PA DSP Options Mixer Vs DBX PA2

[Trdat]

I am keen to understand more about a decent option of DSP for a large venue. The sound engineer for the venue states that the QSC TouchMix 30 Pro has DSP and the specifications on the website does mention "room wizard to simplify equalization tasks." Does this DSP have enough taps and how would it compare to a DSP such as the DBX or other similar type DSP's such as the Silica?

Apparenlty the QSC even has the option to put a mic and play pink noise to get a measurement. If I am not mistaken the PA2 also has this option? Any input would be helpful.

And I am also looking into Audyssey's Pro Kit and how that might work with a live venue?

 

[Trdat]

And I am also looking into Audyssey's Pro Kit and how that might work with a live venue?

Just realised this is used with AVR's my apologise.

 

[ChrisG]

I am keen to understand more about a decent option of DSP for a large venue. The sound engineer for the venue states that the QSC TouchMix 30 Pro has DSP and the specifications on the website does mention "room wizard to simplify equalization tasks." Does this DSP have enough taps and how would it compare to a DSP such as the DBX or other similar type DSP's such as the Silica?

Apparenlty the QSC even has the option to put a mic and play pink noise to get a measurement. If I am not mistaken the PA2 also has this option? Any input would be helpful.

And I am also looking into Audyssey's Pro Kit and how that might work with a live venue?

Context: I'm a live sound engineer who has designed some interesting speakers for both domestic HiFi and PA use. I own a QSC TM30Pro, and use it for shows a few times a week. I also own a rack of Powersoft T-series amplifiers.

Some notes from me:
- The QSC TM30Pro is NOT a loudspeaker management system. It might be persuaded to act as one in some circumstances, though. The crossover slopes are fixed, the EQ is limited to a 6-band parametric EQ and a 30-band graphic on each output. It's certainly not ideal, but it could be done.
- Let's say, for a moment, that you've decided to go ahead and use the QSC desk as an LMS. You've used various outputs to drive various amps and speakers with different crossover points etc etc etc. Then, a sound engineer needs to mix a show. Will they have access to all of those settings? It would be quite easy to destroy most of the PA system just by loading a blank scene and playing some music.
- Following all of this, there's a reason why I put all of my crossovers/limiters/EQ in the DSP in my amps: it makes sense. I can lock everything down. Someone else could turn up, connect their preferred desk etc, and everything would be fine.


Now, if you simply wanted to use the TM30Pro to route to a few different coverage areas, that would be easy enough. It's still not ideal, but that's a better use for a device like this. Using it to configure a PA system, though, is not the intended use and there are a lot of ways it could go wrong.

Finally, the Room Tuning Wizard is similar to many other dumb auto-EQs. Download Room EQ Wizard, use a measurement mic, and do it properly.

Chris

 

[EERecordist]

I like and use the DBX, but testing on ASR shows its limits. It is an all-in-one crossover, EQ, auto room EQ, compressor limiter. It also has DBX's patented subharmonic synthesizer. Of course that is a nonlinear element, but it can please the crowd on some material. Like several systems, you can walk around the room with a tablet and adjust the main unit. It is not expensive, and easily available used. It is a great set and forget item, you can use your console upstream for creative effects like Fab Filter.

Many speaker makers have their own DSP systems specialized for concert halls, stadiums, or churches. Some have system design and simulation software like the L-Acoustics Soundvision software. Some have more crossover filter options. Some are designed for networked audio. I would test the user interface and price of each to see if you like it.

 

[Trdat]

Context: I'm a live sound engineer who has designed some interesting speakers for both domestic HiFi and PA use. I own a QSC TM30Pro, and use it for shows a few times a week. I also own a rack of Powersoft T-series amplifiers.

Disclaimer, I am not a sound engineer I am working on the acoustics in a wedding hall and have brought the RT60 time of a 2.5 to 3.5 sec hall to 1.4s flat from 100hz to about 2k with a slope downwards in an approx 3000 meter3 volume. Of course using, REW and a pair of speakers rather than the sophisticated Dodecahedron spekears and acoustic mic.
Simulation shows that with the venue filled with 300 people with the new chairs should bring it down to 1.1sec or even lower. My next goal is to find a sound sytem that I deem appropriate to sound good enough for that hall to allow the owner to ascertain if he wants to spend more on the acoutsics or not. I feel the VRX he usually rents at least in my amatuer opinion is that too much sound will still bounce around and with a point source we can direct the sound to the dance floor, with a minus 3 or 6db being covering to the seated audience.

Some notes from me:
- The QSC TM30Pro is NOT a loudspeaker management system. It might be persuaded to act as one in some circumstances, though. The crossover slopes are fixed, the EQ is limited to a 6-band parametric EQ and a 30-band graphic on each output. It's certainly not ideal, but it could be done.

So here I understand its limited in its functions and parametric EQ capabilites. And of course fixed crossover slopes are not the best but still might be manageable. If my speakers have DSP would the touchmix pro be enough?

- Let's say, for a moment, that you've decided to go ahead and use the QSC desk as an LMS. You've used various outputs to drive various amps and speakers with different crossover points etc etc etc. Then, a sound engineer needs to mix a show. Will they have access to all of those settings? It would be quite easy to destroy most of the PA system just by loading a blank scene and playing some music.

So my understanding here is that there is no way to save the settings in the mixer, while a outboard DSP will have the ability to save a variety of DSP settings?

- Following all of this, there's a reason why I put all of my crossovers/limiters/EQ in the DSP in my amps: it makes sense. I can lock everything down. Someone else could turn up, connect their preferred desk etc, and everything would be fine.

So an outboard DSP is a must. This is technically not my problem, I will make my recommendations to the owner but my priority for now is to ensure a good sounding venue with a decent sound system for this one off event.

Now, if you simply wanted to use the TM30Pro to route to a few different coverage areas, that would be easy enough. It's still not ideal, but that's a better use for a device like this. Using it to configure a PA system, though, is not the intended use and there are a lot of ways it could go wrong.

Well, this is going to be for a one off event. I just want to be sure that the DSP in the touchmix is enough to provide decent sound. The speakers will be the QSC KW122 which has onboard DSP and the KS118 subs I think also do.

Finally, the Room Tuning Wizard is similar to many other dumb auto-EQs. Download Room EQ Wizard, use a measurement mic, and do it properly.

There will be a sound engineer/sound check guy on the night but I just want to be sure everything is being done properly. Are you recommending for me to use REW and use either the automatic EQ in REW or use the measurement from REW to make descisions on where to EQ? The sound check guy must have his way, I just would like to know a little more of the basics.

 

[ChrisG]

Disclaimer, I am not a sound engineer I am working on the acoustics in a wedding hall and have brought the RT60 time of a 2.5 to 3.5 sec hall to 1.4s flat from 100hz to about 2k with a slope downwards in an approx 3000 meter3 volume. Of course using, REW and a pair of speakers rather than the sophisticated Dodecahedron spekears and acoustic mic.
Simulation shows that with the venue filled with 300 people with the new chairs should bring it down to 1.1sec or even lower. My next goal is to find a sound sytem that I deem appropriate to sound good enough for that hall to allow the owner to ascertain if he wants to spend more on the acoutsics or not. I feel the VRX he usually rents at least in my amatuer opinion is that too much sound will still bounce around and with a point source we can direct the sound to the dance floor, with a minus 3 or 6db being covering to the seated audience.

The pattern control on VRX, IIRC, isn't great. Something like the RCF NX45 is likely to do better, and is easier to rig as well.

So here I understand its limited in its functions and parametric EQ capabilites. And of course fixed crossover slopes are not the best but still might be manageable. If my speakers have DSP would the touchmix pro be enough?

If the speakers have DSP, what do you actually need the TouchMix for?
A simple 2-in, 2-out parametric (or graphic) EQ will allow some tuning of the system, and it'll be considerably cheaper than the TouchMix.

So my understanding here is that there is no way to save the settings in the mixer, while a outboard DSP will have the ability to save a variety of DSP settings?

You can save settings in the mixer. The problem is that you can't protect those settings from being altered by a different operator. Your carefully calibrated processing will be open to adjustment.

Well, this is going to be for a one off event. I just want to be sure that the DSP in the touchmix is enough to provide decent sound. The speakers will be the QSC KW122 which has onboard DSP and the KS118 subs I think also do.

There will be a sound engineer/sound check guy on the night but I just want to be sure everything is being done properly. Are you recommending for me to use REW and use either the automatic EQ in REW or use the measurement from REW to make descisions on where to EQ? The sound check guy must have his way, I just would like to know a little more of the basics.

Those QSC KW112s are a little long in the tooth these days, but they'll be okay if that's all you have available. When it comes to visiting engineers, the typical setup is this:

Mixing desk => EQ (might be built into the desk, like the TouchMix) => Loudspeaker Management System (crossovers, driver EQ, etc) => Amplifiers

The QSC speakers you've mentioned have the Loudspeaker Management bit built-in, and they should sound pretty good from the get-go.

The EQ mentioned above is for a visiting engineer to adjust, to get the system working to their liking. Some engineers might want more bass, more clarity, whatever. That's theirs to play with.
If you want every engineer to run through your EQ settings, then you need another box which would sit between the mixing desk and the (active) speakers, which you can adjust and then lock down. Other engineers will still be able to play around with the EQ in whatever mixing desk they're using, but the "flat" starting point will be what you've spent time setting up.

Chris

 

[Trdat]

The pattern control on VRX, IIRC, isn't great. Something like the RCF NX45 is likely to do better, and is easier to rig as well.

After some forum research that was the consensus regarding the VRX. I just checked the RCF NX45, crossover 650 which is great and its a 15 inch. 90 by 50 is great. I just don't know if the sound engineer can organize RCF although there is a lot of it floating around in my country.

If the speakers have DSP, what do you actually need the TouchMix for?

Look, as an amatuer I thought you needed some type of outboard DSP that manages the whole thing but yeh, if you can manage enough fromt eh speakers end great. Plus, thats just the mixer they will be using anyway....

A simple 2-in, 2-out parametric (or graphic) EQ will allow some tuning of the system, and it'll be considerably cheaper than the TouchMix.

Such as? The ones in the speakers or are you recommending something else?

You can save settings in the mixer. The problem is that you can't protect those settings from being altered by a different operator. Your carefully calibrated processing will be open to adjustment.

Good to know thanks.

Those QSC KW112s are a little long in the tooth these days, but they'll be okay if that's all you have available. When it comes to visiting engineers, the typical setup is this:

Mixing desk => EQ (might be built into the desk, like the TouchMix) => Loudspeaker Management System (crossovers, driver EQ, etc) => Amplifiers

The QSC speakers you've mentioned have the Loudspeaker Management bit built-in, and they should sound pretty good from the get-go.

The EQ mentioned above is for a visiting engineer to adjust, to get the system working to their liking. Some engineers might want more bass, more clarity, whatever. That's theirs to play with.

I am relying on the sound engineer for that one off event. I will accompany him just to help with REW and other knowledge I have got from these forum. Maybe he is more than qualified, I am sure he is. I just want to make sure many of the principles that I have come to know are being used to ensure teh best results. Best case scenario is that I will be obsolete. Lol!!!

If you want every engineer to run through your EQ settings, then you need another box which would sit between the mixing desk and the (active) speakers, which you can adjust and then lock down. Other engineers will still be able to play around with the EQ in whatever mixing desk they're using, but the "flat" starting point will be what you've spent time setting up.

So for future the venue will need an advanced outboard DSP like the Xilica. But that is for future, I am just trying to ensure this round will be good enough.

 

[ocinn]

Hi, Live Systems Engineer here,

If you are only deploying a basic full-range LR pair, the mixer will be fine, as all you need is a a basic compressor/limiter and EQ.

The second you add subwoofers, fill speakers, etc.., you will want outboard DSP for routing and control, to handle crossover, delay, EQ, compression, limiting etc.... and leave the mixer free for strictly mix purposes

Disclaimer, I am not a sound engineer I am working on the acoustics in a wedding hall and have brought the RT60 time of a 2.5 to 3.5 sec hall to 1.4s flat from 100hz to about 2k with a slope downwards in an approx 3000 meter3 volume. Of course using, REW and a pair of speakers rather than the sophisticated Dodecahedron spekears and acoustic mic.
Simulation shows that with the venue filled with 300 people with the new chairs should bring it down to 1.1sec or even lower.

Well, this is going to be for a one off event. I just want to be sure that the DSP in the touchmix is enough to provide decent sound. The speakers will be the QSC KW122 which has onboard DSP and the KS118 subs I think also do.

No offense, you are approaching system design logic from a wildly overly-analytical, impractical/backwards lens.

Intelligibility is determined by the incident(direct) to reflected/ambient noise ratio. Concern over RT60, DSP filter taps, measurements and corrective EQ when you are using a pair of consumer QSC powered mains over consumer QSC subs for a one-off event is absolutely absurd.

My next goal is to find a sound sytem that I deem appropriate to sound good enough for that hall to allow the owner to ascertain if he wants to spend more on the acoutsics or not. I feel the VRX he usually rents at least in my amatuer opinion is that too much sound will still bounce around and with a point source we can direct the sound to the dance floor, with a minus 3 or 6db being covering to the seated audience.

This makes no sense.

First, and most importantly, focus on designing a system using controlled directivity sources which smoothly cover the intended listening area with minimal boundary illumination.

Hypothetically, lets look at an exaggerated, yet technically simplified (without boundary interactions) situation.

You have a venue, 2x 90Hx60V speakers, and 2x 18" subwoofers and ample time and equipment for whatever rigging arrangement you desire.

- Option 1 (right), speakers on poles over the Subs, tweeter at 7ft
- Option 2 (left), speakers flown along ceiling, at 18ft, inline delay to rear speaker, pointed down at audience, flown central subwoofers (granted you'd never do this arrangement with only 2 speakers, but I want to keep the comparison equivalent)

- Option 1 has a horrific SPL gradient, and tons of back and side-wall illumination, has problematic misalignment, and has wildly uneven subwoofer coverage
- Option 2 has a much smoother SPL gradient, less wall illumination, flawless alignment, and flawless subwoofer coverage

Due to the smoother SPL gradient, and proper alignment, and less wall illumination, option 2 will have significantly more average intelligibility and consistency across the entire audience region, regardless of the room.

In the time, energy, and money it takes you to setup your 2x tops on poles over 2x subs system, take measurements, deal with REW, design EQ filters, realize you messed up somewhere and start again, realize REW is inadequate for live sound use, purchase SMAART+an interface+professional measurement mic for $1800, start your tuning process for the 3rd time, meticulously find all the points to place acoustic treatment, tune again, your show starts, you realize you spent all of that time and it didn't translate at all now that the venue has bodies on the floor, people in the front row are complaining about it being far too loud, and people on the sides complain about no bass, and people in the back are experiencing an awful incident:reflected sound ratio and its completely unintelligible...

...I could have installed a far, far more capable system with highly optimized placements, and tuned it solely by ear, 3 times over. Not suggesting you tune by ear or deploy ridiculous inline mono delay setups, I'm just trying to prove my point that your priorities are completely misguided.

99.999% of people only care about 3 things

- hearing the audio
- not having to walk around to find a spot where they can hear the audio because of poor coverage or dominant reflections.
- good bass

Coverage (and therefore its ability to push reflections outside of audibility) is 500x more important than obsessively perfect tonality.

Here’s a system I deployed this weekend. Way way way worse RT60 than your venue. But guess what? It sounded flawless. The reason? Flawless placement to reduce wall illumination, cardioid bass to reduce room effects, and so on.

 

[Trdat]

Hi, Live Systems Engineer here,

If you are only deploying a basic full-range LR pair, the mixer will be fine, as all you need is a a basic compressor/limiter and EQ.

No, there is two KS118 which I am trying to decide if they should go cardoid in the middle(if there is space or keep it simple on the left and right of the stage. Should seated audience receive bass or not. What is the general requirment?

The second you add subwoofers, fill speakers, etc.., you will want outboard DSP for routing and control, to handle crossover, delay, EQ, compression, limiting etc.... and leave the mixer free for strictly mix purposes

Are you saying if i add the two KS118 subs that the mixer is not enough to EQ? I thought the KS118 has some DSP on the amp, is that not enough?

No offense, you are approaching system design logic from a wildly overly-analytical, impractical/backwards lens.

I am not offended, like I said it is really not my job to interere with the sound system design regardless if it is for a one off event or for future purchase however, the VRX's aren't going to provide the best system for them to be pleased with the potential of the venue maybe they are I don't know. The sound system engineer will sell or rent anything that suits him and accomodate the room to the best of his ability within the range of tools he has, I doubt he will go beyond what he can manage to ensure a good sounding room. Secondly, all the literature in the world is in English, so I can't imagine that they will be up to date with all these information that your sharing but hey best case scenario is thatat least the sound check guy on the night does manage everything.

Intelligibility is determined by the incident(direct) to reflected/ambient noise ratio.

I was severely impeded with the designers and owners choice when it came to treating the place, there was no room to move in terms of finding reflections and controling them, side walls we werent allowed to be touched and design had already been done to we had to add where we could. Yes, I used what on might call parametric acoustics but identifying bad reflections was pointless due to having the option of treating specific parts. I started after the venue was designed. But I am keen to know are you saying this point from an acoustic perspective or a sound system perspective?

Concern over RT60, DSP filter taps, measurements and corrective EQ when you are using a pair of consumer QSC powered mains over consumer QSC subs for a one-off event is absolutely absurd.

I am little confused what your gettng at here? I am not concrened about RT60 in regards to the sound system but yes, I thought filter taps was important but I am probably wrong. But if I shouldn't be worried about corrective EQ then are you saying that corrective EQ is not my priority but setting up a system with minimal boundary interference is???

This makes no sense.
First, and most importantly, focus on designing a system using controlled directivity sources which smoothly cover the intended listening area with minimal boundary illumination.

Isn't that what I proposed? Maybe I explained it in a weird way or perhaps I really don't have the concepts above board but I appreciate you laying down in simple terms. So the goal is to reduce the boundary interference with the highest SPL aimed at the dance floor and a reduced SPL smoothly covering the intended listening are to the left and right seated audience. The QSC KW122 manages a smoothly that in Ease Focus. The subs though on the right and left provide a lot of bass to the seated audience, and I am curious about that??

Hypothetically, lets look at an exaggerated, yet technically simplified (without boundary interactions) situation.

You have a venue, 2x 90Hx60V speakers, and 2x 18" subwoofers and ample time and equipment for whatever rigging arrangement you desire.

Which I dont have for this one off event(rigging equipment or ample equipment) and trying to make do with what the sound engineer can organize with his limited options which so far the best option is the QSC. Otherwise he also does have an unkown brand https://www.nextaudiogroup.com/en/product/la122a/from/80 but I know you have to see the room to know what speaker will match the venue.

- Option 1 (right), speakers on poles over the Subs, tweeter at 7ft
- Option 2 (left), speakers flown along ceiling, at 18ft, inline delay to rear speaker, pointed down at audience, flown central subwoofers (granted you'd never do this arrangement with only 2 speakers, but I want to keep the comparison equivalent)

View attachment 359067

- Option 1 has a horrific SPL gradient, and tons of back and side-wall illumination, has problematic misalignment, and has wildly uneven subwoofer coverage
- Option 2 has a much smoother SPL gradient, less wall illumination, flawless alignment, and flawless subwoofer coverage

Due to the smoother SPL gradient, and proper alignment, and less wall illumination, option 2 will have significantly more average intelligibility and consistency across the entire audience region, regardless of the room.

I understand this part and hence why I am keen to ensure that these type of apporoaches are taken by the sound engineer.

In the time, energy, and money it takes you to setup your 2x tops on poles over 2x subs system, take measurements, deal with REW, design EQ filters, realize you messed up somewhere and start again, realize REW is inadequate for live sound use, purchase SMAART+an interface+professional measurement mic for $1800,

Great to know about SMART however for this one off event, I doubt I can convince the owner to purchase something like that. But I can check if the sound engineer uses SMART or asks what he uses

start your tuning process for the 3rd time, meticulously find all the points to place acoustic treatment, tune again, your show starts, you realize you spent all of that time and it didn't translate at all now that the venue has bodies on the floor, people in the front row are complaining about it being far too loud, and people on the sides complain about no bass, and people in the back are experiencing an awful incident:reflected sound ratio and its completely unintelligible...

Do the people on the sides want bass? Maybe they do but reduced SPL I am presuming?

...I could have installed a far, far more capable system with highly optimized placements, and tuned it solely by ear, 3 times over. Not suggesting you tune by ear or deploy ridiculous inline mono delay setups, I'm just trying to prove my point that your priorities are completely misguided.

I am confused here a little again, probably because I can't understand what is the optimized placement or perhaps why the QSC is so wrong? Are you saying hanging speakers would be a much better option. Where am I exactly misguided? Not being rude just trying to ask the right questions to get my had around it.

Coverage (and therefore its ability to push reflections outside of audibility) is 500x more important than obsessively perfect tonality.

Thats right which is what I am trying to achieve with a simple point source but if your saying that is wrong, I need to understand how say a 90 by 50 speaker will be so bad? Or for arguments say the conical horn of the QSC of 75 degrees.

This is the room. The red is the treatment minus the panels on the side ceilings haven't got there yet, this was just a simulation.

Like I said, I am not getting paid for this part of the job. In future, I will recommend a sound system designer to design the system he purchases but for now, I just want a one off sound system that can do the job with the imposing limitations.

 

[ocinn]

No, there is two KS118 which I am trying to decide if they should go cardioid in the middle(if there is space or keep it simple on the left and right of the stage. Should seated audience receive bass or not. What is the general requirement?

Sorry, I should have been more clear, I consider the subs and the mains to be the "basic LR pair” since the QSCs include hi-pass/low-pass true 2 way crossover.

Even if they didn’t, it may be a bit inconvenient, but you can achieve a basic 2 way crossover in the mixer. I wouldn’t go further than that though.

I am little confused what your getting at here? I am not concerned about RT60 in regards to the sound system but yes, I thought filter taps was important but I am probably wrong. But if I shouldn't be worried about corrective EQ then are you saying that corrective EQ is not my priority but setting up a system with minimal boundary interference is???

First off, you won't be using FIR due to its latency, so taps (or lack thereof) doesn't matter. I'm saying that placement is far more important than perfect corrective EQ. With experience, you can tune small systems like this by ear perfectly in 15mins.

Do the people on the sides want bass? Maybe they do but reduced SPL I am presuming?

They want equivalent tonality. Bass coverage should "falloff" equal to the mains.

I am confused here a little again, probably because I can't understand what is the optimized placement or perhaps why the QSC is so wrong? Are you saying hanging speakers would be a much better option. Where am I exactly misguided? Not being rude just trying to ask the right questions to get my had around it.

I need to understand how say a 90 by 50 speaker will be so bad? Or for arguments say the conical horn of the QSC of 75 degrees.

Two point source speakers placed over subwoofers on standard height poles, will be far too low, and force the subs apart far too wide. It will be painfully loud in the front, with poor coverage in the rear, and no bass outside of the centerline. They will also have quite poor boundary illumination which is why most people's first thought goes to "treatment" and not considering their placement is just awful. These are shown in my simulation.

If you are truly stuck with that gear, I'd get the tallest stands you can, some pole-mount angle/tilt adapters, and place the subwoofers stacked vertically.

Are you saying hanging speakers would be a much better option.

Yes, well, moreso that getting creative with placement will provide a result far nicer than hyper-focusing on room treatment an measurements and tuning.

The venue plan looks nothing like what I imagined actually, I was envisioning one single apace, not 3 separate areas.

If you could please reply with the dimensions of the "sides" and the central dancefloor that would be fantastic.

 

[Trdat]

Sorry, I should have been more clear, I consider the subs and the mains to be the "basic LR pair” since the QSCs include hi-pass/low-pass true 2 way crossover.

Now I understand that your point is based on the system being too simple. Great thanks. I think thats is were my confusion was and I admit that I thought that simple system such as this might be the best option however it seems too simple thanks for pointing that out.

First off, you won't be using FIR due to its latency, so taps (or lack thereof) doesn't matter. I'm saying that placement is far more important than perfect corrective EQ. With experience, you can tune small systems like this by ear perfectly in 15mins.

This is good news to, the sound check guy should bring out the potential of the system even thought its not so good in the first place, thats if i go with the QSC option. I am now thinking if we can get speakers higher maybe a different option might work better, but for now lets not comlicate things.

They want equivalent tonality. Bass coverage should "falloff" equal to the mains.

Thanks for this, I didn't know this basic requirement.

Two point source speakers placed over subwoofers on standard height poles, will be far too low, and force the subs apart far too wide. It will be painfully loud in the front, with poor coverage in the rear, and no bass outside of the centerline. They will also have quite poor boundary illumination which is why most people's first thought goes to "treatment" and not considering their placement is just awful. These are shown in my simulation.

I get what your saying here and I am also working towards the same goal, I am simulating in Ease Focus to achieve similar results however I don't think we can hang speakers at least for this one off event, in future perhaps so. I have to make do with what we got.

If you are truly stuck with that gear, I'd get the tallest stands you can, some pole-mount angle/tilt adapters, and place the subwoofers stacked vertically.

Let me find out if there is a way to have tilt adapter for the mains. Subs stacked vertically in cardoid arrangement? There is only two subs, so stacked vertically in the middle rather than taking them out wide like you said which will cause boundary illumination?

Yes, well, moreso that getting creative with placement will provide a result far nicer than hyper-focusing on room treatment an measurements and tuning.

It took me a while to fully understand what you were saying and probably vice versa, room treatment for now is over I have done my job and am aware fully aware that creative placement is key hence why I am going above and beyond my part of the job to ensure that the sound system will sound good. But, I think your issue was that my one time system design is so dodgy that it really isn't going to complament my acoustics. That I didn't know but there is limitations and the QSC might be better than the one VRX pointed down or will it? Tuning, I will leave for sound check guy and room treatment is over for now.

If you could please reply with the dimensions of the "sides" and the central dancefloor that would be fantastic.

Basically, front to back is 17 meters and side to side is 23 meters. The dance floor ceiling is about 9 meters while the seated area ceiling tilts upwards towards the back starting from around 5 meters heading up to 7 meters. So the two left and right side sections will be 17 meters front to back and about 7 meters from side to side each side that is. The dance floor will also be 7 meters side to side and 17 meters front to back minus the stage. Don't worry about the table and chairs beside the stage that is just the simulation, if there happens to be a tables there on that night I hope the sound check guy will add some filers as I think we can get 4 of the same mains. I know that comlicated things but I will entrust the sound check guy.

 

[ocinn]

Subs stacked vertically in cardoid arrangement? There is only two subs, so stacked vertically in the middle rather than taking them out wide like you said which will cause boundary illumination?

You shouldn’t do cardioid with only two subwoofers. You want a 2:1 (3 boxes) or 3:1 (4 boxes) ratio of forward:cardioid. Any less and you are sacrificing efficiency.

You could do an endfire with only two boxes, to achieve a similar effect but without the efficiency drawback, but unless the sound technician is intimately familiar with it and has SMAART to tune the spacing and delay, and can sort out how to do that in the mixer alone, I wouldn’t bother.

The image in my first reply, of the show I did from last weekend, I used endfire boxes to control the pattern. Which is why the simulation has fantastic forward directivity.

You cannot control for wall illumination with subwoofers. The issue with widely spaced subwoofers is that they will create a cancellation null once you are off of the center axis. In live sound this is called the “power alley” (bass is only strong in the center axis, and rapidly falls off outside of it.

The reason I suggest a vertical stack vs horizontal is your subwoofer directivity will he controlled in the “long axis” (I.e a vertically stacked subwoofer array will have wider horizontal dispersion and narrower vertical (which is good). Side by side will be the opposite (not good, since you want very wide horizontal dispersion to ensure that some bass gets to the seated areas.

might be better than the one VRX pointed down or will it?

VRX is not a great box, imo, and they are also designed to be deployed with no less than 3 per side.

There are plenty of ways to get that space working very well with high budget for permanent install, but you will struggle with the system you are doing for this one off event.

 

[Trdat]

You could do an endfire with only two boxes, to achieve a similar effect but without the efficiency drawback, but unless the sound technician is intimately familiar with it and has SMAART to tune the spacing and delay, and can sort out how to do that in the mixer alone, I wouldn’t bother.

Great advice thanks

You cannot control for wall illumination with subwoofers. The issue with widely spaced subwoofers is that they will create a cancellation null once you are off of the center axis. In live sound this is called the “power alley” (bass is only strong in the center axis, and rapidly falls off outside of it.

So are you where are you suggesting the vertically stacked two subwoofers go? In the middle? I am just asking out of curiousity, as now there are two other options below with 4 subs. I am just thinking if there was only two and I vertically stacked them where is the bes tplacement?

The reason I suggest a vertical stack vs horizontal is your subwoofer directivity will he controlled in the “long axis” (I.e a vertically stacked subwoofer array will have wider horizontal dispersion and narrower vertical (which is good). Side by side will be the opposite (not good, since you want very wide horizontal dispersion to ensure that some bass gets to the seated areas.

Helps a lot, thanks.

VRX is not a great box, imo, and they are also designed to be deployed with no less than 3 per side.

Hopefully, we can do better with the QSC, and if we dont there are other options for renting for another event to get an idea what best but only from that one particular supplier.

There are plenty of ways to get that space working very well with high budget for permanent install, but you will struggle with the system you are doing for this one off event.

Yes, hence why I will opt for a sound system designer and probably get in touch with you when the time comes, however, I am stuck with this now.

The other option for subs is 4 each of these

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www.nextaudiogroup.com

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products.dynacord.com

I am presuming that these will be better than 2 QSC subs. But we still can't hang and they will be on the floor for this event.

Any simple advice on how to stack or what array them would be greatly appreciated. I will simulate in Ease Focus but any help would get me started.

 

[ocinn]

I am just thinking if there was only two and I vertically stacked them where is the bes tplacement?

If it doesn’t obscure sight lines (I.e if the “stage” is elevated, so the stacked subs wouldn't block the view of the DJ/Performer/etc...) directly in the center between the mains (on stands).

If for this particular event your system is set in stone, and will consist of 2x pole mount speakers and 2x 18” subwoofers, this is how I would arrange them.

- Mains 4m apart, center to center

- Mains toed OUT 12deg (my sim model uses narrower directivity box, and I'm too lazy to draw a new venue plan in another software with a 75conical model), thus the KW112 will fill in that gap in the center of the dancefloor and have more coverage to the wings (you can do toe-out and spacing to taste, depending on how much you want to prioritize dancefloor SPL vs the seated areas.

I.E. Wide and toed in would highlight the dancefloor more, and narrow spacing and toed out would supply more to the seated zones.

- Mains 2.8m high (to center of tweeter), higher is better of course, but at least here in the USA, its hard to find consumer stands more than 8ft (2.4m) tall. If you go higher than this you may want to get the angle adapters i mentioned in an earlier comment. The higher you go, the more tilt down you need (but you also get smoother SPL gradient due to smaller deltas in distance from front to rear).

- Subwoofers, central, 1m (front to front) end-fire, 2.5ms delay on front box.

- Mains may or may not need to be delayed to align to the front (2.5ms) delayed box. No way to predict this since placement relative to subs will vary, and I don't know the internal latency of the boxes.

You can easily do this by ear however. Mute the rear subwoofer, Play a loop of a kick drum. Delay the mains until the kickdrum sounds the tightest. If delaying the mains makes it worse, then zero the delay of the mains, and instead delay the front subwoofer more. If you ended up delaying the front subwoofer, subtract 2.5ms from that figure and that is your correct rear subwoofer delay value.

If you use the 4 subwoofers, you can either do a 2x2 "cube" in the center, or you can do a 2 front, 2 rear end fire (i.e. doubling the width of what I show in the image above)

If you don't want to do endfire, and you cant have the vertical height of the 2x2, you can arrange them in a 4-wide horizontal line, and either delay the outer two by 2ms or so, or you can physically move the outer two backwards (making an arc-shape). Both do the same thing, which is to beamsteer the response, less "throw" and more "width".

2ms delay or 0.7m pushback (0.7m is 2ms delay due to speed of sound, but they operate a bit differently due to directivity physics. You can also do combos of milder steps of both, like 1ms delay and 0.35m pushback, or anything you please):

 

[Trdat]

If it doesn’t obscure sight lines (I.e if the “stage” is elevated, so the stacked subs wouldn't block the view of the DJ/Performer/etc...) directly in the center between the mains (on stands).

If for this particular event your system is set in stone, and will consist of 2x pole mount speakers and 2x 18” subwoofers, this is how I would arrange them.

- Mains 4m apart, center to center

- Mains toed OUT 12deg (my sim model uses narrower directivity box, and I'm too lazy to draw a new venue plan in another software with a 75conical model), thus the KW112 will fill in that gap in the center of the dancefloor and have more coverage to the wings (you can do toe-out and spacing to taste, depending on how much you want to prioritize dancefloor SPL vs the seated areas.

I.E. Wide and toed in would highlight the dancefloor more, and narrow spacing and toed out would supply more to the seated zones.

- Mains 2.8m high (to center of tweeter), higher is better of course, but at least here in the USA, its hard to find consumer stands more than 8ft (2.4m) tall. If you go higher than this you may want to get the angle adapters i mentioned in an earlier comment. The higher you go, the more tilt down you need (but you also get smoother SPL gradient due to smaller deltas in distance from front to rear).

- Subwoofers, central, 1m (front to front) end-fire, 2.5ms delay on front box.

- Mains may or may not need to be delayed to align to the front (2.5ms) delayed box. No way to predict this since placement relative to subs will vary, and I don't know the internal latency of the boxes.

You can easily do this by ear however. Mute the rear subwoofer, Play a loop of a kick drum. Delay the mains until the kickdrum sounds the tightest. If delaying the mains makes it worse, then zero the delay of the mains, and instead delay the front subwoofer more. If you ended up delaying the front subwoofer, subtract 2.5ms from that figure and that is your correct rear subwoofer delay value.

If you use the 4 subwoofers, you can either do a 2x2 "cube" in the center, or you can do a 2 front, 2 rear end fire (i.e. doubling the width of what I show in the image above)

If you don't want to do endfire, and you cant have the vertical height of the 2x2, you can arrange them in a 4-wide horizontal line, and either delay the outer two by 2ms or so, or you can physically move the outer two backwards (making an arc-shape). Both do the same thing, which is to beamsteer the response, less "throw" and more "width".

2ms delay or 0.7m pushback (0.7m is 2ms delay due to speed of sound, but they operate a bit differently due to directivity physics. You can also do combos of milder steps of both, like 1ms delay and 0.35m pushback, or anything you please):

This is legendary stuff, I really appreaciate it. I didn't even know where to start with basic sub configurations, just new about the power alley but nothing really to solve it. I will try and simulate more in Ease to get an idea but you have given me heaps here, if anything what you got is somethng I can use eyes closed. I just have to check what the owner would allow, if I can get use your similation photo(above) and perhaps a few more from Ease I can convince him and have decent sub array. Thanks again.