Using multiple sets of speakers for stereo?

[dzerig]

This is a question mostly for theory. What if we ran all the speakers reviewed by Amir at the same time?

The benefit being that they offset their colorations and, the more speakers you install, the greater the trend towards neutral.

Again, not for practice, just in theory, would having many sets of different speakers work this way?

 

[a2Thompson]

Ok. Not sure this is the same thing, but i have been working on my kitchen/dining room/living room area to get excellent sound dispersed throughout. I’m at 6 speakers currently and after once I worked out some phase issues it is sounding great. I think precisely because once I get off axis and the highs drop off another speaker is there to fill them in. So most main locations now have a much more balanced FR. Eventually I’ll post some REW curves.

 

[fpitas]

This is a question mostly for theory. What if we ran all the speakers reviewed by Amir at the same time?

The benefit being that they offset their colorations and, the more speakers you install, the greater the trend towards neutral.

Again, not for practice, just in theory, would having many sets of different speakers work this way?

All the weird dips and peaks caused by interference may be the downfall of this scheme.

 

[Deleted member 21219]

This is a question mostly for theory. What if we ran all the speakers reviewed by Amir at the same time?

The benefit being that they offset their colorations and, the more speakers you install, the greater the trend towards neutral.

Again, not for practice, just in theory, would having many sets of different speakers work this way?

About 50 years ago, some friends of mine tried something like this.
They sat quite a few speakers up, one atop the other, on the left and on the right. They were driven by a Crown DC300, which was new at the time and lauded as something fantastic. The series/parallel hookup was done by a friend who worked at the local radio station, since many did not have adequate mastery of Ohm's Law to figure out how to hook them all up.

The sound was full of comb filtering from interference nodes, and was very "muddled". Correctly or incorrectly, it was concluded that the differing distances of each speaker from the listener's position was responsible for this, and the speakers were arranged in an arc, with lower ones shimmed to aim up and the ones on top shimmed to aim down.

That improved things somewhat, but not a great deal.

The result was mostly midrange and upper bass, with no deep bass, and erratic treble results. This was (ostensibly) the result of most speaker systems having greater headroom in the upper bass and midrange compared to the deeper bass, and treble units (especially at that time) beaming terribly. I'm not sure this conclusion was 100% accurate.

Basically, it was a mess. 'Neutral" was not an apt description. It gave everyone an appreciation for the professional expertise of commercial sound engineers, though.

Jim

 

[DJNX]

No. Overlapping of point source speakers always results in comb filtering.

Comb filtering occurs when certain frequencies are either amplified or attenuated by the superposition of a delayed version of the original audio signal onto itself. In addition, in order for this comb filtering effect to happen, the level of the signals must be within 10 dB from each other. The resulting frequency response curve of a comb filter consists of a series of regularly spaced notches, giving the appearance of a comb for the hair.

This superposition leads to certain cancellations and amplifications in the audio spectrum that in turn produce a subjectively metallic sound. Voices sound harsh and sharp due to significant parts of their fundamental frequency range being absent.

Comb filters become particularly disturbing when they change over time, as it can happen when the sound source (e.g. a musician/instrument) or the microphone moves during the performance or recording process. As a result, the first reflections are continuously changing and the comb filter in turn migrates across the audio spectrum. This overall time-varying attenuation and amplification of different frequencies is called ‘phasing’.

What is Comb Filtering and how to avoid it - Live Sound

Comb filtering occurs when certain frequencies are either amplified or attenuated by the superposition of a delayed version of the original audio signal onto itself.

blogs.qsc.com

 

[DVDdoug]

So... This will not work but if it did you'd get an average... Better than than the worst speaker and worse than the best speaker.

You should be able to get more total bass output with all of the woofers working together. But the bass would roll-off faster (with the deep bass weaker than the mid-bass) because there will be one speaker with the deepest bass and the other speakers will detract from that.


P.S
With different speakers, the interference/cancelation will be WORSE than "typical comb filtering". The crossover network introduces phase shifts and to get a smooth transition and put the drivers back in-phase at the crossover frequency, the tweeter in a 2-way, or the midrange in a 3-way, is often wired in reverse. So the tweeter in a 2-way may be 180 degrees out-of-phase with the tweeter in a 3-way. And it becomes more of a mess with different speakers having different crossover frequencies - You might have two 3-way speakers with the midranges in-phase with each other, but with different crossover frequencies you might have a sound coming from the midrange in one speaker and the same sound coming from the tweeter in the other.

 

[Deleted member 21219]

With different speakers, the interference/cancelation will be WORSE than "typical comb filtering". The crossover network introduces phase shifts and to get a smooth transition and put the drivers back in-phase at the crossover frequency, the tweeter in a 2-way, or the midrange in a 3-way, is often wired in reverse. So the tweeter in a 2-way may be 180 degrees out-of-phase with the tweeter in a 3-way. And it becomes more of a mess with different speakers having different crossover frequencies - You might have two 3-way speakers with the midranges in-phase with each other, but with different crossover frequencies you might have a sound coming from the midrange in one speaker and the same sound coming from the tweeter in the other.

Thank you! This is an excellent explanation for what we heard.

Jim

 

[fpitas]

It's a pity it can't work IRL. Frat houses would have the best sound ever!

 

[NTK]

The site below will let you visualize sound wave interferences from multiple sources. Use the drop down menu to add sources and/or other items. Use the mouse to left click and drag the sources to move them.

https://falstad.com/ripple/

 

[MaxwellsEq]

For stereo, including the task of generating the soundstage image, the best approach is to get two speakers only working optimally in the room. All other approaches lead to compromises which are worse than the benefits.