Personal monitoring affordably for 20 people

[cedd]

Hi all

I've got a show next year that's going to have a 20 ish strong offstage choir to supplement the on stage chorus. It's looking like they're going to need to be on headphones for their monitoring. One mix to them all will be sufficient, but they'll each need a volume control. 

I've seen drawings in the past for an attenuator/volume control that could be attached in multiples to a regular power amplifier, but I can't find it anywhere now. 

I don't have heaps of time on my hands these days, so if I'm doing something homebrew I'll need to get started pretty quick and it'd have to be something very simple and speedy to build. 

One concern with this many units is that cabling will start to become reasonably significant. Even running it down XLR that's 20 xlrs back to some sort of splitter. 

Another option would be to buy 4 x 8 channel headphones amps and then run trs out to the headphones, then use inexpensive regular headphones volume controls for each user as an attenuator. Again, lots of cabling, but less to build beforehand. 

 

Or.... we go wireless with something like a silent disco bundle. Either hired or bought. The down side to this is battery charging, but that's not insurmountable. I could probably buy said system and find hire opportunities for it again in the future. There are also tour guide systems available for similar prices, though I think silent disco might be the most suitable form factor. I could foresee something like this coming in useful in the future for audio description as well. I can afford to lose one UHF channel to run it on. 

Does anybody have any thoughts or suggestions? I've got until march to get this sorted so hopefully plenty of time to think about it, just not much spare time to build stuff these days! I often like putting these things out here just to start a discussion - helps me to gather my thoughts, even in writing the first post. 

[boatman]

Silent Disco sounds like the best way to go. There are tour guide systems based on PMR446 radios which might also work but could be much more susceptible to interference.

Ali Express currently have a 30 headphone Silent Disco setup for only £81.34 (+£50.66 shipping!) here:

https://www.aliexpress.com/item/4000613273242.html

There's a sale coming up and the price will drop by £17 on August 18th but the shipping will probably stay the same.

[themadhippy]

20 1 watt amps based around the LM386.Maybe 4 channels per box,signal and 12v in and out on 4 pin xlr.

[cedd]

14 hours ago, boatman said:

Ali Express currently have a 30 headphone Silent Disco setup for only £81.34 (+£50.66 shipping!) here:

https://www.aliexpress.com/item/4000613273242.html

There's a sale coming up and the price will drop by £17 on August 18th but the shipping will probably stay the same.

Sadly that item is a victim of "creative marketing" - the lower cost is for the final option, a wireless microphone system. The silent disco system is £648.39. But yes, that's the one I was looking at, and apart from needing a load of AAA batteries, is pretty much the perfect solution.

[Stuart91]

If you're unlikely to need the system again, then rental might be an option?

One thing I'm not sure about with the silent disco systems is latency. Tens of milliseconds wouldn't be a problem for a disco but could mess up the timing of a choir. 

[Dave m]

Do they really need cans?

surely they can perform as a choir in unison/tune.

Timing wise you can have an MD on cans and a (zero delay) video link.

[Robin D]

Or a carefully mounted monitor in the wing to give them the timing. 

It just seems a lot of work for something I have seen many times especially in kids shows. Just a stage monitor feed into a single box does the trick unless it's a massive stage. In fact we run it into both wings. 

 

[sunray]

Get headphones incorperating a volume control then just distrubute with a stereo amplifier and harnes with lots of sockets.

 

First hit for Headphones with volume control: https://www.aliexpress.com/item/1005001993015951.html?

[themadhippy]

Quote

then just distrubute with a stereo amplifier

the output stage of your average stero amp is going to love driving  20 sets headphones in parallel

[neilalexrose]

Autograph have headphone boxes that run from a standard PA amplifier. So if its for a short run, then maybe consider a hire? 

They have an in and out socket, so it’s one feeder cable to the first unit, and then they all link together.

Esentially its a 100ohm* variable resistor in a box wired from the speaker level input socket (Autograph’s are on XLR, but we’ve made a set that uses NL4 and have the option of 2 channels), to a 1/4” headphone output. On our boxes we’ve added a mini-jack socket in addition to the 1/4” jack with a resistor in series to deal with the low impedence of in-ear phones vs higher impedence headphones.

Ours tend to come out for larger group recording sessions. Since the aquisition of an ME1 personal monitor system for musicians we haven’t deployed them on a show for a while.

Neil

*I’m fairly certain thats the value, but it’s been a while since we constructed ours.  It could also be 1k ohm and I’m actually thinking of the pots in our old show relay speakers. I’ll have to check and see if we still have the schematic on file.

Edited August 18 by neilalexrose

[Dave m]

I have bodged together headphone distribution from speaker outputs into boxes containing 4/6/8 headphone sockets. It was years ago and basically thrown together as a one off. It worked. No user volume so fairly basic
 

But you’d end up with buying a ton of headphones as a one off. 
I did buy a bulk pack of headphones from Amazon once and they were £1.99 a pair

Not these but similar

https://www.amazon.co.uk/Classroom-Headphones-Earbuds-Libraries-Hospitals/dp/B0B151KKVT/ref=sr_1_1_sspa?crid=60BUAHZJ3U0M&dib=eyJ2IjoiMSJ9.HlLgAcuBfJPJ9VqBXJLq2LUhnRZ5LK6BLjAQ9Xb9sRrTpDITIwWS8_STkI9Q3prIbyXwvYUjCS9xWHAabmbzdEyaRkoFYERJ091FDFDW6EIujhUt7VAWS9w72OsCd-5A44S-dI9lulTHwEPbW8ODcFmY57sidOcm_Xs92o42e0Byjx1vAu3ZZIuTXv8aCfMfimyVBV3xusEDdTl3bk44BI3quEF8R0aAmwIi4ki37kYUmeszQZEQPtUM8CtJnhPXa_HXHLfPqYAy1jjvx8VHIxG84zSvRudtXHW5txOkB3w.7XA3e6gXgN_GCJT4YEaSkQp4TwcwCmA0EEsZol1e38U&dib_tag=se&keywords=bulk+wired+headphones&qid=1723987265&sprefix=Headphone+bulk%2Caps%2C92&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

I still don’t see the need though, with the info given..

[sunray]

23 hours ago, themadhippy said:

the output stage of your average stero amp is going to love driving  20 sets headphones in parallel

 

8 hours ago, Dave m said:

I have bodged together headphone distribution from speaker outputs into boxes containing 4/6/8 headphone sockets. It was years ago and basically thrown together as a one off. It worked. No user volume so fairly basic

I too have done this for a recording session, I used a BT jackstrip and wired all 20 in parallel. Bearing in mind it was a 10W or so domestic HiFi I added a series resister probably in the order of 10 ohms to tame the whole set-up.

 

However I do think serious consideration has to be given to this:

9 hours ago, Dave m said:

don’t see the need though, with the info given..

 

[adamburgess]

Any possibility of sending a line to a monitor, an (analogue) video line, with a local mixer with mics for the chorus in a different room?

I've played/MD'd a good few musical theatre gigs with band and extra BVs in a different room. 

A few XLRs and a TV sounds easier than a whole different system. (Providing you can find a room, and the offstage chorus aren't needed on stage 3 seconds after the number has finished…)

[ninjadingle]

If you really want to go on cans then look at the Art 4 way headphone amp. It has dual outputs (1/4" inch and 3.5mm) so no need to mess around with adapters and the input is paralleled so you could link through using alternating 3.5mm cables and 1/4" cables? Might need more of them compared to the 8 way rack mounted ones but means their headphones should be able to plug straight in rather than use extensions etc that you'd need with the 8 way versions.

[sunray]

12 hours ago, ninjadingle said:

If you really want to go on cans then look at the Art 4 way headphone amp. It has dual outputs (1/4" inch and 3.5mm) so no need to mess around with adapters and the input is paralleled so you could link through using alternating 3.5mm cables and 1/4" cables? Might need more of them compared to the 8 way rack mounted ones but means their headphones should be able to plug straight in rather than use extensions etc that you'd need with the 8 way versions.

Please note the DC input connector is wired correctly: with the centre pin being 0V/ground and the outer being +12V.  I've not used the brand myself but have been warned about the power connector. I have used the Behringer HA400 - all 1/4" jack -  at just under half the price, to good effect albeit a little noise which is quickly lost in the programme sound, however this https://www.aliexpress.com/item/1005002959173421.html?      appears to be the same product at 10% of the price.

Edited August 21 by sunray