Lab Subs

[John Chiara]

Did a flood relief outdoor event yesterday. The last band had no bass amp...bass was DI into snake.
I was using 6 admittedly underpowered Labs across the front of the stage.
Very interesting how accurate the bass sound was. I had noticed it all day but with no amp it was clearly apparent the quality of the reproduction.

 

[Helge A. Bentsen]

Re: Lab Subs

I really like my Lab subs. It's a shame I rarely do gigs with my own PA anymore, it sounds excellent IMHO

 

[Tim Tyler]

Re: Lab Subs

John - I've taken to delaying the kick, snare & bass amp to the mains, makes a difference. Not as good as no bass amp on stage, however... -Tim T

 

[Jay Barracato]

John - I've taken to delaying the kick, snare & bass amp to the mains, makes a difference. Not as good as no bass amp on stage, however... -Tim T

I think you mean delaying the mains to the back line, assuming the mains are closer to the audience.

 

[Ryan Jodrell]

Re: Lab Subs

I think you mean delaying the mains to the back line, assuming the mains are closer to the audience.

I was gonna say, why are you putting the backline further behind?!

 

[Tim Tyler]

Re: Lab Subs

Ryan (and Jay...) - I delay the signal from these inputs whatever amount is needed so that when the acoustic signal from the original physical source reaches the front of the mains boxes, they are more or less in sync with the electronic signal through the equipment. I use an iLive which allows me to delay any input discretely, that's what I often do. Cheers - Tim T

 

[Art Welter]

Re: Lab Subs

Ryan (and Jay...) - I delay the signal from these inputs whatever amount is needed so that when the acoustic signal from the original physical source reaches the front of the mains boxes, they are more or less in sync with the electronic signal through the equipment. I use an iLive which allows me to delay any input discretely, that's what I often do. Cheers - Tim T

Tim,

As Jay and Ryan mentioned, adding delay to the inputs makes the back line even further out of time sync from the mains.

If the back line amps and drums are 15 feet behind the mains, to "sync up" the mains need to be delayed about 15 milliseconds, the time of flight from the back line.
If you delayed the back line inputs by 15 ms, they would be around 30 ms behind the PA.

15 ms is only perceived as a discreet echo at high frequencies, 30 ms is long enough to be perceived as an echo on any instrument or voice.

Delaying the instruments does make the PA seem louder than the backline due to the Haas (precedence) effect, that which we hear first seems louder.

Art

 

[TJ Cornish]

Re: Lab Subs

Tim,

As Jay and Ryan mentioned, adding delay to the inputs makes the back line even further out of time sync from the mains.

If the back line amps and drums are 15 feet behind the mains, to "sync up" the mains need to be delayed about 15 milliseconds, the time of flight from the back line.
If you delayed the back line inputs by 15 ms, they would be around 30 ms behind the PA.

15 ms is only perceived as a discreet echo at high frequencies, 30 ms is long enough to be perceived as an echo on any instrument or voice.

Delaying the instruments does make the PA seem louder than the backline due to the Haas (precedence) effect, that which we hear first seems louder.

Art

If you delay the backline inputs 15ms, the stage volume - which takes 15 ms to reach the speaker position - will hit when the electronic signal will - accomplishing the correct effect.

 

[David Sturzenbecher]

Re: Lab Subs

At one and only one point. And providing your mains are roughly 10dB level matched to your "acoustic" sources.

If you delay the backline inputs 15ms, the stage volume - which takes 15 ms to reach the speaker position - will hit when the electronic signal will - accomplishing the correct effect.

 

[Jay Barracato]

Ryan (and Jay...) - I delay the signal from these inputs whatever amount is needed so that when the acoustic signal from the original physical source reaches the front of the mains boxes, they are more or less in sync with the electronic signal through the equipment. I use an iLive which allows me to delay any input discretely, that's what I often do. Cheers - Tim T

You have more total electronic delay on your FOH than the number of feet behind them the back line is?

 

[TJ Cornish]

Re: Lab Subs

You have more total electronic delay on your FOH than the number of feet behind them the back line is?

Maybe I'm missing something, but what Tim does seems reasonable to me. His method allows delaying the backline inputs more than the front line if desired, rather than just delaying the whole mix back to some point on stage. Yes this is positionally dependent, YMMV, etc.

 

[Jay Barracato]

Maybe I'm missing something, but what Tim does seems reasonable to me. His method allows delaying the backline inputs more than the front line if desired, rather than just delaying the whole mix back to some point on stage. Yes this is positionally dependent, YMMV, etc.

You can delay the back line to the bleed into the front line, but that has nothing to do with the acoustic sound coming off the stage. In fact, you would be moving it further away from what is coming from FOH.

 

[TJ Cornish]

Re: Lab Subs

You can delay the back line to the bleed into the front line, but that has nothing to do with the acoustic sound coming off the stage. In fact, you would be moving it further away from what is coming from FOH.

Pretty sure you're still thinking of this backwards. Whether you put a delay on the LR bus or on the kick channel, the result is the signal (at least for that channel in question) is delayed - i.e. same result. This can be delayed all the way to the point or origin on stage (drum kit), or to the vocal frontline, but delay on backline channels should move the signals closer to being in sync, not farther out of time..

 

[Per Søvik]

Re: Lab Subs

What all of you write makes some sense since you are in fact referring to different things, some of them impossible.

Delaying an input, as TJ and others are pointing out, delays it in the mains so any delay applied, is in effect delaying the mains to let the acoustic sound catch up. Delaying the back line means delaying the back line in the mains, not delaying the actual acoustic sound coming from the back line. If the line between the mains is the reference line, than it is only a matter of delaying everything going into the mixer by the distance the microphone is behind that line (if it is a di-box, then the distance from the (loudest)sound source of the instrument).

 

[Jay Barracato]

Reconsidered... not worth pursuing since we are obviously talking about different situations.

I was responding to the way Tim phrased it which was backwards. He is applying delay in the mains to the back line, not delaying the back line to the mains as originally stated

 

[Jay Barracato]

You can delay the back line to the bleed into the front line, but that has nothing to do with the acoustic sound coming off the stage. In fact, you would be moving it further away from what is coming from FOH.

I found the snag. I left out the modifier ON STAGE. The complaint I was trying to state is the further you have to delay to match out front, the more out of whack the sources are on stage.

 

[Tim Tyler]

Re: Lab Subs

Per gets it, TJ gets it. Same procedure as setting delay stacks, with the backline as the reference point, or more accurately, elements of the backline. We are not making the backline farther away, we are making the mains "farther away" to line up with the backline input signals. This works best for percussive input and input with fairly long wavelengths, such as bass. -Tim T

 

[Randy Pence]

Re: Lab Subs

not sure if i understand this delaying procedure correctly:

1st delay PA tops to PA subs (optimizes sub/top xover overlap)
2nd delay individual acoustic sources to combined PA?
3rd? delay monitors to combined PA?

 

[Jason Lavoie]

Re: Lab Subs

delaying the mains or delaying every input results in exactly the same thing. he's just saying that he's only delaying the items (in the mains) that produce enough bleed to interact with the mains.

This of course assumes that your delay is post Aux if you're doing mons from FOH

Jason

 

[Art Welter]

Re: Lab Subs

If you delay the backline inputs 15ms, the stage volume - which takes 15 ms to reach the speaker position - will hit when the electronic signal will - accomplishing the correct effect.

You are correct, I was thinking in "olden day" terms where the PA was aligned to the backline with a DDL on the mains outputs, not individual channels.

That said, the LabSub horn path requires front loaded mains to be delayed around 11 ms to be in sync, added to around 2 ms overall latency in most DSP =13 ms system delay from the get go.
Assuming 15ms time of flight from the back line to the front of the time aligned Labhorn/ front load PA, anything over 2 ms delay added to the backline results in it arriving behind the mains.
Actually, there is already around another 2 ms latency in the digital console, so adding almost any delay to a properly aligned Labsub PA would put it behind (assuming 15 ms time of flight from back line to mains PA front line).

Now on to Randy Pence's third question:

" delay monitors to combined PA? "

The LF omni back wash of delayed monitors would be less apparent (Haas effect) out front, but the performers may not appreciate the extra delay time.
At any rate, what we hear of the monitors (or back line) in the house is a combination of reflections (echoes) of various lengths from around the stage walls and ceilings, alignment of all those sources to the mains is impossible.