Coming in a bit late on this thread, but I quite understand what Mysticradio wants from his gear.
I am a solo-act, vocals (Audix mic), guitar through an effects unit and stereo backing tracks. I too want the stereo effect and need some punch too as my crowds are rarely less than 150 and often 300-500. When it's even bigger and outside then I have 3kW in boxes to cope with that.
My choice was to get 2 L1 systems with 2 B1's on each.
Sure it's easier to set up my traditional speaker cab's, as you argue there's only 4 pieces to do ( 2 cabs + stands) against 10 for the Bose systems. But the timed "saved" isn't really worth mentioning... about 5 minutes. I just turn up a little earlier
Whatever the other arguments, which I respect totally as we all have different tastes and ideas, my choice was for the sound quality. I have never had so many compliments since using the L1's and never (so far) complaints about volume levels.
Like others have mentioned, for small gigs (cafés and small halls with few people) one system in mono is perfect.

Still have my L1 2
but got the QSC K12s and soundcraft board.
wow....IM IN STEREO !!!!
IM renting out my L1 sys and people are happy and get lots of compliments

Has anyone thought of using a small mixer and hooking up left output to one compact and right output to second compact. This may solve the stereo issue but does put a small crimp in portability. With a small mixer you can build this for about 2100.00 and based on specs the whole system will be about 60 pounds and set up in less than 5 minutes. Any input on this idea?

quote:

Originally posted by EVI King:
Has anyone thought of using a small mixer and hooking up left output to one compact and right output to second compact. This may solve the stereo issue but does put a small crimp in portability. With a small mixer you can build this for about 2100.00 and based on specs the whole system will be about 60 pounds and set up in less than 5 minutes. Any input on this idea?

Should not be any problems. I've done exactly this with two older L1 Classics, and have also recently run this way with an L1 Classic and an L1 Compact.

Key point is to pan all mono (mic) inputs hard to one side or the other.

quote:

Key point is to pan all mono (mic) inputs hard to one side or the other.

Seems I missed a point... Why ?

Hi AlanC76

quote:

Originally posted by AlanC76:

quote:

Key point is to pan all mono (mic) inputs hard to one side or the other.

Seems I missed a point... Why ?

Please see Localization for an article about the principles involved.

Thanks ST.
I think I already understood that aspect but considering I often need alot of power, I use the 2 L1's + 2 subs each with stereo backing tracks going L/R to the L1's at high volume.
If I pan my mic to just one L1, am I not going to be underpowered compared to the tracks ?
I work solo and am centre stage with the L1's left and right of me. I have also found by placing the L1's front stage and me slightly behind I can hear myself quite adequately and overcome the feedback problem at high levels.

Hi AlanC76,

Let's start with this idea.

If you run the same signal into two L1®s:

• If they are placed side by side,
  - you will get about 3 dB gain in Sound Pressure Level. That is a noticeable difference, but just barely noticeable.
  
  edit: The B1s however may provide more than 3 dB gain if they are close together. (up to 6 dB).
  
  
• If you separate the two L1®s you get more coverage (roughly equivalent to the distance between them).
  
  edit: Separating the B1s results in a loss of the acoustic coupling and a loss of up to -3 dB.
  
  
• If you separate the two L1®s you may also run into multiple source interference that can sound like this:
  Hot and cold spots in the audience area
  Tonal coloration
  Poor speech intelligibility
  Lack of music clarity
  Poor gain-before-feedback
  Poor imaging
  
  You may not hear these issues on the stage, but out in the audience they may be more apparent.
  

We get to an odd point in the discussion that running a single source (for example your vocal) through two L1®s may cause audible problems, but it may not. That is going to depend on the room and the placement of the L1®s. But the risk is there, and the benefit (up to say 3 dB or slightly wider coverage) is relatively low.

Interestingly, you have similar issues with stereo. The portions of the tracks that are actually mono may also suffer from multiple source interference. This may be audible or not.

What I have found in practice is - I hear the best vocal clarity and when a vocal is heard through a single L1®.

If you are concerned about the volume, just turn up the volume for the vocal. Unless you are running both L1®s at their full output, you can probably keep the vocal on top of the tracks.

I understand that you work at centre stage and this may seem like an odd idea - to have your vocal coming from on side. How far apart are the L1®s?

This message has been edited. Last edited by: ST,

Typically, the L1's are 4 to 6 meters apart.
Sometimes more, rarely less.

Thanks for all your help ST !

quote:

Originally posted by AlanC76:
Typically, the L1's are 4 to 6 meters apart.
Sometimes more, rarely less...

At the larger distance (6 meters =~ 20') there shouldn't be too much of a concern about having the voice come from both L1's. At 4 meters or less, I'd stick with the vocal from just one L1.

I play keyboard and sing in a room with 2 L1's about 6 meters apart -- at least twice a week. I use a single keyboard controller and two sound modules (one internal to the keyboard and one MIDI-connected external). One sound module goes to one L1, the other to the 2nd L1 -- great sound when just using one or both. My mic (and all 6 other mics used by other people) are all routed to JUST ONE L1 (4 to one, 3 to the other). No one has ever said "it's kind of odd that your voice comes from one place while the accompaniment comes from several places" -- it is most natural, particularly when the mic is routed to the L1 closest to the person using it -- but even that is not too crucial.

While I can direct the vocal to both L1's (and have tried it that way), it doesn't "help" ... and is not at all necessary in order to have the vocal louder than the accompaniment.

Thanks for that Dan.
I'll certainly try different setups for the vocals and guitar in my next gigs.
Problems are, I don't often play the same gig more than once a year so have to adapt to each new situation.
Also, being solo, I can't be "out in front" to really appreciate what the sound is like.
Maybe next gig I'll try using my cheap and nasty headset mic' and go out front and compare different settings.

quote:

If you run the same signal into two L1®s:

If they are placed side by side,
- you will get about 3 dB gain in Sound Pressure Level. That is a noticeable difference, but just barely noticeable

Hi ST. A friend of mine here in France is a sound engineer and reckons there could be alot more than 3dB extra gain placing the 2 system side by side. I'll certainly check that.

Question is... how to do so ? In mono, I run all my inputs to the mixer panned one side and use L or R output to the Bose. But with 2 systems ? Is there a line out on the L1 model 1 that could feed the 2nd system ?
Thanks (yet again !)

Hi AlanC76

Thanks for posting that (above). I took a closer look at my post and I have added made some edits

quote:

Originally posted by ST:
If you run the same signal into two L1®s:

• If they are placed side by side,
  - you will get about 3 dB gain in Sound Pressure Level. That is a noticeable difference, but just barely noticeable.
  
  edit: The B1s however may provide more than 3 dB gain if they are close together. (up to 6 dB).
  
  
• If you separate the two L1®s you get more coverage (roughly equivalent to the distance between them).
  
  edit: Separating the B1s results in a loss of the acoustic coupling and a loss of up to -3 dB.
  ...
  

I am doing some more research on the gain you can expect by adding a second L1®. In the meantime...


There is a good discussion about Stereo vs. Mono in a Live Setting

The following is quoted from Hilmar-at-Bose in that discussion.

...
One method that is often mentioned is "dual mono". That means setting up two speakers on either side of the stage but feeding them exactly the same signal. This is mainly done for coverage reasons. Most horn-based speakers have a triangualar (as seen from the top) coverage area which doesn't map very well for a rectangular audience shape. So the basic idea is that the left speaker covers the left half of the audience and the right speaker the right half, but both speakers emit the exact same signal.
Since the Cylindrical Radiator(tm) loudspeaker has a very wide horizontal coverage area, it doesn't make much sense to run them in dual mono (why would you ?).


...
Personally I do favor the "single" L1 approach. When you use two systems for the same signal on stage, each system will provide excellent coverage for the full audience area (in contrast to most conventional systems), so most listeners get two pretty much identical "copies" of the orginal signal, except that they arrive with at two slightly different times (unless you are right smack in the center). That will result in some "comb-filtering", so spectrally the single L1 version is clearly superior. Spatially, its more a matter of preference. In general, two systems will provide for a wider, less distinct image, although it will mostly collapse on the nearest system. For anything but a solo performance I think you are better of with a distinctly localizable image (i.e. sinlge L1). For a solo act, it's a tradeoff but I haven't done enough work on to have a clear preference for myself.

...
Not everyone runs a "stereo" PA in dual mono, but most experience sound people do.

With most dual mono systems the "interference" between the two signals is somewhat less pronounced since the speakers provide uneven coverage. E.g if you are on the left side of the audience the level coming from the left speaker is usually significantly higher than that from the right speaker so the interference is limited.

The source of the delay is NOT in the amplification but simply due to the time it takes the sound to travel from each speaker to your audience position. Sound travels at about 1 millisecond per foot. Say the stage is 20 feet wide and you are 20 feet away from the stage and 5 feet off center towards the left. Using good old pythagoras we find that your distance to to right speaker is 25 feet and your distance to the left speakers is 20.6 feet. That means sound from the left speaker has to travel 4.4 feet less to get to you and reaches you 4.4 milliseconds earlier than sound from the right. You cannot compensate with a processing delay, since the number to dial in is different for every location in the audience. In this example, if both speakers would emit a tone at 114 Hz, the tones would be exactly out of phase at your position and would cancel out. For 228 Hz they would be exactly in phase and would add with +6dB of gain (instead of +3dB what you normally would get for two speakers that are far apart).

Whenever it make sense to use a second system for added coverage you should use the appropriate delay. If its less than 20 feet you certainly wouldn't need a second system but if its more you definitely would benefit from a delay.

---

I'll see what else I can find for you.

I have two L1's and have used them like a traditional PA, one L1 on each side of the stage, about 6 meters apart. I have found that they sound much better on stage at about 2 meters apart.

When you get out in the audience, the stereo effect is the same no matter how apart they are (especially in the back of the room). But on the stage, I want them close enough to place the B1's (two on each side) right next to each other in a cluster of four.

The vocal sounds really clear when run thru just one of the L1's.

Many thanks ST and c-hizer !

I think I'll go for the "c-hizer" solution
The idea of stacking the 4 B1's should create some serious sub !
ONce setup, I'll just have to test panning the vocals to one or other L1, same for guitar and see what the stereo backing tracks sound like in this situation.

Will keep you informed !

Hi Folks,

Lots and lots of good advice and information here.

Most of what I would say has been said.

A few things to highlight:

The most you can ever ever get from putting two sources fed by the same signal together is 6 dB. The reason? sound waves add in space through the principle of superposition. If the waves from two sources perfectly add, you get twice the amplitude, which is 6 dB. Now, I've been proven wrong on a number of occasions, but if that happens on this occasion, Alan, the sound engineer you've been talking to is going to get a Nobel Prize.

The problem is that to get the full 6 dB the two sources have to be spaced very closely together relative to a wavelength of sound. at 50 Hz, where the wavelength of sound is about 20' (about 7 meters) that's pretty easy to do. Massing your B1 bass modules is done for this reason -- to get the 6 dB per doubling of B1 systems. But at 1,000 Hz, where the wavelengths are 1' (about 30 cm) you just can't do get L1 speakers close enough. As a result, you get something less than 6 dB because at some angles instead of the sound waves constructively adding they will destructively cancel (one will be partly or completely out of phase with the other.

Once you separate the sources by several or more wavelengths, the summations and cancellations are so numerous and so complex that we say the two sources are essentially uncorrelated (not strictly true, but for the purposes of this argument, a very close approximation.) When two sources are uncorrelated the only thing you can count on is that the total amount of acoustic power going into the room will be doubled. Doubling the power is 3 dB.

So what we've said is 1) put B1s together if you can because they'll give you an honest 6 dB per doubling of B1 systems; 2) if you are sending a mono or stereo signal to spaced L1 systems, try to space them 20' (7m) or more if you can because this will minimize any audible cancellations.

Alan, you've got enough spacing of your L1 systems and so I really don't see any problem with destructive interference. On the other hand, given the maximum benefit in level is only 3 dB, and you are somewhat reducing the clarity and accuracy of localization, I question the benefit. Your willingness to experiment is a good ingredient.

I'm going to work next week on a Wiki article on this subject, someplace where I can try to put these thoughts together where they can be found time and time a again.

Ken

Interesting discussion

a question though.

Say you were running a number of sources (say Bass, Drums, 2 guitars and 2 vocals) through one L1 with 2 B1's with optimal gain staging and the master volume at 12 o'clock.
you get a certain volume

if you then add a second L1/2B1 system and evenly separate the sources across then so sys 1 has Bass, 1 gtr 1 Vox and the rest goes through the other. If the gain staging were Identical and both masters were at 12 how much more volume would there be over the single system?


thanks

quote:

Alan, you've got enough spacing of your L1 systems and so I really don't see any problem with destructive interference. On the other hand, given the maximum benefit in level is only 3 dB, and you are somewhat reducing the clarity and accuracy of localization, I question the benefit. Your willingness to experiment is a good ingredient.

Great reply Ken, thanks !
Couple of thoughts : the 4 b1's (2x2) stacked interests me the country gigs I do the dancers love the solid bass that gets your chest thumping ! So to do this, the L1's would have to be pretty close together. My idea would be to run them stereo as close as possible with the 4 B1's in the middle, run the backing tracks in stereo, vocals one side, guitar the other. What do you reckon as opposed to running everything in mono to both systems ?
Also, I asked previously if there is a line out that could feed the 2nd L1 from the 1st ? Still not too sure how to connect for best results.
BTW, I use a common or garden Behringer Xenyx mixer.
Thanks again !

ALan

Hi Sparky G,

quote:

Originally posted by SparkyG:
Interesting discussion

a question though.

Say you were running a number of sources (say Bass, Drums, 2 guitars and 2 vocals) through one L1 with 2 B1's with optimal gain staging and the master volume at 12 o'clock.
you get a certain volume

if you then add a second L1/2B1 system and evenly separate the sources across then so sys 1 has Bass, 1 gtr 1 Vox and the rest goes through the other. If the gain staging were Identical and both masters were at 12 how much more volume would there be over the single system?


thanks

There was a great discussion about things like this back in 2004.

Here is a post from back then that seems on topic.

quote:

Originally posted by Hilmar-at-Bose:
Oldghm

quote:

So if we have 5 bandmates on stage with PASs (5 X 750 = 3750 watts) each at 95db at 12 ft. What happens to the db spl of the group as a whole?

at a spot where you 12 feet away from all 5 players and they are all playing different things you would get about 102 dB.
The rule-of-thumb here is that you get 3 dB for every doubling, i.e. 3 dB for 2 players, 6 dB for four players and about 7 dB for 5 players.
Please note, that in a typical band setting the players rarely play at the same level at any one point in time and that usually the overall level is determined by the loudest player (singer or soloist).

ST

quote:

Thanks Hilmar. I was afraid it was one of those ... the answer depends on a myriad of inter-related and seemingly unrelated factors ... types of things.

I think my ears understand all of this better than my head does.

You're not alone. I have a Ph. D. in acoustics and EE, tought at college, worked in commercial and academic research for 15+ years and it sometimes still confuses the heck out of me. It's a good thing we have those ears

Hilmar

Original Post

Did it !


All mono setup.
Truly amazing sound, far less feedback issues with the mic' and the subs just made the building rumble !!