Are 24 x T60-LAB15s Enough? ;)

[Keryn O'Shea]

How many ohms do we use? 6 ohms for the LAB12 driver? Do we add 2 ohms for the cab? So do we count 8 ohms total for amp load?

Yes mate.

Does anyone know what the ohm rating for the DR280s is?

Nominal Impedance with the 3012HO and 2x Series wired NSD2005s would be 5.33ohms I think. Do you have a source for the NSD2005s? I ask as of this info: https://billfitzmaurice.info/forum/view ... hp?t=25250.

[Levi]

@Keryn

Awesome, thanks! 8 ohms it is!

Thanks for pointing that out! I was just going off of what was listed in the plans. I never checked availability.

So I guess we'd use the 3012HO and 2 x F151M-8.

Unless there is an equivalent for the BMS H4552ND? We are leaning towards bi-amping the DR280s, and getting that lowest 1kHz crossover seems like the way to go.

[Seth]

Tuning

Okay! I finally got our tuning/limiting info!

Information wise, that's a good start. Better than nothing, for sure. You guys didn't happen to use a measurement microphone to take any measurements of the system response or have the Driverack auto tune, did you? Judging by the EQ plot, I'm going to guess "no", but still worth the ask. If not, was it just tuned by ear or was the EQ adjusted just based on intuition? Was there a method to the madness? Just trying to get a feel for where to start pumping you with info.

Once constructed, is there any possible way to set the subs up in a large open area somewhere, prior to the event?

[Seth]

Also, I noticed a $30 price increase for the LaVoce SSF122.50L on PartExpress. That adds up quick when so many drivers are in play. My guess is you'd be able to get that cost back down with a "large quantity" order. Also, they're currently out of stock without a quote for when they're expected to be back in stock, which I've noticed they do when they can. Definitely worth some investigation, perhaps a telephone call.

[Levi]

@Seth

We did use a microphone!

We did not use the Driverack auto tune.

To tune the system, we used REW software on a laptop through a Midas 32 console, with a low/high split using matrix sends from the Midas.

We used the Midas parametric EQs and compressor/limiters at -4db on the sends.

We set the crossovers to match the Driverack settings, with an additional highpass set at 18 Hz.

We ran the REW tests, as well as the Midas white and pink noise generators.

Overall, we had very few EQ changes.

We did some power shading with two of the Omni-Tops that were turned in on axis for center fills.

Again, we had a 56’ span between arrays. The arrays were in phase. We were far from clipping anywhere in the chain. In the end, our limiting factor was rattling in some of the T60s.

We finished tuning by ear using a wifi rig and an ipad controlling the Midas console remotely from FOH with an RTA on the iPad.

Also, we used the Midas analogue preamps for left/right channels from the DJ mixer because those pesky little mp3s need all the love they can get!

And yes, we will likely have a large open area to do a test run prior to the event. It won’t be as open as the desert, but hopefully good enough for tinkering.




Also, thanks for the update on pricing and availability! We will definitely be on top of that!

[Seth]

@Seth

We did use a microphone!

We did not use the Driverack auto tune.

To tune the system, we...

Do I understand correctly, that you had crossover filters engaged in both the M32 and Driverack simultaneously?

Do you have access to any of the measurement data? A screenshot or saved jpg RTA/response graphs, or anything like that, which would show the systems final tuned response?

Some people tune the system flat, +/-3dB on RTA and EQ the source channel to taste. And others tune the system with the lows bumped up and the highs slightly attenuated, which requires little to no source channel EQ for playback of commercial recordings. If you don't have the REW graphs, can you tell me a little about the target response the system was tuned to?

Do you happen to have the M32 configuration file saved to your PC? If so, you can email the file to me and I'd be happy to look everything over.


You've hinted a few times for some input and advice for effective deployment of the subs and it's great that you'll be able to try different configurations before it's actually game time and the pressure is on to get it all up and going. I like the vision of them all lined up and people dancing on them, however I'm afraid that's not likely to be the optimum configuration. To be really straight up with you, I have zero experience setting up a system as large as we're talking. But, there are some general audio principals that if they hold true (and they should) could make one long single high row of subwoofers a poor choice. And it's all about creating even coverage over the listening area with as few hot and cold areas, power alleys and power valleys as possible. It's a weird but simple thing, the soundwaves that are emitted from one side of the same speaker cancel out sound waves emitted from the other side of the same speaker at frequencies that are 1/2 wavelength of the cone diameter, or in the case of horns, the mouth width. Crazy right? So when you make a long line of subwoofers, they all interact with each other causing constructive summation, louder in some areas of the listening space and destructive summation, deeply reduced SPL in other areas of the listening space and those hot and cold spots are ever changing depending on frequency. It really is quite a bumblefuck with sound from here getting cancelled by sound from over there, but again getting boosted in another area from sound from a different cab than previous. Sound is definitely not as simple as the light emitted from a flashlight. Sound does some nutty stuff that doesn't make a whole lot of sense at first take.

These two articles will explain a little better, but I think your premium deployment solution will be six foot eight inch high stacks of four 20" T60's (or five foot stacks of three if 4 cabs is unreasonably too tall for whatever reason), with the stacks arranged in a curve with each stack delayed to create the most even coverage throughout the intended listening space. Give these a read at your own leisure.

A Practical Guide To Good Bass: Part 1
A Practical Guide To Good Bass: Part 2

If you still want the ground level approachable DJ booth, make the sub array the center stage attraction with set design and lighting, put the booth off to one side and something else on the other side to balance the visual experience. Perhaps a slightly elevated dance floor with the same look as the booth or a barstool spectators lounge. Just a couple thoughts. I love the music, but I prefer to sit, people watch, and soak in the experience. I'm not so much into dancing all night long. I've got a few friends that are the same way.

[Keryn O'Shea]

Man.. If only I was closer, I'd love to witness the build and set-up, this is going to be a wicked system!

[Seth]

I would do all of the systems primary crossover, EQ, and limiting in the Driverack and not do any of it in the M32 except for small incidental tweaks here and there, little things. I'm not sure if you have already or not, but if you connect the ethernet port on the back of the PA2 to a router you can operate it from a PC or tablet, the GUI is far more intuitive, way easier, and quicker than fumbling through the menus and functions from the front of the unit.

Not only is it the primary function of the Driverack to handle these tasks, if your M32 takes a dump, you can just plug your DJ controller (or playlist on your phone for that matter) directly into the Driverack and you'll be all set to go on a tuned system. You guys are brave. I wouldn't even think to bring an expensive mixer with motorized slides out into those conditions unless it was 100% enclosed and vented with filtered air. Although, if you guys are using the M32C, thumbs up, good choice.

Amplifiers: There's a million ways to go. I personally like slim 1RU amplifiers with 4 channels. Powering that many cabs, it would definitely save on rack space. With two cabs per channel, you'd be able to power 32 subs with only 4 amplifiers occupying only 4RU worth of space in the amp rack, the same space of two standard 2 channel amps. Something like the Admark K410 would be more than enough power and capable of ample thermal dissipation. K410 on ebay I'd offer these guys $850 per unit in the quantity you require, 4-6ish and see if they counter or just turn their nose up. Would be great to get 'em for less than $1k per unit. But really, they're a decent deal at the price listed. I've heard rumors that you can save some bucks contacting and dealing with the factory directly.

Admark has been proving itself, gaining favor, and showing as a reliable budget alternative in some circles (Reggae and EDM DJ's/sound companies) The units seem to compare well to ultra high dollar Powersoft amplifiers in power output, compact size, and construction quality.

Although, if you already have a line on more of the amplifiers you're already using, bought second hand or borrowed, you'd be dollars ahead to just continue the path you're on and deal with the weight and additional bulk.

If you went with something a little more traditional from a well know brand like the Crown XLS2502, you'd be a tiny, insignificant amount of power short of maximum the cabs will take. But, the amp could potentially be driven to it's maximum potential output and the total cost to drive 32 cabs is higher. Using the maximum output isn't usually a problem, but when cooling in a hotter than normal environment, it makes sense to me to have a little extra power rating and run the amps at a fraction of their designed thermal dissipation capability. However, these points are purely based on supposition and logic. So, take it for what it's worth. I haven't personally run any of them through rigorous testing. Maybe they'd all be fine out there in the desert heat, no matter what. Who knows?

Back in the day, power conditioners were in every rack and seemed like it was standard equipment. Back in the day, the electronics were much more fussy about power than todays class D offerings. But, I am curious what you guys are using for power. What size generator do you guys use? Is it an inverter generator, a standard construction style generator, an RV style genset, or do you guys rent a high end, diesel sipp'n, ultra quiet, commercial genset trailer?

[Levi]

@Keryn

We wish you were here, too! It will be quite the journey, and the help would be much appreciated!

Side note. We had a sizable Aussie contingency at our neighbor’s camp last year. Like 40-50 or so. I think most of them live in the Sydney area. They organize a regional burn down there in the jungle somewhere. They are taking this year off from the Nevada event, but maybe they’ll be back next year. You might be able to connect with them and see what all the fuss is about. I think they call themselves the Fan Club Collective.





@Seth

No, they were not engaged simultaneously. The Midas was primary (M32LiveR), and the Driverack was backup. Both had the same settings, though.

Alas, we do not have any RTA screenshots! Silly, I know. But sometimes, especially at the end of the week, a guy feels lucky just to have made it out alive! This time around, though, we will do everything right. And we’re even talking about taking the microphone setup to the other sound systems to measure how they are doing their tuning!

Regarding the target response question, do you have anything specific in mind? We basically just tried to get as loud as we could while still being “clean”. Before the damaged T60s started rattling. Generally speaking, we targeted the ISO 226/Fletcher Munson as a basis.

About the M32 config file…Sorry man, we screwed up and didn’t save it! Our excuse? Last year was especially hard. You may have heard, it poured down rain out there, which apparently only happens once in a century or more. Gnarly stuff! People were running Lord of the Flies scenarios!!!

Interesting point about the configuration options! And yes, sound physics are crazy for me to wrap my head around… Bumblefuck indeed! That said, it seems like there may be a fantastic solution from those links that will allow us to get the best of both worlds!

“Beamforming”!!!

If we can “beamform” with the ground-stacked single row of subs in a straight line, as is shown in Figure 15...

https://www.prosoundweb.com/a-practical ... -arrays/4/

…We’d just need to be sure we have the equipment to introduce adequate delays, yes?

In Figure 15 they have 12 total subs, which means a 12 millisecond delay on the outermost pair. So if we had 32, we’d need the ability to do a crazy amount of delay, correct? Maybe even up to a full second or something? Not sure what that math works out to. Any ideas?

And also we could not do any more than one sub per channel, correct? Because if we have 2 subs per channel, we can’t get individualized delays for each sub?

We would prefer the centered single DJ booth option. But if we can’t figure out the beamforming solution, the pair of structures hugging each side of the big ole sub wall seems like a great option! Thanks! Side note, we plan to have a bar, chair-height platforms, and daybeds tastefully scattered throughout the dance floor. That way, folks can pick their own adventure and get great quality sound anywhere they go! Dance, drink, chat, lounge, whatever! And soak up some nice bass while they’re at it!

No worries, we are on the same page. We have an air-conditioned, air-filtered space that is out of the elements to house all the fancy expensive stuff. And because the amps and the M32 are well-protected there, it’s not a big deal for us to continue using it as a primary.

Thanks for the lead on amps! Right now, they are shaping up to be the most expensive part of this new system, so getting a good deal on quality equipment would be absolutely fantastic! We will definitely do a deep dive on the K410s!

For power, yes!!! We will have the high end, diesel sipp'n, ultra quiet, commercial genny. Specifically, we will rent a 70 kva generator. Not sure on the brand. We usually only find out when we pick it up.

Also, we are lucky enough now to have slowly purchased all of our distribution. (Thank you government auctions!) So that’s nice. And now, we can get the maximum amount of juice out of that size of genny, which I think is around 150 amps per phase at 120v. Our main distro box can handle up to 400 amps per phase at 120v. So 1,200 amps altogether. Whoa!!! The point is, we have plenty of headroom for sound and all the other things we need to power, including the neighbors!

[Keryn O'Shea]

I personally like slim 1RU amplifiers with 4 channels.

Seth, did you end up receiving the one you found online?

We wish you were here, too! It will be quite the journey, and the help would be much appreciated!

I'd be there with bells on.. and pair of melded 280s for your lower cabs to save your build time!

..I think they call themselves the Fan Club Collective.

Sweet, thank you

[Seth]

This time around, though, we will do everything right.

Literally laughing outload. I have no idea how many times I've said just that! Hahaha I haven't been doing this stuff as long as some of the guys here. I've still never had a gig go entirely as planned, perfect without a hitch. Seems like there's always something. Early on, and even still to this day, there's so much going on it's difficult to have full capacity and attention available to sort out any one specific task. That's why it's so valuable to have a day or two to set the system up, iron out issues, and get the bulk of the settings set and tuning tuned without any time constraints. If you can work all that out ahead of time, you'll be miles ahead come game day.

And we’re even talking about taking the microphone setup to the other sound systems to measure how they are doing their tuning!

I'm not sure how well a song request for pink noise will go over. But, it doesn't hurt to try and ask!

If they're not playing pink noise or you don't have a FFT analyzer (e.g. SMAART (expensive) or Open Sound Meter (free)) plugged into their system pre EQ as a reference signal you won't get any useful and usable information.

Who knows, maybe just ask them. Maybe they'll tell or show you? Or, maybe they will put some pink noise on early some not busy morning?

Regarding the target response question, do you have anything specific in mind?

I searched for years for an answer to that question and this is what I found (orange trace). I use it and I like the way it sounds. There are other target response curves out there, but they're all somewhat similar in the amount of bottom end response being 12-15dB above the midrange, they just differ a bit in what frequency the increase starts. The autotune curve in the Driverack is similar too.

I've got a specific method I recommend to achieving a response curve like the one pictured, but we'll save that conversation for later.

Do you remember if your curve resembled this target response curve at all?

About the M32 config file…Sorry man, we screwed up and didn’t save it!

No worries. I've done the same many times. I still don't save as much/often as I should.

Interesting point about the configuration options! And yes, sound physics are crazy for me to wrap my head around… Bumblefuck indeed! That said, it seems like there may be a fantastic solution from those links that will allow us to get the best of both worlds!

“Beamforming”!!!

If we can “beamform” with the ground-stacked single row of subs in a straight line, as is shown in Figure 15...

https://www.prosoundweb.com/a-practical ... -arrays/4/

I'm really impressed how quickly you're soaking all this up. I couldn't say whether the single long array would be good or bad tuned like you're talking about. But, it may be worth checking out some of the modeling software these other guys use. One modeling software brand is mentioned in the video below. I've honestly not had the need yet to go there myself.

…We’d just need to be sure we have the equipment to introduce adequate delays, yes?

You might fact check me on the following configuration. However, I'm fairly certain it will provide 16 individual outputs, each with it's own delay adjustable from 0.3 to 500ms.

If you follow my advice about having the Driverack do the bulk of the signal processing, you can run a patch from the Driverack Sub Out back into an input on your M32. Since you're not running a stage full of instruments and microphones you should have a ton of channels available. You can use any specific number of channel strips, but I'd personally opt to use channels 17-32 so they're off the beaten path and out of the way. I know your board only has 16 physical inputs onboard and that's okay, you can use any available input. What you'd want to do is make the source for every single channel from 17-32 use that specific input as it's source (orange arrow below). Each channel has a time delay option, adjusted in the config tab for each individual channel (green arrow). Get one of these rack mountable Ultranet compatible output units, Midas DN4816-O. In the Routing Tab (blue arrow) select the Ultranet tab (grey arrow in the next pic). In the dropdown (yellow arrow) select "Pre EQ" and scroll over to the Direct Chanel Output channels and route them to 1-16. In the second pic it shows channels 17-32 routed to Ultranet outputs 1-16 and it's tapped after the delay but prior to EQ in the signal flow. This will eliminate any inadvertent EQ changes on any of those individual channels from having any effect on the output (EQ adjustments made to the DJ Controller channel strip and/or Main LR strip will still have an effect) and the channel faders for 17-32 will have no effect on Ultranet output's 1-16 either, so it wont matter if they get bumped or fondled. In the LR Main tab (white arrow, third pic) of each 17-32 channel strip, deselect the Main Stereo LR option (pink arrow), this will eliminate the possibility of the signal getting fed back into the main mix should any of the attenuator sliders get bumped up which would cause a massive feedback loop. Now you have 16 adjustable delays and all 16 signals get to the amp rack over a single inexpensive shielded CAT5e network cable. Maybe patch the Mids/Highs signal from the Driverack back into a mixer input too and sacrifice one or two of those Ultranet outputs to also run the tops signal in the network cable to the amp rack too.

In Figure 15 they have 12 total subs, which means a 12 millisecond delay on the outermost pair. So if we had 32, we’d need the ability to do a crazy amount of delay, correct? Maybe even up to a full second or something? Not sure what that math works out to. Any ideas?

I know it would not need a crazy amount like that. However, I honestly don't know what the amounts would be. Modeling software would be the way to find out.

And also we could not do any more than one sub per channel, correct? Because if we have 2 subs per channel, we can’t get individualized delays for each sub?

The same delay is used twice, once on each side of center. So, if the 4th cab from center on the left and the 4th cab from center on the right both need 15ms delay, you'd simply daisy chain from the amp to the one on the left then also to the corresponding one on the other side of center.

I'd like to urge you to stay true to statement you made in the original post, "So this time around, we’d like to start with optimal sound quality, and then design the aesthetics around that. Instead of the other way around like we've always done!" and not get too attached to the vision of them all lined up. I honestly don't think the plan to run them in a long flat single level array is going to be your optimum solution. But, I've been wrong many times before, will be wrong many more times to come, and this could be the next one. It could be downright amazing!

Here's another excellent piece of learning material, definitely put your headphones on for this.

For power, yes!!! We will have the high end, diesel sipp'n, ultra quiet, commercial genny. Specifically, we will rent a 70 kva generator. Not sure on the brand. We usually only find out when we pick it up.

Also, we are lucky enough now to have slowly purchased all of our distribution. (Thank you government auctions!) So that’s nice. And now, we can get the maximum amount of juice out of that size of genny, which I think is around 150 amps per phase at 120v. Our main distro box can handle up to 400 amps per phase at 120v. So 1,200 amps altogether. Whoa!!! The point is, we have plenty of headroom for sound and all the other things we need to power, including the neighbors!

Too awesome. I love that this is your power situation! Perfect.

[Seth]

I personally like slim 1RU amplifiers with 4 channels.

Seth, did you end up receiving the one you found online?

I did. I got two actually. But, haven't had the opportunity to give them any strenuous testing yet.

I got the Sound Town ST-UPDM4C which is rated 4 x 800W RMS at 8Ω. With case dimensions very similar to that of a Driverack, it's surprisingly compact and feels well constructed based on how it feels in the hand. It's definitely not an empty metal box like some class D amps feel like. It feels substantial. But, that doesn't mean shit if it doesn't put the numbers out reliably.

I haven't been able to find any evidence of the Sound Town amp getting any real professional use out in the world and I haven't even verified open circuit voltage yet, so I can't recommend it for something like this threads particular use. All signs look promising though. I chuckle to myself a little when I think about this one little amp potentially powering your four huge T48's and pair of DR280's powerfully, cleanly, and efficiently to their limits. That would be great!

I also ended up purchasing an Admark AD-430, rated 4 x 3000W RMS at 8Ω. It's way more power than I need, but I came across a deal I couldn't pass up. Even though it's only a 1RU amp, it's a LARGE 1RU amp, taking up nearly all the available mounting depth a standard rack has available. And at 27 pounds, it's not particularly light nor heavy, but it also feels heavy for it's size. Four of these in a compact 4RU rack would be deceivingly heavy. Not altogether unmanageable though.

The Admark is getting used professionally and I haven't heard/read anything negative about them yet. Even though I haven't flogged the one I got, I'm comfortable making the recommendation. However, as always, caveat emptor.

[Seth]

Here's the (free) predictive software that Dave Rat mentioned he was using in his video.

L-Acoustics Soundvision

[Keryn O'Shea]

..I'm fairly certain it will provide 16 individual outputs, each with it's own delay adjustable from 0.3 to 500ms..

..if the 4th cab from center on the left and the 4th cab from center on the right both need 15ms delay, you'd simply daisy chain from the amp to the one on the left then also to the corresponding one on the other side of center..

[Seth]

Ha! Thanks Keryn