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Time alignment and imaging

PROJECT 2501

PROJECT 2501

Active Member
Ever since picking up a pair of technics sb-7000a speakers I've completely dismissed other speaker designs that utilize a flat baffle or non mirrored driver configuration. Up until my acquisition of the technics speakers I had never experienced stereo imaging. I had heard of it and read lengthy descriptions about it and was under the impression I knew what it was but ultimately I was completely clueless about the phenomenon up until my first personal experience with it. Listening to music was no longer something I did using only my ears. It now was something I could see with my eyes and experience through other humanly senses beyond auditory.
Now that I know there is more to stereo music than just hearing the sounds and that there are speakers that provide the ability to actually see the music in a three dimensional space I am unable to do any serious listening on any audio system that fails to provide an imaging effect.
My question here today is one regarding the main characteristics of a speaker design and what specifically is responsible for a speakers ability to provide that strange, trippy, and mind blowing effect of stereo imaging. Does it come down to driver configuration? Complicated crossover design? Time alignment using either an electronic delay or physically aligning the voice coils on either a stepped or angled baffle design?
Or perhaps a well balanced combination of these designs and other contributing factors beyond my understanding?
The reason for my interest in finding the answers to these questions is because I want to know if an improved stereo image is something that could be achieved through a modified version of klipsch heresy speakers. I have a pair that's collecting dust and I wanted to know if a time alignment of the drivers with a modified cabinet would be worth the trouble and produce the results that I am looking for..

Please feel free to add anything else that you feel is relevant to the imaging phenomenon of loudspeakers especially if it has to do with modifications of existing speaker as to improve its imaging.
Thanks
 
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that would take a lot of measurements in an aechoic chamber to get right, you could try different combinations by ear but that sounds like a lot of work that won't pay off.
 
Congrats!! It sounds like you finally have a set of speakers you like. Just dont dismiss the flat baffle design, lots of them image very well. I would personally consider those the best speakers technics ever built. What would be say your next favorite set of speakers is? I'm just curious what you have been listening to before you realized what imaging really is.
 
I looked into this years ago. What I know is, it's not as simple as lining up the driver voice coils. Crossovers have an effect on phase, so you'd have to be able to measure the output of each driver after the crossover and try to align it.

This is one of the many things that make me wonder if the future of high end audio is digital powered speakers with separate amps for each driver. In the digital world, I would think it would be relatively easy to phase align everything.
 
sansuibutch said:
Congrats!! It sounds like you finally have a set of speakers you like. Just dont dismiss the flat baffle design, lots of them image very well. I would personally consider those the best speakers technics ever built. What would be say your next favorite set of speakers is? I'm just curious what you have been listening to before you realized what imaging really is.
Click to expand...

Before the technics i was using a pair of jbl l100 and a pair of 4311wxa. I also owned cerwin vega R26s, beovox S45, quadraflex lab standard 1, and pioneer CS-66a
 
Fast.Eddie said:
I looked into this years ago. What I know is, it's not as simple as lining up the driver voice coils. Crossovers have an effect on phase, so you'd have to be able to measure the output of each driver after the crossover and try to align it.

This is one of the many things that make me wonder if the future of high end audio is digital powered speakers with separate amps for each driver. In the digital world, I would think it would be relatively easy to phase align everything.
Click to expand...

Thats what i was afraid of..
Thanks
 
Fast.Eddie said:
I looked into this years ago. What I know is, it's not as simple as lining up the driver voice coils. Crossovers have an effect on phase, so you'd have to be able to measure the output of each driver after the crossover and try to align it.

This is one of the many things that make me wonder if the future of high end audio is digital powered speakers with separate amps for each driver. In the digital world, I would think it would be relatively easy to phase align everything.
Click to expand...

About the klipsch heresy...

What is your opinion on creating a copy of the technics cabinet with its stepped baffle style design and using the components of a klipsch heresy inside of it?
Do you think it would offer any improvement over the oem cabinet? Or do you thibk it would be a waste of time and resources?
 
PROJECT 2501 said:
About the klipsch heresy...

What is your opinion on creating a copy of the technics cabinet with its stepped baffle style design and using the components of a klipsch heresy inside of it?
Do you think it would offer any improvement over the oem cabinet? Or do you thibk it would be a waste of time and resources?
Click to expand...

I'm far from an expert on phase alignment, and even less so on classic Klipsch speakers. So less of an opinion than random thoughts.

I don't know that the Heresy isn't already time aligned. I would think with the horn tweeter, the voice coils are already closer to a similar plane than a conventional dynamic speaker. It's possible that it could be tweaked to improve the phase, but I would think you're kind of shooting in the dark without some way to measure the phase of the two drivers in real time and adjust accordingly. Even then, you could get them in phase, but out of time. In other words, the wave forms could line up, but be a cycle, or many cycles off from one another.

I'd never discourage anyone from experimenting. A number of years ago I got kind of obsessed with creating a DIY version of a Polk SDA. I never built a full set of speakers based on what I learned, but I did a lot of experimenting with four midrange drivers. I learned a lot, and did recreate the SDA effect. It was kind of cool. So you might want to play with it. But my guess is, you'll end up scratching your head a lot trying to decide "does that sound better?"
 
PROJECT 2501 said:
...My question here today is one regarding the main characteristics of a speaker design and what specifically is responsible for a speakers ability to provide that strange, trippy, and mind blowing effect of stereo imaging. Does it come down to driver configuration? Complicated crossover design? Time alignment using either an electronic delay or physically aligning the voice coils on either a stepped or angled baffle design?
Or perhaps a well balanced combination of these designs and other contributing factors beyond my understanding?
Click to expand...

Speakers vary a lot in their ability to provide a three dimensional image, obviously. However, of paramount importance is placement of the pair in a given room. A properly sited mediocre-imaging speaker can sound much better than a poorly-placed superior model.

It does also seem that smaller, or narrower, speaker cabinets, are an easier job for the designer from which to wrest a good image.
 
Seldom is the voice coil the proper acoustic center of a driver or driver/horn combination.

However, their alignment in the vertical plane has made good marketing pitch for decades.

Good sales pitch with an added visual can be very effective in generating a belief. If you believe it, you will probably hear it. Matsushita(Panasonic, Technics) played their hand well with their linear phase mascot.

Psychoacoustics, and expectation bias play a much larger role than they're credited for in many cases.

Proceed with caution as empirical measurement may turn out to be kryptonite to some belief systems.
 
In a past life I designed speaker systems used in corporate jet aircraft entertainment systems. I learned a lot about what makes speakers image really well. It’s pretty much two things; creating the best impulse response you can and eliminating diffraction and reflections from the enclosures.

To do this, generally the drivers are physically positioned in a slanted or stepped baffle arrangement that places the center of radiation of the drivers in the same plane relative to the listener. Their crossovers are designed to have linear phase so that the signals going to each driver are aligned in time. In order to reduce diffraction from the enclosure, the baffle is usually tapered and the baffle footprint is small - thus favoring narrow speakers that are deep.

You can see these design philosophies played out in speakers from Wilson, TAD, Avalon Acoustics, etc.

That’s not to say that there are other methods and speakers that image well without following the above design philosophies. For example I have a pair of Proac Response 1sc speakers with flat baffles that image really well.

I think it would take some measurement equipment (I use a MLSSAA analyzer) speaker design savvy, and cabinet making expertise to figure out how to get a speaker not originally designed with imaging in mind to image correctly.
 
Paul Klipsch had little interest in time alignment and the distance between the acoustic centers of drivers varies wildly in some of the speakers he designed, especially those that used basshorns. Yet the LaScalas I owned in the 70s imaged nicely and did depth like nobody's business; sometimes the image stretched from my lap back into the front yard.

I think dispersion pattern has a big effect on imaging (IME using different pattern horns has a profound effect on imaging) and as W9TR mentioned ridding obstructions that cause diffraction and reflections. The deep edges around the baffles of older box speakers are likely a reason many of them don't open up a big image.
 
musichal said:
Speakers vary a lot in their ability to provide a three dimensional image, obviously. However, of paramount importance is placement of the pair in a given room. A properly sited mediocre-imaging speaker can sound much better than a poorly-placed superior model.

It does also seem that smaller, or narrower, speaker cabinets, are an easier job for the designer from which to wrest a good image.
Click to expand...
Proper placement is important. I have a pair of speakers about 7' apart laying on there side up about ear level with tweeters to the outside. Imaging is great. I hear sound coming from the corners of the room well past the speakers. I get plenty of depth too. And all from some pretty basic two way monkey coffins.
 
Spend a couple days exploring this site. https://www.linkwitzlab.com/

When it comes to getting stereo speakers to reveal the magic of the intent sound engineers have in their two channel recordings, I have found to do whatever Siegfried (RIP) says.

There are three related but separate discussions on this subject. One, getting the most out of an existing set of speakers in an existing room. Two, creating a set of speakers that get the most out of an existing room. Three, developing a set of speakers and developing a listening environment that gets the most out of a recorded source.

Solutions are quite different and can be in conflict with each other for each of these discussions.

Time alignment of different frequencies is certainly a major variable on each of these discussions but it is not as simple as driver placement in a cabinet. 90% of this effect is in control (or out of control) of the sound and recording engineer.

Although much of this is physics, of special note are Linkwitz’s observations on the major effects our ears and mind have on spacial recognition of sound.
 
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stoutblock said:
Spend a couple days exploring this site. https://www.linkwitzlab.com/

When it comes to getting stereo speakers to reveal the magic of the intent sound engineers have in their two channel recordings, I have found to do whatever Siegfried (RIP) says.

There are three related but separate discussions on this subject. One, getting the most out of an existing set of speakers in an existing room. Two, creating a set of speakers that get the most out of an existing room. Three, developing a set of speakers and developing a listening environment that gets the most out of a recorded source.

Solutions are quite different and can be in conflict with each other for each of these discussions.

Time alignment of different frequencies is certainly a major variable on each of these discussions but it is not as simple as driver placement in a cabinet. 90% of this effect is in control (or out of control) of the sound and recording engineer.

Although much of this is physics, of special note are Linkwitz’s observations on the major effects our ears and mind have on spacial recognition of sound.
Click to expand...

I’ve come to find that spatial cues in the recording are the doorway to image resolution and the gear/room acoustic behavior the key to unlock it.
 
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