Design Strand C21 Dimmer Pack in the BOOTH!

[BRichSound]

Hello control booth! this will be my first post! at our High school, we have a strand c21 dimmer pack installed in are booth. are problem here is the sound coming from the fans in the dimmer pack. if the sliding windows on the booth are even slightly open, you can hear the dimmers from the stage. this is a huge problem considering when we are in the booth it makes it impossible to mix anything sound related, or talk to the tech next to me (we use head sets in the both). is there anything we can do to turn the fans down on the dimmer rack? we only have 48 dimmers installed. i have set the minimum fan speed to 2% but that didn't help when it came to bringing up channels, is there a way to set max fan speed? is it possible to build a sound proof wall around the dimmer? thanks in advance for the help!

 

[josh88]

First make sure they are clean. They won't be quite as loud when they are all cleaned out. But you need them going that fast to adequately cool the dimmers. I worked in a similar space with the fans roaring in the background and there's unfortunately not a lot you can do. You don't want to build a wall around them or they won't be able to get the airflow they need and you don't want to try to turn down the fan speed or again, not enough air will circulate through them. Racks just tend to make a lot of fan noise.

 

[FMEng]

Provided that you have enough room, you could wall off the dimmer. The dimmer room would have to be large enough to allow for work clearance around the rack as specified in the electrical code, and adequate air conditioning would have to be installed to handle the full BTU heat output of the dimmer rack. Not impossible to do, but it has to be designed properly and won't be inexpensive.

 

[macwhiz]

Since these fans exhaust, what if you attached the top to a vent plate, like on rolling air conditioners, and had inline fans outside of the booth pulling the air through ducts instead of the built in fans.

 

[STEVETERRY]

Since these fans exhaust, what if you attached the top to a vent plate, like on rolling air conditioners, and had inline fans outside of the booth pulling the air through ducts instead of the built in fans.

Be careful here. A move like this could invalidate the UL Listing (or ETL Listing if it is a later rack) of the rack and cause thermal problems.

ST

 

[avkid]

Now, if you didn't disable the internal fans and just added some external ones.....

 

[phenry]

Unfortunately dimmer rack fans make noise, which is why we recommend installing them in locations where that noise will not be objectionable, but as we are past that point, let’s do what we can.
Do you have a bottom fan rack or a newer top fan rack? You can change your 2% setting down to 0. If you set it for anything other than zero, your fans will never shut off (although at 2%, they won’t be spinning much anyway). You can build a room around your rack. The only clearance we require for warranty front clearance for airflow as cool air comes in from the bottom front and out the top front. If you do that, it will require some special HVAC considerations.
The fan speeds are coded per module type and usage. For scr dimmer modules, when you get DMX above 20%, the fans turn on and ramp to full with more DMX percentage. There are also other provisions for the number of modules on and if any are sinewave or IGBT.
If it does not seem like the fans ever slow down and are either on or off, there is a variable fan speed dip switch that may be turned off. If you think this may be the case, let me know and we can talk further

 

[BRichSound]

I guess we are SOL. are booth is small. It is 12 by 12 feet. with a mackie 32 channel mixer, ETC Element and playback/recording computer on the desk( ie no room) and to boot a c21 dimmer right behind us, so there is no room to build a room around the dimmer. i just wish we could install quieter fans. is this possible?

Also the fans are mounted at the bottom of the rack blowing air up into the dimmers.

 

[josh88]

how much clearance is there from the bottom to the floor? and I feel your pain, that sounds pretty similar to one of our booths in college, and it was hot so we had our own fans on too. The best option for you would be to move the sound into the house somewhere if you've got the space. I'm 99% sure you can't install quieter fans, you certainly couldn't just change them on your own, and I doubt they made a "quiet fan" version.

 

[phenry]

Unfortunately at this point, I will have to refer you to your local dealer. Our current racks use an upper fan kit and we are releasing a baffle kit that mounts to it for situations such as yours. It would require a dealer or service center in your area sell and retrofit it.

 

[gafftaper]

First of all make sure you follow up with Phenry and stay in touch with him. He works at Strand and is your best connection to getting some sort of help for you situation. However, don't get your hopes up. Someone installed the dimmer rack in a terrible place and there isn't that much you can do about it. But what can be done, he will help you with.

I would look at redesigning the back row of your theater in order to create a way to quickly move your sound and lighting gear out of the booth and into the house for a show. It can me done. The high school I used to teach at had all kinds of issues with the booth in the thousand seat theater. We built a rack that made it really easy to move the mixer out of the booth, so the sound op could actually hear.

 

[AudJ]

Unfortunately at this point, I will have to refer you to your local dealer. Our current racks use an upper fan kit and we are releasing a baffle kit that mounts to it for situations such as yours. It would require a dealer or service center in your area sell and retrofit it.

My C21 is installled on the STAGE! Yes, I strongly advised against this, but the $ to move to the room designed for a dimmer rack was more than our school could handle. They are sorry now, as it is nearly impossible to rehearse and perform in the semi-professional orchestra housed on our stage, in addition to the obvious impact on the 14 student performances each year. Please keep us updated on the baffle kit.

 

[phenry]

Thanks for checking back in on this.
The baffle kit has been released. Any dealer should now be able to get it for you. Our part number for it is 75520. Here is a link.pdf to the data sheet.

 

[AudJ]

Thanks for checking back in on this.
The baffle kit has been released. Any dealer should now be able to get it for you. Our part number for it is 75520. Here is a link.pdf to the data sheet.

Thank you for the info! Unfortunately, it seems this baffle only applies to top fan C21 units. I have a bottom fan unit installed in 2010. I like the foam insert idea - can a duct be run from the top of this, with a secondary fan down the line somewhere? I was wondering if we can run another fan drawing air through, in the hope the bottom fans would turn on less frequently?

 

[Aman121]

I definitly feel your pain, we have an i-96 rack installed right on stage, where the old dimming system was. The school cheaped out and kept the same 50 year old lights and wiring and just replaced the dimmers.

 

[phenry]

Thank you for the info! Unfortunately, it seems this baffle only applies to top fan C21 units. I have a bottom fan unit installed in 2010. I like the foam insert idea - can a duct be run from the top of this, with a secondary fan down the line somewhere? I was wondering if we can run another fan drawing air through, in the hope the bottom fans would turn on less frequently?

I can't recommend any ducting or external fans. You will run into issues with compliance ratings, risk of overheating if it is under done, and ease of access to the dimmers and breakers.
In your case, the only thing that could be done is to have the bottom fans removed and put the top fan kit and baffle in. The fan housings are just assemblies that don’t require any modification to the rack other than running a new fan power harness to the top.

 

[AudJ]

I can't recommend any ducting or external fans. You will run into issues with compliance ratings, risk of overheating if it is under done, and ease of access to the dimmers and breakers.
In your case, the only thing that could be done is to have the bottom fans removed and put the top fan kit and baffle in. The fan housings are just assemblies that don’t require any modification to the rack other than running a new fan power harness to the top.

Best idea I've heard yet! Thank you!

 

[Les]

I definitly feel your pain, we have an i-96 rack installed right on stage, where the old dimming system was. The school cheaped out and kept the same 50 year old lights and wiring and just replaced the dimmers.

That's actually not a bad way to do an upgrade if you don't have the capitol to do it all at once. Think about it this way: you can replace lights one at a time as needed. If an aging dimmer rack goes down: boom, there goes everything.

Hopefully they at least checked the wiring for safety. I can't imagine a factory trained tech tying a new dimmer in to unsafe wiring.