I'm working on a portable, cart-based PA system for outdoor events.
Covering crowds of thousands is a huge challenge, and it is crucial to get speakers high into the air so the acoustic energy is not absorbed by the crowd. I have found line of sight between audience members and the PA is critical for intelligibility. I am mostly concerned with speeches, so bass response is not important.
In the pro audio world, they use line array towers hoisted high into the air to cover large events, with similar "delay towers" deeper into the audience to reinforce the sound with appropriate delay.
I am hoping to emulate this somewhat with a low cost, lower quality system that can be easily set up and taken down.
I am happy with my current version, but excited to make a few improvements to the horn design and the DSP programming.
The system uses a two-way speaker design where the mid/high horn is mounted as much as 5 meters(15'ft) above the woofer. I am using very strong telescoping carbon fiber cleaning poles as the masts.
Here’s the current signal chain and driver setup:
In my tests it sounds good as long as one is standing in the coverage zone of both the woofer and the horns. It is very intelligible, though far from "full" sounding as the lows are pretty underpowered.
By using two of the horns I can point to 180° for large crowds. I have access to a printer with 350*320*325 mm³ Print Volume, so ideally it fits in this space.
Making the horns sound better and weigh less would help even more, and let me raise them higher safely. The horns are connected with all-metal hardware and each has backup safety tethers to reduce head injury risk.
I’m currently using an injection-molded Goldwood GM-450PB (90° x 40°), but it’s far more rugged than I need. They also rely on an adapter which I imagine harms the sound somewhat.
To keep things manageable, I’m trying to make the horns as light as physically possible, I'd love to print them in PETG.
The horn geometry stuff is frankly terrifyingly complex to me, and I wonder if I could get help creating a single-surface STEP file of a horn with similar or better frequency performance, which I can thicken in Fusion to to be printed in one piece.
Also would love to hear thoughts on the project!
Thanks!
Covering crowds of thousands is a huge challenge, and it is crucial to get speakers high into the air so the acoustic energy is not absorbed by the crowd. I have found line of sight between audience members and the PA is critical for intelligibility. I am mostly concerned with speeches, so bass response is not important.
In the pro audio world, they use line array towers hoisted high into the air to cover large events, with similar "delay towers" deeper into the audience to reinforce the sound with appropriate delay.
I am hoping to emulate this somewhat with a low cost, lower quality system that can be easily set up and taken down.
I am happy with my current version, but excited to make a few improvements to the horn design and the DSP programming.
The system uses a two-way speaker design where the mid/high horn is mounted as much as 5 meters(15'ft) above the woofer. I am using very strong telescoping carbon fiber cleaning poles as the masts.
Here’s the current signal chain and driver setup:
- 2x JBL Selenium D250-X GW 1" phenolic compression driver (1-3/8"-18 TPI)
- 2x PRV Audio ADM25-50 adapter (to 4-bolt 2″ horn mount)
- 2x Goldwood GM-450PB horn
- 12" woofer (Behringer b112d, removed old(broken) amp, not using tweeter) near ground level to fill in 50hz-400hz
- DSP via Dayton Audio KABD-4100, handling crossover, delay, and EQ (using REW for auto eq)
In my tests it sounds good as long as one is standing in the coverage zone of both the woofer and the horns. It is very intelligible, though far from "full" sounding as the lows are pretty underpowered.
By using two of the horns I can point to 180° for large crowds. I have access to a printer with 350*320*325 mm³ Print Volume, so ideally it fits in this space.
Making the horns sound better and weigh less would help even more, and let me raise them higher safely. The horns are connected with all-metal hardware and each has backup safety tethers to reduce head injury risk.
I’m currently using an injection-molded Goldwood GM-450PB (90° x 40°), but it’s far more rugged than I need. They also rely on an adapter which I imagine harms the sound somewhat.
To keep things manageable, I’m trying to make the horns as light as physically possible, I'd love to print them in PETG.
The horn geometry stuff is frankly terrifyingly complex to me, and I wonder if I could get help creating a single-surface STEP file of a horn with similar or better frequency performance, which I can thicken in Fusion to to be printed in one piece.
Also would love to hear thoughts on the project!
Thanks!
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Ah ah! You mimic that situation in your little space
I mean...you should overcome the distribution of sound in say- a 20x 20 m area - with enough power and even covering the audience with full spectrum radiating sources that can be subdivided into units with specific drivers for the given function.
I don't see the typical subwoofer (array- coz' it's never enough) and head system, just a too stretched in height dismantled system.
The idea is good - sound from a 45° source above the head.
Experiment can be done with the existing speaker. The problem is how to suspend a mass.
I fear some problems below the Schroeder's frequency (?!) may arise. Some speculation about WHY in the Altec's VOTT the HF horn is near the woofer horn, and what's that woofer horn?!
I fear some problems below the Schroeder's frequency (?!) may arise. Some speculation about WHY in the Altec's VOTT the HF horn is near the woofer horn, and what's that woofer horn?!