Ron’s New System

[Atmasphere]

As was that .. but fair enough .. just trying to break through the false barrier

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?

 

[sbnx]

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.

 

[Holmz]

As was that .. but fair enough .. just trying to break through the false barrier

The ear drum?

 

[Atmasphere]

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.

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.

Two is a sufficient number if all you want is a flat frequency response at the listening position.

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.

 

[microstrip]

(...) 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.

Even crossed very low subs have some harmonic distortion - these frequencies can be perceived. But this an added artifact.

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.

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.