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Assistive Listening Systems

Discussion in 'Sound, Music, and Intercom' started by jonliles, Feb 17, 2017.

  1. jonliles

    jonliles Active Member Fight Leukemia

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    The ALDS at the PAC I work with has died. The packs & receiver are 20+ years old and simply work out. The system takes a feed from the board into the receiver. The space black box space is roughly 60 by 30. Nrmally the audience sits along the long access, occasionally in a thrust configuration. The ALDS mic is an over gained Shure 58 hung in the middle of the acting space from a trim height of roughly 15feet (mic not fed fthrough mains).

    2 Questions:
    1) What ALD System do you use and what do you like / not like about it
    2) What microphone would be better? I was considering 2 or 3 choir drop mics.

    Thoughts?
     
  2. MRW Lights

    MRW Lights Active Member

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    There's a lot of options out there these days... Sound Associates is a favorite here in NYC, I also like Listen Technologies products. The mic you're using might be fine. I typically use a shotgun pointed at the stage, Audio Technica makes some good options as well as RODE. Choir Mics can have a drawback of proximity effect and the need for a higher SPL. The signal to noise ratio may not be favorable depending on your space and system, but it's all a matter of preference really.
     
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  3. sk8rsdad

    sk8rsdad Well-Known Member Premium Member Fight Leukemia

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    We currently have a Listen IR system fed from a Sennheiser ME66 shotgun mic routed through dedicated signal processing. It replaced a Phonic Ear FM system.
     
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  4. Van

    Van CBMod CB Mods Premium Member

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    When building the Morrison Street Theatre at ART in Portland, I purchased and installed a Listen Technologies system. I think they used my thank you letter as a promo for a while. I was bowled over by the degree of customer services and the quality of the gear. I think the worst issues I had with the system was showing people how the ear piece was worn. Ours was Radio not IR.
     
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  5. BillESC

    BillESC Well-Known Member Premium Member

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    Jon,

    I've installed a lot of Oval Windows inductive loop systems with great success. About 85% of people with hearing aids will pick up the sound with no receiver required, those who don't have T coil aids can use a receiver and ear buds.

    I always use an Aux out from the board as opposed to a single mic for the feed.
     
  6. Moose Hatrack

    Moose Hatrack Active Member

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    I have nothing but good things to say Listen support. They tried everything on our LT800. But since 2007 I haven't been able to find a reliable channel in our old location or our new location. We have LR-300-072 receivers. I wish I had been able to get the more expensive receivers with channel indication. On the lighter side, conductive hearing loss in my left ear makes me a candidate for a BAHA (Bone Anchored Hearing Aid). BAHA starts with a titanium post screwed into the old skull. The post is exposed so you can snap a tiny processor\transducer on and off as required. Bone conduction carries sound from the transducer to the nerve. If I go this route my head will have an aux level line-in. It also picks up telecoil and blue tooth. As fun as that sounds, I'm a little worried about losing stereo imagery so I'm getting a second opinion on reconstructive surgery.
     
  7. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    Reading of your BAHA, and in particular your mention of stereo imagery, brings back memories of an installation I was involved with installing 64 channels of QSC amplifiers driven by 64 channels of BSS Blue powering an array of 64 small speakers in a spherical array within a hemi-anechoic acoustic chamber on the campus of Western University in London, Ontario. In a simplistic explanation, the subjects under test were to sit on a tall stool such that the theoretical center of their skulls were centered within the array such that sounds were fired at them from four elevations surrounding them from 16 sides. The company I was with only had to supply and install all of the gear and keep the hum and hiss aspects of system noise level in check. The university's cutting edge researchers were providing all of the source effects along with their software to automatically test subjects as schedules permitted 24/7/365. They were testing subjects ranging from those born profoundly deaf all the way through to those with "normal" hearing. All of their research was aimed at understanding how to deal with maintaining / enhancing directional cues. They were seeking to learn how to avoid / cure situations where people with various degrees of hearing loss could find themselves in the center of a busy crosswalk hearing a siren approaching but not knowing which way to proceed to best avoid it. Their goal was to put in place a system with card access that would admit card holders 24/7/365, run a series of tests record their reactions and time stamp when they entered and left. The company I was free-lancing for had no part in any of the front end design or any of the software and testing procedures. Here are a few examples of where the senior researchers said they were heading. A mag card holding subject would enter the anti room and proceed into the semi anechoic acoutstic chamber when the previous occupant exited. The subject was to indicate when they were accurately positioned and ready to proceed. The following examples are a few they were planning to begin with: You're in the middle of a cocktail party surrounded by a crowd of guests coming and going while chattering about a variety of subjects. A voice would then ask the subject to point towards the lady talking about the color of her purse. The scenario was to repeat until the subject pointed at one of the 64 speakers whereupon the choice was to be recorded and a new scenario would begin. Possibly this scenario would have the subject walking down a street and arriving at a busy intersection where they would need to listen for various instructions such as a police officer or enunciators indicating walk, don't walk and in which direction. They were planning to develop a number of scenarios and record them all in quad with a then new mic from Shoeps (Sp?) or Calrec. They were planning to run these tests for years always keeping track of which scenarios a test subject last heard and the directional choices they made. A subject could visit as often as they liked and for as long as they liked and over a period of time they'd have heard some scenarios many times with the software adjusting various aspects of directional cuing each time they visited. This was installed some years back and I've never followed up on where their research led them but I do know their lead researchers have given lectures over the years at various AES conventions and are working at the bleeding edge of this research. Oticon footed the bill for the chamber and a number of sources were contributing to their costs over the years. @Dionysis works in this university town and may be aware of the work. My main comment? I chuckle a lot when folks tell me their BSS gear or QSC amps are too noisy. Finely / carefully setting the gain structures on 64 channels operating as a spherical array housed within a semi-anechoic acoustic chamber definitely fine tuned my practices for setting gain structures. We were to develop structures to repeatedly and accurately position the speakers at distances of 1, 1.5 and 2.0 Meters from the theoretical centers of test subjects skulls. The 1.0 Meter distance proved to be unobtainable due to the physical dimensions of the 64 speakers and the need to accommodate the stool and the heights of the various unknown test subjects. University of Western Ontario, located in London, Ontario has an entire building devoted to various aspects of hearing, hearing care and cutting edge research into various aspects of hearing. They were planning this to be a multi million dollar / multi year project specifically into how to optimize directional cues for folks afflicted with all manners of hearing disorders. It shouldn't be too difficult to learn more about it on line.
    I sure hope this doesn't vaporize when I hit Post.
    Toodleoo!
    Ron Hebbard.
     
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  8. jonliles

    jonliles Active Member Fight Leukemia

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    Bill-
    What mic do you use to feed the board if the actors are not mic'd, which 99% of the time the are not. This space uses a full X32, so lot's of Aux outs or direct outs.

    All-
    Thanks for the inputs!

    Jon
     
  9. FMEng

    FMEng Well-Known Member Fight Leukemia

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    I'm no expert, but I have done quite a bit of research on loop systems. The problem with loop systems is that, in most spaces, the required placement of loops would require tearing up and replacing floor coverings. One, perimeter loop isn't enough. They would be my preferred choice when building new or making major remodels. Otherwise, I would choose FM (72/75 MHz). Williams Sound, Telex, and Listen Technologies all make them.
     
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  10. MNicolai

    MNicolai Well-Known Member Fight Leukemia

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    Indeed, a hearing loop is a massive undertaking if not done in concert with a larger project involving refinishing the floor and remounting any fixed seating. For a very small room where you can just do the perimeter, it is not as bad, but it still involves some form of carpet work and/or saw-cutting the floor. Attached is a shot from one I worked on last year. Seating guys came in first, shoot their points from a $50,000 3D-surveying tool, then we came in after to lay out the loop wire between the rows. Laying the wire is a 3 person job. After entire path is painted on the floor, one person goes along with flat copper wire, another person behind them doing a layer of gaff tape, and another person behind them doing an additional layer of gaff. Has to be done before the carpet goes in but after all of the heavy construction traffic is out of the room.

    A layout like this involves a lot of heavy-duty soldering at each corner.hen we left the wires were hooked up to a continuity meter hooked up to an alarm. If the seating or carpet guys did anything to break continuity (which they did), an alarm goes off with a sign posted next to it to call us immediately. Inevitably, 2 repairs were made on-site that involved peeling up carpet and laying it back down.

    CELA Loop.jpg

    Important to note: an induction hearing loop does not preclude you from having to provide receivers. You still need to have devices you can hand out to people -- the same number of receivers as you are required to have if you had an FM or IR assistive listening system.

    To answer the original question though:

    1) I specify Listen 72MHz FM frequently. It's not rocket science and a similar product from Williams Sound or anyone else is probably fine, but Listen gives me a lot of support when I do loop designs with them, and for higher-use systems I like their iDSP receivers. In particular, I avoid 216MHz because this frequency range gets hit frequently with interference from lighting ballasts.

    2) My go-to is the Shure VP88. I've used them in dozens of projects and they always deliver. My preference is to take both channels of this mic into a DSP with an additional feed from the console. The console feed is for injecting vocals and when the DSP receives signal from the console feed, it ducks the house mic below the console signal. So let's say it's a musical act, the house mic picks up the room sound and everything through the PA, but the console directly injects a vocals mix that rides on top of the house mic feed. This gives crystal clear articulation of speech and voice to patrons, while also giving them a spruce of the energy in the room (applause, cheering, laughing, etc).

    I prefer not relying on a console to drive the ALS system. For acoustic events where the console isn't turned on or even just cases where the FOH engineer doesn't know or doesn't care about the house mic feed for ALS, the DSP can do all of the heavy lifting and make certain no matter what, patrons are receiving an audio feed at a reliable, consistent level.
     
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  11. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    Please keep us up to date on how you're doing, whether or not you proceed with your BAHA and, of particular interest to me, how satisfied you are, or aren't, with your stereo imaging.
    Thanks in advance.
    Toodleoo!
    Ron Hebbard.
     
  12. Moose Hatrack

    Moose Hatrack Active Member

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    Thank you Ron, I certainly will keep you updated. I enjoyed the description of the chamber and I was especially pleased to read that it was funded by Oticon. I've pretty much selected the Oticon Ponto system if I can't get successful reconstructive surgery. Your description of the semi anechoic acoustic chamber reminded me of this installation: . The art installation is HO scale by comparison, but fascinating nonetheless! We hope to hear this piece this weekend.
     
  13. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    Five part harmony blown out to 40 voices emanating from 40 discreet locations leaves barbershop in the dust.
    In the sixties, I found myself operating the sound and light show at a historic castle in Hamilton, Ontario. I had no part in the installation, was merely the operator. The lighting was a Strand, 3 manual preset, system LC with 24 saturable core dimmers driving both interior and exterior lights but the sound was more interesting with three tracks of audio spread across a pair of heavily modified Phillips home decks plus a control track stepping a mechanical switcher routing the 70 volt outputs of three amplifiers through various combinations of speakers in the trees surrounding the castle. The castle installation was before TEAC introduced 1/4" four track simultaneous tape to the lower budget world. In the seventies I moved on to Head of Sound at the Stratford Shakespearean Festival's main stage where our custom Ward Beck console routed 12 inputs out 24 outputs via a 288 pushbutton manual matrix driving 24 channels of Crown through 24 Tannoy Belvedere's, a couple of Altec A7's and a mono cluster of JBL 15's and 2350's. Stratford always brought in composers and wrote original music to be played live by our house orchestra and / or recorded. Many composers saw the seamless integration of effects into the productions as part of their responsibilities. When I was subcontracted to the contractor who won the toss for the 64 channel installation in the hemi-anechoic chamber I just couldn't say no. Mono's O.K. Stereo's better and quad and 5.1 /7.1 take things even further but the home audio guys are in the dust when it comes to having 64 discreet channels to play with. A gentleman named Vijay Parsa was heading the project for The University of Western Ontario. I know Vijay, and some of his associates, gave speeches at several A.E.S. conferences but I've no idea where their work lead them or if the installation is still intact.
    Do keep us up to date on the status of your hearing in general and your perception of directional cues in particular.
    Thanks for sharing your situation with us Moose.
    Toodleoo!
    Ron Hebbard.
     
    Last edited: Feb 21, 2017

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