What mains do you use?

ACTSTech

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Nov 13, 2019
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USA
I'm also feeling that there's probably a good amount of politics going on with the decision making by management.
Since you did a demo with what I'm assuming are the QSCs on sticks, would they be open to hearing other demos by local distributors?

Also, how are you going to try and convince them of improved acoustics? Maybe you could rent a couple legs and hang them at 45s in the back of the room so they can hear what it's like to add some absorption?
Actually, we don't own QSC speakers. The group has Fulcrum Acoustic CX12s that they brought from their old home. I hung them on scaffolding roughly where they might be. I didn't bother to tune the room, just unleashed them as is because I didn't want to waste my time. The front 3rd of the house, empty as it is, was actually decent. The middle 3rd was muddy, the back 3rd was a badly mixed high school dance. The first comment was about the bounce off the balcony which they actually understood. The second was "Boy, imagine that if we could get a few drivers to match those speakers..." Overall, though, it went better than I expected.

They're not against purchasing, but there is a limited budget. And I'm not totally dissatisfied with the current speakers, they just aren't what the room needs for the moment. There's plenty of room on the amplifier for more, but I explained that more isn't always better, and I think they're understanding now. Looking at pdf drawings and listening to "experts" sometimes isn't as good as actually hearing and experiencing.

Now, the demos by local distributors... That's like finding a leprechaun riding a unicorn around here, at least reputable ones.
 

macsound

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Jun 15, 2018
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San Francisco, CA
From personal use, Fulcrum Acoustic speakers can sound amazing, but not if you don't apply the recommended DSP. Did you have that?
https://www.fulcrum-acoustic.com/support/processor-configurations/
I've never tried running them without the DSP but from my understanding based on how they're designed to use the DSP, they sound awful without it.

Also you mentioned the room is 80' deep. Sounds relies on physics and since you mentioned the front 3rd sounding decent, I'd imagine that's about the maximum usable throw of this particular cabinet and you'd be looking at adding delay speakers to cover the additional depth.
 

ACTSTech

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Nov 13, 2019
Location
USA
From personal use, Fulcrum Acoustic speakers can sound amazing, but not if you don't apply the recommended DSP. Did you have that?
https://www.fulcrum-acoustic.com/support/processor-configurations/
I've never tried running them without the DSP but from my understanding based on how they're designed to use the DSP, they sound awful without it.

Also you mentioned the room is 80' deep. Sounds relies on physics and since you mentioned the front 3rd sounding decent, I'd imagine that's about the maximum usable throw of this particular cabinet and you'd be looking at adding delay speakers to cover the additional depth.
Funny you should mention this. I told the story about the first time I dealt with this sound system, I undid the DSP settings and opened up the sound. The amp is a QSC CDX 4.2, which is a good amp, but the install tech didn't understand anything about it. There was a generic configuration set which didn't do anything for the system except handicap it. The amp has basic DSP, but to be honest I couldn't tell you the first thing about integrating the speakers. I need to take some classes or read a lot more before I even try. Tuning the old room, though, I'd say I was satisfied with the speakers. New room, I'd have to hear. I've tried to fool around with the Amplifier Manager that QSC lets you have and is through the USB, but I don't think Fulcrum supports that.

The new room will be not only about twice as deep, it's about twice as high. The speakers just weren't meant for the throw we're going to need.

Any suggestions on where to start with DSP learning?
 

DrewE

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Mar 18, 2019
Location
Vermont
You might want to investigate the JBL CBT70J + CBT70JE combination (or something similar). I've done some work in a vaguely similar venue with one (fairly live, roughly comparable dimensions and shape) where it works out pretty well indeed, at least for their needs.

Potential advantages: Decent pattern control, fairly even coverage, articulate and understandable speech reproduction (thanks partly to the pattern control), decent looks, good mounting or flying options available. Potential disadvantages: limited to no very low bass response, not stereo--though getting usable stereo imaging with any system for more than a pretty narrow strip of the room would be highly impractical at best.

I of course still strongly recommend getting some professional consulting if at all possible, at least once there's some chance of the design not changing radically (and preferably while it still could change as needed for acoustics).
 

macsound

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Location
San Francisco, CA
If its specific to the Fulcrum stuff, I'd start with contacting them. They are very willing to work with you on settings to make their loudspeakers sing.
This link (PDF) shows the general overview of what their "presets" do and what they're trying to accomplish with them, which is beyond what you'd be able to tune by ear, things like compensating for delay within the coax driver. Personally, I wish they'd either just make a box that does this or sell powered speakers. But I love how they sound so that's why I complain.

If you just want to learn what DSP does in general, this youtube video about the DBX driverack is short and explains enough to get the gist. Essentially it's EQ, crossover, delay and limiting for your outputs. The reason we do it this way is so it's disconnected from the console and stays the same as long as the PA and room don't change.
 

ACTSTech

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Joined
Nov 13, 2019
Location
USA
If its specific to the Fulcrum stuff, I'd start with contacting them. They are very willing to work with you on settings to make their loudspeakers sing.
This link (PDF) shows the general overview of what their "presets" do and what they're trying to accomplish with them, which is beyond what you'd be able to tune by ear, things like compensating for delay within the coax driver. Personally, I wish they'd either just make a box that does this or sell powered speakers. But I love how they sound so that's why I complain.

If you just want to learn what DSP does in general, this youtube video about the DBX driverack is short and explains enough to get the gist. Essentially it's EQ, crossover, delay and limiting for your outputs. The reason we do it this way is so it's disconnected from the console and stays the same as long as the PA and room don't change.
I understand the DSP, it's that I don't understand enough about how to tinker with it to make me dangerous (though I'm dangerous enough as is...) and improve the sound. The QSC amp we have now has basic DSP, but all I can do is connect to it via the Amplifier Navigator, I don't know where to go after that, and honestly, I don't have time right now. The gentleman who likes to help and is willing to help swears by the installer and won't deviate from the pre-sets, so he's not interested in changing things unless the installer (who did it incorrectly) gives us his blessing. I'll spend a lot of time on the QSC site in the near future.
 

TimMc

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Feb 15, 2017
I understand the DSP, it's that I don't understand enough about how to tinker with it to make me dangerous (though I'm dangerous enough as is...) and improve the sound. The QSC amp we have now has basic DSP, but all I can do is connect to it via the Amplifier Navigator, I don't know where to go after that, and honestly, I don't have time right now. The gentleman who likes to help and is willing to help swears by the installer and won't deviate from the pre-sets, so he's not interested in changing things unless the installer (who did it incorrectly) gives us his blessing. I'll spend a lot of time on the QSC site in the near future.
If you're needing DSP for Fulcum Acoustics loudspeakers you should be in contact with Fulcrum, who can advise on DSP choice and the factory-developed and approved settings for the DSP units they recommend. You will not get optimum loudspeaker performance from other DSPs or using other settings.

What you "do" with a DSP is essentially "cook book" after you know what needs to be changed and why. Some DSP units are not capable of every function required by the loudspeaker and is why Fulcrum offers "good/better/best" advice on DSP units and settings. I've not used or programmed those particular QSC amps and have no idea if they're suitable for Fulcum or not.

Edit ps: What you seek is not so much knowledge of DSPs but how to USE them. If you're "rolling your own" crossovers and filters and limiters for bi/tri-amped loudspeakers, you're attempting to replicate the work done by the loudspeaker manufacturer. I claim little expertise in this type of engineering and have great respect for those that turn out the truly stunning contemporary loudspeakers we enjoy today, with much of the majik, secret sauce, and cosmic confluences built into both the physical loudspeaker structure and sophisticated processing applied via DSP - the latter either in stand-alone units or built into power amplifiers (which may or may not be built into/onto the loudspeaker).

Once we have a "proper loudspeaker" we then deal with the loudspeaker system design for coverage area (all the places people will watch a performance or presentation) and both SPL and tonal evenness of that coverage. Loudspeaker placement and the relative acoustic reflective-ness of surfaces adjacent or near the loudspeakers have considerable influence over intelligibility and coverage - what 'covers' may have poor intelligibility, so an SPL prediction of coverage over an area, by itself, does not guaranty "equal audible performance" across the coverage area. Because placement is something we have either 'lots or not' control over, the most significant variables are the archtecture: dimensions (please no 1:2:3 dimension ratios ), how much of those dimensions are parallel surfaces, and the furnishings and appointments of the space. Usually the audio is the consideration made after all of those choices have been made (see previous "not" 😖 ).

So where's the lesson is this long post script? That DSP is a really, really cool tool that lets us do lots of things that involve amplitude and time, in its various forms. While there are incredibly sophisticated ATMOS®, "immersive" and "object based" loudspeaker deployments and mixing techniques to use them, the kind you or I are most likely to use do not do those things, we can't "create" an enviroment on our budgets. Problems created with concrete, drywall, steel and wood are generally not "equalized" away with electronic devices. The D-9 'equalizer' is the only known solution:
caterpillar-d9-09.gif

The DSP we can afford, either built into amplifiers or as stand-alone processing, can do remarkable work for loudspeaker designers. Most of us aren't qualified to second-guess them. Use what the Loudspeaker Daddy/Mamma/Kin say to use or it ain't their baby, Rosemary... System DSP, usually a stand-alone device at our level, lets us voice the loudspeaker system(s) with EQ, allows us to "align" subwoofers and front fills with the main PA, apply delay and EQ for under-balcony or other zones of coverage the main PA cannot adequately cover. There's a whole art and science to that but it's more do-able by we mere - but trained - mortals.

How deep a dive do you want to take? I suggest some books, the paper things, like Master Handbook of Acoustics by Everest & Pohlmann, 6th ed. About $30 at the usual suspects. Information and science dense but with lots of practical illustrations to help visualize. I owned the 3rd edition and lost it in a move, glad I updated. Sound System Engineering, Davis & Patronis, 3rd ed. and Sound Systems: Design and Optimization, McCarthy, 3rd ed. are also deep water. The earlier editions of Sound System Engineering were how I learned system design fundamentals in the dark days before DSP. The McCarty book is very approachable and Bob is a very good explainer. Do you need to know all this? Eh, you needn't be an expert, you need to know when you're in over your head whilst trying to utilize whatever resources are available to you.

BTW, your audible demonstration to the stakeholders was seriously commendable. :dance: Rock on!
 
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