Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums > LAB: The Classic Live Audio Board

Question about column/stick speaker design

(1/15) > >>

George Reiswig:
So I recently sat in with a band that was using the newer, largest Bose stick system, with all the sticks behind the band.  I was at least a little impressed with them, especially the lack of feedback and lack of need for monitors.

So I started looking for similar speakers that didn't cost as much, and tried out a Turbosound ip2000 "Inspire."  It sounds okay, but I noticed that the spectral balance changes with distance.  I expected that a little bit, because it basically has one tweeter at the very top of the stick, then 17 2" drivers below that.  But what surprised me was that it sounds to me like the 2" drivers are actually being run differently: the ones near the bottom of the stick seem to have a lower HPF on them, the ones above that cut off higher. 

So my question is whether that is bad design, or intentional?  Is it better to...
- have 17 drivers all trying to run as full-range as they can so the spectral pattern is consistent no matter how close you are, or

- have fewer drivers trying to cover the high frequencies because of the shorter wavelength at those frequencies?

Scott Holtzman:

--- Quote from: George Reiswig on September 07, 2016, 11:13:57 PM ---So I recently sat in with a band that was using the newer, largest Bose stick system, with all the sticks behind the band.  I was at least a little impressed with them, especially the lack of feedback and lack of need for monitors.

So I started looking for similar speakers that didn't cost as much, and tried out a Turbosound ip2000 "Inspire."  It sounds okay, but I noticed that the spectral balance changes with distance.  I expected that a little bit, because it basically has one tweeter at the very top of the stick, then 17 2" drivers below that.  But what surprised me was that it sounds to me like the 2" drivers are actually being run differently: the ones near the bottom of the stick seem to have a lower HPF on them, the ones above that cut off higher. 

So my question is whether that is bad design, or intentional?  Is it better to...
- have 17 drivers all trying to run as full-range as they can so the spectral pattern is consistent no matter how close you are, or

- have fewer drivers trying to cover the high frequencies because of the shorter wavelength at those frequencies?



--- End quote ---

I am sure you will get a better answer but it has to do with the spacing.  The drivers have to be a 1/4 wavelength I believe to couple.  At HF a 2" driver is too far apart and will create comb filtering due to the mismatch.

I have seen hi-fi speakers that have a parallel HF array, usually ribbons for the dispersion characteristics next to the "mid" frequency line array.   This works well sitting in the close field but probably not optimum for sound reinforcement hence the classic dull sound of all the column arrays.

In non technical terms even as a kid I always thought the Bose arrays, including the much vaunted 901's sounded like shit.  As a little kid I would argue with my parents friends trying to tell me how good they sounded.  I imagine it was fairly obnoxious, just like the sound of the speakers.

Robert Piascik:

--- Quote from: Scott Holtzman on September 08, 2016, 03:37:44 AM ---
I imagine (I) was fairly obnoxious, just like the sound of the speakers.


--- End quote ---

At least the speakers had a volume knob they could turn down...

😀😀😀

Ivan Beaver:

--- Quote from: George Reiswig on September 07, 2016, 11:13:57 PM ---

- have fewer drivers trying to cover the high frequencies because of the shorter wavelength at those frequencies?

--- End quote ---
The best and most pure approach is to have a single driver cover the intended bandwidth.

Beyond that, a cabinet that produces a single source (orientation) of sound is better than one that has sound coming from physically different places-resulting in different signal arrivals at your ear.

Once you start to have different signal arrivals, all sorts of other things start to come into play in what you hear and how it behaves.

Everything is a compromise, and most often the compromise is what people "think" they want-without understanding the real factors involved.

The biggest difference is what does it sound like at different places?  As you move around the coverage pattern-is the sound the same?

A fun "trick" to play with "column speakers" is to turn them on their sides and get up around ear height-give or take a foot or so.

No put in pink noise and walk from one end to the other.

Does it sound the same?  If not- you need to ask yourself "Is my audience hearing different things depending on where they are seated?"

Scott Helmke:
Those column/line speakers do have some specific uses, though I think (for the price) the "everybody has a Bose stick" solution isn't that great.

More drivers = more bass, which is generally considered good. With some speakers it's common to have say two same-size drivers for both bass and mids, but filter the mids out of one of the speakers. That's because you don't want the mids coming from two different places at the same time, causing comb filtering.  Because the bass has much longer wavelengths you can have multiple drivers without much comb filtering.

I've seen some column designs that do the same thing over the length of the column.

Navigation

[0] Message Index

[#] Next page

Go to full version