mono rear fill speakers?

[DVDdoug]

Do I need to add a delay to the rears?...

...Should the rear speakers be calibrated to be lower in volume by 3-6dB?

Whatever you like!!! It's a "creative effect" for you enjoyment so there's no right or wrong way.

...I'm not keeping-up with exactly what you're now doing but if you are doing the Halfler/matrix subtraction the results depend on the "difference information" in the stereo recording so every song will be different anyway... If left and right are identical (dual-mono) of course subtraction gives you nothing from the rear.

There is a potential advantage to delay - Phase of the acoustic waves depends on the wavelength, the speed of sound, and the distance, and any added delay. (High frequencies* have shorter wavelengths so more phase shift/difference than low frequencies.) So the relative front-rear phase gets "randomized".




* if you listen to a constant 5kHz tone the wavelength is 2.7 inches. If you move your head slightly you'll hear drastic loudness changes as the waves from the left & right speakers, and direct & reflected waves go in-and-out of phase. Of course, your left & right ears aren't in the same spot so that's added "weirdness". Luckily, we don't normally notice this with constantly-changing music! With bass you get similar effects but you have to move around the room more and it's more noticeable with music.

 

[olds1959special]

Whatever you like!!! It's a "creative effect" for you enjoyment so there's no right or wrong way.

...I'm not keeping-up with exactly what you're now doing but if you are doing the Halfler/matrix subtraction the results depend on the "difference information" in the stereo recording so every song will be different anyway... If left and right are identical (dual-mono) of course subtraction gives you nothing from the rear.

There is a potential advantage to delay - Phase of the acoustic waves depends on the wavelength, the speed of sound, and the distance, and any added delay. (High frequencies* have shorter wavelengths so more phase shift/difference than low frequencies.) So the relative front-rear phase gets "randomized".




* if you listen to a constant 5kHz tone the wavelength is 2.7 inches. If you move your head slightly you'll hear drastic loudness changes as the waves from the left & right speakers, and direct & reflected waves go in-and-out of phase. Of course, your left & right ears aren't in the same spot so that's added "weirdness". Luckily, we don't normally notice this with constantly-changing music! With bass you get similar effects but you have to move around the room more and it's more noticeable with music.

Yes, it's definitely the Hafler/matrix subtraction because mono records play nothing from the rears and on some records it almost completely takes away the vocals. I see how they are making Karaoke tracks this way.

 

[DVDdoug]

What amount of delay would be appropriate to experiment with?

You usually need at least 20-50ms before you perceive a delay. With a shorter delay you'll mainly perceive the sound coming from the direction of the earliest sound and possibly some "phasing"/comb filtering effects. A 1-second echo is probably too much (and I have no idea if the miniDAP has enough memory for that). Sometimes a delay of about 1-beat (maybe 200ms) is "fun" but of course that depends on the tempo. Again, whatever you like!

Given the distance, I might BOOST the rear volume to better hear it...

 

[olds1959special]

You usually need at least 20-50ms before you perceive a delay. With a shorter delay you'll mainly perceive the sound coming from the direction of the earliest sound and possibly some "phasing"/comb filtering effects. A 1-second echo is probably too much (and I have no idea if the miniDAP has enough memory for that). Sometimes a delay of about 1-beat (maybe 200ms) is "fun" but of course that depends on the tempo. Again, whatever you like!

Given the distance, I might BOOST the rear volume to better hear it...

I liked 13 ms, maybe because the 6-7 feet adds around a 7ms delay.

I turned down the rears about 5dB (from listener position).

 

[Wayne Highwood]

Cool, glad it's working. Yes, ideally the rears are attenuated and delayed such that they don't draw direct attention to themselves, but provide that enveloping "enhanced stereo" effect. Play with levels and delay as needed.

You'll find a lot of variance in recordings, where good live recordings that are a bit wet (capture the phasey reflections and natural reverb from the performance) can really come to life, but others that go full Strawberry Fields Forever with the pans and phase can sound a bit ridiculous.

Have fun re-experiencing your music collection!

 

[bmc0]

Here's Doug Rife's take on this idea.

 

[olds1959special]

Here's Doug Rife's take on this idea.

Still enjoying this a lot!

 

[olds1959special]

still doing this but with the addition of the horizontal mono center speaker on my desk.