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Time aligned speakers - do they make sense?

Digital_Thor

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Too bad your tech friend hung out with the wrong crowd :) ... here in the states you can literally enjoy any type of food from around the world at a local neighborhood restaurant in just about any city.
Yup... he was a Greek tech, who told me that he had to move from Greece to Germany to find a serious job. I don't even have to make this stuff up myself.... people bring it to me ;)
I know that there is great food everywhere - if you look. Same here in Denmark, but we also have the type of food for a given crowd, closest to where that crowd hang out - relevant to what they want to pay. I can see a Michelin restaurant from my apartment... but I never went there.... but my boss did.
I fairly believe that he might just encountered the fact, that in a huge industrial area, at some maybe late hour... it can be difficult to get something to eat - I admit, that his story did not provide that level of information.
 

Digital_Thor

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Sorry Denmark,
Your European perspective of America's culinary offerings sound to be jaundiced.
FULL STOP!
My mom moved to LA in the 60's and had my half-brother, which I love just like my "full" sister. And the stories are pretty straight up, fitting with what you see and hear in the media. I guess history is repeating and that most cultures have their things sticking pretty well, for quite some time, making up our identity, if you will. Look at us Danes.... we are still vikings, like Americans are cowboys. Guess tv and movies did their trick :p
Nothing is black and white, but funnily enough, my new colleague, who just moved in from New York, a few months ago.... brings up stories that fit so damn well... that it's almost scary. My other colleague, who worked in a restaurant in the US, confirm several stories too, while his dad gave Wall Street a go.... still trying... and that is a rough story all by itself.
Nothing is perfect.... we could easily turn the story upside down with someone moving from Denmark. But I believe it's like speakers.... there are compromises - but there are also clear trends. Some of my absolute favorite comedians, like George Carlin, Bill Burr, Christopher Titus and more, joked about all of this, for years.
If our tiny country can admit that we have our faults, then hopefully your huge country, can admit that there's maybe a bit of dust and mold in the corners ;)

But I'm sorry for letting myself getting carried away - I will try and stay on the subject :)
 

Digital_Thor

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My understanding is that Earl's subs are bandpass subs, so their top end has a built-in third order lowpass function before any additional filtering.

My experience with distributed multisub systems has been that it's a good idea to aggressively roll off the top end of any subs that are positioned well away from the main speakers (like alongside or behind the listening area), so they don't betray their locations by passing audible upper bass/lower midrange energy. I use a 4th order lowpass filter, and my understanding is that that's what Earl uses as well (3rd order acoustic lowpass + 1st order electrical lowpass).
Now... that's interesting. I use a fourth order on my 4 subs too, and seem to get pretty nice results, when merely following his advice, on having the mains with no high-pass, or at least a first order. So I have a first order on my mains at 60Hz, then a different cross-over point for each sub, but with high enough filter, for them not to be localized. Now, when I measure in the seated position, there only seem to be variance around the area where my subs cross - when I move the mic half a meter around where I usually sit.
Another thing. I find it to be more balanced, with woofers that are minimum 8", when combining them with subwoofers that are 12" and 15". The overall impact and SPL seems more balanced this way. Tried with 6,5" woofers, since they only have to play down to 60Hz.... but I can't make it work like with bigger woofers.
 

Holmz

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I know that there is great food everywhere - if you look. Same here in Denmark...

Actually had one of the best steaks in Amsterdam.
The Noma place in Copenhagen is supposedly worth getting the snout into the trough at.
 

Dougey_Jones

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My mom moved to LA in the 60's and had my half-brother, which I love just like my "full" sister. And the stories are pretty straight up, fitting with what you see and hear in the media. I guess history is repeating and that most cultures have their things sticking pretty well, for quite some time, making up our identity, if you will. Look at us Danes.... we are still vikings, like Americans are cowboys. Guess tv and movies did their trick :p
Nothing is black and white, but funnily enough, my new colleague, who just moved in from New York, a few months ago.... brings up stories that fit so damn well... that it's almost scary. My other colleague, who worked in a restaurant in the US, confirm several stories too, while his dad gave Wall Street a go.... still trying... and that is a rough story all by itself.
Nothing is perfect.... we could easily turn the story upside down with someone moving from Denmark. But I believe it's like speakers.... there are compromises - but there are also clear trends. Some of my absolute favorite comedians, like George Carlin, Bill Burr, Christopher Titus and more, joked about all of this, for years.
If our tiny country can admit that we have our faults, then hopefully your huge country, can admit that there's maybe a bit of dust and mold in the corners ;)

But I'm sorry for letting myself getting carried away - I will try and stay on the subject :)
There’s plenty wrong with the good ol’ US of A, that we’re all able to be here together enjoying this hobby together is what matters. Not to get too political, but, I’ve been greatly heartened to see how quickly the world has circled the wagons around Ukraine and rejected naked aggression. Excited to welcome new Nordic friends to NATO and reject whatever this ideology is that Russia seems to be pushing.
 

dualazmak

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Now... that's interesting. I use a fourth order on my 4 subs too, and seem to get pretty nice results, when merely following his advice, on having the mains with no high-pass, or at least a first order. So I have a first order on my mains at 60Hz, then a different cross-over point for each sub, but with high enough filter, for them not to be localized. Now, when I measure in the seated position, there only seem to be variance around the area where my subs cross - when I move the mic half a meter around where I usually sit.
Another thing. I find it to be more balanced, with woofers that are minimum 8", when combining them with subwoofers that are 12" and 15". The overall impact and SPL seems more balanced this way. Tried with 6,5" woofers, since they only have to play down to 60Hz.... but I can't make it work like with bigger woofers.

Interesting...

Just for our reference, using 8-wave, 3-wave and single-wave tone burst signals, we can rather easily objectively measure as well as objectively visualize (using Adobe Audition) and objectively adjust time alignment between subs and woofers, cleanliness and tightness of the sound given by subs, woofers and most importantly subs+woofers at the overlapped Fq zone. (I have done these recently. See my post #86 on this thread.)

You wrote "when I measure in the seated position...". Did you use tone burst signals and visual analysis tools like Adobe Audition?

This type of objective measurements and adjustments are also very much useful for determination of the XO frequency and selection of XO filter slopes.

Of course, any of objective/subjective tuning on our audio system should be finally evaluated by careful subjective listening sessions at our listening position in our listening environments, though.
 
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gnarly

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Interesting...

Just for our reference, using 8-wave, 3-wave and single-wave tone burst signals, we can rather easily objectively measure as well as objectively visualize (using Adobe Audition) and objectively adjust time alignment between subs and woofers, cleanliness and tightness of the sound given by subs, woofers and most importantly subs+woofers at the overlapped Fq zone. (I have done these recently.)

Hi dualazmak,

First let me say I've enjoyed reading your project links you posted in #86 of this thread. That's the most extensive use of wavelet bursts for timing, that I've seen. Nice effort you put in sharing that.

I've been using ARTA to study the use of wavelets for timing. It has a built-in storage o'scope that makes captures and comparisons pretty easy.
Also use REW's scope which has really nice graphical capability, but alas no storage facility.

Here's a recent example of tuning a speaker and then checking it with wavelet bursts that might be of interest (to those who think time-alignment is valuable ;))

Speaker is the same 4-way main i posted about on first page of this thread.
In place were a 120Hz high pass, and xovers at 300Hz, 750Hz, and 6.3kHz. All those were linear phase 96dB/oct LR.
The speaker was tuned/timed to about 1m using the conventional technique of matching frequency response to a target curve. Target being Flat mag and phase....
here's the acoustic mag and phase measurement.
syn9t spot tune for burst.JPG



Ok, then to see how well wavelets looked for a "near perfectly tuned" speaker, I ran 1.5 cycle bursts at various frequencies to check how well their time alignments held up.

One immediate pleasant surprise was how extraordinarily clean the microphone captured, acoustic wavelet captures looked.
So I tuned off the FIR processing for each driver and compared, and wavelet captures clearly degraded, ranging from a little to a lot, depending on where in the driver's passband i was testing.
Anyway, that's not the point of this post....I'm just trying to explain how the next set of captures can look so good...like pure electrical, not acoustic.
It's simply the power of FIR to a spot, which will obviously degrade some off the spot (but not nearly as much as folks seem to think, ime.)

back to topic....how do the wavelet bursts time align...
Here are comparisons of 150Hz to various frequencies, 300Hz, 700Hz, 2000Hz, and 6.3kHz....in order.
Note the time cursor is locked at 178ms on all.
arta spot burst 150 Hz & 300Hz.JPG

arta spot burst 150 Hz & 700Hz.JPG

arta spot burst 150 Hz & 2000 Hz.JPG

arta spot burst 150 Hz & 6300Hz.JPG


It's pretty clear to me that flat mag and phase produce excellent wavelets with spot-on timing.
They are equivalencies imo, just like perfect mag and phase, equals perfect impulse, step, and square waves...etc


Of course, any of objective/subjective tuning on our audio system should be finally evaluated by careful subjective listening sessions at our listening position in our listening environments, though.
Absolutely agree. After all, in the end it's all about pleasing the ears, huh? :)

I think if more folks could hear speakers with precise time alignment (which again for me is flat mag and phase), they might change their minds about its audibility.
 

Digital_Thor

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Hi dualazmak,

First let me say I've enjoyed reading your project links you posted in #86 of this thread. That's the most extensive use of wavelet bursts for timing, that I've seen. Nice effort you put in sharing that.

I've been using ARTA to study the use of wavelets for timing. It has a built-in storage o'scope that makes captures and comparisons pretty easy.
Also use REW's scope which has really nice graphical capability, but alas no storage facility.

Here's a recent example of tuning a speaker and then checking it with wavelet bursts that might be of interest (to those who think time-alignment is valuable ;))

Speaker is the same 4-way main i posted about on first page of this thread.
In place were a 120Hz high pass, and xovers at 300Hz, 750Hz, and 6.3kHz. All those were linear phase 96dB/oct LR.
The speaker was tuned/timed to about 1m using the conventional technique of matching frequency response to a target curve. Target being Flat mag and phase....
here's the acoustic mag and phase measurement.
View attachment 208202


Ok, then to see how well wavelets looked for a "near perfectly tuned" speaker, I ran 1.5 cycle bursts at various frequencies to check how well their time alignments held up.

One immediate pleasant surprise was how extraordinarily clean the microphone captured, acoustic wavelet captures looked.
So I tuned off the FIR processing for each driver and compared, and wavelet captures clearly degraded, ranging from a little to a lot, depending on where in the driver's passband i was testing.
Anyway, that's not the point of this post....I'm just trying to explain how the next set of captures can look so good...like pure electrical, not acoustic.
It's simply the power of FIR to a spot, which will obviously degrade some off the spot (but not nearly as much as folks seem to think, ime.)

back to topic....how do the wavelet bursts time align...
Here are comparisons of 150Hz to various frequencies, 300Hz, 700Hz, 2000Hz, and 6.3kHz....in order.
Note the time cursor is locked at 178ms on all.
View attachment 208205
View attachment 208206
View attachment 208207
View attachment 208210

It's pretty clear to me that flat mag and phase produce excellent wavelets with spot-on timing.
They are equivalencies imo, just like perfect mag and phase, equals perfect impulse, step, and square waves...etc



Absolutely agree. After all, in the end it's all about pleasing the ears, huh? :)

I think if more folks could hear speakers with precise time alignment (which again for me is flat mag and phase), they might change their minds about its audibility.
I'm curious... how do your speakers measure off-axis - relative to on-axis?
 

gnarly

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I'm curious... how do your speakers measure off-axis - relative to on-axis?
Sure. here's same speaker with some horiz measurements made indoors 0-10-20 degrees.
Which gives a fairly generous 40 degree wide listening area.
Tuning was for optimizing 0-20 degs, not trying to be perfect to a spot like for the wavelet tests in my prior posts.

syn10 indoor polars 0-20 H 10deg V.JPG


I don't really like or trust polars made indoors, as i think best measurements are far-field and without gating.... which for me requires outdoors....and at >3m.

Hopefully, I'll be outside soon, putting together a more extensive set of off-axis measurements.....
 

ernestcarl

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My understanding is that Earl's subs are bandpass subs, so their top end has a built-in third order lowpass function before any additional filtering.

My experience with distributed multisub systems has been that it's a good idea to aggressively roll off the top end of any subs that are positioned well away from the main speakers (like alongside or behind the listening area), so they don't betray their locations by passing audible upper bass/lower midrange energy. I use a 4th order lowpass filter, and my understanding is that that's what Earl uses as well (3rd order acoustic lowpass + 1st order electrical lowpass).

Yes, I think you're right... though, he did not specifically mention the "bandpass" design of his subs in the video I watched him discuss it.
 

dualazmak

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I'm curious... how do your speakers measure off-axis - relative to on-axis?

My strategy/policy on possible (or impossible?) off-axis measurement in my mulitchannel multi-driver multi-way multi-amplifier stereo setup is almost identical to @gnarly's above approach; for satisfactory off-axis measurements, I believe that I need to bring my entire system into anechoic chamber or move to wide open outside field those would be unrealistic at all.

Consequently, I always dare to limit myself to quasi-on-axis measurements at the listening position in my actual room environments.

I am always interested in some improvement(s) of the total sound quality at my listening position in my listening environment, as @Purité Audio (keith) simply and kindly wrote here; "You must hear equipment in your own room in your own system, compare unsighted if there isn’t an immediately apparent difference/improvement. To go further if there isn’t a significant improvement then don’t change anything, the largest gains are speakers and room."
 
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Frgirard

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My strategy/policy on possible (or impossible?) off-axis measurement in my mulitchannel multi-driver multi-way multi-amplifier stereo setup is almost identical to @gnarly's above approach; for satisfactory off-axis measurements, I believe that I need to bring my entire system into anechoic chamber or move to wide open outside field those would be unrealistic at all.

Consequently, I always dare to limit myself to quasi-on-axis measurements at the listening position in my actual room environments.

I am always interested in some improvement(s) of the total sound quality at my listening position in my listening environment, as @Purité Audio (keith) simply and kindly wrote here; "You must hear equipment in your own room in your own system, compare unsighted if there isn’t an immediately apparent difference/improvement. To go further if there isn’t a significant improvement then don’t change anything, the largest gains are speakers and room."
The ground plane measurement on a parking
 

dualazmak

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Of course, any of objective/subjective tuning on our audio system should be finally evaluated by careful subjective listening sessions at our listening position in our listening environments, though.

I recently started the still-ongoing "post series", therefore, here and thereafter entitled "Excellent Recording Quality Music Albums/Tracks for Subjective (and Possibly Objective) Test/Check/Tuning of Multichannel Multi-Driver Multi-Way Multi-Amplifier Time-Aligned Active Stereo Audio System and Room Acoustics; at least a Portion and/or One Track being Analyzed by Color Spectrum of Adobe Audition in Common Parameters" (sorry for rather long tile) .

Your visits and participations will be highly appreciated.
 
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