Live sound system w/ $7K?

[ocinn]

And, as noted elsewhere, a pair of subs or 2 is better than just one.

A pair of subs positioned farther apart than 1/4 wavelength of the crossover frequency will perform worse than a single subwoofer in the real world. The 3db benefit of 2 subs goes out of the window when there is massive lobing cancellation off center.

The only way you can make >1/4 wavelength subwoofer spacing work is if you have simulation software and individual delay and level control down to the 0.1ms range, and even then it’s a trade off on output. I don’t think OP has DSP solutions nor the time or planning resources to do it correctly.

But yes, You are correct. A “small” mid/hi on a pole, solely responsible for producing their designated (hi-pass) frequencies from a high location for optimal crowd coverage, and a subwoofer(s), which are boundary loaded by the floor, playing cleanly and efficiently is far superior to trying to deploy full range speakers on poles. They will run out of amplification, introduce huge IMD on the woofers while attempting to play low bass notes and they do not get boundary loaded like floor stacked subs.

Not to mention having to lift 100lb boxes 6+ ft into the air.

 

[Rja4000]

I don’t think OP has DSP solutions

I proposed Nexo with dedicated amp, which, of course, includes DSP.

 

[kipman725]

https://jblpro.com/en/site_elements/jbl-professional-sound-system-design-manual-1999-edition-pt-1-1

worth a read for the basics of positioning speakers

 

[sarumbear]

A pair of subs positioned farther apart than 1/4 wavelength of the crossover frequency will perform worse than a single subwoofer in the real world. The 3db benefit of 2 subs goes out of the window when there is massive lobing cancellation off center.

Are you taking into account the standing waves that will occur in a small to mid-size venue?

 

[neRok]

I promise you won't be disappointed by 2x DZR10, 2x Crank stands, and a DXS sub.

I've just read through this thread after it was linked in the recent Crown amp front page review. I've been interested in the likes of JBL SRX835 since amirm reviewed it, and OP's Yamaha DZR315 is of course similar. But after reading posts in this thread I'm inclined to agree that if you can have subwoofer(s) then there's little to gain by having "full range" 3-way PA speakers.

But I wonder about the size of the woofer in a 2 way then. If you have subs covering the bottom end, and your SPL requirements are merely modest, and you don't have weight/size concerns like OP, then would you be inclined to go for a speaker with 8/10/12/15 inch woofer?

Looking up some spec sheets I've noticed that the bigger woofers generally have a bit more low bass, which doesn't seem necessary if there are subs. Often the bigger models also play a little louder, which isn't necessary in my hypothetical. 1 major difference is that the bigger woofers generally cross over at lower frequency to the HF, which could make a difference? (although in DZR range it isn't very different, but in CDD-Line it is a fair bit). And sometimes the HF compression driver increases in size with the larger woofer (like in CDD-Line), but perhaps this is just to match the higher total SPL requirements and/or the lower XO frequency?

So any comments about that? I'm interested to get some for playing heavy metal music, so I want to ensure I get enough "slam", and thus I wonder how much impact the woofer size has for this high SPL pro gear when not being used near its limits? Also I'm considering "dipping my toes in the water" with a cheap Aussie brand I've noticed - AVE Revo DSP Speakers. Probably the quality isn't there compared to DZR and stuff, but are there any red flags that stand out to you with such a speaker?

Just to illustrate, here is outdoors bass distribution averaged over 32-63Hz in a setup with just the two outside subs enabled:

And now enable the two center subs that are a meter forward, in front of the stage, no delays, no gain differences:

Something to keep in mind if you do bigger gigs at some point; being able to expand the system with more subs is a good thing.

This sort of stuff is quite interesting. In the last week or so I happened to watch videos by Dave Rat on the subject such as Bassnectar 360 Subwoofer Sound Design. In it he runs through a few different ways of configuring front and rear subs. The 3rd and 4th examples I've screenshot below show how much more bass is projected forward, instead of back;

I wonder if this could be used for indoor PA to reduce bass reflections off the back wall? In effect trying to form the "plane wave" like is done with Single/Double Bass Array? Perhaps to take it a step further, 1 or both of the rows of subs could also output a very delayed signal to negate the returning wave like Virtual Bass Array tries to do?

This is interesting to ponder, but alas that is all I can do. Also youtube has just recommended a video from a different channel, Two Subs, Six Setups | Killer Low End For Portable DJ's and Small Concerts, so I'm going to check that out...

 

[Rja4000]

There are cardioid or directional subwoofers on the PA market.

https://www.fullcompass.com/common/files/13606-CD18DataSheet.pdf

You need 2 amp channels per sub, of course.

 

[neRok]

Also youtube has just recommended a video from a different channel, Two Subs, Six Setups | Killer Low End For Portable DJ's and Small Concerts, so I'm going to check that out...

So he did another method in that vid he called "inverted gradient stack" which is stacked subwoofers in the middle, 1 firing forward and 1 back, like shown in these screenshots;

He said it only rejects in a narrow frequency band compared to cardioid alignment, but if trying to do VBA/plane wave stuff then perhaps you only need to negate the frequency associated with the rooms length?

Edit: I'm going to move this sub discussion to a better thread... see here.

 

[ocinn]

I wonder if this could be used for indoor PA to reduce bass reflections off the back wall?

I deploy cardioid/endfire/exotic subwoofer arrays all the time indoors, however I do it to reduce the bass level on stage/DJ booth and for dispersion control over the dancefloor, and not to counteract room effects.

Room effects are rarely even thought about in touring/temporary install live sound because they are unreliable, variable, and require hours of measurements and trial and error to optimize, which no one has outside of permanent install work.

But after reading posts in this thread I'm inclined to agree that if you can have subwoofer(s) then there's little to gain by having "full range" 3-way PA speakers.

The benefit of 3-way consumer PA speakers is less to do with low frequency extension and more to do with placing critical frequency ranges on their own driver (and constant directivity horn), which allows for smoother and more consistent dispersion over the audience as well as lower distortion/higher SPL.

In OPs specific gripes with his current rig, the clear solution is a powerful subwoofer and 10” mid-his placed at the right height and angle, however a DZR315 + sub would project a smoother frequency level gradient over the audience due to the fact it is a 3-way, but doesn’t solve any issues for OP.

But I wonder about the size of the woofer in a 2 way then. If you have subs covering the bottom end, and your SPL requirements are merely modest, and you don't have weight/size concerns like OP, then would you be inclined to go for a speaker with 8/10/12/15 inch woofer?

90-150hz is still somewhat (in excursion/power) low frequency for a PA woofer to play. The trade off with going small mid-hi + sub vs large full range is that you lose headroom around the crossover area. This is never a real world issue as people that need the huge output at those frequencies are not the same people that are forced to make drastic compromises to save weight, space and effort.

Lots of techno sound systems run dedicated “kick boxes” (60-90 hi pass, 160-260 low pass) boxes to boost headroom around the tactile chest thump area.

1 major difference is that the bigger woofers generally cross over at lower frequency to the HF, which could make a difference? (although in DZR range it isn't very different, but in CDD-Line it is a fair bit). And sometimes the HF compression driver increases in size with the larger woofer (like in CDD-Line), but perhaps this is just to match the higher total SPL requirements and/or the lower XO frequency?

Bigger woofers beam earlier so crossover needs to be lowered to keep directivity in check. As you lower the crossover you need to run larger compression drivers. This is normal.

 

[ChrisG]

In OPs specific gripes with his current rig, the clear solution is a powerful subwoofer and 10” mid-his placed at the right height and angle, however a DZR315 + sub would project a smoother frequency level gradient over the audience due to the fact it is a 3-way, but doesn’t solve any issues for OP.

What's a frequency level gradient, and why would a 3-way automatically be better than a 2-way speaker in this regard?


I've been doing live sound, including designing speakers for that purpose, for around a decade and haven't come across this term.

Thanks,
Chris

 

[peniku8]

This sort of stuff is quite interesting. In the last week or so I happened to watch videos by Dave Rat on the subject such as Bassnectar 360 Subwoofer Sound Design. In it he runs through a few different ways of configuring front and rear subs. The 3rd and 4th examples I've screenshot below show how much more bass is projected forward, instead of back;
View attachment 300532
I wonder if this could be used for indoor PA to reduce bass reflections off the back wall? In effect trying to form the "plane wave" like is done with Single/Double Bass Array? Perhaps to take it a step further, 1 or both of the rows of subs could also output a very delayed signal to negate the returning wave like Virtual Bass Array tries to do?

I've mixed a show in a venue called Haus Auensee (holds ~3500 people) and the system engineer set up the subs in cardioid because the stage is a massive concrete slab, which would've resulted in a pretty bad quarter wave cancellation and thus a massive notch somewhere around 50Hz or so. The cardioid setup reduced that rear wave and thus the reflected sound and the subsequent cancellation. With the added benefit of cleaning up the on-stage sound of course.

What's a frequency level gradient, and why would a 3-way automatically be better than a 2-way speaker in this regard?


I've been doing live sound, including designing speakers for that purpose, for around a decade and haven't come across this term.

Thanks,
Chris

I think he is talking about off-axis response. A 3-way isn't automatically better than a 2-way, but it's easier to design a 3 way with consistent off-axis.

There are cardioid or directional subwoofers on the PA market.

https://www.fullcompass.com/common/files/13606-CD18DataSheet.pdf

You need 2 amp channels per sub, of course.

I'm not a fan of built-in cardioid. You lose all the flexibility you could have with arrays (in terms of setup and sound quality) and gain... probably a bit less used truck space (only in scenarios where this setup would be ideal).

 

[ocinn]

What's a frequency level gradient, and why would a 3-way automatically be better than a 2-way speaker in this regard?


I've been doing live sound, including designing speakers for that purpose, for around a decade and haven't come across this term.

Thanks,
Chris

Probably not the right wording, I was half asleep when I wrote that.

Same as the vertical dispersion plot we talk about here, except in correctly deployed live sound applications it manifests as changes in tonality from the front of the audience (low vs speaker), to the back of the audience (on, or slightly above axis). In the same way that generally, 3-way speakers have wider/smoother vertical dispersion vs their 2-way counterparts, a 3-way speaker (assuming the same dispersion spec of the horns, will be more tonally balanced across the dancefloor, compared to a 2-way).

However high-end pole-mount speakers are usually designed to be somewhat concentric (Meyer X40, D&B V10P/Y10P, Martin CDD-Live, L'Acoustics X15, all Danleys, PM60/90, B&C 215-DCX, etc...) so less of a concern, even for 2 ways.

I'm not a fan of built-in cardioid. You lose all the flexibility you could have with arrays (in terms of setup and sound quality) and gain... probably a bit less used truck space (only in scenarios where this setup would be ideal).

D&B really knocked it out of the park with cardioid line array boxes, and then just ruined it by transitioning all of their touring subs to cardioid. All the rental houses I work with are hoarding their B22 stock for dear life.

 

[dannut]

1 major difference is that the bigger woofers generally cross over at lower frequency to the HF, which could make a difference? (although in DZR range it isn't very different, but in CDD-Line it is a fair bit). And sometimes the HF compression driver increases in size with the larger woofer (like in CDD-Line), but perhaps this is just to match the higher total SPL requirements and/or the lower XO frequency?

A larger source has 'pattern control' to a lower frequency. Arguably it is beneficial.
OTOH the pattern gets too narrow if a large circular source is crossed too high. In a regular 15" 2way PA box rarely you see a horn crossed <1000Hz to correctly mate with a 15". The result is a response hole at the edges of the pattern in the 1200-1600Hz region. Compromises.

About them CDDs - in addition to being a coaxial (no vertical lobing) and having correctly pattern-matched low-higs, they also have asymmetrical coverage. Wider coverage below and narrower above the speaker centerline. Can lessen the need to have center-fills on some venues. No wonder people like them.