tim |
