For grins here is one APL_TDA plot.
Its not a living room but a hobby room in cellar full of spread out furniture and strange tools standing all over place and no room treatment at all. Speaker is FAST system 10F/8424 with 10 inch German Kevlar woofer and XO is LR 8th order linear phase at 355Hz. With both L and R channel from stereo track routet to same speaker while it sound fantastic with nose on axis at 0,3 meter will take some huge work and care to get anywhere bit near to what acoustic performance wesayso show.
Its not a living room but a hobby room in cellar full of spread out furniture and strange tools standing all over place and no room treatment at all. Speaker is FAST system 10F/8424 with 10 inch German Kevlar woofer and XO is LR 8th order linear phase at 355Hz. With both L and R channel from stereo track routet to same speaker while it sound fantastic with nose on axis at 0,3 meter will take some huge work and care to get anywhere bit near to what acoustic performance wesayso show.
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ra7, the reason is simple, what do the distributed subs do? They smooth out the overall frequency because of their independent positions.
Now look at the line array again. They smooth out the frequency because of their independent positions. Even Geddes said to put some subs higher, and it will help.
Basically it isn't a point source, it's 25 mini subs hammering away, each with their own setbacks due to their individual position, however summing to a smoother total.
Of course you can do time alignment on the subs. But the arrays are in a fixed left and right position that does not change much when you move. A near placed sub would get louder once you move toward it.
I do not have anything against a multi sub solution, it makes perfect sense. Even better with different subs playing different parts they excel at. Like my right speaker works harder at 60 Hz, while my left one does 30 Hz better due to it's specific placement.
How much are you going to hear in the graphs getting better? That's what I wanted to learn. That's why I did what I did.
I've said it more than once. I've heard both a time aligned and a non time aligned setup.
Not blind, I admit. But all you have to do is watch the feet of visitors.
I've had it completely linear out to DC so to speak, a big change in phase. But a lot of material felt out of place. I live with each setting for more than a couple of days to notice how I "feel" about it. The flat phase down to DC wasn't right. Probably because the bass came in soon on some recordings. Following the band passed nature of the FR response is the best compromise I have found.
Have you heard a setup measuring like this? I have lived without that linearity for a long time. I enjoyed that time, no doubt. But think of it as more "relaxed" as that's what it is.
We are used to that, but you CAN train yourself to notice a difference. Listen to the real sounds around you. They won't have a group delay at lower frequencies. Study that sound. Record it and play it back.
Sure there are limits to what you can hear. But once the simplest of instruments used in mixes, placed in front of you due to excellent imaging have lower body due to the harmonics lining up, you too will hear that difference.
An exiting difference (said that a million times too). Not as huge as getting the frequency curve sorted out between left and right. But it helps to eliminate your room and bring you closer to a believable stage. As does low frequency extension.
We've done this back and forth a million times. Why is it so hard to believe a measurable difference can really be perceived as a difference. Do that APL plot. (even said that before)
It might scare you how that looks at the listening position.
One more thing, I never used APL_TDA to clean up my measurements. I only used every TAB in REW. I had to hunt down what I was looking for. The APL plot was just me running that demo. I wish I had it available when I was fighting my room. I know were every ripple in that plot comes from, bizarre right? I was devoted to it to keep my sanity in one of the lesser periods in my life. Just to learn.
BYRTT, did you notice a difference? Did it sound different to you?
Now look at the line array again. They smooth out the frequency because of their independent positions. Even Geddes said to put some subs higher, and it will help.
Basically it isn't a point source, it's 25 mini subs hammering away, each with their own setbacks due to their individual position, however summing to a smoother total.
Of course you can do time alignment on the subs. But the arrays are in a fixed left and right position that does not change much when you move. A near placed sub would get louder once you move toward it.
I do not have anything against a multi sub solution, it makes perfect sense. Even better with different subs playing different parts they excel at. Like my right speaker works harder at 60 Hz, while my left one does 30 Hz better due to it's specific placement.
How much are you going to hear in the graphs getting better? That's what I wanted to learn. That's why I did what I did.
I've said it more than once. I've heard both a time aligned and a non time aligned setup.
Not blind, I admit. But all you have to do is watch the feet of visitors.
I've had it completely linear out to DC so to speak, a big change in phase. But a lot of material felt out of place. I live with each setting for more than a couple of days to notice how I "feel" about it. The flat phase down to DC wasn't right. Probably because the bass came in soon on some recordings. Following the band passed nature of the FR response is the best compromise I have found.
Have you heard a setup measuring like this? I have lived without that linearity for a long time. I enjoyed that time, no doubt. But think of it as more "relaxed" as that's what it is.
We are used to that, but you CAN train yourself to notice a difference. Listen to the real sounds around you. They won't have a group delay at lower frequencies. Study that sound. Record it and play it back.
Sure there are limits to what you can hear. But once the simplest of instruments used in mixes, placed in front of you due to excellent imaging have lower body due to the harmonics lining up, you too will hear that difference.
An exiting difference (said that a million times too). Not as huge as getting the frequency curve sorted out between left and right. But it helps to eliminate your room and bring you closer to a believable stage. As does low frequency extension.
We've done this back and forth a million times. Why is it so hard to believe a measurable difference can really be perceived as a difference. Do that APL plot. (even said that before)
It might scare you how that looks at the listening position.
One more thing, I never used APL_TDA to clean up my measurements. I only used every TAB in REW. I had to hunt down what I was looking for. The APL plot was just me running that demo. I wish I had it available when I was fighting my room. I know were every ripple in that plot comes from, bizarre right? I was devoted to it to keep my sanity in one of the lesser periods in my life. Just to learn.
BYRTT, did you notice a difference? Did it sound different to you?
Sure, no problem. I'll add this: it was way easier to hear how wrong my linear phase out to DC was than to determine the difference of phase going in the more usual relaxed direction. It sounded off.(*) No other words come to mind.
It's not a listen only thing, you feel the notes, once the rhythm locks in over a wider area it moves you. Getting it wrong is way easier than getting it right.
You cannot adjust phase and expect it to work out. It's not that simple, sadly.
To get it to click took me a mighty long time, judging a group of 50 very different songs over and over again.
(*) Especially noticeable on the bass in Anne Bison - September.... That was a really small change in milliseconds, relatively speaking. A way different experience.
It does mean to me we don't want the bass to arrive early. Dragging it a little late is always the better/saver choice. It's also way more clean sounding with great harmonic structures in, say acoustic guitar... they do have lower harmonics and sound more full with everything in line.
Listening to a simple a triangle like sound while feeling it (in sync) on your eyelid. that's the subtle queues you're looking for.
(one of the songs, I guess Pink Froid on Infected Mushroom's Converting Vegetarians II)
It's like there's more power behind notes.
One more thing: when I did do the APL demo, out at the listening spot, I did make a little dance of joy. Finally a visual representation/confirmation of what I looked for (and achieved), for months, in REW.
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I've added a post in the Convolution Thread showing the impact of room treatments and DRC with the help of some TDA graphics.
Didn't want to veer too far away from the Towers, Ron's room and the subwoofers discussion.
http://www.diyaudio.com/forums/full...eaker-correction-networks-33.html#post4925086
Didn't want to veer too far away from the Towers, Ron's room and the subwoofers discussion.
http://www.diyaudio.com/forums/full...eaker-correction-networks-33.html#post4925086
I always meant to do a 3D sketch, never got around to actually do it.
ra7, did you catch the discussion in the RePhase thread about beam forming and averaging? Starting at: http://www.diyaudio.com/forums/multi-way/221434-rephase-loudspeaker-phase-linearization-eq-fir-filtering-tool-141.html#post4920173
Same principles really. And the real reason why array's are less likely to excite floor and ceiling reflections. Vertical surface reflections still happen from big vertical areas, that's why I use damping on those. Due to the array nature all of the other stuff found in a normal room has a less severe impact.
Basically averaging the response of all the separate drivers is the key why each individual reflection has less impact. Except when it's coming from surfaces as large as the array and in the same direction. This is the big plus, out to lower frequencies. It does not take away all of it, that's why I'm considering adding subs. For both headroom and balancing each channel so the other channel does not have to do that job. It is likely the sub will introduce it's own problems, as it will be more placement dependant. It sits beside the towers, making it likely it won't excite the room in the same way the arrays do, thus I can use both to hopefully level the problem area's out by averaging those two (one sub plus one array on each side).
Maybe a pyramid shape in the low end would be most ideal
. That would vary horizontal and vertical distances to objects.I'd tend to agree that a bass array approach would produce better results than a distributed sub system simply by using Geddes own logic to his approach in that more phase interactions smooth peaks and nulls by cancellations. Fluid dynamics and wave propagation will clearly show the more sources generating at near equandestant locations, the more uniform the overall wavefront.........use enough drivers and the end result would be near to one giant driver pulsing on a horizontal plane. Had Wesayso's arrays been a true two way with 6" woofers with more excursion and an Fs of 30hz, the topic would be even less debatable and more self evident in his and others listening impressions. It's also important to consider Earls approach taylors towards the Home Theater enthusiast as well where sub 30hz content is a HUGE part of the equation.
So in reality, adding two stereo subs to augment the bass response of the existing arrays might just be a step backwards as the wavefront is no longer uniform and will not excite the room evenly without extreme DSP and servo control. The 'logical' solution to adding more LF extension would be two more bass only arrays in the rear of the room where the two opposing wavefronts would combine at the listening position.........not exactly a practical approach or very ergonomically responsible!.........but nothing in this hobby ever is.
Even convincing the missus to allow for two front corner loaded bass arrays using larger drivers would be better than two small stand alone subs. Solves the problem of corner resonances created by the current placement of the full range arrays.
So in reality, adding two stereo subs to augment the bass response of the existing arrays might just be a step backwards as the wavefront is no longer uniform and will not excite the room evenly without extreme DSP and servo control. The 'logical' solution to adding more LF extension would be two more bass only arrays in the rear of the room where the two opposing wavefronts would combine at the listening position.........not exactly a practical approach or very ergonomically responsible!.........but nothing in this hobby ever is.
Even convincing the missus to allow for two front corner loaded bass arrays using larger drivers would be better than two small stand alone subs. Solves the problem of corner resonances created by the current placement of the full range arrays.
Thanks Wesayso for pointing to the discussion in the Rephase thread. Seems interesting. I am reading the papers!!
The bass array will definitely help with the floor/ceiling mode and to smooth out some other higher order modes. The left and right speaker will also help with the mode across the room. Maybe just a single sub near your listening spot can help manage the front to back mode. You can model it in REW. I used it to site the subs in my room.
The bass array will definitely help with the floor/ceiling mode and to smooth out some other higher order modes. The left and right speaker will also help with the mode across the room. Maybe just a single sub near your listening spot can help manage the front to back mode. You can model it in REW. I used it to site the subs in my room.
There's not much to wish for except lowering the needed boosts in the low end.
I simply don't have space for a sub near the listening space. I was planning 3 subs a long time ago but that was before I heard what these tiny drivers can do.
I'm restricted. And I do take that very seriously. I consider myself lucky to have had the support to be able to do what I have done so far. Not all spouses would show this level of WAF. 2 Huge towers, 3 even bigger damping panels. Not to mention the hours spend on it all. It was a once in a life time opportunity for me to build, learn and enjoy.
If there was more of an entrepreneur in me I would have pursued a career in it. This is what I love to do. Right now I'm glad I can use this experience positively in my new job.
I simply don't have space for a sub near the listening space. I was planning 3 subs a long time ago but that was before I heard what these tiny drivers can do.
I'm restricted. And I do take that very seriously. I consider myself lucky to have had the support to be able to do what I have done so far. Not all spouses would show this level of WAF. 2 Huge towers, 3 even bigger damping panels. Not to mention the hours spend on it all. It was a once in a life time opportunity for me to build, learn and enjoy.
If there was more of an entrepreneur in me I would have pursued a career in it. This is what I love to do. Right now I'm glad I can use this experience positively in my new job.
Nope
When I was a little boy I dreamt about having a house where the speakers would be placed in wall with a corridor as the enclosure. Must have been when I was about 11 years old.
Most are sure those milk carton format speakers are enough.
I was lucky to move in together and keep my set of ~0.7m x 0.7m x 1.3m speakers.
Especially after comparing those to her own set, which was at least 3x the milk carton size. She never expected I could outperform those big speakers with the arrays. We won a lot of floor space.
I was lucky to move in together and keep my set of ~0.7m x 0.7m x 1.3m speakers.
Especially after comparing those to her own set, which was at least 3x the milk carton size. She never expected I could outperform those big speakers with the arrays. We won a lot of floor space.
