The making of: The Two Towers (a 25 driver Full Range line array)

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Assembly2subs2.jpg

As always, I'm never that easily pleased and want a bit more. Combining the above look with my build pictures just didn't seem right. So I made a new material to use in Inventor, one that does come a bit closer in color.

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submlv-1.jpg


I could make it even more accurate, but I think this matches fine and has that glossy look :).
 

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I think I completely covered the subwoofer build here: DIY-Subwoofers – Vandermill-Audio

I believe I have shared/provided enough information in there for anyone to build his/her own.
Now on to the arrays and processing. That will take me a while though.

I miss being able to sit down in the house, all by myself and listen to some tunes. This is a strange period we're in right now. I feel fortunate that I can still go out the door, doing my job, while the rest of my family has to stay indoors.

It's a small sacrifice to make if it saves others though. I hope we can concur this crazy virus that has such a hold over our entire world. :boggled:
 
Not to long ago I said I liked the Home Theatre setup I had better than the current Stereo mix. So yesterday i took the time to configure a setup based on two other configurations. May sound easy, I assure you it's not.
Many things can go wrong, but it worked.

Which means I don't think my latest 2 pass correction is working any better than what i did before it. Oh well...

It isn't easy to extract something that works right on all accounts. :hphones:
It usually takes me a while to get where I want to be. That last two step method was an attempt to do better, be quicker. I'm not convinced...
 
Over the weekend (I had extra days off) I have had a good long listening session. Just listening and having fun, no judging etc. :).

However, after that session I once again started wondering why Home Theatre does so well with my own shuffler version. Not the same as all experiments done in the phantom center thread, but based more on the original shuffler idea as presented in that first post.

With Home Theatre material we have a dedicated center channel. Something we do not have in Stereo. A stereo sum (L+R) is quite different from that real center.

Yet I do think there possibly is something to gain there, for use in Stereo. When applied with care to the mid part of a mid/side chain. I'll revisit this once again. Just to see what it does. I've done it before but I do each experiment at least twice to make sure I did not miss anything the first time around.

Don't expect great things soon. I still don't have many listening sessions by myself. I steal half an hour here, a few minutes there as I'm not alone in my home during these crazy times.
 
Here's the thread:
Fixing the Stereo Phantom Center

The paper linked in the second post is about improving the phantom center if used with Home Theatre (so for material with a dedicated center channel being played back without an actual center speaker). In this thread there were several experiments to find ways to improve the tonal differences in perception between a phantom center and left/right side panned content.

The usefulness of that paper when applied to Stereo remains to be seen. I've done several experiments myself, some discussed in that thread, others are buried within this thread.

Within Stereo we do not have the dedicated center stream, meaning there's always left/right 'side' info present in any kind of sum we make to define the phantom part. However for Home Theatre, when run without an actual center channel this paper is useful i.m.h.o. I run a variation of that technique for my own Home Theatre setup and it has improved intelligibility.

Disclaimer: if you don't have a setup with strongly reduced early reflections you may not recognise the tonal differences between the phantom center and side panned sounds. See Toole's work on this for reference.

So far I've been using some mid/side EQ as a result of my experiments that originated from that thread (I had been using a coarse version of that prior to the thread and optimised it settings based on info gathered within the period that thread was active. Some other line array users now use this same EQ scheme as it does improve listening pleasure. How much of this applies to anyone's setup depends largely on room/speaker setup. Personally I've tested it with a nearfield setup with monitor speakers and can confirm it works there too (the mid/side EQ, not the shuffler).

I'd like to give this shuffler another try within Stereo. Just to see if I missed something the first time around. I'm setup to be able to incorporate this relatively easy, it is the many ways, variables and choices that make a test like this pretty complicated.

All of the above has to do with cross talk combing with left/right speakers being picked up with our two ears, something that's an integral part of Stereo. As an end user we have the liberty to play with it though. Especially if it enhances the end user's enjoyment and listening pleasure.

I have tried:
- the shuffler
- the phase 'only' shuffler that came about in that thread
- cross talk cancelation (based on the work of Prof. Choueiri)
- mid/side EQ

Sorry, you only asked for a link :D
 
I have the DSP part setup for the next experiment, finished that yesterday. However I did not have any time to try it yet. Could be another week before I get a chance.

One thing I did change (in my last listening session) is alter the balance between subs and array. Letting the array do a little more lifting and subs down a few dB.
Big difference in perception. I'm glad I went with the idea of combining both for the bottom end. I do believe that makes a difference (in perception).

Added a couple of pages to the vandermill-audio.nl website and changed a couple of pictures. (amplification and subwoofers)
I would have liked to be listening to the arrays instead of working on that though. I miss not having regular listening sessions.

Working on ideas for the pré-amp too! Keeping busy to still have a feeling of making progress.
 
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Thanks, I appreciate the explanation.

Playing MCH HT material without a centre channel is not something I have bothered my tiny mind with. :)

I have an AVR for HT, so if I wanted to not have a centre speaker, I would tell it so and it would reallocate C to L and R. Exactly what algorithm it would use -- well, I may be foolish, but one does hope that the big AVR companies have a decent way of making it happen, since they sell some pretty expensive gear to people who expect competence.

In fact, there may be merit in examining what a good AVR does in that situation, e.g. make a test file with signal in C channel only, tell the AVR there is no C speaker, and measure what comes out of all the other channels.

cheers
 
The multi channel without having a center speaker wasn't the reason for the start of that thread.

Once one removes/absorbs early reflections and plays a stereo song, you can notice how the tonal balance differs between the side panned sounds and the center.

Now not everyone would try and do something like that. Most people wouldn't mess with the room at al. However, some of us are fanatic. I wanted to create a soundscape in my room that makes me believe I'm there, right there at the performance. That means all the queues that point towards my room should not be there, they detract from the higher goal. Well I know what Toole and others have written about it. But hey, this is my space, I can do what I want and know what I want to achieve :). Toole isn't the king here, I am... well up to a point. I do need to keep my girl happy too :D.

Thus, once we have removed early reflections, you're confronted with the reality of stereo cross talk. And the more we work around that cross talk, the more a 3 dimensional/holographic like presentation can be formed.

Now this is something that lots of people may have experienced in their own room without going that extra mile. However the early reflections we perceive create a space, actually they define our space. This means every song gets the same sauce applied to it. This isn't quite obvious, unless you take it away, remove it.

What this cross talk work-around does, together with the ambience channels still provides some kind of sauce, but it varies with each song played. As it is build up largely from the ingredients present within the song.

That's basically why I like it so much. It is like being transported (audibly not visually) to the actual performance, venue or the artificially created scene.
Very addictive in listening!

The virtual Home Theatre center channel I got out of this project is an added benefit. Not to be a downer but usually the mixing is rather basic in these AVR devises. They let the early reflections of the room of the end user take care of the rest. But if you don't have any, it will become obvious. :p
 
Thus, once we have removed early reflections, you're confronted with the reality of stereo cross talk. And the more we work around that cross talk, the more a 3 dimensional/holographic like presentation can be formed.


Don't you think that the sound engineer that created that two channel audio would have evaluated the dimensional/holographic presentation of that recording using 2 speakers that also have the same stereo cross talk. In other words a good stereo recording would have been compensated already for that cross talk?
 
Short answer: no. As it would depend on a lot of factors.
If he were listening nearfield, the cross talk would be of a lesser influence than me, at my listening distance to my array.

However it is true it will vary among recorded material.

Just try if you hear tonal differences between phantom voices and side panned voices. The phantom thread has such samples.
Then try it with songs. You'll be amazed at what more you can get out of a recording, in more than one way.

I've been playing with these concepts for years on end, it is very rewarding. Going back to a system without it is simply no option anymore.
Different setup will no doubt have different effects on the audibility. The room is a very large factor. So is the directivity pattern of the speakers.
This cannot be accounted for in all recordings without messing up playback on other devices.

Read some of the reviews of the Bacch system. How do they describe what they hear?
Yes, some producers use more tricks than others. But overall it has been a fun journey that won't end soon for me :D.
 
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A quick 8 song session shows there's something in this scheme that might work. Central vocalist seem to have the brightness known from side panned vocals without being in your face or annoying. Nuances in vocals come over quite well, still needs some adjustments though. And time, time to see if it holds up over that time.
As it is a little bit different than what I hear usually, it's easy to think: better! But it may just be: different!

Enjoyed Roger Waters with Perfect Sense Pt. 1. Love the female vocalist., P.P. Arnold on that song.

I still think I've been closer to a valid solution as not all intelligibility is there yet. That might be a hundred different things, but in the past I've heard better.
Where some vocal lines just pop out for the first time and be easy to follow. That wasn't here yet.
 
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