ANS Gymn Project

[malsackj]

A few years ago La Plata Maryland was devasted by a twister (about F4)

I have started to work on a project to improve the sound system in the local Catholic School Gymn.

I purchased an EV Force tweeter for a school gymn project.
25 dollars what deal . They are using 12, 8 inch 70v speakers. I plan to add a good sub and the tweeter to improve the sound some. They have added some corner absorbers to start room acoustics correction but it will be a small help. Tweeter will be working the 2k to 20k with a 60 watt toa amp another 20 dollar deal. That should help clear up the midrange and give it some reach. RTA had the inverted v pattern. bottom was around 200 and top was around 3k, reverb was forever. Mostly from those 12 speakers in various locations firing at same time. Mounted in roof down on floor.

Plan to seperate those twelve into rows of 4 and see if digital delay and time align will help reduce reverb and improve clarity.

We tested one PTA session using the little Ev and managed to get the gymn to 80 db across the width of BB court. 6.5 and tweeter. JBL 2600 cabnet 220 watt amp. Reverb was not bad and people were able to hear.

Currently in the works is the move of two Yamah 12 in 2 way speakers to wall mounts at a stage to fill the seating area on the floor of the gymn. Plan to use the EV force tweeter monted in new cabnet center stage front line firing down into seating. This will help to give the stage as the front of the sound source. Then a plan to add some good sub will be reviewed to bring the 50 hz to 200 hz.

Stage is center of length and seating is width deap with a set of bleachers on rear wall only.

 

[PaulyT]

Wow, that's an interesting project. Talk about a big space and a challenging room!

 

[malsackj]

I have found the documents from the source speaker and crossover on the Evoice tweeter.

So the question here is for Soundhound and possibly anyone else.

The protection S1P in the parts list is Polyswitch Raychem RXE 075.

If we rebuild this crossover is the Parts Express 071-258 RXE075 the same part?
I am believing this to be true and just looking to confirm.

 

[malsackj]

Here is a few pictures of the tweeter purchased on Ebay for 45 dollars.
Confirmed working. The Horn output is 60 deg horizantal by 40 degree vertical.

 

[malsackj]

I used Room EQ wizard to do a frequency sweep and establish the base line.

here are some views on the sweep and the waterfall plot showing the large amounts of reverb in the room.

 

[malsackj]

Delivered the Toa D-1103 digital delay device to the Gym. one input to three outputs.
Now to find the amplifiers. Speaker mounts will be installed hopefully later this month and the tweeter box is being constructed to be installed in Feb.

 

[malsackj]

Wall mounts are up on the sides of the stage with a 20 degree tilt down and a safety eyebolt for attaching the speaker to the wall is in place. Wires and speaker hopefully in the next two weeks.

Wireless AT vhf mike and diversity receiver has arrived to have the remote antenna installed for getting from the performance area to the system closet. This is replacing a radio shack wireless unit.

 

[malsackj]

Crossover is built for the tweeter, Yamaha speakers are up on the brackets at the stage.
Will set up wireless mic to current system this weekend with the 60 watt amp to feed the tweeter. Will be setting up 120 watt amp to feed the two Yamaha speakers. Then another run on the RTA software to start setting the tweeter up, and correcting the room EQ settings. If time permits I will be starting on the digital delay to the first set of time delay.

 

[malsackj]

Corrected the EQ and applied some compression today. Found the EQ was boosted to max on 22 to 40 hz. In a gymn this is not good with the speakers they are running. Cut the 20 to 60 Hz because the speakers cannot support from 100 hz and below. This project will need a good Sub.

Also found the Peak in the 7k range and tamed that back. The open microphones were not in feed back any more because the compressor flattens out the peaks and will not allow the microphones to get up into a feedback point. Now I plan to get back into the room and RTA and equalize and adjust up to feedback and reduce these problem frequencies to allow a greater gain before feedback.

 

[malsackj]

The High frequency driver is now in a box, crossover is mounted on sidewall.
the transformer on the bottom is 30 watt 70V constant voltage system.

eye bolts are ready for mounting to ceiling in gym. I hope they get the gear together and get up there and mounted soon to make the system friendlier to music programs.

For testing I used my home stereo and plugged into the quarter inch inputs on the box. It sounds good at 50 watts power. 3k to 18K output.

 

[malsackj]

I have another AT wireless body pack and receiver to add to the system.
They had a small problem with the mixer that will not power up so there budget is being taken up with getting the front of the system replaced.

 

[PaulyT]

That's cool, J. I'd love to see some pics of the gym sometime just to get a better feel for the space you're working with. Cool that you get to do a lot of DIY work in there.

If you need an inexpensive quality 16 channel analog mixer, you know where to go.

 

[malsackj]

Yes keeping that in mind

There budget is very restrictive. That was why most of this is Ebay sales and volunteers. Looking to give Flint some credit for his Sound baffles and acoustics inputs on this site. They have not taken any of these projects on to help reduce the reverb yet.

When looking at the charts you can see the long delays and comb filtering going on in a gym basketball court. I think the power of this 60 watt driver in the 3 k to 18 k range will help to improve the childrens voices and womens voices inteligibility because of the powerfull single source. I hope to soak up some of the other midrange with the acoustic pannels on the rear wall.

 

[malsackj]

Ok Pauly here is the pictures.

Over the weekend the RCF/EAW/Mackie DX-8 mixer failed and they had to order a replacement. I just returned from unracking and racking the replacment.

We have basic setup completed on the replaced device.

I took the high frequency driver in the cabnet and placed on stage. We powered it up and using a mic I did a simple couple of sentences.

As expected we had high frequency slap back, from the driver running with 30 watts. I hope now to convince them to get the volunteers and donations together to make some sound panels for the rear wall with the bleachers.

On top of the closet on the right back corner we are discussing putting in a base trap with 703 with about a 5 foot cross section. This area has one remaining speaker where there was two. The other speaker was a Yamaha 12 inch 2 way that was mounted over the stage.

 

[malsackj]

The gym floor is the original basketball floor for the Washington Bullets. It was donated by the owners when the old arena was replaced.

On the stage is the box with the High Frequency driver ready to be mounted up on the ceiling near the curtain that devides the gym. On each side of the stage you can now see the two Yamaha speakers. The sound is good out to center court but the highs dont cary out past the center line. This is where the new driver will help the other half and most of the bleachers.

 

[malsackj]

Those other speakers in the back I believe to have some pizo tweeters and they dont have the power handling of the yamaha's. They put the four speakers, two on each side of the bleachers because people complained that they could not hear or understand the people speaking. Mostly the problem is the comb filtering from the 12 speakers located in the ceiling. As we move their system into two systems one for basket ball and buzzer noise and one for spoken word and music with room corrections. I hope to start seeing a difference. I think that when the EV driver is in place and powered the rest of the music and spoken word will be much improved.

 

[PaulyT]

Thanks! Wow, yes that's a challenging, highly echoing room. And on a shoestring budget. That's cool that you're able to help them!