# Line Array Boxes -- SLS?



## Jezza (May 18, 2008)

Hey all -- working on the redesign to my schools theater and am arguing with the AV consultant about the correct kind of line array to install.

He's got spec'd a 20 cabinet per-side SLS LS6500 system with Lab Grupen Amps. Not only do I not really trust a ribbon-based cabinet but it also seems unnecessarily large.

Other have suggested, and I agree, and than a Nexo line array (like the GEO S1210) would sound much better, and the same coverage could be achieved with only 10 boxes per side. The use of Nexamps with internal processing would be advantageous. I'd also like to run the system on Ethersound and the Nexamps support it natively.

I haven't been able to do a shoot out between the two boxes -- anyone had any experience with either of these and can give an opinion either way?

Thanks!


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## museav (May 18, 2008)

Jezza said:


> Hey all -- working on the redesign to my schools theater and am arguing with the AV consultant about the correct kind of line array to install.
> 
> He's got spec'd a 20 cabinet per-side SLS LS6500 system with Lab Grupen Amps. Not only do I not really trust a ribbon-based cabinet but it also seems unnecessarily large.
> 
> ...


Can we step back? The proper speaker system solution is going to be application dependent, so can you tell us more about the application such as some about the room, the type of events, the budget, etc.? And how were the options being considered developed, were they selected specifically for how they serve your specific application or was it more based on selecting a manufacturer or model and then trying to make it fit the application? Has anyone done and predictive analysis for the results expected from what is being considered? Has anyone even verified that a line array solution is the best option for the space or is it simply an assumption? While 10 boxed versus 20 boxed does seem to indicate there may be some significant differences, it is difficult to compare two systems without enough information on the specific application. In fact, without enough information it is difficult to even know if either appears to be a good solution.

Can you also expand on your comments. Why don't you trust a ribbon based speaker? Why do you feel the Nexo would sound much better? Why do you want to use EtherSound? Have you discussed these thoughts with the Consultant? You may have very good reasons for these comments but knowing the reasoning behind them might help others better understand your goals and concerns. I always find it very helpful to know not just that someone wants a specific product but to also know the why that is behind it as that may then provide additional insights or extend into other areas of the system.


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## Eboy87 (May 18, 2008)

To echo what Muse said, is a line array really appropriate for the space? There's more to choosing a speaker system than just what looks cool and what everyone's using. In my opinion, sound quality and coverage should be the first two things taken into account. It's simply the right tool for the right job attitude.


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## len (May 18, 2008)

I've heard Nexo, which is good. Never heard SLS. And as others have said, it's really hard to say one is better than the other without knowing the venue.


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## avare (May 18, 2008)

Previous posts have identified knowing more about the application is required to give an informed response.

Working from what has been written, doing minimal research on the web showed that the SLS box uses a 6.5" driver, has a usable low frequency of 80 Hz, has a fixed horizontal coverage of 110° and is 184 mm wide. The Geo box uses a 12" driver, has a usable low frequency of 80 Hz, has a selectable horizontal coverage of 80 or 120°, and is 360 mm wide.

Ignoring other technical aspects, 20 of the SLS box make a line array roughly the same length as 10 of the GEO. In other words 20 of one equals 10 of the other in line array length, which determines the system's low frequency directivity.

As far as the other technical aspects, it depends on what the spec for the system is (see previous posts).

Andre


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## Jezza (May 19, 2008)

Sorry all -- I should have known from all my other posts on the Booth that more info was needed -- I was just exhausted when I was posting the other day.

High school renovation -- brand new lighting and sound systems being installed in a geodesic dome auditorium. Capacity currently is 1k however, with the addition of a balcony, we should be up to 1.2k when all is said and done.

A line array has been spec'd due to the programming, the space, and the decibel level required. Choral, orchestral, jazz, rock, theater, drama, dance, you name it, its happens on this stage. Being a dome, its a weird space and has some flutter echos. New clouds being installed w/ absorption and reflection as well as absorption curtains on the walls. The balcony is 80'+ from the proposed array -- sort of a long narrow room so the AV consultant has proposed a significant amount of boxes near the top of the array at a 0º to get the sound out there.

Under balcony fills will exist as well as front fills. 

Budget, around $100,000 for the array, maybe more depending. 

Not married to any specific manufacture, however, based on recommendations by many local acousticians and live sound engineers, the SLS boxes will not deliver as the AV consultant promised. Nexo, sort of being the next in line in terms of pricing and quality has been suggested as an alternate.

Coverage plots have been developed for both systems and seem to indicate that 10 box per side Nexo will have the same approx. coverage as a 20 box per side SLS.

Ribbon line array? Don't think they would end up being as durable in the long run -- especially with the high decibels needed for MANY rock/talent shows every year. We are intending for this to be a rented space as well and I don't want to have to worry about a delicate speaker that won't take well to the abuse an untrained sound engineer can dish out. 

The Nexo speaker looks much more durable and has many more hanging and rigging options. I'm still pushing to make sure this system is on motors and not dead-hung so it can be brought in easily for service or re-aiming as I'm sure they aren't going to get it right the first time -- the room is too weird. Also, esthetically, a 20 cab system is huge in that room, almost hits the top of the floor mounted subs (Dual Nexo 18" per side -- it would seem a full Nexo system would make sense...) The 10 cab system even with slightly larger boxes is much more pleasing and will not look so hulking. 

Ethersound (or another digital protocol) is a must. Console (Yamaha M7CL-32) needs to be able to plug in not only from the booth but also at mix position in the house. I'm feeding a full 32 channel analog snake from the stage to the console at both positions, however, I have a rack of 16 wireless located in the booth w/ digital preamps that wants to be routed to the console at mix position without actually moving the rack (its got a lot of other gear in it, and moving anything of that size out of the booth and down some stairs really isn't an option). Hence, expansion slots being used for some digital protocol to get control over the digital pre-amps (not worried about remote gain control). 

Ethersound may play in in another way too. We've got a "daily use" rack backstage which needs to feed through into the processing and amps backstage. If a DME was installed back stage with the appropriate cards, it could take signal from the "daily use" rack and feed it the processors, but it could also take signal from the wireless rack in the booth and feed it via Ethersound to the console. A simple ethercon patch would need to be made to transfer the control from booth to mix position. Assuming we are sending signal up the Ethersound, and since its bi-directional, all sends to processing could be made via Ethersound as well -- leaving all 16 analog omni outs on the console for direct returns to the stage. 

Thanks for all your thoughts -- looking forward to reading your responses.


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## soundlight (May 19, 2008)

I've heard of numerous problems with Ethersound from an installation standpoint. Go Cobranet if you can. It's a much better protocol. And from my experience, Cobranet is easier to work with, and compatible with a wide array of gear.


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## avare (May 19, 2008)

Bottom line, ignoring your subjective opinions and ignoring facts is that the recommended LF crossover frequency for the SLS speakers is 160 Hz. Without knowing the specific model of the dual 18" subs, I have have never seen or heard of an 18" cabinet for live use that can be crossed over that high.

IOW words, the SLS SL6500 are mismatched to the subwoofers.

Andre


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## avkid (May 19, 2008)

avare said:


> Without knowing the specific model of the dual 18" subs, I have have never seen or heard of an 18" cabinet for live use that can be crossed over that high.


Does our "little" 6x18 count?


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## howlingwolf487 (May 20, 2008)

avkid said:


> Does our "little" 6x18 count?



:shock: What's your slogan for it? "More punch than Rocky Balboa and more throw than an outfielder"?


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## avare (May 20, 2008)

avkid said:


> Does our "little" 6x18 count?



I had a look at your website and well very impressive.

Looking at the specs on the 618C, I am not certain how it would work with a 160 Hz crossover point. The specs are an "operating frequency range" of 30 Hz to 200 Hz, and a "frequency response" of 41 Hz to 140 Hz, while the "cutoff" is 100 Hz 2nd order. What is the definition of each? 

Crossover frequency selection traditionally with 6 dB/octave to 18 dB/octave slopes is based on, among other factors, the drivers being capable of smooth response an octave beyond the crossover frequency. If this applied to the 618C, then "cutoff" of 100 Hz 2nd order, fits this principle. If one assumes with steeper filter slopes that the range of smooth beyond the crossover can be reduced by half an octave, then a crossover point of 
140 Hz could be used, which fits with the "frequency response" upper limit of 140 Hz. That is still below 160 Hz though.

Regardless, it is a very impressive subwoofer. Thanks for the info!

Andre


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## museav (May 21, 2008)

I'll start by saying I'm sorry for the long response, just a lot to address.


Jezza said:


> Being a dome, its a weird space and has some flutter echos. New clouds being installed w/ absorption and reflection as well as absorption curtains on the walls. The balcony is 80'+ from the proposed array -- sort of a long narrow room so the AV consultant has proposed a significant amount of boxes near the top of the array at a 0º to get the sound out there.


That would certainly be a weird space as flutter echo occurs between parallel surfaces and is not usually associated with domes that instead tend to experience issues such as creep and focusing. Anyways, I'm having trouble reconciling a dome and an 80' distance to the balcony with it being a long narrow room. I just can't quite picture that, a dome with a stage in it would seem to result in a room that is wider than it is long and a 1,000-1,200 seat room that is 80' deep would normally be fairly wide. So I'm just having difficulty envisioning the space.

You mentioned having a Consultant. I'm not being a smart ass but if you trust their selection of a line array then why don't you trust the line array they selected? Or, if you don't trust the specific products they recommended then why the apparent trust in the general recommendation of a line array? Just to be clear, I am not pushing the SLS line array solution and there may be valid concerns with it, but it seems that you may be looking for reasons dismiss it and justify a Nexo line array solution instead. If that is true or if there is any reason you want a particular manufacturer or model or technology then please just make that clear to the Consultant and avoid their wasting time on developing other solutions.


> Not married to any specific manufacture, however, based on recommendations by many local acousticians and live sound engineers, the SLS boxes will not deliver as the AV consultant promised.


The SLS arrays may not have the maximum output of many other line arrays but that does not mean they are not capable. I am curious as to what these other people are basing their comments on, it is a little difficult for anyone to assess whether any system might work or to suggest any alternates without knowing any specific requirements you are using to define the acceptable system performance.


> Nexo, sort of being the next in line in terms of pricing and quality has been suggested as an alternate


I'm not quite sure what determines "next in line". It was not clear if the $100,000 budget was for just speakers or speakers, amps, processing, etc., but in any case there are likely a number of options within your budget. Potential factors could include rider acceptance, aesthetics, weight, output level, coverage and so forth. There is certainly nothing wrong with Nexo, but there may be other good choices all depending on what your criteria are.


> Ribbon line array? Don't think they would end up being as durable in the long run -- especially with the high decibels needed for MANY rock/talent shows every year. We are intending for this to be a rented space as well and I don't want to have to worry about a delicate speaker that won't take well to the abuse an untrained sound engineer can dish out.


The SLS system will not necessarily provide the same output levels as many other line array systems, but they are professional products and are not "delicate". The system processing should provide the protection necessary and you should not be letting untrained operators or anyone not very familiar with the system adjust that processing.


> Ethersound (or another digital protocol) is a must. Console (Yamaha M7CL-32) needs to be able to plug in not only from the booth but also at mix position in the house. I'm feeding a full 32 channel analog snake from the stage to the console at both positions, however, I have a rack of 16 wireless located in the booth w/ digital preamps that wants to be routed to the console at mix position without actually moving the rack (its got a lot of other gear in it, and moving anything of that size out of the booth and down some stairs really isn't an option). Hence, expansion slots being used for some digital protocol to get control over the digital pre-amps (not worried about remote gain control).


Maybe I'm misunderstanding what you are planning on doing and maybe you already know this, but EtherSound is not digital audio like AES3 or ADAT, it is a long run audio and control transport like CobraNet or Aviom's A-Net or DANTE. Thus, unless your preamps directly support EtherSound, you would have to have an interface at the wireless rack.


> Ethersound may play in in another way too. We've got a "daily use" rack backstage which needs to feed through into the processing and amps backstage. If a DME was installed back stage with the appropriate cards, it could take signal from the "daily use" rack and feed it the processors, but it could also take signal from the wireless rack in the booth and feed it via Ethersound to the console. A simple ethercon patch would need to be made to transfer the control from booth to mix position. Assuming we are sending signal up the Ethersound, and since its bi-directional, all sends to processing could be made via Ethersound as well -- leaving all 16 analog omni outs on the console for direct returns to the stage.


I'm not sure I completely follow everything but it sounds like a simple EtherSound interface at the "daily rack" might be more cost effective than a DME and cards. However, you have to look carefully at the actual ES configuration and wiring as although EtherSound will support 64 bi-directional channels of 24 bit/48kHz audio, you still have to address how those channels are routed and how the signals flow, it can sometimes get a little complicated. I just recently had an application where the users wanted EtherSound but we quickly found it did not work well for their application due to the network infrastructure available and the signal routing required. And you probably already realize this but it may be worth a reminder that while you can use an EtherSound card in the M7CL and free up physical ports, you are still working with the same 27 buses (16 mix, 8 matrix and L/C/R or L/R/Mono).


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## avare (May 21, 2008)

*Crossover Frequency - Part II*

Sometimes the basics are forgotten, as I did when first writing about the crossover frequency. Frequencies at 160 Hz are detectable for location by the human ear. If the plan is to use the subs on the ground(floor?, stage? we need more information!) then the low frequency range that the ear can locate will cause a strange image of the higher frequencies coming from the array and the lowest half octave or so coming from the subwoofers.

Coming back to what was written earlier in this post, more information is needed. I too am confused by a dome shape with long narrow auditorium.

Andre


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## Jezza (May 23, 2008)

First off -- I'm a lighting guy, not a sound guy -- lets just get this out on the table.

I am friends with and have shown all the specs to several very reputable rock n' roll and theater live sound engineers and consultants who have weighed in on the system. Many of my opinions and ideas are based off their suggestions -- which I trust to the fullest.

Round dome w/ the sides cut off due to interior walls. The green room and storage parallel surround the audience. 56' wide stage x 30'. House is approx. a trapezoid 56' at one end and about 70' at the other w/ about a 100' throw to the back wall. 

We didn't hire the consultant -- the architect did. I have a general distrust for both of them due to other parts of this project they tried to sneak by the school district which I caught before it went out to bid the first time -- saving $600k. I will not go into detail.

Everyone on the project has agreed a line array is the best type of speaker orientation for the room -- we are just differing on opinions about manufacture right now. I've made my opinions about the SLS boxes clear, as has he about the Nexo. I was simply asking if anyone had any opinions about the boxes or the sound quality -- I wasn't asking for a schooling on how I should talk to or deal with our consultant, thank you. 

Next in line referring to price point, size, comparability. What other boxes would you recommend I look into.

I'm not letting people adjust the processing, but an untrained board op still does have the potential to overdrive or blow speakers if they aren't competent -- this is a high school -- things will happen. 

We are still talking about Ethersound or Cobranet -- on or the other will be needed in some form. I've heard that there are some inherent patching problems with Ethersound and that Cobranet is more stable. However, the Nexamps don't support Cobranet natively I don't think -- that's why we were thinking Ethersound initially. 

The pre-amps we are thinking of are Ethersound compatible. 

Thanks


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## TimmyP1955 (May 25, 2008)

I have a pair of SLS LS8695s, each of which is a column that is the equivalent of eight LS6500s with no vertical splay. In a room that is about 55x75, they have enough output for anything but rock (and other "rock level" shows). I have beat these things pretty hard, and still have all of the original ribbons working fine. The problem with these "no splay" boxes is that there is no vertical dispersion - the listeners ears all have to be within 30" of each other height wise. In my current venue there is an ears height variance of about 90", so I use fills. What I need is a line that's twice as long, with a little splay capability.

If you have a balcony, you need the line to be hung high so the balcony is a straight shot from the top part of the array. The array can then be shaped to give the most even coverage of the floor. The longer the line, the less low frequency spill to the floor and ceiling.

I expect that the Nexo will play louder. It may also sound better. I should think that it will also be very much more expensive.

Also have a look at:

Welcome to A-Line Acoustics (They have a column that has splay on the bottom.)

Danley Sound Labs (Non-line solutions.)

VTC Pro Audio (Danley technology in line form.)


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