To do that you have to say stuff that's true.
Do you need links or something to satisfy that, or is this one of those things where no matter how much fact is presented, nothing will change?
Ron’s New System
- Thread starter Ron Resnick
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Do you need links or something to satisfy that, or is this one of those things where no matter how much fact is presented, nothing will change?
At one point I bought into the idea that bass below 80Hz is not localizable and the it takes 3 cycles to determine pitch, and the bass waves are so long that phase isn't a thing. I bought 4 pretty high level subwoofers and began to experiment with 1, 2, 3 and 4 subwoofers. I read the Todd Welti and the Earl Geddes stuff and worked on the distributed bass aray ideas. What I determined is that it does deliver on it promise of flat frequency response. I also determined that one doesn't need 3 or 4 subwoofers to do this for a single listing position. Two is a sufficient number if all you want is a flat frequency response at the listening position. The easiest way to implement this is with a program called Multi Sub Optimizer (MSO). Using this program you will achieve ruler flat frequency response without much effort.
One key thing to point out about Todd Welti and Earl Geddes ideas: they were both trying to achieve uniform bass response over a wide area. The idea was driven by home theater application and not music reproduction.
The primary problem with adding subwoofers to a pair of stereo speakers is transient response. If not critically aligned with the main speakers, there will be time smearing. Of course, if the main speakers are not well aligned to begin with then it is easier to fit the subwoofers in the envelope (so to speak). This could be why two people have different optinions about the efficacy of DBA.
There is theory and there is observation. Theory may say that we can't localize below 80Hz and wavelenghts are so long they have bounced around the room before we hear them and so on. However, this does not agree with my observation. In a stereo system with two subwoofers crossed over at 30Hz with a 24 dB/Oct slope, I can move any object in the soundfield using just one subwoofer. For example, it is quite easy to move the position of an oboe by slight positional changes to just one subwoofer. Also, it is very easy to hear that a bass drum beat is aligned (or not) with the same oboe on the beat.
One last thing to thing to consider. Music is not a sine wave. Listen to the opening of Rossini's La Scala Di Seta and ask yourself if that sounds like a sine wave.
Just my 2c.
One key thing to point out about Todd Welti and Earl Geddes ideas: they were both trying to achieve uniform bass response over a wide area. The idea was driven by home theater application and not music reproduction.
The primary problem with adding subwoofers to a pair of stereo speakers is transient response. If not critically aligned with the main speakers, there will be time smearing. Of course, if the main speakers are not well aligned to begin with then it is easier to fit the subwoofers in the envelope (so to speak). This could be why two people have different optinions about the efficacy of DBA.
There is theory and there is observation. Theory may say that we can't localize below 80Hz and wavelenghts are so long they have bounced around the room before we hear them and so on. However, this does not agree with my observation. In a stereo system with two subwoofers crossed over at 30Hz with a 24 dB/Oct slope, I can move any object in the soundfield using just one subwoofer. For example, it is quite easy to move the position of an oboe by slight positional changes to just one subwoofer. Also, it is very easy to hear that a bass drum beat is aligned (or not) with the same oboe on the beat.
One last thing to thing to consider. Music is not a sine wave. Listen to the opening of Rossini's La Scala Di Seta and ask yourself if that sounds like a sine wave.
Just my 2c.
I found out a long time ago that you can't sort out a standing wave in the room using any kind of software.
The reason is the software will simply ask the amps to make more power at the problematic frequency. But standing waves are cancelling energy which means you could dump 1000 Watts into that null and not fix it.
Since this sort of problem is usually happening below 80 the DBA makes good sense as it sorts that problem right out, especially in smaller rooms.
That is actually all I use, since my main speakers are flat to 20Hz. Essentially its still a DBA though as the main speakers are part of the array.
Even crossed very low subs have some harmonic distortion - these frequencies can be perceived. But this an added artifact.
No, it sounds like a superposition of sine waves - better said, any musical sound can be represented as a superposition of sine waves ... We listen to such representation in our systems.
The same musical signal can be represented a superposition of any complete set of basis functions. e.g. bessel functions or spherical harmonics or many others. Sine and Cosine are easy to grasp because a pure tone that lasts for some duration is an oscillation. Music is not a pure tone. The point I was making with the Rossini piece is that in a large scale music is really a series of impulses (transients). Unless precisely aligned, the multiple drivers that make up a stereo system muddy and confuse the sound. This includes subwoofers.
That is true of a high Q single standing wave dip but most dips and peaks are the result of summation of multiple standing waves and have a low Q component .. most software smooths the measurement and does not correct the high Q component so you can correct dips up to a point... this seems to be perceived as flat in my experience. ( I expect similar things are going on with distributed bass array)
The only issue is that you are subtracting energy so you need a lot of headroom to begin with...not the path that some people want to travel
What you are correcting is the "reveberent" field which tends to support your argument that perception of bass relies on reflections to fully develop, however there is no doubt that your ears experience that pressure wave when it first travels past you and I suspect that it provides localisation cues.
The often qouted limits of localisation .. 120,80 hz etc. I think are a rationisation of the fact that we did not have the tools for precision untill recently
Thats it from me
P
This is an interesting way to describe it. I like it. I think of it as removing information from the room. Sound from musical instruments is energy. I ultimately discovered that information or energy was removed when I added tube traps to my room. Certain energy was subtracted, which resulted in the perceived enhancement of other frequencies. Over time, I came to realize that I did not want to remove energy but rather manage it, so I removed the tube traps from my room and worked more on speaker positioning and later added diffusion.
Peter ... in this case what I am referring to is the reduction of volume of parts of the signal to achieve a flat response .. or whatever target you are chasing .. in that case you ultimately are reproducing what is on the recording and hence more natural... we hope.
Passive crossovers do the same but dont have much flexibility, mess up quite a bit of the signal and are difficult to match.
But if you are trying to overcome a room dip in the dsp world the level you reduce it to is defined by how far down the dip you want to go( at least in programs I have used)
So you throw away a lot of energy .. so drivers, amps etc. have to have a lot of headroom.
Way better of course to minimize dips or only do minor correction.
In the case of traps you are absorbing reverbarent energy rather than flattening the direct signal and maybe the room sounds too dry as a result.
I fell somewhat the same. I have very little experience. But I don't have some super power system. I have 40 watt amps and a 500 watt sub. I don't want to be absorbing energy in my room. I want to use all of it. But do it in a way that does not create issues. I do have better bass with a large absorber in the room. A bed. But I am sure I would have a whole lot better bass if I had a swarm instead of that bed.
my active (2000 watts on each tower) MM7 bass towers (extend to -3db @ 7hz, -6db @ 3hz on paper) cross over at 37hz to my main towers.
if i turn them off the soundstage collapses to a small but noticeable degree (even though localization in theory does not happen in that frequency range) and the highs are less complete/natural. overtones from the deep bass flesh out the soundstage including high frequencies. on 2/3rds of the music the passive towers sound good by themselves. but 1/3rd of the music something is missing objectively. the passive towers are designed to only work with the bass towers. a completely integrated design. i have them set up equa-distant to my listening position with my passive main towers for a time aligned wave launch.
bottom octave linear extension pays dividends everywhere.
the room does have 4 floor to 11' ceiling built in (14" x 12" x 11') bass traps in the rear wall. and the large cold air returns in the front corners likely do some degree of bass trapping too.
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Elliot G.
Dealer - Bending Wave
Your room does have good bass this is not however something that the majority of systems have. We just got finished at CAPFEST and the system was really successful because the bass was right and maybe for the first time we conquered the space perfectly. There is no escaping the time and experience factors. I got involved with the speakers I import because Oliver get's the bass right. Having bass is not the same as the bass being fully integrated and blended into the speakers.IMO most speakers play music in an unintegrated fashion. Some have great mids and highs and little bass and others have the apples and oranges playback. You may scoff and laugh but to me the bass lives and breaths in many like a separated passenger. This to me is not something I like and can live with. All the language here is above my pay grade and scientific expertise but I do know that when I set the stuff up there are things that are required. I am not a fan of high level, I am not of fan of none or little phase angle adjustments. One must position a sub or a pair of subs with the same intensity and care as one does with the main speakers. It also helps to be able to adjust settings from the listening position/possessions and from experience this takes a bunch of time to get it right.
If you can hear them it's wrong is what i believe.
My two cents. Tech is great but knowing how to use the tech to get the result far more important and difficult
You do have to get the bass right! The ear has a sort of built in tone control; if bass is missing the perception will be tilted to the highs. That can mess with how you perceive the sound stage. So if the bass is right a benefit is the highs seem smoother and more relaxed.
Elliot G.
Dealer - Bending Wave
this is also very correct when integrating subs, since most don't get it right it corrupts and ruins the entire system IMO.
coherence and flow always win musically over extension.
Yes, !
for myself that is so easy to recognise/ prove. Turn the subs off-something is missing, the soundstage contacts, also the overall in room tone becomes leaner and sounds strained or more forced. Like you are asking mini monitors to fill (pressurise) a large space.
I can adjust the bass/sub level relative to the mains on the fly, you can hear what happens when it’s balanced.
I like how you describe the sensation as being similar to a tone control. Too much obscures details, the sound become fat, lazy, slow and thick. With the ratio balanced the sound is smoother, music has more weight and impact, without any loss of detail.
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Yes, but these transients are also just a superposition of sine waves. Many people attribute magical properties to transients, but they are the same type of signal as common music. They have usually more power and a broader frequency spectrum than common music, that need specific technical requirements of systems, but are not intrinsically different.
Time alignment is a controversy subject - I have listened to excellent sound in several kind of systems, time aligned or not. I usually align the subwoofers using instruments, but after I get the best technical alignment I change it slightly by listening.
Yeah-no.
Maybe a mathematician can conjure up that they are equivalent, but everyone else knows that wood winds, strings, etc are designed to resonate and specific frequencies.
Percussive instruments are different, and a whole different section of its one in the band or orchestra.
True
They may have more instantaneous energy, so higher power.
Ignoring any double entandres, it is easier to get knocked out with a punch than blown over by the breath
Which in the same way that arm swinging a mallot can deliver a lot of energy into a drum.
However there is only one technically right answer.Time alignment is a controversy subject - I have listened to excellent sound in several kind of systems, time aligned or not. I usually align the subwoofers using instruments, but after I get the best technical alignment I change it slightly by listening.
If the system cannot replicate the signal that it was presented, then it is not faithful, and hence has lower fidelity,
That all sort of falls apart at the low frequencies with a typical room, so some seasoning to taste is done..
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